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Sample records for energy converters based

  1. Thermal to electrical energy converter based on black Si

    NASA Astrophysics Data System (ADS)

    Nishijima, Y.; Balčytis, A.; Komatsu, R.; Yamamura, T.; Seniutinas, G.; Wong, B. T.; Juodkazis, S.

    2015-03-01

    Photo-thermal - to - electrical converter is demonstrated by using a commercial Peltier Bi-Te element with a hot contact made out of nanotextured Si (black-Si). Black-Si with colloidal Au nanoparticles is shown to further increase the efficiency of thermal-to-electrical conversion. Peculiarities of heat harvesting using black-Si with plasmonic Au nanoparticles at different gold densities are analyzed. Solar radiation absorption and electric field enhancement in plain and Au nanoparticle decorated black-Si was simulated using finite difference time domain (FDTD) method. Thermal conduction in nanotextured black-Si was explained using phonon Monte-Carlo simulations at the nanoscale. Strategies for creating larger thermal gradient on Peltier element using nanotextured light absorbers is discussed.

  2. Gallium phosphide energy converters

    NASA Technical Reports Server (NTRS)

    Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

    1995-01-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

  3. Thermionic photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  4. Cycloidal Wave Energy Converter

    SciTech Connect

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

  5. Thermionic energy converters

    DOEpatents

    Monroe, Jr., James E.

    1977-08-09

    A thermionic device for converting nuclear energy into electrical energy comprising a tubular anode spaced from and surrounding a cylindrical cathode, the cathode having an outer emitting surface of ruthenium, and nuclear fuel on the inner cylindrical surface. The nuclear fuel is a ceramic composition of fissionable material in a metal matrix. An axial void is provided to collect and contain fission product gases.

  6. Single stage AC-DC converter for Galfenol-based micro-power energy harvesters

    NASA Astrophysics Data System (ADS)

    Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

    2014-06-01

    Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.

  7. Parametric energy converter

    SciTech Connect

    Johnson, R.N.

    1981-10-20

    A method and apparatus for converting thermal energy into mechanical energy by parametric pumping of rotary inertia. In a preferred embodiment, a modified tesla turbine rotor is positioned within a rotary boiler along its axis of rotation. An external heat source, such as solar radiation, is directed onto the outer casing of the boiler to convert the liquid to steam. As the steam spirals inwardly toward the discs of the rotor, the moment of inertia of the mass of steam is reduced to thereby substantially increase its kinetic energy. The laminar flow of steam between the discs of the rotor transfers the increased kinetic energy to the rotor which can be coupled out through an output shaft to perform mechanical work. A portion of the mechanical output can be fed back to maintain rotation of the boiler.

  8. Thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (Inventor)

    1983-01-01

    The efficiency of thermionic energy converters is improved by internal distribution of tiny sorted cesium diodes driven by the thermal gradient between the primary emitter and the collector. The tiny, sorted diode distribution comprises protrusions of the emitter material from the main emitter face which contact the main collector face thermally but not electrically. The main collector ends of the protrusions are separated from the main collector by a thin layer of insulation, such as aluminum oxide. The shorted tiny diode distribution augments cesium ionization through internal thermal effects only within the main diode. No electrical inputs are required. This ionization enhancement by the distribution of the tiny shorted diodes not only reduces the plasma voltage drop but also increases the power output and efficiency of the overall thermionic energy converter.

  9. Novel Control for Voltage Boosted Matrix Converter based Wind Energy Conversion System with Practicality

    NASA Astrophysics Data System (ADS)

    Kumar, Vinod; Joshi, Raghuveer Raj; Yadav, Dinesh Kumar; Garg, Rahul Kumar

    2016-06-01

    This paper presents the implementation and investigation of novel voltage boosted matrix converter (MC) based permanent magnet wind energy conversion system (WECS). In this paper, on-line tuned adaptive fuzzy control algorithm cooperated with reversed MC is proposed to yield maximum energy. The control system is implemented on a dSPACE DS1104 real time board. Feasibility of the proposed system has been experimentally verified using a laboratory 1.2 kW prototype of WECS under steady-state and dynamic conditions.

  10. The effect of converter efficiency on DEAP-based energy conversion: an overview and optimization method

    NASA Astrophysics Data System (ADS)

    van Kessel, Rick; Wattez, Ambroise; Bauer, Pavol

    2014-03-01

    This work presents an integral approach to the power electronic challenges that are faced in DEAP-based energy conversion, such as wide converter operating ranges and high peak-to-average ratios. It is shown that for small strain cycles, the losses in the Power Electronic Converter (PEC) due to the cyclic charging and discharging are dominant. The efficiency profile of a realistic, high-voltage modular PEC was measured and fed into an optimization algorithm. The current amplitude, phase and shape are optimized, and different cycle types are compared. With optimization results for a wide strain range, it is demonstrated that with properly adapted harvesting cycles, the overall conversion efficiency is significantly improved, especially for small strain cycles.

  11. Electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L. (Inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  12. Wind/water energy converter

    NASA Technical Reports Server (NTRS)

    Paulkovich, J.

    1979-01-01

    Device will convert wind, water, tidal or wave energy into electrical or mechanical energy. Is comprised of windmill-like paddles or blades synchronously geared to orient themselves to wind direction for optimum energy extraction.

  13. Oscillating-water-column wave-energy-converter based on dielectric elastomer generator

    NASA Astrophysics Data System (ADS)

    Vertechy, R.; Fontana, M.; Rosati Papini, G. P.; Bergamasco, M.

    2013-04-01

    Dielectric Elastomers (DE) have been largely studied as actuators and sensors. Fewer researches have addressed their application in the field of energy harvesting. Their light weightiness, low cost, high corrosion resistance, and their intrinsic high-voltage and cyclical-way of operation make DE suited for harvesting mechanical energy from sea waves. To date, the development of cost-effective Wave Energy Converters (WECs) is hindered by inherent limitations of available material technologies. State of the art WECs are indeed based on traditional mechanical components, hydraulic transmissions and electromagnetic generators, which are all made by stiff, bulky, heavy and costly metallic materials. As a consequence, existing WECs result in being expensive, difficult to assemble, sensitive to corrosion and hard to maintain in the marine environment. DE generators could be an enabling technology for overcoming the intrinsic limitations of current WEC technologies. In this context, this paper focuses on Polymer-based Oscillating-Water-Column (Poly-OWC) type WECs, and analyzes the viability of using DE generators as power-take-off systems. Regarding paper structure, the first sections introduce the working principle of OWC devices and discuss possible layouts for their DE-based power-take-off system. Then, a simplified hydraulic-electro-hyperelastic model of a two-dimensional Poly-OWC is described. Finally, preliminary simulation results are shown which provide insights on the potential capabilities of Poly-OWC.

  14. Thermophotovoltaic energy converters based on thin film selective emitters and InGaAs photovoltaic cells

    SciTech Connect

    Fatemi, N.S.; Hoffman, R.H.; Wilt, D.M.; Lowe, R.A.; Garverick, L.M.; Scheiman, D.

    1996-02-01

    This paper presents the results of an investigation to demonstrate thermophotovoltaic energy conversion using InGaAs photovoltaic cells, yttrium-aluminum-garnet- (YAG-) based selective emitters, and bandpass/reflector filters, with the heat source operating at 1100{degree}C. InGaAs cells were grown on InP by organometallic vapor phase epitaxy with bandgaps of 0.60 and 0.75 eV and coupled to Ho-, Er-, and Er-Tm-doped YAG selective emitters. Infrared reflector and/or shortpass filters were also used to increase the ratio of in-band to out-of-band radiation from the selective emitters. Efficiencies as high as 13.2{percent} were recorded for filtered converters. {copyright} {ital 1996 American Institute of Physics.}

  15. Proposed electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  16. Bidirectional frequency tuning of a piezoelectric energy converter based on a cantilever beam

    NASA Astrophysics Data System (ADS)

    Eichhorn, C.; Goldschmidtboeing, F.; Woias, P.

    2009-09-01

    A piezoelectric energy converter is presented, whose resonance frequency can be tuned by applying mechanical stress to its structure. The converter consists of a piezo-polymer cantilever beam with two additional thin arms, which are used to apply an axial preload to the tip of the beam. The compressive or tensile prestress applied through the arms leads to a shift of the beam's resonance frequency. Experiments with this structure indicate a high potential: the resonance frequency of a harvester to which a compressive preload was applied could be altered from 380 Hz to 292 Hz. In another experiment, a harvester with stiffened arms was tuned from 440 Hz to 460 Hz by applying a tensile preload. In combination with automatic control of the applied force, this type of structure could be used to enhance the performance of energy harvesters in vibrating environments with occasional shifts of the vibrational frequency.

  17. Ocean tide energy converter

    SciTech Connect

    Rainey, D.E.

    1980-06-24

    A tide motor energy source includes a tidal piston with a valved chamber. The piston drives a hydraulic ram to generate electrical power through a pressure accumulator and hydraulic motor. The ram can be locked hydraulically to enable the tidal piston to be held fixed at a desired elevation and the valves in the chamber permit it to be filled with water or air. The piston with its chamber filled with air at its low tide position and then released for controlled ascent while submerged acts as a submerged float for driving the ram upwardly while the tide runs in during one phase of its operation. The piston with its chamber filled with water while locked at its highest position as the tide begins to run out, and then released to fall under control, acts as a weight suspended in air after the water level drops below the piston for driving the ram downwardly during the second phase of its operation. The rising and falling motion of the tidal piston is used as the energy source.

  18. Gallium phosphide energy converters

    NASA Technical Reports Server (NTRS)

    Sims, P. E.; DiNetta, Louis C.; DuganCavanagh, K.; Goetz, M. A.

    1996-01-01

    Betavoltaic power supplies based on gallium phosphide can supply long term low-level power with high reliability. Results are presented for GaP devices powered by Ni-63 and tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/cm(exp 2) have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. A small demonstration system has been assembled that generates and stores enough electricity to light up an LED.

  19. Multicriteria analysis to evaluate wave energy converters based on their environmental impact: an Italian case study

    NASA Astrophysics Data System (ADS)

    Azzellino, Arianna; Contestabile, Pasquale; Lanfredi, Caterina; Vicinanza, Diego

    2010-05-01

    The exploitation of renewable energy resources is fast becoming a key objective in many countries. Countries with coastlines have particularly valuable renewable energy resources in the form of tides, currents, waves and offshore wind. Due to the visual impact of siting large numbers of energy generating devices (eg. wind turbines) in terrestrial landscapes, considerable attention is now being directed towards coastal waters. Due to their environmental sensitivity, the selection of the most adequate location for these systems is a critical factor. Multi-criteria analysis allows to consider a wide variety of key characteristics (e.g. water depth, distance to shore, distance to the electric grid in land, geology, environmental impact) that may be converted into a numerical index of suitability for different WEC devices to different locations. So identifying the best alternative between an offshore or a onshore device may be specifically treated as a multicriteria problem. Special enphasisi should be given in the multicriteria analysis to the environmental impact issues. The wave energy prospective in the Italian seas is relatively low if compared to the other European countries faced to the ocean. Based on the wave climate, the Alghero site, (NW Sardinia, Italy) is one of the most interesting sites for the wave energy perspective (about 10 kW/m). Alghero site is characterized by a high level of marine biodiversity. In 2002 the area northern to Alghero harbour (Capo Caccia-Isola Piana) was established a Marine Protected Area (MPA). It could be discussed for this site how to choose between the onshore/offshore WEC alternative. An offshore device like Wave Dragon (http://www.wavedragon.net/) installed at -65m depth (width=300m and length=170 m) may approximately produce about 3.6 GWh/y with a total cost of about 9,000,000 €. On the other hand, an onshore device like SSG (http://waveenergy.no/), employed as crown wall for a vertical breakwater to enlarge the present

  20. Electromechanical behavior of a pendulum-based piezoelectric frequency up-converting energy harvester

    NASA Astrophysics Data System (ADS)

    Ramezanpour, Reza; Nahvi, Hassan; Ziaei-Rad, Saeed

    2016-05-01

    In the present study, the possibility to extract more vibrational energy by utilizing a high number of magnets on the proof mass of a piezoelectric frequency up-converting energy harvester is investigated. Due to magnetic interaction, the beam is actuated whenever the proof mass passes over its tip. It is observed that several peaks occur in the voltage signal of PZT beam when the angular velocity of the proof mass increases linearly. It is shown that the peaks locations which found to be dependent on the natural frequency of the PZT beam as well as the number of rotating magnets can be estimated by a mathematical formulation. Considering the effects of magnetic interactions on the pendulum dynamics, the generated power of the harvester is obtained for harmonic excitations. Although the determination of exact optimum number of magnets that can lead to the best generated power in all excitation characteristics is impossible, it is found that by applying an appropriate number of rotating magnets (e.g. six, seven or eight magnets), the extracted power from high amplitude excitations can be enhanced. It is noteworthy that, at some particular cases, it is possible that the generated power be increased to even more than ten times. At the end, by conducting some experiments, the validity of the mathematical modeling as well as the applied numerical method is examined.

  1. Large wind energy converter: Growian 3 MW

    NASA Technical Reports Server (NTRS)

    Koerber, F.; Thiele, H. A.

    1979-01-01

    The main features of the Growian wind energy converter are presented. Energy yield, environmental impact, and construction of the energy converter are discussed. Reliability of the windpowered system is assessed.

  2. Boost matrix converters in clean energy systems

    NASA Astrophysics Data System (ADS)

    Karaman, Ekrem

    This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

  3. A new biosensor for glucose determination in serum based on up-converting fluorescence resonance energy transfer.

    PubMed

    Peng, Jianhong; Wang, Yuhui; Wang, Jialan; Zhou, Xin; Liu, Zhihong

    2011-10-15

    In this work, a new glucose sensor based on up-converting fluorescence resonance energy transfer (UC-FRET) was developed. Up-converting phosphors (UCPs, NaYF(4): Yb, Er), which were covalently labeled with Concanavalin A (ConA), were used as the energy donor with thiolated β-cyclodextrins (SH-β-CDs) functionalized gold nanoparticles as the energy acceptor. Due to the combination between ConA and SH-β-CDs, the energy donor and the acceptor were brought to close proximity, resulting in the quenching of the fluorescence of UCPs by gold nanoparticles. In the presence of glucose which competed with SH-β-CDs towards the binding sites of ConA, the biosensor (UCPs-ConA-SH-β-CDs-Au) was decomposed and the energy donor was separated from the acceptor. Therefore, the fluorescence of UCPs was restored dependent on the concentration of glucose. The increase of UCPs fluorescence intensity was proportional to glucose concentration within the range from 0.4 μM to 10μM in aqueous buffer, with a limit of detection (LOD) of 0.043 μM. A same linear range of glucose concentration was obtained in a human serum matrix (which was pretreated and thus contained no glucose) with a slightly higher LOD (0.065 μM). The glucose sensor was applied to real human serum samples with the results consistent with that of a classic hexokinase (HK) method, indicating that the UC-FRET biosensor was competent for directly sensing glucose in serum samples without optical interference, which benefited from the near infrared (NIR) excitation nature of UCPs. The results of this work suggested that the UC-FRET technique could be a promising alternative for detecting biomolecules in complex biological sample matrixes for diagnostic purposes. PMID:21852101

  4. Parametric study of laser photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  5. A method for EIA scoping of wave energy converters-based on classification of the used technology

    SciTech Connect

    Margheritini, Lucia; Hansen, Anne Merrild; Frigaard, Peter

    2012-01-15

    During the first decade of the 21st Century the World faces spread concern for global warming caused by rise of green house gasses produced mainly by combustion of fossil fuels. Under this latest spin all renewable energies run parallel in order to achieve sustainable development. Among them wave energy has an unequivocal potential and technology is ready to enter the market and contribute to the renewable energy sector. Yet, frameworks and regulations for wave energy development are not fully ready, experiencing a setback caused by lack of understanding of the interaction of the technologies and marine environment, lack of coordination from the competent Authorities regulating device deployment and conflicts of maritime areas utilization. The EIA within the consent process is central in the realization of full scale devices and often is the meeting point for technology, politics and public. This paper presents the development of a classification of wave energy converters that is based on the different impact the technologies are expected to have on the environment. This innovative classification can be used in order to simplify the scoping process for developers and authorities.

  6. Ocean floor mounting of wave energy converters

    SciTech Connect

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  7. Controller for a wave energy converter

    SciTech Connect

    Wilson, David G.; Bull, Diana L.; Robinett, III, Rush D.

    2015-09-22

    A wave energy converter (WEC) is described, the WEC including a power take off (PTO) that converts relative motion of bodies of the WEC into electrical energy. A controller controls operation of the PTO, causing the PTO to act as a motor to widen a wave frequency spectrum that is usable to generate electrical energy.

  8. Radiant energy to electric energy converter

    NASA Technical Reports Server (NTRS)

    Sher, Arden (Inventor)

    1980-01-01

    Radiant energy is converted into electric energy by irradiating a capacitor including an ionic dielectric. The dielectric is a sintered crystal superionic conductor, e.g., lanthanum trifluoride, lanthanum trichloride, or silver bromide, so that a multiplicity of crystallites exist between electrodes of the capacitor. The radiant energy cyclically irradiates the dielectric so that the dielectric exhibits a cyclic photocapacitive like effect. Adjacent crystallites have abutting surfaces that enable the crystallites to effectively form a multiplicity of series capacitor elements between the electrodes. Each of the capacitor elements has a dipole layer only on or near its surface. The capacitor is initially charged to a voltage just below the dielectric breakdown voltage by connecting it across a DC source causing a current to flow through a charging resistor to the dielectric. The device can be utilized as a radiant energy detector or as a solar energy cell.

  9. Design of the dual-buoy wave energy converter based on actual wave data of East Sea

    NASA Astrophysics Data System (ADS)

    Kim, Jeongrok; Kweon, Hyuck-Min; Jeong, Weon-Mu; Cho, Il-Hyoung; Cho, Hong-Yeon

    2015-07-01

    A new conceptual dual-buoy Wave Energy Converter (WEC) for the enhancement of energy extraction efficiency is suggested. Based on actual wave data, the design process for the suggested WEC is conducted in such a way as to ensure that it is suitable in real sea. Actual wave data measured in Korea's East Sea (position: 36.404 N° and 129.274 E°) from May 1, 2002 to March 29, 2005 were used as the input wave spectrum for the performance estimation of the dual-buoy WEC. The suggested WEC, a point absorber type, consists of two concentric floating circular cylinders (an inner and a hollow outer buoy). Multiple resonant frequencies in proposed WEC affect the Power Ttake-off (PTO) performance of the WEC. Based on the numerical results, several design strategies are proposed to further enhance the extraction efficiency, including intentional mismatching among the heave natural frequencies of dual buoys, the natural frequency of the internal fluid, and the peak frequency of the input wave spectrum.

  10. Semiconductor electrolyte photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Anderson, W. W.; Anderson, L. B.

    1975-01-01

    Feasibility and practicality of a solar cell consisting of a semiconductor surface in contact with an electrolyte are evaluated. Basic components and processes are detailed for photovoltaic energy conversion at the surface of an n-type semiconductor in contact with an electrolyte which is oxidizing to conduction band electrons. Characteristics of single crystal CdS, GaAs, CdSe, CdTe and thin film CdS in contact with aqueous and methanol based electrolytes are studied and open circuit voltages are measured from Mott-Schottky plots and open circuit photo voltages. Quantum efficiencies for short circuit photo currents of a CdS crystal and a 20 micrometer film are shown together with electrical and photovoltaic properties. Highest photon irradiances are observed with the GaAs cell.

  11. Silicon waveguide based TE mode converter.

    PubMed

    Zhang, Jing; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

    2010-11-22

    A silicon waveguide based TE mode converter was designed for the mode conversion between a horizontal waveguide and vertical waveguide in the two-layer structure waveguide based polarization diversity circuit. The TE mode converter's performance was studied. The polarization mode converter with minimum length of 5 μm was demonstrated to provide the TE mode conversion while maintaining the polarization status. The insertion loss at the transition region was less than 2 dB. PMID:21164874

  12. WEC-Sim (Wave Energy Converter - SIMulator)

    Energy Science and Technology Software Center (ESTSC)

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-sourcemore » code to model WECs.« less

  13. Hydrodynamic Performance of a Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Yang, Yingchen

    2010-11-01

    To harvest energy from ocean waves, a new wave energy converter (WEC) was proposed and tested in a wave tank. The WEC freely floats on the water surface and rides waves. It utilizes its wave-driven angular oscillation to convert the mechanical energy of waves into electricity. To gain the maximum possible angular oscillation of the WEC under specified wave conditions, both floatation of the WEC and wave interaction with the WEC play critical roles in a joint fashion. During the experiments, the submersion condition of the WEC and wave condition were varied. The results were analyzed in terms of the oscillation amplitude, stability, auto-orientation capability, and wave frequency dependency.

  14. Solar energy converter using surface plasma waves

    NASA Technical Reports Server (NTRS)

    Anderson, L. M. (Inventor)

    1984-01-01

    Sunlight is dispersed over a diffraction grating formed on the surface of a conducting film on a substrate. The angular dispersion controls the effective grating period so that a matching spectrum of surface plasmons is excited for parallel processing on the conducting film. The resulting surface plasmons carry energy to an array of inelastic tunnel diodes. This solar energy converter does not require different materials for each frequency band, and sunlight is directly converted to electricity in an efficient manner by extracting more energy from the more energetic photons.

  15. WEC-Sim (Wave Energy Converter - SIMulator)

    SciTech Connect

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-source code to model WECs.

  16. Ocean wave energy converting vessel

    SciTech Connect

    Boyce, P.F.

    1986-08-26

    An ocean wave energy conversion system is described comprised of a four beam quadrapod supported by bouyant members from which is suspended a pendulum. The pendulum contains a vertical generator shaft and a generator, the generator shaft being splined and fitted with two racheted pulleys, the pulleys being looped, one clockwise and one counterclockwise with separate cables. The cables are attached at their ends to the bow and stern of the quadrapod, whereby the generator shaft will pin when the quadrapod rocks over waves and the pendulum tends toward the center of earth.

  17. Solar energy recorder. [for converter site selection

    NASA Technical Reports Server (NTRS)

    Lollar, R. B.; Mandt, R. R.

    1974-01-01

    A serious obstacle to the large-scale terrestrial application of solar energy lies in the scarcity of reliable data on the amount of solar energy at candidate converter sites. This paper describes a system designed to monitor and record, automatically, the values of the direct and total (sun and sky) solar radiation which would be seen by either tracking or fixed-type solar converters. A further pressing need addressed by the system is the means for efficiency testing and evaluation of solar cells, solar collectors and solar concentrator systems, under outdoor exposure to natural sunlight and weather conditions for extended periods. The design was accomplished in support of the Marshall Space Flight Center, NASA, where design concepts and materials for large-scale terrestrial solar energy converters are currently being evaluated.

  18. FPGA-based time to digital converter and data acquisition system for high energy tagger of KLOE-2 experiment

    NASA Astrophysics Data System (ADS)

    Iafolla, L.; Balla, A.; Beretta, M.; Ciambrone, P.; Gatta, M.; Gonnella, F.; Mascolo, M.; Messi, R.; Moricciani, D.; Riondino, D.

    2013-08-01

    In order to reconstruct γγ physics events tagged with High Energy Tagger (HET) in the KLOE-2 (K LOng Experiment 2), we need to measure the Time Of Flight (TOF) of the electrons and positrons from the KLOE-2 Interaction Point (IP) to our tagging stations (11 m apart). The required resolution must be better than the bunch spacing (2.7 ns). We have developed and implemented on a Xilinx Virtex-5 FPGA a Time to Digital Converter (TDC) with 625 ps resolution (LSB) along with an embedded data acquisition system and the interface to the online FARM of KLOE-2. We will describe briefly the architecture of the TDC and of the Data AcQuisition (DAQ) system. Some more details will be provided about the zero-suppression algorithm used to reduce the data throughput.

  19. Energy utilization in fluctuating biological energy converters

    PubMed Central

    Szőke, Abraham; Hajdu, Janos

    2016-01-01

    We have argued previously [Szoke et al., FEBS Lett. 553, 18–20 (2003); Curr. Chem. Biol. 1, 53–57 (2007)] that energy utilization and evolution are emergent properties based on a small number of established laws of physics and chemistry. The relevant laws constitute a framework for biology on a level intermediate between quantum chemistry and cell biology. There are legitimate questions whether these concepts are valid at the mesoscopic level. Such systems fluctuate appreciably, so it is not clear what their efficiency is. Advances in fluctuation theorems allow the description of such systems on a molecular level. We attempt to clarify this topic and bridge the biochemical and physical descriptions of mesoscopic systems. PMID:27191009

  20. Wind energy converter utilizing vortex augmentation

    SciTech Connect

    Edwards, S. S.

    1985-05-14

    A wind energy conversion apparatus is disclosed herein for converting the linear momentum of wind energy into a pair of concentrated, counter-rotating and side-by-side regions of high angular momentum which includes a wing having variable angle of attack positionable forward of the entrance to an elongated duct having a bell mouth including an upper, inner reflex angular surface leading into a bifurcated duct section terminating in a diffuser augmenter at the aft facing area of the duct and which includes propellors operable to extract energy from the angular momentum in the established regions for driving electric generators or generator therefrom.

  1. Microbial fuel cell energy harvesting using synchronous flyback converter

    NASA Astrophysics Data System (ADS)

    Alaraj, Muhannad; Ren, Zhiyong Jason; Park, Jae-Do

    2014-02-01

    Microbial Fuel Cells (MFCs) use biodegradable substrates, such as wastewater and marine sediments to generate electrical energy. To harvest more energy from an MFC, power electronic converters have recently been used to replace resistors or charge pumps, because they have superior controllability on MFC's operating point and higher efficiency in energy storage for different applications. Conventional diode-based energy harvesters suffer from low efficiency because of the energy losses through the diode. Replacing the diode with a MOSFET can reduce the conduction loss, but it requires an isolated gate signal to control the floating secondary MOSFET, which makes the control circuitry complex. This study presents a new MFC energy harvesting regime using a synchronous flyback converter, which implements a transformer-based harvester with much simpler configuration and improves harvesting efficiency by 37.6% compared to a diode based boost converter, from 33.5% to 46.1%. The proposed harvester was able to store 2.27 J in the output capacitor out of 4.91 J generated energy from the MFC, while the boost converter can capture 1.67 J from 4.95 J.

  2. Energy Savings Assessment for Digital-to-Analog Converter Boxes

    SciTech Connect

    Cheung, Hoi Ying Iris; Meier, Alan; Brown, Richard

    2011-01-18

    The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.

  3. Performance of an angular flange aeroelastic wind energy converter

    SciTech Connect

    Ahmadi, G.

    1983-05-01

    ALL conventional wind turbines operate on the principles of turbomachinaries, with wind being made to flow over a set of rotating vanes. Recently, a new concept for wind energy conversion based on aeroelastic instability was introduced. It is well known that couplings between the vibration of an elastic structure and fluid stream may lead to aeroelastic instability. Energy then is transferred from the airstream into the elastic structure, which results in a destructive monotonic increase of the vibration amplitude of the structure. The failure of the Tacoma Narrows Bridge is one of the well-known examples of such a disaster. The use of an aeroelastic instability (or flutter) mechanism for constructing a wind energy converter was suggested. The theory for a torsional wind energy converter and the results of some model tests were also presented. Recently, some studies on similar types of wind energy converters using oscillating airfoils were reported. In the present study an angular flange H-section model of a torsional aeroelastic wind energy converter is constructed, and its performances under various conditions are investigated. The effects of the variations of the flange angle and the flange width on the performance of the model are studied. The weight of the pendulum is also varied, and its effects on the power coefficient of the model are investigated. It is observed that the efficiency of energy conversion decreases with an increase in wind speed. A method for possible improvement of the theoretical prediction is suggested and discussed.

  4. Clustering of cycloidal wave energy converters

    DOEpatents

    Siegel, Stefan G.

    2016-03-29

    A wave energy conversion system uses a pair of wave energy converters (WECs) on respective active mountings on a floating platform, so that the separation of the WECs from each other or from a central WEC can be actively adjusted according to the wavelength of incident waves. The adjustable separation facilitates operation of the system to cancel reactive forces, which may be generated during wave energy conversion. Modules on which such pairs of WECs are mounted can be assembled with one or more central WECs to form large clusters in which reactive forces and torques can be made to cancel. WECs of different sizes can be employed to facilitate cancelation of reactive forces and torques.

  5. A Novel Integrated Magnetic Structure Based DC/DC Converter for Hybrid Battery/Ultracapacitor Energy Storage Systems

    SciTech Connect

    Onar, Omer C

    2012-01-01

    This manuscript focuses on a novel actively controlled hybrid magnetic battery/ultracapacitor based energy storage system (ESS) for vehicular propulsion systems. A stand-alone battery system might not be sufficient to satisfy peak power demand and transient load variations in hybrid and plug-in hybrid electric vehicles (HEV, PHEV). Active battery/ultracapacitor hybrid ESS provides a better solution in terms of efficient power management and control flexibility. Moreover, the voltage of the battery pack can be selected to be different than that of the ultracapacitor, which will result in flexibility of design as well as cost and size reduction of the battery pack. In addition, the ultracapacitor bank can supply or recapture a large burst of power and it can be used with high C-rates. Hence, the battery is not subjected to supply peak and sharp power variations, and the stress on the battery will be reduced and the battery lifetime would be increased. Utilizing ultracapacitor results in effective capturing of the braking energy, especially in sudden braking conditions.

  6. Mechanical vibration to electrical energy converter

    DOEpatents

    Kellogg, Rick Allen; Brotz, Jay Kristoffer

    2009-03-03

    Electromechanical devices that generate an electrical signal in response to an external source of mechanical vibrations can operate as a sensor of vibrations and as an energy harvester for converting mechanical vibration to electrical energy. The devices incorporate a magnet that is movable through a gap in a ferromagnetic circuit, wherein a coil is wound around a portion of the ferromagnetic circuit. A flexible coupling is used to attach the magnet to a frame for providing alignment of the magnet as it moves or oscillates through the gap in the ferromagnetic circuit. The motion of the magnet can be constrained to occur within a substantially linear range of magnetostatic force that develops due to the motion of the magnet. The devices can have ferromagnetic circuits with multiple arms, an array of magnets having alternating polarity and, encompass micro-electromechanical (MEM) devices.

  7. Image processing to optimize wave energy converters

    NASA Astrophysics Data System (ADS)

    Bailey, Kyle Marc-Anthony

    The world is turning to renewable energies as a means of ensuring the planet's future and well-being. There have been a few attempts in the past to utilize wave power as a means of generating electricity through the use of Wave Energy Converters (WEC), but only recently are they becoming a focal point in the renewable energy field. Over the past few years there has been a global drive to advance the efficiency of WEC. Placing a mechanical device either onshore or offshore that captures the energy within ocean surface waves to drive a mechanical device is how wave power is produced. This paper seeks to provide a novel and innovative way to estimate ocean wave frequency through the use of image processing. This will be achieved by applying a complex modulated lapped orthogonal transform filter bank to satellite images of ocean waves. The complex modulated lapped orthogonal transform filterbank provides an equal subband decomposition of the Nyquist bounded discrete time Fourier Transform spectrum. The maximum energy of the 2D complex modulated lapped transform subband is used to determine the horizontal and vertical frequency, which subsequently can be used to determine the wave frequency in the direction of the WEC by a simple trigonometric scaling. The robustness of the proposed method is provided by the applications to simulated and real satellite images where the frequency is known.

  8. Finite element analysis of combined magnetoelectric- electrodynamic vibration energy converter

    NASA Astrophysics Data System (ADS)

    Bradai, Sonia; Naifar, Slim; Kanoun, Olfa

    2015-12-01

    In this paper we report on the design and optimization of a novel combined vibration energy harvester based on the use of electrodynamic and magnetoelectric (ME) principles to increase the energy outcome of an electrodynamic harvester without significantly increasing its size. Thereby the most important aspect is the dependence of magnetic flux variation on design parameters, as is it is the decisive effect for energy conversion. Magnetic circuit form and magnetization are optimized for maximizing energy outcome. We conclude that better magnetic flux variation is reached for a magnetic circuit formed with two magnets stacked one within the other using the same magnetization. Results illustrate that the use of combined converter enables to enhance the performance of simple electrodynamic or ME converter.

  9. Fluid energy converting method and apparatus

    SciTech Connect

    Arnold, L.

    1980-01-22

    A method and apparatus are disclosed for converting the kinetic energy of a moving fluid stream into useful work by means of a cascade of thin airfoils positioned therein. In one embodiment, the airfoils are provided with at least two degrees of freedom and adjacent airfoils are movable out of phase. The airfoils are subjected to the aerodynamically induced oscillations caused by the aeroelastic phenomenon known as flutter and the oscillatory movement is then harnessed to do useful work. In an alternate embodiment, a cascade of airfoils is mechanically oscillated within a moving fluid stream to increase the propulsion of the fluid. Where the fluid is a liquid, the cascade includes a plurality of hydrofoils.

  10. Fluid energy converting method and apparatus

    SciTech Connect

    Arnold, L.

    1982-08-31

    There is disclosed a method and apparatus for converting the kinetic energy of a moving fluid stream into useful work by means of a cascade of thin airfoils positioned therein. In one embodiment, the airfoils are provided with at least two degrees of freedom and adjacent airfoils are movable out of phase. The airfoils are subjected to the aerodynamically induced oscillations caused by the aeroelastic phenomenon known as flutter and the oscillatory movement is then harnessed to do useful work. In an alternate embodiment, a cascade of airfoils is mechanically oscillated within a moving fluid stream to increase the propulsion of the fluid. Where the fluid is a liquid, the cascade includes a plurality of hydrofoils.

  11. Converting sensitive waste into cleaner energy

    SciTech Connect

    Schriner, D.; Skinner, R.

    1997-10-01

    The destruction of sensitive unclassified information (SUI) has always been expensive due to the need for special controls to ensure its protection from disclosure to unauthorized persons. The sensitive documents were shredded, buried at the landfill, or sent to a recycling company. The Department of Energy (DOE) Idaho National Engineering and Environmental Laboratory (INEEL), operated by Lockheed Martin Idaho Technologies Company (LMITCO), has created an innovative method to dispose of its sensitive unclassified paper waste which has security, economic, and environmental benefits. A new cubing facility at the INEEL converts office and industrial waste into compact cubes which are then combined with coal and burned as a source of heat and process steam to run the Idaho Chemical Processing Plant (ICPP) facility. The process-engineered fuel, consisting of 25% cubes and 75% coal, bums cleaner than coal with lower emissions of sulfur dioxide and nitrogen oxides. The alternative fuel also reduces fuel costs, eliminates paying a recycling company, reduces the expense of landfill disposal, increases the life of the landfill, and provides energy to operate a large facility. The Operations Security (OPSEC) team capitalized on this waste to energy technology by recommending that the large quantities of sensitive information (documents) generated at the INEEL be disposed of in this manner. In addition to the economic and environmental benefits, this disposal method minimizes the vulnerabilities of SUI from disclosure to unauthorized personnel. The {open_quotes}cuber{close_quotes} technology has potential application in government and industry for protection of SUI.

  12. Energy converting material for solar cell application

    NASA Astrophysics Data System (ADS)

    Pokhrel, Madhab; Kumar, G. A.; Sardar, Dhiraj K.

    2012-02-01

    In this paper, we discuss the concept of an efficient infrared upconverting phosphor as an energy converting material that could potentially improve the efficiency of Si solar cells in bifacial configuration. Basic spectroscopic studies of Yb and Er-doped La2O2S phosphor was reported with particular attention to its upconversion properties under 1550 nm excitation. Different concentrations of phosphors were synthesized by solid state flux fusion method. The phosphor powders were well crystallized in a hexagonal shape with an average size 300-400 nm. The most efficient upconverting sample (1%Yb: 9% Er doped La2O2S) was also studied under the illumination with infrared (IR) broad band spectrum above 1000 nm. Our measurements show that even with an excitation power density of 0.159 W/cm2 using a tungsten halogen lamp the material shows efficient upconversion corroborating the fact that the present phosphors could be potential candidates for improving the efficiency of the present Si solar cells.

  13. Aiding Design of Wave Energy Converters via Computational Simulations

    NASA Astrophysics Data System (ADS)

    Jebeli Aqdam, Hejar; Ahmadi, Babak; Raessi, Mehdi; Tootkaboni, Mazdak

    2015-11-01

    With the increasing interest in renewable energy sources, wave energy converters will continue to gain attention as a viable alternative to current electricity production methods. It is therefore crucial to develop computational tools for the design and analysis of wave energy converters. A successful design requires balance between the design performance and cost. Here an analytical solution is used for the approximate analysis of interactions between a flap-type wave energy converter (WEC) and waves. The method is verified using other flow solvers and experimental test cases. Then the model is used in conjunction with a powerful heuristic optimization engine, Charged System Search (CSS) to explore the WEC design space. CSS is inspired by charged particles behavior. It searches the design space by considering candidate answers as charged particles and moving them based on the Coulomb's laws of electrostatics and Newton's laws of motion to find the global optimum. Finally the impacts of changes in different design parameters on the power takeout of the superior WEC designs are investigated. National Science Foundation, CBET-1236462.

  14. 78 FR 40132 - Wave Energy Converter Prize Administration Webinar

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... of Energy Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar AGENCY: Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy (DOE). ACTION: Notice... available for public review on the DOE Office of Energy Efficiency and Renewable Energy (EERE) Web site...

  15. Potential of dual-energy subtraction for converting CT numbers to electron density based on a single linear relationship

    SciTech Connect

    Saito, Masatoshi

    2012-04-15

    Purpose: The conversion of the computed tomography (CT) number to electron density is one of the main processes that determine the accuracy of patient dose calculations in radiotherapy treatment planning. However, the CT number and electron density of tissues cannot be generally interrelated via a simple one-to-one correspondence because the CT number depends on the effective atomic number as well as the electron density. The purpose of this study is to present a simple conversion from the energy-subtracted CT number ({Delta}HU) by means of dual-energy CT (DECT) to the relative electron density ({rho}{sub e}) via a single linear relationship. Methods: The {Delta}HU-{rho}{sub e} conversion method was demonstrated by performing analytical DECT image simulations that were intended to imitate a second-generation dual-source CT (DSCT) scanner with an additional tin filtration for the high-kV tube. The {Delta}HU-{rho}{sub e} calibration line was obtained from the image simulation with a 33 cm-diameter electron density calibration phantom equipped with 16 inserts including polytetrafluoroethylene, polyvinyl chloride, and aluminum; the elemental compositions of these three inserts were quite different to those of body tissues. The {Delta}HU-{rho}{sub e} conversion method was also applied to previously published experimental CT data, which were measured using two different CT scanners, to validate the clinical feasibility of the present approach. In addition, the effect of object size on {rho}{sub e}-calibrated images was investigated by image simulations using a 25 cm-diameter virtual phantom for two different filtrations: with and without the tin filter for the high-kV tube. Results: The simulated {Delta}HU-{rho}{sub e} plot exhibited a predictable linear relationship over a wide range of {rho}{sub e} from 0.00 (air) to 2.35 (aluminum). Resultant values of the coefficient of determination, slope, and intercept of the linear function fitted to the data were close to those

  16. Maximum wind energy extraction strategies using power electronic converters

    NASA Astrophysics Data System (ADS)

    Wang, Quincy Qing

    2003-10-01

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

  17. Optimisation Of a Magnetostrictive Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Mundon, T. R.; Nair, B.

    2014-12-01

    Oscilla Power, Inc. (OPI) is developing a patented magnetostrictive wave energy converter aimed at reducing the cost of grid-scale electricity from ocean waves. Designed to operate cost-effectively across a wide range of wave conditions, this will be the first use of reverse magnetostriction for large-scale energy production. The device architecture is a straightforward two-body, point absorbing system that has been studied at length by various researchers. A large surface float is anchored to a submerged heave (reaction) plate by multiple taut tethers that are largely made up of discrete, robust power takeoff modules that house the magnetostrictive generators. The unique generators developed by OPI utilize the phenomenon of reverse magnetostriction, which through the application of load to a specific low cost alloy, can generate significant magnetic flux changes, and thus create power through electromagnetic induction. Unlike traditional generators, the mode of operation is low-displacement, high-force, high damping which in combination with the specific multi-tether configuration creates some unique effects and interesting optimization challenges. Using an empirical approach with a combination of numerical tools, such as ORCAFLEX, and physical models, we investigated the properties and sensitivities of this system arrangement, including various heave plate geometries, with the overall goal of identifying the mass and hydrodynamic parameters required for optimum performance. Furthermore, through a detailed physical model test program at the University of New Hampshire, we were able to study in more detail how the heave plate geometry affects the drag and added mass coefficients. In presenting this work we will discuss how alternate geometries could be used to optimize the hydrodynamic parameters of the heave plate, allowing maximum inertial forces in operational conditions, while simultaneously minimizing the forces generated in extreme waves. This presentation

  18. Combination solar photovoltaic heat engine energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  19. Strained quantum well photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Freundlich, Alexandre (Inventor); Renaud, Philippe (Inventor); Vilela, Mauro Francisco (Inventor); Bensaoula, Abdelhak (Inventor)

    1998-01-01

    An indium phosphide photovoltaic cell is provided where one or more quantum wells are introduced between the conventional p-conductivity and n-conductivity indium phosphide layer. The approach allows the cell to convert the light over a wider range of wavelengths than a conventional single junction cell and in particular convert efficiently transparency losses of the indium phosphide conventional cell. The approach hence may be used to increase the cell current output. A method of fabrication of photovoltaic devices is provided where ternary InAsP and InGaAs alloys are used as well material in the quantum well region and results in an increase of the cell current output.

  20. Mathematical modeling of a photovoltaic-laser energy converter for iodine laser radiation

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Heinbockel, John H.

    1987-01-01

    Space-based laser power systems will require converters to change laser radiation into electricity. Vertical junction photovoltaic converters are promising devices for this use. A promising laser for the laser power station is the t-C4F9I laser which emits radiation at a wavelength of 1.315 microns. This paper describes the results of mathematical modeling of a photovoltaic-laser energy converter for use with this laser. The material for this photovoltaic converter is Ga(53)In(47)As which has a bandgap energy of 0.94 eV, slightly below the energy of the laser photons (0.943 eV). Results of a study optimizing the converter parameters are presented. Calculated efficiency for a 1000 vertical junction converter is 42.5 percent at a power density of 1 x 10 to the 3d power w/sq cm.

  1. Low Head, Vortex Induced Vibrations River Energy Converter

    SciTech Connect

    Bernitsas, Michael B.; Dritz, Tad

    2006-06-30

    Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) is a novel, demonstrated approach to extracting energy from water currents. This invention is based on a phenomenon called Vortex Induced Vibrations (VIV), which was first observed by Leonardo da Vinci in 1504AD. He called it ‘Aeolian Tones.’ For decades, engineers have attempted to prevent this type of vibration from damaging structures, such as offshore platforms, nuclear fuel rods, cables, buildings, and bridges. The underlying concept of the VIVACE Converter is the following: Strengthen rather than spoil vortex shedding; enhance rather than suppress VIV; harness rather than mitigate VIV energy. By maximizing and utilizing this unique phenomenon, VIVACE takes this “problem” and successfully transforms it into a valuable resource for mankind.

  2. Converting Sunlight to Mechanical Energy: A Polymer Example of Entropy.

    ERIC Educational Resources Information Center

    Mathias, Lon J.

    1987-01-01

    This experiment/demonstration provides elementary through high school science students with hands-on experience with polymer entropy. Construction of a simple machine for converting light into mechanical energy is described. (RH)

  3. Laser-to-electricity energy converter for short wavelengths

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.; Yeh, Y. C. M.

    1975-01-01

    Short-wavelength energy converter can be made using Schottky barrier structure. It has wider band gap than p-n junction silicon semiconductors, and thus it has improved response at wavelengths down to and including ultraviolet region.

  4. Converting acoustic energy into useful other energy forms

    DOEpatents

    Putterman, Seth J.; Barber, Bradley Paul; Hiller, Robert Anthony; Lofstedt, Ritva Maire Johanna

    1997-01-01

    Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

  5. Moving core beam energy absorber and converter

    DOEpatents

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  6. Combustor design tool for a gas fired thermophotovoltaic energy converter

    SciTech Connect

    Lindler, K.W.; Harper, M.J.

    1995-07-01

    Recently, there has been a renewed interest in thermophotovoltaic (TPV) energy conversion. A TPV device converts radiant energy from a high temperature incandescent emitter directly into electricity by photovoltaic cells. The current Department of Energy sponsored research involves the design, construction and demonstration of a prototype TPV converter that uses a hydrocarbon fuel (such as natural gas) as the energy source. As the photovoltaic cells are designed to efficiently convert radiant energy at a prescribed wavelength, it is important that the temperature of the emitter be nearly constant over its entire surface. The US Naval Academy has been tasked with the development of a small emitter (with a high emissivity) that can be maintained at 1,756 K (2,700 F). This paper describes the computer spreadsheet model that was developed as a tool to be used for the design of the high temperature emitter.

  7. Combustor design tool for a gas fired thermophotovoltaic energy converter

    SciTech Connect

    Lindler, K.W.; Harper, M.J.

    1995-12-31

    Recently, there has been a renewed interest in thermophotovoltaic (TPV) energy conversion. A TPV device converts radiant energy from a high temperature incandescent emitter directly into electricity by photovoltaic cells. The current Department of Energy sponsored research involves the design, construction and demonstration of a prototype TPV converter that uses a hydrocarbon fuel (such as natural gas) as the energy source. As the photovoltaic cells are designed to efficiently convert radiant energy at a prescribed wavelength, it is important that the temperature of the emitter be nearly constant over its entire surface. The U. S. Naval Academy has been tasked with the development of a small emitter (with a high emissivity) that can be maintained at 1756 K (2700 F). This paper describes the computer spreadsheet model that was developed as a tool to be used for the design of the high temperature emitter.

  8. Energy Extraction from a Slider-Crank Wave Energy Converter under Irregular Wave Conditions

    SciTech Connect

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-10-19

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  9. Development of a wind converter and investigation of its operational function. Part 1: Technical description of the wind energy converter

    NASA Astrophysics Data System (ADS)

    Molly, J. P.; Steinheber, R.

    1982-11-01

    A 10 kW wind energy converter was developed by using as far possible standard serial production parts. The design criteria and the description of the essential machinery components of the MODA 10 wind energy converter are discussed. For some special load cases the safety calculation of the important components is shown. The blade control system which qualified for small wind energy converters, is explained. Weight and cost of the MODA 10 are considered.

  10. Converting energy to medical progress [nuclear medicine

    SciTech Connect

    2001-04-01

    For over 50 years the Office of Biological and Environmental Research (BER) of the United States Department of Energy (DOE) has been investing to advance environmental and biomedical knowledge connected to energy. The BER Medical Sciences program fosters research to develop beneficial applications of nuclear technologies for medical diagnosis and treatment of many diseases. Today, nuclear medicine helps millions of patients annually in the United States. Nearly every nuclear medicine scan or test used today was made possible by past BER-funded research on radiotracers, radiation detection devices, gamma cameras, PET and SPECT scanners, and computer science. The heart of biological research within BER has always been the pursuit of improved human health. The nuclear medicine of tomorrow will depend greatly on today's BER-supported research, particularly in the discovery of radiopharmaceuticals that seek specific molecular and genetic targets, the design of advanced scanners needed to create meaningful images with these future radiotracers, and the promise of new radiopharmaceutical treatments for cancers and genetic diseases.

  11. Converting Energy to Medical Progress [Nuclear Medicine

    DOE R&D Accomplishments Database

    2001-04-01

    For over 50 years the Office of Biological and Environmental Research (BER) of the United States Department of Energy (DOE) has been investing to advance environmental and biomedical knowledge connected to energy. The BER Medical Sciences program fosters research to develop beneficial applications of nuclear technologies for medical diagnosis and treatment of many diseases. Today, nuclear medicine helps millions of patients annually in the United States. Nearly every nuclear medicine scan or test used today was made possible by past BER-funded research on radiotracers, radiation detection devices, gamma cameras, PET and SPECT scanners, and computer science. The heart of biological research within BER has always been the pursuit of improved human health. The nuclear medicine of tomorrow will depend greatly on today's BER-supported research, particularly in the discovery of radiopharmaceuticals that seek specific molecular and genetic targets, the design of advanced scanners needed to create meaningful images with these future radiotracers, and the promise of new radiopharmaceutical treatments for cancers and genetic diseases.

  12. Solid state transport-based thermoelectric converter

    DOEpatents

    Hu, Zhiyu

    2010-04-13

    A solid state thermoelectric converter includes a thermally insulating separator layer, a semiconducting collector and an electron emitter. The electron emitter comprises a metal nanoparticle layer or plurality of metal nanocatalyst particles disposed on one side of said separator layer. A first electrically conductive lead is electrically coupled to the electron emitter. The collector layer is disposed on the other side of the separator layer, wherein the thickness of the separator layer is less than 1 .mu.m. A second conductive lead is electrically coupled to the collector layer.

  13. Rectenna that converts infrared radiation to electrical energy

    DOEpatents

    Davids, Paul; Peters, David W.

    2016-09-06

    Technologies pertaining to converting infrared (IR) radiation to DC energy are described herein. In a general embodiment, a rectenna comprises a conductive layer. A thin insulator layer is formed on the conductive layer, and a nanoantenna is formed on the thin insulator layer. The thin insulator layer acts as a tunnel junction of a tunnel diode.

  14. First-order irreversible thermodynamic approach to a nonsteady RLC circuit as an energy converter

    NASA Astrophysics Data System (ADS)

    Valencia, G.; Arias, L. A.

    2015-01-01

    In this work we show a RLC-circuit as energy converter within the context of first-order irreversible thermodynamics (FOIT). For our analysis, we propose an isothermic model with transient elements and passive elements. With the help of the dynamic equations, the Kirchhoff equations, we found the generalized fluxes and forces of the circuit, the equation system shows symmetry of the cross terms, this property is characteristic of the steady state linear systems, but in this case phenomenological coefficients are function of time. Then, we can use these relations, similar to the linear Onsager relations, to construct the characteristic functions of the RLC energy converter: the power output, efficiency, dissipation and ecological function, and study its energetic performance. The study of performance of the converter is based on two parameters, the coupling parameter and the "forces ratio" parameter, in this case as functions of time. We find that the behavior of the non-steady state converter is similar to the behavior of steady state energy converter. We will explain the linear and symmetric behavior of the converter in the frequencies space rather than in the time space. Finally, we establish optimal operation regimes of economic degree of coupling for this energy converter.

  15. Stochastic Control of Inertial Sea Wave Energy Converter

    PubMed Central

    Mattiazzo, Giuliana; Giorcelli, Ermanno

    2015-01-01

    The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks. PMID:25874267

  16. Polarization converters based on axially symmetric twisted nematic liquid crystal.

    PubMed

    Ko, Shih-Wei; Ting, Chi-Lun; Fuh, Andy Y-G; Lin, Tsung-Hsien

    2010-02-15

    An axially symmetric twisted nematic liquid crystal (ASTNLC) device, based on axially symmetric photoalignment, was demonstrated. Such an ASTNLC device can convert axial (azimuthal) to azimuthal (axial) polarization. The optical properties of the ASTNLC device are analyzed and found to agree with simulation results. The ASTNLC device with a specific device can be adopted as an arbitrary axial symmetric polarization converter or waveplate for axially, azimuthally or vertically polarized light. A design for converting linear polarized light to axially symmetric circular polarized light is also demonstrated. PMID:20389369

  17. Ultrathin flexible terahertz polarization converter based on metasurfaces.

    PubMed

    Mo, Weicheng; Wei, Xuli; Wang, Kejia; Li, Yao; Liu, Jinsong

    2016-06-13

    We present a method to design and fabricate a kind of converters based on flexible metasurfaces which can change the polarization state of an incident terahertz beam. The metasurface consists of a two-dimensional array of rectangular metallic antennas that can abruptly change the phase of the incoming terahertz beam. Experimentally demonstrated half-wave plates generate 0.1 THz beam with a π/2 polarization rotation. By slightly changing the structure of the converter, an elliptically or circularly polarized beam is expected to be obtained. These flexible terahertz converters may have many potential applications in terahertz technology. PMID:27410377

  18. Design and analysis of VCSEL based twodimension wavelength converter.

    PubMed

    Liu, H; Shum, P; Kao, M

    2003-07-14

    A novel two-dimensional vertical cavity surface emission laser (VCSEL) based wavelength converter is proposed. We developed a twodimensional transmission line laser model (TLLM) to analyze the proposed wavelength converter. This model takes into account Bragg reflectors by using the modified connecting matrix. Therefore, accurate and efficient modeling of the VCSEL structure is achieved. Extinction ratio of the output signal is investigated by considering input signal power, wavelength, facet reflectivity and cavity diameter. PMID:19466044

  19. Method for converting one form of energy into another form of energy

    SciTech Connect

    Anno, J.N.; Fawcett, S.L.

    1983-05-31

    Method for converting one form of energy into another form of energy by isobarically heating a gas, adiabatically expanding the gas while converting the heat energy of the gas into the kinetic energy of a moving body, converting the kinetic energy of the moving body into another form of energy, and approximately isothermally compressing the gas to a higher pressure. Improved efficiency is achieved by virtue of the fact that this system employs approximately isothermal compression, which is preferably achieved by injecting liquid into an adiabatically-expanded gas, thereby effecting a thermodynamic cycle which more closely approximates the efficiency of a carnot cycle.

  20. Trimode Power Converter optimizes PV, diesel and battery energy sources

    SciTech Connect

    O`Sullivan, G.; Bonn, R.; Bower, W.

    1994-07-01

    Conservatively, there are 100,000 localities in the world waiting for the benefits that electricity can provide, and many of these are in climates where sunshine is plentiful. With these locations in mind a prototype 30 kW hybrid system has been assembled at Sandia to prove the reliability and economics of photovoltaic, diesel and battery energy sources managed by an autonomous power converter. In the Trimode Power Converter the same power parts, four IGBT`s with an isolation transformer and filter components, serve as rectifier and charger to charge the battery from the diesel; as a stand-alone inverter to convert PV and battery energy to AC; and, as a parallel inverter with the diesel-generator to accommodate loads larger than the rating of the diesel. Whenever the diesel is supplying the load, an algorithm assures that the diesel is running at maximum efficiency by regulating the battery charger operating point. Given the profile of anticipated solar energy, the cost of transporting diesel fuel to a remote location and a five year projection of load demand, a method to size the PV array, battery and diesel for least cost is developed.

  1. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    NASA Astrophysics Data System (ADS)

    Wu, Jia-Liang; Lin, Bao-Qin; Da, Xin-Yu

    2016-08-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x- or y-polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471387, 61271250, and 61571460).

  2. Design of Energy Storage Reactors for Dc-To-Dc Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.

    1975-01-01

    Two methodical approaches to the design of energy-storage reactors for a group of widely used dc-to-dc converters are presented. One of these approaches is based on a steady-state time-domain analysis of piecewise-linearized circuit models of the converters, while the other approach is based on an analysis of the same circuit models, but from an energy point of view. The design procedure developed from the first approach includes a search through a stored data file of magnetic core characteristics and results in a list of usable reactor designs which meet a particular converter's requirements. Because of the complexity of this procedure, a digital computer usually is used to implement the design algorithm. The second approach, based on a study of the storage and transfer of energy in the magnetic reactors, leads to a straightforward design procedure which can be implemented with hand calculations. An equation to determine the lower-bound volume of workable cores for given converter design specifications is derived. Using this computer lower-bound volume, a comparative evaluation of various converter configurations is presented.

