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Maximum Output Power (maximum + output_power)
Selected AbstractsProposal and development of radial air-gap coreless generator suitable for small wind turbine used in urban areaELECTRICAL ENGINEERING IN JAPAN, Issue 1 2009Toshiyuki Takahashi Abstract Independent distributed power generation using small wind turbines is becoming more widespread as wind power generation increases. Installation of small wind turbines in densely populated urban areas is not only useful from the viewpoint of extracting wind power sources in weak-wind areas but also for making renewable energy easier to access when power supplies are closer to consumers. It is from this point of view that the authors proposed "urban wind power generation" using a collective system with a number of small vertical wind turbines, and have developed a suitable generator for low-speed vertical wind turbines such as a Savonius windmill. Based on a standard coreless generator, the proposed generator is designed to make the direction of the magnetic flux radial in order to install the magnets and coils on the outer end of the generator. The change of magnet composition and flux direction maximizes the speed of the flux change and output voltage within a limited space. With the above configuration, the power of the proposed generator is independent of the diameter. In this report, the authors describe and evaluate the fundamental performance of a prototype of the proposed generator. Based on the experiments, a maximum output power of 283 W was obtained. The obtained starting torque is small enough to begin rotation under weak wind conditions of no more than 1 m/s. Therefore, it is clear that the proposed "radial" coreless generator is suitable for self-starting and producing high power at low wind speed. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 26, 34, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20695 [source] On mass transport in an air-breathing DMFC stackINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2005G. Q. Lu Abstract An 8-cell air-breathing direct methanol fuel cell (DMFC) stack with the active area of 5 cm2 of each cell has been developed. Stainless steel plates of 500 µm thickness with flow channels were fabricated using photochemical etching method as the current collectors. Different conditioning methods for membrane electrode assembly (MEA) activation were discussed. With proper control of water crossover to the cathode, cathode flooding was avoided in the DMFC stack. Methanol crossover at open circuit voltage (OCV) in the air-breathing DMFC was measured. Further, it was found that flow maldistribution might occur in the parallel flow field of the stack, making carbon dioxide gas management at the anode necessary. Using humidified hydrogen in the anode with a high flow rate, the oxygen transport limiting current density was characterized and found to be sufficient in the air-breathing cathode. The stack produced a maximum output power of 1.33 W at 2.21 V at room temperature, corresponding to a power density of 33.3 mW cm,2. Copyright © 2005 John Wiley & Sons, Ltd. [source] 8.5 W room temperature continuous wave operation of a Ho:LuAG laserLASER PHYSICS LETTERS, Issue 12 2009X.M. Duan Abstract We report the continuous wave Ho:LuAG laser operated at room temperature. Using the diode-pumped Tm:YLF laser as a pumping source, maximum output power of 8.5 W at 2100 nm was obtained under the incident pump power of 18.4 W, corresponding to a slope efficiency of 51.3% and a conversion efficiency of 46.2%. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Edge-pumped asymmetric Yb:YAG/YAG thin disk laserLASER PHYSICS LETTERS, Issue 10 2007Q. Liu Abstract An edge-pumping scheme for a quasi-three-level solid-state laser using asymmetric crystal is reported. The scheme uses a thin disk laser configuration with the pump light incident from disk edges. The pump light propagates through the disk along the zigzag path and repeatedly passes the gain medium, thus improving the pump uniformity and absorption efficiency. A maximum output power of over 123 W was achieved from an edge-pumped composite Yb:YAG/YAG thin disk laser, with slope efficiency of 34.8% and beam quality M2 , 20. (© 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Application of a rat-race coupler in low-cost load and source pull transistor amplifier designMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009Slawomir Gruszczy Abstract A method for load and source pull is proposed in which rat-race couplers with sections of shorted transmission lines are used. It is shown that the connection of a rat-race coupler with two shorted transmission lines allows for realization of any desired impedance, thus, allowing for effective transistor matching and, therefore, achieving maximum output power. Both theoretical analysis and experimental results are presented showing usefulness of the proposed technique. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2537,2541, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24668 [source] MMIC PAM applied with pre-distorter having independent operation of nonlinear signalMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2008Inn-Yeal Oh Abstract A dynamic pre-distorter with two paths to set nonlinear signal level and phase encourages power amplifier module (PAM) for wireless broadband (Wibro) service to enhance linearity. We proposed a linearizer having a new IM generator, which is made up of the InGaP/GaAs HBT operated at saturation region of a common collector circuit. The targeted Wibro PAM is designed using InGaP/GaAs HBT technology, and the pre-distorter, drive and power amplifier are fully integrated in single chip within 960 × 2400 ,m. Even though PAM is designed to have just a 5-dB back-off, PAM is compatible with linearity standards up to maximum output power 21 dBm, and has a 17.5% efficiency by having a low leakage and improving spurious of 6 dB in the 64QAM form based on IEEE802.16e-2005 standards. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 851,855, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23235 [source] Fiber-optic displacement sensor using a multimode bundle fiberMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2008Moh. Yasin Abstract A simple fiber optic displacement sensor based on intensity modulation technique is demonstrated using a bundle multimode plastic fiber as a probe. The sensor consists of a light source, a probe, and photodiode detector. The sensor is capable of measuring displacements of mirror ranging from 0.05 to 2.2 mm using a red light source of wavelength 632.8 nm with maximum output power of 1 mW. The sensitivity of the device is found to be 168.8 mV/mm over 0.05,0.35 mm range and ,29.8 mV/mm over 1.05,2.2 mm range. The sensor is highly sensitive at the front slope and very useful for close distance target. The simplicity of the design, high degree of sensitivity, dynamic range and the low cost of the fabrication make it suitable for applications in industries as position control and micro displacement measurement in the hazardous region. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 661,663, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23147 [source] High-power narrow line width tunable cladding pumped Er:Yb co-doped fiber laserMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2006Shu-min Zhang Abstract A narrow line width, tunable, and highly efficient fiber laser based on Er3+/Yb3+ co-doped double-clad fiber with the maximum output power of 438 mW and a slope efficiency of ,16% has been demonstrated. By using a fiber Bragg grating (FBG) as a narrow band reflector, 3-dB line width of the output laser could be as narrow as 0.04 nm over the whole tuning range, and by compressing or stretching the FBG, wavelength tunable range of 4.0 nm was realized. In the experiment, we also found that there existed an optimum splitting ratio of the output coupler, at which the maximum output power could reach ,647 mW. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1736,1739, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21762 [source] Remarkable improvement in output power for an InAlGaN based ultraviolet LED by improving the crystalline quality of AlN/AlGaN templatesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008T. Takano Abstract The use of quaternary InAlGaN is very attractive for the realization of commercially-available low-cost and high-power ultraviolet light-emitting diodes (UV-LEDs), because highly-efficient UV emission can be obtained from this material due to In-segregation effects. We achieved remarkable improvements in output power from 340 nm-band quaternary InAlGaN-based UV-LEDs and demonstrated high UV-output power by using high-quality AlN buffer templates on sapphire substrates. Threading dislocation densities (TDDs) for screw and edge-type dislocations were 1×108cm,2 and 1×109cm,2, as observed from cross-sectional transmission electron microscope (TEM) images. The output power of a 340 nm-band UV-LED was increased by approximately 7 times by reducing the full-width-at-half-maximum (FWHM) of the (10-12) X-ray ,-scan rocking curve (XRC) from around 800 arcsec to 510 arcsec. As a result, we achieved a maximum output power of 7.1 mW under room-temperature (RT) and continuous-wave (CW) operation. From these results, we confirmed that the crystalline quality of AlN/AlGaN templates strongly affects the output power of UV-LEDs. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Overcoming Kinetic Limitations of Electron Injection in the Dye Solar Cell via Coadsorption and FRETCHEMPHYSCHEM, Issue 5 2008Conrad Siegers Abstract A new, extremely simple concept for the use of energy transfer as a means to the enhancement of light absorption and current generation in the dye solar cell (DSC) is presented. This model study is based upon a carboxy-functionalized 4-aminonaphthalimide dye (carboxy-fluorol) as donor, and (NBu4)2[Ru(dcbpy)2(NCS)2] (N719) as acceptor chromophores. A set of three different devices is assembled containing either exclusively carboxy-fluorol or N719, or a mixture of both. This set of transparent devices is characterized via IV-measurements under AM1.5G and monochromatic illumination and their light-harvesting and external quantum efficiencies (LHE and EQE, respectively) are determined as well. It is shown that the device containing only the donor chromophore has a marginal power conversion efficiency, thus indicating that carboxy-fluorol is a poor sensitizer for the DSC. Cyclovoltametric measurements show that the poor sensitization ability arises from the kinetic inhibition of electron injection into the TiO2 conduction band. Comparing the spectral properties of the DSCs assembled presently, however, demonstrates that light absorbed by carboxy-fluorol is almost quantitatively contributing to the photocurrent if N719 is present as an additional sensitizer. In this case, N719 acts as a catalyst for the sensitization of TiO2 by carboxy-fluorol in addition to being a photosensitizer. Evaluation of the maximum output power under blue illumination shows that the introduction of an energy-donor moiety via coadsorption, leads to a significant increase in the monochromatic maximum output power. This result demonstrates that energy transfer between coadsorbed chromophores could be useful for the generation of current in dye-sensitized solar cells. [source] | |||||||||||||