  3. Model predictive control of bidirectional isolated DC-DC converter for energy conversion system

    NASA Astrophysics Data System (ADS)

    Akter, Parvez; Uddin, Muslem; Mekhilef, Saad; Tan, Nadia Mei Lin; Akagi, Hirofumi

    2015-08-01

    Model predictive control (MPC) is a powerful and emerging control algorithm in the field of power converters and energy conversion systems. This paper proposes a model predictive algorithm to control the power flow between the high-voltage and low-voltage DC buses of a bidirectional isolated full-bridge DC-DC converter. The predictive control algorithm utilises the discrete nature of the power converters and predicts the future nature of the system, which are compared with the references to calculate the cost function. The switching state that minimises the cost function is selected for firing the converter in the next sampling time period. The proposed MPC bidirectional DC-DC converter is simulated with MATLAB/Simulink and further verified with a 2.5 kW experimental configuration. Both the simulation and experimental results confirm that the proposed MPC algorithm of the DC-DC converter reduces reactive power by avoiding the phase shift between primary and secondary sides of the high-frequency transformer and allow power transfer with unity power factor. Finally, an efficiency comparison is performed between the MPC and dual-phase-shift-based pulse-width modulation controlled DC-DC converter which ensures the effectiveness of the MPC controller.

  4. Electro-mechanical energy conversion system having a permanent magnet machine with stator, resonant transfer link and energy converter controls

    DOEpatents

    Skeist, S. Merrill; Baker, Richard H.

    2006-01-10

    An electro-mechanical energy conversion system coupled between an energy source and an energy load comprising an energy converter device including a permanent magnet induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer to control the flow of power or energy through the permanent magnetic induction machine.

  5. The TELEC - A plasma type of direct energy converter. [Thermo-Electronic Laser Energy Converter for electric power generation

    NASA Technical Reports Server (NTRS)

    Britt, E. J.

    1978-01-01

    The Thermo-Electronic Laser Energy Converter (TELEC) is a high-power density plasma device designed to convert a 10.6-micron CO2 laser beam into electric power. Electromagnetic radiation is absorbed in plasma electrons, creating a high-electron temperature. Energetic electrons diffuse from the plasma and strike two electrodes having different areas. The larger electrode collects more electrons and there is a net transport of current. An electromagnetic field is generated in the external circuit. A computer program has been designed to analyze TELEC performance allowing parametric variation for optimization. Values are presented for TELEC performance as a function of cesium pressure and for current density and efficiency as a function of output voltage. Efficiency is shown to increase with pressure, reaching a maximum over 45%.

  6. Reference Model 6 (RM6): Oscillating Wave Energy Converter.

    SciTech Connect

    Bull, Diana L; Smith, Chris; Jenne, Dale Scott; Jacob, Paul; Copping, Andrea; Willits, Steve; Fontaine, Arnold; Brefort, Dorian; Gordon, Margaret Ellen; Copeland, Robert; Jepsen, Richard Alan

    2014-10-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter reference model design in a complementary manner to Reference Models 1-4 contained in the above report. In this report, a conceptual design for an Oscillating Water Column Wave Energy Converter (WEC) device appropriate for the modeled reference resource site was identified, and a detailed backward bent duct buoy (BBDB) device design was developed using a combination of numerical modeling tools and scaled physical models. Our team used the methodology in SAND2013-9040 for the economic analysis that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays, up to 100 devices. The methodology was applied to identify key cost drivers and to estimate levelized cost of energy (LCOE) for this RM6 Oscillating Water Column device in dollars per kilowatt-hour ($/kWh). Although many costs were difficult to estimate at this time due to the lack of operational experience, the main contribution of this work was to disseminate a detailed set of methodologies and models that allow for an initial cost analysis of this emerging technology. This project is sponsored by the U.S. Department of Energy's (DOE) Wind and Water Power Technologies Program Office (WWPTO), within the Office of Energy Efficiency & Renewable Energy (EERE). Sandia National Laboratories, the lead in this effort, collaborated with partners from National Laboratories, industry, and universities to design and test this reference model.

  7. Superconducting A/D converters based on Josephson binary counters

    NASA Astrophysics Data System (ADS)

    Kuo, Feng

    1991-03-01

    A/D converters (ADCs) based on Josephson binary counters are demonstrated in all-Nb technology. These A/D converters use a single SQUID as the flux quantizer front-end with a minimum quantization level equivalent to 2 micro-A of input current. A 10-b unidirectional ADC and a 5-b tracking ADC are reported. Both circuits have been tested at 1 MS/s sampling rate with very low power consumption. They also exhibit good linearity within the full dynamic range tested.

  8. Superconducting A/D converters based on Josephson binary counters

    SciTech Connect

    Kuo, F. )

    1991-03-01

    This paper demonstrates A/D converters based on Josephson binary counters in all-Nb technology. These A/D converters employ a single SQUID as the flux quantizer front-end with a minimum quantization level equivalent to 2 {mu}A of input current. A 10-bit unidirectional ADC and a 5-bit tracking ADC are reported. Both circuits have been tested at 1 MS/s sampling rate with very low power consumption. They also exhibit good linearity within the dull dynamic range tested.

  9. Quartz crystal microbalance based on passive frequency to voltage converter

    SciTech Connect

    Burda, Ioan; Tunyagi, Arthur

    2012-02-15

    In dynamics of evaporation or drying of microdrops from a solid surface, a faster and precise quartz crystal microbalance (QCM) is needed. The fast QCM based on frequency to voltage converter is an attractive and powerful tool in the investigation of the dynamic regime of evaporation to translate the frequency shift in terms of a continuous voltage change. The frequency shift monitoring in fast QCM applications is a real challenge for electronic processing interface. Originally developed as a frequency shift processing interface, this novel passive frequency to voltage converter can produce faster, stable, and accurate results in regard to the QCM sensor behavior. In this article, the concept and circuit of passive frequency to voltage converter will be explained followed by static and dynamic characterization. Experimental results of microdrops evaporation will be given.

  10. Heterobarrier for converting hot-phonon energy to electric potential

    NASA Astrophysics Data System (ADS)

    Shin, Seungha; Melnick, Corey; Kaviany, Massoud

    2013-02-01

    We show that hot phonons emitted in energy conversion or resistive processes can be converted to electric potential in heterobarrier structures. Using phonon and electron interaction kinetics and self-consistent ensemble Monte Carlo, we find the favorable conditions for unassisted absorption of hot phonons and design graded heterobarriers for their direct conversion into electric energy. Tandem barriers with nearly optical-phonon height allow for substantial potential gain without current loss. We find that 19% of hot phonons can be harvested with an optimized GaAs/AlxGa1-xAs barrier structure over a range of current and electron densities, thus enhancing the overall energy conversion efficiency and reducing waste heat.

  11. Thermophotovoltaic converters on indium arsenide-based compounds

    NASA Astrophysics Data System (ADS)

    Gevorkyan, V. A.; Aroutiounian, V. M.; Gambaryan, K. M.; Arakelyan, A. O.; Andreev, I. A.; Golubev, L. V.; Yakovlev, Yu. P.

    2007-03-01

    Thermophotovoltaic converters based on multicomponent solid solutions of III V compounds, specifically, InAsSbP/InAs heterostructures ( E g = 0.35 0.60 eV), that are intended for fabricating IR emitters heated to 1000 2000°C are studied. The use of such narrow-gap heterostructures makes it possible to advance the sensitivity of the elements into the long-wave range and utilize the thermal energy of low-temperature sources more efficiently. Fresh physical approaches to fabricating epitaxial quaternary InAs-based InAsSbP solid solutions with a low carrier concentration and heterostructures with sharp interfaces are presented. Quaternary InAsSbP solid solutions and other related heterostructures offer a number of advantages, such as the possibility of growing perfect structures lattice-matched with the substrate, stress-free interfaces, good electrical and photoelectrical properties (low dark currents and a high external quantum efficiency), and the possibility of flexibly controlling the energy gap by varying the composition of the solid solution. It is shown that InAsSbP films grown on an InAs substrate by liquid-phase epitaxy from supercooled liquid solution and liquid-phase electro-epitaxy with replenishment of liquid solution by growing layer components are uniform in composition and have a perfect crystal structure. Thermophotovolatic p-InAsSbP/ n-InAs diode-type heterostructures obtained by the above methods are found to have saturation dark currents close to theoretically predicted values and a wide range of spectral sensitivity, which makes them candidates for thermophotovoltaic elements.

  12. Real-time Ocean Wave Prediction for Optimal Performance of a Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Cavaglieri, Daniele; Bewley, Thomas

    2013-11-01

    In recent years, there has been a growing interest in renewable energy. Among all the available possibilities, wave energy conversion, due to the huge availability of energy that the ocean could provide, represents nowadays one of the most promising solutions. However, the efficiency of a wave energy converter for ocean wave energy harvesting is still far from making it competitive with more mature fields of renewable energy, such as solar and wind energy. One of the main problems is related to the inability to accurately predict the profile of oncoming waves approaching the wave energy converter. For this reason, we developed a new hybrid method for state estimation of nonlinear systems, which is based on a variational formulation of an ensemble smoother, combined with the formulation of the ensemble Kalman smoother. This method has been employed for the optimal forecasting of ocean waves via sensors placed on an array of wave energy converters. The coupled simulation of ocean waves and energy devices has been carried out leveraging a nonlinear High Order Spectral code.

  13. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    SciTech Connect

    Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.

    2015-01-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  14. 100kW Energy Transfer Multiplexer Power Converter Prototype Development Project

    SciTech Connect

    S. Merrill Skeist; Richard H. Baker; Anthony G.P. Marini; DOE Project Officer - Keith Bennett

    2006-03-21

    Project Final Report for "100kW Energy Transfer Multiplexer Power Converter Prototype Development Project" prepared under DOE grant number DE-FG36-03GO13138. This project relates to the further development and prototype construction/evaluation for the Energy Transfer Multiplexer (ETM) power converter topology concept. The ETM uses a series resonant link to transfer energy from any phase of a multiphase input to any phase of a multiphase output, converting any input voltage and frequency to any output voltage and frequency. The basic form of the ETM converter consists of an eight (8)-switch matrix (six phase power switches and two ground power switches) and a series L-C resonant circuit. Electronic control of the switches allows energy to be transferred in the proper amount from any phase to any other phase. Depending upon the final circuit application, the switches may be either SCRs or IGBTs. The inherent characteristics of the ETM converter include the following: Power processing in either direction (bidirectional); Large voltage gain without the need of low frequency magnetics; High efficiency independent of output load and frequency; Wide bandwidth with fast transient response and; Operation as a current source. The ETM is able to synthesize true sinusoidal waveforms with low harmonic distortions. For a low power PM wind generation system, the ETM has the following characteristics and advantages: It provides voltage gain without the need of low frequency magnetics (DC inductors) and; It has constant high efficiency independent of the load. The ETM converter can be implemented into a PM wind power system with smaller size, reduced weight and lower cost. As a result of our analyses, the ETM offers wind power generation technology for the reduction of the cost and size as well as the increase in performance of low power, low wind speed power generation. This project is the further theoretical/analytical exploration of the ETM converter concept in relationship to

  15. Adjustable wideband reflective converter based on cut-wire metasurface

    NASA Astrophysics Data System (ADS)

    Zhang, Linbo; Zhou, Peiheng; Chen, Haiyan; Lu, Haipeng; Xie, Jianliang; Deng, Longjiang

    2015-10-01

    We present the design, analysis, and measurement of a broadband reflective converter using a cut-wire (CW) metasurface. Based on the characteristics of LC resonances, the proposed reflective converter can rotate a linearly polarized (LP) wave into its cross-polarized wave at three resonance frequencies, or convert the LP wave to a circularly polarized (CP) wave at two other resonance frequencies. Furthermore, the broad-band properties of the polarization conversion can be sustained when the incident wave is a CP wave. The polarization states can be adjusted easily by changing the length and width of the CW. The measured results show that a polarization conversion ratio (PCR) over 85% can be achieved from 6.16 GHz to 16.56 GHz for both LP and CP incident waves. The origin of the polarization conversion is interpreted by the theory of microwave antennas, with equivalent impedance and electromagnetic (EM) field distributions. With its simple geometry and multiple broad frequency bands, the proposed converter has potential applications in the area of selective polarization control.

  16. Standing wave tube electro active polymer wave energy converter

    NASA Astrophysics Data System (ADS)

    Jean, Philippe; Wattez, Ambroise; Ardoise, Guillaume; Melis, C.; Van Kessel, R.; Fourmon, A.; Barrabino, E.; Heemskerk, J.; Queau, J. P.

    2012-04-01

    Over the past 4 years SBM has developed a revolutionary Wave Energy Converter (WEC): the S3. Floating under the ocean surface, the S3 amplifies pressure waves similarly to a Ruben's tube. Only made of elastomers, the system is entirely flexible, environmentally friendly and silent. Thanks to a multimodal resonant behavior, the S3 is capable of efficiently harvesting wave energy from a wide range of wave periods, naturally smoothing the irregularities of ocean wave amplitudes and periods. In the S3 system, Electro Active Polymer (EAP) generators are distributed along an elastomeric tube over several wave lengths, they convert wave induced deformations directly into electricity. The output is high voltage multiphase Direct Current with low ripple. Unlike other conventional WECs, the S3 requires no maintenance of moving parts. The conception and operating principle will eventually lead to a reduction of both CAPEX and OPEX. By integrating EAP generators into a small scale S3, SBM achieved a world first: direct conversion of wave energy in electricity with a moored flexible submerged EAP WEC in a wave tank test. Through an extensive testing program on large scale EAP generators, SBM identified challenges in scaling up to a utility grid device. French Government supports the consortium consisting of SBM, IFREMER and ECN in their efforts to deploy a full scale prototype at the SEMREV test center in France at the horizon 2014-2015. SBM will be seeking strategic as well as financial partners to unleash the true potentials of the S3 Standing Wave Tube Electro Active Polymer WEC.

  17. Solar-energy conversion by combined photovoltaic converters with CdTe and CuInSe{sub 2} base layers

    SciTech Connect

    Khrypunov, G. S. Sokol, E. I.; Yakimenko, Yu. I.; Meriuts, A. V.; Ivashuk, A. V.; Shelest, T. N.

    2014-12-15

    The possibility of the combined use of bifacial thin-film solar cells based on CdTe and frontal solar cells with a CuInSe{sub 2} base layer in tandem structures is experimentally confirmed. It is found that, for the use of bifacial solar cells based on cadmium telluride in a tandem structure, the optimal thickness of their base layer should be 1 μm. The gain in the efficiency of the tandem structure, compared with an individual CuInSe{sub 2}-based solar cell, is 1.8% in the case of series-connected solar cells and 1.3%, for parallel-connected.

  18. Surveying converter lining erosion state based on laser measurement technique

    NASA Astrophysics Data System (ADS)

    Li, Hongsheng; Shi, Tielin; Yang, Shuzi

    1998-08-01

    It is very important to survey the eroding state of the steelmaking converter lining real time so as to optimize technological process, extend converter durability and reduce steelmaking production costs. This paper gives one practical method based on the laser measure technique. It presents the basic principle of the measure technique. It presents the basic principle of the measure method, the composition of the measure system and the researches on key technological problems. The method is based on the technique of the laser range finding to net points on the surface of the surveyed converter lining, and the technology of angle finding to the laser beams. The angle signals would be used to help realizing the automatic scanning function also. The laser signals would be modulated and encoded. In the meantime, we would adopt the wavelet analysis and other filter algorithms, to denoise noisy data and extract useful information. And the main idea of some algorithms such as the net point measuring path planning and the measure device position optimal algorithm would also be given in order to improve the measure precision and real time property of the system.

  19. Tunable graphene-based dual-frequency cross polarization converters

    NASA Astrophysics Data System (ADS)

    Ding, Jun; Arigong, Bayaner; Ren, Han; Shao, Jin; Zhou, Mi; Lin, Yuankun; Zhang, Hualiang

    2015-03-01

    In this paper, we proposed a novel cross-polarization converter that simultaneously works at two frequencies in the reflection mode, which is constructed of an L-shape perforated graphene sheet printed on a dielectric spacer backed by a gold layer. For the normal incidence, the optical rotation at these two working frequencies originates from the simultaneous excitation of both eigenmodes characterized as the localized surface plasmon resonances. In addition, both working frequencies can be tuned within a large frequency range by varying the Fermi energy of the graphene, which opens up tremendous opportunities to develop voltage-controlled tunable devices at mid-IR frequencies.

  20. Modular DC-DC converter system for energy harvesting with EAPs

    NASA Astrophysics Data System (ADS)

    Eitzen, L.; Graf, C.; Maas, J.

    2013-04-01

    Energy harvesting with EAPs requires an energy-efficient power electronics providing a bidirectional energy transfer and operating voltages of up to several kilovolts. A possibility to achieve a high energy-efficiency for high voltage conversion is the use of a modular converter system consisting of several bidirectional converter modules, which are connected in series on the converter output side and in parallel at the input side. Since each converter stage provides only a part of the overall converter output voltage, the converter module output voltages can effectively be reduced by choosing the number of cascaded converter modules appropriately. This allows the use of standard semiconductor switches with superior electrical characteristics compared to high voltage semiconductors, enabling a high energy-efficiency and smaller passive components. Since EAP devices exhibit a mainly capacitive behavior and a limitation of the operating current is required for electrode protection, the utilized converter structure/topology has to be operated as a controllable current source on the lowest control level, which is achieved by operating the converter modules of the modular converter system with a subordinate closed-looped current control scheme. In order to avoid voltage unbalances among the single converter modules, a method for voltage balancing is presented. For validation, experimental results of a realized bidirectional flyback converter prototype are presented and discussed.

  1. Photonics-based tunable and broadband radio frequency converter

    NASA Astrophysics Data System (ADS)

    Borges, Ramon Maia; Mazzer, Daniel; Rufino Marins, Tiago Reis; Sodré, Arismar Cerqueira

    2016-03-01

    This paper is regarding the concept and development of a photonics-based tunable and broadband radio frequency converter (PBRC). It employs an external modulation technique to generate and reconfigure its output frequency, a digital circuit to manage the modulators' bias voltages, and an optical interface for connecting it to optical-wireless networks based on radio-over-fiber technology. The proposed optoelectronic device performs photonics-based upconversion and downconversion as a function of the local oscillator frequency and modulators' bias points. Experimental results demonstrate a radiofrequency (RF) carrier conversion with spectral purity over the frequency range from 750 MHz to 6.0 GHz, as well as the integration of the photonics-based converter with an optical backhaul based on a 1.5-km single-mode fiber from a geographically distributed optical network. Low phase noise and distortion absence illustrate its applicability for convergent and reconfigurable optical wireless communications. A potential application relies on the use of PBRC in convergent optical wireless networks to dynamically provide RF carriers as a function of the telecom operator demand and radio propagation environment.

  2. The APA Style Converter: a Web-based interface for converting articles to APA style for publication.

    PubMed

    Li, Ping; Cunningham, Krystal

    2005-05-01

    The APA Style Converter is a Web-based tool with which authors may prepare their articles in APA style according to the APA Publication Manual (5th ed.). The Converter provides a user-friendly interface that allows authors to copy and paste text and upload figures through the Web, and it automatically converts all texts, references, and figures to a structured article in APA style. The output is saved in PDF or RTF format, ready for either electronic submission or hardcopy printing. PMID:16171194

  3. Modeling and controller design of a wind energy conversion system including a matrix converter

    NASA Astrophysics Data System (ADS)

    Barakati, S. Masoud

    In this thesis, a grid-connected wind-energy converter system including a matrix converter is proposed. The matrix converter, as a power electronic converter, is used to interface the induction generator with the grid and control the wind turbine shaft speed. At a given wind velocity, the mechanical power available from a wind turbine is a function of its shaft speed. Through the matrix converter, the terminal voltage and frequency of the induction generator is controlled, based on a constant V/f strategy, to adjust the turbine shaft speed and accordingly, control the active power injected into the grid to track maximum power for all wind velocities. The power factor at the interface with the grid is also controlled by the matrix converter to either ensure purely active power injection into the grid for optimal utilization of the installed wind turbine capacity or assist in regulation of voltage at the point of connection. Furthermore, the reactive power requirements of the induction generator are satisfied by the matrix converter to avoid use of self-excitation capacitors. The thesis addresses two dynamic models: a comprehensive dynamic model for a matrix converter and an overall dynamical model for the proposed wind turbine system. The developed matrix converter dynamic model is valid for both steady-state and transient analyses, and includes all required functions, i.e., control of the output voltage, output frequency, and input displacement power factor. The model is in the qdo reference frame for the matrix converter input and output voltage and current fundamental components. The validity of this model is confirmed by comparing the results obtained from the developed model and a simplified fundamental-frequency equivalent circuit-based model. In developing the overall dynamic model of the proposed wind turbine system, individual models of the mechanical aerodynamic conversion, drive train, matrix converter, and squirrel-cage induction generator are developed

  4. A High Efficiency Boost Converter with MPPT Scheme for Low Voltage Thermoelectric Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Guan, Mingjie; Wang, Kunpeng; Zhu, Qingyuan; Liao, Wei-Hsin

    2016-07-01

    Using thermoelectric elements to harvest energy from heat has been of great interest during the last decade. This paper presents a direct current-direct current (DC-DC) boost converter with a maximum power point tracking (MPPT) scheme for low input voltage thermoelectric energy harvesting applications. Zero current switch technique is applied in the proposed MPPT scheme. Theoretical analysis on the converter circuits is explored to derive the equations for parameters needed in the design of the boost converter. Simulations and experiments are carried out to verify the theoretical analysis and equations. A prototype of the designed converter is built using discrete components and a low-power microcontroller. The results show that the designed converter can achieve a high efficiency at low input voltage. The experimental efficiency of the designed converter is compared with a commercial converter solution. It is shown that the designed converter has a higher efficiency than the commercial solution in the considered voltage range.

  5. Improvement of up-converting phosphor technology-based biosensor

    NASA Astrophysics Data System (ADS)

    Xie, Chengke; Huang, Lihua; Zhang, Youbao; Guo, Xiaoxian; Qu, Jianfeng; Huang, Huijie

    2008-12-01

    A novel biosensor based on up-converting phosphor technology (UPT) was developed several years ago. It is a kind of optical biosensor using up-converting phosphor (UCP) particles as the biological marker. From then on, some improvements have been made for this UPT-based biosensor. The primary aspects of the improvement lie in the control system. On one hand, the hardware of the control system has been optimized, including replacing two single chip microcomputers (SCM) with only one, the optimal design of the keyboard interface circuit and the liquid crystal module (LCM) control circuit et al.. These result in lower power consumption and higher reliability. On the other hand, a novel signal processing algorithm is proposed in this paper, which can improve the automation and operating simplicity of the UPT-based biosensor. It has proved to have high sensitivity (~ng/ml), high stability and good repeatability (CV<5%), which is better than the former system. It can meet the need of some various applications such as rapid immunoassay, chemical and biological detection and so on.

  6. Optimal geometry of an axisymmetric wave energy converter

    NASA Astrophysics Data System (ADS)

    Edwards, Emma; Yue, Dick K. P.; Vortical Flow Research Laboratory Team

    2015-11-01

    There have been a number of theoretical, experimental and pilot-scale studies on wave energy converters with varying shapes and designs, but due to the complex nature of wave-body hydrodynamics, as yet there is not one single three-dimensional shape that is agreed-upon to be optimal for wave power extraction. Our objective is to determine the optimal geometry to maximize power uptake over a spectrum of incident waves. As an initial investigation, we consider an axisymmetric floating wave power extraction device operating in heave. We assume linear wave conditions. The body geometry is described by smooth polynomial basis functions and is allowed to be completely general, subject to simple constraints. We consider a linear power uptake with a fixed damping coefficient (which could be optimized). For each frequency in the spectrum, hydrodynamic coefficients are calculated using a linear frequency-domain panel method. Then, for a specific incident wave spectrum, maximal extractable power is integrated over the entire spectrum. We will discuss the optimal geometry and associated maximum power for different geometrical constraints and wave conditions.

  7. Control of modular multilevel converters for grid integration of full-scale wind energy conversion systems

    NASA Astrophysics Data System (ADS)

    Debnath, Suman

    The growing demand for wind power generation has pushed the capacity of wind turbines towards MW power levels. Higher capacity of the wind turbines necessitates operation of the generators and power electronic conversion systems at higher voltage/power levels. The power electronic conversion system of a wind energy conversion system (WECS) needs to meet the stringent requirements in terms of reliability, efficiency, scalability and ease of maintenance, power quality, and dv/dt stress on the generator/transformer. Although the multilevel converters including the neutral point clamped (NPC) converter and the active NPC converter meet most of the requirements, they fall short in reliability and scalability. Motivated by modularity/scalability feature of the modular multilevel converter (MMC), this research is to enable the MMC to meet all of the stringent requirements of the WECS by addressing their unique control challenges. This research presents systematic modeling and control of the MMC to enable it to be a potential converter topology for grid integration of full-scale WECSs. Based on the developed models, appropriate control systems for control of circulating current and capacitor voltages under fixed- and variable-frequency operations are proposed. Using the developed MMC models, a gradient-based cosimulation algorithm to optimize the gains of the developed control systems, is proposed. Performance/effectiveness of the developed models and the proposed control systems for the back-to-back MMC-based WECS are evaluated/verified based on simulations studies in the PSCAD/EMTDC software environment and experimental case studies on a laboratory-scale hardware prototype.

  8. Bifurcation analysis of a Lyapunov-based controlled boost converter

    NASA Astrophysics Data System (ADS)

    Spinetti-Rivera, Mario; Olm, Josep M.; Biel, Domingo; Fossas, Enric

    2013-11-01

    Lyapunov-based controlled boost converters have a unique equilibrium point, which is globally asymptotically stable, for known resistive loads. This article investigates the dynamic behaviors that appear in the system when the nominal load differs from the actual one and no action is taken by the controller to compensate for the mismatch. Exploiting the fact that the closed-loop system is, in fact, planar and quadratic, one may provide not only local but also global stability results: specifically, it is proved that the number of equilibria of the converter may grow up to three and that, in any case, the system trajectories are always bounded, i.e. it is a bounded quadratic system. The possible phase portraits of the closed-loop system are also characterized in terms of the selected bifurcation parameters, namely, the actual load value and the gain of the control law. Accordingly, the analysis allows the numerical illustration of many bifurcation phenomena that appear in bounded quadratic systems through a physical example borrowed from power electronics.

  9. Experimental studies and computer simulation of the control of energy transfer using inductor-converter bridges

    SciTech Connect

    Hirano, M.; Kustom, R.L.

    1984-03-01

    An inductor-converter bridge (ICB) is a solid state DC-AC-DC power converter system for bidirectional, controllable, energy transfer between two coils. The ICB is suitable for supplying large pulsed power to such magnets as the superconducting equilibrium field coil of the proposed tokamak power reactors from another superconducting energy storage coil.

  10. Design and Analysis for a Floating Oscillating Surge Wave Energy Converter: Preprint

    SciTech Connect

    Yu, Y. H.; Li, Y.; Hallett, K.; Hotimsky, C.

    2014-03-01

    This paper presents a recent study on the design and analysis of an oscillating surge wave energy converter. A successful wave energy conversion design requires the balance between the design performance and cost. The cost of energy is often used as the metric to judge the design of the wave energy conversion system. It is often determined based on the device power performance, the cost for manufacturing, deployment, operation and maintenance, as well as the effort to ensure the environmental compliance. The objective of this study is to demonstrate the importance of a cost driven design strategy and how it can affect a WEC design. Three oscillating surge wave energy converter (OSWEC) designs were used as the example. The power generation performance of the design was modeled using a time-domain numerical simulation tool, and the mass properties of the design were determined based on a simple structure analysis. The results of those power performance simulations, the structure analysis and a simple economic assessment were then used to determine the cost-efficiency of selected OSWEC designs. Finally, a discussion on the environmental barrier, integrated design strategy and the key areas that need further investigation is also presented.

  11. Mode converters based on cascaded long-period waveguide gratings.

    PubMed

    Jin, Wei; Chiang, Kin Seng

    2016-07-01

    We propose a mode-conversion platform based on cascaded long-period waveguide gratings. We demonstrate two specific devices by cascading a surface-corrugated grating and a sidewall-corrugated grating. One device allows conversion among the LP01, LP11b, and LP11a modes in a cyclic manner. The maximum conversion efficiency of a typical experimental device fabricated with polymer materials is about 94% at 1540 nm. The other device allows conversion between the LP01 and LP21a modes. The maximum conversion efficiency of a typical experimental device is estimated to be higher than 90% at 1550 nm. The performance of both devices is polarization-insensitive. The proposed platform could be developed into various mode converters for mode-division-multiplexing systems and other mode-sensitive applications. PMID:27367119

  12. Solar energy converter employing a fluorescent wavelength shifter

    SciTech Connect

    Garlick, G.F.J.

    1986-04-22

    A solar converter is described which consists of: (a) a zinc selenide fluorescent wavelength shifter including a fluorescent zinc selenide substrate having anti-reflecting coatings on opposite sides thereof and operative to convert predetermined wavelengths of solar radiation to radiation of different wavelengths for transmission to an adjacent solar cell, the fluorescent wavelength shifter having a response spectra extending between about 0.3 and 0.47 micrometers wavelength; (b) a gallium arsenide or aluminum gallium arsenide solar cell having a pn junction therein and an anti-reflective coating on one surface and further having a response spectra extending from approximately 0.47 micrometers to approximately 0.9 micrometers and operative to convert sunlight radiation of these wavelengths to output power; and (c) means for adhesively bonding one of the anti-reflectingly coated sides of the fluorescent wavelength shifter to the anti-reflective coating of the solar cell and for simultaneously providing good optical matching and transparency between these anti-reflecting coatings, whereby the pn junction of the solar cell converts radiation wavelengths within the fluorescence spectrum of the wavelength shifter to useful output power and thereby enhances and optimizes the solar conversion efficiency of the solar converter.

  13. Energy-efficient C-dump converters for switched reluctance motors

    SciTech Connect

    Mir, S.; Husain, I.; Elbuluk, M.E.

    1997-09-01

    Two energy-efficient converter topologies, derived from the conventional C-dump converter, are proposed for switched reluctance motor (SRM) drives. The proposed topologies overcome the limitations of the conventional C-dump converter, and could reduce the overall cost of the SRM drive. The voltage ratings of the dump capacitor and some of the switching devices in the proposed converters are reduced to the supply voltage (V{sub dc}) level compared to twice the supply voltage (2V{sub dc}) in the conventional C-dump converter. Also, the size of the dump inductor is considerably reduced. The converters have simple control requirements, and allow the motor phase current to freewheel during chopping mode. Simulation and experimental results of the converters are presented and discussed.

  14. Theoretical studies on performance evaluation of solar thermoelectronic energy converter with graphene emitter

    NASA Astrophysics Data System (ADS)

    Olawole, Olukunle; de, Dilip

    In this paper we consider detailed energy dynamics of solar thermoelectronic energy converter using graphene as the emitter. The emitter is heated by solar energy concentrated by a parabolic mirror concentrator. We study the performance evaluation of the energy conversion using temperature dependent work function of graphene and model the space charge problem by introducing a factor in the emitter and collector current densities. We present computations on power output and efficiency as function of solar insolation, height of emitter from the base of the mirror, reflection coefficient of the mirror, temperature and work function of collector. Effect of molecular doping on the performance of the graphene solar tech is also discussed. Please schedule our papers so that they are well separated in time for presentations.

  15. Magnetorheological converters

    SciTech Connect

    Zal'tsgendler, E.A.; Kolomentsev, A.V.; Kordonskii, V.I.; Madorskii, L.S.

    1986-04-01

    The authors study the problems of constructing an electrohydraulic converter functioning based on the magnetoheological effect: the magnetorheological throttle (MR throttle). Requirements are listed that must be taken into account in developing the MR throttle. The paper attempts to calculate the flow-rate characteristics of the MR throttle. The rheological equation which describes sufficiently the mechanical properties of the magnetoheological suspensions is presented. The paper examines the calculation of the magnetic inductor for the example of a toroidal core with a gap, which simultaneously functions as the slot throttling channel. The use of the designs described enabled the development of bridge converters, which have a flat amplitude-frequency characteristic in the range 200-250 Hz and which have good energy indicators. Typical experimental logarithmic amplitude-frequency and phase-frequency characteristics of a bridge converter are shown.

  16. A tapped-inductor buck-boost converter for a multi-DEAP generator energy harvesting system

    NASA Astrophysics Data System (ADS)

    Dimopoulos, Emmanouil; Munk-Nielsen, Stig

    2014-03-01

    Interest on Dielectric ElectroActive Polymer (DEAP) generators has aroused among scientists in recent years, due to the former ones' documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under high step-up and high step-down voltage conversion ratios, accompanied by low-average but relatively high-peak currents, imposes great challenges on the design of the employed power electronic converter. On top of that, the shortage of commercially-available, high-efficient, high-voltage, low-power semiconductor devices limits the effective operational range of the power electronic converter. In this paper, a bidirectional tapped-inductor buck-boost converter is proposed, addressing high- efficient high step-up and high step-down voltage conversion ratios, for energy harvesting applications based on DEAP generators. The effective operational range of the converter is extended, by replacing its high-side switch with a string of three serialized MOSFETs, to accommodate the need for high-efficient high-voltage operation. Experiments conducted on a single DEAP generator - part of a quadruple DEAP generator energy harvesting system with all elements installed sequentially in the same circular disk with a 90° phase shift - validate the applicability of the proposed converter, demonstrating energy harvesting of 0.26 J, at 0.5 Hz and 60% delta- strain; characterized by an energy density of 1.25 J per kg of active material.

  17. Why Flavins Are not Competitors of Chlorophyll in the Evolution of Biological Converters of Solar Energy

    PubMed Central

    Kritsky, Mikhail S.; Telegina, Taisiya A.; Vechtomova, Yulia L.; Buglak, Andrey A.

    2013-01-01

    Excited flavin molecules can photocatalyze reactions, leading to the accumulation of free energy in the products, and the data accumulated through biochemical experiments and by modeling prebiological processes suggest that flavins were available in the earliest stages of evolution. Furthermore, model experiments have shown that abiogenic flavin conjugated with a polyamino acid matrix, a pigment that photocatalyzes the phosphorylation of ADP to form ATP, could have been present in the prebiotic environment. Indeed, excited flavin molecules play key roles in many photoenzymes and regulatory photoreceptors, and the substantial structural differences between photoreceptor families indicate that evolution has repeatedly used flavins as chromophores for photoreceptor proteins. Some of these photoreceptors are equipped with a light-harvesting antenna, which transfers excitation energy to chemically reactive flavins in the reaction center. The sum of the available data suggests that evolution could have led to the formation of a flavin-based biological converter to convert light energy into energy in the form of ATP. PMID:23271372

  18. Why flavins are not competitors of chlorophyll in the evolution of biological converters of solar energy.

    PubMed

    Kritsky, Mikhail S; Telegina, Taisiya A; Vechtomova, Yulia L; Buglak, Andrey A

    2012-01-01

    Excited flavin molecules can photocatalyze reactions, leading to the accumulation of free energy in the products, and the data accumulated through biochemical experiments and by modeling prebiological processes suggest that flavins were available in the earliest stages of evolution. Furthermore, model experiments have shown that abiogenic flavin conjugated with a polyamino acid matrix, a pigment that photocatalyzes the phosphorylation of ADP to form ATP, could have been present in the prebiotic environment. Indeed, excited flavin molecules play key roles in many photoenzymes and regulatory photoreceptors, and the substantial structural differences between photoreceptor families indicate that evolution has repeatedly used flavins as chromophores for photoreceptor proteins. Some of these photoreceptors are equipped with a light-harvesting antenna, which transfers excitation energy to chemically reactive flavins in the reaction center. The sum of the available data suggests that evolution could have led to the formation of a flavin-based biological converter to convert light energy into energy in the form of ATP. PMID:23271372

  19. Full wave dc-to-dc converter using energy storage transformers

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1969-01-01

    Full wave dc-to-dc converter, for an ion thrustor, uses energy storage transformers to provide a method of dc-to-dc conversion and regulation. The converter has a high degree of physical simplicity, is lightweight and has high efficiency.

  20. Converting biomolecular modelling data based on an XML representation.

    PubMed

    Sun, Yudong; McKeever, Steve

    2008-01-01

    Biomolecular modelling has provided computational simulation based methods for investigating biological processes from quantum chemical to cellular levels. Modelling such microscopic processes requires atomic description of a biological system and conducts in fine timesteps. Consequently the simulations are extremely computationally demanding. To tackle this limitation, different biomolecular models have to be integrated in order to achieve high-performance simulations. The integration of diverse biomolecular models needs to convert molecular data between different data representations of different models. This data conversion is often non-trivial, requires extensive human input and is inevitably error prone. In this paper we present an automated data conversion method for biomolecular simulations between molecular dynamics and quantum mechanics/molecular mechanics models. Our approach is developed around an XML data representation called BioSimML (Biomolecular Simulation Markup Language). BioSimML provides a domain specific data representation for biomolecular modelling which can effciently support data interoperability between different biomolecular simulation models and data formats. PMID:20134068

  1. Output behavior based on writing occupancy in a photorefractive converter

    NASA Astrophysics Data System (ADS)

    Zerbino, Lia M.; Tebaldi, M.; Bolognini, N.

    2007-05-01

    In this paper, a one-dimensional image distribution is stored as modulation of birefringence in a BSO photorefractive crystal in an incoherent to coherent converter arrangement. The features of the read-out image under different write-in image magnifications of an input object are analyzed. In particular, characteristic parameters are introduced to assess the feasibility of an adequate recognition of the converted image. Experimental results under extinction configuration obtained by using intensity-normalized images are described.

  2. Push-pull converter with energy saving circuit for protecting switching transistors from peak power stress

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T. (Inventor)

    1981-01-01

    In a push-pull converter, switching transistors are protected from peak power stresses by a separate snubber circuit in parallel with each comprising a capacitor and an inductor in series, and a diode in parallel with the inductor. The diode is connected to conduct current of the same polarity as the base-emitter juction of the transistor so that energy stored in the capacitor while the transistor is switched off, to protect it against peak power stress, discharges through the inductor when the transistor is turned on, and after the capacitor is discharges through the diode. To return this energy to the power supply, or to utilize this energy in some external circuit, the inductor may be replaced by a transformer having its secondary winding connected to the power supply or to the external circuit.

  3. Thermophotovoltaic Converters Based on Poly-crystalline GaSb

    NASA Astrophysics Data System (ADS)

    Corregidor, V.; Vincent, J.; Algora, C.; Diéguez, E.

    2007-02-01

    In this work we present the development obtained on GaSb converters manufactured from GaSb polycrystals substrates since the last TPV Conference. As one of the main problem of these GaSb converters was the surface preparation, we present new surface treatments, besides higher structural quality of the ingots. The substrates were selected from polycrystalline ingots grown by vertical Bridgman technique. The electrical measurements show the n-type mobility values up to 1000 cm2ṡV-1ṡs-1. On these substrates, 4 mm2 thermophotovoltaic cells were manufactured and characterized by illuminated J-V curves and quantum efficiency techniques.

  4. Converting to DBMS 20 from Integrated Data Base Management System (IDMS)

    SciTech Connect

    Booher, J L

    1982-01-01

    A multi-project procurement system was developed for the Project Procurement and Control Department of the Planning and Control Division, Union Carbide, Oak Ridge Gaseous Diffusion Plant. This real-time system provides Union Carbide with information necessary for budgeting, scheduling, planning, and reporting procurement status to the Department of Energy. The system was initially designed and developed under IDMS on an IBM mainframe. A DEC 2020 was later purchased, and the procurement system was converted from IDMS to DBMS-20. Topics to be covered will include the procedures followed during the conversion, the differences and similarities of the two data base systems, and problems encountered during the conversion.

  5. Study of the properties of silicon-based semiconductor converters for betavoltaic cells

    SciTech Connect

    Polikarpov, M. A.; Yakimov, E. B.

    2015-06-15

    Silicon p-i-n diodes are studied in a scanning electron microscope under conditions simulating the β-radiation from a radioactive Ni{sup 63} source with an activity of 10 mCi/cm{sup 2}. The attainable parameters of β-voltaic cells with a source of this kind and a silicon-based converter of β-particle energy to electric current are estimated. It is shown that the power of elements of this kind can reach values of ∼10 nW/cm{sup 2} even for a cell with an area of one centimeter, which is rather close to the calculated value.

  6. Instrumentation for Monitoring around Marine Renewable Energy Converters: Workshop Final Report

    SciTech Connect

    Polagye, B. L.; Copping, A. E.; Brown-Saracino, J.; Suryan, R.; Kramer, S.; Smith, C.

    2014-01-14

    To better understand the state of instrumentation and capabilities for monitoring around marine energy converters, the U.S. Department of Energy directed Pacific Northwest National Laboratory and the Northwest National Marine Renewable Energy Center at the University of Washington to convene an invitation-only workshop of experts from around the world to address instrumentation needs.

  7. Propulsion system for a motor vehicle using a bidirectional energy converter

    SciTech Connect

    Tamor, M.A.; Gale, A.R.

    1999-12-07

    A motor vehicle propulsion system includes an electrical energy source and a traction motor coupled to receive electrical energy from the electrical energy source. The system also has a first bus provided electrical energy by the electrical energy source and a second bus of relatively lower voltage than the first bus. In addition, the system includes an electrically-driven source of reaction gas for the electrical energy source, the source of reaction gas coupled to receive electrical energy from the first bus. Also, the system has an electrical storage device coupled to the second bus for storing electrical energy at the lower voltage. The system also includes a bidirectional energy converter coupled to convert electrical energy from the first bus to the second bus and from the second bus to the first bus.

  8. Propulsion system for a motor vehicle using a bidirectional energy converter

    DOEpatents

    Tamor, Michael Alan; Gale, Allan Roy

    1999-01-01

    A motor vehicle propulsion system includes an electrical energy source and a traction motor coupled to receive electrical energy from the electrical energy source. The system also has a first bus provided electrical energy by the electrical energy source and a second bus of relatively lower voltage than the first bus. In addition, the system includes an electrically-driven source of reaction gas for the electrical energy source, the source of reaction gas coupled to receive electrical energy from the first bus. Also, the system has an electrical storage device coupled to the second bus for storing electrical energy at the lower voltage. The system also includes a bidirectional energy converter coupled to convert electrical energy from the first bus to the second bus and from the second bus to the first bus.

  9. On the concept of sloped motion for free-floating wave energy converters

    PubMed Central

    Payne, Grégory S.; Pascal, Rémy; Vaillant, Guillaume

    2015-01-01

    A free-floating wave energy converter (WEC) concept whose power take-off (PTO) system reacts against water inertia is investigated herein. The main focus is the impact of inclining the PTO direction on the system performance. The study is based on a numerical model whose formulation is first derived in detail. Hydrodynamics coefficients are obtained using the linear boundary element method package WAMIT. Verification of the model is provided prior to its use for a PTO parametric study and a multi-objective optimization based on a multi-linear regression method. It is found that inclining the direction of the PTO at around 50° to the vertical is highly beneficial for the WEC performance in that it provides a high capture width ratio over a broad region of the wave period range. PMID:26543397

  10. The Remote Maxwell Demon as Energy Down-Converter

    NASA Astrophysics Data System (ADS)

    Hossenfelder, S.

    2016-04-01

    It is demonstrated that Maxwell's demon can be used to allow a machine to extract energy from a heat bath by use of information that is processed by the demon at a remote location. The model proposed here effectively replaces transmission of energy by transmission of information. For that we use a feedback protocol that enables a net gain by stimulating emission in selected fluctuations around thermal equilibrium. We estimate the down conversion rate and the efficiency of energy extraction from the heat bath.

  11. Neural rotational speed control for wave energy converters

    NASA Astrophysics Data System (ADS)

    Amundarain, M.; Alberdi, M.; Garrido, A. J.; Garrido, I.

    2011-02-01

    Among the benefits arising from an increasing use of renewable energy are: enhanced security of energy supply, stimulation of economic growth, job creation and protection of the environment. In this context, this study analyses the performance of an oscillating water column device for wave energy conversion in function of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose, a model of neural rotational speed control system is presented, simulated and implemented. This scheme is employed to appropriately adapt the speed of the doubly-fed induction generator coupled to the turbine according to the pressure drop entry, so as to avoid the undesired stalling behaviour. It is demonstrated that the proposed neural rotational speed control design adequately matches the desired relationship between the slip of the doubly-fed induction generator and the pressure drop input, improving the power generated by the turbine generator module.

  12. Static Converter for High Energy Utilization, Modular, Small Nuclear Power Plants

    SciTech Connect

    El-Genk, Mohamed S.; Tournier, Jean-Michel P.

    2002-07-01

    This paper presents and analyzes the performance of high efficiency, high total energy utilization, static converters, which could be used in conjunction with small nuclear reactor plants in remote locations and in undersea applications, requiring little or no maintenance. The converters consist of a top cycle of Alkali Metal Thermal-to-Electric Conversion (AMTEC) units and PbTe thermoelectric (TE) bottom cycle. In addition to converting the reactor thermal power to electricity at 1150 K or less, at a thermodynamic efficiency in the low to mid thirties, the heat rejection from the TE bottom cycle could be used for space heating, industrial processing, or sea water desalination. The results indicated that for space heating applications, where the rejected thermal power from the TE bottom cycle is removed by natural convection of ambient air, a total utilization of the reactor thermal power of > 80% is possible. When operated at 1030 K, potassium AMTEC/TE converters are not only more efficient than the sodium AMTEC/TE converters but produce more electrical power. The present analysis showed that a single converter could be sized to produce up to 100 kWe and 70 kWe, for the Na-AMTEC/TE units when operating at 1150 K and the K-AMTEC/TE units when operating at 1030 K, respectively. Such modularity is an added advantage to the high-energy utilization of the present AMTEC/TE converters. (authors)

  13. Tunable wavelength terahertz polarization converter based on quartz waveplates.

    PubMed

    Kaveev, A K; Kropotov, G I; Tsypishka, D I; Tzibizov, I A; Vinerov, I A; Kaveeva, E G

    2014-08-20

    We present the results of calculation and experimental testing of the tunable wavelength terahertz polarization converter represented by a set of plane-parallel birefringent plates with an in-plane birefringence axis. An experimental device has been produced and tested. The calculations show that the effect of interference between the interfaces, including air gaps, may be neglected. The considered device may be used as a simple narrow achromatic waveplate, or a Solc band pass filter for the specified wavelength. PMID:25321112

  14. Muon detection studied by pulse-height energy analysis: Novel converter arrangements.

    PubMed

    Holmlid, Leif; Olafsson, Sveinn

    2015-08-01

    Muons are conventionally measured by a plastic scintillator-photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed. PMID:26329180

  15. Muon detection studied by pulse-height energy analysis: Novel converter arrangements

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif; Olafsson, Sveinn

    2015-08-01

    Muons are conventionally measured by a plastic scintillator-photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.

  16. Muon detection studied by pulse-height energy analysis: Novel converter arrangements

    SciTech Connect

    Holmlid, Leif; Olafsson, Sveinn

    2015-08-15

    Muons are conventionally measured by a plastic scintillator–photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.

  17. CONVERTING ENERGY FROM RECLAIMED HEAT: THERMAL ELECTRIC GENERATOR

    EPA Science Inventory

    The use of solar energy acquiring devices has been slow to gain acceptance due to their overall low power generation versus high cost of a solar system. The goal of this project is to construct a model which increases the overall power generation of a solar building system by...

  18. The Wave Carpet: An Omnidirectional and Broadband Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Alam, M.-Reza

    2015-11-01

    Inspired by the strong attenuation of ocean surface waves by muddy seafloors, we have designed, theoretically investigated the performance, and experimentally tested the ``Wave Carpet:'' a mud-resembling synthetic seabed-mounted mat composed of vertically-acting linear springs and generators that can be used as an efficient wave energy absorption device. The Wave Carpet is completely under the water surface hence imposes minimal danger to boats and the sea life (i.e. no mammal entanglement). It is survivable against the high momentum of storm surges and in fact can perform even better under very energetic (e.g. stormy) sea conditions when most existing wave energy devices are needed to shelter themselves by going into an idle mode. In this talk I will present an overview of analytical results for the linear problem, direct simulation of highly nonlinear wave fields, and results of the experimental wave tank investigation.

  19. Generalized Carrier-Based PWM Method for a 12-Switch Converter

    NASA Astrophysics Data System (ADS)

    Aganah, Kennedy Adinbo; Ojo, Olorunfemi

    2016-07-01

    This paper proposes a generalized carrier-based pulse-width modulation (CBPWM) method for a 12-switch converter feeding three independent loads. The converter topology is part of the (3N + 3)-switch converter family where N is the number of outputs (N = 3 for this special case). Its more famous sibling is the 9-switch converter which is gaining considerable interest from researchers because of its reduced-switch count architecture. The structure and limitations of the converter are elaborated; its modulation method applicable to both equal and different frequency (and/or amplitude) operations is formulated. The generalized neutral voltages for the converter is derived for the first time and used as the offset voltages required by this type of topology to decouple its three outputs. The proposed algorithm is validated by both theoretical simulations and experimental results.

  20. The research of multilevel transistor inverter for converting energy of solar panels

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2015-09-01

    This article considers multilevel transistor inverter for converting energy of solar panels into electroenergy. The output of multilevel transistor inverter produces the voltage of almost sinusoidal form. The primary objective of this inverter is to transform solar energy into electroenergy of industrial frequency. The analysis of received output curves of voltage for sinusoidality has been conducted.

  1. Frequency up-converted wide bandwidth piezoelectric energy harvester using mechanical impact

    NASA Astrophysics Data System (ADS)

    Halim, Miah A.; Khym, S.; Park, J. Y.

    2013-07-01

    This paper presents an impact based frequency up-converted wide bandwidth piezoelectric energy harvester in which two high frequency piezoelectric generating beams are struck at the same time by a low frequency driving beam having horizontally extended tip mass. Change of driving beam's effective stiffness during coupled vibration after impact allows the device to broaden the -3dB bandwidth to approximately 170% and to acquire more than 61% of the maximum power generation in the vicinity (from 7 to 10.5 Hz) of the -3 dB bandwidth region as well. The efficiency of electrical power transfer is increased to approximately 85%. Each generating beam produces 377 μW peak power at 14.5 Hz under 0.6 g acceleration with corresponding power density 58.8 μW cm-3.

  2. Low vapor pressure braze alloys for thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Bair, V. L.

    1976-01-01

    Preliminary results in the use of some low-vapor-pressure braze alloys are reported; these are binary alloys of refractory metals (Th, Zr, Hf, Ru, Nb, Ir, Mo, Ta, Os, Re, W) with vapor pressures below 0.1 nanotorr at 1500 K or 10 microtorr at 2000 K. The melting point minima or eutectics of the alloys range from 1510 K to above 3000 K. Melting points and surface wetting on a Ta base are given. Results are presented on brazing of Ir, LaB6, Nb, Re, W, and ZrO2 (with 22 wt % Zr) into a Ta base or a Nb-1% Zr base. The results are applicable in electrode screening programs for thermionic cesium diodes.

  3. Investigations of DC power supplies with optoelectronic transducers and RF energy converters

    NASA Astrophysics Data System (ADS)

    Guzowski, B.; Gozdur, R.; Bernacki, L.; Lakomski, M.

    2016-04-01

    Fiber Distribution Cabinets (FDC) monitoring systems are increasingly popular. However it is difficult to realize such system in passive FDC, due to lack of source of power supply. In this paper investigation of four different DC power supplies with optoelectronic transducers is described. Two converters: photovoltaic power converter and PIN photodiode can convert the light transmitted through the optical fiber to electric energy. Solar cell and antenna RF-PCB are also tested. Results presented in this paper clearly demonstrate that it is possible to build monitoring system in passive FDC. During the tests maximum obtained output power was 11 mW. However all converters provided enough power to excite 32-bit microcontroller with ARM-cores and digital thermometer.

  4. Underwater Noise from a Wave Energy Converter Is Unlikely to Affect Marine Mammals.

    PubMed

    Tougaard, Jakob

    2015-01-01

    Underwater noise was recorded from the Wavestar wave energy converter; a full-scale hydraulic point absorber, placed on a jack-up rig on the Danish North Sea coast. Noise was recorded 25 m from the converter with an autonomous recording unit (10 Hz to 20 kHz bandwidth). Median sound pressure levels (Leq) in third-octave bands during operation of the converter were 106-109 dB re. 1 μPa in the range 125-250 Hz, 1-2 dB above ambient noise levels (statistically significant). Outside the range 125-250 Hz the noise from the converter was undetectable above the ambient noise. During start and stop of the converter a more powerful tone at 150 Hz (sound pressure level (Leq) 121-125 dB re 1 μPa) was easily detectable. This tone likely originated from the hydraulic pump which was used to lower the absorbers into the water and lift them out of the water at shutdown. Noise levels from the operating wave converter were so low that they would barely be audible to marine mammals and the likelihood of negative impact from the noise appears minimal. A likely explanation for the low noise emissions is the construction of the converter where all moving parts, except for the absorbers themselves, are placed above water on a jack-up rig. The results may thus not be directly transferable to other wave converter designs but do demonstrate that it is possible to harness wave energy without noise pollution to the marine environment. PMID:26148299

  5. Underwater Noise from a Wave Energy Converter Is Unlikely to Affect Marine Mammals

    PubMed Central

    Tougaard, Jakob

    2015-01-01

    Underwater noise was recorded from the Wavestar wave energy converter; a full-scale hydraulic point absorber, placed on a jack-up rig on the Danish North Sea coast. Noise was recorded 25 m from the converter with an autonomous recording unit (10 Hz to 20 kHz bandwidth). Median sound pressure levels (Leq) in third-octave bands during operation of the converter were 106–109 dB re. 1 μPa in the range 125–250 Hz, 1–2 dB above ambient noise levels (statistically significant). Outside the range 125–250 Hz the noise from the converter was undetectable above the ambient noise. During start and stop of the converter a more powerful tone at 150 Hz (sound pressure level (Leq) 121–125 dB re 1 μPa) was easily detectable. This tone likely originated from the hydraulic pump which was used to lower the absorbers into the water and lift them out of the water at shutdown. Noise levels from the operating wave converter were so low that they would barely be audible to marine mammals and the likelihood of negative impact from the noise appears minimal. A likely explanation for the low noise emissions is the construction of the converter where all moving parts, except for the absorbers themselves, are placed above water on a jack-up rig. The results may thus not be directly transferable to other wave converter designs but do demonstrate that it is possible to harness wave energy without noise pollution to the marine environment. PMID:26148299

  6. Low vapor pressure braze alloys for thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Bair, V. L.

    1976-01-01

    The evaluation of cesium diode electrode materials called for braze fillers with very low vapor pressures and a wide range of melting points. Binary alloys of low vapor pressure refractory metals were chosen to fill this need. These alloys of Th, Zr, Hf, Ru, Nb, Ir, Mo, Ta, Os, Re, and W have reported melting point minima or eutectics from 1,510 K to above 3,000 K. Preliminary data are compiled on the use of several of these braze alloys. Melting points and surface wetting on a Ta base are given. Results of brazing Ir, LaB6, Nb, Re, W, and Zr-22 wt % ZrO2 materials into Ta and Nb-1% Zr bases are presented. Current braze usage is summarized.

  7. Criteria for the evaluation of laser solar energy converter systems

    NASA Technical Reports Server (NTRS)

    Harries, W. L.

    1985-01-01

    Assuming that a parabolic insolation-collection mirror-based solar pumped laser has a collector and heat emitter whose weights are proportional to their areas, and that the weight of the laser is negligible by comparison, the output power/unit weight can be expressed in terms of the efficiencies and working temperatures of the system. This ratio appears to be several times higher for an IBr laser than for one operating on C3F7I, because the solar utilization efficiency is greater for the former despite its lower working temperature.

  8. A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

    NASA Astrophysics Data System (ADS)

    Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

    2016-04-01

    Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

  9. Analog to digital converter for two-dimensional radiant energy array computers

    NASA Technical Reports Server (NTRS)

    Shaefer, D. H.; Strong, J. P., III (Inventor)

    1977-01-01

    The analog to digital converter stage derives a bit array of digital radiant energy signals representative of the amplitudes of an input radiant energy analog signal array and derives an output radiant energy analog signal array to serve as an input to succeeding stages. The converter stage includes a digital radiant energy array device which contains radiant energy array positions so that the analog array is less than a predetermined threshold level. A scaling device amplifies the radiant signal levels of the input array and the digital array so that the radiant energy signal level carried by the digital array corresponds to the threshold level. An adder device adds the signals of the scaled input and digital arrays at corresponding array positions to form the output analog array.

  10. Converting chemical energy into electricity through a functionally cooperating device with diving-surfacing cycles.

    PubMed

    Song, Mengmeng; Cheng, Mengjiao; Ju, Guannan; Zhang, Yajun; Shi, Feng

    2014-11-01

    A smart device that can dive or surface in aqueous medium has been developed by combining a pH-responsive surface with acid-responsive magnesium. The diving-surfacing cycles can be used to convert chemical energy into electricity. During the diving-surfacing motion, the smart device cuts magnetic flux lines and produces a current, demonstrating that motional energy can be realized by consuming chemical energy of magnesium, thus producing electricity. PMID:25146589

  11. Dielectric elastomer energy harvesting: maximal converted energy, viscoelastic dissipation and a wave power generator

    NASA Astrophysics Data System (ADS)

    Lv, Xiongfei; Liu, Liwu; Liu, Yanju; Leng, Jinsong

    2015-11-01

    Dielectric elastomer (DE) is a smart soft material. It is able to produce large deformation under mechanical force and electric field, so that it can achieve mutual conversion between mechanical energy and electrical energy. Based on this property, dielectric elastomer can be used in energy harvesting field. In this paper, firstly, we analyzed the constitutive relation under different hyperelastic models (Gent and neo-Hookean model) based on both theoretical and experimental study. Secondly, we depicted the allowable areas in force-displacement and voltage-charge plane according to different failure modes, and then calculated the maximal energy density in one energy harvesting period. Thirdly, we studied the viscoelastic energy dissipation which can lose the input mechanical energy in the energy harvesting process. Finally, we designed and fabricated a wave power generator, and tested its performance. This paper is of deep significance to the future applications of DE generators.

  12. An Improved Power Quality BIBRED Converter-Based VSI-Fed BLDC Motor Drive

    NASA Astrophysics Data System (ADS)

    Singh, Bhim; Bist, Vashist

    2014-01-01

    This paper presents an IHQRR (integrated high-quality rectifier regulator) BIBRED (boost integrated buck rectifier energy storage DC-DC) converter-based VSI (voltage source inverter)-fed BLDC (brushless DC) motor drive. The speed control of BLDC motor is achieved by controlling the DC link voltage of the VSI using a single voltage sensor. This allows VSI to operate in fundamental frequency switching mode for electronic commutation of BLDC motor which reduces the switching losses due to high-frequency switching used in conventional approach of PWM (pulse width modulation)-based VSI-fed BLDC motor drive. A BIBRED converter is operated in a dual-DCM (discontinuous conduction mode) thus using a voltage follower approach for PFC (power factor correction) and DC link voltage control. The performance of the proposed drive is evaluated for improved power quality over a wide range of speed control and supply voltage variation for demonstrating the behavior of proposed drive. The power quality indices thus obtained are within the recommended limits by international PQ (power quality) standards such as IEC 61000-3-2.

  13. Design considerations for a thermophotovoltaic energy converter using heat pipe radiators

    SciTech Connect

    Ashcroft, J.; DePoy, D.

    1997-06-01

    The purpose of this paper is to discuss concepts for using high temperature heat pipes to transport energy from a heat source to a thermophotovoltaic (TPV) converter. Within the converter, the condenser portion of each heat pipe acts as a photon radiator, providing a radiant flux to adjacent TPV cells, which in turn create electricity. Using heat pipes in this way could help to increase the power output and the power density of TPV systems. TPV systems with radiator temperatures in the range of 1,500 K are expected to produce as much as 3.6 W/cm{sup 3} of heat exchanger volume at an efficiency of 20% or greater. Four different arrangements of heat pipe-TPV energy converters are considered. Performance and sizing calculations for each of the concepts are presented. Finally, concerns with this concept and issues which remain to be considered are discussed.

  14. Essential anaplerotic role for the energy-converting hydrogenase Eha in hydrogenotrophic methanogenesis

    PubMed Central

    Lie, Thomas J.; Costa, Kyle C.; Lupa, Boguslaw; Korpole, Suresh; Whitman, William B.; Leigh, John A.

    2012-01-01

    Despite decades of study, electron flow and energy conservation in methanogenic Archaea are still not thoroughly understood. For methanogens without cytochromes, flavin-based electron bifurcation has been proposed as an essential energy-conserving mechanism that couples exergonic and endergonic reactions of methanogenesis. However, an alternative hypothesis posits that the energy-converting hydrogenase Eha provides a chemiosmosis-driven electron input to the endergonic reaction. In vivo evidence for both hypotheses is incomplete. By genetically eliminating all nonessential pathways of H2 metabolism in the model methanogen Methanococcus maripaludis and using formate as an additional electron donor, we isolate electron flow for methanogenesis from flux through Eha. We find that Eha does not function stoichiometrically for methanogenesis, implying that electron bifurcation must operate in vivo. We show that Eha is nevertheless essential, and a substoichiometric requirement for H2 suggests that its role is anaplerotic. Indeed, H2 via Eha stimulates methanogenesis from formate when intermediates are not otherwise replenished. These results fit the model for electron bifurcation, which renders the methanogenic pathway cyclic, and as such requires the replenishment of intermediates. Defining a role for Eha and verifying electron bifurcation provide a complete model of methanogenesis where all necessary electron inputs are accounted for. PMID:22872868

  15. Progress Towards the Development of a Traveling Wave Direct Energy Converter for Aneutronic Fusion Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Tarditi, A. G.; Chap, A.; Wolinsky, J.; Scott, J. H.

    2015-01-01

    A coordinated experimental and theory/simulation effort has been carried out to investigate the physics of the Traveling Wave Direct Energy Converter (TWDEC), a scheme that has been proposed in the past for the direct conversion into electricity of the kinetic energy of an ion beam generated from fusion reactions. This effort has been focused in particular on the TWDEC process in the high density beam regime, thus accounting for the ion beam expansion due to its space charge.

  16. High-efficiency, monolithic, multi-bandgap, tandem, photovoltaic energy converters

    DOEpatents

    Wanlass, Mark W

    2014-05-27

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  17. High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters

    DOEpatents

    Wanlass, Mark W.

    2011-11-29

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  18. Three-dimensional models of conventional and vertical junction laser-photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Walker, Gilbert H.

    1988-01-01

    Three-dimensional models of both conventional planar junction and vertical junction photovoltaic energy converters have been constructed. The models are a set of linear partial differential equations and take into account many photoconverter design parameters. The model is applied to Si photoconverters; however, the model may be used with other semiconductors. When used with a Nd laser, the conversion efficiency of the Si vertical junction photoconverter is 47 percent, whereas the efficiency for the conventional planar Si photoconverter is only 17 percent. A parametric study of the Si vertical junction photoconverter is then done in order to describe the optimum converter for use with the 1.06-micron Nd laser. The efficiency of this optimized vertical junction converter is 44 percent at 1 kW/sq cm.

  19. New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

    NASA Astrophysics Data System (ADS)

    Lopez, Juan Carlos; Ortega, Manuel; Jurado, Francisco

    2015-03-01

    This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.

  20. Terahertz-to-infrared converter based on metal nanoparticles: potentialities of applications

    NASA Astrophysics Data System (ADS)

    Moldosanov, Kamil A.; Lelevkin, Valery M.; Kozlov, Peter V.; Kaveev, Andrey K.

    2012-01-01

    In a new type of terahertz (THz)-to-infrared converter for the visualization of THz radiation sources, nanoparticles are embedded in a THz-transparent matrix material. The nanoparticles are made of a metal or an alloy having a partially filled peak of the electron density of states at the Fermi energy. The converter is designed to operate with the THz objective forming a source's image on the matrix, wherein the irradiated nanoparticles convert THz energy to thermal energy, whose spatial distribution is captured by an infrared camera. Nickel nanoparticles are very appropriate for high-frequency THz radiation and can find application in real-time passive imaging of biomedical objects at room temperature. Nanoparticles of compounds with heavy fermions are suitable for low-frequency THz radiation, which could be used to image concealed objects carried by a human being.

  1. Criteria for extending the operation periods of thermoelectric converters based on IV-VI compounds

    NASA Astrophysics Data System (ADS)

    Sadia, Yatir; Ohaion-Raz, Tsion; Ben-Yehuda, Ohad; Korngold, Meidad; Gelbstein, Yaniv

    2016-09-01

    The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations, had positioned the research of renewable energy conversion methods in general and of thermoelectric direct conversion of thermal into electrical energies in particular, in the forefront of the currently active applicative sciences. IV-VI thermoelectric compounds (e.g. GeTe, PbTe and SnTe) and their alloys comprise some of the most efficient thermoelectric compositions ever reported. Yet a proper utilization of such materials in practical thermoelectric devices, still requires an overcoming the so-called technological "valley of death", including among others, transport properties' degradation, due to sublimation of volatile Te rich species, while being subjected to elevated temperatures for long periods of time. In an attempt to establish practical operation criteria for extending the operation periods of such thermoelectric converters, it is currently shown based on thermal gravimetric and metallurgical considerations that such harmful sublimation can be practically bridged over by limiting the maximal operating temperatures to the 410-430 °C range for GeTe rich alloys and to 510-530 °C for PbTe and SnTe rich alloys, depending of the thermoelectric leg's diameter.

  2. Robust polarization-insensitive strip-slot waveguide mode converter based on symmetric multimode interference.

    PubMed

    Deng, Qingzhong; Yan, Qiaojing; Liu, Lu; Li, Xinbai; Michel, Jurgen; Zhou, Zhiping

    2016-04-01

    Strip-slot waveguide mode converters for TE0 have been widely investigated. Here we demonstrate a polarization-insensitive converter numerically and experimentally. The polarization-insensitive performance is achieved by matching the optical field distribution of the 2-fold image of the Multimode Interference (MMI) and the TE0 (TM0) mode of a slot waveguide. The working principle for this MMI-based mode converter is thoroughly analyzed with the quantitatively evaluated optical field overlap ratio that is theoretically derived from the orthonormal relation of eigenmodes. Based on the analysis, the MMI-based polarization-insensitive converters are then simulated and fabricated. The simulation and measurement results indicate that the proposed scheme is a robust design since it is not only polarization-insensitive but also wavelength-insensitive and fabrication-tolerant. Moreover, the mode converter is as small as 1.22 μm × 4 μm while the measured conversion efficiencies are 95.9% for TE0 and 96.6% for TM0. All these excellent properties make the proposed mode converter an ideal solution for coupling light between strip and slot waveguides when both TE and TM polarizations are considered. PMID:27137024

  3. Module-Integrated Power Converters Based on Universal Dock

    SciTech Connect

    Chapman, Patrick; Rodriguez, Fernando

    2015-03-13

    Solar power installations using alternating current photovoltaic (ACPV) modules have significant cost and performance advantages over systems using conventional solar modules and string inverters. ACPV modules have improved energy harvest due to module-level power point tracking and redundancy. More importantly, ACPV modules are easier and cheaper to install, lowering the total installed cost, indirect costs, and barriers to market entry. Furthermore, ACPV modules have communications and data logging capability, yielding module-level telemetry data that is useful in site diagnostics and other data applications. The products of these efforts were threefold. First, an advanced microinverter power topology was developed, modeled, simulated, and tested. Second, new microinverter enclosure concepts were developed and tested. Third, a new ACPV module prototype was constructed, combining the power topology and the enclosure concepts. SolarBridge filed for patents in each of these areas and is transitioning the project from a concept phase to full development.

  4. Development of a wind energy converter and investigation of its operational function. Part 4: Test setup and results of measurement

    NASA Astrophysics Data System (ADS)

    Armbrust, S.; Molly, J. P.

    1982-12-01

    Measurements made during test operations at the MODA.10 plant as well as at a 25 years old 6 kW wind energy converter are presented. The test arrangements, measurement results of both wind energy converters, and the experience gained are described.

  5. Oceanic Platform of the Canary Islands: an ocean testbed for ocean energy converters

    NASA Astrophysics Data System (ADS)

    González, Javier; Hernández-Brito, Joaquín.; Llinás, Octavio

    2010-05-01

    not particularly powerful with values around 40-50 cm/s. However a detailed assessment, based on field measurements, will be conducted in the near future with the aim to identify specific areas close to the coast with stronger currents which make suitable the deployment of marine current turbines. Although the base Platform is not still available, PLOCAN has already started the activity as an ocean testbed providing services to a wave energy converter patented by the Spanish company PIPO Systems. A scaled 1:5 prototype will be deployed during January 2010 and monitored for several months. Current facilities available include some ODAS buoys (temperature, salinity, pH, oxygen, turbidity, wind, etc.), wave rider buoy, current meter profilers (ADCP and electromagnetic), system for data management, remote operated vehicles (ROV), autonomous underwater vehicles (AUV), and an oceanographic vessel. Future facilities include high frequency radar for wave and current measurements and submarine electro-optical cables to connect the Platform with the energy converters and with the shore station.

  6. Improvement of burst-mode control of piezoelectric transformer based DC/DC converter

    NASA Astrophysics Data System (ADS)

    Vasic, Dejan; Liu, Yuan-Ping; Schwander, Denis; Costa, François; Wu, Wen-Jong

    2013-05-01

    Burst-mode operation is adopted sometimes in piezoelectric transformer based converters for two major purposes: (1) to achieve voltage regulation in DC/DC converters and (2) to achieve dimming control in backlight inverters. Burst-mode control enables the converter to operate at a constant switching frequency as well as to maintain good efficiency at light load conditions. However, in practice, the piezoelectric transformer cannot instantly stop vibrating in the burst-mode due to its high quality factor. The delay in the output voltage change resulting from this behavior influences the accuracy of the regulation. This paper proposes a control strategy to make the piezoelectric transformer stop more quickly so as to enhance the accuracy of burst-mode control. The proposed method only modifies the control signal of the burst-mode driving circuit. The proposed control strategy is verified by experiments in a step-down 9 W DC/DC converter.

  7. Surface plasmon polaritons one-way mode converter based on parity-time symmetry broken system

    NASA Astrophysics Data System (ADS)

    Yan, Xiang-An; Liu, Hanchen; Zhu, Changjun

    2016-03-01

    In this paper, we have proposed a novel periodic surface plasmon polariton (SPP) waveguide to realize a one-way mode converter which is based on a parity-time (PT) symmetry broken system, and it converts the fundamental TM mode to the first-order TM mode in only forward direction. Periodic gain potentials are put in place to construct the system mentioned in periodic SPP waveguide. Further, as the mode converter contains gain and loss material, light signals will be amplified when it propagates forward, and they will be attenuated toward when they propagate backward. The unidirectional mode converter has wide applications in nonlinearity induced isolation, mode insensitive element and on-chip mode locked laser.

  8. Preliminary Analysis of an Oscillating Surge Wave Energy Converter with Controlled Geometry: Preprint

    SciTech Connect

    Tom, Nathan; Lawson, Michael; Yu, Yi-Hsiang; Wright, Alan

    2015-09-09

    The aim of this paper is to present a novel wave energy converter device concept that is being developed at the National Renewable Energy Laboratory. The proposed concept combines an oscillating surge wave energy converter with active control surfaces. These active control surfaces allow for the device geometry to be altered, which leads to changes in the hydrodynamic properties. The device geometry will be controlled on a sea state time scale and combined with wave-to-wave power-take-off control to maximize power capture, increase capacity factor, and reduce design loads. The paper begins with a traditional linear frequency domain analysis of the device performance. Performance sensitivity to foil pitch angle, the number of activated foils, and foil cross section geometry is presented to illustrate the current design decisions; however, it is understood from previous studies that modeling of current oscillating wave energy converter designs requires the consideration of nonlinear hydrodynamics and viscous drag forces. In response, a nonlinear model is presented that highlights the shortcomings of the linear frequency domain analysis and increases the precision in predicted performance.

  9. Experimental Wave Tank Test for Reference Model 3 Floating-Point Absorber Wave Energy Converter Project

    SciTech Connect

    Yu, Y. H.; Lawson, M.; Li, Y.; Previsic, M.; Epler, J.; Lou, J.

    2015-01-01

    The U.S. Department of Energy established a reference model project to benchmark a set of marine and hydrokinetic technologies including current (tidal, open-ocean, and river) turbines and wave energy converters. The objectives of the project were to first evaluate the status of these technologies and their readiness for commercial applications. Second, to evaluate the potential cost of energy and identify cost-reduction pathways and areas where additional research could be best applied to accelerate technology development to market readiness.

  10. Converting hazardous organics into clean energy using a solar responsive dual photoelectrode photocatalytic fuel cell.

    PubMed

    Li, Jianyong; Li, Jinhua; Chen, Quanpeng; Bai, Jing; Zhou, Baoxue

    2013-11-15

    Direct discharging great quantities of organics into water-body not only causes serious environmental pollution but also wastes energy sources. In this paper, a solar responsive dual photoelectrode photocatalytic fuel cell (PFC(2)) based on TiO2/Ti photoanode and Cu2O/Cu photocathode was designed for hazardous organics treatment with simultaneous electricity generation. Under solar irradiation, the interior bias voltage produced for the Fermi level difference between photoelectrodes drives photoelectrons of TiO2/Ti photoanode to combine with photoholes of Cu2O/Cu photocathode through external circuit thus generating electricity. In the meantime, organics are decomposed by photoholes remained at TiO2/Ti photoanode. By using various hazardous organics including azo dyes as model pollutants, the PFC showed high converting performance of organics into electricity. For example, in 0.05 M phenol solution, a short-circuit current density 0.23 mA cm(-2), open-circuit voltage 0.49 V, maximum power output 0.3610(-4)W cm(-2) was achieved. On the other hand, removal rate of chroma reached 67%, 87% and 63% in 8h for methyl orange, methylene blue, Congo red, respectively. PMID:24051045

  11. Dynamics of a mechanical frequency up-converted device for wave energy harvesting

    NASA Astrophysics Data System (ADS)

    Lin, Zheng; Zhang, Yongliang

    2016-04-01

    This paper proposes a novel mechanical impact-driven frequency up-converted device for wave energy harvesting, which could bridge a gap between waves of frequency 0.03-1 Hz and electrical generators of operation frequency hundreds hertz. The device mainly consists of a cylindrical buoy, beams and teeth. A mathematical model for the dynamics of such a device is presented, which incorporates the fluid-structure interaction between the wave and the buoy, and the structural interactions between the beams and the teeth. The momentum balance method and the coefficient of restitution are employed, which give rise to piecewise nonlinear equations governing the motions of the buoy and the beams. Experimental tests carried out in a wave flume validate the model and prove the effectiveness of frequency up-converted method in wave energy harvesting. The characteristics of frequency up-converted transformation from buoy motion to beams oscillation for wave energy harvesting are probed, and the effects of beam Young's modulus, beam number, wave period and wave height on strain power of the beams are explored.

  12. From Mainframe to Micro: Converting a Computer-Based Management Game.

    ERIC Educational Resources Information Center

    Burkhard, Donald L.; Watson, Hugh J.

    1989-01-01

    Discussion of the impact of microcomputers on gaming focuses on converting a mainframe-based game to a microcomputer. Software, hardware, and documentation are considered, and a case study is presented that describes the conversion of a mainframe-based management game--the Credit Union Management Game--to a microcomputer. (11 references) (LRW)

  13. A 10kW series resonant converter design, transistor characterization, and base-drive optimization

    NASA Technical Reports Server (NTRS)

    Robson, R.; Hancock, D.

    1981-01-01

    Transistors are characterized for use as switches in resonant circuit applications. A base drive circuit to provide the optimal base drive to these transistors under resonant circuit conditions is developed and then used in the design, fabrication and testing of a breadboard, spaceborne type 10 kW series resonant converter.

  14. Temporal response analysis of a fluorescence-based thermal to visible converter

    NASA Astrophysics Data System (ADS)

    Alfaro, Mariana; Paez, Gonzalo; Strojnik, Marija

    2011-09-01

    Today's room temperature microbolometers focal plane arrays are the most widespread technology for the registration of thermal images. Other attempts to develop detection systems are based on the idea of converting the thermal information into visible. Thermal to visible converters try to achieve the possibility of "detecting" thermal radiation with common visible detectors. The development of these converters may provide IR and thermal detection methods for specific thermal imaging applications without excessive investment. Previously, we have proposed a conversion method based on temperature dependence of the fluorescence emission of a europium-doped complex. Here, we present the analysis of the temporal response of the sensing element and we also specify the desirable thermal and physical characteristics of such element in order to allow thermal to visible conversion in real time. With the analysis of the frequency response of the EuTTA fluorescence, we find that the emission presents a response that allows dynamic conversion. Furthermore, we analyze the thermal-transient response of the sensing element of the converter. Based on heat transfer simulation of a pixel of the sensing element, we establish the characteristics that the thermal design should fulfill in order to have efficient heat transfer in a dynamic converter.

  15. Digital computer simulation of inductor-energy-storage dc-to-dc converters with closed-loop regulators

    NASA Technical Reports Server (NTRS)

    Ohri, A. K.; Owen, H. A.; Wilson, T. G.; Rodriguez, G. E.

    1974-01-01

    The simulation of converter-controller combinations by means of a flexible digital computer program which produces output to a graphic display is discussed. The procedure is an alternative to mathematical analysis of converter systems. The types of computer programming involved in the simulation are described. Schematic diagrams, state equations, and output equations are displayed for four basic forms of inductor-energy-storage dc to dc converters. Mathematical models are developed to show the relationship of the parameters.

  16. An ocean kinetic energy converter for low-power applications using piezoelectric disk elements

    NASA Astrophysics Data System (ADS)

    Viñolo, C.; Toma, D.; Mànuel, A.; del Rio, J.

    2013-09-01

    The main problem facing long-term electronic system deployments in the sea, is to find a feasible way to supply them with the power they require. Harvesting mechanical energy from the ocean wave oscillations and converting it into electrical energy, provides an alternative method for creating self-contained power sources. However, the very low and varying frequency of ocean waves, which generally varies from 0.1 Hz to 2 Hz, presents a hurdle which has to be overcome if this mechanical energy is to be harvested. In this paper, a new sea wave kinetic energy converter is described using low-cost disk piezoelectric elements, which has no dependence on their excitement frequency, to feed low-consumption maritime-deployed electronic devices. The operating principles of the piezoelectric device technique are presented, including analytical formulations describing the transfer of energy. Finally, a prototypical design, which generates electrical energy from the motion of a buoy, is introduced. The paper concludes with the the behavior study of the piezoelectric prototype device as a power generator.

  17. High efficiency 160 Gb/s all-optical wavelength converter based on terahertz optical asymmetric demultiplexer with quantum dot semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Han, Huining; Zhang, Fangdi; Yang, Wei; Cai, Libo; Zhang, Min; Ye, Peida

    2007-11-01

    Proposed in this paper is a high efficient 160Gb/s all-optical wavelength converter based on terahertz optical asymmetric demultiplexer with quantum dot Semiconductor optical amplifier (QDSOA -TOAD). The performance of the wavelength converter under various operating conditions, such as different injected current densities, input pulse widths and input control pulse energies, is analyzed in terms of contrast ratio (CR) through numerical simulations. With the properly chosen parameters, a wavelength-converted signal with CR over 19.48 can be obtained.

  18. Novel bidirectional DC-DC converters based on the three-state switching cell

    NASA Astrophysics Data System (ADS)

    da Silva Júnior, José Carlos; Robles Balestero, Juan Paulo; Lessa Tofoli, Fernando

    2016-05-01

    It is well known that there is an increasing demand for bidirectional DC-DC converters for applications that range from renewable energy sources to electric vehicles. Within this context, this work proposes novel DC-DC converter topologies that use the three-state switching cell (3SSC), whose well-known advantages over conventional existing structures are ability to operate at high current levels, while current sharing is maintained by a high frequency transformer; reduction of cost and dimensions of magnetics; improved distribution of losses, with consequent increase of global efficiency and reduction of cost associated to the need of semiconductors with lower current ratings. Three distinct topologies can be derived from the 3SSC: one DC-DC converter with reversible current characteristic able to operate in the first and second quadrants; one DC-DC converter with reversible voltage characteristic able to operate in the first and third quadrants and one DC-DC converter with reversible current and voltage characteristics able to operate in four quadrants. Only the topology with bidirectional current characteristic is analysed in detail in terms of the operating stages in both nonoverlapping and overlapping modes, while the design procedure of the power stage elements is obtained. In order to validate the theoretical assumptions, an experimental prototype is also implemented, so that relevant issues can be properly discussed.

  19. A Rigorous Analysis of Series-Connected, Multi-Bandgap, Tandem Thermophotovoltaic (TPV) Energy Converters

    NASA Astrophysics Data System (ADS)

    Wanlass, M. W.; Albin, D. S.

    2004-11-01

    Multi-bandgap, photonic energy conversion is under investigation for nearly every class of photovoltaic materials, with monolithic, series-connected device structures being the preferred mode of implementation. For TPV energy conversion systems, such an approach represents the next wave in TPV converter advancement. In this paper, we focus on a rigorous analysis of series-connected, multi-bandgap, tandem (SCMBT) converter structures according to Kirchhoff's circuit laws. A general formulation is presented, followed by an application of the general formulation to a typical, semi-realistic model for well-behaved, p-n junction, photovoltaic devices. Using results generated from a computer code written in Visual Basic, we then present example calculations for SCMBT TPV converters with two subcells, for a TPV system utilizing a blackbody radiator operating at 954°C (1750°F). A comparison of the results obtained using the rigorous analysis, with those obtained by using the commonly adopted subcell-photocurrent-matching design rule, is discussed in detail. An output power density increase of ˜ 5% is realized in the solution determined by the rigorous analysis, as compared to that obtained with the subcell-photocurrent-matching rule. Additional interesting, non-intuitive results are also highlighted.

  20. The characterization and application of a low resource FPGA-based time to digital converter

    NASA Astrophysics Data System (ADS)

    Balla, Alessandro; Mario Beretta, Matteo; Ciambrone, Paolo; Gatta, Maurizio; Gonnella, Francesco; Iafolla, Lorenzo; Mascolo, Matteo; Messi, Roberto; Moricciani, Dario; Riondino, Domenico

    2014-03-01

    Time to Digital Converters (TDCs) are very common devices in particles physics experiments. A lot of "off-the-shelf" TDCs can be employed but the necessity of a custom DAta acQuisition (DAQ) system makes the TDCs implemented on the Field-Programmable Gate Arrays (FPGAs) desirable. Most of the architectures developed so far are based on the tapped delay lines with precision down to 10 ps, obtained with high FPGA resources usage and non-linearity issues to be managed. Often such precision is not necessary; in this case TDC architectures with low resources occupancy are preferable allowing the implementation of data processing systems and of other utilities on the same device. In order to reconstruct γγ physics events tagged with High Energy Tagger (HET) in the KLOE-2 (K LOng Experiment 2), we need to measure the Time Of Flight (TOF) of the electrons and positrons from the KLOE-2 Interaction Point (IP) to our tagging stations (11 m apart). The required resolution must be better than the bunch spacing (2.7 ns). We have developed and implemented on a Xilinx Virtex-5 FPGA a 32 channel TDC with a precision of 255 ps and low non-linearity effects along with an embedded data acquisition system and the interface to the online FARM of KLOE-2. The TDC is based on a low resources occupancy technique: the 4×Oversampling technique which, in this work, is pushed to its best resolution and its performances were exhaustively measured.

  1. Semiconductor up-converter based on cascade carrier transport for infrared detection/imaging

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Hao, Zhi-Biao; Luo, Yi; Kang, Jian-Bin; Wang, Lai; Xiong, Bing; Sun, Chang-Zheng; Wang, Jian; Han, Yan-Jun; Li, Hong-Tao; Wang, Lu; Wang, Wen-Xin; Chen, Hong

    2015-09-01

    The next generation infrared (IR) detection and imaging technology calls for very large-scale IR sensitive chips with non-compromised performance. IR up-converters based on mature III-V semiconductors are thought to be quite promising candidates. However, the up-converters and the corresponding up-conversion systems so far substantially fall behind traditional IR detectors in terms of device performance due to the more serious trade-off between responsivity and dark current. In this article, a cascade infrared up-converter (CIUP) is proposed. By employing cascade carrier transport, IR responsivity can be enhanced while dark current remains in fairly low level. For the fabricated 4-μm InGaAs/AlGaAs CIUP under 3.3 V at 78 K, the up-conversion efficiency of the system is 2.1 mW/W under 2.1 μW mid-infrared input. Both the up-converter and the up-conversion system are under background-limited infrared performance regime below 120 K. Taking shot noise as the main source of system noise, the CIUP system displays a higher detectivity than previous semiconductor up-converters at similar wavelengths, and thus possesses greater potential for future large-scale IR detection and imaging applications.

  2. Consequences of Converting Graded to Action Potentials upon Neural Information Coding and Energy Efficiency

    PubMed Central

    Sengupta, Biswa; Laughlin, Simon Barry; Niven, Jeremy Edward

    2014-01-01

    Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na+ and K+ channels, with generator potential and graded potential models lacking voltage-gated Na+ channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na+ channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a ‘footprint’ in the generator potential that obscures incoming signals. These three processes reduce information rates by ∼50% in generator potentials, to ∼3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation. PMID:24465197

  3. Consequences of converting graded to action potentials upon neural information coding and energy efficiency.

    PubMed

    Sengupta, Biswa; Laughlin, Simon Barry; Niven, Jeremy Edward

    2014-01-01

    Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na(+) and K(+) channels, with generator potential and graded potential models lacking voltage-gated Na(+) channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na(+) channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a 'footprint' in the generator potential that obscures incoming signals. These three processes reduce information rates by ∼50% in generator potentials, to ∼3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation. PMID:24465197

  4. Ultra-compact broadband nanowire-to-slot waveguide mode converter based on SOI

    NASA Astrophysics Data System (ADS)

    Qi, Ying; An, Junming; Wang, Yue; Zhang, Xiaoguang

    2014-11-01

    A novel ultra-compact high-efficiency broadband mode converter between silicon (Si) nanowire and silicon slot waveguide based on Silicon-on-Insulator (SOI) is proposed in this paper. By introducing a gradual-width structure between Si nanowire and slot waveguide, the favorable transition between nanowire mode (Gaussian-like mode) and slot mode (non-Gaussian-like mode) can be obtained and then the coupling efficiency is improved. The structure is simulated and optimized by using the three-dimension Finite-Difference Time-Domain Method (3D-FDTD). The coupling efficiency of over 90% within bandwidth of over 600nm can be achieved by only 200nm-length converter which is the smallest size to our knowledge. This presented mode converter can meet the demand of ultra-compact, wavelength-insensitive of monolithic integration.

  5. Zigzag Connected Autotransformer-Based 24-pulse AC-DC Converter

    NASA Astrophysics Data System (ADS)

    Xiao-qiang, Chen; Hao, Qiu

    2015-02-01

    In this paper, a zigzag connected autotransformer-based 24-pulse AC-DC converter is designed, modeled and simulated to feed direct torque controlled induction motor drives. Winding arrangements and parameters of the autotransformer and interphase reactor are given. Moreover, the design procedure of the autotransformer is modified to make it suitable for retrofit applications. Simulation results indicate that the system is capable of eliminating up to 21st harmonics in the ac mains current. The effect of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 24-pulse converters. A set of power quality indices at ac mains and dc side are presented to compare the performance of 6-, 12- and 24-pulse converters.

  6. TCD: A Text-Based UML Class Diagram Notation and Its Model Converters

    NASA Astrophysics Data System (ADS)

    Washizaki, Hironori; Akimoto, Masayoshi; Hasebe, Atsushi; Kubo, Atsuto; Fukazawa, Yoshiaki

    Among several diagrams defined in UML, the class diagram is particularly useful through entire software development process, from early domain analysis stages to later maintenance stages. However conventional UML environments are often inappropriate for collaborative modeling in physically remote locations, such as exchanging models on a public mailing list via email. To overcome this issue, we propose a new diagram notation, called "TCD" (Text-based uml Class Diagram), for describing UML class diagrams using ASCII text. Since text files can be easily created, modified and exchanged in anywhere by any computing platforms, TCD facilitates the collaborative modeling with a number of unspecified people. Moreover, we implemented model converters for converting in both directions between UML class diagrams described in the XMI form and those in the TCD form. By using the converters, the reusability of models can be significantly improved because many of UML modeling tools support the XMI for importing and exporting modeling data.

  7. ZVS Full-Bridge Based DC-DC Converter with Linear Voltage Gain According to Duty Cycle

    NASA Astrophysics Data System (ADS)

    Do, Hyun-Lark

    2013-09-01

    This paper presents a zero-voltage-switching (ZVS) full-bridge based DC-DC converter with linear voltage gain according to duty cycle. The proposed converter is based on an asymmetrical pulse-width-modulation (APWM) full-bridge converter which has various advantages over other converters. However, it has some drawbacks such as limited maximum duty cycle to 0.5 and narrow input range. The proposed converter overcomes these problems. The duty cycle is not limited and input voltage range is wide. Also, the ZVS operation of all power switches is achieved. Therefore, switching losses are significantly reduced and high-efficiency is obtained. Steady-state analysis and experimental results for the proposed converter are presented to validate the feasibility and the performance of the proposed converter.

  8. Research on Integration of an Automotive Exhaust-Based Thermoelectric Generator and a Three-Way Catalytic Converter

    NASA Astrophysics Data System (ADS)

    Deng, Y. D.; Chen, Y. L.; Chen, S.; Xianyu, W. D.; Su, C. Q.

    2015-06-01

    A key research topic related to thermoelectric generators (TEGs) for automotive applications is to improve their compatibility with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. A new TEG integrated with a three-way catalytic converter (CTEG) by reshaping the converter as the heat exchanger is proposed. A heat-flux coupling simulation model of the integrated TEG is established at the light-off stage of the original three-way catalytic converter (TWC). Temperature distribution maps of the integrated heat exchanger, thermoelectric modules, and cooling-water tank are obtained to present the process of energy flow among the parts of the CTEG. Based on the simulation results, the output power of the CTEG is calculated by a mathematical model. A minimum output power of 31.93 W can be obtained by conversion when the TWC starts working at steady conditions. Theoretically, this case study demonstrates the great potential for use of CTEGs in vehicles.

  9. Conversion of NO to NO(2) in air by a micro electric NO(x) converter based on a corona discharge process.

    PubMed

    Yoon, Seung-Il; Heo, Sungmoo; Song, Soonho; Kim, Yong-Jun

    2010-06-01

    A micro-electric-NO(x)-converter based on volume treatment is proposed for the evaluation of NO(x) concentrations in air. It can electrically convert NO(x) mixture from variable mixing rates into a fixed-mixing rate of 25% NO(2) and 75% NO using the corona discharge process with stable conversion efficiency and high throughput (space velocity = 6.3 x 10(4) h(-1)). The micro-electric-NO(x)-converter is based on a volume process. Applying high voltage to the electrodes of the micro-electric-NO(x)-converter generates a corona discharge. This discharge creates high-energy electrons, which collide with gas molecules. After these collisions, NO and O(2) are broken into single atoms, and they are re-combined as a balanced form, NO(2) in this case. The fabricated micro-electric-NO(x)-converter converted NO into NO(2) at conversion efficiency of 25.63%, when 5.5 kV (the applied corona power = 0.196 W) was applied to the micro-electric-NO(x)-converter. PMID:20498882

  10. An experimental study of SO3 dissociation as a mechanism for converting and transporting solar energy

    NASA Technical Reports Server (NTRS)

    Mccrary, J. H.; Mccrary, G. E.; Chubb, T. A.; Won, Y. S.

    1981-01-01

    The high temperature catalytic dissocation of SO3 is an important chemical process being considered in the development and application of solar-thermal energy conversion, transport, and storage systems. A facility for evaluating chemical converter-heat exchangers at temperatures to 1000 C with high flow rates of gaseous SO3 feedstock has been assembled and operated on the NMSU campus. Several quartz and metal reactors containing different catalyst configurations have been tested. Descriptions of the test facility and of the reactors are given along with a presentation and discussion of experimental results.

  11. A review of the thermoelectronic laser energy converter (TELEC) program at Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Manista, E. J.; Thompson, R. W.

    1978-01-01

    The investigation of the Thermoelectronic Laser Energy Converter (TELEC) concept began with a feasibility study of a 1 megawatt sized TELEC system. The TELEC was to use either cesium vapor or hydrogen as the plasma medium. The cesium vapor TELEC appears to be the more practical device studied with an overall calculated conversion efficiency of greater than 48%. Following this study, a small TELEC cell was fabricated which demonstrated the conversion of a small amount of laser power to electrical power. The cell developed a short circuit current of 0.7 amperes and an open circuit voltage, as extrapolated from volt-ampere curves, of about 1.5 volts.

  12. Effects of rotor solidity on the performance of impulse turbine for OWC wave energy converter

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Zhao, Huan-yu; Cui, Ying

    2015-10-01

    Impulse turbine, working as a typical self-rectifying turbine, is recently utilized for the oscillating water column (OWC) wave energy converters, which can rotate in the same direction under the bi-directional air flows. A numerical model established in Fluent is validated by the corresponding experimental results. The flow fields, pressure distribution and dimensionless evaluating coefficients can be calculated and analyzed. Effects of the rotor solidity varying with the change of blade number are investigated and the suitable solidity value is recommended for different flow coefficients.

  13. Absorption of solar radiation by alkali vapors. [for efficient high temperature energy converters

    NASA Technical Reports Server (NTRS)

    Mattick, A. T.

    1978-01-01

    A theoretical study of the direct absorption of solar radiation by the working fluid of high temperature, high efficiency energy converters has been carried out. Alkali vapors and potassium vapor in particular were found to be very effective solar absorbers and suitable thermodynamically for practical high temperature cycles. Energy loss via reradiation from a solar boiler was shown to reduce the overall efficiency of radiation-heated energy converters, although a simple model of radiation transfer in a potassium vapor solar boiler revealed that self-trapping of the reradiation may reduce this loss considerably. A study was also made of the requirements for a radiation boiler window. It was found that for sapphire, one of the best solar transmitting materials, the severe environment in conjunction with high radiation densities will require some form of window protection. An aerodynamic shield is particularly advantageous in this capacity, separating the window from the absorbing vapor to prevent condensation and window corrosion and to reduce the radiation density at the window.

  14. Optical cross-polarization converter with an octave bandwidth based on anisotropic plasmonic meta-surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Song, Zhengyong; Huo Liu, Qing

    2015-07-01

    We show that the linear polarization state of electromagnetic waves can be efficiently rotated to its orthogonal direction by an alternative design of anisotropic plasmonic meta-surfaces. Numerical results demonstrate that the reflection coefficient converting to cross-polarization after reflection is larger than 71% within an octave frequency band from ∼232 \\text{THz} to ∼490 \\text{THz} . The designed system is much thinner than conventional geometric-optics devices, and takes favorable advantage of little energy loss.

  15. A column-based two-stage analog-to-digital converter for uncooled microbolometer arrays

    NASA Astrophysics Data System (ADS)

    Toprak, Alperen; Tepegoz, Murat; Akin, Tayfun

    2009-05-01

    This paper presents a column-based, two-stage, 12-bit analog-to-digital converter structure designed for uncooled microbolometer arrays. On-chip analog-to-digital converters prevent the degradation of sensitive analog output by external noise sources as well as providing a more integrated functionality. Despite these advantages, the area and power constraints limit the usage of high performance converters. This paper presents a new structure that provides a balance between area, power, and performance. The structure is composed of two stages: a tracking ADC stage running at each column during integration and a successive approximation ADC stage which is shared by a number of columns depending on the array size and operation frequency. The tracking ADC operates during the integration time, while the second ADC starts after the integration is completed. The converter includes self-calibration to lower the effect of process variations and digital correction mechanisms to eliminate the need for low-offset comparators. The simulations and theoretical calculations based on the simulation results show that the total power dissipation of the proposed structure will be approximately 73.7 mW and 88.4 mW on a 320x240 array operating at 60 Hz and 384x288 array operating at 50 Hz, respectively.

  16. Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

    PubMed Central

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  17. Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

    PubMed

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  18. Individual Battery-Power Control for a Battery Energy Storage System Using a Modular Multilevel Cascade Converter

    NASA Astrophysics Data System (ADS)

    Yamagishi, Tsukasa; Maharjan, Laxman; Akagi, Hirofumi

    This paper focuses on a battery energy storage system that can be installed in a 6.6-kV power distribution system. This system comprises a combination of a modular multilevel cascade converter based on single-star bridge-cells (MMCC-SSBC) and multiple battery modules. Each battery module is connected to the dc side of each bridge-cell, where the battery modules are galvanically isolated from each other. Three-phase multilevel line-to-line voltages with extremely low voltage steps on the ac side of the converter help in solving problems related to line harmonic currents and electromagnetic interference (EMI) issues. This paper proposes a control method that allows each bridge-cell to independently adjust the battery power flowing into or out of each battery module. A three-phase energy storage system using nine nickel-metal-hydride (NiMH) battery modules, each rated at 72V and 5.5Ah, is designed, constructed, and tested to verify the viability and effectiveness of the proposed control method.

  19. Wave Energy Converter (WEC) Array Effects on Wave Current and Sediment Circulation: Monterey Bay CA.

    SciTech Connect

    Roberts, Jesse D.; Jones, Craig; Magalen, Jason

    2014-09-01

    The goal s of this study were to develop tools to quantitatively characterize environments where wave energy converter ( WEC ) devices may be installed and to assess e ffects on hydrodynamics and lo cal sediment transport. A large hypothetical WEC array was investigated using wave, hydrodynamic, and sediment transport models and site - specific average and storm conditions as input. The results indicated that there were significant changes in sediment s izes adjacent to and in the lee of the WEC array due to reduced wave energy. The circulation in the lee of the array was also altered; more intense onshore currents were generated in the lee of the WECs . In general, the storm case and the average case show ed the same qualitative patterns suggesting that these trends would be maintained throughout the year. The framework developed here can be used to design more efficient arrays while minimizing impacts on nearshore environmen ts.

  20. Numerical Modeling of Compliant-Moored System Dynamics with Applications to Marine Energy Converters

    NASA Astrophysics Data System (ADS)

    Nichol, Tyler

    The development of a numerical model simulating the dynamic response of compliant-moored submerged systems to non-uniform fluid flow is presented. The model is meant to serve as a computational tool with applications to compliant-moored marine energy converters by time-domain representation of the mooring dynamics. The scope of the initial code is restricted to full-submerged moored tidal turbines, though the model can be readily expanded to analyze wave energy converters as well. The system is modeled in a Lagrangian frame treating tidal turbines and structural elements as rigid bodies. Mooring lines are modeled as a series of discrete elastic segments, with parameters and force contributions lumped to point-mass nodes joining each segment. Full-range of motion is achieved using the alpha-beta-gamma Euler Angle method. The governing equations of motion of the system are derived computationally through implementation of Lagrange's Equation of Motion. The techniques employed to develop the symbolic expressions for the total kinetic, potential, and damping energies of the system and the forces acting on each element of the system are discussed. The system of differential equations obtained from evaluation of Lagrange's Equation with the developed symbolic expressions is solved numerically using a built-in MATLAB ordinary differential equation solver called ODE15i.m with the user defined initial condition of the system. Several validation tests are presented and their results discussed. Finally, an explanation of future plans for development of the model and application to existing tidal energy systems are presented.

  1. Optoelectronic optimization of mode selective converter based on liquid crystal on silicon

    NASA Astrophysics Data System (ADS)

    Wang, Yongjiao; Liang, Lei; Yu, Dawei; Fu, Songnian

    2016-03-01

    We carry out comprehensive optoelectronic optimization of mode selective converter used for the mode division multiplexing, based on liquid crystal on silicon (LCOS) in binary mode. The conversion error of digital-to-analog (DAC) is investigated quantitatively for the purpose of driving the LCOS in the application of mode selective conversion. Results indicate the DAC must have a resolution of 8-bit, in order to achieve high mode extinction ratio (MER) of 28 dB. On the other hand, both the fast axis position error of half-wave-plate (HWP) and rotation angle error of Faraday rotator (FR) have negative influence on the performance of mode selective conversion. However, the commercial products provide enough angle error tolerance for the LCOS-based mode selective converter, taking both of insertion loss (IL) and MER into account.

  2. Cow power: the energy and emissions benefits of converting manure to biogas

    NASA Astrophysics Data System (ADS)

    Cuéllar, Amanda D.; Webber, Michael E.

    2008-07-01

    This report consists of a top-level aggregate analysis of the total potential for converting livestock manure into a domestic renewable fuel source (biogas) that could be used to help states meet renewable portfolio standard requirements and reduce greenhouse gas (GHG) emissions. In the US, livestock agriculture produces over one billion tons of manure annually on a renewable basis. Most of this manure is disposed of in lagoons or stored outdoors to decompose. Such disposal methods emit methane and nitrous oxide, two important GHGs with 21 and 310 times the global warming potential of carbon dioxide, respectively. In total, GHG emissions from the agricultural sector in the US amounted to 536 million metric tons (MMT) of carbon dioxide equivalent, or 7% of the total US emissions in 2005. Of this agricultural contribution, 51 to 118 MMT of carbon dioxide equivalent resulted from livestock manure emissions alone, with trends showing this contribution increasing from 1990 to 2005. Thus, limiting GHG emissions from manure represents a valuable starting point for mitigating agricultural contributions to global climate change. Anaerobic digestion, a process that converts manure to methane-rich biogas, can lower GHG emissions from manure significantly. Using biogas as a substitute for other fossil fuels, such as coal for electricity generation, replaces two GHG sources—manure and coal combustion—with a less carbon-intensive source, namely biogas combustion. The biogas energy potential was calculated using values for the amount of biogas energy that can be produced per animal unit (defined as 1000 pounds of animal) per day and the number of animal units in the US. The 95 million animal units in the country could produce nearly 1 quad of renewable energy per year, amounting to approximately 1% of the US total energy consumption. Converting the biogas into electricity using standard microturbines could produce 88 ± 20 billion kWh, or 2.4 ± 0.6% of annual electricity

  3. Improved design of a polarization converter based on semiconductor optical waveguide bends.

    PubMed

    Obayya, S S; Rahman, B M; Grattan, K T; El-Mikati, H A

    2001-10-20

    By using an efficient vector finite-element-based beam-propagation method, we present an improved design of a polarization converter. This design relies on the use of a single-section deeply etched bent semiconductor waveguide with slanted sidewalls. By careful adjustment of the bend radius, the waveguide width, and the sidewall angle we obtained a nearly 100% polarization conversion ratio with no appreciable radiation loss and a bending angle of less than 180 degrees . PMID:18364819

  4. Novel anti-jamming technique for OCDMA network through FWM in SOA based wavelength converter

    NASA Astrophysics Data System (ADS)

    Jyoti, Vishav; Kaler, R. S.

    2013-06-01

    In this paper, we propose a novel anti-jamming technique for optical code division multiple access (OCDMA) network through four wave mixing (FWM) in semiconductor optical amplifier (SOA) based wavelength converter. OCDMA signal can be easily jammed with high power jamming signal. It is shown that wavelength conversion through four wave mixing in SOA has improved capability of jamming resistance. It is observed that jammer has no effect on OCDMA network even at high jamming powers by using the proposed technique.

  5. Design of an Integrated Thermoelectric Generator Power Converter for Ultra-Low Power and Low Voltage Body Energy Harvesters aimed at EEG/ECG Active Electrodes

    NASA Astrophysics Data System (ADS)

    Ataei, Milad; Robert, Christian; Boegli, Alexis; Farine, Pierre-André

    2014-11-01

    This paper describes a design procedure for an efficient body thermal energy harvesting integrated power converter. This procedure is based on loss examination for a selfpowered medical device. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. It is found that it is possible to optimize converter's working frequency with proper design of its pulse generator circuit. At selected frequency, it has been demonstrated that wide area voltage doubler can be eliminated at the expense of wider switches. With this method, more than 60% efficiency is achieved in simulation for just 20mV transducer output voltage and 30% of entire chip area is saved.

  6. A novel design of DC-AC electrical machine rotary converter for hybrid solar and wind energy applications

    NASA Astrophysics Data System (ADS)

    Mohammed, K. G.; Ramli, A. Q.; Amirulddin, U. A. U.

    2013-06-01

    This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.

  7. An Improved Power Quality Based Sheppard-Taylor Converter Fed BLDC Motor Drive

    NASA Astrophysics Data System (ADS)

    Singh, Bhim; Bist, Vashist

    2015-12-01

    This paper deals with the design and analysis of a power factor correction based Sheppard-Taylor converter fed brushless dc motor (BLDCM) drive. The speed of the BLDCM is controlled by adjusting the dc link voltage of the voltage source inverter (VSI) feeding BLDCM. Moreover, a low frequency switching of the VSI is used for electronically commutating the BLDCM for reduced switching losses. The Sheppard-Taylor converter is designed to operate in continuous conduction mode to achieve an improved power quality at the ac mains for a wide range of speed control and supply voltage variation. The BLDCM drive is designed and its performance is simulated in a MATLAB/Simulink environment to achieve the power quality indices within the limits of the international power quality standard IEC-61000-3-2.

  8. The alkali metal thermoelectric converter /AMTEC/ - A new direct energy conversion technology for aerospace power

    NASA Technical Reports Server (NTRS)

    Bankston, C. P.; Cole, T.; Jones, R.; Ewell, R.

    1982-01-01

    A thermally regenerative electrochemical device for the direct conversion of heat to electrical energy, the alkali metal thermoelectric converter (AMTEC), is characterized by potential efficiencies on the order of 15-40% and possesses no moving parts, making it a candidate for space power system applications. Device conversion efficiency is projected on the basis of experimental voltage vs current curves exhibiting power densities of 0.7 W/sq cm and measured electrode efficiencies of up to 40%. Preliminary radiative heat transfer measurements presented may be used in an investigation of methods for the reduction of AMTEC parasitic radiation losses. AMTEC assumes heat input and rejection temperatures of 900-1300 K and 400-800 K, respectively. The working fluid is liquid sodium, and the porous electrode employed is of molybdenum.

  9. Design of an integrated thermoelectric generator power converter for ultra-low power and low voltage body energy harvesters aimed at ExG active electrodes

    NASA Astrophysics Data System (ADS)

    Ataei, Milad; Robert, Christian; Boegli, Alexis; Farine, Pierre-André

    2015-10-01

    This paper describes a detailed design procedure for an efficient thermal body energy harvesting integrated power converter. The procedure is based on the examination of power loss and power transfer in a converter for a self-powered medical device. The efficiency limit for the system is derived and the converter is optimized for the worst case scenario. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. Circuit blocks including pulse generators are implemented based on the system specifications and optimized converter working frequency. At this working condition, it has been demonstrated that the wide area capacitor of the voltage doubler, which provides high voltage switch gating, can be eliminated at the expense of wider switches. With this method, measurements show that 54% efficiency is achieved for just a 20 mV transducer output voltage and 30% of the chip area is saved. The entire electronic board can fit in one EEG or ECG electrode, and the electronic system can convert the electrode to an active electrode.

  10. Converting Limbo Lands to Energy-Generating Stations: Renewable Energy Technologies on Underused, Formerly Contaminated Sites

    SciTech Connect

    Mosey, G.; Heimiller, D.; Dahle, D.; Vimmerstedt, L.; Brady-Sabeff, L.

    2007-10-01

    This report addresses the potential for using 'Limbo Lands' (underused, formerly contaminated sites, landfills, brownfields, abandoned mine lands, etc. ) as sites for renewable energy generating stations.

  11. Ultracold neutron detectors based on 10B converters used in the qBounce experiments☆

    PubMed Central

    Jenke, Tobias; Cronenberg, Gunther; Filter, Hanno; Geltenbort, Peter; Klein, Martin; Lauer, Thorsten; Mitsch, Kevin; Saul, Heiko; Seiler, Dominik; Stadler, David; Thalhammer, Martin; Abele, Hartmut

    2013-01-01

    Gravity experiments with very slow, so-called ultracold neutrons connect quantum mechanics with tests of Newton's inverse square law at short distances. These experiments face a low count rate and hence need highly optimized detector concepts. In the frame of this paper, we present low-background ultracold neutron counters and track detectors with micron resolution based on a 10B converter. We discuss the optimization of 10B converter layers, detector design and concepts for read-out electronics focusing on high-efficiency and low-background. We describe modifications of the counters that allow one to detect ultracold neutrons selectively on their spin-orientation. This is required for searches of hypothetical forces with spin–mass couplings. The mentioned experiments utilize a beam-monitoring concept which accounts for variations in the neutron flux that are typical for nuclear research facilities. The converter can also be used for detectors, which feature high efficiencies paired with high spatial resolution of 1–2μm. They allow one to resolve the quantum mechanical wave function of an ultracold neutron bound in the gravity potential above a neutron mirror. PMID:25843998

  12. Buck-boost converter for simultaneous semi-active vibration control and energy harvesting for electromagnetic regenerative shock absorber

    NASA Astrophysics Data System (ADS)

    Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

    2014-04-01

    Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.

  13. Converting Limbo Lands to Energy-Generating Stations: Renewable Energy Technologies on Underused, Formerly Contaminated Sites

    EPA Science Inventory

    This report addresses the potential for using "Limbo Lands" as sites for renewable energy generating stations. Limbo Lands are considered as underused, formerly contaminated sites, and include former Superfund sites, landfills, brownfields, abandoned mine lands, former industrial...

  14. Wide-range 7-switch flying capacitor based dc-dc converter for point-of-load applications

    NASA Astrophysics Data System (ADS)

    Jain, Parth

    In this thesis a dc-dc converter referred to as the 7-switch flying capacitor (7SFC) based multi-level buck converter intended for point-of-load applications is presented. The 7SFC operates with the principle of "transformability" which allows it to run in several switching modes when paired with a digital controller. The mode is selected based on input and output conditions by estimating the highest efficiency mode. The 7SFC converter utilizes a flying capacitor, which for certain modes allows for a large reduction in switching losses, especially when the converter is operated with high-input voltages. Compared to the conventional 2-phase interleaved buck converter, the 7SFC is able to reduce the size of the output inductors and capacitor by 33%. The 7SFC discrete prototype is able to achieve efficiencies greater than 90% over the majority of the operating range.

  15. A method of neutron energy evaluation by using an imaging plate and cone-like acryl converters with a geometrical modulation concept

    NASA Astrophysics Data System (ADS)

    Nohtomi, A.; Sugiura, N.; Itoh, T.; Wakabayashi, G.; Sakae, T.; Terunuma, T.; Yabuta, K.; Tamura, M.; Fujibuchi, T.; Takata, T.; Kume, K.

    2011-03-01

    Cone-like acryl converters have been used for transforming the energy-distribution information of incident fast neutrons into the spatial-distribution information of recoil protons. The characteristics of neutron-proton conversion have been studied up to around 10 MeV by using an imaging plate (IP). A notable and interesting signal enhancement due to recoil protons generated in an acryl converter was observed on IP images for irradiation with a 252Cf source. Similar experiments were also performed in the radiation field of a research nuclear reactor and an accelerator-based neutron generator. A Monte Carlo calculation was carried out in order to understand the spatial distributions of the signal enhancement by recoil protons; these distributions promisingly involve the energy information of incident neutrons in principle. Consequently, it has been revealed that the neutron energy evaluation is surely possible by analyzing the spatial distributions of signal enhancement that is caused by recoil protons.

  16. High-resolution array imaging using teleseismic converted waves based on adjoint methods

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Chen, C.

    2011-12-01

    Seismic coda waves and converted phases have been used extensively to image detailed subsurface structures underneath seismic arrays, based on methods such as receiver functions, Kirchhoff migration and generalized Radon transform (GRT). Utilizing the same coda and converted waves, we propose to image both discontinuity interfaces and 3D velocity anomalies by combining full numerical simulations of wave propagation with adjoint methods recently adopted in global and regional tomography inversions. The `sensitivities' of these coda/converted waves to density, P and S velocities are calculated based on the interaction of the forward wave field that produces the main P phase, and the adjoint wave field generated by injecting the coda/converted phases at array stations as virtual sources, similar to the computation of isochrons in previous techniques. The density kernels generally highlight discontinuity interfaces and sharp velocity contrasts, while P and S velocity kernels provide hints to the update of volumetric velocity structures. The application of numerical solvers also allows the incorporation of 3D regional tomography models as background velocity models, providing better focusing of velocity anomalies. We show the feasibility of this technique on a synthetic case built based on the imaging geometry for Slave craton in the northwestern Canadian Shield by the POLARIS broadband seismic network. The main challenge of this technique lies in reproducing the forward wave field generated by tele-seismic sources in a limited simulation domain encompassing only local heterogeneous structures underneath array receivers. For simple homogeneous and layer-over-half-space background models, this can be solved by setting the incoming plane waves as initial conditions based on analytical formulae. For more sophisticated background models, a hybrid spectral-element solver is implemented by defining a fictitious boundary encompassing all local heterogeneities within the

  17. Sensorless load torque estimation and passivity based control of buck converter fed DC motor.

    PubMed

    Kumar, S Ganesh; Thilagar, S Hosimin

    2015-01-01

    Passivity based control of DC motor in sensorless configuration is proposed in this paper. Exact tracking error dynamics passive output feedback control is used for stabilizing the speed of Buck converter fed DC motor under various load torques such as constant type, fan type, propeller type, and unknown load torques. Under load conditions, sensorless online algebraic approach is proposed, and it is compared with sensorless reduced order observer approach. The former produces better response in estimating the load torque. Sensitivity analysis is also performed to select the appropriate control variables. Simulation and experimental results fully confirm the superiority of the proposed approach suggested in this paper. PMID:25893208

  18. 10 Gbit/s optical wavelength converter with a Brillouin scattering-based spectral filter.

    PubMed

    Granot, Er'el; Sternklar, Shmuel; Chayet, Haim; Ben-Ezra, Shalva; Narkiss, Niv; Shahar, Nir; Sher, Arieh; Tsadka, Sagie

    2005-08-10

    For the first time, to our knowledge, a highly robust, high-bit-rate (10 Gbit/s) wavelength converter that is based on a narrow Brillouin filter is reported. The conversion takes place in a semiconductor optical amplifier (SOA) in a cross-gain-phase process. The SOA operates in a weak-modulation mode, and the exiting signal undergoes a dc reduction with a narrow spectral filter. In our system we perform spectrally narrow filtering by using a long Brillouin grating. PMID:16114535

  19. Sensorless Load Torque Estimation and Passivity Based Control of Buck Converter Fed DC Motor

    PubMed Central

    Kumar, S. Ganesh; Thilagar, S. Hosimin

    2015-01-01

    Passivity based control of DC motor in sensorless configuration is proposed in this paper. Exact tracking error dynamics passive output feedback control is used for stabilizing the speed of Buck converter fed DC motor under various load torques such as constant type, fan type, propeller type, and unknown load torques. Under load conditions, sensorless online algebraic approach is proposed, and it is compared with sensorless reduced order observer approach. The former produces better response in estimating the load torque. Sensitivity analysis is also performed to select the appropriate control variables. Simulation and experimental results fully confirm the superiority of the proposed approach suggested in this paper. PMID:25893208

  20. Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications

    NASA Astrophysics Data System (ADS)

    Cao, Dong

    Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non

  1. Eu2+ and Eu3+ based "concentrated phosphors" as converters for UV LED light: two approaches and two new examples

    NASA Astrophysics Data System (ADS)

    Batentschuk, M.; Geisler, R.; Hum, J.; Iqbal, F.; Meister, F.; Osvet, A.; Stiegelschmitt, A.; Winnacker, A.

    2012-01-01

    The absolute majority of phosphors are composed of a host lattice and some percentage of an activator. At higher activator concentrations the concentration quenching occurs. However, there are phosphors in which only minor quenching of the emission occurs with increasing of the activator content. Based on the existence of two different valence states of the Eu ion (2+ and 3+), two approaches for the development of "concentrated phosphors", i.e. light emitting materials in which the activator ion is a main part of the crystal lattice, are discussed. In both approaches, reduced energy migration leading to the luminescence quenching is considered as a main condition to reach a high quantum efficiency of a concentrated phosphor. Two kinds of phosphors—Eu2+-doped alumosilicate and Eu3+-doped oxyfluoride—are used as an experimental basis for this discussion. Starting from the stoichiometric Ca_{1-x}Eux^{2+}Al2Si2O8 anorthite and Eu3+OF oxyfluorides, the non-stoichiometric powders with Eu^{2+}_{0.92}Al_{1.76}Si_{2.24}O8, Eu3+(O, F)2,35 and Eu3+(O, F)2,16 compositions were synthesized by a solid state reaction and investigated. It was shown that—in spite of the almost 100% Eu concentration—light converters with high quantum efficiency of more than 45% can be realized. A possible application of these materials as UV LED light converters for white light emitting diodes are discussed as well.

  2. User's manual: Computer-aided design programs for inductor-energy-storage dc-to-dc electronic power converters

    NASA Technical Reports Server (NTRS)

    Huffman, S.

    1977-01-01

    Detailed instructions on the use of two computer-aided-design programs for designing the energy storage inductor for single winding and two winding dc to dc converters are provided. Step by step procedures are given to illustrate the formatting of user input data. The procedures are illustrated by eight sample design problems which include the user input and the computer program output.

  3. Numerical modeling of the effects of wave energy converter characteristics on nearshore wave conditions

    DOE PAGESBeta

    Chang, G.; Ruehl, K.; Jones, C. A.; Roberts, J.; Chartrand, C.

    2015-12-24

    Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs formore » large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.« less

  4. Numerical modeling of the effects of wave energy converter characteristics on nearshore wave conditions

    SciTech Connect

    Chang, G.; Ruehl, K.; Jones, C. A.; Roberts, J.; Chartrand, C.

    2015-12-24

    Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs for large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.

  5. A continuous fluorescence resonance energy transfer angiotensin I-converting enzyme assay.

    PubMed

    Carmona, Adriana K; Schwager, Sylva L; Juliano, Maria A; Juliano, Luiz; Sturrock, Edward D

    2006-01-01

    Angiotensin I-converting enzyme (ACE) is involved in various physiological and physiopathological conditions; therefore, the measurement of its catalytic activity may provide essential clinical information. This protocol describes a sensitive and rapid procedure for determination of ACE activity using fluorescence resonance energy transfer (FRET) substrates containing o-aminobenzoic acid (Abz) as the fluorescent group and 2,4-dinitrophenyl (Dnp) as the quencher acceptor. Hydrolysis of a peptide bond between the donor/acceptor pair generates fluorescence that can be detected continuously, allowing quantitative measurement of the enzyme activity. The FRET substrates provide a useful tool for kinetic studies and for ACE determination in biological fluids and crude tissue extracts. An important benefit of this method is the use of substrates selective for the two active sites of the enzyme, namely Abz-SDK(Dnp)P-OH for N-domain, Abz-LFK(Dnp)-OH for C-domain and Abz-FRK(Dnp)P-OH for somatic ACE. This methodology can be adapted for determinations using a 96-well fluorescence plate reader. PMID:17487185

  6. A 3D MPI-Parallel GPU-accelerated framework for simulating ocean wave energy converters

    NASA Astrophysics Data System (ADS)

    Pathak, Ashish; Raessi, Mehdi

    2015-11-01

    We present an MPI-parallel GPU-accelerated computational framework for studying the interaction between ocean waves and wave energy converters (WECs). The computational framework captures the viscous effects, nonlinear fluid-structure interaction (FSI), and breaking of waves around the structure, which cannot be captured in many potential flow solvers commonly used for WEC simulations. The full Navier-Stokes equations are solved using the two-step projection method, which is accelerated by porting the pressure Poisson equation to GPUs. The FSI is captured using the numerically stable fictitious domain method. A novel three-phase interface reconstruction algorithm is used to resolve three phases in a VOF-PLIC context. A consistent mass and momentum transport approach enables simulations at high density ratios. The accuracy of the overall framework is demonstrated via an array of test cases. Numerical simulations of the interaction between ocean waves and WECs are presented. Funding from the National Science Foundation CBET-1236462 grant is gratefully acknowledged.

  7. Extremum seeking-based optimization of high voltage converter modulator rise-time

    SciTech Connect

    Scheinker, Alexander; Bland, Michael; Krstic, Miroslav; Audia, Jeff

    2013-02-01

    We digitally implement an extremum seeking (ES) algorithm, which optimizes the rise time of the output voltage of a high voltage converter modulator (HVCM) at the Los Alamos Neutron Science Center (LANSCE) HVCM test stand by iteratively, simultaneously tuning the first 8 switching edges of each of the three phase drive waveforms (24 variables total). We achieve a 50 μs rise time, which is reduction in half compared to the 100 μs achieved at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Considering that HVCMs typically operate with an output voltage of 100 kV, with a 60Hz repetition rate, the 50 μs rise time reduction will result in very significant energy savings. The ES algorithm will prove successful, despite the noisy measurements and cost calculations, confirming the theoretical results that the algorithm is not affected by noise whose frequency components are independent of the perturbing frequencies.

  8. Design of photon converter and photoneutron target for High power electron accelerator based BNCT.

    PubMed

    Rahmani, Faezeh; Seifi, Samaneh; Anbaran, Hossein Tavakoli; Ghasemi, Farshad

    2015-12-01

    An electron accelerator, ILU-14, with current of 10 mA and 100 kW in power has been considered as one of the options for neutron source in Boron Neutron Capture Therapy (BNCT). The final design of neutron target has been obtained using MCNPX to optimize the neutron production. Tungsten in strip shape and D2O in cylindrical form have been proposed as the photon converter and the photoneutron target, respectively. In addition calculation of heat deposition in the photon target design has been considered to ensure mechanical stability of target. The results show that about 8.37×10(12) photoneutron/s with average energy of 615 keV can be produced by this neutron source design. In addition, using an appropriate beam shaping assembly an epithermal neutron flux of the order of 1.24×10(8) cm(-2) s(-1) can be obtained for BNCT applications. PMID:26278347

  9. A new depth measuring method for stereo camera based on converted relative extrinsic parameters

    NASA Astrophysics Data System (ADS)

    Song, Xiaowei; Yang, Lei; Wu, Yuanzhao; Liu, Zhong

    2013-08-01

    This paper presents a new depth measuring method for the dual-view stereo camera based on the converted relative extrinsic parameters. The relative extrinsic parameters between left and right cameras, which obtained by the stereo camera calibration, can indicate the geometric relationships among the left principle point, right principle point and convergent point. Furthermore, the geometry which consists of the corresponding points and the object can be obtained by making conversion between the corresponding points and principle points. Therefore, the depth of the object can be calculated based on the obtained geometry. The correctness of the proposed method has been proved in 3ds Max, and the validity of the method has been verified on the binocular stereo system of flea2 cameras. We compared our experimental results with the popular RGB-D camera (e.g. Kinect). The comparison results show that our method is reliable and efficient, without epipolar rectification.

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

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, N.; Muthiah, Ramaswamy

    2012-01-01

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

  11. Impute DC link (IDCL) cell based power converters and control thereof

    DOEpatents

    Divan, Deepakraj M.; Prasai, Anish; Hernendez, Jorge; Moghe, Rohit; Iyer, Amrit; Kandula, Rajendra Prasad

    2016-04-26

    Power flow controllers based on Imputed DC Link (IDCL) cells are provided. The IDCL cell is a self-contained power electronic building block (PEBB). The IDCL cell may be stacked in series and parallel to achieve power flow control at higher voltage and current levels. Each IDCL cell may comprise a gate drive, a voltage sharing module, and a thermal management component in order to facilitate easy integration of the cell into a variety of applications. By providing direct AC conversion, the IDCL cell based AC/AC converters reduce device count, eliminate the use of electrolytic capacitors that have life and reliability issues, and improve system efficiency compared with similarly rated back-to-back inverter system.

  12. A Study of Energy Conversion Efficiency of a Savonius Type Wave Energy Converter System

    NASA Astrophysics Data System (ADS)

    Tutar, Mustafa; Erdem, Ceyhan

    In the present study, two-dimensional, two-phase and turbulent flow around a horizontal axis 3-bladed Savonius rotor is considered. Numerical wave tank (NWT) simulations based on FVM/FDM technique in association with volume of fluid (VOF) element method are performed for specified values of wave heights for no-rotor flow case. Once validated against the theoretical data, the numerical simulations are extended to investigate the overall performance of the turbine over a very large range of wave height conditions for the rotor-flow case.

  13. A compact polarization converter for silicon-based slot waveguides using a hybrid plasmonic effect

    NASA Astrophysics Data System (ADS)

    Xu, Yin; Xiao, Jinbiao; Sun, Xiaohan

    2014-08-01

    A compact polarization converter for silicon-based slot waveguides is proposed, in which a metal strip of silver (Ag) with a right-angled cross section located at the upper-right corner of the slot waveguide is embedded in its upper claddings. Owing to the characteristics of the introduced asymmetric hybrid plasmonic waveguide, the modal hybridness is highly enhanced and the optimal optical axis rotation angle, 45°, is realized by optimizing the location and size of the Ag, resulting in high polarization conversion efficiency (PCE). Numerical results show that a polarization converter of 15.2 μm in length, operating at a wavelength of 1.55 μm for TM-to-TE conversion, is achieved, where the PCE and insertion loss are 96.9% and 0.7 dB, respectively, and bandwidth with PCE >92% is ˜67 nm (from 1524 to 1591 nm), covering the entire C-band. Moreover, fabrication tolerances to the structural parameters and field evolution along the propagation distance are investigated.

  14. Broadband and wide-angle reflective polarization converter based on metasurface at microwave frequencies

    NASA Astrophysics Data System (ADS)

    Zhang, Linbo; Zhou, Peiheng; Chen, Haiyan; Lu, Haipeng; Xie, Jianliang; Deng, Longjiang

    2015-09-01

    We propose to realize a broadband and wide-angle reflective polarization converter in microwave regions. The proposed converter can convert a linearly polarized (LP) wave to its cross-polarized wave at three resonant frequencies. It can also convert the LP wave to a circularly polarized wave at other two resonant frequencies. Furthermore, the proposed converter can achieve broad bandwidth with incident angle up to 45°. The simulated and measured results are in agreement in the entire frequency regions, and the bandwidth of polarization conversion over 75 % can be obtained from 7.6 to 15.5 GHz under normal incidence and from 7.8 to 13.0 GHz under incident angle of 45°. The surface current distributions of the proposed converter are discussed to analyze the physical mechanism. The converter tolerance to wide angle of incidence and the broad bandwidth could be useful in the range of applications in the microwave regions.

  15. Detecting laser-range-finding signals in surveying converter lining based on wavelet transform

    NASA Astrophysics Data System (ADS)

    Li, Hongsheng; Yang, Xiaofei; Shi, Tielin; Yang, Shuzi

    1998-08-01

    The precision of the laser range finding subsystem has important influences on the performances of the whole measurement system applied to survey the steelmaking converter lining erosion state. In the system, the object of laser beams is some rough lighting surfaces in high temperature. the laser range finding signals to reach the microcomputer system would be submerged in intense disturb environments. Common laser range finding devices could not work normally. This paper presents a method based on the wavelet transform to test solving the problem. The idea of this method includes encoding the measuring signals, decomposing the encoded received signals of components in different frequency scales and time domains by the wavelet transform method, extracting the features of encoded signals according to queer points to confirm the arrival of signals, and accurately calculating out the measured distances. In addition, the method is also helpful to adopt some digital filter algorithms in time. It could make further in improvement on the precision.

  16. Design of a delay-locked-loop-based time-to-digital converter

    NASA Astrophysics Data System (ADS)

    Zhaoxin, Ma; Xuefei, Bai; Lu, Huang

    2013-09-01

    A time-to-digital converter (TDC) based on a reset-free and anti-harmonic delay-locked loop (DLL) circuit for wireless positioning systems is discussed and described. The DLL that generates 32-phase clocks and a cycle period detector is employed to avoid “false locking". Driven by multiphase clocks, an encoder detects pulses and outputs the phase of the clock when the pulse arrives. The proposed TDC was implemented in SMIC 0.18 μm CMOS technology, and its core area occupies 0.7 × 0.55 mm2. The reference frequency ranges from 20 to 150 MHz. An LSB resolution of 521 ps can be achieved by using a reference clock of 60 MHz and the DNL is less than ±0.75 LSB. It dissipates 31.5 mW at 1.8 V supply voltage.

  17. Photonic analog-to-digital converter based on the robust symmetrical number system

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Chi, Hao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

    2012-11-01

    A novel approach to realizing photonic analog-to-digital conversion with Gray-code-like property is proposed and demonstrated. Instead of using Mach-Zehnder modulators (MZMs) with different half-wave voltages, an array of MZMs with identical half-wave voltages are applied to realize quantization and encoding, which greatly simplifies the implementation. Multiple comparators with preset thresholds are applied at the output of each MZM to improve the number of bits. Through properly setting the bias voltages of the MZMs, a photonic analog to digital converter (ADC) based on the robust symmetrical number system (RSNS) coding method is realized. As an example, a 3-channel structure with maximum quantization level of 17 (corresponding to 4.09 bits) is investigated in detail. We show that the differential encoding technique can be applied in the proposed structure, which increases the equivalent number of bits of the ADC system.

  18. Optimization of few-mode-fiber based mode converter for mode division multiplexing transmission

    NASA Astrophysics Data System (ADS)

    Xie, Yiwei; Fu, Songnian; Zhang, Minming; Tang, M.; Shum, P.; Liu, Deming

    2013-10-01

    Few-mode-fiber (FMF) based mode division multiplexing (MDM) is a promising technique to further increase the transmission capacity of single mode fibers. We propose and numerically investigate a fiber-optical mode converter (MC) using long period gratings (LPGs) fabricated on the FMF by point-by-point CO2 laser inscription technique. In order to precisely excite three modes (LP01, LP11, and LP02), both untilted LPG and tilted LPG are comprehensively optimized through the length, index modulation depth, and tilt angle of the LPG in order to achieve a mode contrast ratio (MCR) of more than 20 dB with less wavelength dependence. It is found that the proposed MCs have obvious advantages of high MCR, low mode crosstalk, easy fabrication and maintenance, and compact size.

  19. Demonstration of a 3-bit optical digital-to-analog converter based on silicon microring resonators.

    PubMed

    Yang, Lin; Ding, Jianfeng; Chen, Qiaoshan; Zhou, Ping; Zhang, Fanfan; Zhang, Lei

    2014-10-01

    We propose an N-bit optical digital-to-analog converter based on silicon microring resonators (MRRs), which can transform an N-bit electrical digital signal to an optical analog signal. A 3-bit optical digital-to-analog convertor is fabricated as proof of concept through a CMOS-compatible process on a silicon-on-insulator platform. The silicon MRRs are modulated through the electric-field-induced carrier injection in forward biased PN junctions embedded in the ring waveguides. The electro-optical 3-dB bandwidths of the silicon MRRs are approximately 800 MHz. The device works well at a speed of 500  MSample/s under driving voltage swings of 0.75 V. PMID:25360972

  20. Improvement of photovoltaic pumping systems based on standard frequency converters by means of programmable logic controllers

    SciTech Connect

    Fernandez-Ramos, Jose; Narvarte-Fernandez, Luis; Poza-Saura, Fernando

    2010-01-15

    Photovoltaic pumping systems (PVPS) based on standard frequency converters (SFCs) are currently experiencing a growing interest in pumping programmes implemented in remote areas because of their high performance in terms of component reliability, low cost, high power range and good availability of components virtually anywhere in the world. However, in practical applications there have appeared a number of problems related to the adaptation of the SFCs to the requirements of the photovoltaic pumping systems (PVPS). Another disadvantage of dedicated PVPS is the difficulty in implementing maximum power point tracking (MPPT). This paper shows that these problems can be solved through the addition of a basic industrial programmable logic controller (PLC) to the system. This PLC does not increase the cost and complexity of the system, but improves the adaptation of the SFC to the photovoltaic pumping system, and increases the overall performance of the system. (author)

  1. Converting a rule-based expert system into a belief network.

    PubMed

    Korver, M; Lucas, P J

    1993-01-01

    The theory of belief networks offers a relatively new approach for dealing with uncertain information in knowledge-based (expert) systems. In contrast with the heuristic techniques for reasoning with uncertainty employed in many rule-based expert systems, the theory of belief networks is mathematically sound, based on techniques from probability theory. It therefore seems attractive to convert existing rule-based expert systems into belief networks. In this article we discuss the design of a belief network reformulation of the diagnostic rule-based expert system HEPAR. For the purpose of this experiment we have studied several typical pieces of medical knowledge represented in the HEPAR system. It turned out that, due to the differences in the type of knowledge represented and in the formalism used to represent uncertainty, much of the medical knowledge required for building the belief network concerned could not be extracted from HEPAR. As a consequence, significant additional knowledge acquisition was required. However, the objects and attributes defined in the HEPAR system, as well as the conditions in production rules mentioning these objects and attributes, were useful for guiding the selection of the statistical variables for building the belief network. The mapping of objects and attributes in HEPAR to statistical variables is discussed in detail. PMID:8289533

  2. Analysis of the impacts of Wave Energy Converter arrays on the nearshore wave climate in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    O'Dea, A.; Haller, M. C.

    2013-12-01

    As concerns over the use of fossil fuels increase, more and more effort is being put into the search for renewable and reliable sources of energy. Developments in ocean technologies have made the extraction of wave energy a promising alternative. Commercial exploitation of wave energy would require the deployment of arrays of Wave Energy Converters (WECs) that include several to hundreds of individual devices. Interactions between WECs and ocean waves result in both near-field and far-field changes in the incident wave field, including a significant decrease in wave height and a redirection of waves in the lee of the array, referred to as the wave shadow. Nearshore wave height and direction are directly related to the wave radiation stresses that drive longshore currents, rip currents and nearshore sediment transport, which suggests that significant far-field changes in the wave field due to WEC arrays could have an impact on littoral processes. The goal of this study is to investigate the changes in nearshore wave conditions and radiation stress forcing as a result of an offshore array of point-absorber type WECs using a nested SWAN model, and to determine how array size, configuration, spacing and distance from shore influence these changes. The two sites of interest are the Northwest National Marine Renewable Energy Center (NNMREC) test sites off the coast of Newport Oregon, the North Energy Test Site (NETS) and the South Energy Test Site (SETS). NETS and SETS are permitted wave energy test sites located approximately 4 km and 10 km offshore, respectively. Twenty array configurations are simulated, including 5, 10, 25, 50 and 100 devices in two and three staggered rows in both closely spaced (three times the WEC diameter) and widely spaced (ten times the WEC diameter) arrays. Daily offshore wave spectra are obtained from a regional WAVEWATCH III hindcast for 2011, which are then propagated across the continental shelf using SWAN. Arrays are represented in SWAN

  3. Power Quality Improvement in Bridgeless Ac-Dc Converter Based Multi-output Switched Mode Power Supply

    NASA Astrophysics Data System (ADS)

    Singh, Shihka; Singh, Bhim; Bhuvaneswari, G.; Bist, Vashist

    2014-12-01

    Computer power supplies are required to have multiple isolated regulated dc voltages with low ripple content and high input power factor at the utility interface. A dc-dc converter is used for obtaining these isolated multi-output dc voltages with excellent regulation. In this paper, a non-isolated ac-dc converter is proposed as the first stage converter to obtain a regulated dc output rather than using a simple uncontrolled diode bridge rectifier at the front end. A dc-dc converter is used at the second stage that has a high frequency transformer with multiple secondary windings to obtain different dc voltage levels at the output. The proposed bridgeless converter based power supply is designed using fundamental design equations, and different component values are calculated. Extensive simulations are carried out to demonstrate the improved performance of the proposed bridgeless converter based multi-output computer power supply at varying source voltages and load conditions. Experimental validation of the power supply is carried on a developed hardware prototype, and the test results are compared with the simulated performance for design verification.

  4. Design of A 5-Bit Fully Parallel Analog to Digital Converter Using Common Gate Differrential Mos Pair-Based Comparator

    NASA Astrophysics Data System (ADS)

    Aytar, Oktay

    2015-09-01

    This paper presents a novel comparator structure based on the common gate differential MOS pair. The proposed comparator has been applied to fully parallel analog to digital converter (A/D converter). Furthermore, this article presents 5 bit fully parallel A/D Converter design using the cadence IC5141 design platform and NCSU(North Carolina State University) design kit with 0.18 μm CMOS technology library. The proposed fully parallel A/D converter consist of resistor array block, comparator block, 1-n decoder block and programmable logic array. The 1-n decoder block includes latch block and thermometer code circuit that is implemented using transmission gate based multiplexer circuit. Thus, sampling frequency and analog bandwidth are increased. The INL and DNL of the proposed fully parallel A/D converter are (0/ + 0.63) LSB and (-0.26/ + 0.31) LSB at a sampling frequency of 5 GS/s with an input signal of 50 MHz, respectively. The proposed fully parallel A/D Converter consumes 340 mW from 1.8 V supply.

  5. Experimental and theoretical investigation of semiconductor optical amplifier (SOA)-based all-optical wavelength converters

    NASA Astrophysics Data System (ADS)

    Dailey, James M.

    evident in the gain. We also discuss our work in optimizing SOA-based all-optical wavelength converters. We compare the use of passive Mach-Zehnder interferometer (AMZI) and Gaussian bandpass filters to optimize the wavelength-converted output eye quality. We conclude that the Gaussian filters provide superior signal quality, but with much lower output power. We also investigate the optimization of an active AMZI through the careful design of the power splitters. We numerically demonstrate significant and robust improvements in eye quality using our design rules, including increases of 21.5 and 4.6 dB in eye extinction and opening.

  6. Development of MEMS based pyroelectric thermal energy harvesters

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

    2011-06-01

    The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.

  7. Ovalis TAH: development and in vitro testing of a new electromechanical energy converter for a total artificial heart.

    PubMed

    Sauer, I M; Frank, J; Spiegelberg, A; Bücherl, E S

    2000-01-01

    A new electromechanical energy converting system has been developed to yield an efficient and durable orthotopic total artificial heart (TAH). The energy converter we developed transforms the unidirectional rotational motion of the motor into a longitudinal forward-reverse movement of an internal geared oval, linked directly to pusher plates on both sides. To ensure a permanent positive connection between the drive gear and the internally geared wheel, a ball bearing runs inside an oval shaped guide track. Motor, gear unit, and conical pusher plates are seated between alternately ejecting and filling ventricles. The unidirectional motion of the brushless DC motor affords easier motor control, reduces energy demand, and ensures longer life of the motor when compared with a bidirectional motion system. In vitro testing has been performed on a mock circulation loop. The overall system efficiency of the TAH Ovalis was 27-39% (mean, 36%) for the pump output range of 2-7 L/min. The maximum output of 7 L/min can be obtained with a pump rate of 130 min(-1) and an afterload pressure of 140 mm Hg. For an average sized human with a mean cardiac output of 6 L/min at a mean aortic pressure of 120 mm Hg, 5 watts of input power would be required. The size of the prototype is 560 cm3, the weight is 950 g. Our first in vitro studies demonstrated the excellent efficiency and pump performance of this new electromechanical energy converter. The results prove the feasibility of this new concept's use as an energy converter for a total artificial heart. PMID:11110274

  8. Performance characteristics of a combination solar photovoltaic heat engine energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  9. One-bit digital-to-analog converter based on rapid single flux quantum circuit

    NASA Astrophysics Data System (ADS)

    Hirayama, F.; Maezawa, M.; Suzuki, M.

    2007-10-01

    Rapid single flux quantum digital-to-analog (D/A) converters which synthesize arbitrary waveforms with metrological accuracy are under development. We propose a 1-bit RSFQ D/A converter which is expected to operate at higher sampling frequencies than the multi-bit converter and is suitable for multi-chip operation to achieve the output voltages exceeding 100 mV. Calculations of the noise power and the attenuation of the signal suggested that the rms error in a 10 kHz sine wave synthesized by the 1-bit converter with a third-order low-pass filter can be smaller than 10-7 at the sampling frequency of 100 MHz. A prototype 1-bit D/A converter was fabricated and the generation of dc voltages was confirmed as expected.

  10. Implementing Nonlinear Buoyancy and Excitation Forces in the WEC-Sim Wave Energy Converter Modeling Tool: Preprint

    SciTech Connect

    Lawson, M.; Yu, Y. H.; Nelessen, A.; Ruehl, K.; Michelen, C.

    2014-05-01

    Wave energy converters (WECs) are commonly designed and analyzed using numerical models that combine multi-body dynamics with hydrodynamic models based on the Cummins Equation and linearized hydrodynamic coefficients. These modeling methods are attractive design tools because they are computationally inexpensive and do not require the use of high performance computing resources necessitated by high-fidelity methods, such as Navier Stokes computational fluid dynamics. Modeling hydrodynamics using linear coefficients assumes that the device undergoes small motions and that the wetted surface area of the devices is approximately constant. WEC devices, however, are typically designed to undergo large motions in order to maximize power extraction, calling into question the validity of assuming that linear hydrodynamic models accurately capture the relevant fluid-structure interactions. In this paper, we study how calculating buoyancy and Froude-Krylov forces from the instantaneous position of a WEC device (referred to as instantaneous buoyancy and Froude-Krylov forces from herein) changes WEC simulation results compared to simulations that use linear hydrodynamic coefficients. First, we describe the WEC-Sim tool used to perform simulations and how the ability to model instantaneous forces was incorporated into WEC-Sim. We then use a simplified one-body WEC device to validate the model and to demonstrate how accounting for these instantaneously calculated forces affects the accuracy of simulation results, such as device motions, hydrodynamic forces, and power generation.

  11. Liquid metal thermal electric converter

    DOEpatents

    Abbin, Joseph P.; Andraka, Charles E.; Lukens, Laurance L.; Moreno, James B.

    1989-01-01

    A liquid metal thermal electric converter which converts heat energy to electrical energy. The design of the liquid metal thermal electric converter incorporates a unique configuration which directs the metal fluid pressure to the outside of the tube which results in the structural loads in the tube to be compressive. A liquid metal thermal electric converter refluxing boiler with series connection of tubes and a multiple cell liquid metal thermal electric converter are also provided.

  12. Qualitative model of a plasma photoelectric converter

    NASA Astrophysics Data System (ADS)

    Gorbunov, N. A.; Flamant, G.

    2009-01-01

    A converter of focused optical radiation into electric current is considered on the basis of the photovoltaic effect in plasmas. The converter model is based on analysis of asymmetric spatial distributions of charge particle number density and ambipolar potential in the photoplasma produced by external optical radiation focused in a heat pipe filled with a mixture of alkali vapor and a heavy inert gas. Energy balance in the plasma photoelectric converter is analyzed. The conditions in which the external radiation energy is effectively absorbed in the converter are indicated. The plasma parameters for which the energy of absorbed optical radiation is mainly spent on sustaining the ambipolar field in the plasma are determined. It is shown that the plasma photoelectric converter makes it possible to attain a high conversion efficiency for focused solar radiation.

  13. Intense antineutrino source based on a lithium converter. Proposal for a promising experiment for studying oscillations

    NASA Astrophysics Data System (ADS)

    Lyashuk, V. I.; Lutostansky, Yu. S.

    2016-03-01

    An intense electron-antineutrino source with a hard spectrum (E_{{{tilde v}_e}}^{max} = 13 MeV and < {{E_{{{tilde v}_e}}}} rangle = 6.5MeV) can be created on the basis of the short-lived isotope 8Li (β--decay, T 1/2 = 0.84 s) formed via the ( n, γ) activation of 7Li. In contrast to a reactor antineutrino spectrum whose uncertainty is large, particularly in the high-energy region {E_{{{tilde v}_e}}} > 6 MeV, which is experimentally relevant, the lithium {tilde v_e} spectrum is accurately determined. The proposed accelerator-driven experimental scheme with a neutron-producing target and a lithium converter as an intense {tilde v_e} source is an alternative to a nuclear reactor. The required amount of high-purity 7Li will be reduced in many times by using the suggested heavy-water LiOD solutions. A possible experiment involving the lithium source on search for sterile neutrinos in the mass region Δ m 2 ≥ 0.2 eV2 with a very high sensitivity to mixing-angle values down to sin2(2Θ) ≈ (7-10) × 10-4 at the 95% C.L. has been considered.

  14. Extremum seeking-based optimization of high voltage converter modulator rise-time

    DOE PAGESBeta

    Scheinker, Alexander; Bland, Michael; Krstic, Miroslav; Audia, Jeff

    2014-01-01

    We digitally implement an extremum seeking (ES) algorithm, which optimizes the rise time of the output voltage of a high voltage converter modulator (HVCM) at the Los Alamos Neutron Science Center (LANSCE) HVCM test stand by iteratively, simultaneously tuning the first 8 switching edges of each of the three phase drive waveforms (24 variables total). We achieve a 50 μs rise time, which is reduction in half compared to the 100 μs achieved at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Considering that HVCMs typically operate with an output voltage of 100 kV, with a 60Hz repetitionmore » rate, the 50 μs rise time reduction will result in very significant energy savings. The ES algorithm will prove successful, despite the noisy measurements and cost calculations, confirming the theoretical results that the algorithm is not affected by noise whose frequency components are independent of the perturbing frequencies.« less

  15. Spline-based high-accuracy piecewise-polynomial phase-to-sinusoid amplitude converters.

    PubMed

    Petrinović, Davor; Brezović, Marko

    2011-04-01

    We propose a method for direct digital frequency synthesis (DDS) using a cubic spline piecewise-polynomial model for a phase-to-sinusoid amplitude converter (PSAC). This method offers maximum smoothness of the output signal. Closed-form expressions for the cubic polynomial coefficients are derived in the spectral domain and the performance analysis of the model is given in the time and frequency domains. We derive the closed-form performance bounds of such DDS using conventional metrics: rms and maximum absolute errors (MAE) and maximum spurious free dynamic range (SFDR) measured in the discrete time domain. The main advantages of the proposed PSAC are its simplicity, analytical tractability, and inherent numerical stability for high table resolutions. Detailed guidelines for a fixed-point implementation are given, based on the algebraic analysis of all quantization effects. The results are verified on 81 PSAC configurations with the output resolutions from 5 to 41 bits by using a bit-exact simulation. The VHDL implementation of a high-accuracy DDS based on the proposed PSAC with 28-bit input phase word and 32-bit output value achieves SFDR of its digital output signal between 180 and 207 dB, with a signal-to-noise ratio of 192 dB. Its implementation requires only one 18 kB block RAM and three 18-bit embedded multipliers in a typical field-programmable gate array (FPGA) device. PMID:21507749

  16. Dual-band and high-efficiency polarization converter based on metasurfaces at microwave frequencies

    NASA Astrophysics Data System (ADS)

    Liu, Yajun; Xia, Song; Shi, Hongyu; Zhang, Anxue; Xu, Zhuo

    2016-06-01

    We present a dual-band and high-efficiency polarization converter in microwave regime. The proposed converter can convert a linearly polarized wave to its cross-polarized wave for two distinct bands: Ku (11.5-20.0 GHz) and Ka (28.8-34.0 GHz). It can also convert the linearly polarized wave to a circularly polarized wave at four other frequencies. The experimental results are in good agreement with simulation results for both frequency bands. The polarization conversion ratio is above 0.94 for the Ku-band and 0.90 for the Ka-band. Furthermore, the converter can achieve dual-band and high-efficiency polarization conversion over angles of incidence up to 45°. The converter is also polarization-selective in that only the x- and y-polarized waves can be converted. The physical mechanism of the dual-band polarization conversion effect is interpreted via decomposed electric field components that couple with different plasmon resonance modes of the structure.

  17. Prototype of Free Piston Stirling Converter for Household Use

    NASA Astrophysics Data System (ADS)

    Hoshino, Takeshi; Yoshihara, Shoichi; Akazawa, Teruyuki; Murao, Keiji

    A test model of a free piston Stirling engine (FPSE) converter was developed as a heat-to-electricity power converter for a demonstration of solar heat energy utilization at the Japan Aerospace Exploration Agency, for future aerospace applications. The target performance of the converter was 200 W electrical power output and 20% overall efficiency. A bench test of the converter was conducted to evaluate performance. The converter showed good performance as expected. In addition, the characteristics of the FPSE were investigated. Based on these achievements, prototype models of the FPSE for household use were designed and tested as part of a project supported by the New Energy and Industrial Technology Development Organization.

  18. Phase noise measurement of wideband microwave sources based on a microwave photonic frequency down-converter.

    PubMed

    Zhu, Dengjian; Zhang, Fangzheng; Zhou, Pei; Pan, Shilong

    2015-04-01

    An approach for phase noise measurement of microwave signal sources based on a microwave photonic frequency down-converter is proposed. Using the same optical carrier, the microwave signal under test is applied to generate two +1st-order optical sidebands by two stages of electro-optical modulations. A time delay is introduced between the two sidebands through a span of fiber. By beating the two +1st-order sidebands at a photodetector, frequency down-conversion is implemented, and phase noise of the signal under test can be calculated thereafter. The system has a very large operation bandwidth thanks to the frequency conversion in the optical domain, and good phase noise measurement sensitivity can be achieved since the signal degradation caused by electrical amplifiers is avoided. An experiment is carried out. The phase noise measured by the proposed system agrees well with that measured by a commercial spectrum analyzer or provided by the datasheet. A large operation bandwidth of 5-40 GHz is demonstrated using the proposed system. Moreover, good phase noise floor is achieved (-123  dBc/Hz at 1 kHz and -137  dBc/Hz at 10 kHz at 10 GHz), which is nearly constant over the full measurement range. PMID:25831324

  19. Americium-based oxides: Dense pellet fabrication from co-converted oxalates

    NASA Astrophysics Data System (ADS)

    Horlait, Denis; Lebreton, Florent; Gauthé, Aurélie; Caisso, Marie; Arab-Chapelet, Bénédicte; Picart, Sébastien; Delahaye, Thibaud

    2014-01-01

    Mixed oxides are used as nuclear fuels and are notably envisaged for future fuel cycles including plutonium and minor actinide recycling. In this context, processes are being developed for the fabrication of uranium-americium mixed-oxide compounds for transmutation. The purpose of these processes is not only the compliance with fuel specifications in terms of density and homogeneity, but also the simplification of the process for its industrialization as well as lowering dust generation. In this paper, the use of a U0.85Am0.15O2±δ powder synthesized by oxalate co-conversion as a precursor for dense fuel fabrications is assessed. This study notably focuses on sintering, which yielded pellets up to 96% of the theoretical density, taking advantage of the high reactivity and homogeneity of the powder. As-obtained pellets were further characterized to be compared to those obtained via processes based on the UMACS (Uranium Minor Actinide Conventional Sintering) process. This comparison highlights several advantages of co-converted powder as a precursor for simplified processes that generate little dust.

  20. High frequency converters for thermophotovoltaic applications

    SciTech Connect

    Fatemi, N.S.; Hoffman, R.W. Jr.; Lowe, R.A.; Jenkins, P.P.; Garverick, L.M.; Wilt, D.M.; Scheiman, D.

    1996-12-31

    Thermophotovoltaic (TPV) converters were developed and tested at the heat source operating temperature of 1,700 K. Rare-earth-doped yttrium aluminum garnet (YAG) and lutetium yttrium aluminum garnet (Lu, YAG) selective emitters, as well as a blackbody emitter, were coupled to InGaAs/InP photovoltaic (PV) cells and bandpass/infrared (IR) reflector filters. YAG-based selective emitters were adopted with Ho, Tm, and Er. PV cells had bandgaps of 0.51, 0.57, and 0.69 eV. Converter energy conversion efficiencies approaching 30%, as well as electrical output power densities near 2 W/cm{sup 2} were demonstrated. The overall performance of the filtered blackbody-based converter was found to be superior to the selective emitter YAG-based converters. The details of the measurements performed on the above converters and their individual components are presented.

  1. Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

    SciTech Connect

    Wanlass, Mark W.; Mascarenhas, Angelo

    2012-05-08

    Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

  2. Performance analysis of frequency up-converting energy harvesters for human locomotion

    NASA Astrophysics Data System (ADS)

    Anderson, Brittany; Wickenheiser, Adam

    2012-04-01

    Energy harvesting from human locomotion is a challenging problem because the low frequencies involved are incompatible with small, light-weight transducers. Furthermore, frequency variations during changing levels of activity greatly reduce the effectiveness of tuned resonant devices. This paper presents the performance analysis and parameter study of energy harvesters utilizing magnetic interactions for frequency up-conversion. Ferrous structures are used to periodically attract a magnetic tip mass during low-frequency oscillations, producing a series of impulses. This technique allows resonant structures to be designed for much higher natural frequencies and reduces the effects of excitation frequency variation. Measured vibrational data from several human activities are used to provide a time-varying, broadband input to the energy harvesting system and are recreated in a laboratory setting for experimental validation. Optimal load resistances are calculated under several assumptions including sinusoidal, white noise, and band-limited noise base excitations. These values are tested using simulations with real-world accelerations and compared to steady-state power optimization results. The optimal load is presented for each input signal, and an estimation of the maximum average power harvested under idealized conditions is given. The frequency up-conversion technique is compared to linear, resonant structures to determine the impact of the nonlinearities. Furthermore, an analysis is performed to study the discrepancies between the simulated results and the predicted performance derived from frequency response functions to determine the importance of transients.

  3. Base materials and technologies to maintain long service life and efficiency of thermionic converters and thermionic fuel elements

    NASA Astrophysics Data System (ADS)

    Nikolaev, Yury V.; Yastrebkov, Anotoly A.; Gontar, Alexander S.; Lapochkin, Nikolay V.; Belousenko, Alexander P.; Tsetskhladze, David L.

    2001-02-01

    It became possible to produce thermionic converters and thermionic fuel elements having a long-term service life and high efficiency only after developing new materials and processes of their production and treatment. This report present the characteristic of the level (achieved at present) of the base materials and technologies used in the State RI of SIA ``Lutch'' when producing TIC and TFE. .

  4. A new GTO-based single-phase to three-phase static converter for loco auxiliaries

    SciTech Connect

    Kumar, N.V.V.R.; Rajgopal, P.V.; Saxena, S.N.; Mondal, S.K.; Muni, B.P.; Vithal, J.V.R.

    1995-12-31

    Presently a rotating Arno converter is being used to drive the auxiliary motors inside the 25 kV AC locomotive. A GTO based Single-Phase to Three-Phase static converter has been developed to give a balanced three-phase ac supply for feeding the auxiliaries, in spite of wide voltage variations in the overhead catenary. This paper presents the salient features of the development, which was successfully tested inside a locomotive. The authors have successfully developed 180 kVA single-phase to three-phase static converter (hereafter referred to as static converter) for feeding the auxiliary motors in locomotives. The main advantage of the development is that the three-phase output voltage of converter (which is fed to all the three-phase induction motors) remains constant and perfectly balanced even with wide variations in the catenary voltage and under varying load conditions. The various other special features of the development are discussed in this paper.

  5. Preliminary Verification and Validation of WEC-Sim, an Open-Source Wave Energy Converter Design Tool: Preprint

    SciTech Connect

    Ruehl, K.; Michelen, C.; Kanner, S.; Lawson, M.; Yu, Y. H.

    2014-03-01

    To promote and support the wave energy industry, a wave energy converter (WEC) design tool, WEC-Sim, is being developed by Sandia National Laboratories and the National Renewable Energy Laboratory. In this paper, the WEC-Sim code is used to model a point absorber WEC designed by the U.S. Department of Energy's reference model project. Preliminary verification was performed by comparing results of the WEC-Sim simulation through a code-to-code comparison, utilizing the commercial codes ANSYS-AQWA, WaveDyn, and OrcaFlex. A preliminary validation of the code was also performed by comparing WEC-Sim simulation results to experimental wave tank tests.

  6. Feasibility study for convertible engine torque converter

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The feasibility study has shown that a dump/fill type torque converter has excellent potential for the convertible fan/shaft engine. The torque converter space requirement permits internal housing within the normal flow path of a turbofan engine at acceptable engine weight. The unit permits operating the engine in the turboshaft mode by decoupling the fan. To convert to turbofan mode, the torque converter overdrive capability bring the fan speed up to the power turbine speed to permit engagement of a mechanical lockup device when the shaft speed are synchronized. The conversion to turbofan mode can be made without drop of power turbine speed in less than 10 sec. Total thrust delivered to the aircraft by the proprotor, fan, and engine during tansient can be controlled to prevent loss of air speed or altitude. Heat rejection to the oil is low, and additional oil cooling capacity is not required. The turbofan engine aerodynamic design is basically uncompromised by convertibility and allows proper fan design for quiet and efficient cruise operation. Although the results of the feasibility study are exceedingly encouraging, it must be noted that they are based on extrapolation of limited existing data on torque converters. A component test program with three trial torque converter designs and concurrent computer modeling for fluid flow, stress, and dynamics, updated with test results from each unit, is recommended.

  7. An intense NIR emission from Ca14Al10Zn6O35:Mn(4+),Yb(3+)via energy transfer for solar spectral converters.

    PubMed

    Lü, Wei; Jiao, Mengmeng; Shao, Baiqi; Zhao, Lingfei; Feng, Yang; You, Hongpeng

    2016-01-14

    To date, most current reports on the development and optimization of solar spectral converters have described the utilization of energy transfer among rare-earth ions. Here, we introduce non-rare-earth ion Mn(4+) to transfer energy to Yb(3+), which can exhibit strong near-infrared luminescence. It can harvest UV-blue photons and exhibits intense NIR emission of Yb(3+) around 1000 nm, perfectly matching the maximum spectral response of Si solar cells. It demonstrates for the first time that efficient energy transfer occurs with a decrease in the excited state lifetime and red photoluminescence (PL) from Mn(4+) with increasing Yb(3+) concentration. These results demonstrate that the Mn(4+) ions can be an efficient and direct sensitizer harvesting UV-blue photons. It could provide new avenues for developing harvesting Si-based solar cells. PMID:26608908

  8. Time-to-digital converter based on analog time expansion for 3D time-of-flight cameras

    NASA Astrophysics Data System (ADS)

    Tanveer, Muhammad; Nissinen, Ilkka; Nissinen, Jan; Kostamovaara, Juha; Borg, Johan; Johansson, Jonny

    2014-03-01

    This paper presents an architecture and achievable performance for a time-to-digital converter, for 3D time-of-flight cameras. This design is partitioned in two levels. In the first level, an analog time expansion, where the time interval to be measured is stretched by a factor k, is achieved by charging a capacitor with current I, followed by discharging the capacitor with a current I/k. In the second level, the final time to digital conversion is performed by a global gated ring oscillator based time-to-digital converter. The performance can be increased by exploiting its properties of intrinsic scrambling of quantization noise and mismatch error, and first order noise shaping. The stretched time interval is measured by counting full clock cycles and storing the states of nine phases of the gated ring oscillator. The frequency of the gated ring oscillator is approximately 131 MHz, and an appropriate stretch factor k, can give a resolution of ≍ 57 ps. The combined low nonlinearity of the time stretcher and the gated ring oscillator-based time-to-digital converter can achieve a distance resolution of a few centimeters with low power consumption and small area occupation. The carefully optimized circuit configuration achieved by using an edge aligner, the time amplification property and the gated ring oscillator-based time-to-digital converter may lead to a compact, low power single photon configuration for 3D time-of-flight cameras, aimed for a measurement range of 10 meters.

  9. Evaluation of battery converters based on 4. 8-MW fuel cell demonstrator inverter. Final report. [Contains brief glossary

    SciTech Connect

    Not Available

    1980-10-01

    Electrical power conditioning is a critical element in the development of advanced electrochemical energy storage systems. This program evaluates the use of existing self-commutated converter technology (as developed by the Power Systems Division of United Technologies for the 4.8-MW Fuel Cell Demonstrator) with modification for use in battery energy storage systems. The program consists of three parts: evaluation of the cost and performance of a self-commutated converter modified to maintain production commonality between battery and fuel cell power conditioners, demonstration of the principal characteristics required for the battery application in MW-scale hardware, and investigation of the technical requirements of operation isolated from the utility system. A power-conditioning system consisting of a self-commutated converter augmented with a phase-controlled rectifier was selected and a preliminary design, prepared. A principal factor in this selection was production commonality with the fuel cell inverter system. Additional types of augmentation, and the use of a self-commutated converter system without augmentation, were also considered. A survey of advanced battery manufacturers was used to establish the dc interface characteristics. The principal characteristics of self-commutated converter operation required for battery application were demonstrated with the aid of an available 0.5-MW development system. A survey of five REA and municipal utilities and three A and E firms was conducted to determine technical requirements for operation in a mode isolated from the utility. Definitive requirements for this application were not established because of the limited scope of this study. 63 figures, 37 tables.

  10. Angiotensin-Converting Enzyme Inhibitors and Active Tuberculosis: A Population-Based Study.

    PubMed

    Wu, Jiunn-Yih; Lee, Meng-Tse Gabriel; Lee, Si-Huei; Lee, Shih-Hao; Tsai, Yi-Wen; Hsu, Shou-Chien; Chang, Shy-Shin; Lee, Chien-Chang

    2016-05-01

    Numerous epidemiological data suggest that the use of angiotensin-converting enzyme inhibitors (ACEis) can improve the clinical outcomes of pneumonia. Tuberculosis (TB) is an airborne bacteria like pneumonia, and we aimed to find out whether the use of ACEis can decrease the risk of active TB.We conducted a nested case-control analysis by using a 1 million longitudinally followed cohort, from Taiwan national health insurance research database. The rate ratios (RRs) for TB were estimated by conditional logistic regression, and adjusted using a TB-specific disease risk score (DRS) with 71 TB-related covariates.From January, 1997 to December, 2011, a total of 75,536 users of ACEis, and 7720 cases of new active TB were identified. Current use (DRS adjusted RR, 0.87 [95% CI, 0.78-0.97]), but not recent and past use of ACEis, was associated with a decrease in risk of active TB. Interestingly, it was found that chronic use (>90 days) of ACEis was associated with a further decrease in the risk of TB (aRR, 0.74, [95% CI, 0.66-0.83]). There was also a duration response effect, correlating decrease in TB risk with longer duration of ACEis use. The decrease in TB risk was also consistent across all patient subgroups (age, sex, heart failure, cerebrovascular diseases, myocardial infraction, renal diseases, and diabetes) and patients receiving other cardiovascular medicine.In this large population-based study, we found that subjects with recent and chronic use of ACEis were associated with decrease in TB risk. PMID:27175655

  11. Characterization of U.S. Wave Energy Converter (WEC) Test Sites: A Catalogue of Met-Ocean Data.

    SciTech Connect

    Dallman, Ann Renee; Neary, Vincent Sinclair

    2014-10-01

    This report presents met - ocean data and wave energy characteristics at three U.S. wave energy converter (WEC) test and potential deployment sites . Its purpose is to enable the compari son of wave resource characteristics among sites as well as the select io n of test sites that are most suitable for a developer's device and that best meet their testing needs and objectives . It also provides essential inputs for the design of WEC test devices and planning WEC tests, including the planning of deployment and op eration s and maintenance. For each site, this report catalogues wave statistics recommended in the (draft) International Electrotechnical Commission Technical Specification (IEC 62600 - 101 TS) on Wave Energy Characterization, as well as the frequency of oc currence of weather windows and extreme sea states, and statistics on wind and ocean currents. It also provides useful information on test site infrastructure and services .

  12. 670-GHz Down- and Up-Converting HEMT-Based Mixers

    NASA Technical Reports Server (NTRS)

    Schlecht, Enrich T.; Chattopadhyay, Goutam; Lin, Robert H.; Sin, Seth; Deal, William; Rodriquez, Bryan; Bayuk, Brian; Leong, Kevin; Mei, Gerry

    2012-01-01

    A large category of scientific investigation takes advantage of the interactions of signals in the frequency range from 300 to 1,000 GHz and higher. This includes astronomy and atmospheric science, where spectral observations in this frequency range give information about molecular abundances, pressures, and temperatures of small-sized molecules such as water. Additionally, there is a minimum in the atmospheric absorption at around 670 GHz that makes this frequency useful for terrestrial imaging, radar, and possibly communications purposes. This is because 670 GHz is a good compromise for imaging and radar applications between spatial resolution (for a given antenna size) that favors higher frequencies, and atmospheric losses that favor lower frequencies. A similar trade-off applies to communications link budgets: higher frequencies allow smaller antennas, but incur a higher loss. All of these applications usually require converting the RF (radio frequency) signal at 670 GHz to a lower IF (intermediate frequency) for processing. Further, transmitting for communication and radar generally requires up-conversion from IF to the RF. The current state-of-the-art device for performing the frequency conversion is based on Schottky diode mixers for both up and down conversion in this frequency range for room-temperature operation. Devices that can operate at room temperature are generally required for terrestrial, military, and planetary applications that cannot tolerate the mass, bulk, and power consumption of cryogenic cooling. The technology has recently advanced to the point that amplifiers in the region up to nearly 1,000 GHz are feasible. Almost all of these have been based on indium phosphide pseudomorphic high-electron mobility transistors (pHEMTs), in the form of monolithic microwave integrated circuits (MMICs). Since the processing of HEMT amplifiers is quite differ en t from that of Schottky diodes, use of Schottky mixers requires separate MMICs for the mixers

  13. Multiple-band reflective polarization converter based on deformed F-shaped metamaterial

    NASA Astrophysics Data System (ADS)

    Li, He; Xiao, Boxun; Huang, Xiaojun; Yang, Helin

    2015-03-01

    A three-layered deformed F-shaped metamaterial reflective polarization converter (RPC) is proposed to realize linear and circular polarization conversions. The proposed F-shaped RPC can convert a linearly polarized wave to its cross-polarized wave at the four resonant frequencies. It also can convert the linearly polarized wave to a circularly polarized wave at the other four resonant frequencies. In addition, the proposed F-shaped RPC can maintain the same rational direction at the five resonant frequencies when the incident is a circularly polarized wave and higher reflective coefficients can be obtained with the increase of the thickness of the dielectric layer. The simulated and measured results are in agreement in the entire frequency range, and the polarization conversion ratio is more than 85% for both linear and circular polarizations. Further simulations reveal that the polarization in the terahertz range can also be obtained by changing the thickness of the dielectric layer and the unit of the reflective polarization converter.

  14. Process of converting wind energy to elemental hydrogen and apparatus therefor

    SciTech Connect

    Salomon, R.E.

    1982-06-15

    A system is described for the conversion of the energy in the wind over oceanic regions into hydrogen which can be used as a supplement to or replacement for fossil fuels. The system is based on the use of modified sailing vessels which serve as water electrolysis plants. In operation, the wind propels the vessel through the water in the manner common to all sailing vessels except that the vessel in this system does not carry a mast and does not need the ballasting characteristic of conventional sailcraft. The propulsion of the vessel causes an immersed screw propeller to power an electromagnetic generator, the electric current from which electrolytically decomposes water into hydrogen and oxygen. The hydrogen is stored on board the vessel by allowing it to combine with suitable metal alloys such as the Fe-Ti alloys to form a hydride. The metal alloy hydride is stored in cannisters which are allowed to desorb their hydrogen at sea for use as a fuel source, or alternatively may be discharged ashore through pipelines at suitable intervals.

  15. Microminiature thermionic converters

    SciTech Connect

    King, Donald B.; Sadwick, Laurence P.; Wernsman, Bernard R.

    2001-09-25

    Microminiature thermionic converts (MTCs) having high energy-conversion efficiencies and variable operating temperatures. Methods of manufacturing those converters using semiconductor integrated circuit fabrication and micromachine manufacturing techniques are also disclosed. The MTCs of the invention incorporate cathode to anode spacing of about 1 micron or less and use cathode and anode materials having work functions ranging from about 1 eV to about 3 eV. Existing prior art thermionic converter technology has energy conversion efficiencies ranging from 5-15%. The MTCs of the present invention have maximum efficiencies of just under 30%, and thousands of the devices can be fabricated at modest costs.

  16. Estimation of the average junction temperature of two phosphors-converted white LED array based on (B + Y + R)/B ratio

    NASA Astrophysics Data System (ADS)

    Ke, Hong-Liang; Jing, Lei; Hao, Jian; Gao, Qun; Wang, Yao; Wang, Xiao-xun; Sun, Qiang; Xu, Zhi-Jun

    2016-07-01

    The method of non-contact measurement of the junction temperature (Tj) for phosphor-converted white LEDs based on W/B ratio, the ratio of the total radiant energy (W) to the radiant energy of blue emission (B), is verified firstly. It is shown that for two phosphors (Y3Al5O12:Ce and CaAlSiN3:Eu)-converted white LEDs, an significant uncertainty is introduced into the linearity between Tj and W/B ratio. Then a new approach is proposed which uses (B + Y + R)/B ratio, the ratio of the sum of radiant energies of blue emission (B), yellow emission (Y) and red emission (R) to the radiant energy of blue emission, to establish the correlation with Tj. Result shows that the proposed approach is of a satisfactory linearity between Tj and (B + Y + R)/B ratio, with R-square equal to 0.9906 and RMSE equal to 2.27 °C. It is also demonstrated that the proposed method is applicable to actual LED lighting system composed of large number of LEDs.

  17. A 96-channel FPGA-based time-to-digital converter

    SciTech Connect

    Bogdan, Mircea; Frisch, Henry; Heintz, Mary; Paramonov, Alexander; Sanders, Harold; Chappa, Steve; DeMaat, Robert; Klein, Rod; Miao, Ting; Phillips, Thomas J; Wilson, Peter

    2005-02-01

    We describe an FPGA-based, 96-channel, time-to-digital converter (TDC) intended for use with the Central Outer Tracker (COT) [1] in the CDF Experiment [2] at the Fermilab Tevatron. The COT system is digitized and read out by 315 TDC cards, each serving 96 wires of the chamber. The TDC is physically configured as a 9U VME card. The functionality is almost entirely programmed in firmware in two Altera Stratix FPGA’s. The special capabilities of this device are the availability of 840 MHz LVDS inputs, multiple phase-locked clock modules, and abundant memory. The TDC system operates with an input resolution of 1.2 ns, a minimum input pulse width of 4.8 ns and a minimum separation of 4.8 ns between pulses. Each input can accept up to 7 hits per collision. The time-to-digital conversion is done by first sampling each of the 96 inputs in 1.2-ns bins and filling a circular memory; the memory addresses of logical transitions (edges) in the input data are then translated into the time of arrival and width of the COT pulses. Memory pipelines with a depth of 5.5 μs allow deadtime-less operation in the first-level trigger; the data are multiple-buffered to diminish deadtime in the second-level trigger. The complete process of edge-detection and filling of buffers for readout takes 12 μs. The TDC VME interface allows a 64-bit Chain Block Transfer of multiple boards in a crate with transfer-rates up to 47 Mbytes/sec. The TDC also contains a separately-programmed data path that produces prompt trigger data every Tevatron crossing. The trigger bits are clocked onto the P3 VME backplane connector with a 22-ns clock for transmission to the trigger. The full TDC design and multi-card test results are described. The physical simplicity ensures low-maintenance; the functionality being in firmware allows reprogramming for other applications.

  18. Design and performance of radioisotope space power systems based on OSC multitube AMTEC converter designs

    SciTech Connect

    Schock, A.; Noravian, H.; Or, C.

    1997-12-31

    This paper extends the analytical procedure described in another paper in these proceedings to analyze a variety of compact and light-weight OSC-designed radioisotope-heated generators. Those generators employed General Purpose Heat Source (GPHS) modules and a converter containing sixteen AMTEC cells of OSC`s revised five-tube design with enhanced cell wall reflectivity described in a companion paper in these proceedings. OSC found that the performance of the generator is primarily a function of the thermal insulation between the outside of the generator`s 16 cells and the inside of its wall. After examining a variety of insulation options, it was found that the generator`s performance is optimized by employing a hybrid insulation system, in which the space between the cells is filled with fibrous Min-K insulation, and the generator walls are lined with tapered (i.e., graded-length) multifoil insulation. The OSC design results in a very compact generator, with eight AMTEC cells on each end of the heat source stack. The choice of the five-tube cells makes it possible to expand the BASE tube diameter without increasing the cell diameter. This is important because the eight cells mate well with the stacked GPHS modules. The OSC generator design includes a compliant heat source support and preload arrangement, to hold the heat source modules together during launch, and to maintain thermal contact conductance at the generator`s interfaces despite creep relaxation of its housing. The BOM and EOM (up to 15 years) performances of the revised generators were analyzed for two and three GPHS modules, both for fresh fuel and for aged fuel left over from a spare RTG (Radioisotope Thermoelectric Generator) fueled in 1982. The resulting power outputs were compared with JPL`s latest EOM power demand goals for the Pluto Express and Europa Orbiter missions, and with the generic goals of DOE`s Advanced Radioisotope Power System (ARPS) study. The OSC AMTEC designs yielded system

  19. A non-resonant, frequency up-converted electromagnetic energy harvester from human-body-induced vibration for hand-held smart system applications

    NASA Astrophysics Data System (ADS)

    Halim, Miah A.; Park, Jae Y.

    2014-03-01

    We present a non-resonant, frequency up-converted electromagnetic energy harvester that generates significant power from human-body-induced vibration, e.g., hand-shaking. Upon excitation, a freely movable non-magnetic ball within a cylinder periodically hits two magnets suspended on two helical compression springs located at either ends of the cylinder, allowing those to vibrate with higher frequencies. The device parameters have been designed based on the characteristics of human hand-shaking vibration. A prototype has been developed and tested both by vibration exciter (for non-resonance test) and by manual hand-shaking. The fabricated device generated 110 μW average power with 15.4 μW cm-3 average power density, while the energy harvester was mounted on a smart phone and was hand-shaken, indicating its ability in powering portable hand-held smart devices from low frequency (<5 Hz) vibrations.

  20. Step-by-Step Design of an FPGA-Based Digital Compensator for DC/DC Converters Oriented to an Introductory Course

    ERIC Educational Resources Information Center

    Zumel, P.; Fernandez, C.; Sanz, M.; Lazaro, A.; Barrado, A.

    2011-01-01

    In this paper, a short introductory course to introduce field-programmable gate array (FPGA)-based digital control of dc/dc switching power converters is presented. Digital control based on specific hardware has been at the leading edge of low-medium power dc/dc switching converters in recent years. Besides industry's interest in this topic, from…

  1. High resolution heterodyne interferometer based on time-to-digital converter.

    PubMed

    Wang, Fei; Long, Zhangcai; Zhang, Bin; Zhao, Meirong

    2012-04-01

    A new heterodyne interferometer is presented, which adopts time-to-digital converter (TDC) measuring the time intervals of zero crossings of heterodyne signal for phase demodulation. Thanks to the 0.1 ns time resolution of TDC and linear phase demodulation, it can achieve high resolution and avoids nonlinear measuring distortion in other indirect high precise phase demodulation methods, such as pulse width modulation (PWM) and in-phase∕quadrature (I∕Q) method. PMID:22559581

  2. High resolution heterodyne interferometer based on time-to-digital converter

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Long, Zhangcai; Zhang, Bin; Zhao, Meirong

    2012-04-01

    A new heterodyne interferometer is presented, which adopts time-to-digital converter (TDC) measuring the time intervals of zero crossings of heterodyne signal for phase demodulation. Thanks to the 0.1 ns time resolution of TDC and linear phase demodulation, it can achieve high resolution and avoids nonlinear measuring distortion in other indirect high precise phase demodulation methods, such as pulse width modulation (PWM) and in-phase/quadrature (I/Q) method.

  3. XTL Converter

    SciTech Connect

    Spurgeon, Steven R

    2015-10-07

    "XTL Converter" is a short Python script for electron microscopy simulation. The program takes an input crystal file in the VESTA *.XTL format and converts it to a text format readable by the multislice simulation program ìSTEM. The process of converting a crystal *.XTL file to the format used by the ìSTEM simulation program is quite tedious; it generally requires the user to select dozens or hundreds of atoms, rearranging and reformatting their position. Header information must also be reformatted to a specific style to be read by ìSTEM. "XTL Converter" simplifies this process, saving the user time and allowing for easy batch processing of crystals.

  4. XTL Converter

    Energy Science and Technology Software Center (ESTSC)

    2015-10-07

    "XTL Converter" is a short Python script for electron microscopy simulation. The program takes an input crystal file in the VESTA *.XTL format and converts it to a text format readable by the multislice simulation program ìSTEM. The process of converting a crystal *.XTL file to the format used by the ìSTEM simulation program is quite tedious; it generally requires the user to select dozens or hundreds of atoms, rearranging and reformatting their position. Headermore » information must also be reformatted to a specific style to be read by ìSTEM. "XTL Converter" simplifies this process, saving the user time and allowing for easy batch processing of crystals.« less

  5. Highly Selective Oxidation of Carbohydrates in an Efficient Electrochemical Energy Converter: Cogenerating Organic Electrosynthesis.

    PubMed

    Holade, Yaovi; Servat, Karine; Napporn, Teko W; Morais, Cláudia; Berjeaud, Jean-Marc; Kokoh, Kouakou B

    2016-02-01

    The selective electrochemical conversion of highly functionalized organic molecules into electricity, heat, and added-value chemicals for fine chemistry requires the development of highly selective, durable, and low-cost catalysts. Here, we propose an approach to make catalysts that can convert carbohydrates into chemicals selectively and produce electrical power and recoverable heat. A 100% Faradaic yield was achieved for the selective oxidation of the anomeric carbon of glucose and its related carbohydrates (C1-position) without any function protection. Furthermore, the direct glucose fuel cell (DGFC) enables an open-circuit voltage of 1.1 V in 0.5 m NaOH to be reached, a record. The optimized DGFC delivers an outstanding output power Pmax =2 mW cm(-2) with the selective conversion of 0.3 m glucose, which is of great interest for cogeneration. The purified reaction product will serve as a raw material in various industries, which thereby reduces the cost of the whole sustainable process. PMID:26777210

  6. New generation polyphase resonant converter-modulators for the Korean atomic energy research institute

    SciTech Connect

    Reass, William A; Baca, David M; Gribble, Robert F

    2009-01-01

    This paper will present operational data and performance parameters of the newest generation polyphase resonant high voltage converter modulator (HVCM) as developed and delivered to the KAERI 100 MeV ''PEFP'' accelerator [1]. The KAERI design realizes improvements from the SNS and SLAC designs [2]. To improve the IGBT switching performance at 20 kHz for the KAERI system, the HVCM utilizes the typical zero-voltage-switching (ZVS) at turn on and as well as artificial zero-current-switching (ZCS) at turn-off. The new technique of artificial ZCS technique should result in a 6 fold reduction of IGBT switching losses (3). This improves the HCVM conversion efficiency to better than 95% at full average power, which is 500 kW for the KAERI two klystron 105 kV, 50 A application. The artificial ZCS is accomplished by placing a resonant RLC circuit across the input busswork to the resonant boost transformer. This secondary resonant circuit provides a damped ''kick-back'' to assist in IGBT commutation. As the transformer input busswork is extremely low inductance (< 10 nH), the single RLC network acts like it is across each of the four IGBT collector-emitter terminals of the H-bridge switching network. We will review these topological improvements and the overall system as delivered to the KAERI accelerator and provide details of the operational results.

  7. The Effect of Converting to a U.S. Hydrogen Fuel Cell Vehicle Fleet on Emissions and Energy Use

    NASA Astrophysics Data System (ADS)

    Colella, W. G.; Jacobson, M. Z.; Golden, D. M.

    2004-12-01

    This study analyzes the potential change in emissions and energy use from replacing fossil-fuel based vehicles with hydrogen fuel cell vehicles. This study examines three different hydrogen production scenarios to determine their resultant emissions and energy usage: hydrogen produced via 1) steam reforming of methane, 2) coal gasification, or 3) wind electrolysis. The atmospheric model simulations require two primary sets of data: the actual emissions associated with hydrogen fuel production and use, and the corresponding reduction in emissions associated with reducing fossil fuel use. The net change in emissions is derived using 1) the U.S. EPA's National Emission Inventory (NEI) that incorporates several hundred categories of on-road vehicles and 2) a Process Chain Analysis (PCA) for the different hydrogen production scenarios. NEI: The quantity of hydrogen-related emission is ultimately a function of the projected hydrogen consumption in on-road vehicles. Data for hydrogen consumption from on-road vehicles was derived from the number of miles driven in each U.S. county based on 1999 NEI data, the average fleet mileage of all on-road vehicles, the average gasoline vehicle efficiency, and the efficiency of advanced 2004 fuel cell vehicles. PCA: PCA involves energy and mass balance calculations around the fuel extraction, production, transport, storage, and delivery processes. PCA was used to examine three different hydrogen production scenarios: In the first scenario, hydrogen is derived from natural gas, which is extracted from gas fields, stored, chemically processed, and transmitted through pipelines to distributed fuel processing units. The fuel processing units, situated in similar locations as gasoline refueling stations, convert natural gas to hydrogen via a combination of steam reforming and fuel oxidation. Purified hydrogen is compressed for use onboard fuel cell vehicles. In the second scenario, hydrogen is derived from coal, which is extracted from

  8. Photocapacitive image converter

    NASA Technical Reports Server (NTRS)

    Miller, W. E.; Sher, A.; Tsuo, Y. H. (Inventor)

    1982-01-01

    An apparatus for converting a radiant energy image into corresponding electrical signals including an image converter is described. The image converter includes a substrate of semiconductor material, an insulating layer on the front surface of the substrate, and an electrical contact on the back surface of the substrate. A first series of parallel transparent conductive stripes is on the insulating layer with a processing circuit connected to each of the conductive stripes for detecting the modulated voltages generated thereon. In a first embodiment of the invention, a modulated light stripe perpendicular to the conductive stripes scans the image converter. In a second embodiment a second insulating layer is deposited over the conductive stripes and a second series of parallel transparent conductive stripes perpendicular to the first series is on the second insulating layer. A different frequency current signal is applied to each of the second series of conductive stripes and a modulated image is applied to the image converter.

  9. A Particle-in-Cell Simulation for the Traveling Wave Direct Energy Converter (TWDEC) for Fusion Propulsion

    NASA Technical Reports Server (NTRS)

    Chap, Andrew; Tarditi, Alfonso G.; Scott, John H.

    2013-01-01

    A Particle-in-cell simulation model has been developed to study the physics of the Traveling Wave Direct Energy Converter (TWDEC) applied to the conversion of charged fusion products into electricity. In this model the availability of a beam of collimated fusion products is assumed; the simulation is focused on the conversion of the beam kinetic energy into alternating current (AC) electric power. The model is electrostatic, as the electro-dynamics of the relatively slow ions can be treated in the quasistatic approximation. A two-dimensional, axisymmetric (radial-axial coordinates) geometry is considered. Ion beam particles are injected on one end and travel along the axis through ring-shaped electrodes with externally applied time-varying voltages, thus modulating the beam by forming a sinusoidal pattern in the beam density. Further downstream, the modulated beam passes through another set of ring electrodes, now electrically oating. The modulated beam induces a time alternating potential di erence between adjacent electrodes. Power can be drawn from the electrodes by connecting a resistive load. As energy is dissipated in the load, a corresponding drop in beam energy is measured. The simulation encapsulates the TWDEC process by reproducing the time-dependent transfer of energy and the particle deceleration due to the electric eld phase time variations.

  10. Organic thermoelectric materials: emerging green energy materials converting heat to electricity directly and efficiently.

    PubMed

    Zhang, Qian; Sun, Yimeng; Xu, Wei; Zhu, Daoben

    2014-10-29

    The abundance of solar thermal energy and the widespread demands for waste heat recovery make thermoelectric generators (TEGs) very attractive in harvesting low-cost energy resources. Meanwhile, thermoelectric refrigeration is promising for local cooling and niche applications. In this context there is currently a growing interest in developing organic thermoelectric materials which are flexible, cost-effective, eco-friendly and potentially energy-efficient. In particular, the past several years have witnessed remarkable progress in organic thermoelectric materials and devices. In this review, thermoelectric properties of conducting polymers and small molecules are summarized, with recent progresses in materials, measurements and devices highlighted. Prospects and suggestions for future research efforts are also presented. The organic thermoelectric materials are emerging candidates for green energy conversion. PMID:24687930

  11. Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers: Preprint

    SciTech Connect

    Li, Y.; Yu, Y. H.

    2012-05-01

    During the past few decades, wave energy has received significant attention among all ocean energy formats. Industry has proposed hundreds of prototypes such as an oscillating water column, a point absorber, an overtopping system, and a bottom-hinged system. In particular, many researchers have focused on modeling the floating-point absorber as the technology to extract wave energy. Several modeling methods have been used such as the analytical method, the boundary-integral equation method, the Navier-Stokes equations method, and the empirical method. However, no standardized method has been decided. To assist the development of wave energy conversion technologies, this report reviews the methods for modeling the floating-point absorber.

  12. Fragment-based design for the development of N-domain-selective angiotensin-1-converting enzyme inhibitors.

    PubMed

    Douglas, Ross G; Sharma, Rajni K; Masuyer, Geoffrey; Lubbe, Lizelle; Zamora, Ismael; Acharya, K Ravi; Chibale, Kelly; Sturrock, Edward D

    2014-02-01

    ACE (angiotensin-1-converting enzyme) is a zinc metallopeptidase that plays a prominent role in blood pressure regulation and electrolyte homeostasis. ACE consists of two homologous domains that despite similarities of sequence and topology display differences in substrate processing and inhibitor binding. The design of inhibitors that selectively inhibit the N-domain (N-selective) could be useful in treating conditions of tissue injury and fibrosis due to build-up of N-domain-specific substrate Ac-SDKP (N-acetyl-Ser-Asp-Lys-Pro). Using a receptor-based SHOP (scaffold hopping) approach with N-selective inhibitor RXP407, a shortlist of scaffolds that consisted of modified RXP407 backbones with novel chemotypes was generated. These scaffolds were selected on the basis of enhanced predicted interaction energies with N-domain residues that differed from their C-domain counterparts. One scaffold was synthesized and inhibitory binding tested using a fluorogenic ACE assay. A molecule incorporating a tetrazole moiety in the P2 position (compound 33RE) displayed potent inhibition (K(i)=11.21±0.74 nM) and was 927-fold more selective for the N-domain than the C-domain. A crystal structure of compound 33RE in complex with the N-domain revealed its mode of binding through aromatic stacking with His388 and a direct hydrogen bond with the hydroxy group of the N-domain specific Tyr369. This work further elucidates the molecular basis for N-domain-selective inhibition and assists in the design of novel N-selective ACE inhibitors that could be employed in treatment of fibrosis disorders. PMID:24015848

  13. Double opposite-end tubesheet design for a thermovoltaic energy converter

    DOEpatents

    Ashcroft, John M.; Campbell, Brian C.; Depoy, David M.

    2000-01-01

    A method and apparatus for the direct conversion of energy by thermovoltaic energy conversion having first and second tubesheets, at least one photon emitter plate secured to and extending from the first tubesheet, at least one cold plate secured to and extending from the second tubesheet, a plurality of thermovoltaic cells disposed along oppositely disposed exterior surfaces of the cold plate, and means cooperating with the tubesheet for maintaining a vacuum between the photon emitter plate and the cold plate.

  14. Double opposite-end tubesheet design for a thermovoltaic energy converter

    SciTech Connect

    Ashcroft, John M.; Campbell, Brain C.; DePoy, David M.

    1997-12-01

    A method and apparatus are disclosed for the direct conversion of energy by thermovoltaic energy conversion having first and second tubesheets, at least one photon emitter plate secured to and extending from the first tubesheet, at least one cold plate secured to and extending from the second tubesheet, a plurality of thermovoltaic cells disposed along oppositely disposed exterior surfaces of the cold plate, and means cooperating with the tubesheet for maintaining a vacuum between the photon emitter plate and the cold plate.

  15. Solar-powered Stirling engines - Energy converters on earth and in space

    NASA Astrophysics Data System (ADS)

    Kleinwaechter, H.; Kleinwaechter, J.

    The development of the crankshaft Stirling engine has resulted in a machine suitable for energy conversion on earth and in space, using solar energy. The principle of the Stirling engine is discussed, the realization of the engine in a variety of applications is shown. The advantages of the free-piston design of the Stirling engine are addressed, and the engine's use in a receiver antenna for direct reception from satellites is considered.

  16. Modeling a thermionic energy converter using finite-difference time-domain particle-in-cell simulations

    SciTech Connect

    Lo, F. S.; Lee, T. H.; Lu, P. S.; Ragan-Kelley, B.; Minnich, A.; Lin, M. C.; Verboncoeur, J. P.

    2014-02-15

    A thermionic energy converter (TEC) is a static device that converts heat directly into electricity by boiling electrons off a hot emitter surface across a small inter-electrode gap to a cooler collector surface. The main challenge in TECs is overcoming the space charge limit, which limits the current transmitted across a gap of a given voltage and width. We have verified the feasibility of studying and developing a TEC using a bounded finite-difference time-domain particle-in-cell plasma simulation code, OOPD1, developed by Plasma Theory and Simulation Group, formerly at UC Berkeley and now at Michigan State University. In this preliminary work, a TEC has been modeled kinetically using OOPD1, and the accuracy has been verified by comparing with an analytically solvable case, giving good agreement. With further improvement of the code, one will be able to quickly and cheaply analyze space charge effects, and seek designs that mitigate the space charge effect, allowing TECs to become more efficient and cost-effective.

  17. Experimental detection of high-order or fractional orbital angular momentum of light based on a robust mode converter

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Zhang, Wuhong; Chen, Lixiang

    2016-03-01

    Based on our constructed robust π/2 mode converter, we report a concise yet high-efficient experiment to realize the detection of both high-order and fractional orbital angular momentum (OAM). The π/2 mode converter that consists of a pair of cylindrical lens is actually not new. However, our experiment shows clearly its excellent robustness, as we have detected the high-order OAM numbers up to ℓ = 100 carried by standard Laguerre-Gaussian (LG) modes. The observed patterns of two-dimensional optical lattices indicate that the radial index p of LG beams can be straightforwardly inferred as well. The versatility of the converter is also manifested by input modified LG beams carrying tunable fractional OAM, where we observe the output lattices exhibiting an interesting evolvement from Hermite-Gaussian mode HG m , 0 to its adjacent HG m + 1 , 0 . Numeric simulations based on OAM eigen-mode decomposition support the experimental results. Our demonstration has potential in both classical and quantum information applications where high OAM modes are needed.

  18. Two bit all-optical analog-to-digital converter based on nonlinear Kerr effect in 2D photonic crystals

    NASA Astrophysics Data System (ADS)

    Youssefi, Bahar; Moravvej-Farshi, Mohammad Kazem; Granpayeh, Nosrat

    2012-06-01

    We have demonstrated the performance of a novel design for a single wavelength 2-bit all-optical analog-to-digital converter (ADC). This converter consists of two high efficient channel drop filters with a coupled cavity-based wavelength selective reflector in a 2D photonic crystal with total length of 15.87 μm. The A/D conversion is achieved by using nonlinear Kerr effect in the cavities. The output ports switch to state '1' at different input power levels to generate unique states preferred for an ADC. This conversion is simulated by the finite difference time domain (FDTD) method for 5 different power levels. The proposed structure can function as a two-bit ADC with a 60 mW/μm input pulse and its maximum sampling rate is found to be ~ 45 GS/s.

  19. Development of a physically-based planar inductors VHDL-AMS model for integrated power converter design

    NASA Astrophysics Data System (ADS)

    Ammouri, Aymen; Ben Salah, Walid; Khachroumi, Sofiane; Ben Salah, Tarek; Kourda, Ferid; Morel, Hervé

    2014-05-01

    Design of integrated power converters needs prototype-less approaches. Specific simulations are required for investigation and validation process. Simulation relies on active and passive device models. Models of planar devices, for instance, are still not available in power simulator tools. There is, thus, a specific limitation during the simulation process of integrated power systems. The paper focuses on the development of a physically-based planar inductor model and its validation inside a power converter during transient switching. The planar inductor model remains a complex device to model, particularly when the skin, the proximity and the parasitic capacitances effects are taken into account. Heterogeneous simulation scheme, including circuit and device models, is successfully implemented in VHDL-AMS language and simulated in Simplorer platform. The mixed simulation results has been favorably tested and compared with practical measurements. It is found that the multi-domain simulation results and measurements data are in close agreement.

  20. Numerical analysis on the external characteristic of torque converter based on dynamic mesh

    NASA Astrophysics Data System (ADS)

    Su, H. S.; Yang, G. L.; Zhang, L. Q.; Zhang, J. F.; Li, R. N.

    2013-12-01

    For analysis of the flow field of torque converter's start operating performance, the paper established a mathematical model and simulated the numerical value of YJ series hydrodynamic torque converter. In view of the partial impact fluid and cavitation phenomenon in processes such as multiple flow area coupling algorithms the sliding mesh method cannot achieve the flow parameters real-time transfer problems between the impellers. The model, established by dynamic mesh technology, set pump wheel and turbine blade for the rotating part of dynamic mesh, pick up each iterative step of pump wheel and turbine by the size of moment through the function, and deposited it into the text file. Through calculating the changes of text data, we can judge whether the result is stable. Take the comprehensive consideration of the stability, accuracy and efficiency during the calculation, set pressure-velocity coupling algorithm as the SIMPLE algorithm, set spatial discrete format as the first order up stream format, set turbulence model as the RNG K-ε model, and realize the turbulence flow transient calculation of the hydrodynamic torque converter. Numerical simulation by the calculation was compared with the moment data from the experiments, the results show that the model established by dynamic mesh technology is more accurate and reliable. Thereafter, the pump wheel's start-up rotate speed increased from 0 to 1000r/min gradually, then remained constant. Through the analysis, we concluded as follows: the pump wheel 's moment increased gradually, the value of the turbine's moment was small, the flow increased slowly from the positive value in the early stage. Then the turbine's moment increased gradually, the flow changed into negative value until stable.

  1. Boost-Based MPPT Converter Topology Trade-Off for Space Applications

    NASA Astrophysics Data System (ADS)

    Garcia, O.; Alou, P.; Oliver, J. A.; Diaz, D.; Meneses, D.; Cobos, J. A.; Soto, A.; Lapena, E.; Rancano, J.

    2008-09-01

    High power and high voltage - 100V - power buses are often required not only in the frame of the telecommunication spacecrafts, but also for those scientific and interplanetary mission cases where a high user power load demand is driving the design of the power subsystem. On many cases, the use of Maximum Power Point Tracking (MPPT) is essential for an optimum power subsystem sizing.The adaptation to 100V of the existing MPPT concepts for 28V buses - like GOCE, ROSETTA, etc. - is not immediate, as happens in general terms with the upgrading of Power Conditioning Units from 28V to 50V and 100V. Moreover, for those cases where the solar array voltage is under the bus voltage, a step-up boost power cell is mandatory for the MPPT implementation.This paper will focus on the definition of the main performance characteristics that must have a converter power cell to fit the above mentioned application range. Starting with the establishment of the relevant trade-off parameters, in terms of power handling capability, input and output operational voltage ranges (both in nominal and emergency conditions), conducted emissions, bus capacitor and solar array output impedance considerations, several candidate topologies are analysed: conventional boost, interleaved DCM and CCM boost, two inductor boost, boost with ripple cancellation and boost with switch near ground. Some critical aspects like mass, efficiency and number of reactive and power switching elements are also covered.Special attention is paid to the feasibility of the design for the control loop that will govern the converter operation when forming part of a PCU, taking into account the effects of the RHPZ inherent to most of the boost converter topologies. Some of the candidate topologies where prototyped to demonstrate in the laboratory the performances identified during the analysis phase.

  2. Electromechanical modeling of a honeycomb core integrated vibration energy converter with increased specific power for energy harvesting applications

    NASA Astrophysics Data System (ADS)

    Chandrasekharan, Nataraj

    Innovation in integrated circuit technology along with improved manufacturing processes has resulted in considerable reduction in power consumption of electromechanical devices. Majority of these devices are currently powered by batteries. However, the issues posed by batteries, including the need for frequent battery recharge/replacement has resulted in a compelling need for alternate energy to achieve self-sufficient device operation or to supplement battery power. Vibration based energy harvesting methods through piezoelectric transduction provides with a promising potential towards replacing or supplementing battery power source. However, current piezoelectric energy harvesters generate low specific power (power-to-weight ratio) when compared to batteries that the harvesters seek to replace or supplement. In this study, the potential of integrating lightweight cellular honeycomb structures with existing piezoelectric device configurations (bimorph) to achieve higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of a conventional piezoelectric bimorph with honeycomb structures of the same material results in a significant increase in power-to-weight ratio of the piezoelectric harvester. In order to maximize the electrical response of vibration based power harvesters, the natural frequency of these harvesters is designed to match the input driving frequency. The commonly used technique of adding a tip mass is employed to lower the natural frequency (to match driving frequency) of both, solid and honeycomb substrate bimorphs. At higher excitation frequency, the natural frequency of the traditional solid substrate bimorph can only be altered (to match driving frequency) through a change in global geometric design parameters, typically achieved by increasing the thickness of the harvester. As a result, the size of the harvester is increased and can be disadvantageous

  3. Converter of laser beams with circular polarization to cylindrical vector beams based on anisotropic crystals

    NASA Astrophysics Data System (ADS)

    Paranin, Vyacheslav D.; Karpeev, Sergey V.; Kazanskiy, Nikolay L.; Krasnov, Andrey P.

    2016-03-01

    The optical system for converting laser beams with circular polarization to cylindrical vector beams on the basis of anisotropic crystals has been developed. The experimental research of beam formation quality has been carried out on the both polarization and structural characteristics. The research showed differences in the formation of the azimuthal and radial polarizations for Gaussian modes and Bessel beams. The boundaries of changes of the optical system parameters to form different types of polarizations with different amplitude and phase distributions have been identified.

  4. Metal Organic Vapor Phase Epitaxy of Monolithic Two-Color Light-Emitting Diodes Using an InGaN-Based Light Converter

    NASA Astrophysics Data System (ADS)

    Damilano, Benjamin; Kim-Chauveau, Hyonju; Frayssinet, Eric; Brault, Julien; Hussain, Sakhawat; Lekhal, Kaddour; Vennéguès, Philippe; De Mierry, Philippe; Massies, Jean

    2013-09-01

    Monolithic InGaN-based light-emitting diodes (LEDs) using a light converter fully grown by metal organic vapor phase epitaxy are demonstrated. The light converter, consisting of 10-40 InGaN/GaN quantum wells, is grown first, followed by a violet pump LED. The structure and growth conditions of the pump LED are specifically adapted to avoid thermal degradation of the light converter. Electroluminescence analysis shows that part of the pump light is absorbed by the light converter and reemitted at longer wavelength. Depending on the emission wavelength of the light converter, different LED colors are achieved. In particular, for red-emitting light converters, a color temperature of 2100 K corresponding to a tint between warm white and candle light is demonstrated.

  5. Enhanced Broadband Vibration Energy Harvesting Using a Multimodal Nonlinear Magnetoelectric Converter

    NASA Astrophysics Data System (ADS)

    Lin, Zhiming; Yang, Jin; Zhao, Jiangxin; Zhao, Nian; Liu, Jun; Wen, Yumei; Li, Ping

    2016-07-01

    In this work, we present a multimodal wideband vibration energy harvester designed to scavenge energy from ambient vibrations over a wide frequency range. The harvester consists of a folded cantilever, three magnetoelectric (ME) transducers, and two magnetic circuits. The folded cantilever enables multi-resonant response formed by bending of each stage, and the nonlinear magnetic forces acting on the folded cantilever beam allow further broadening of the frequency response. We also investigate the effects of the position of the ME transducer on the electrical output in order to achieve optimal performance. The experimental results show that the vibration energy harvester exhibited three resonance peaks in a range of 5 Hz to 30 Hz, a wider working bandwidth of 10.1 Hz, and a maximum average power value of 31.58 μW at an acceleration of 0.6 g (with g = 9.8 m/s2).

  6. Enhanced Broadband Vibration Energy Harvesting Using a Multimodal Nonlinear Magnetoelectric Converter

    NASA Astrophysics Data System (ADS)

    Lin, Zhiming; Yang, Jin; Zhao, Jiangxin; Zhao, Nian; Liu, Jun; Wen, Yumei; Li, Ping

    2016-05-01

    In this work, we present a multimodal wideband vibration energy harvester designed to scavenge energy from ambient vibrations over a wide frequency range. The harvester consists of a folded cantilever, three magnetoelectric (ME) transducers, and two magnetic circuits. The folded cantilever enables multi-resonant response formed by bending of each stage, and the nonlinear magnetic forces acting on the folded cantilever beam allow further broadening of the frequency response. We also investigate the effects of the position of the ME transducer on the electrical output in order to achieve optimal performance. The experimental results show that the vibration energy harvester exhibited three resonance peaks in a range of 5 Hz to 30 Hz, a wider working bandwidth of 10.1 Hz, and a maximum average power value of 31.58 μW at an acceleration of 0.6 g (with g = 9.8 m/s2).

  7. Investigation of Wave Energy Converter Effects on the Nearshore Environment: A Month-Long Study in Monterey Bay CA.

    SciTech Connect

    Roberts, Jesse D.; Chang, Grace; Magalen, Jason; Jones, Craig

    2014-09-01

    A modified version of an indust ry standard wave modeling tool, SNL - SWAN, was used to perform model simulations for hourly initial wave conditio ns measured during the month of October 2009. The model was run with an array of 50 wave energy converters (WECs) and compared with model runs without WECs. Maximum changes in H s were found in the lee of the WEC array along the angles of incident wave dire ction and minimal changes were found along the western side of the model domain due to wave shadowing by land. The largest wave height reductions occurred during observed typhoon conditions and resulted in 14% decreases in H s along the Santa Cruz shoreline . Shoreline reductions in H s were 5% during s outh swell wave conditions and negligible during average monthly wave conditions.

  8. Wave Energy Converter Effects on Wave Fields: Evaluation of SNL-SWAN and Sensitivity Studies in Monterey Bay CA.

    SciTech Connect

    Roberts, Jesse D.; Chang, Grace; Magalen, Jason; Jones, Craig

    2014-09-01

    A modified version of an indust ry standard wave modeling tool was evaluated, optimized, and utilized to investigate model sensitivity to input parameters a nd wave energy converter ( WEC ) array deployment scenarios. Wave propagation was investigated d ownstream of the WECs to evaluate overall near - and far - field effects of WEC arrays. The sensitivity study illustrate d that wave direction and WEC device type we r e most sensitive to the variation in the model parameters examined in this study . Generally, the changes in wave height we re the primary alteration caused by the presence of a WEC array. Specifically, W EC device type and subsequently their size directly re sult ed in wave height variations; however, it is important to utilize ongoing laboratory studies and future field tests to determine the most appropriate power matrix values for a particular WEC device and configuration in order to improve modeling results .

  9. Investigation of Wave Energy Converter Effects on Near-shore Wave Fields: Model Generation Validation and Evaluation - Kaneohe Bay HI.

    SciTech Connect

    Roberts, Jesse D.; Chang, Grace; Jones, Craig

    2014-09-01

    The numerical model, SWAN (Simulating WAves Nearshore) , was used to simulate wave conditions in Kaneohe Bay, HI in order to determine the effects of wave energy converter ( WEC ) devices on the propagation of waves into shore. A nested SWAN model was validated then used to evaluate a range of initial wave conditions: significant wave heights (H s ) , peak periods (T p ) , and mean wave directions ( MWD) . Differences between wave height s in the presence and absence of WEC device s were assessed at locations in shore of the WEC array. The maximum decrease in wave height due to the WEC s was predicted to be approximately 6% at 5 m and 10 m water depths. Th is occurred for model initiation parameters of H s = 3 m (for 5 m water depth) or 4 m (10 m water depth) , T p = 10 s, and MWD = 330deg . Subsequently, bottom orbital velocities were found to decrease by about 6%.

  10. Electrical energy converters for practical human total artificial hearts--an opinion in support of electropneumatic systems.

    PubMed

    Jarvik, R K

    1983-02-01

    Until recently, most artificial hearts have served as research tools to acquire further knowledge necessary ultimately to design practical systems for human use. Transcutaneous systems or percutaneous systems utilizing permanently implanted energy converters, batteries, and electronics packages have a number of substantial problems that would not exist if most system elements were kept outside the body. These problems include physiologic control, fit and fixation, foreign body infection, hermetic sealing, cable insulation and fatigue, inherent system complexity, stringent requirements for maintenance-free operation with long-term high reliability, and high cost. Percutaneous systems, particularly those in which only the blood pump is implanted, are an attractive choice for practical systems in the near future. A wearable, battery-powered electropneumatic total heart system should be developed. PMID:6838405

  11. Investigation of Wave Energy Converter Effects on Wave Fields: A Modeling Sensitivity Study in Monterey Bay CA.

    SciTech Connect

    Roberts, Jesse D.; Grace Chang; Jason Magalen; Craig Jones

    2014-08-01

    A n indust ry standard wave modeling tool was utilized to investigate model sensitivity to input parameters and wave energy converter ( WEC ) array deploym ent scenarios. Wave propagation was investigated d ownstream of the WECs to evaluate overall near - and far - field effects of WEC arrays. The sensitivity study illustrate d that b oth wave height and near - bottom orbital velocity we re subject to the largest pote ntial variations, each decreas ed in sensitivity as transmission coefficient increase d , as number and spacing of WEC devices decrease d , and as the deployment location move d offshore. Wave direction wa s affected consistently for all parameters and wave perio d was not affected (or negligibly affected) by varying model parameters or WEC configuration .

  12. Three-dimensional/two-dimensional convertible projection screen using see-through integral imaging based on holographic optical element.

    PubMed

    Yeom, Jiwoon; Jeong, Jinsoo; Jang, Changwon; Li, Gang; Hong, Keehoon; Lee, Byoungho

    2015-10-20

    We propose a 3D/2D convertible screen using a holographic optical element and angular multiplexing method of volume hologram. The proposed screen, named a multiplexed holographic optical element screen (MHOES), is composed of passive optical components, and displaying modes between 3D and 2D modes are converted according to projection directions. In a recording process, the angular multiplexing method by using two reference waves with different incidence angles enables the functions of 3D and 2D screens to be recorded in a single holographic material. Also, in order to avoid the bulky experimental setup due to adopting different projectors for the 3D and 2D modes, the projection part is realized based on a prism. The designed projection part enables the single projector to present 3D on 2D mode, where the 3D and 2D contents are simultaneously displayed in one scene, without active components. The optical characteristics of MHOES are experimentally analyzed, and displaying experiments with a full-color MHOES are presented in order to verify the 3D/2D convertibility and see-through properties. PMID:26560370

  13. Thermoelectric energy converter for generation of electricity from low-grade heat

    DOEpatents

    Jayadev, T.S.; Benson, D.K.

    1980-05-27

    A thermoelectric energy conversion device which includes a plurality of thermoelectric elements is described. A hot liquid is supplied to one side of each element and a cold liquid is supplied to the other side of each element. The thermoelectric generator may be utilized to produce power from low-grade heat sources such as ocean thermal gradients, solar ponds, and low-grade geothermal resources. (WHK)

  14. Converting campus waste into renewable energy – A case study for the University of Cincinnati

    SciTech Connect

    Tu, Qingshi; Zhu, Chao; McAvoy, Drew C.

    2015-05-15

    Highlights: • A case study to show the benefits of waste-to-energy projects at a university. • Evaluated the technical and economic feasibilities as well as GHG reduction. • A tool for other universities/communities to evaluate waste-to-energy projects. - Abstract: This paper evaluates the implementation of three waste-to-energy projects at the University of Cincinnati: waste cooking oil-to-biodiesel, waste paper-to-fuel pellets and food waste-to-biogas, respectively. The implementation of these waste-to-energy (WTE) projects would lead to the improvement of campus sustainability by minimizing waste management efforts and reducing GHG emissions via the displacement of fossil fuel usage. Technical and economic aspects of their implementation were assessed and the corresponding GHG reduction was estimated. Results showed that on-site implementation of these projects would: (1) divert 3682 L (974 gallons) of waste cooking oil to 3712 L (982 gallons) of biodiesel; (2) produce 138 tonnes of fuel pellets from 133 tonnes of waste paper (with the addition of 20.75 tonnes of plastics) to replace121 tonnes of coal; and (3) produce biogas that would be enough to replace 12,767 m{sup 3} natural gas every year from 146 tonnes of food waste. The economic analysis determined that the payback periods for the three projects would be 16 months for the biodiesel, 155 months for the fuel pellet, and 74 months for the biogas projects. The reduction of GHG emission from the implementation of the three WTE projects was determined to be 9.37 (biodiesel), 260.49 (fuel pellets), and 11.36 (biogas) tonnes of CO{sub 2}-eq per year, respectively.

  15. Pricing convertible bonds based on a multi-stage compound-option model

    NASA Astrophysics Data System (ADS)

    Gong, Pu; He, Zhiwei; Zhu, Song-Ping

    2006-07-01

    In this paper, we introduce the concept of multi-stage compound options to the valuation of convertible bonds (CBs). Rather than evaluating a nested high-dimensional integral that has arisen from the valuation of multi-stage compound options, we found that adopting the finite difference method (FDM) to solve the Black-Scholes equation for each stage actually resulted in a better numerical efficiency. By comparing our results with those obtained by solving the Black-Scholes equation directly, we can show that the new approach does provide an approximation approach for the valuation of CBs and demonstrate that it offers a great potential for a further extension to CBs with more complex structures such as those with call and/or put provisions.

  16. Coded output photonic A/D converter based on photonic crystal slow-light structures.

    PubMed

    Yu, Sunkyu; Koo, Sukmo; Park, Namkyoo

    2008-09-01

    A photonic analog-to-digital converter (PADC) utilizing a slow-light photonic crystal Mach-Zehnder interferometer (MZI) is proposed, to enable the optically coded output of a PADC with reduced device size and power consumption. Assuming an index modulation for the MZI on the Taylor's PADC structure, limiting factors in device size, speed, and effective number of bits are derived considering the signal transition time of the light and the slow light dispersion effects. Details of the device design and results of a time domain assessment of the device performance is described with discussions on the feasibility of sub-mm size, 20GS/s operation of the device having the ENOB (effective number of bits) > 5. PMID:18772986

  17. Contrast ratio enhancement in a saturable absorber-based photonic analog-to-digital converter

    NASA Astrophysics Data System (ADS)

    Hayduk, Michael J.; Bussjager, Rebecca J.; Johns, Steven T.; Gerhardstein, Cheryl M.; Wicks, Gary W.

    2002-07-01

    Optical processing techniques are expected to play a key role in the next generation of advanced high-speed analog- to-digital converters (ADCs). These techniques will alleviate the current limitations inherent in conventional electronic ADCs. We are currently developing a novel photonic ADC module that incorporates the use of semiconductor saturable absorbers to perform the data quantization at speeds in the tens of GHz regime. Results will be presented for the experimental material characterization of the semiconductor saturable absorbers used in the data conversion process. Enhancement of the contrast ratio of the saturable absorber between the 'on' state and the 'off' state can also be greatly enhanced by the use of an asymmetric Fabry-Perot etalon. Initial experimental results for a saturable absorber contained within an etalon will also be presented.

  18. An energy harvesting converter to power sensorized total human knee prosthesis

    NASA Astrophysics Data System (ADS)

    Luciano, V.; Sardini, E.; Serpelloni, M.; Baronio, G.

    2014-02-01

    Monitoring the internal loads acting in a total knee prosthesis (TKP) is fundamental aspect to improve their design. One of the main benefits of this improvement is the longer duration of the tibial inserts. In this work, an electromagnetic energy harvesting system, which is implantable in a TKP, is presented. This is conceived for powering a future implantable system that is able to monitor the loads (and, possibly, other parameters) that could influence the working conditions of a TKP in real-time. The energy harvesting system (EHS) is composed of two series of NdFeB magnets, positioned into each condyle, and a coil that is placed in a pin of the tibial insert and connected to an implantable power management circuit. The magnetic flux variation and the induced voltage are generated by the knee's motion. A TKP prototype has been realized in order to reproduce the knee mechanics and to test the EHS performance. In the present work, the experimental results are obtained by adopting a resistive load of 2.2 kΩ, in order to simulate a real implanted autonomous system with a current consumption of 850 µA and voltage of 2 V. The tests showed that, after 7 to 30 s of walking with a gait cycle frequency of about 1.0 Hz, the EHS can generate an energy of about 70 μJ, guaranteeing a voltage between 2 and 1.4 V every 7.6 s. With this prototype we can verify that it is possible to power for 16 ms a circuit having a power consumption of 1.7 mW every 7.6 s. The proposed generator is a viable solution to power an implanted electronic system that is conceived for measuring and transmitting the TKP load parameters.

  19. Effects of Wave Energy Converter (WEC) Arrays on Wave, Current, and Sediment Circulation

    NASA Astrophysics Data System (ADS)

    Ruehl, K.; Roberts, J. D.; Jones, C.; Magalen, J.; James, S. C.

    2012-12-01

    The characterization of the physical environment and commensurate alteration of that environment due to Wave Energy Conversion (WEC) devices, or arrays of devices, must be understood to make informed device-performance predictions, specifications of hydrodynamic loads, and environmental evaluations of eco-system responses (e.g., changes to circulation patterns, sediment dynamics, and water quality). Hydrodynamic and sediment issues associated with performance of wave-energy devices will primarily be nearshore where WEC infrastructure (e.g., anchors, piles) are exposed to large forces from the surface-wave action and currents. Wave-energy devices will be subject to additional corrosion, fouling, and wear of moving parts caused by suspended sediments in the water column. The alteration of the circulation and sediment transport patterns may also alter local ecosystems through changes in benthic habitat, circulation patterns, or other environmental parameters. Sandia National Laboratories is developing tools and performing studies to quantitatively characterize the environments where WEC devices may be installed and to assess potential affects to hydrodynamics and local sediment transport. The primary tools are wave, hydrodynamic, and sediment transport models. To ensure confidence in the resulting evaluation of system-wide effects, the models are appropriately constrained and validated with measured data where available. An extension of the US EPA's EFDC code, SNL-EFDC, provides a suitable platform for modeling the necessary hydrodynamics;it has been modified to directly incorporate output from a SWAN wave model of the region. Model development and results are presented. In this work, a model is exercised for Monterey Bay, near Santa Cruz where a WEC array could be deployed. Santa Cruz is located on the northern coast of Monterey Bay, in Central California, USA. This site was selected for preliminary research due to the readily available historical hydrodynamic data

  20. A terahertz-vibration to terahertz-radiation converter based on gold nanoobjects: a feasibility study

    PubMed Central

    2016-01-01

    Summary Background: The need for practical and adaptable terahertz sources is apparent in the areas of application such as early cancer diagnostics, nondestructive inspection of pharmaceutical tablets, visualization of concealed objects. We outline the operation principle and suggest the design of a simple appliance for generating terahertz radiation by a system of nanoobjects – gold nanobars (GNBs) or nanorings (GNRs) – irradiated by microwaves. Results: Our estimations confirm a feasibility of the idea that GNBs and GNRs irradiated by microwaves could become terahertz emitters with photon energies within the full width at half maximum of the longitudinal acoustic phononic DOS of gold (ca. 16–19 meV, i.e., 3.9–4.6 THz). A scheme of the terahertz radiation source is suggested based on the domestic microwave oven irradiating a substrate with multiple deposited GNBs or GNRs. Conclusion: The size of a nanoobject for optimal conversion is estimated to be approx. 3 nm (thickness) by approx. 100 nm (length of GNB, or along the GNR). This detailed prediction is open to experimental verification. An impact is expected onto further studies of interplay between atomic vibrations and electromagnetic waves in nanoobjects. PMID:27547615

  1. Demonstrating Electron Transfer and Nanotechnology: A Natural Dye-Sensitized Nanocrystalline Energy Converter

    NASA Astrophysics Data System (ADS)

    Smestad, Greg P.; Gratzel, Michael

    1998-06-01

    A unique solar cell fabrication procedure has been developed using natural anthocyanin dyes extracted from berries. It can be reproduced with a minimum amount of resources in order to provide an interdisciplinary approach for lower-division undergraduate students learning the basic principles of biological extraction, physical chemistry, and spectroscopy as well as environmental science and electron transfer. Electron transfer is the basis of the energetics that drives the processes of life on Earth, occurring in both the mitochondrial membranes of living cells and in the thylakoid membranes of photosynthetic cells of green plants and algae (1). Although we depend on the petroleum and agricultural products of this electron and energy transfer, one of the greatest challenges of the 21st century is that we have yet to create devices that can be used to tap directly into the ultimate source of this energy on an economic scale. An experimental lab procedure was therefore created in order to illustrate the connections between natural and man-made solar conversion within a three-hour lab period.

  2. Converting campus waste into renewable energy - a case study for the University of Cincinnati.

    PubMed

    Tu, Qingshi; Zhu, Chao; McAvoy, Drew C

    2015-05-01

    This paper evaluates the implementation of three waste-to-energy projects at the University of Cincinnati: waste cooking oil-to-biodiesel, waste paper-to-fuel pellets and food waste-to-biogas, respectively. The implementation of these waste-to-energy (WTE) projects would lead to the improvement of campus sustainability by minimizing waste management efforts and reducing GHG emissions via the displacement of fossil fuel usage. Technical and economic aspects of their implementation were assessed and the corresponding GHG reduction was estimated. Results showed that on-site implementation of these projects would: (1) divert 3682L (974 gallons) of waste cooking oil to 3712L (982 gallons) of biodiesel; (2) produce 138tonnes of fuel pellets from 133tonnes of waste paper (with the addition of 20.75tonnes of plastics) to replace121tonnes of coal; and (3) produce biogas that would be enough to replace 12,767m(3) natural gas every year from 146tonnes of food waste. The economic analysis determined that the payback periods for the three projects would be 16months for the biodiesel, 155months for the fuel pellet, and 74months for the biogas projects. The reduction of GHG emission from the implementation of the three WTE projects was determined to be 9.37 (biodiesel), 260.49 (fuel pellets), and 11.36 (biogas) tonnes of CO2-eq per year, respectively. PMID:25697388

  3. A Theory of Control for a Class of Electronic Power Processing Systems: Energy-Storage DC-To-DC Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Burns, W. W., III

    1977-01-01

    An analytically derived approach to the control of energy-storage dc-to-dc converters, which enables improved system performance and an extensive understanding of the manner in which this improved performance is accomplished, is presented. The control approach is derived from a state-plane analysis of dc-to-dc converter power stages which enables a graphical visualization of the movement of the system state during both steady state and transient operation. This graphical representation of the behavior of dc-to-dc converter systems yields considerable qualitative insight into the cause and effect relationships which exist between various commonly used converter control functions and the system performance which results from them.

  4. Note: A cubic electromagnetic harvester that convert vibration energy from all directions

    NASA Astrophysics Data System (ADS)

    Han, Mengdi; Qiu, Guolin; Liu, Wen; Meng, Bo; Zhang, Xiao-Sheng; Zhang, Haixia

    2014-07-01

    We investigate the output performance of a cubic harvester which can scavenge low-frequency vibration energy from all directions. By adjusting the size and shape of the inside magnets, higher induced voltages and output power can be achieved. The optimal magnet is found to be cubic shape with the length of 6.35 mm (25.6% volume ratio), which can generate 4.27 mV root mean square voltage and 2.45 μW average power at the frequency of 28.86 Hz and acceleration of 1.17 g. The device is also demonstrated as a self-powered tilt sensor by measuring induced voltages at different tilt angles.

  5. Technological cost-reduction pathways for attenuator wave energy converters in the marine hydrokinetic environment.

    SciTech Connect

    Bull, Diana L; Ochs, Margaret Ellen

    2013-09-01

    This report considers and prioritizes the primary potential technical costreduction pathways for offshore wave activated body attenuators designed for ocean resources. This report focuses on technical research and development costreduction pathways related to the device technology rather than environmental monitoring or permitting opportunities. Three sources of information were used to understand current cost drivers and develop a prioritized list of potential costreduction pathways: a literature review of technical work related to attenuators, a reference device compiled from literature sources, and a webinar with each of three industry device developers. Data from these information sources were aggregated and prioritized with respect to the potential impact on the lifetime levelized cost of energy, the potential for progress, the potential for success, and the confidence in success. Results indicate the five most promising costreduction pathways include advanced controls, an optimized structural design, improved power conversion, planned maintenance scheduling, and an optimized device profile.

  6. Interferometric wavelength converter operating at 10 Gb/s based on a monolithic-integrated photonic circuit

    NASA Astrophysics Data System (ADS)

    Rigo, C.; Coriasso, C.; Campi, D.; Stano, A.; Cacciatore, C.; Re, D.; Fornuto, G.; Soldani, D.; De Franceschi, R.; Ghiglieno, F.; Vallone, M.; Valenti, P.; Zucchelli, L.; Lupo, S.; Gambini, P.

    2000-02-01

    In this work we present a wavelength converter based on a Michelson interferometer. It is obtained by monolithic integration of two-semiconductor optical amplifiers with a passive waveguided X-coupler, incorporating turning mirrors. It operates in the 1.55 μm spectral window and allows the wavelength conversion of data streams up to 10 Gb/s, showing open-eye diagrams and extinction-ratio regeneration capabilities. Comparison of two structures with different active layers and their influence on the polarization sensitivity is also presented.

  7. A novel 40-Gb/s all-optical inverted wavelength converter based on a modified terahertz optical asymmetric demultiplexer

    NASA Astrophysics Data System (ADS)

    Huang, Xuetian; Ye, Peida; Zhang, Min; Wang, Ling

    2004-12-01

    A novel scheme for all-optical inverted wavelength conversion with 40-Gb/s pseudorandom bit sequences (PRBSs) based on a modified terahertz optical asymmetric demultiplexer (TOAD) is proposed. The performance of the proposed wavelength converter is analyzed in term of extinction ratio (ER) through numerical simulations. For a typical ER of 10 dB, some key characteristic parameters of the semiconductor optical amplifier (SOA) are designed. With the properly designed parameters, a high quality eye diagram is achievable, indicating that the amplitude fluctuation of the output signal is effectively reduced.

  8. A widely tunable wavelength converter based on nonlinear polarization rotation in a carbon-nanotube-deposited D-shaped fiber.

    PubMed

    Chow, K K; Yamashita, S; Song, Y W

    2009-04-27

    We demonstrate widely tunable wavelength conversion based on cross-phase modulation induced nonlinear polarization rotation in a carbon nanotubes (CNTs) deposited D-shaped fiber. A 5-centimeter-long CNT-deposited D-shaped fiber is used as the nonlinear medium for wavelength conversion of a 10 Gb/s non-return-to-zero signal. Wavelength tunable converted signal over 40 nm is obtained with around 2.5-dB power penalty in the bit-error-rate measurements. PMID:19399145

  9. Polarization beam splitters, converters and analyzers based on a metasurface composed of regularly arranged silicon nanospheres with controllable coupling strength.

    PubMed

    Xiang, Jin; Li, Jinxiang; Li, Hui; Zhang, Chengyun; Dai, Qiaofeng; Tie, Shaolong; Lan, Sheng

    2016-05-30

    A metasurface composed of regularly arranged silicon (Si) nanospheres (NSs) with coupling was investigated both theoretically and numerically based on the Mie theory, the simple Lorentz line shape model and the finite-difference time-domain technique. By deliberately controlling the coupling strength between Si NSs through the design of the lattice constants of a rectangular lattice, polarization beam splitters, converters and analyzers with good performance can be successfully constructed. A square lattice as well as a large incidence angle was employed to build the polarization beam splitters and converters. At an incidence angle of 80°, the polarization beam splitters can completely reflect the s-polarized light and transmit the p-polarized light in a wavelength region of 510-620 nm. For a circularly polarized light incident on the polarization converters, one can get s-polarized light in the reflection direction and p-polarized light in the transmission direction. For the polarization beam analyzers, a rectangular lattice with deliberately chosen lattice constants was employed and the transmissivity of a linearly polarized light can be continuously adjusted from 0 to ~0.90 by simply rotating the metasurface. We revealed that the broadening of either the electric dipole resonance or the magnetic dipole resonance or both of them, which is induced by the asymmetric coupling of Si NSs, is responsible for the modification in the transmissivity spectrum of the metasurface. Our findings provide a guideline for designing photonic devices based on the metasurfaces composed of Si NSs with controllable coupling strength. PMID:27410070

  10. Converting environmentally hazardous materials into clean energy using a novel nanostructured photoelectrochemical fuel cell

    SciTech Connect

    Gan, Yong X.; Gan, Bo J.; Clark, Evan; Su, Lusheng; Zhang, Lihua

    2012-09-15

    Highlights: ► A photoelectrochemical fuel cell has been made from TiO{sub 2} nanotubes. ► The fuel cell decomposes environmentally hazardous materials to produce electricity. ► Doping the anode with a transition metal oxide increases the visible light sensitivity. ► Loading the anode with a conducting polymer enhances the visible light absorption. -- Abstract: In this work, a novel photoelectrochemical fuel cell consisting of a titanium dioxide nanotube array photosensitive anode and a platinum cathode was made for decomposing environmentally hazardous materials to produce electricity and clean fuel. Titanium dioxide nanotubes (TiO{sub 2} NTs) were prepared via electrochemical oxidation of pure Ti in an ammonium fluoride and glycerol-containing solution. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO{sub 2} NTs were determined. The photosensitive anode made from the highly ordered TiO{sub 2} NTs has good photo-catalytic property, as proven by the decomposition tests on urea, ammonia, sodium sulfide and automobile engine coolant under ultraviolet (UV) radiation. To improve the efficiency of the fuel cell, doping the TiO{sub 2} NTs with a transition metal oxide, NiO, was performed and the photosensitivity of the doped anode was tested under visible light irradiation. It is found that the NiO-doped anode is sensitive to visible light. Also found is that polyaniline-doped photosensitive anode can harvest photon energy in the visible light spectrum range much more efficiently than the NiO-doped one. It is concluded that the nanostructured photoelectrochemical fuel cell can generate electricity and clean fuel by decomposing hazardous materials under sunlight.

  11. Multi-junction Thermophotovoltaic Converters Based on Dilute Nitride Superlattices Lattice Matched to InP

    NASA Astrophysics Data System (ADS)

    Bhusal, L.; Freundlich, A.

    2007-02-01

    Recently we have shown that by adjusting the thickness of individual sublayers and the nitrogen composition, strain balanced GaAs1-xNx/InAs1-yNy superlattices can be designed to be both lattice matched to InP and have effective bangaps in the desirable 0.4-0.65 eV range. The effect of insertion of such superlattice-like alloy within the intrinsic region of a 0.74 eV InGaAs p-i-n diode was also evaluated and it was shown that such a single junction device exhibits a photovoltaic response comparable to its lattice-mismatched 0.55 eV-InGaAs counterpart. In this work we have extended the approach to multi-junctions devices. Here two or more subcells with different effective bandgaps for the superlattice region are monolithically series connected. Maximum power output and performance of double, triple and quadruple junction TPV cells are evaluated as a function of the superlattice/cell design for a relatively low temperature black body emitters (1350K). The study stresses the potential of the proposed approach for a significant enhancement of TPV converter performance.

  12. Towards a Morse Code-Based Non-invasive Thought-to-Speech Converter

    NASA Astrophysics Data System (ADS)

    Nicolaou, Nicoletta; Georgiou, Julius

    This paper presents our investigations towards a non-invasive custom-built thought-to-speech converter that decodes mental tasks into morse code, text and then speech. The proposed system is aimed primarily at people who have lost their ability to communicate via conventional means. The investigations presented here are part of our greater search for an appropriate set of features, classifiers and mental tasks that would maximise classification accuracy in such a system. Here Autoregressive (AR) coefficients and Power Spectral Density (PSD) features have been classified using a Support Vector Machine (SVM). The classification accuracy was higher with AR features compared to PSD. In addition, the use of an SVM to classify the AR coefficients increased the classification rate by up to 16.3% compared to that reported in different work, where other classifiers were used. It was also observed that the combination of mental tasks for which highest classification was obtained varied from subject to subject; hence the mental tasks to be used should be carefully chosen to match each subject.

  13. Work function determination of promising electrode materials for thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Jacobson, D.; Storms, E.; Skaggs, B.; Kouts, T.; Jaskie, J.; Manda, M.

    1976-01-01

    The work function determinations of candidate materials for low temperature (1400 K) thermionics through vacuum emission tests are discussed. Two systems, a vacuum emission test vehicle and a thermionic emission microscope are used for emission measurements. Some nickel and cobalt based super alloys were preliminarily examined. High temperature physical properties and corrosion behavior of some super alloy candidates are presented. The corrosion behavior of sodium is of particular interest since topping cycles might use sodium heat transfer loops. A Marchuk tube was designed for plasma discharge studies with the carbide and possibly some super alloy samples. A series of metal carbides and other alloys were fabricated and tested in a special high temperature mass spectrometer. This information coupled with work function determinations was evaluated in an attempt to learn how electron bonding occurs in transition alloys.

  14. Study on the dynamic performance of a novel buck-boost matrix converter based on double-loop control strategy

    NASA Astrophysics Data System (ADS)

    Li, Qing; Zhang, Xiao-ping; Chen, Qi

    2011-12-01

    The dynamic performance of a novel Buck-Boost matrix converter (BBMC) based on double-loop control strategy is put forward in this paper. The fundamental principle of BBMC has been elaborated and the method of the double-loop control strategy has been built with Matlab, and then the dynamic performances of BBMC based on the double-loop control strategy are discussed. The results show that the output voltage and frequency can be almost constant with the BBMC and double-loop control strategy despite of the changeable input voltage and frequency. Moreover, a high-quality sine output wave with low harmonic distortion can be directly obtained without filtering. So it can be drawn that the BBMC based on the double-loop control strategy has perfectly dynamic performance and practical importance to the engineering.

  15. CMOS time-to-digital converter based on a pulse-mixing scheme.

    PubMed

    Chen, Chun-Chi; Hwang, Chorng-Sii; Liu, Keng-Chih; Chen, Guan-Hong

    2014-11-01

    This paper proposes a new pulse-mixing scheme utilizing both pulse-shrinking and pulse-stretching mechanisms to improve the performance of time-to-digital converters (TDCs). The temporal resolution of the conventional pulse-shrinking mechanism is determined by the size ratio between homogeneous and inhomogeneous elements. The proposed scheme which features double-stage operation derives its resolution according to the time difference between pulse-shrinking and pulse-stretching amounts. Thus, it can achieve greater immunity against temperature and ambient variations than that of the single-stage scheme. The circuit area also can be reduced by the proposed pulse-mixing scheme. In addition, this study proposes an improved cyclic delay line to eliminate the undesirable shift in the temporal resolution successfully. Therefore, the effective resolution can be controlled completely by the pulse-mixing unit to improve accuracy. The proposed TDC composed of only one cyclic delay line and one counter is fabricated in a TSMC CMOS 0.35-μm DPQM process. The chip core occupies an extremely small area of 0.02 mm(2), which is the best among the related works. The experimental result shows that an effective resolution of around 53 ps within ±13% variation over a 0-100 °C temperature range is achieved. The power consumption is 90 μW at a sample rate of 1000 samples/s. In addition to the reduced area, the proposed TDC circuit achieves its resolution with less thermal-sensitivity and better fluctuations caused by process variations. PMID:25430128

  16. CMOS time-to-digital converter based on a pulse-mixing scheme

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chi; Hwang, Chorng-Sii; Liu, Keng-Chih; Chen, Guan-Hong

    2014-11-01

    This paper proposes a new pulse-mixing scheme utilizing both pulse-shrinking and pulse-stretching mechanisms to improve the performance of time-to-digital converters (TDCs). The temporal resolution of the conventional pulse-shrinking mechanism is determined by the size ratio between homogeneous and inhomogeneous elements. The proposed scheme which features double-stage operation derives its resolution according to the time difference between pulse-shrinking and pulse-stretching amounts. Thus, it can achieve greater immunity against temperature and ambient variations than that of the single-stage scheme. The circuit area also can be reduced by the proposed pulse-mixing scheme. In addition, this study proposes an improved cyclic delay line to eliminate the undesirable shift in the temporal resolution successfully. Therefore, the effective resolution can be controlled completely by the pulse-mixing unit to improve accuracy. The proposed TDC composed of only one cyclic delay line and one counter is fabricated in a TSMC CMOS 0.35-μm DPQM process. The chip core occupies an extremely small area of 0.02 mm2, which is the best among the related works. The experimental result shows that an effective resolution of around 53 ps within ±13% variation over a 0-100 °C temperature range is achieved. The power consumption is 90 μW at a sample rate of 1000 samples/s. In addition to the reduced area, the proposed TDC circuit achieves its resolution with less thermal-sensitivity and better fluctuations caused by process variations.

  17. Easily processable multimodal spectral converters based on metal oxide/organic—inorganic hybrid nanocomposites

    NASA Astrophysics Data System (ADS)

    Julián-López, Beatriz; Gonell, Francisco; Lima, Patricia P.; Freitas, Vânia T.; André, Paulo S.; Carlos, Luis D.; Ferreira, Rute A. S.

    2015-10-01

    This manuscript reports the synthesis and characterization of the first organic-inorganic hybrid material exhibiting efficient multimodal spectral converting properties. The nanocomposite, made of Er3+, Yb3+ codoped zirconia nanoparticles (NPs) entrapped in a di-ureasil d-U(600) hybrid matrix, is prepared by an easy two-step sol-gel synthesis leading to homogeneous and transparent materials that can be very easily processed as monolith or film. Extensive structural characterization reveals that zirconia nanocrystals of 10-20 nm in size are efficiently dispersed into the hybrid matrix and that the local structure of the di-ureasil is not affected by the presence of the NPs. A significant enhancement in the refractive index of the di-ureasil matrix with the incorporation of the ZrO2 nanocrystals is observed. The optical study demonstrates that luminescent properties of both constituents are perfectly preserved in the final hybrid. Thus, the material displays a white-light photoluminescence from the di-ureasil component upon excitation at UV/visible radiation and also intense green and red emissions from the Er3+- and Yb3+-doped NPs after NIR excitation. The dynamics of the optical processes were also studied as a function of the lanthanide content and the thickness of the films. Our results indicate that these luminescent hybrids represent a low-cost, environmentally friendly, size-controlled, easily processed and chemically stable alternative material to be used in light harvesting devices such as luminescent solar concentrators, optical fibres and sensors. Furthermore, this synthetic approach can be extended to a wide variety of luminescent NPs entrapped in hybrid matrices, thus leading to multifunctional and versatile materials for efficient tuneable nonlinear optical nanodevices.

  18. Easily processable multimodal spectral converters based on metal oxide/organic-inorganic hybrid nanocomposites.

    PubMed

    Julián-López, Beatriz; Gonell, Francisco; Lima, Patricia P; Freitas, Vânia T; André, Paulo S; Carlos, Luis D; Ferreira, Rute A S

    2015-10-01

    This manuscript reports the synthesis and characterization of the first organic-inorganic hybrid material exhibiting efficient multimodal spectral converting properties. The nanocomposite, made of Er(3+), Yb(3+) codoped zirconia nanoparticles (NPs) entrapped in a di-ureasil d-U(600) hybrid matrix, is prepared by an easy two-step sol-gel synthesis leading to homogeneous and transparent materials that can be very easily processed as monolith or film. Extensive structural characterization reveals that zirconia nanocrystals of 10-20 nm in size are efficiently dispersed into the hybrid matrix and that the local structure of the di-ureasil is not affected by the presence of the NPs. A significant enhancement in the refractive index of the di-ureasil matrix with the incorporation of the ZrO2 nanocrystals is observed. The optical study demonstrates that luminescent properties of both constituents are perfectly preserved in the final hybrid. Thus, the material displays a white-light photoluminescence from the di-ureasil component upon excitation at UV/visible radiation and also intense green and red emissions from the Er(3+)- and Yb(3+)-doped NPs after NIR excitation. The dynamics of the optical processes were also studied as a function of the lanthanide content and the thickness of the films. Our results indicate that these luminescent hybrids represent a low-cost, environmentally friendly, size-controlled, easily processed and chemically stable alternative material to be used in light harvesting devices such as luminescent solar concentrators, optical fibres and sensors. Furthermore, this synthetic approach can be extended to a wide variety of luminescent NPs entrapped in hybrid matrices, thus leading to multifunctional and versatile materials for efficient tuneable nonlinear optical nanodevices. PMID:26374133

  19. Converting the organic fraction of solid waste from the city of Abu Dhabi to valuable products via dark fermentation – Economic and energy assessment

    SciTech Connect

    Bonk, Fabian Bastidas-Oyanedel, Juan-Rodrigo Schmidt, Jens Ejbye

    2015-06-15

    Graphical abstract: Display Omitted - Highlights: • The cost and energy demand for dark fermentation using OFMSW were established. • Dark fermentation using OFMSW can produce a carbon source for bioprocesses of about 330 USD/t{sub COD}. • A maximum purification cost of VFAs from dark fermentation using OFMSW was established to 15 USD/m{sup 3}. • Replacing fossil fuel based products by dark fermentation will probably lead to net energy savings. - Abstract: Landfilling the organic fraction of municipal solid waste (OFMSW) leads to greenhouse gas emissions and loss of valuable resources. Sustainable and cost efficient solutions need to be developed to solve this problem. This study evaluates the feasibility of using dark fermentation (DF) to convert the OFMSW to volatile fatty acids (VFAs), fertilizer and H{sub 2}. The VFAs in the DF effluent can be used directly as substrate for subsequent bioprocesses or purified from the effluent for industrial use. DF of the OFMSW in Abu Dhabi will be economically sustainable once VFA purification can be accomplished on large scale for less than 15 USD/m{sup 3}{sub effluent}. With a VFA minimum selling price of 330 USD/t{sub COD}, DF provides a competitive carbon source to sugar. Furthermore, DF is likely to use less energy than conventional processes that produce VFAs, fertilizer and H{sub 2}. This makes DF of OFMSW a promising waste treatment technology and biorefinery platform.

  20. Fully nonlinear time-domain simulation of a backward bent duct buoy floating wave energy converter using an acceleration potential method

    NASA Astrophysics Data System (ADS)

    Lee, Kyoung-Rok; Koo, Weoncheol; Kim, Moo-Hyun

    2013-12-01

    A floating Oscillating Water Column (OWC) wave energy converter, a Backward Bent Duct Buoy (BBDB), was simulated using a state-of-the-art, two-dimensional, fully-nonlinear Numerical Wave Tank (NWT) technique. The hydrodynamic performance of the floating OWC device was evaluated in the time domain. The acceleration potential method, with a full-updated kernel matrix calculation associated with a mode decomposition scheme, was implemented to obtain accurate estimates of the hydrodynamic force and displacement of a freely floating BBDB. The developed NWT was based on the potential theory and the boundary element method with constant panels on the boundaries. The mixed Eulerian-Lagrangian (MEL) approach was employed to capture the nonlinear free surfaces inside the chamber that interacted with a pneumatic pressure, induced by the time-varying airflow velocity at the air duct. A special viscous damping was applied to the chamber free surface to represent the viscous energy loss due to the BBDB's shape and motions. The viscous damping coefficient was properly selected using a comparison of the experimental data. The calculated surface elevation, inside and outside the chamber, with a tuned viscous damping correlated reasonably well with the experimental data for various incident wave conditions. The conservation of the total wave energy in the computational domain was confirmed over the entire range of wave frequencies.

  1. Virus-based piezoelectric energy generation

    NASA Astrophysics Data System (ADS)

    Lee, Byung Yang; Zhang, Jinxing; Zueger, Chris; Chung, Woo-Jae; Yoo, So Young; Wang, Eddie; Meyer, Joel; Ramesh, Ramamoorthy; Lee, Seung-Wuk

    2012-06-01

    Piezoelectric materials can convert mechanical energy into electrical energy, and piezoelectric devices made of a variety of inorganic materials and organic polymers have been demonstrated. However, synthesizing such materials often requires toxic starting compounds, harsh conditions and/or complex procedures. Previously, it was shown that hierarchically organized natural materials such as bones, collagen fibrils and peptide nanotubes can display piezoelectric properties. Here, we demonstrate that the piezoelectric and liquid-crystalline properties of M13 bacteriophage (phage) can be used to generate electrical energy. Using piezoresponse force microscopy, we characterize the structure-dependent piezoelectric properties of the phage at the molecular level. We then show that self-assembled thin films of phage can exhibit piezoelectric strengths of up to 7.8 pm V-1. We also demonstrate that it is possible to modulate the dipole strength of the phage, hence tuning the piezoelectric response, by genetically engineering the major coat proteins of the phage. Finally, we develop a phage-based piezoelectric generator that produces up to 6 nA of current and 400 mV of potential and use it to operate a liquid-crystal display. Because biotechnology techniques enable large-scale production of genetically modified phages, phage-based piezoelectric materials potentially offer a simple and environmentally friendly approach to piezoelectric energy generation.

  2. Thermoelectric generator operating with a cooling device for converting solar energy into electric energy, and system for the use thereof

    SciTech Connect

    Cannelli, P.

    1981-06-30

    A generator of electric energy by the transformation of thermal, solar energy, or of heat of any source, is described. The generator consists in one or more thermocouples combined with a cooling device, cooling down the weldings of the thermocouples on which heat is produced by the Peltier effect, also producing a very high thermal gradient. The cooling device exploits, for the functioning thereof, the phenomena which can be observed along the thermocouples. The system for the use of such a generator provides a particular disposition of the same in parabolic collectors, as to increase the sun ray concentration onto the weldings exposed to the heat and as to allow a decentralization in the electric energy supply by means of a plurality of generators consisting in only one thermocouple, said generators being interconnected.

  3. Converting Nonclassicality into Entanglement.

    PubMed

    Killoran, N; Steinhoff, F E S; Plenio, M B

    2016-02-26

    Quantum mechanics exhibits a wide range of nonclassical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well known that nonclassicality (e.g., squeezing, spin squeezing, coherence) can be converted into entanglement. In this work, we present a general framework, based on superposition, for structurally connecting and converting nonclassicality to entanglement. In addition to capturing the previously known results, this framework also allows us to uncover new entanglement convertibility theorems in two broad scenarios, one which is discrete and one which is continuous. In the discrete setting, the classical states can be any finite linearly independent set. For the continuous setting, the pertinent classical states are "symmetric coherent states," connected with symmetric representations of the group SU(K). These results generalize and link convertibility properties from the resource theory of coherence, spin coherent states, and optical coherent states, while also revealing important connections between local and nonlocal pictures of nonclassicality. PMID:26967398

  4. Measurement techniques for the characterization in the frequency domain of regulated energy-storage DC-to-DC converters. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Bahler, D. D.

    1978-01-01

    Procedures are presented for obtaining valid frequency-domain transfer functions of regulated reactor energy-storage dc-to-dc converters. These procedures are for measuring loop gain, closed loop gain, output impedance, and audio susceptibility. The applications of these measurements are discussed.

  5. Parametric performance analysis of steam-injected gas turbine with a thermionic-energy-converter-lined combustor

    NASA Technical Reports Server (NTRS)

    Choo, Y. K.; Burns, R. K.

    1982-01-01

    The performance of steam-injected gas turbines having combustors lined with thermionic energy converters (STIG/TEC systems) was analyzed and compared with that of two baseline systems; a steam-injected gas turbine (without a TEC-lined combustor) and a conventional combined gas turbine/steam turbine cycle. Common gas turbine parameters were assumed for all of the systems. Two configurations of the STIG/TEC system were investigated. In both cases, steam produced in an exhaust-heat-recovery boiler cools the TEC collectors. It is then injected into the gas combustion stream and expanded through the gas turbine. The STIG/TEC system combines the advantage of gas turbine steam injection with the conversion of high-temperature combustion heat by TEC's. The addition of TEC's to the baseline steam-injected gas turbine improves both its efficiency and specific power. Depending on system configuration and design parameters, the STIG/TEC system can also achieve higher efficiency and specific power than the baseline combined cycle.

  6. Determination of angiotensin I-converting enzyme activity in cell culture using fluorescence resonance energy transfer peptides.

    PubMed

    Sabatini, R A; Bersanetti, P A; Farias, S L; Juliano, L; Juliano, M A; Casarini, D E; Carmona, A K; Paiva, A C M; Pesquero, J B

    2007-04-15

    An assay using fluorescence resonance energy transfer peptides was developed to assess angiotensin I-converting enzyme (ACE) activity directly on the membrane of transfected Chinese hamster ovary cells (CHO) stably expressing the full-length somatic form of the enzyme. The advantage of the new method is the possibility of using selective substrates for the two active sites of the enzyme, namely Abz-FRK(Dnp)P-OH for somatic ACE, Abz-SDK(Dnp)P-OH for the N domain, and Abz-LFK(Dnp)-OH for the C domain. Hydrolysis of a peptide bond between the donor/acceptor pair (Abz/Dnp) generates detectable fluorescence, allowing quantitative measurement of the enzymatic activity. The kinetic parameter K(m) for the hydrolysis of the three substrates by ACE in this system was also determined and the values are comparable to those obtained using the purified enzyme in solution. The specificity of the activity was demonstrated by the complete inhibition of the hydrolysis by the ACE inhibitor lisinopril. Therefore, the results presented in this work show for the first time that determination of ACE activity directly on the surface of intact CHO cells is feasible and that the method is reliable and sensitive. In conclusion, we describe a methodology that may represent a new tool for the assessment of ACE activity which will open the possibility to study protein interactions in cells in culture. PMID:17320031

  7. A handy-motion driven, frequency up-converted hybrid vibration energy harvester using PZT bimorph and nonmagnetic ball

    NASA Astrophysics Data System (ADS)

    Halim, M. A.; Cho, H. O.; Park, J. Y.

    2014-11-01

    We have presented a frequency up-converted hybrid type (Piezoelectric and Electromagnetic) vibration energy harvester that can be used in powering portable and wearable smart devices by handy motion. A transverse impact mechanism has been employed for frequency up-conversion. Use of two transduction mechanisms increases the output power as well as power density. The proposed device consists of a non-magnetic spherical ball (freely movable at handy motion frequency) to impact periodically on the parabolic top of a piezoelectric (PZT) cantilevered mass by sliding over it, allowing it to vibrate at its higher resonant frequency and generates voltage by virtue of piezoelectric effect. A magnet attached to the cantilever vibrates along with it at the same frequency and a relative motion between the magnet and a coil placed below it, induces emf voltage across the coil terminals as well. A macro-scale prototype of the harvester has been fabricated and tested by handy motion. With an optimum magnet-coil overlap, a maximum 0.98mW and 0.64mW peak powers have been obtained from the piezoelectric and the electromagnetic transducers of the proposed device while shaken, respectively. It offers 84.4μWcm-3 peak power density.

  8. Study of a piezoelectric transformer-based DC/DC converter with a cooling system and current-doubler rectifier

    NASA Astrophysics Data System (ADS)

    Su, Yu-Hao; Liu, Yuan-Ping; Vasic, Dejan; Costa, Francois; Wu, Wen-Jong; Lee, Chuih-Kung

    2013-09-01

    The objective of this study was to increase the output current and power in a piezoelectric transformer (PT)-based DC/DC converter by using a cooling system. It is known that the output current of a PT is limited by temperature build-up because of losses, especially when driving at high vibration velocity. Although connecting different inductive circuits at the PT secondary terminal can increase the output current, the root cause of the temperature build-up problem has not yet been solved. This paper presents a study of a PT with cooling system in a DC/DC converter with a commonly used full-bridge rectifier and current-doubler rectifier. The advantages and disadvantages of the proposed technique were investigated. A theoretical-phenomenological model was developed to explain the relationship between the losses and the temperature rise. It will be shown that the vibration velocity as well as heat generation increases the losses. In our design, the maximum output current capacity can increase by 100% when the temperature of operation of the PT is kept below 55 ° C. The study comprises a theoretical part and experimental proof-of-concept demonstration of the proposed design method.

  9. Bolt axial stress measurement based on a mode-converted ultrasound method using an electromagnetic acoustic transducer.

    PubMed

    Ding, Xu; Wu, Xinjun; Wang, Yugang

    2014-03-01

    A method is proposed to measure the stress on a tightened bolt using an electromagnetic acoustic transducer (EMAT). A shear wave is generated by the EMAT, and a longitudinal wave is obtained from the reflection of the shear wave due to the mode conversion. The ray paths of the longitudinal and the shear wave are analyzed, and the relationship between the bolt axial stress and the ratio of time of flight between two mode waves is then formulated. Based on the above outcomes, an EMAT is developed to measure the bolt axial stress without loosening the bolt, which is required in the conventional EMAT test method. The experimental results from the measurement of the bolt tension show that the shear and the mode-converted longitudinal waves can be received successfully, and the ratio of the times of flight of the shear and the mode-converted longitudinal waves is linearly proportional to the bolt axial tension. The non-contact characteristic of EMAT eliminates the effect of the couplant and also makes the measurement more convenient than the measurement performed using the piezoelectric transducer. This method provides a promising way to measure the stress on tightened bolts. PMID:24289900

  10. Self-powered microthermionic converter

    SciTech Connect

    Marshall, Albert C.; King, Donald B.; Zavadil, Kevin R.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

    2004-08-10

    A self-powered microthermionic converter having an internal thermal power source integrated into the microthermionic converter. These converters can have high energy-conversion efficiencies over a range of operating temperatures. Microengineering techniques are used to manufacture the converter. The utilization of an internal thermal power source increases potential for mobility and incorporation into small devices. High energy efficiency is obtained by utilization of micron-scale interelectrode gap spacing. Alpha-particle emitting radioisotopes can be used for the internal thermal power source, such as curium and polonium isotopes.

  11. Hydrophobic polymer covered by a grating electrode for converting the mechanical energy of water droplets into electrical energy

    NASA Astrophysics Data System (ADS)

    Helseth, L. E.; Guo, X. D.

    2016-04-01

    Water contact electric harvesting has a great potential as a new energy technology for powering small-scale electronics, but a better understanding of the dynamics governing the conversion from mechanical to electrical energy on the polymer surfaces is needed. Important questions are how current correlates with droplet kinetic energy and what happens to the charge dynamics when a large number of droplets are incident on the polymer simultaneously. Here we address these questions by studying the current that is generated in an external electrical circuit when water droplets impinge on hydrophobic fluorinated ethylene propylene film containing a grating electrode on the back side. Droplets moving down an inclined polymer plane exhibit a characteristic periodic current time trace, and it is found that the peak current scales with sine of the inclination angle. For single droplets in free fall impinging onto the polymer, it is found that the initial peak current scales with the height of the free fall. The transition from individual droplets to a nearly continuous stream was investigated using the spectral density of the current signal. In both regimes, the high frequency content of the spectral density scales as f -2. For low frequencies, the low frequency content at low volume rates was noisy but nearly constant, whereas for high volume rates an increase with frequency is observed. It is demonstrated that the output signal from the system exposed to water droplets from a garden hose can be rectified and harvested by a 33 μF capacitor, where the stored energy increases at a rate of about 20 μJ in 100 s.

  12. Acoustic energy harvesting based on a planar acoustic metamaterial

    NASA Astrophysics Data System (ADS)

    Qi, Shuibao; Oudich, Mourad; Li, Yong; Assouar, Badreddine

    2016-06-01

    We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.

  13. Design of single-winding energy-storage reactors for dc-to-dc converters using air-gapped magnetic-core structures

    NASA Technical Reports Server (NTRS)

    Ohri, A. K.; Wilson, T. G.; Owen, H. A., Jr.

    1977-01-01

    A procedure is presented for designing air-gapped energy-storage reactors for nine different dc-to-dc converters resulting from combinations of three single-winding power stages for voltage stepup, current stepup and voltage stepup/current stepup and three controllers with control laws that impose constant-frequency, constant transistor on-time and constant transistor off-time operation. The analysis, based on the energy-transfer requirement of the reactor, leads to a simple relationship for the required minimum volume of the air gap. Determination of this minimum air gap volume then permits the selection of either an air gap or a cross-sectional core area. Having picked one parameter, the minimum value of the other immediately leads to selection of the physical magnetic structure. Other analytically derived equations are used to obtain values for the required turns, the inductance, and the maximum rms winding current. The design procedure is applicable to a wide range of magnetic material characteristics and physical configurations for the air-gapped magnetic structure.

  14. Development of a sub-nanosecond time-to-digital converter based on a field-programmable gate array

    NASA Astrophysics Data System (ADS)

    Sano, Y.; Tomoto, M.; Horii, Y.; Sasaki, O.; Uchida, T.; Ikeno, M.

    2016-03-01

    The present time-to-digital converter (TDC) chips for the monitored drift tube (MDT) chambers at the ATLAS experiment will be replaced with new ones for the High-Luminosity LHC, expected to begin operation in 2026. The design and the performance of a 24 channel TDC with a variable time binning of down to 0.28 nsec based on a Xilinx Kintex-7 field programmable gate array are reported. The time measurement is provided by a multisampling scheme with quad phase clocks synchronized with an external reference clock. The differential and integral nonlinearities have been measured to be less than half of the time binning. The temperature dependence on the performance is observed to be small. In conclusion the obtained performance of the time measurement is sufficiently high for the use with MDT chambers.

  15. FPGA-Based Self-Calibrating Time-to-Digital Converter for Time-of-Flight Experiments

    SciTech Connect

    Junnarkar, S.S.; O'Connor, P., Vaska, P., Fontaine, R.

    2009-08-12

    We describe the architecture of a FPGA-based self-calibrating Time to Digital Converter (TDC), specifically intended to measure the width of an input pulse. The configuration consists of two controllable ring oscillators with a very small difference in their frequencies, wherein this difference determines the achievable resolution. The calibration scheme relies on an accurate pulse-generator or external crystal-oscillator to provide a stable calibration pulse for the system. We implemented the TDC on an Altera Stratix II device where we measured a Least Significant Bit of 41 ps (an RMS resolution of 11.8 ps). We present details of the methods used to calibrate the TDC, the characterization process, and discuss the effects of variations in temperature and voltage.

  16. Converting Nonliquid Crystals into Liquid Crystals by N-Methylation in the Central Linker of Triazine-Based Dendrimers.

    PubMed

    Tsai, Meng-Jung; Hsieh, Jei-Way; Lai, Long-Li; Cheng, Kung-Lung; Liu, Shih-Hsien; Lee, Jey-Jau; Hsu, Hsiu-Fu

    2016-06-17

    Two triazine-based dendrimers were successfully prepared in 60-75% yields. These newly prepared dendrimers 2a and 2b containing the -NMe(CH2)2NMe- and the -NMe(CH2)4NMe- linkers between two G3 dendrons, respectively, exhibit columnar phases during the thermal process. However, the corresponding dendrimers 1a and 1b containing the -NH(CH2)2NH- and the -NH(CH2)4NH- linkers between two G3 dendrons, respectively, do not show any LC phases on thermal treatment. Computational investigations on molecular conformations reveal that N-methylation of the dendritic central linker leads dendrimers to possess more isomeric conformations and thus successfully converts non-LC dendrimers (1a and 1b) into LC dendrimers (2a and 2b). PMID:27203100

  17. Niobium nitride-based analog to digital converter using rapid single flux quantum logic operating at 9.5 K

    NASA Astrophysics Data System (ADS)

    Radparvar, Masoud; Rylov, Sergey

    1994-06-01

    An analog to digital converter (ADC) using the rapid single flux quantum (RSFQ) logic family implemented in niobium nitride (NbN) technology is described. The circuit was originally developed and demonstrated in niobium technology. An identical circuit was then laid out, fabricated and demonstrated in NbN technology. The chips were fabricated using an eight-layer NbN-based process with Josephson junction critical current density of 500 A/sq cm. In this paper, we report on the measurement results for a 6-bit flux quantizing ADC which exhibited proper operation and good dc bias margins. We will also demonstrate results from an ADC chip operating up to 9.5 K.

  18. Converting Equations and Graphs into Real Motion with Web-Based Interactive Activities.

    ERIC Educational Resources Information Center

    Chien, Cheng-Chih

    The physics learning problem that students usually regard equations and other symbols in physics as algebraic exercises rather than representations of real world phenomena is commonly known. This article discusses how the Web-based interactive instructional materials were used to help students connect the symbolic world and the real world. The…

  19. Power converter

    NASA Technical Reports Server (NTRS)

    Black, J. M. (Inventor)

    1981-01-01

    A dc-to-dc converter employs four transistor switches in a bridge to chop dc power from a source, and a voltage multiplying diode rectifying ladder network to rectify and filter the chopped dc power for delivery to a load. The bridge switches are cross coupled in order for diagonally opposite pairs to turn on and off together using RC networks for the cross coupling to achieve the mode of operation of a free running multivibrator, and the diode rectifying ladder is configured to operate in a push-pull mode driven from opposite sides of the multivibrator outputs of the ridge switches. The four transistor switches provide a square-wave output voltage which as a peak-to-peak amplitude that is twice the input dc voltage, and is thus useful as a dc-to-ac inverter.

  20. The discovery of novel tartrate-based TNF-[alpha] converting enzyme (TACE) inhibitors

    SciTech Connect

    Rosner, Kristin E.; Guo, Zhuyan; Orth, Peter; Shipps, Jr., Gerald W.; Belanger, David B.; Chan, Tin Yau; Curran, Patrick J.; Dai, Chaoyang; Deng, Yongqi; Girijavallabhan, Vinay M.; Hong, Liwu; Lavey, Brian J.; Lee, Joe F.; Li, Dansu; Liu, Zhidan; Popovici-Muller, Janeta; Ting, Pauline C.; Vaccaro, Henry; Wang, Li; Wang, Tong; Yu, W.; Zhou, G.; Niu, X.; Sun, J.; Kozlowski, J.A.; Lundell, D.J.; Madison, V.; McKittrick, B.; Piwinski, J.J.; Shih, N.Y.; Siddiqui, M. Arshad; Strickland, Corey O.

    2010-09-17

    A novel series of TNF-{alpha} convertase (TACE) inhibitors which are non-hydroxamate have been discovered. These compounds are bis-amides of L-tartaric acid (tartrate) and coordinate to the active site zinc in a tridentate manner. They are selective for TACE over other MMP's. We report the first X-ray crystal structure for a tartrate-based TACE inhibitor.

  1. Virus-based piezoelectric energy generator

    SciTech Connect

    2012-01-01

    Lawrence Berkeley National Laboratory scientists have developed a way to generate power using harmless viruses that convert mechanical energy into electricity. The milestone could lead to tiny devices that harvest electrical energy from the vibrations of everyday tasks. The first part of the video shows how Berkeley Lab scientists harness the piezoelectric properties of the virus to convert the force of a finger tap into electricity. The second part reveals the "viral-electric" generators in action, first by pressing only one of the generators, then by pressing two at the same time, which produces more current.

  2. A novel ultrafast all-optical NRZ to RZ format converter based on Sagnac interferometric structure

    NASA Astrophysics Data System (ADS)

    Chen, Zhixin

    2008-11-01

    A simple novel ultrafast scheme of all-optical nonreturn-to-zero(NRZ) to return-to-zero(RZ) is proposed based on Sagnac interferometric structure. The operations of this scheme at 40Gbit/s 27-1 PRBS sequences are simulated correctly with the output extinction ratio more than 19.1dB. Through built theoretical model and numerical analysis, the operating characteristics of the scheme are illustrated. Furthermore, the carrier recovery time of the SOA is no more a crucial parameter to restrict the operation speed of this scheme.

  3. Oil-fired cycling station converted to base-loaded, coal-burning operation

    SciTech Connect

    Hunt, J.; Steinbach, P.

    1982-04-01

    The Baltimore Gas and Electric Company has been able to modify its oil-fired Brandon Shores plant while under construction to a base-loaded plant able to burn either oil or coal. Utility planners had the foresight prior to the 1973 embargo to see advantages in a dual-fuel capability. Brandon Shores has experienced the same financing and fluctuating load problems as other projects, but it has evolved into a facility suited for the 1980s and 90s. The original plan included space to handle coal and wastes as well as specifying dual-fuel equipment throughout to minimize future modifications. During one construction delay, the utility initiated a preventative-maintenance program comparable to that of a nuclear plant that has been continued. Extensive environmental planning and interaction with the public have avoided other costly delays. (DCK)

  4. Increasing the noise immunity of optical-electronic systems based on video cameras with an optical converter

    NASA Astrophysics Data System (ADS)

    Boronenko, M. P.; Gulyaev, P. Yu; Seregin, A. E.; Poluhina, K. G.

    2015-11-01

    The luminophor coating of an electro- optical converter afterglow introduces an additional error to the measurement. The ratio that allows to calculate the intensity of spurious illumination at each subsequent frame have been determinate according to experimental data of luminescence kinetics. The proposed method increases the noise immunity of the electrooptical converter by eliminating luminophor afterglow.

  5. Convertible Stadium

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Air flotation technology used in NASA's Apollo program has found an interesting application in Hawaii's Aloha Stadium near Honolulu. The stadium's configuration can be changed, by moving entire 7,000-seat sections on a cushion of air, for best accommodation of spectators and participants at different types of events. In most stadiums, only a few hundred seats can be moved, by rolling sections on wheels or rails. At Aloha Stadium, 28,000 of the 50,000 seats can be repositioned for better spectator viewing and, additionally, for improved playing conditions. For example, a stadium designed primarily for football may compromise the baseball diamond by providing only a shallow outfield. Aloha's convertibility allows a full-size baseball field as well as optimum configurations for many other types of sports and special events. The photos show examples. The stadium owes its versatility to air flotation technology developed by General Motors. Its first large-scale application was movement of huge segments of the mammoth Saturn V moonbooster during assembly operations at Marshall Space Flight Center.

  6. Thermionic converter

    DOEpatents

    Rasor, Ned S.; Britt, Edward J.

    1976-01-01

    A gas-filled thermionic converter is provided with a collector and an emitter having a main emitter region and an auxiliary emitter region in electrical contact with the main emitter region. The main emitter region is so positioned with respect to the collector that a main gap is formed therebetween and the auxiliary emitter region is so positioned with respect to the collector that an auxiliary gap is formed therebetween partially separated from the main gap with access allowed between the gaps to allow ionizable gas in each gap to migrate therebetween. With heat applied to the emitter the work function of the auxiliary emitter region is sufficiently greater than the work function of the collector so that an ignited discharge occurs in the auxiliary gap and the work function of the main emitter region is so related to the work function of the collector that an unignited discharge occurs in the main gap sustained by the ions generated in the auxiliary gap. A current flows through a load coupled across the emitter and collector due to the unignited discharge in the main gap.

  7. A multi-path gated ring oscillator based time-to-digital converter in 65 nm CMOS technology

    NASA Astrophysics Data System (ADS)

    Chen, Jiang; Yumei, Huang; Zhiliang, Hong

    2013-03-01

    A gated ring oscillator (GRO) based time-to-digital converter (TDC) is presented. To enhance the resolution of the TDC, a multi-path structure for the GRO is used to achieve a higher oscillation frequency and an input stage is also presented to equivalently amplify the input time difference with a gain of 2. The GRO based TDC circuit is fabricated in TSMC 65 nm CMOS technology and the core area is about 0.02 mm2. According to the measurement results, the effective resolution of this circuit is better than 4.22 ps under a 50 MHz clock frequency. With a 1 ns input range, the maximum clock frequency of this circuit is larger than 200 MHz. Under a 1 V power supply, with a 200-800 ps input time difference, the measured power consumption is 1.24 to 1.72 mW at 50 MHz clock frequency and 1.73 to 2.20 mW at 200 MHz clock frequency.

  8. Fabrication and characterization of silicon based thermal neutron detector with hot wire chemical vapor deposited boron carbide converter

    NASA Astrophysics Data System (ADS)

    Chaudhari, Pradip; Singh, Arvind; Topkar, Anita; Dusane, Rajiv

    2015-04-01

    In order to utilize the well established silicon detector technology for neutron detection application, a silicon based thermal neutron detector was fabricated by integrating a thin boron carbide layer as a neutron converter with a silicon PIN detector. Hot wire chemical vapor deposition (HWCVD), which is a low cost, low temperature process for deposition of thin films with precise thickness was explored as a technique for direct deposition of a boron carbide layer over the metalized front surface of the detector chip. The presence of B-C bonding and 10B isotope in the boron carbide film were confirmed by Fourier transform infrared spectroscopy and secondary ion mass spectrometry respectively. The deposition of HWCVD boron carbide layer being a low temperature process was observed not to cause degradation of the PIN detector. The response of the detector with 0.2 μm and 0.5 μm thick boron carbide layer was examined in a nuclear reactor. The pulse height spectrum shows evidence of thermal neutron response with signature of (n, α) reaction. The results presented in this article indicate that HWCVD boron carbide deposition technique would be suitable for low cost industrial fabrication of PIN based single element or 1D/2D position sensitive thermal neutron detectors.

  9. Development of electron reflection suppression materials for improved thermionic energy converter performance using thin film deposition techniques

    SciTech Connect

    Islam, Mohammad; Inal, Osman T.; Luke, James R.

    2006-10-15

    Nonideal electrode surfaces cause significant degree of electron reflection from collector during thermionic converter operation. The effect of the collector surface structure on the converter performance was assessed through the development of several electron reflection suppression materials using various thin film deposition techniques. The double-diode probe method was used to compare the J-V characteristics of converters with polished and modified collector surfaces for emitter temperature and cesium vapor pressure in the ranges of 900-2000 K and 0.02-1.5 torr, respectively. The coadsorption of cesium and oxygen with respective partial vapor pressures of {approx}1.27 torr and a few microtorrs reduced the emitter work function to a minimum value of 0.99 eV. It was found that the collector surfaces with matte black appearance such as platinum black, voided nickel from radio-frequency plasma sputtering, and etched electroless Ni-P with craterlike pore morphology exhibited much better performance compared with polished collector surface. For these thin films, the increase in the maximum output voltage was up to 2.0 eV. For optimum performance with minimum work function and maximum saturation emission current density, the emitter temperature was in the range of 1100-1500 K, depending on the collector surface structure. The use of these materials in cylindrical converter design and/or in combination with hybrid mode triode configuration holds great potential in low and medium scale power generators for commercial use.

  10. Converting oil shale to liquid fuels: energy inputs and greenhouse gas emissions of the Shell in situ conversion process.

    PubMed

    Brandt, Adam R

    2008-10-01

    Oil shale is a sedimentary rock that contains kerogen, a fossil organic material. Kerogen can be heated to produce oil and gas (retorted). This has traditionally been a CO2-intensive process. In this paper, the Shell in situ conversion process (ICP), which is a novel method of retorting oil shale in place, is analyzed. The ICP utilizes electricity to heat the underground shale over a period of 2 years. Hydrocarbons are produced using conventional oil production techniques, leaving shale oil coke within the formation. The energy inputs and outputs from the ICP, as applied to oil shales of the Green River formation, are modeled. Using these energy inputs, the greenhouse gas (GHG) emissions from the ICP are calculated and are compared to emissions from conventional petroleum. Energy outputs (as refined liquid fuel) are 1.2-1.6 times greater than the total primary energy inputs to the process. In the absence of capturing CO2 generated from electricity produced to fuel the process, well-to-pump GHG emissions are in the range of 30.6-37.1 grams of carbon equivalent per megajoule of liquid fuel produced. These full-fuel-cycle emissions are 21%-47% larger than those from conventionally produced petroleum-based fuels. PMID:18939591

  11. ASIC and FPGA based DPWM architectures for single-phase and single-output DC-DC converter: a review

    NASA Astrophysics Data System (ADS)

    Chander, Subhash; Agarwal, Pramod; Gupta, Indra

    2013-12-01

    Pulse width modulation (PWM) has been widely used in power converter control. This paper presents a review of architectures of the Digital Pulse Width Modulators (DPWM) targeting digital control of switching DC-DC converters. An attempt is made to review the reported architectures with emphasis on the ASIC and FPGA implementations in single phase and single-output DC-DC converters. Recent architectures using FPGA's advanced resources for achieving the resolution higher than classical methods have also been discussed. The merits and demerits of different architectures, and their relative comparative performance, are also presented. The Authors intention is to uncover the groundwork and the related references through this review for the benefit of readers and researchers targeting different DPWM architectures for the DC-DC converters.

  12. Convertible resistive switching characteristics between memory switching and threshold switching in a single ferritin-based memristor.

    PubMed

    Zhang, Chaochao; Shang, Jie; Xue, Wuhong; Tan, Hongwei; Pan, Liang; Yang, Xi; Guo, Shanshan; Hao, Jian; Liu, Gang; Li, Run-Wei

    2016-04-01

    A bio-memristor fabricated with ferritin exhibits novel resistive switching characteristics wherein memory switching and threshold switching are made steadily coexistent and inter-convertible through controlling the magnitude of compliance current presets. PMID:26967024

  13. Fully Integrated Ultra-Low Voltage Step-up Converter with Voltage Doubling LC-Tank for Energy Harvesting Applications

    NASA Astrophysics Data System (ADS)

    Jayaweera, H. M. P. C.; Pathirana, W. P. M. R.; Muhtaroğlu, Ali

    2015-12-01

    This paper reports the design, fabrication, and validation of a novel integrated interface circuit for ultra-low voltage step up converter in 0.18 μm CMOS technology. The circuit does not use off-chip components. Fully integrated centre-tap differential inductors are introduced in the proposed LC oscillator design to achieve 38% area reduction compared to the use of four separate inductors. The efficiency of the system is hence enhanced through the elimination of clock buffer circuits traditionally utilized to drive the step-up converter. The experimental results prove that the system can self-start, and step 0.25 V up to 1.7 V to supply a 46 μW load with 15.5% efficiency. The minimum validated input voltage is 0.15 V, which is boosted up to 1.2 V under open circuit conditions.

  14. Multistage spectral polarimeter based on integrated acousto-optical Ti:LiNbO3 TE-TM converters for WDM system monitoring

    NASA Astrophysics Data System (ADS)

    Noe, Reinhold; Maucher, A.; Ricken, Raimund

    1999-04-01

    A 4-stage spectral polarimeter based on Ti:LiNbO3 acousto- optical TE-TM converters has been realized. It has about 20 dB stopband suppression and can measure polarimetric spectra as well as the time evolution of the state of polarization. A simple optical spectrum analyzer is also proposed.

  15. Successive approximation-like 4-bit full-optical analog-to-digital converter based on Kerr-like nonlinear photonic crystal ring resonators

    NASA Astrophysics Data System (ADS)

    Tavousi, Alireza; Mansouri-Birjandi, Mohammad Ali; Saffari, Mehdi

    2016-09-01

    Implementing of photonic sampling and quantizing analog-to-digital converters (ADCs) enable us to extract a single binary word from optical signals without need for extra electronic assisting parts. This would enormously increase the sampling and quantizing time as well as decreasing the consumed power. To this end, based on the concept of successive approximation method, a 4-bit full-optical ADC that operates using the intensity-dependent Kerr-like nonlinearity in a two dimensional photonic crystal (2DPhC) platform is proposed. The Silicon (Si) nanocrystal is chosen because of the suitable nonlinear material characteristic. An optical limiter is used for the clamping and quantization of each successive levels that represent the ADC bits. In the proposal, an energy efficient optical ADC circuit is implemented by controlling the system parameters such as ring-to-waveguide coupling coefficients, the ring's nonlinear refractive index, and the ring's length. The performance of the ADC structure is verified by the simulation using finite difference time domain (FDTD) method.

  16. Simulation-based high-level synthesis of Nyquist-rate data converters using MATLAB/SIMULINK

    NASA Astrophysics Data System (ADS)

    Ruiz-Amaya, Jesus; de la Rosa, Jose M.; Delgado-Restituto, Manuel; Rodriguez-Vazquez, Angel

    2005-06-01

    This paper presents a toolbox for the simulation, optimization and high-level synthesis of Nyquist-rate Analog-to-Digital (A/D) and Digital-to-Analog (D/A) Converters in MATLAB. The embedded simulator uses SIMULINK C-coded S-functions to model all required subcircuits including their main error mechanisms. This approach allows to drastically speed up the simulation CPU-time up to 2 orders of magnitude as compared with previous approaches - based on the use of SIMULINK elementary blocks. Moreover, S-functions are more suitable for implementing a more detailed description of the circuit. For all subcircuits, the accuracy of the behavioral models has been verified by electrical simulation using HSPICE. For synthesis purposes, the simulator is used for performance evaluation and combined with an hybrid optimizer for design parameter selection. The optimizer combines adaptive statistical optimization algorithm inspired in simulated annealing with a design-oriented formulation of the cost function. It has been integrated in the MATLAB/SIMULINK platform by using the MATLAB engine library, so that the optimization core runs in background while MATLAB acts as a computation engine. The implementation on the MATLAB platform brings numerous advantages in terms of signal processing, high flexibility for tool expansion and simulation with other electronic subsystems. Additionally, the presented toolbox comprises a friendly graphical user interface to allow the designer to browse through all steps of the simulation, synthesis and post-processing of results. In order to illustrate the capabilities of the toolbox, a 0.13μm CMOS 12-bit@80MS/s analog front-end for broadband power line communications, made up of a pipeline ADC and a current steering DAC, is synthesized and high-level sized. Different experiments show the effectiveness of the proposed methodology.

  17. Nano-polarization-converter based on magnetic plasmon resonance excitation in an L-shaped slot antenna.

    PubMed

    Yang, Jing; Zhang, Jiasen

    2013-04-01

    We propose a nano-polarization-converter made of a resonant L-shaped slot antenna in a gold film and study its optical properties using the finite-difference time-domain method. Phase retardation between the fast and slow axes of the nano-polarization-converter originates from the simultaneous excitation of both single-surface first-order magnetic plasmon resonance mode and second-order magnetic plasmon resonance mode at the working wavelength. By adjusting the size of the slot antenna, which is still much smaller than the wavelength, the working wavelength can be tuned within a large wavelength range. PMID:23571885

  18. Recent Additions in the Modeling Capabilities of an Open-Source Wave Energy Converter Design Tool: Preprint

    SciTech Connect

    Tom, N.; Lawson, M.; Yu, Y. H.

    2015-04-20

    WEC-Sim is a midfidelity numerical tool for modeling wave energy conversion devices. The code uses the MATLAB SimMechanics package to solve multibody dynamics and models wave interactions using hydrodynamic coefficients derived from frequency-domain boundary-element methods. This paper presents the new modeling features introduced in the latest release of WEC-Sim. The first feature discussed conversion of the fluid memory kernel to a state-space form. This enhancement offers a substantial computational benefit after the hydrodynamic body-to-body coefficients are introduced and the number of interactions increases exponentially with each additional body. Additional features include the ability to calculate the wave-excitation forces based on the instantaneous incident wave angle, allowing the device to weathervane, as well as import a user-defined wave elevation time series. A review of the hydrodynamic theory for each feature is provided and the successful implementation is verified using test cases.

  19. A universal electromagnetic energy conversion adapter based on a metamaterial absorber.

    PubMed

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D; Simons, Rainee N; Chen, Yunpeng; Xiao, John Q

    2014-01-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor. PMID:25200005

  20. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-09-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor.

  1. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    PubMed Central

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-01-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor. PMID:25200005

  2. Converting Spreadsheet Files into Data Base Files Using AppleWorks V2.0 and the Apple IIGS Computer.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.

    This guide was developed as a "how to" training device for converting spreadsheet files into database files using AppleWorks version 2.0 on the Apple IIGS computer with two disk drives. Step-by-step instructions are provided for loading spreadsheet files, transferring spreadsheet files to the monitor, printing spreadsheet files, and using the data…

  3. Mode converter based on the long-period fiber gratings written in the two-mode fiber.

    PubMed

    Zhao, Yunhe; Liu, Yunqi; Zhang, Liang; Zhang, Chenyi; Wen, Jianxiang; Wang, Tingyun

    2016-03-21

    We demonstrate the fabrication of long-period fiber gratings (LPFGs) written in the two-mode fiber (TMF) by CO2 laser. Both uniform and tilted LPFGs were fabricated to provide the light coupling between LP01 mode and LP11 mode with a coupling efficiency of more than 99%. The writing efficiency and the bandwidth of the LPFG mode converter can be adjusted by changing the tilt angle of the tilted TMF-LPFGs. The torsion sensitivity of conventional and tilted LPFG mode converters were measured to be 0.37 nm/(rad/m) and 0.50 nm/(rad/m), respectively. Two orthogonal vector modes (the HEeven 21and HEodd 21 modes) and corresponding orbital angular momentum state were successfully obtained at the resonance wavelength. The proposed LPFG mode converter could be used as not only a high efficiency wavelength tunable mode converter in the mode division multiplexing system but also a high sensitive torsion sensor in the field of optical sensing. PMID:27136812

  4. The thermionic energy converter as a topping cycle for more efficient heat engines—new triode designs with a longitudinal magnetic field

    NASA Astrophysics Data System (ADS)

    Moyzhes, B. Y.; Geballe, T. H.

    2005-03-01

    A new concept for converting heat energy to electrical energy using thermionic energy converters (TECs) is proposed. It has potential for increasing the Carnot efficiency to an unprecedented 80% when the TEC is combined as a topping cycle with a conventional external combustion engine. The optimal electrical power density, 5-20 W cm-2, is satisfactory for many applications including stationary power generators and propulsion drives for vehicles. But unfortunately the substantial losses, ~50% of the output power, that have been needed to compensate the space charge have prevented the TEC from realizing its thermodynamic potential. We present two ways of overcoming this limitation. Both utilize a triode configuration (rather than a simple diode) with a longitudinal magnetic field. In the first method the magnetic field together with the grid separate the relatively few hot electrons required for volume generation of Cs ions used for the space charge compensation from the majority of the thermal electrons which constitute the current to the collector. In the second method the Cs ions are generated on the surface of the grid wires and injected into the space between the electrodes. Grid wires with high work functions are required for this.

  5. Micromotor-based energy generation.

    PubMed

    Singh, Virendra V; Soto, Fernando; Kaufmann, Kevin; Wang, Joseph

    2015-06-01

    A micromotor-based strategy for energy generation, utilizing the conversion of liquid-phase hydrogen to usable hydrogen gas (H2), is described. The new motion-based H2-generation concept relies on the movement of Pt-black/Ti Janus microparticle motors in a solution of sodium borohydride (NaBH4) fuel. This is the first report of using NaBH4 for powering micromotors. The autonomous motion of these catalytic micromotors, as well as their bubble generation, leads to enhanced mixing and transport of NaBH4 towards the Pt-black catalytic surface (compared to static microparticles or films), and hence to a substantially faster rate of H2 production. The practical utility of these micromotors is illustrated by powering a hydrogen-oxygen fuel cell car by an on-board motion-based hydrogen and oxygen generation. The new micromotor approach paves the way for the development of efficient on-site energy generation for powering external devices or meeting growing demands on the energy grid. PMID:25906739

  6. Broadband photonic single sideband frequency up-converter based on the cross polarization modulation effect in a semiconductor optical amplifier for radio-over-fiber systems.

    PubMed

    Lee, Seung-Hun; Kim, Hyoung-Jun; Song, Jong-In

    2014-01-13

    A broadband photonic single sideband (SSB) frequency up-converter based on the cross polarization modulation (XPolM) effect in a semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. An optical radio frequency (RF) signal in the form of an optical single sideband (OSSB) is generated by the photonic SSB frequency up-converter to solve the power fading problem caused by fiber chromatic dispersion. The generated OSSB RF signal has almost identical optical carrier power and optical sideband power. This SSB frequency up-conversion scheme shows an almost flat electrical RF power response as a function of the RF frequency in a range from 31 GHz to 75 GHz after 40 km single mode fiber (SMF) transmission. The photonic SSB frequency up-conversion technique shows negligible phase noise degradation. The phase noise of the up-converted RF signal at 49 GHz for an offset of 10 kHz is -93.17 dBc/Hz. Linearity analysis shows that the photonic SSB frequency up-converter has a spurious free dynamic range (SFDR) value of 79.51 dB · Hz(2/3). PMID:24514980

  7. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics.

    PubMed

    Pandey, Ajay K

    2015-01-01

    Free charge generation in donor-acceptor (D-A) based organic photovoltaic diodes (OPV) progresses through formation of charge-transfer (CT) and charge-separated (CS) states and excitation decay to the triplet level is considered as a terminal loss. On the other hand a direct excitation decay to the triplet state is beneficial for multiexciton harvesting in singlet fission photovoltaics (SF-PV) and the formation of CT-state is considered as a limiting factor for multiple triplet harvesting. These two extremes when present in a D-A system are expected to provide important insights into the mechanism of free charge generation and spin-character of bimolecular recombination in OPVs. Herein, we present the complete cycle of events linked to spin conversion in the model OPV system of rubrene/C60. By tracking the spectral evolution of photocurrent generation at short-circuit and close to open-circuit conditions we are able to capture spectral changes to photocurrent that reveal the triplet character of CT-state. Furthermore, we unveil an energy up-conversion effect that sets in as a consequence of triplet population build-up where triplet-triplet annihilation (TTA) process effectively regenerates the singlet excitation. This detailed balance is shown to enable a rare event of photon emission just above the open-circuit voltage (V(OC)) in OPVs. PMID:25585937

  8. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics

    NASA Astrophysics Data System (ADS)

    Pandey, Ajay K.

    2015-01-01

    Free charge generation in donor-acceptor (D-A) based organic photovoltaic diodes (OPV) progresses through formation of charge-transfer (CT) and charge-separated (CS) states and excitation decay to the triplet level is considered as a terminal loss. On the other hand a direct excitation decay to the triplet state is beneficial for multiexciton harvesting in singlet fission photovoltaics (SF-PV) and the formation of CT-state is considered as a limiting factor for multiple triplet harvesting. These two extremes when present in a D-A system are expected to provide important insights into the mechanism of free charge generation and spin-character of bimolecular recombination in OPVs. Herein, we present the complete cycle of events linked to spin conversion in the model OPV system of rubrene/C60. By tracking the spectral evolution of photocurrent generation at short-circuit and close to open-circuit conditions we are able to capture spectral changes to photocurrent that reveal the triplet character of CT-state. Furthermore, we unveil an energy up-conversion effect that sets in as a consequence of triplet population build-up where triplet-triplet annihilation (TTA) process effectively regenerates the singlet excitation. This detailed balance is shown to enable a rare event of photon emission just above the open-circuit voltage (VOC) in OPVs.

  9. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics

    PubMed Central

    Pandey, Ajay K.

    2015-01-01

    Free charge generation in donor-acceptor (D-A) based organic photovoltaic diodes (OPV) progresses through formation of charge-transfer (CT) and charge-separated (CS) states and excitation decay to the triplet level is considered as a terminal loss. On the other hand a direct excitation decay to the triplet state is beneficial for multiexciton harvesting in singlet fission photovoltaics (SF-PV) and the formation of CT-state is considered as a limiting factor for multiple triplet harvesting. These two extremes when present in a D-A system are expected to provide important insights into the mechanism of free charge generation and spin-character of bimolecular recombination in OPVs. Herein, we present the complete cycle of events linked to spin conversion in the model OPV system of rubrene/C60. By tracking the spectral evolution of photocurrent generation at short-circuit and close to open-circuit conditions we are able to capture spectral changes to photocurrent that reveal the triplet character of CT-state. Furthermore, we unveil an energy up-conversion effect that sets in as a consequence of triplet population build-up where triplet-triplet annihilation (TTA) process effectively regenerates the singlet excitation. This detailed balance is shown to enable a rare event of photon emission just above the open-circuit voltage (VOC) in OPVs. PMID:25585937

  10. Pulse doubling in zigzag-connected autotransformer-based 12-pulse ac-dc converter for power quality improvement

    NASA Astrophysics Data System (ADS)

    Abdollahi, Rohollah

    2012-12-01

    This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMDs) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse acdc converters each of them consisting of three-phase diode bridge rectifiers. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6-pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.

  11. Hybrid Electric Vehicle Power Management Solutions Based on Isolated and Non-Isolated Configurations of MMCCC Converter

    SciTech Connect

    Khan, Faisal H; Tolbert, Leon M; Webb, William E

    2009-01-01

    This paper presents the various configurations of a multilevel modular capacitor-clamped converter (MMCCC), and it reveals many useful and new formations of the original MMCCC for transferring power in either an isolated or nonisolated manner. The various features of the original MMCCC circuit are best suited for a multibus system in future plug-in hybrid or fuel-cell-powered vehicles' drive train. The original MMCCC is capable of bidirectional power transfer using multilevel modular structure with capacitor-clamped topology. It has a nonisolated structure, and it offers very high efficiency even at partial loads. This circuit was modified to integrate single or multiple high-frequency transformers by using the intermediate voltage nodes of the converter. On the other hand, a special formation of the MMCCC can exhibit dc outputs offering limited isolation without using any isolation transformer. This modified version can produce a high conversion ratio from a limited number of components and has several useful applications in providing power to multiple low-voltage loads in a hybrid or electric automobile. This paper will investigate the origin of generating ac outputs from the MMCCC and shows how the transformer-free version can be modified to create limited isolation from the circuit. In addition, this paper will compare various modified forms of the MMCCC topology with existing dc-dc converter circuits from compactness and component utilization perspectives.

  12. Electrochemical treatment of tannery effluent using a battery integrated DC-DC converter and solar PV power supply--an approach towards environment and energy management.

    PubMed

    Iyappan, K; Basha, C Ahmed; Saravanathamizhan, R; Vedaraman, N; Tahiyah Nou Shene, C A; Begum, S Nathira

    2014-01-01

    Electrochemical oxidation of tannery effluent was carried out in batch, batch recirculation and continuous reactor configurations under different conditions using a battery-integrated DC-DC converter and solar PV power supply. The effect of current density, electrolysis time and fluid flow rate on chemical oxygen demand (COD) removal and energy consumption has been evaluated. The results of batch reactor show that a COD reduction of 80.85% to 96.67% could be obtained. The results showed that after 7 h of operation at a current density of 2.5 A dm(-2) and flow rate of 100 L h(-1) in batch recirculation reactor, the removal of COD is 82.14% and the specific energy consumption was found to be 5.871 kWh (kg COD)(-1) for tannery effluent. In addition, the performance of single pass flow reactors (single and multiple reactors) system of various configurations are analyzed. PMID:24844896

  13. Space Based Dark Energy Surveys

    NASA Astrophysics Data System (ADS)

    Dore, Olivier

    2016-03-01

    Dark energy, the name given to the cause of the accelerating expansion of the Universe, is one of the most tantalizing mystery in modern physics. Current cosmological models hold that dark energy is currently the dominant component of the Universe, but the exact nature of DE remains poorly understood. There are ambitious ground-based surveys underway that seek to understand DE and NASA is participating in the development of significantly more ambitious space-based surveys planned for the next decade. NASA has provided mission enabling technology to the European Space Agency's (ESA) Euclid mission in exchange for US scientists to participate in the Euclid mission. NASA is also developing the Wide Field Infrared Survey Telescope-Astrophysics Focused Telescope Asset (WFIRST) mission for possible launch in 2024. WFIRST was the highest ranked space mission in the Astro2010 Decadal Survey and the current design uses a 2.4m space telescope to go beyond what was then envisioned. Understanding DE is one of the primary science goals of WFIRST-AFTA. This talk will review the state of DE, the relevant activities of the Cosmic Structure Interest Group (CoSSIG) of the PhyPAG, and detail the status and complementarity between Euclid, WFIRST and ot ambitious ground-based efforts.

  14. Fluid bed gasification – Plasma converter process generating energy from solid waste: Experimental assessment of sulphur species

    SciTech Connect

    Morrin, Shane; Lettieri, Paola; Chapman, Chris; Taylor, Richard

    2014-01-15

    Highlights: • We investigate gaseous sulphur species whilst gasifying sulphur-enriched wood pellets. • Experiments performed using a two stage fluid bed gasifier – plasma converter process. • Notable SO{sub 2} and relatively low COS levels were identified. • Oxygen-rich regions of the bed are believed to facilitate SO{sub 2}, with a delayed release. • Gas phase reducing regions above the bed would facilitate more prompt COS generation. - Abstract: Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed. Notable SO{sub 2} and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO{sub 2}’s generation. The response of COS to sulphur in the feed was quite prompt, whereas SO{sub 2} was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO{sub 2} generation. The more reducing gas phase regions above the bed would have facilitated COS – hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling.

  15. A 1 MW, 100 kV, less than 100 kg space based dc-dc power converter

    NASA Technical Reports Server (NTRS)

    Cooper, J. R.; White, C. W.

    1991-01-01

    A 1 MW dc-dc power converter has been designed which has an input voltage of 5 kV +/-3 percent, an output voltage of 100 kV +/- 0.25 percent, and a run time of 1000 s at full power. The estimated system mass is 83.8 kg, giving a power density of 11.9 kW/kg. The system exceeded the weight goal of 10 kW/kg through the use of innovative components and system concepts. The system volume is approximately 0.1 cu m, and the overall system efficiency is estimated to be 87 percent. Some of the unique system features include a 50-kHz H-bridge inverter using MOS-controlled thyristors as the switching devices, a resonance transformer to step up the voltage, open-cycle cryogenic hydrogen gas cooling, and a nonrigid, inflatable housing which provides on-demand pressurization of the power converter local environment. This system scales very well to higher output powers. The weight of the 10-MW system with the same input and output voltage requirements and overall system configuration is estimated to be 575.3 kg. This gives a power density of 17.4 kW/kg, significantly higher than the 11.9 kW/kg estimated at 1 MW.

  16. From Waste to Watts: The fermentation of animal waste occuring in a digester producing methane gasses as a side product and converted to energy.

    NASA Astrophysics Data System (ADS)

    Weiss, S.

    2015-12-01

    The waste product from animals is readily available all over the world, including third world countries. Using animal waste to produce green energy would allow low cost energy sources and give independence from fossil fuels. But which animal produces the most methane and how hard is it to harvest? Before starting this experiment I knew that some cow farms in the northern part of the Central California basin were using some of the methane from the waste to power their machinery as a safer, cheaper and greener source through the harnessed methane gas in a digester. The fermentation process would occur in the digester producing methane gasses as a side product. Methane that is collected can later be burned for energy. I have done a lot of research on this experiment and found that many different farm and ranch animals produce methane, but it was unclear which produced the most. I decided to focus my study on the waste from cows, horses, pig and dogs to try to find the most efficient and strongest source of methane from animal waste. I produced an affordable methane digester from plastic containers with a valve to attach a hose. By putting in the waste product and letting it ferment with water, I was able to produce and capture methane, then measure the amount with a Gaslab meter. By showing that it is possible to create energy with this simple digester, it could reduce pollution and make green energy easily available to communities all over the world. Eventually this could result into our sewer systems converting waste to energy, producing an energy source right in your home.

  17. Investigation of a tubular dual-stator flux-switching permanent-magnet linear generator for free-piston energy converter

    NASA Astrophysics Data System (ADS)

    Sui, Yi; Zheng, Ping; Tong, Chengde; Yu, Bin; Zhu, Shaohong; Zhu, Jianguo

    2015-05-01

    This paper describes a tubular dual-stator flux-switching permanent-magnet (PM) linear generator for free-piston energy converter. The operating principle, topology, and design considerations of the machine are investigated. Combining the motion characteristic of free-piston Stirling engine, a tubular dual-stator PM linear generator is designed by finite element method. Some major structural parameters, such as the outer and inner radii of the mover, PM thickness, mover tooth width, tooth width of the outer and inner stators, etc., are optimized to improve the machine performances like thrust capability and power density. In comparison with conventional single-stator PM machines like moving-magnet linear machine and flux-switching linear machine, the proposed dual-stator flux-switching PM machine shows advantages in higher mass power density, higher volume power density, and lighter mover.

  18. Converting the organic fraction of solid waste from the city of Abu Dhabi to valuable products via dark fermentation--Economic and energy assessment.

    PubMed

    Bonk, Fabian; Bastidas-Oyanedel, Juan-Rodrigo; Schmidt, Jens Ejbye

    2015-06-01

    Landfilling the organic fraction of municipal solid waste (OFMSW) leads to greenhouse gas emissions and loss of valuable resources. Sustainable and cost efficient solutions need to be developed to solve this problem. This study evaluates the feasibility of using dark fermentation (DF) to convert the OFMSW to volatile fatty acids (VFAs), fertilizer and H2. The VFAs in the DF effluent can be used directly as substrate for subsequent bioprocesses or purified from the effluent for industrial use. DF of the OFMSW in Abu Dhabi will be economically sustainable once VFA purification can be accomplished on large scale for less than 15USD/m(3)(effluent). With a VFA minimum selling price of 330 USD/tCOD, DF provides a competitive carbon source to sugar. Furthermore, DF is likely to use less energy than conventional processes that produce VFAs, fertilizer and H2. This makes DF of OFMSW a promising waste treatment technology and biorefinery platform. PMID:25840736

  19. Performance evaluation of a large-scale optical switch based on an arrayed waveguide grating router and wavelength converter

    NASA Astrophysics Data System (ADS)

    Zhou, Luying; Xu, Zhaowen

    2016-02-01

    A scheduling scheme for a large-scale optical switch is presented and its performance is evaluated. The optical switch is built on an arrayed waveguide grating router (AWGR) and space switching enabled tunable wavelength converter (SS-TWC) and in a Clos switch structure. The SS-TWC has more than one output and in the switch structure enables a multiple fold expansion of the switch port count while using the same dimension AWGR. The switch reconfiguration is triggered by an event, e.g., packet arriving or input port transmitter available for its waiting packets, and the scheduling scheme operates asynchronously. Simulation results demonstrate that the traffic scheduling scheme enables the delivery of high-transmission bandwidth and low packet delay performance, and verify the nonblocking property of the switch.

  20. Note: All-digital CMOS MOS-capacitor-based pulse-shrinking mechanism suitable for time-to-digital converters

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Chi; Hwang, Chorng-Sii; Lin, You-Ting; Liu, Keng-Chih

    2015-12-01

    This paper presents an all-digital CMOS pulse-shrinking mechanism suitable for time-to-digital converters (TDCs). A simple MOS capacitor is used as a pulse-shrinking cell to perform time attenuation for time resolving. Compared with a previous pulse-shrinking mechanism, the proposed mechanism provides an appreciably improved temporal resolution with high linearity. Furthermore, the use of a binary-weighted pulse-shrinking unit with scaled MOS capacitors is proposed for achieving a programmable resolution. A TDC involving the proposed mechanism was fabricated using a TSMC (Taiwan Semiconductor Manufacturing Company) 0.18-μm CMOS process, and it has a small area of nearly 0.02 mm2 and an integral nonlinearity error of ±0.8 LSB for a resolution of 24 ps.

  1. Fundamental Study for Introduction of Renewable Energy into Syowa Base

    NASA Astrophysics Data System (ADS)

    Nishikawa, Shogo; Abiko, Haruhiko; Kurihara, Junichi; Ishizawa, Kenji; Endo, Nobuhiko

    To reduce the volume of fuel consumed at Syowa base in Antarctica, we study the proper renewable energy system (RE system) to supply both electrical and thermal energy. Though a lot of photovoltaic power generation systems (PV systems) and wind power generation systems (WG systems) have already been installed all over the world, climate is quite different from other area and we have few experiences on renewable energy system in Antarctica. Moreover, though thermal load is much bigger than electrical load all the year round, both PV system and WG system generate only electrical energy. Therefore we proposed a power supply system composed of PV, WG and heat pump to convert a part of electrical energy to thermal energy. It is important to clear the proper system capacity, operational method of heat pump in this system. As a first step, we studied those items on this system without energy storage system by a simulation. We found that proper operational method of heat pump is affected by capacity of RE system and WG system is useful more than PV system.

  2. Photovoltaic converters for solar-pumped lasers

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Heinbockel, John H.

    1988-01-01

    The authors describe a mathematical parametric study of converters used to convert laser radiation to electricity for space-based laser power systems. Two different lasers, the 1.06-micron Nd laser and the 1.315-micron iodine laser, are used in the vertical junction converter. The calculated efficiency is 50 percent for a 100-junction Si photovoltaic converter when used with a Nd laser. The calculated efficiency for a 1000-junction Ga(0.53)In(0.47)As photovoltaic converter is 43 percent when used with an iodine laser.

  3. Harvesting human kinematical energy based on liquid metal magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Jia, Dewei; Liu, Jing; Zhou, Yixin

    2009-03-01

    A flexible human energy harvesting generator - Liquid Metal Magnetohydrodynamics Generator (LMMG) is proposed and fabricated. Conceptual experiments were performed to investigate this electricity harvesting principle. Theoretical analysis predicts that the present method is promising at converting otherwise wasted human kinematical energy via a directional selective generation paradigm. In vitro experiment demonstrates output of 1.4 V/3.61 μW by 5.68 g Ga 62In 25Sn 13 liquid metal with a rather high efficiency of more than 45%. The in vivo experiment actuated by a wrist swing during brisk walking with the plastic valve to rectify the flow, verified the potentiality of unidirectional actuation. This concept based on the flexible movement of LMMG is robust to supply electricity which would be important for future wearable micro/nano devices as a voltage constrained charge provider.

  4. A Resource Assessment Of Geothermal Energy Resources For Converting Deep Gas Wells In Carbonate Strata Into Geothermal Extraction Wells: A Permian Basin Evaluation

    SciTech Connect

    Erdlac, Richard J., Jr.

    2006-10-12

    Previously conducted preliminary investigations within the deep Delaware and Val Verde sub-basins of the Permian Basin complex documented bottom hole temperatures from oil and gas wells that reach the 120-180C temperature range, and occasionally beyond. With large abundances of subsurface brine water, and known porosity and permeability, the deep carbonate strata of the region possess a good potential for future geothermal power development. This work was designed as a 3-year project to investigate a new, undeveloped geographic region for establishing geothermal energy production focused on electric power generation. Identifying optimum geologic and geographic sites for converting depleted deep gas wells and fields within a carbonate environment into geothermal energy extraction wells was part of the project goals. The importance of this work was to affect the three factors limiting the expansion of geothermal development: distribution, field size and accompanying resource availability, and cost. Historically, power production from geothermal energy has been relegated to shallow heat plumes near active volcanic or geyser activity, or in areas where volcanic rocks still retain heat from their formation. Thus geothermal development is spatially variable and site specific. Additionally, existing geothermal fields are only a few 10’s of square km in size, controlled by the extent of the heat plume and the availability of water for heat movement. This plume radiates heat both vertically as well as laterally into the enclosing country rock. Heat withdrawal at too rapid a rate eventually results in a decrease in electrical power generation as the thermal energy is “mined”. The depletion rate of subsurface heat directly controls the lifetime of geothermal energy production. Finally, the cost of developing deep (greater than 4 km) reservoirs of geothermal energy is perceived as being too costly to justify corporate investment. Thus further development opportunities

  5. Converting Chemical Energy to Electricity through a Three-Jaw Mini-Generator Driven by the Decomposition of Hydrogen Peroxide.

    PubMed

    Xiao, Meng; Wang, Lei; Ji, Fanqin; Shi, Feng

    2016-05-11

    Energy conversion from a mechanical form to electricity is one of the most important research advancements to come from the horizontal locomotion of small objects. Until now, the Marangoni effect has been the only propulsion method to produce the horizontal locomotion to induce an electromotive force, which is limited to a short duration because of the specific property of surfactants. To solve this issue, in this article we utilized the decomposition of hydrogen peroxide to provide the propulsion for a sustainable energy conversion from a mechanical form to electricity. We fabricated a mini-generator consisting of three parts: a superhydrophobic rotator with three jaws, three motors to produce a jet of oxygen bubbles to propel the rotation of the rotator, and three magnets integrated into the upper surface of the rotator to produce the magnet flux. Once the mini-generator was placed on the solution surface, the motor catalyzed the decomposition of hydrogen peroxide. This generated a large amount of oxygen bubbles that caused the generator and integrated magnets to rotate at the air/water interface. Thus, the magnets passed under the coil area and induced a change in the magnet flux, thus generating electromotive forces. We also investigated experimental factors, that is, the concentration of hydrogen peroxide and the turns of the solenoid coil, and found that the mini-generator gave the highest output in a hydrogen peroxide solution with a concentration of 10 wt % and under a coil with 9000 turns. Through combining the stable superhydrophobicity and catalyst, we realized electricity generation for a long duration, which could last for 26 000 s after adding H2O2 only once. We believe this work provides a simple process for the development of horizontal motion and provides a new path for energy reutilization. PMID:27093949

  6. Twisted Savonius turbine based marine current energy conversion system

    NASA Astrophysics Data System (ADS)

    Hassan, Md. Imtiaj

    The Ocean Network Seafloor Instrumentation (ONSFI) Project is a multidisciplinary research and development project that aims to design, fabricate and validate a proof-of-concept seafloor array of wireless marine sensors for use in monitoring seabed processes. The sensor pods, known as Seaformatics, will be powered by ocean bottom currents and will be able to communicate with each other and to the Internet through surface master units to facilitate observation of the ocean floor from the shore. This thesis explores the use of the twisted Savonius turbine as a means of converting the kinetic energy of the free flowing water into electrical energy for the pods. This will eliminate the need for battery replacement. A physical model of the turbine was constructed and tested in the Water Flume at the Marine Institute of Memorial University and in the Wind Tunnel in the Engineering Building at Memorial University. A mathematical model of the turbine was constructed in SolidWorks. This was tested in the Computational Fluid Dynamics or CFD software FLOW-3D. Experimental results were compared with CFD results and the agreement was reasonable. A twisted Savonius turbine emulator was developed to test a dc-dc boost converter. A low cost microcontroller based MPPT algorithm was developed to obtain maximum power from the turbine. Overall the thesis shows that the twisted Savonius turbine can provide the power needed by the sensor pods. It also shows that CFD is a viable way to study the performance of the Savonius type of turbine.

  7. Broadband wavelength converters with flattop responses based on cascaded second-harmonic generation and difference frequency generation in Bessel-chirped gratings.

    PubMed

    Liu, Tao; Djordjevic, Ivan B; Song, Zekun; Chen, Ying; Zhang, Rongxiang; Zhang, Ke; Zhao, Wei; Li, Baogang

    2016-05-16

    We investigate ultra-broadband wavelength converters based on cascaded second-harmonic generation and difference frequency generation using Bessel-chirped gratings (BCGs) in lithium niobate waveguides, and compare them to the ones using uniform grating and segmented grating, respectively. For the same length and power, the BCGs show broader bandwidth than the other two types of grating. The ripple of the matching response is very small as well. Analysis also shows that almost the same conversion bandwidth and maximum conversion efficiency with tolerant response flatness can be achieved when the manufacturing tolerance of the waveguide length is smaller than 0.1 cm. PMID:27409916

  8. Rotorcraft convertible engine study

    NASA Technical Reports Server (NTRS)

    Gill, J. C.; Earle, R. V.; Mar, H. M.

    1982-01-01

    The objective of the Rotorcraft Convertible Engine Study was to define future research and technology effort required for commercial development by 1988 of convertible fan/shaft gas turbine engines for unconventional rotorcraft transports. Two rotorcraft and their respective missions were defined: a Fold Tilt Rotor aircraft and an Advancing Blade Concept (ABC) rotorcraft. Sensitivity studies were conducted with these rotorcraft to determine parametrically the influence of propulsion characteristics on aircraft size, mission fuel requirements, and direct operating costs (DOC). The two rotorcraft were flown with conventional propulsion systems (separate lift/cruise engines) and with convertible propulsion systems to determine the benefits to be derived from convertible engines. Trade-off studies were conducted to determine the optimum engine cycle and staging arrangement for a convertible engine. Advanced technology options applicable to convertible engines were studied. Research and technology programs were identified which would ensure technology readiness for commercial development of convertible engines by 1988.

  9. High efficiency thermionic converter studies

    NASA Technical Reports Server (NTRS)

    Huffman, F. N.; Sommer, A. H.; Balestra, C. L.; Briere, T. R.; Lieb, D.; Oettinger, P. E.; Goodale, D. B.

    1977-01-01

    Research in thermionic energy conversion technology is reported. The objectives were to produce converters suitable for use in out of core space reactors, radioisotope generators, and solar satellites. The development of emitter electrodes that operate at low cesium pressure, stable low work function collector electrodes, and more efficient means of space charge neutralization were investigated to improve thermionic converter performance. Potential improvements in collector properties were noted with evaporated thin film barium oxide coatings. Experiments with cesium carbonate suggest this substance may provide optimum combinations of cesium and oxygen for thermionic conversion.

  10. The Value of the Energy Data Base.

    ERIC Educational Resources Information Center

    King, Donald W.; And Others

    A study was conducted to assess the value of the Energy Data Base (EDB), which is produced by the Technical Information Center (TIC) of the Department of Energy (DOE) in order to provide a means of identifying primary energy information sources, particularly journal articles and technical reports. The volume of energy information distributed to…

  11. Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system

    NASA Astrophysics Data System (ADS)

    Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

    2014-03-01

    Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper.

  12. Luminescent and transparent nanopaper based on rare-earth up-converting nanoparticle grafted nanofibrillated cellulose derived from garlic skin.

    PubMed

    Zhao, Jingpeng; Wei, Zuwu; Feng, Xin; Miao, Miao; Sun, Lining; Cao, Shaomei; Shi, Liyi; Fang, Jianhui

    2014-09-10

    Highly flexible, transparent, and luminescent nanofibrillated cellulose (NFC) nanopaper with heterogeneous network, functionalized by rare-earth up-converting luminescent nanoparticles (UCNPs), was rapidly synthesized by using a moderate pressure extrusion paper-making process. NFC was successfully prepared from garlic skin using an efficient extraction approach combined with high frequency ultrasonication and high pressure homogenization after removing the noncellulosic components. An efficient epoxidation treatment was carried out to enhance the activity of the UCNPs (NaYF4:Yb,Er) with oleic acid ligand capped on the surface. The UCNPs after epoxidation then reacted with NFC in aqueous medium to form UCNP-grafted NFC nanocomposite (NFC-UCNP) suspensions at ambient temperature. Through the paper-making process, the assembled fluorescent NFC-UCNP hybrid nanopaper exhibits excellent properties, including high transparency, strong up-conversion luminescence, and good flexibility. The obtained hybrid nanopaper was characterized by transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscope (FE-SEM), up-conversion luminescence (UCL) spectrum, and ultraviolet and visible (UV-vis) spectrophotometer. The experimental results demonstrate that the UCNPs have been successfully grafted to the NFC matrix with heterogeneous network. And the superiorly optical transparent and luminescent properties of the nanopaper mainly depend on the ratio of UCNPs to NFC. Of importance here is that, NFC and UCNPs afford the nanopaper a prospective candidate for multimodal anti-counterfeiting, sensors, and ion probes applications. PMID:25116651

  13. Synchronization sampling method based on delta-sigma analog-digital converter for underwater towed array system.

    PubMed

    Jiang, Jia-Jia; Duan, Fa-Jie; Li, Yan-Chao; Hua, Xiang-Ning

    2014-03-01

    Synchronization sampling is very important in underwater towed array system where every acquisition node (AN) samples analog signals by its own analog-digital converter (ADC). In this paper, a simple and effective synchronization sampling method is proposed to ensure synchronized operation among different ANs of the underwater towed array system. We first present a master-slave synchronization sampling model, and then design a high accuracy phase-locked loop to synchronize all delta-sigma ADCs to a reference clock. However, when the master-slave synchronization sampling model is used, both the time-delay (TD) of messages traveling along the wired transmission medium and the jitter of the clocks will bring out synchronization sampling error (SSE). Therefore, a simple method is proposed to estimate and compensate the TD of the messages transmission, and then another effective method is presented to overcome the SSE caused by the jitter of the clocks. An experimental system with three ANs is set up, and the related experimental results verify the validity of the synchronization sampling method proposed in this paper. PMID:24689606

  14. A single-phase multi-level D-STATCOM inverter using modular multi-level converter (MMC) topology for renewable energy sources

    NASA Astrophysics Data System (ADS)

    Sotoodeh, Pedram

    This dissertation presents the design of a novel multi-level inverter with FACTS capability for small to mid-size (10-20kW) permanent-magnet wind installations using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with D-STATCOM option to provide utilities with more control on active and reactive power transfer of distribution lines. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to fix the power factor of the grid at a target value, regardless of wind speed, by regulating active and reactive power required by the grid. The inverter is capable of controlling active and reactive power by controlling the phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without additional cost. Simulations of the proposed inverter, with 5 and 11 levels, have been conducted in MATLAB/Simulink for two systems including 20 kW/kVAR and 250 W/VAR. To validate the simulation results, a scaled version (250 kW/kVAR) of the proposed inverter with 5 and 11 levels has been built and tested in the laboratory. Experimental results show that the reduced-scale 5- and 11-level inverter is able to fix PF of the grid as well as being compatible with IEEE standards. Furthermore, total cost of the prototype models, which is one of the major objectives of this research, is comparable with market prices.

  15. Demonstration of the Recent Additions in Modeling Capabilities for the WEC-Sim Wave Energy Converter Design Tool: Preprint

    SciTech Connect

    Tom, N.; Lawson, M.; Yu, Y. H.

    2015-03-01

    WEC-Sim is a mid-fidelity numerical tool for modeling wave energy conversion (WEC) devices. The code uses the MATLAB SimMechanics package to solve the multi-body dynamics and models the wave interactions using hydrodynamic coefficients derived from frequency domain boundary element methods. In this paper, the new modeling features introduced in the latest release of WEC-Sim will be presented. The first feature discussed is the conversion of the fluid memory kernel to a state-space approximation that provides significant gains in computational speed. The benefit of the state-space calculation becomes even greater after the hydrodynamic body-to-body coefficients are introduced as the number of interactions increases exponentially with the number of floating bodies. The final feature discussed is the capability toadd Morison elements to provide additional hydrodynamic damping and inertia. This is generally used as a tuning feature, because performance is highly dependent on the chosen coefficients. In this paper, a review of the hydrodynamic theory for each of the features is provided and successful implementation is verified using test cases.

  16. Paper-based energy harvesting from salinity gradients.

    PubMed

    Chang, Hyung-Kwan; Choi, Eunpyo; Park, Jungyul

    2016-02-21

    Paper-based microfluidic devices have many advantages such as low cost, flexibility, light weight and easy disposability. Especially, since they can intrinsically generate capillary-driven flow (no pumps are needed), paper-based microfluidic devices are widely used in analytical or diagnostic platforms. Along with advancements in microfluidic paper-based analytical devices (μPADs), energy generation using paper materials has received significant attention. In this study, environment-friendly and flexible paper-based energy harvesting with a simple configuration is demonstrated by using the principle of reverse electrodialysis (RED). RED is a promising clean energy generation method, which converts Gibbs free energy into electricity by salinity gradients without discharging any pollutants. However, the power efficiency in a conventional RED device is limited by the essential requirement of active pumping for providing high and low concentration electrolytes. Capillary pumping from the proposed paper-based RED can save this waste of energy, and moreover, the flexible device is realized with cost effective materials and a simple fabrication step, and is environmentally friendly. By thoughtful analysis of voltage-current experiments and capillary flow rates in paper channels, the optimized channel width interfacing with a selective membrane is determined as 2 mm and the maximum power and power density are achieved as 55 nW and 275 nW cm(-2), respectively. 25.8% of the generated maximum power is successfully saved by realizing the pumpless RED system. This paper-based RED device can be integrated directly with μPADs as a practical application. PMID:26768119

  17. Langevin power curve analysis for numerical wind energy converter models with new insights on high frequency power performance

    NASA Astrophysics Data System (ADS)

    Mücke, Tanja A.; Wächter, Matthias; Milan, Patrick; Peinke, Joachim

    2015-11-01

    Based on the Langevin equation it has been proposed to obtain power curves for wind turbines from high frequency data of wind speed measurements u(t) and power output P (t). The two parts of the Langevin approach, power curve and drift field, give a comprehensive description of the conversion dynamic over the whole operating range of the wind turbine. The method deals with high frequent data instead of 10 min means. It is therefore possible to gain a reliable power curve already from a small amount of data per wind speed. Furthermore, the method is able to visualize multiple fixed points, which is e.g. characteristic for the transition from partial to full load or in case the conversion process deviates from the standard procedures. In order to gain a deeper knowledge it is essential that the method works not only for measured data but also for numerical wind turbine models and synthetic wind fields. Here, we characterize the dynamics of a detailed numerical wind turbine model and calculate the Langevin power curve for different data samplings. We show, how to get reliable results from synthetic data and verify the applicability of the method for field measurements with ultra-sonic, cup and Lidar measurements. The independence of the fixed points on site specific turbulence effects is also confirmed with the numerical model. Furthermore, we demonstrate the potential of the Langevin approach to detect failures in the conversion process and thus show the potential of the Langevin approach for a condition monitoring system.

  18. Interleaved power converter

    DOEpatents

    Zhu, Lizhi

    2007-11-13

    A power converter architecture interleaves full bridge converters to alleviate thermal management problems in high current applications, and may, for example, double the output power capability while reducing parts count and costs. For example, one phase of a three phase inverter is shared between two transformers, which provide power to a rectifier such as a current doubler rectifier to provide two full bridge DC/DC converters with three rather than four high voltage inverter legs.

  19. ITER convertible blanket evaluation

    SciTech Connect

    Wong, C.P.C.; Cheng, E.

    1995-09-01

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.

  20. The photoelectric displacement converter

    NASA Astrophysics Data System (ADS)

    Dragoner, Valeriu V.

    2005-02-01

    In the article are examined questions of constructing photoelectric displacement converter satisfying demands that are stated above. Converter has channels of approximate and precise readings. The approximate reading may be accomplished either by the method of reading from a code mask or by the method of the consecutive calculation of optical scale gaps number. Phase interpolator of mouar strips" gaps is determined as a precise measuring. It is shown mathematical model of converter that allow evaluating errors and operating speed of conversion.

  1. A Multi-Level Grid Interactive Bi-directional AC/DC-DC/AC Converter and a Hybrid Battery/Ultra-capacitor Energy Storage System with Integrated Magnetics for Plug-in Hybrid Electric Vehicles

    SciTech Connect

    Onar, Omer C

    2011-01-01

    This study presents a bi-directional multi-level power electronic interface for the grid interactions of plug-in hybrid electric vehicles (PHEVs) as well as a novel bi-directional power electronic converter for the combined operation of battery/ultracapacitor hybrid energy storage systems (ESS). The grid interface converter enables beneficial vehicle-to-grid (V2G) interactions in a high power quality and grid friendly manner; i.e, the grid interface converter ensures that all power delivered to/from grid has unity power factor and almost zero current harmonics. The power electronic converter that provides the combined operation of battery/ultra-capacitor system reduces the size and cost of the conventional ESS hybridization topologies while reducing the stress on the battery, prolonging the battery lifetime, and increasing the overall vehicle performance and efficiency. The combination of hybrid ESS is provided through an integrated magnetic structure that reduces the size and cost of the inductors of the ESS converters. Simulation and experimental results are included as prove of the concept presenting the different operation modes of the proposed converters.

  2. Pulsed thermionic converter study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A nuclear electric propulsion concept using a thermionic reactor inductively coupled to a magnetoplasmadynamic accelerator (MPD arc jet) is described, and the results of preliminary analyses are presented. In this system, the MPD thruster operates intermittently at higher voltages and power levels than the thermionic generating unit. A typical thrust pulse from the MPD arc jet is characterized by power levels of 1 to 4 MWe, a duration of 1 msec, and a duty cycle of approximately 20%. The thermionic generating unit operates continuously but with a lower power level of approximately 0.4 MWe. Energy storage between thrust pulses is provided by building up a large current in an inductor using the output of the thermionic converter array. Periodically, the charging current is interrupted, and the energy stored in the magnetic field of the inductor is utilized for a short duration thrust pulse. The results of the preliminary analysis show that a coupling effectiveness of approximately 85 to 90% is feasible for a nominal 400 KWe system with an inductive unit suitable for a flight vehicle.

  3. Estimation of channel mismatches in time-interleaved analog-to-digital converters based on fractional delay and sine curve fitting.

    PubMed

    Guo, Lianping; Tian, Shulin; Jiang, Jun

    2015-03-01

    This paper proposes an algorithm to estimate the channel mismatches in time-interleaved analog-to-digital converter (TIADC) based on fractional delay (FD) and sine curve fitting. Choose one channel as the reference channel and apply FD to the output samples of reference channel to obtain the ideal samples of non-reference channels with no mismatches. Based on least square method, the sine curves are adopted to fit the ideal and the actual samples of non-reference channels, and then the mismatch parameters can be estimated by comparing the ideal sine curves and the actual ones. The principle of this algorithm is simple and easily understood. Moreover, its implementation needs no extra circuits, lowering the hardware cost. Simulation results show that the estimation accuracy of this algorithm can be controlled within 2%. Finally, the practicability of this algorithm is verified by the measurement results of channel mismatch errors of a two-channel TIADC prototype. PMID:25832264

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.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

  5. EMR modelling of a hydrogen-based electrical energy storage

    NASA Astrophysics Data System (ADS)

    Agbli, K. S.; Hissel, D.; Péra, M.-C.; Doumbia, I.

    2011-05-01

    This paper deals with multi-physics modelling of the stationary system. This modelling is the first step to reach the fuel cell system dimensioning aim pursued. Besides this modelling approach based on the stationary energetic system, the novelty in this paper is both the new approach of the photovoltaic EMR modelling and the EMR of the hydrogen storage process. The granular modelling approach is used to model each component of the system. Considering a stand alone PEM fuel cell system, hydrogen is expected to be produced and stored on the spot from renewable energy (photovoltaic) in order to satisfy the fuel availability. In fact, to develop a generic and modular model, energetic macroscopic representation (EMR) is used as graphical modelling tool. Allowing to be easily grasped by the experts even not necessarily gotten used to the modelling formalism, EMR is helpful to model the multi-domains energetic chain. The solar energy through solar module is converted in electrical energy; part of this energy is transformed in chemical energy (hydrogen) thanks to an electrolyser. Then the hydrogen is compressed into a tank across a storage system. The latter part of the solar module energy is stored as electrical energy within supercapacitor or lead-acid battery. Using the modularity feature of the EMR, the whole system is modelled entity by entity; afterwards by putting them together the overall system has been reconstructed. According to the scale effect of the system entities, some simulation and/or experimental results are given. Given to the different aims which are pursued in the sustainable energy framework like prediction, control and optimisation, EMR modelling approach is a reliable option for the energy management in real time of energetic system in macroscopic point of view.

  6. Lignin Based Carbon Materials for Energy Storage Applications

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori; Rios, Orlando; Johs, Alexander

    2014-01-01

    The implementation of Li-ion battery technology into electric and hybrid electric vehicles and portable electronic devices such as smart phones, laptops and tablets, creates a demand for efficient, economic and sustainable materials for energy storage. However, the high cost and long processing time associated with manufacturing battery-grade anode and cathode materials are two big constraints for lowering the total cost of batteries and environmentally friendly electric vehicles. Lignin, a byproduct of the pulp and paper industry and biorefinery, is one of the most abundant and inexpensive natural biopolymers. It can be efficiently converted to low cost carbon fibers with optimal properties for use as anode materials. Recent developments in the preparation of lignin precursors and conversion to carbon fiber-based anode materials have created a new class of anode materials with excellent electrochemical characteristics suitable for immediate use in existing Li- or Na-ion battery technologies.

  7. Experimental study of the lift and drag characteristics of a cascade of flat plates in a configuration of interest for tidal energy converters

    NASA Astrophysics Data System (ADS)

    Fedoul, Faical; Parras, Luis; Del Pino, Carlos; Fernandez-Feria, Ramon

    2012-11-01

    Wind tunnel experiments are conducted for the flow around both a single flat plate and a cascade of three parallel flat plates at different angles of incidence to compare their lift and drag coefficients in a range of Reynolds number about 105, and for two values of the aspect ratio of the flat plates. The selected cascade configuration is of interest for a particular type of tidal energy converter. The lift and drag characteristics of the central plate in the cascade are compared to those of the isolated plate, finding that there exist an angle of incidence, which depends on the Reynolds number and the aspect ratio, above which the effective lift of the plate in the cascade becomes larger than that of an isolated plate. These experimental results, which are also analyzed in the light of theoretical predictions, are used as a guide for the design of the optimum configuration of the cascade which extracts the maximum power from a tidal current for a given value of the Reynolds number. Supported by the Ministerio de Ciencia e Innovacion (Spain) Grant no. ENE2010-16851.

  8. Energy Conservation in Agriculture. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Lawrence, Layle D.

    This competency-based energy conservation in agriculture curriculum for grades 11 and 12 is organized into seven modules. Intended for use for individualized or group instruction, the lessons should fit into existing units in courses of study rather than be presented as a single comprehensive energy conservation unit. Each module is based on from…

  9. High energy sodium based room temperature flow batteries

    NASA Astrophysics Data System (ADS)

    Shamie, Jack

    As novel energy sources such as solar, wind and tidal energies are explored it becomes necessary to build energy storage facilities to load level the intermittent nature of these energy sources. Energy storage is achieved by converting electrical energy into another form of energy. Batteries have many properties that are attractive for energy storage including high energy and power. Among many different types of batteries, redox flow batteries (RFBs) offer many advantages. Unlike conventional batteries, RFBs store energy in a liquid medium rather than solid active materials. This method of storage allows for the separation of energy and power unlike conventional batteries. Additionally flow batteries may have long lifetimes because there is no expansion or contraction of electrodes. A major disadvantage of RFB's is its lower energy density when compared to traditional batteries. In this Thesis, a novel hybrid Na-based redox flow battery (HNFB) is explored, which utilizes a room temperature molten sodium based anode, a sodium ion conducting solid electrolyte and liquid catholytes. The sodium electrode leads to high voltages and energy and allows for the possibility of multi-electron transfer per molecule. Vanadium acetylacetonate (acac) and TEMPO have been investigated for their use as catholytes. In the vanadium system, 2 electrons transfers per vanadium atom were found leading to a doubling of capacity. In addition, degradation of the charged state was found to be reversible within the voltage range of the cell. Contamination by water leads to the formation of vanadyl acetylacetonate. Although it is believed that vanadyl complex need to be taken to low voltages to be reduced back to vanadium acac, a new mechanism is shown that begins at higher voltages (2.1V). Vanadyl complexes react with excess ligand and protons to reform the vanadium complex. During this reaction, water is reformed leading to the continuous cycle in which vanadyl is formed and then reduced back

  10. Cascaded resonant bridge converters

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  11. Pyroelectric energy harvesting using liquid-based switchable thermal interfaces

    SciTech Connect

    Cha, G; Ju, YS

    2013-01-15

    The pyroelectric effect offers an intriguing solid-state approach for harvesting ambient thermal energy to power distributed networks of sensors and actuators that are remotely located or otherwise difficult to access. There have been, however, few device-level demonstrations due to challenges in converting spatial temperature gradients into temporal temperature oscillations necessary for pyroelectric energy harvesting. We demonstrate the feasibility of a device concept that uses liquid-based thermal interfaces for rapid switching of the thermal conductance between a pyroelectric material and a heat source/sink and can thereby deliver high output power density. Using a thin film of a pyroelectric co-polymer together with a macroscale mechanical actuator, we operate pyroelectric thermal energy harvesting cycles at frequencies close to 1 Hz. Film-level power densities as high as 110 mW/cm(3) were achieved, limited by slow heat diffusion across a glass substrate. When combined with a laterally interdigitated electrode array and a MEMS actuator, the present design offers an attractive option for compact high-power density thermal energy harvesters. (C) 2012 Elsevier B.V. All rights reserved.

  12. Passive Resonant Bidirectional Converter with Galvanic Barrier

    NASA Technical Reports Server (NTRS)

    Rosenblad, Nathan S. (Inventor)

    2014-01-01

    A passive resonant bidirectional converter system that transports energy across a galvanic barrier includes a converter using at least first and second converter sections, each section including a pair of transfer terminals, a center tapped winding; a chopper circuit interconnected between the center tapped winding and one of the transfer terminals; an inductance feed winding interconnected between the other of the transfer terminals and the center tap and a resonant tank circuit including at least the inductance of the center tap winding and the parasitic capacitance of the chopper circuit for operating the converter section at resonance; the center tapped windings of the first and second converter sections being disposed on a first common winding core and the inductance feed windings of the first and second converter sections being disposed on a second common winding core for automatically synchronizing the resonant oscillation of the first and second converter sections and transferring energy between the converter sections until the voltage across the pairs of transfer terminals achieves the turns ratio of the center tapped windings.

  13. Power Converters Secure Electronics in Harsh Environments

    NASA Technical Reports Server (NTRS)

    2013-01-01

    In order to harden power converters for the rigors of space, NASA awarded multiple SBIR contracts to Blacksburg, Virginia-based VPT Inc. The resulting hybrid DC-DC converters have proven valuable in aerospace applications, and as a result the company has generated millions in revenue from the product line and created four high-tech jobs to handle production.

  14. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOEpatents

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  15. Radiation Effects on DC-DC Converters

    NASA Technical Reports Server (NTRS)

    Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2001-01-01

    In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25

  16. Conclusions. [hydrogen-based energy

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Conclusions are presented according to general areas of technology with some specific examples of research and technology needs identified. These conclusions provide a base for the future development of detailed program plans and identify research needs that are not being given attention or are not being supported at a sufficient level. Emphasis is placed on hydrogen production and use.

  17. Digital scale converter

    DOEpatents

    Upton, Richard G.

    1978-01-01

    A digital scale converter is provided for binary coded decimal (BCD) conversion. The converter may be programmed to convert a BCD value of a first scale to the equivalent value of a second scale according to a known ratio. The value to be converted is loaded into a first BCD counter and counted down to zero while a second BCD counter registers counts from zero or an offset value depending upon the conversion. Programmable rate multipliers are used to generate pulses at selected rates to the counters for the proper conversion ratio. The value present in the second counter at the time the first counter is counted to the zero count is the equivalent value of the second scale. This value may be read out and displayed on a conventional seven-segment digital display.

  18. High heat flux experiment on B4C-converted carbon based materials for plasma facing materials of JT-60U

    NASA Astrophysics Data System (ADS)

    Nakamura, Kazuyuki; Ishikawa, Hiroshi; Ando, Toshiro; Satoh, Kazuyoshi; Yokoyama, Kenji; Suzuki, Satoshi; Dairakum, Masayuki; Araki, Masanori; Akiba, Masato

    1994-03-01

    High heat flux experiments have been previously carried out on three kinds, namely low pressure plasma spray (LPPS), chemical vapor deposition (CVD) and conversion (CVR) methods, of B4C-overlaid CFC's using the JAERI electron beam irradiation system (JEBIS). As a result, it turned out that CVR method has the best adhesion property between B4C layer and bulk carbon. However, thicker B4C layer is necessary to use in long period as the divertor tiles of JT-60U. The purpose of this experiment is to investigate the thermal property of B4C-converted carbon based materials which have thicker B4C layer than the previous experiments. Irradiations were performed under two different heating conditions, namely in the normal condition (5-20 MW/m(exp 2), 5 s) and in the disruption conditions (1100-1600 MW/m(exp 2), 2-3 ms). The dimensions of the samples were 25 mm x 25 mm x 25 mm, and B4C-converted layers were made on the three kinds of CFC's and fifth kinds of isotropic graphites. The thickness of B4C layer was 150-1300 (mu)m. Measurements were made with respect to the weight loss, changes of the surface morphology and the surface temperature. In the normal condition, the damages such as surface melting and exfoliation were not observed on the samples which have B4C layer below 600 (mu)m in thickness. In the disruption condition, melting and exfoliation were observed on the surfaces of the samples whose substrates were PD-330S, PD-600S and HCB-5S, and melting was observed on the surfaces of the samples whose substrates were PCC-2S, MFC-1, MCI-felt, ETP-10 and STP-60. It is considered that the porous layer in the B4C layer caused the severe exfoliation from the measurement of the surface composition.

  19. Design challenges of EO polymer based leaky waveguide deflector for 40 Gs/s all-optical analog-to-digital converters

    NASA Astrophysics Data System (ADS)

    Hadjloum, Massinissa; El Gibari, Mohammed; Li, Hongwu; Daryoush, Afshin S.

    2016-08-01

    Design challenges and performance optimization of an all-optical analog-to-digital converter (AOADC) is presented here. The paper addresses both microwave and optical design of a leaky waveguide optical deflector using electro-optic (E-O) polymer. The optical deflector converts magnitude variation of the applied RF voltage into variation of deflection angle out of a leaky waveguide optical beam using the linear E-O effect (Pockels effect) as part of the E-O polymer based optical waveguide. This variation of deflection angle as result of the applied RF signal is then quantized using optical windows followed by an array of high-speed photodetectors. We optimized the leakage coefficient of the leaky waveguide and its physical length to achieve the best trade-off between bandwidth and the deflected optical beam resolution, by improving the phase velocity matching between lightwave and microwave on one hand and using pre-emphasis technique to compensate for the RF signal attenuation on the other hand. In addition, for ease of access from both optical and RF perspective, a via-hole less broad bandwidth transition is designed between coplanar pads and coupled microstrip (CPW-CMS) driving electrodes. With the best reported E-O coefficient of 350 pm/V, the designed E-O deflector should allow an AOADC operating over 44 giga-samples-per-seconds with an estimated effective resolution of 6.5 bits on RF signals with Nyquist bandwidth of 22 GHz. The overall DC power consumption of all components used in this AOADC is of order of 4 W and is dominated by power consumption in the power amplifier to generate a 20 V RF voltage in 50 Ohm system. A higher sampling rate can be achieved at similar bits of resolution by interleaving a number of this elementary AOADC at the expense of a higher power consumption.

  20. 2 Gbit/s data transmission from an unfiltered laser-based phosphor-converted white lighting communication system.

    PubMed

    Lee, Changmin; Shen, Chao; Oubei, Hassan M; Cantore, Michael; Janjua, Bilal; Ng, Tien Khee; Farrell, Robert M; El-Desouki, Munir M; Speck, James S; Nakamura, Shuji; Ooi, Boon S; DenBaars, Steven P

    2015-11-16

    We demonstrate data transmission of unfiltered white light generated by direct modulation of a blue gallium nitride (GaN) laser diode (LD) exciting YAG:Ce phosphors. 1.1 GHz of modulation bandwidth was measured without a limitation from the slow 3.8 MHz phosphor response. A high data transmission rate of 2 Gbit/s was achieved without an optical blue-filter using a non-return-to-zero on-off keying (NRZ-OOK) modulation scheme. The measured bit error rate (BER) of 3.50 × 10(-3) was less than the forward error correction (FEC) limit of 3.8 × 10(-3). The generated white light exhibits CIE 1931 chromaticity coordinates of (0.3628, 0.4310) with a color rendering index (CRI) of 58 and a correlated color temperature (CCT) of 4740 K when the LD was operated at 300 mA. The demonstrated laser-based lighting system can be used simultaneously for indoor broadband access and illumination applications with good color stability. PMID:26698461

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

    PubMed

    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. PMID:27430282

  2. High-color rendering indices performance of glass based phosphor-converted white light-emitting diodes for solid state lighting

    NASA Astrophysics Data System (ADS)

    Tsai, Chun-Chin; Cheng, Wei-Chih; Chen, Guan-Hao; Lee, Yu-Chun; Kuo, Cheng Ta; Cheng, Wood-Hi

    2014-02-01

    The high-temperature operation of glass based phosphor-converted warm-white light-emitting diodes (PC-WWLEDs) is demonstrated. The fabrication and characteristics of low-temperature phosphor (Yollow:Ce:3+:YAG, Greed:Tb3+:YAG, Red:CaAlClSiN3:Eu2+) doped glass applied to high color rendering indices warm-white-light-emitting diodes was presented. In this property is color coordinates (x, y) = (0.32, 0.28), quantum yield (QY) = 55%, color rending index (CRI) =85, correlated color temperature (CCT) =3900K. The result showed the PC-WLEDs maintained good thermal stability at the high temperature operation. The QY decay, CRI attenuation and chromaticity shift in glass and silicone based high-power PC-WLEDs under thermal aging at 150°C and 250°C are also presented and compared. The result indicated that the glass based PC-WLEDs exhibited better thermal stability than the silicone. And the color rendering indices (CRI) glass phosphor may have potential used as a phosphor layer for high-performance and low-cost PCWLEDs used in next-generation indoors solid-state lighting applications.

  3. Base Program on Energy Related Research

    SciTech Connect

    Western Research Institute

    2008-06-30

    The main objective of the Base Research Program was to conduct both fundamental and applied research that will assist industry in developing, deploying, and commercializing efficient, nonpolluting fossil energy technologies that can compete effectively in meeting the energy requirements of the Nation. In that regard, tasks proposed under the WRI research areas were aligned with DOE objectives of secure and reliable energy; clean power generation; development of hydrogen resources; energy efficiency and development of innovative fuels from low and no-cost sources. The goal of the Base Research Program was to develop innovative technology solutions that will: (1) Increase the production of United States energy resources--coal, natural gas, oil, and renewable energy resources; (2) Enhance the competitiveness of United States energy technologies in international markets and assist in technology transfer; (3) Reduce the nation's dependence on foreign energy supplies and strengthen both the United States and regional economies; and (4) Minimize environmental impacts of energy production and utilization. This report summarizes the accomplishments of the overall Base Program. This document represents a stand-alone Final Report for the entire Program. It should be noted that an interim report describing the Program achievements was prepared in 2003 covering the progress made under various tasks completed during the first five years of this Program.

  4. An electret-based aeroelastic flutter energy harvester

    NASA Astrophysics Data System (ADS)

    Perez, M.; Boisseau, S.; Gasnier, P.; Willemin, J.; Reboud, J. L.

    2015-03-01

    This paper presents a new airflow energy harvester exploiting fluttering effects coupled to an electret-based conversion to turn the flow-induced movements of a membrane into electricity. The proposed device is made of a polymer membrane placed between two parallel flat electrodes coated with 25 μm thick Teflon PTFE electret layers; a bluff body is placed at the inlet of the device to induce vortex shedding. When the wind or airstream of any kind flows through the harvester, the membrane enters in oscillation due to fluttering and successively comes into contact with the two Teflon-coated fixed electrodes. This periodic motion is directly converted into electricity thanks to the electret-based conversion process. Various geometries have been tested and have highlighted a 2.7 cm3 device, with an output power of 481 μW (178 μW cm-3) at 15 m s-1 and 2.1 mW (782 μW cm-3) at 30 m s-1 with an electret charged at -650 V. The power coefficient Cp of the device reaches 0.54% at 15 m s-1 which is low, but compares favorably with the other small-scale airflow energy harvesters.

  5. A multiscale-based approach for composite materials with embedded PZT filaments for energy harvesting

    NASA Astrophysics Data System (ADS)

    El-Etriby, Ahmed E.; Abdel-Meguid, Mohamed E.; Hatem, Tarek M.; Bahei-El-Din, Yehia A.

    2014-03-01

    Ambient vibrations are major source of wasted energy, exploiting properly such vibration can be converted to valuable energy and harvested to power up devices, i.e. electronic devices. Accordingly, energy harvesting using smart structures with active piezoelectric ceramics has gained wide interest over the past few years as a method for converting such wasted energy. This paper provides numerical and experimental analysis of piezoelectric fiber based composites for energy harvesting applications proposing a multi-scale modeling approach coupled with experimental verification. The multi-scale approach suggested to predict the behavior of piezoelectric fiber-based composites use micromechanical model based on Transformation Field Analysis (TFA) to calculate the overall material properties of electrically active composite structure. Capitalizing on the calculated properties, single-phase analysis of a homogeneous structure is conducted using finite element method. The experimental work approach involves running dynamic tests on piezoelectric fiber-based composites to simulate mechanical vibrations experienced by a subway train floor tiles. Experimental results agree well with the numerical results both for static and dynamic tests.

  6. A low-power inverter-based CMOS level-crossing analog-to-digital converter for low-frequency biosignal sensing

    NASA Astrophysics Data System (ADS)

    Tanaka, Suiki; Niitsu, Kiichi; Nakazato, Kazuo

    2016-03-01

    Low-power analog-to-digital conversion is a key technique for power-limited biomedical applications such as power-limited continuous glucose monitoring. However, a conventional uniform-sampling analog-to-digital converter (ADC) is not suitable for nonuniform biosignals. A level-crossing ADC (LC-ADC) is a promising candidate for low-power biosignal processing because of its event-driven properties. The LC-ADC acquires data by level-crossing sampling. When an input signal crosses the threshold level, the LC-ADC samples the signal. The conventional LC-ADC employs a power-hungry comparator. In this paper, we present a low-power inverter-based LC-ADC. By adjusting the threshold level of the inverter, it can be used as a threshold-fixed window comparator. By using the inverter as an alternative to a comparator, power consumption can be markedly reduced. As a result, the total power consumption is successfully reduced by 90% of that of previous LC-ADC. The inverter-based LC-ADC was found to be very suitable for use in power-limited biomedical devices.

  7. Rapid multiplex detection of 10 foodborne pathogens with an up-converting phosphor technology-based 10-channel lateral flow assay

    PubMed Central

    Zhao, Yong; Wang, Haoran; Zhang, Pingping; Sun, Chongyun; Wang, Xiaochen; Wang, Xinrui; Yang, Ruifu; Wang, Chengbin; Zhou, Lei

    2016-01-01

    The rapid high-throughput detection of foodborne pathogens is essential in controlling food safety. In this study, a 10-channel up-converting phosphor technology-based lateral flow (TC-UPT-LF) assay was established for the rapid and simultaneous detection of 10 epidemic foodborne pathogens. Ten different single-target UPT-LF strips were developed and integrated into one TC-UPT-LF disc with optimization. Without enrichment the TC-UPT-LF assay had a detection sensitivity of 104 CFU mL−1 or 105 CFU mL−1 for each pathogen, and after sample enrichment it was 10 CFU/0.6 mg. The assay also showed good linearity, allowing quantitative detection, with a linear fitting coefficient of determination (R2) of 0.916–0.998. The 10 detection channels did not cross-react, so multiple targets could be specifically detected. When 279 real food samples were tested, the assay was highly consistent (100%) with culture-based methods. The results for 110 food samples artificially contaminated with single or multiple targets showed a high detection rate (≥80%) for most target bacteria. Overall, the TC-UPT-LF assay allows the rapid, quantitative, and simultaneous detection of 10 kinds of foodborne pathogens within 20 min, and is especially suitable for the rapid detection and surveillance of foodborne pathogens in food and water. PMID:26884128

  8. Rapid multiplex detection of 10 foodborne pathogens with an up-converting phosphor technology-based 10-channel lateral flow assay.

    PubMed

    Zhao, Yong; Wang, Haoran; Zhang, Pingping; Sun, Chongyun; Wang, Xiaochen; Wang, Xinrui; Yang, Ruifu; Wang, Chengbin; Zhou, Lei

    2016-01-01

    The rapid high-throughput detection of foodborne pathogens is essential in controlling food safety. In this study, a 10-channel up-converting phosphor technology-based lateral flow (TC-UPT-LF) assay was established for the rapid and simultaneous detection of 10 epidemic foodborne pathogens. Ten different single-target UPT-LF strips were developed and integrated into one TC-UPT-LF disc with optimization. Without enrichment the TC-UPT-LF assay had a detection sensitivity of 10(4) CFU mL(-1) or 10(5) CFU mL(-1) for each pathogen, and after sample enrichment it was 10 CFU/0.6 mg. The assay also showed good linearity, allowing quantitative detection, with a linear fitting coefficient of determination (R(2)) of 0.916-0.998. The 10 detection channels did not cross-react, so multiple targets could be specifically detected. When 279 real food samples were tested, the assay was highly consistent (100%) with culture-based methods. The results for 110 food samples artificially contaminated with single or multiple targets showed a high detection rate (≥ 80%) for most target bacteria. Overall, the TC-UPT-LF assay allows the rapid, quantitative, and simultaneous detection of 10 kinds of foodborne pathogens within 20 min, and is especially suitable for the rapid detection and surveillance of foodborne pathogens in food and water. PMID:26884128

  9. Performance capabilities of a space-power liquid metal MHD converter

    NASA Astrophysics Data System (ADS)

    Laborde, R.; Alemany, A.; Werkoff, F.

    In a Liquid Metal MHD (or Faraday) converter, thermal energy is converted into electrical energy by the expansion of a condensable fluid, the acceleration of a liquid metal and its circulation through a MHD generator. The performance capabilities of such a converter appear to be very attractive for a utilization in space with lithium and caesium as liquid metal and condensable fluid respectively. A code based on balance equations has been developed to estimate the masses, sizes and efficiencies of all parts of the converters. Iterative methods are used for each part, while the caesium mass flow rate acts as a control parameter in an external loop. Lastly we present results typical of a 200 kW electrical power station.

  10. Rotorcraft convertible engine study

    NASA Technical Reports Server (NTRS)

    Goldstein, D. N.; Hirschkron, R.; Smith, C. E.

    1983-01-01

    Convertible propulsion systems for advanced rotorcraft are evaluated in terms of their impact on aircraft operating economics and fuel consumption. A variety of propulsion system concepts, including separate thrust and power producing engines, convertible fan/shaft engines, and auxiliary propeller configurations are presented. The merits of each are evaluated in two different rotorcraft missions: an intercity, commercial transport of the ABC(TM) type, and an offshore oil ring supply ship of the X-wing type. The variable inlet guide vane fan/shaft converting engine and auxiliary propeller configurations are shown to offer significant advantages over all the other systems evaluated, in terms of both direct operating cost and fuel consumption.

  11. Vector generator scan converter

    DOEpatents

    Moore, J.M.; Leighton, J.F.

    1988-02-05

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardware for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold. 7 figs.

  12. Vector generator scan converter

    DOEpatents

    Moore, James M.; Leighton, James F.

    1990-01-01

    High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

  13. A Thermally-Regenerative Ammonia-Based Flow Battery for Electrical Energy Recovery from Waste Heat.

    PubMed

    Zhu, Xiuping; Rahimi, Mohammad; Gorski, Christopher A; Logan, Bruce

    2016-04-21

    Large amounts of low-grade waste heat (temperatures <130 °C) are released during many industrial, geothermal, and solar-based processes. Using thermally-regenerative ammonia solutions, low-grade thermal energy can be converted to electricity in battery systems. To improve reactor efficiency, a compact, ammonia-based flow battery (AFB) was developed and tested at different solution concentrations, flow rates, cell pairs, and circuit connections. The AFB achieved a maximum power density of 45 W m(-2) (15 kW m(-3) ) and an energy density of 1260 Wh manolyte (-3) , with a thermal energy efficiency of 0.7 % (5 % relative to the Carnot efficiency). The power and energy densities of the AFB were greater than those previously reported for thermoelectrochemical and salinity-gradient technologies, and the voltage or current could be increased using stacked cells. These results demonstrated that an ammonia-based flow battery is a promising technology to convert low-grade thermal energy to electricity. PMID:26990485

  14. Impact of ISWEC sea wave energy converter on posidonia oceanica meadows assessed by satellite remote sensing in the coastal areas of Pantelleria island

    NASA Astrophysics Data System (ADS)

    Borfecchia, Flavio; Micheli, Carla; Belmonte, Alessandro; De Cecco, Luigi; Sannino, Gianmaria; Bracco, Giovanni; Mattiazzo, Giuliana; Vittoria Struglia, Maria

    2016-04-01

    Marine renewable energy extraction plays a key role both in energy security of small islands and in mitigation of climate change, but at the same time poses the important question of monitoring the effects of the interaction of such devices with the marine environment. In this work we present a new methodology, integrating satellite remote sensing techniques with in situ observations and biophysical parameters analysis, for the monitoring and mapping of Posidonia Oceanica (PO) meadows in shallow coastal waters. This methodology has been applied to the coastal area offshore Pantelleria Island (Southern Mediterranean) where the first Italian Inertial Sea Wave Energy Converter (ISWEC) prototype has been recently installed. The prototype, developed by the Polytechnic of Turin consists of a platform 8 meters wide, 15 meters long and 4.5 meters high, moored at about 800 meters from the shore and at 31 m depth. It is characterized by high conversion efficiency, resulting from its adaptability to different wave conditions, and a limited environmental impact due to its mooring innovative method with absence of fixed anchors to the seabed. The island of Pantelleria, is characterized by high transparency of coastal waters and PO meadows ecosystems with still significant levels of biodiversity and specific adaptation to accentuated hydrodynamics of these shores. Although ISWEC is a low-impact mooring inertial system able to ensure a reliable connection to the electric grid with minimal impact on seagrass growing in the seabed, the prototype installation and operation involves an interaction with local PO and seagrass meadows and possible water transparency decreasing. In this view monitoring of local PO ecosystem is mandatory in order to allow the detection of potential stress and damages due to ISWEC related activities and/or other factors. However, monitoring and collection of accurate and repetitive information over large areas of the necessary parameters by means of

  15. Nonuniversality of entanglement convertibility

    NASA Astrophysics Data System (ADS)

    Bragança, Helena; Mascarenhas, Eduardo; Luiz, G. I.; Duarte, C.; Pereira, R. G.; Santos, M. F.; Aguiar, M. C. O.

    2014-06-01

    Recently, it has been suggested that operational properties connected to quantum computation can be alternative indicators of quantum phase transitions. In this work we systematically study these operational properties in one-dimensional systems that present phase transitions of different orders. For this purpose, we evaluate the local convertibility between bipartite ground states. Our results suggest that the operational properties, related to nonanalyticities of the entanglement spectrum, are good detectors of explicit symmetries of the model, but not necessarily of phase transitions. We also show that thermodynamically equivalent phases, such as Luttinger liquids, may display different convertibility properties depending on the underlying microscopic model.

  16. A solar thermophotovoltaic converter

    NASA Astrophysics Data System (ADS)

    Demichelis, F.; Minetti-Mezzetti, E.

    1980-08-01

    A model of a thermophotovoltaic (TPV) converter is presented. Sunlight was focused by an optical system into a spherical cavity made of tungsten or of ytterbium oxide, thereby heating the cavity. The spectral region of the incandescent radiation emitted by the cavity in the range 0.6-1.1 microns (corresponding to the maximum efficiency of silicon cells) was directed onto a distribution of cells facing the radiator. The part of the spectrum not in the range 0.6-1.1 microns was sent back to the radiator and recycled. Conversion efficiencies of about 24% are possible in a TPV converter operating with a 2000 K radiator.

  17. Photoelectric converters with quantum coherence.

    PubMed

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency η_{CA}. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to η_{CA} through manipulation of carefully controlled quantum coherences. PMID:27300826

  18. Photoelectric converters with quantum coherence

    NASA Astrophysics Data System (ADS)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency ηCA. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to ηCA through manipulation of carefully controlled quantum coherences.

  19. 100 gigasamples per second 12 bits optoelectronic analog-to-digital converter design and implementation based on cellular polyphase-sampling architecture

    NASA Astrophysics Data System (ADS)

    Villa-Angulo, Carlos

    The next generation digital information systems such as high performance computers, multigigabit/sec communication networks, distributed sensors, three dimensional digital imaging systems etc, will require analog-to-digital converters (ADCs) with high sampling rates exceeding 10 Gigasamples per second (GSPS) and high bit resolution of at least 10 bits. Such performance criteria are difficult to achieve with silicon electronics technology because the switching speeds peak at about 10-20GHz. Also, timing jitters, amplitude fluctuations, phase noise, thermal noise, and harmonic distortion, all contribute to reductions in ADC bit resolution as sampling rate increases. Photonics ADCs are rapidly emerging as the enabling technologies for high-performance digital signal processing systems. For this technology, high optical pulses repetition rate (in the order of GHz) with low time jitter and pulse width in the femtoseconds regime are the major attractive characteristics of optical sources. In this dissertation work, a novel 102.4 GSPS 12-bit optoelectronic analog-to-digital converter architecture that is based on a Cellular Polyphase-Sampling architecture is introduced. First, a 102.4 GHz all-optical clock was designed and implemented using a femtosecond laser source and passive optical components. Second, a novel optoelectronic architecture for optical sampling and parallel demultiplexing of different phases (polyphase) of an input analog signal is presented. The optoelectronic sampling and demultiplexing architecture is composed by 20 optoelectronic subcircuit referred as "OE-Cell"; these have been designed and implemented using optical passive components and InGaAs PIN photodiodes. A unique feature of this approach is that the optically sampled RF signal always remains in the electrical domain and thus eliminates the need for electrical-to-optical and optical-to-electrical conversions. The electrical-in to electrical-out transfer functions of the sampling and

  20. Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux

    NASA Astrophysics Data System (ADS)

    Nogrette, F.; Heurteau, D.; Chang, R.; Bouton, Q.; Westbrook, C. I.; Sellem, R.; Clément, D.

    2015-11-01

    We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 106 s-1 and three-dimensional reconstruction of the coordinates up to 3.2 × 106 particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 105 particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles.

  1. A 12-bit 3.7-Msample/s Pipelined A/D Converter Based on the Novel Capacitor Mismatch Calibration Technique

    NASA Astrophysics Data System (ADS)

    Wang, Shuaiqi; Li, Fule; Inoue, Yasuaki

    This paper proposes a 12-bit 3.7-MS/s pipelined A/D Converter based on the novel capacitor mismatch calibration technique. The conventional stage is improved to an algorithmic circuit involving charge summing, capacitors' exchange and charge redistribution, simply through introducing some extra switches into the analog circuit. This proposed ADC obtains the linearity beyond the accuracy of the capacitor match and verifies the validity of reducing the nonlinear error from the capacitor mismatch to the second order without additional power dissipation through the novel capacitor mismatch calibration technique. It is processed in 0.5μm CMOS technology. The transistor-level simulation results show that 72.6dB SNDR, 78.5dB SFDR are obtained for a 2V Vpp 159.144kHz sine input sampled at 3.7MS/s. The whole power dissipation of this ADC is 33.4mW at the power supply of 5V.

  2. New Cardiovascular and Pulmonary Therapeutic Strategies Based on the Angiotensin-Converting Enzyme 2/Angiotensin-(1–7)/Mas Receptor Axis

    PubMed Central

    Ferreira, Anderson J.; Murça, Tatiane M.; Fraga-Silva, Rodrigo A.; Castro, Carlos Henrique; Raizada, Mohan K.; Santos, Robson A. S.

    2012-01-01

    Angiotensin (Ang)-(1–7) is now recognized as a biologically active component of the renin-angiotensin system (RAS). The discovery of the angiotensin-converting enzyme homologue ACE2 revealed important metabolic pathways involved in the Ang-(1–7) synthesis. This enzyme can form Ang-(1–7) from Ang II or less efficiently through hydrolysis of Ang I to Ang-(1–9) with subsequent Ang-(1–7) formation. Additionally, it is well established that the G protein-coupled receptor Mas is a functional ligand site for Ang-(1–7). The axis formed by ACE2/Ang-(1–7)/Mas represents an endogenous counter regulatory pathway within the RAS whose actions are opposite to the vasoconstrictor/proliferative arm of the RAS constituted by ACE/Ang II/AT1 receptor. In this review we will discuss recent findings concerning the biological role of the ACE2/Ang-(1–7)/Mas arm in the cardiovascular and pulmonary system. Also, we will highlight the initiatives to develop potential therapeutic strategies based on this axis. PMID:22319643

  3. Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux.

    PubMed

    Nogrette, F; Heurteau, D; Chang, R; Bouton, Q; Westbrook, C I; Sellem, R; Clément, D

    2015-11-01

    We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 10(6) s(-1) and three-dimensional reconstruction of the coordinates up to 3.2 × 10(6) particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 10(5) particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles. PMID:26628119

  4. Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux

    SciTech Connect

    Nogrette, F.; Chang, R.; Bouton, Q.; Westbrook, C. I.; Clément, D.; Heurteau, D.; Sellem, R.

    2015-11-15

    We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 10{sup 6} s{sup −1} and three-dimensional reconstruction of the coordinates up to 3.2 × 10{sup 6} particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 10{sup 5} particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles.

  5. A PWM Buck Converter With Load-Adaptive Power Transistor Scaling Scheme Using Analog-Digital Hybrid Control for High Energy Efficiency in Implantable Biomedical Systems.

    PubMed

    Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik

    2015-12-01

    We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor. PMID:26742139

  6. DOE's energy data base (EDB) versus other energy-related data bases: a comparative analysis

    SciTech Connect

    Robinson, J.; Hu, M.

    1981-02-01

    The release of the DOE Energy Data Base to commercial services in 1980 raised an immediate question in the minds of some searchers: how does this new data base fit into the spectrum of already-available data bases. Because the authors have been closely associated with the Department of Energy's RECON system and its data bases for several years, as trainers and as editor of the DOE/RECON Newsletter, the question was of great interest and we decided to investigate it.

  7. Fractional Watt AMTEC Converter

    NASA Astrophysics Data System (ADS)

    Hunt, T. K.; Rasmussen, J. R.

    2006-01-01

    We report here the long term performance of a small, multi-tube AMTEC converter. This converter was designed to operate and produce approximately 12 watt of electrical output from a small, 4 to 6 watt radioisotope heat source for remote power applications. It was built and put on test in 1999 using electrical heaters as stand-ins for the radioisotope capsule. Since that time it has accumulated more than 5 years of run time at an input heater temperature of 700 °C, with numerous thermal cycles to ambient that were generally related to grid power failures or physical moves of the test apparatus. The power output has remained, with variations due to orientation changes and minor variations due to small temperature changes, essentially constant at 0.40 W to 0.60 W over the test period and operation is ongoing. The converter casing and mechanical structure was fabricated from 316 SS and the electrodes are sputtered titanium nitride films. Separate static tests of a multilayer insulation package suitable for use with the converter showed the capability to reach 700 °C with a thermal input of < 4 watts.

  8. High-sensitivity converters of a TV type

    NASA Astrophysics Data System (ADS)

    Venediktov, M. D.; Krutyakov, Yu. A.; Plotnikov, M. I.

    1999-06-01

    Three principles of building high sensitive (low-level) converters of a TV-type are well known. They are based on the following: (1) usage of electron-optical image converters (IC) as input image amplifiers and its converting into a TV signal by commercial TV cameras (Fig. 1a); (2) location in a single vacuum volume of a receiving input part of IC with a diode silicon substrate -- a storage target -- in which a photoelectric image is being amplified (amplification factor is 100 . . . 300) and then is read out by an electron beam with the energy corresponding with the condition (sigma) less than 1 ((sigma) -- secondary electron emission coefficient). The converter developed on the base of this principal has got the name of superkremnikon (a super silicon-imaging device) (Fig. 1b); (3) location in a single vacuum volume of a receiving part of IC, amplification microchannel plate (MCP) with amplification factor 100 . . . 1000 and a CCD with amplification equal to 100 (Fig. 1c). One should take into account the following disadvantages of the above-mentioned devices of a TV-type: (1) not high linear resolution of an input image, caused by multiple conversion of an input image - - (2.2 . . . 3.5)(DOT)102 lines in the middle of a target; (2) inadequately high sensitivity, defined basically by optical losses. Limiting sensitivity within the visible range has been realized at superkremnikon (10-7 lx) coupled with an input IC through fiber-optical communication; (4) high cost of the converters, which is limiting their wide practical application for the purposes of medical diagnostics and non- destructive control. The alternative principle of building the high sensitive converters of a TV-type, based on a new method of energy radiation image conversion within a wide spectral range into an electrical (including TV) signal is proposed. In the frames of the new method the MCP is operating at the same time as a receiver, an amplifier and a two-sided storage target on reading out

  9. BOARD-INVITED REVIEW: Efficiency of converting digestible energy to metabolizable energy and reevaluation of the California Net Energy System maintenance requirements and equations for predicting dietary net energy values for beef cattle.

    PubMed

    Galyean, M L; Cole, N A; Tedeschi, L O; Branine, M E

    2016-04-01

    For the past several decades, nutrient requirement systems for beef cattle in North America have recommended that dietary ME can be calculated as dietary DE × 0.82, but considerable published data suggest a variable relationship between DE and ME. We reviewed the literature and tabulated the results of 23 respiration calorimetry studies (87 treatment mean data points), in which measurements of fecal, urinary, and gaseous energy were determined with beef cattle (bulls, steers, and heifers) and growing dairy cattle. Mixed-model regression analyses to adjust for the effects of the citation from which the data were obtained suggested a strong linear relationship between ME and DE (Mcal/kg of DM; ME = 0.9611 × DE - 0.2999; = 0.986, root mean square error [RMSE] = 0.048, < 0.001 for intercept, slope ≠ 0). Analysis of residuals from this simple linear regression equation indicated high correlations of residuals with other dietary components, and a slight increase in precision was obtained when dietary CP, ether extract, and starch (% of DM) concentrations were included in a multiple linear regression equation (citation-adjusted = 0.992, RMSE = 0.039). Using the simple linear relationship, we reevaluated the original data used to develop the California Net Energy System (CNES) for beef cattle by recalculating ME intake and heat production and regressing the logarithm of heat production on ME intake (both per BW, kg daily). The resulting intercept and slope of the recalculated data did not differ ( ≥ 0.34) from those reported for the original analyses of the CNES data, suggesting that use of the linear equation for calculating ME concentration was consistent with NEm and NEg values as derived in the CNES. Nonetheless, because the cubic equations recommended by the NRC to calculate dietary NEm and NEg from ME were based on conversion of DE to ME using 0.82, these equations were mathematically recalculated to account for the linear relationship between DE and ME

  10. Design of a flexible component gathering algorithm for converting cell-based models to graph representations for use in evolutionary search

    PubMed Central

    2014-01-01

    Background The ability of science to produce experimental data has outpaced the ability to effectively visualize and integrate the data into a conceptual framework that can further higher order understanding. Multidimensional and shape-based observational data of regenerative biology presents a particularly daunting challenge in this regard. Large amounts of data are available in regenerative biology, but little progress has been made in understanding how organisms such as planaria robustly achieve and maintain body form. An example of this kind of data can be found in a new repository (PlanformDB) that encodes descriptions of planaria experiments and morphological outcomes using a graph formalism. Results We are developing a model discovery framework that uses a cell-based modeling platform combined with evolutionary search to automatically search for and identify plausible mechanisms for the biological behavior described in PlanformDB. To automate the evolutionary search we developed a way to compare the output of the modeling platform to the morphological descriptions stored in PlanformDB. We used a flexible connected component algorithm to create a graph representation of the virtual worm from the robust, cell-based simulation data. These graphs can then be validated and compared with target data from PlanformDB using the well-known graph-edit distance calculation, which provides a quantitative metric of similarity between graphs. The graph edit distance calculation was integrated into a fitness function that was able to guide automated searches for unbiased models of planarian regeneration. We present a cell-based model of planarian that can regenerate anatomical regions following bisection of the organism, and show that the automated model discovery framework is capable of searching for and finding models of planarian regeneration that match experimental data stored in PlanformDB. Conclusion The work presented here, including our algorithm for converting cell-based

  11. Nanotechnology for energy-based cancer therapies

    PubMed Central

    Gilstrap, Kyle; Hu, Xiaoxiao; Lu, Xiongbin; He, Xiaoming

    2011-01-01

    To overcome problems of systemic toxicity associated with chemotherapy and enhance treatment resolution of cancer therapies, nanotechnology is increasingly providing many novel approaches, especially to energy-based cancer therapies. Enhancements to treatment targeting, the ability to facilitate combined therapies, and treatment imaging are but a few of the ongoing investigations in this ever growing field. This review briefly explores the modalities of energy-based cancer therapies, how nanotechnology has been allowed for improvements within them, and discusses potential future applications of combined therapies. PMID:21984969

  12. Structure-based rational design of peptide hydroxamic acid inhibitors to target tumor necrosis factor-α converting enzyme as potential therapeutics for hepatitis.

    PubMed

    Wu, Dan; Gu, Qiuhong; Zhao, Ning; Xia, Fei; Li, Zhiwei

    2015-12-01

    The human tumor necrosis factor-α converting enzyme (TACE) has recently been raised as a new and promising therapeutic target of hepatitis and other inflammatory diseases. Here, we reported a successful application of the solved crystal structure of TACE complex with a peptide-like ligand INN for rational design of novel peptide hydroxamic acid inhibitors with high potency and selectivity to target and inhibit TACE. First, the intermolecular interactions between TACE catalytic domain and INN were characterized through an integrated bioinformatics approach, with which the key substructures of INN that dominate ligand binding were identified. Subsequently, the INN molecular structure was simplified to a chemical sketch of peptide hydroxamic acid compound, which can be regarded as a linear tripeptide capped by a N-terminal carboxybenzyl group (chemically protective group) and a C-terminal hydroxamate moiety (coordinated to the Zn(2+) at TACE active site). Based on the sketch, a virtual combinatorial library containing 180 peptide hydroxamic acids was generated, from which seven samples were identified as promising candidates by using a knowledge-based protein-peptide affinity predictor and were then tested in vitro with a standard TACE activity assay protocol. Consequently, three designed peptide hydroxamic acids, i.e. Cbz-Pro-Ile-Gln-hydroxamic acid, Cbz-Leu-Ile-Val-hydroxamic acid and Cbz-Phe-Val-Met-hydroxamic acid, exhibited moderate or high inhibitory activity against TACE, with inhibition constants Ki of 36 ± 5, 510 ± 46 and 320 ± 26 nM, respectively. We also examined the structural basis and non-bonded profile of TACE interaction with a designed peptide hydroxamic acid inhibitor, and found that the inhibitor ligand is tightly buried in the active pocket of TACE, forming a number of hydrogen bonds, hydrophobic forces and van der Waals contacts at the interaction interface, conferring both stability and specificity for TACE-inhibitor complex

  13. Volume of interest-based [18F]fluorodeoxyglucose PET discriminates MCI converting to Alzheimer's disease from healthy controls. A European Alzheimer's Disease Consortium (EADC) study.

    PubMed

    Pagani, M; De Carli, F; Morbelli, S; Öberg, J; Chincarini, A; Frisoni, G B; Galluzzi, S; Perneczky, R; Drzezga, A; van Berckel, B N M; Ossenkoppele, R; Didic, M; Guedj, E; Brugnolo, A; Picco, A; Arnaldi, D; Ferrara, M; Buschiazzo, A; Sambuceti, G; Nobili, F

    2015-01-01

    An emerging issue in neuroimaging is to assess the diagnostic reliability of PET and its application in clinical practice. We aimed at assessing the accuracy of brain FDG-PET in discriminating patients with MCI due to Alzheimer's disease and healthy controls. Sixty-two patients with amnestic MCI and 109 healthy subjects recruited in five centers of the European AD Consortium were enrolled. Group analysis was performed by SPM8 to confirm metabolic differences. Discriminant analyses were then carried out using the mean FDG uptake values normalized to the cerebellum computed in 45 anatomical volumes of interest (VOIs) in each hemisphere (90 VOIs) as defined in the Automated Anatomical Labeling (AAL) Atlas and on 12 meta-VOIs, bilaterally, obtained merging VOIs with similar anatomo-functional characteristics. Further, asymmetry indexes were calculated for both datasets. Accuracy of discrimination by a Support Vector Machine and the AAL VOIs was tested against a validated method (PALZ). At the voxel level SMP8 showed a relative hypometabolism in the bilateral precuneus, and posterior cingulate, temporo-parietal and frontal cortices. Discriminant analysis classified subjects with an accuracy ranging between .91 and .83 as a function of data organization. The best values were obtained from a subset of 6 meta-VOIs plus 6 asymmetry values reaching an area under the ROC curve of .947, significantly larger than the one obtained by the PALZ score. High accuracy in discriminating MCI converters from healthy controls was reached by a non-linear classifier based on SVM applied on predefined anatomo-functional regions and inter-hemispheric asymmetries. Data pre-processing was automated and simplified by an in-house created Matlab-based script encouraging its routine clinical use. Further validation toward nonconverter MCI patients with adequately long follow-up is needed. PMID:25610765

  14. Fast high-throughput screening of angiotensin-converting enzyme insertion/deletion polymorphism by variable programmed electric field strength-based microchip electrophoresis.

    PubMed

    Sun, Yucheng; Kim, Su-Kang; Zhang, Peng; Woo, Nain; Kang, Seong Ho

    2016-08-15

    An insertion (I)/deletion (D) polymorphism in angiotensin-converting enzyme (ACE) has been associated with susceptibility to various diseases in numerous studies. Traditionally, slab gel electrophoresis (SGE) after polymerase chain reaction (PCR) has been used to genotype this ACE I/D polymorphism. In this study, single- and multi-channel microchip electrophoresis (ME) methods based on variable programmed electric field strength (PEFS) (i.e., low constant, high constant, (+)/(-) staircase, and random electric field strengths) were developed for fast high-throughput screening of this specific polymorphism. The optimum PEFS conditions were set as 470V/cm for 0-9s, 129V/cm for 9-13s, 470V/cm for 13-13.9s, 294V/cm for 13.9-16s, and 470V/cm for 16-20s for single-channel ME, and 615V/cm for 0-22.5s, 231V/cm for 22.5-28.5s, and 615V/cm for 28.5-40s for multi-channel ME, respectively. In the multi-channel PEFS-ME, target ACE I/D polymorphism DNA fragments (D=190bp and I=490bp) were identified within 25s without loss of resolving power, which was ∼300 times faster than conventional SGE. In addition, PCR products of the ACE gene from human blood samples were detected after only 10 cycles by multi-channel PEFS-ME, but not by SGE. This parallel detection multichannel-based PEFS-ME method offers a powerful tool for fast high-throughput ACE I/D polymorphism screening with high sensitivity. PMID:27322633

  15. Phase transformation based pyroelectric waste heat energy harvesting with improved practicality

    NASA Astrophysics Data System (ADS)

    Ryul Jo, Hwan; Lynch, Christopher S.

    2016-03-01

    In 2014, almost 60% of thermal energy produced in the United States was lost to the environment as waste heat. Ferroelectric based pyroelectric devices can be used to convert some of this waste heat into usable electrical energy using the Olsen cycle, an ideal thermodynamic cycle, but there are a number of barriers to its realization in a practical device. This study uses the Olsen cycle to benchmark a less efficient thermodynamic cycle that is more easily implemented in devices. The ferroelectric pyroelectric material used was (Pb0.97La0.02)(Zr0.55Sn0.32Ti0.13)O3 ceramic, a ferroelectric material that undergoes a temperature driven phase transformation. A net energy density of 0.27 J cm-3 per cycle was obtained from the ferroelectric material using the modified cycle with a temperature change between 25°C and 180°C. This is 15.5% of the Olsen cycle result with the same temperature range and 1-8 MV m-1 applied electric field range. The power density was estimated to 13.5 mW cm-3 with given experimental conditions. A model is presented that quantitatively describes the effect of several parameters on output energy density and can be used to design ferroelectric based pyroelectric energy converters. The model indicates that optimization of material geometry and heating conditions can increase the output power by an order or magnitude.

  16. Optimized control of a flyback-converter for bidirectional feeding of DEAP transducers

    NASA Astrophysics Data System (ADS)

    Hoffstadt, Thorben; Maas, Jürgen

    2014-03-01

    Considering electromechanical transducers based on dielectric electroactive polymers (DEAP) beside a proper transducer design a feeding power supply is mandatory. In order to increase the energy efficiency these power electronics should provide a bidirectional energy flow. Therefore, in this contribution a bidirectional flyback-converter is investigated. Since the superimposed application-oriented control of the DEAP transducer requires an accurate control of the transducer voltage, in a first step a mathematical description of the flyback-converter for feeding capacitive loads is carried out. Based on this a sensor-based as well as a sensor-less current control is developed that is finally superimposed by a voltage control. The obtained results are experimentally validated by measurements of a realized prototype of the bidirectional flyback-converter feeding a DEAP transducer.

  17. Evaluation of Up-Converting Phosphor Technology-Based Lateral Flow Strips for Rapid Detection of Bacillus anthracis Spore, Brucella spp., and Yersinia pestis

    PubMed Central

    Zhao, Yong; Hua, Fei; Li, Chunfeng; Yang, Ruifu; Zhou, Lei

    2014-01-01

    Bacillus anthracis, Brucella spp., and Yersinia pestis are zoonotic pathogens and biowarfare- or bioterrorism-associated agents that must be detected rapidly on-site from various samples (e.g., viscera and powders). An up-converting phosphor technology-based lateral flow (UPT–LF) strip was developed as a point-of-care testing (POCT) to satisfy the requirements of first-level emergency response. We developed UPT–LF POCT to quantitatively detect the three pathogens within 15 min. Sample and operation-error tolerances of the assay were comprehensively evaluated. The sensitivity of UPT–LF assay to bacterial detection reached 104 cfu·mL−1 (100 cfu/test), with a linear quantitative range of 4 to 6 orders of magnitude. Results revealed that the UPT–LF assay exhibited a high specificity with the absence of false-positive results even at 109 cfu·mL−1 of non-specific bacterial contamination. The assay could tolerate samples with a wide pH range (2 to 12), high ion strengths (≥4 mol·L−1 of NaCl), high viscosities (≤25 mg·mL−1 of PEG20000 or ≥20% of glycerol), and high concentrations of bio-macromolecule (≤200 mg·mL−1 of bovine serum albumin or ≥80 mg·mL−1 of casein). The influence of various types of powders and viscera (fresh and decomposed) on the performance of UPT–LF assay was determined. The operational error of liquid measurement exhibited few effects on sensitivity and specificity. The developed UPT–LF POCT assay is applicable under field conditions with excellent tolerance to sample complexity and operational error. PMID:25144726

  18. ANALOG-TO-DIGITAL DATA CONVERTER

    DOEpatents

    Rodgers, G.W.; Althouse, J.E.; Anderson, D.P.; Bussey, G.R.; Minnear, L.H.

    1960-09-01

    Electrical apparatus is described, particularly useful in telemetry work, for converting analog signals into electrical pulses and recording them. An electronic editor commands the taking of signal readings at a frequency which varies according to linearity of the analog signal being converted. Readings of information signals are recorded, along with time base readings and serial numbering, if desired, on magnetic tape and the latter may be used to operate a computer or the like. Magnetic tape data may be transferred to punched cards.

  19. Digital to synchro converter

    NASA Technical Reports Server (NTRS)

    Predina, Joseph P. (Inventor)

    1989-01-01

    A digital-to-synchro converter is provided where a binary input code specifies a desired shaft angle and where an resolver type position transducer is employed with additional circuitry to generate a shaft position error signal indicative of the angular difference between the desired shaft angle and the actual shaft angle. The additional circuitry corrects for known and calculated errors in the shaft position detection process and equipment.

  20. A cm scale electret-based electrostatic wind turbine for low-speed energy harvesting applications

    NASA Astrophysics Data System (ADS)

    Perez, M.; Boisseau, S.; Gasnier, P.; Willemin, J.; Geisler, M.; Reboud, J. L.

    2016-04-01

    This paper presents a small-scale airflow energy harvester built on an axial turbine architecture and exploiting an electret-based electrostatic converter. When the airflow velocity is high enough, the windmill starts rotating and creates a periodic relative motion between a stator and a rotor which induces variations of capacitance. These ones are directly converted into electricity thanks to the use of Teflon electrets charged at -1400 V which polarize the variable capacitors. We focus our study on a 4-blade axial turbine with a diameter of D = 40 mm, a depth of W = 10 mm, for a total volume of 12.6 cm3. This windmill has been tested with various blade angles and different types of electrostatic converters and output powers up to 90 μW at 1.5 m s-1 (7.5 μW cm-3) and 1.8 mW at 10 m s-1 (111 μW cm-3) have been obtained so far. The coefficient of power reaches C p = 5.8% and among the small-scale airflow energy harvesters previously reported, this one has the lowest cut-in speed (1.5 m s-1).

  1. Changes in soil organic carbon and total nitrogen in croplands converted to walnut-based agroforestry systems and orchards in southeastern Loess Plateau of China.

    PubMed

    Lu, Sen; Meng, Ping; Zhang, Jinsong; Yin, Changjun; Sun, Shiyou

    2015-11-01

    Limited information is available on the effects of agroforestry system practices on soil properties in the Loess Plateau of China. Over the last decade, a vegetation restoration project has been conducted in this area by converting cropland into tree-based agroforestry systems and orchards to combat soil erosion and degradation. The objective of the present study was to determine the effects of land use conversion on soil organic carbon and total nitrogen in southeastern Loess Plateau. The experiment included three treatments: walnut intercropping system (AF), walnut orchard (WO), and traditional cropland (CR). After 7 years of continual management, soil samples were collected at 0-10, 10-30, and 30-50-cm depths for three treatments, and soil organic carbon (SOC) and total nitrogen (TN) were measured. Results showed that compared with the CR and AF treatments, WO treatment decreased both SOC and TN concentrations in the 0-50-cm soil profile. However, similar patterns of SOC and TN concentrations were observed in the AF and CR treatments across the entire profile. The SOC stocks at 0-50-cm depth were 5.42, 5.52, and 4.67 kg m(-2) for CR, AF, and WO treatments, respectively. The calculated TN stocks at 0-50-cm depth were 0.63, 0.62, and 0.57 kg m(-2) for CR, AF, and WO treatments, respectively. This result demonstrated that the stocks of SOC and TN in WO were clearly lower than those of AF and CR and that the walnut-based agroforestry system was more beneficial than walnut monoculture in terms of SOC and TN sequestration. Owing to the short-term intercropping practice, the changes in SOC and TN stocks were slight in AF compared with those in CR. However, a significant decrease in SOC and TN stocks was observed during the conversion of cropland to walnut orchard after 7 years of management. We also found that land use types had no significant effect on soil C/N ratio. These findings demonstrated that intercropping between walnut rows can potentially maintain

  2. Energy harvesting from stray power-frequency magnetic field employing a piezoelectric unimorph based heterostructure

    NASA Astrophysics Data System (ADS)

    He, Wei; Lu, Yueran; Zhang, Jitao; Qu, Chiwen; Che, Gaofeng; Peng, Jiancai

    2016-03-01

    An energy harvester using a piezoelectric unimorph based heterostructure is presented to convert stray power-frequency (50 Hz or 60 Hz) magnetic field energy into electrical energy. The harvester consists a piezoelectric unimorph and a U-shaped mass structure. The U-shaped mass structure with two parallel bar magnets leads to a large rotary inertia for the given proof mass. An enhanced exciting torque is induced on the unimorph and the response of the harvester to the external magnetic field is strengthened. Under the resonant frequency of 50 Hz, the harvester produces a power of 154.6 µW with a matching load resistance of 199 kΩ at a magnetic field of 0.5 Oe. Through an up-conversion management circuit, the energy harvester can successfully drive a wireless sensor node with high power consumption (90 mW at transmitting and 18 mW at receiving) at a duration of 205 ms.

  3. Piezoelectric-based energy-harvesting power sources for gun-fired munitions

    NASA Astrophysics Data System (ADS)

    Rastegar, J.; Haarhoff, D.; Pereira, C.; Nguyen, H.-L.

    2006-03-01

    This paper presents a new class of piezoelectric based energy harvesting power sources for use in gun-fired munitions or other similar applications requiring high G survivability . These power sources are designed to harvest energy from the firing acceleration as well as vibratory motion and spinning of munitions during their flight and convert it to electrical energy that could be used directly by power consuming electronics onboard munitions or stored. The power sources are designed to withstand firing accelerations in excess of 100,000 G. The power sources have been shown to have the potential of completely eliminating the need for chemical batteries in many fuzing applications, while having the added advantage of providing for considerably more safety and long shelf life. Prototypes of a number of designs of this class of energy harvesting power sources for various power requirements have been constructed and successfully tested in the laboratory and by the U. S. Army (ARDEC) using air guns.

  4. A low-voltage boost converter using a forward converter with integrated Meissner oscillator

    NASA Astrophysics Data System (ADS)

    Woias, P.; Islam, M.; Heller, S.; Roth, R.

    2013-12-01

    This paper describes a novel boost converter to be used with energy harvesters that provide only low output voltages. The device is self-supplied from electric power delivered to its input. With peak power conversion efficiencies above 30% at start-up voltages down to 10 mV this circuit sets best values in comparison with the state-of-the-art. This is achieved by the novel combination of a Meissner oscillator, used as stand-alone in most low-voltage step-up converters today, with a forward converter usually applied in high power systems.

  5. On lossless switched-capacitor power converters

    SciTech Connect

    Tse, C.K.; Wong, S.C.; Chow, M.H.L.

    1995-05-01

    This paper addresses the design of efficient switched-capacitor power converters. The discussion starts with a review of the fundamental limitation of switched-capacitor circuits which shows that the topology of such circuits and the ``forced`` step changes of capacitor voltages are the inherent attributes of power loss. Although the argument follows from a rather trivial result from basic circuit theory, it addresses an important issue on the maximum efficiency achievable in a switched-capacitor converter circuit. Based on the observed topological constraint of switched-capacitor converter circuits, the simplest lossless topology for AC/DC conversion is deduced. Also discussed is a simple version of lossless topology that achieves isolation between the source and the load. Finally, an experimental AC/DC switched-capacitor converter, based on the proposed idea, is presented which demonstrates an improved efficiency over other existing switched-capacitor converters. The proposed AC/DC converter contains no inductors and thus is suitable for custom IC implementation for very low power applications.

  6. Hybrid thermionic-photovoltaic converter

    NASA Astrophysics Data System (ADS)

    Datas, A.

    2016-04-01

    A conceptual device for the direct conversion of heat into electricity is presented. This concept hybridizes thermionic (TI) and thermophotovoltaic (TPV) energy conversion in a single thermionic-photovoltaic (TIPV) solid-state device. This device transforms into electricity both the electron and photon fluxes emitted by an incandescent surface. This letter presents an idealized analysis of this device in order to determine its theoretical potential. According to this analysis, the key advantage of this converter, with respect to either TPV or TI, is the higher power density in an extended temperature range. For low temperatures, TIPV performs like TPV due to the negligible electron flux. On the contrary, for high temperatures, TIPV performs like TI due to the great enhancement of the electron flux, which overshadows the photon flux contribution. At the intermediate temperatures, ˜1650 K in the case of this particular study, I show that the power density potential of TIPV converter is twice as great as that of TPV and TI. The greatest impact concerns applications in which the temperature varies in a relatively wide range, for which averaged power density enhancement above 500% is attainable.

  7. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2002-01-09

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant considered for similar concepts in the past. This document reports on the progress made in the program during the past quarter. It reports on projectile development experiments and the development of the electric launch system design.

  8. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2002-10-12

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant investigated for similar concepts in the past. This document reports on the progress made in the program during the past quarter. It reports on projectile development and the development of the electric launch system design.

  9. Transistorized converter provides nondissipative regulation

    NASA Technical Reports Server (NTRS)

    1964-01-01

    A transistorized regulator converter efficiently converts fluctuating input voltages to a constant output voltage, avoiding the use of saturable reactors. It is nondissipative in operation and functions in an open loop through variable duty cycles.

  10. Ferrofluid based micro-electrical energy harvesting

    NASA Astrophysics Data System (ADS)

    Purohit, Viswas; Mazumder, Baishakhi; Jena, Grishma; Mishra, Madhusha; Materials Department, University of California, Santa Barbara, CA93106 Collaboration

    2013-03-01

    Innovations in energy harvesting have seen a quantum leap in the last decade. With the introduction of low energy devices in the market, micro energy harvesting units are being explored with much vigor. One of the recent areas of micro energy scavenging is the exploitation of existing vibrational energy and the use of various mechanical motions for the same, useful for low power consumption devices. Ferrofluids are liquids containing magnetic materials having nano-scale permanent magnetic dipoles. The present work explores the possibility of the use of this property for generation of electricity. Since the power generation is through a liquid material, it can take any shape as well as response to small acceleration levels. In this work, an electromagnet-based micropower generator is proposed to utilize the sloshing of the ferrofluid within a controlled chamber which moves to different low frequencies. As compared to permanent magnet units researched previously, ferrofluids can be placed in the smallest of containers of different shapes, thereby giving an output in response to the slightest change in motion. Mechanical motion from 1- 20 Hz was able to give an output voltage in mV's. In this paper, the efficiency and feasibility of such a system is demonstrated.

  11. Electrothermodynamic (etd) power converter

    SciTech Connect

    Marks, A.M.

    1983-07-26

    These inventions relate to novel advances in Electrothermodynamics (ETD), also known as charged aerosol, heat/electric power generators: (1) A new more efficient, compact converging/diverging configuration comprising a torus of revolution (TORON) used with a gas flywheel. (2) A ''Method II'' two-fluid mixed flow ejector/converter in a gas flywheel loop employing a primary steam or a high molecular weight driver jet such as a fluorocarbon containing charged aerosol water droplets and a low molecular weight carrier gas such as hydrogen or helium with an electro-negative gas additive, in a Rankine cycle including a vapor/gas and liquid separator with a bypass to the ejector/converter loop. (3) A ''Method III'' two-fluid mixed flow comprising a supersonic jet expanding conically within a subsonic flow, separated by a boundary layer in which the charged aerosol forms downstream of the orifice, at a cross section of at least 100 times the orifice section; and in which the electric charge density of the charged aerosol decreases along the jet axis, whereby substantially all of the kinetic power of the jet is converted to electric power within the jet, there being no ejector. (4) An array of supersonic jets utilizing Method III. (5) An array of supersonic jets utilizing Method III without separating duct walls in which ''convection cells'' provide return flows, forming a plurality of TORON configurations. (6) A supercritical Rankline cycle in a single stage employing Method III. (7) A method IV two-fluid cycle uses charged aerosols in an inert gas and operates on an Ericsson-type cycle. (8) Optimum operating conditions are defined for Methods II, III, and IV. (9) A high potential emitter is employed with a grounded body, and a sapphire tube sealed to metal by a new technique provides an insulating duct for the high temperature, high pressure vapor.

  12. Potential converter for laser-power beaming

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Williams, Michael D.; Schuster, Gregory L.; Iles, Peter A.

    1991-01-01

    Future space missions, such as those associated with the Space Exploration Initiative (SEI), will require large amounts of power for operation of bases, rovers, and orbit transfer vehicles. One method for supplying this power is to beam power from a spaced based or Earth based laser power station to a receiver where laser photons can be converted to electricity. Previous research has described such laser power stations orbiting the Moon and beaming power to a receiver on the surface of the Moon by using arrays of diode lasers. Photovoltaic converters that can be efficiently used with these diode lasers are described.

  13. Bidirectional buck boost converter

    DOEpatents

    Esser, Albert Andreas Maria

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero.

  14. Bidirectional buck boost converter

    DOEpatents

    Esser, A.A.M.

    1998-03-31

    A bidirectional buck boost converter and method of operating the same allows regulation of power flow between first and second voltage sources in which the voltage level at each source is subject to change and power flow is independent of relative voltage levels. In one embodiment, the converter is designed for hard switching while another embodiment implements soft switching of the switching devices. In both embodiments, first and second switching devices are serially coupled between a relatively positive terminal and a relatively negative terminal of a first voltage source with third and fourth switching devices serially coupled between a relatively positive terminal and a relatively negative terminal of a second voltage source. A free-wheeling diode is coupled, respectively, in parallel opposition with respective ones of the switching devices. An inductor is coupled between a junction of the first and second switching devices and a junction of the third and fourth switching devices. Gating pulses supplied by a gating circuit selectively enable operation of the switching devices for transferring power between the voltage sources. In the second embodiment, each switching device is shunted by a capacitor and the switching devices are operated when voltage across the device is substantially zero. 20 figs.

  15. Efficient, lightweight dc/dc switching converter

    NASA Technical Reports Server (NTRS)

    Cuk, S.; Middlebrook, R. D.

    1981-01-01

    Converters have input properties of boost power stage and output properties of buck power stage, yet they perform general conversion function with high efficiency. Other features include non-pulsating input/output currents, use of capacitive energy transfer, low output voltage ripple, reduced EMI, and small size.

  16. Convert natural gas into clean transportation fuels

    SciTech Connect

    Agee, M.A.

    1997-03-01

    A new process economically converts natural gas into synthetic transportation fuels that are free of sulfur, metals, aromatics and are clear in appearance. The process, developed by Syntroleum Corp., is energy self-sufficient and can be implemented in sizes small enough to fit a large number of the world`s gas fields. The process is described.

  17. Observer-based higher order sliding mode control of power factor in three-phase AC/DC converter for hybrid electric vehicle applications

    NASA Astrophysics Data System (ADS)

    Liu, Jianxing; Laghrouche, Salah; Wack, Maxime

    2014-06-01

    In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.

  18. Dual energy converting nano-phosphors: upconversion luminescence and X-ray excited scintillation from a single composition of lanthanide-doped yttrium oxide.

    PubMed

    Stanton, Ian N; Ayres, Jennifer A; Therien, Michael J

    2012-10-14

    We report an upconverting nanomaterial composition, [Y(2)O(3); Yb (2%), Er (1%)], that converts both X-ray and high-fluence NIR irradiation to visible light. This composition is compared to a higher Yb(3+) doped composition, [Y(2)O(3); Yb (10%), Er (1%)], that displays diminished visible X-ray scintillation, but shows enhanced red wavelength centered upconversion emission. These nanocrystals have been characterized by TEM, X-ray diffraction, power-dependent upconversion luminescence, and X-ray scintillation spectroscopy. We further demonstrate that lithium ion doping of the [Y(2)O(3); Yb (2%), Er (1%)] nanoscale composition leads to enhanced X-ray and NIR excited emission intensities through the production of nanoparticles that feature slightly enhanced sizes and increased crystallinity. PMID:22940914

  19. Integrated Solar Power Converters: Wafer-Level Sub-Module Integrated DC/DC Converter

    SciTech Connect

    2012-02-09

    Solar ADEPT Project: CU-Boulder is developing advanced power conversion components that can be integrated into individual solar panels to improve energy yields. The solar energy that is absorbed and collected by a solar panel is converted into useable energy for the grid through an electronic component called an inverter. Many large, conventional solar energy systems use one, central inverter to convert energy. CU-Boulder is integrating smaller, microinverters into individual solar panels to improve the efficiency of energy collection. The University’s microinverters rely on electrical components that direct energy at high speeds and ensure that minimal energy is lost during the conversion process—improving the overall efficiency of the power conversion process. CU-Boulder is designing its power conversion devices for use on any type of solar panel.

  20. Measurements of plasma parameters in a simulated thermionic converter

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1971-01-01

    Cesium-filled thermionic energy converters are examined as candidate electrical energy sources in spacecraft requiring tens to hundreds of kilowatts of electric power. The high operating temperatures necessary for a large specific power and high efficiency inevitably impose stringent constraints on the converter fabrication to achieve the desired reliability of the power system. The converter physics for reducing operating temperatures and cesium plasma losses are studied to achieve high reliability without sacrificing the power performance of the converters. Various cesium parameters which affect the converter performance are: (1) electron temperatures, (2) plasma ion densities, and (3) electric potential profiles. These were investigated using a Langmuir probe in a simulated converter. The parameters were measured in different cesium discharge modes.