Search Results 1-20 of 267

  • RANS and LES Simulations at Partial Load in Francis Turbines: Three Dimensional Topology and Dynamic Behaviour of Inter Blade Vortices

    Doussot F , Balarac G , Brammer J , Laurant Y , Métais O

    … However, to respond to the increasing demand for flexibility mainly due to the integration of renewable energy in the electric grid, the operating range of Francis turbines has to be extended towards smaller discharge levels without restriction. … When Francis turbines are operated typically between 30% and 60% of the rated output power, the flow field is characterized by the appearance of inter blade vortices in the runner. …

    International Journal of Fluid Machinery and Systems 13(1), 12-20, 2020

    J-STAGE 

  • Non-Equilibrium Quantum Brain Dynamics: Super-Radiance and Equilibration in 2+1 Dimensions

    Nishiyama Akihiro , Tanaka Shigenori , Tuszynski Jack A.

    … We derive time evolution equations, namely the Schrodinger-like equations and the Klein-Gordon equations for coherent fields and the Kadanoff-Baym (KB) equations for quantum fluctuations, in quantum electrodynamics (QED) with electric dipoles in 2 + 1 dimensions. … Our analysis can be applied to quantum brain dynamics, that is QED, with water electric dipoles. …

    Entropy 21(11), 1066, 2019-11

    IR 

  • Verification of Co-Generation Gas Engine Control Law by Combination of Model Matching and Optimal Observer (Third Report):-Verification of improved input disturbance model for fuel concentration fluctuation-  [in Japanese]

    Tanaka Yuya , Okamura Koichi , Kishi Ryota , Sumiya Yusuke , Takahata Kenji , Yang Jianming

    … There are few researches to respond to fluctuations in concentration of bio-methane fuel and load fluctuation of a generator using a co-generation gas engine generator of approximately 1kW. … The GET system is a bio-methane gas production paddy field of sustainable resource recycling type, and does not special auxiliary facilities. …

    Transactions of Society of Automotive Engineers of Japan 50(5), 1452-1457, 2019

    J-STAGE 

  • Intermittent Magnetic Fluctuations Associated with High-Temperature Bubbles in an ECR Plasma

    YOSHIMURA Shinji , TERASAKA Kenichiro , TANAKA Masayoshi Y.

    … It is found that the high-temperature bubble is accompanied by a pulsed magnetic fluctuation perpendicular to the external magnetic field. … Polarities of the magnetic fluctuation suggest that it should be induced by a transient upstream electric current. … The result suggests that the electron velocity distribution function in the bubble should be an asymmetric one, which gives rise to an effective upstream electric current.</p> …

    Plasma and Fusion Research 14(0), 3401081-3401081, 2019

    J-STAGE 

  • Substorm-Associated Ionospheric Flow Fluctuations During the 27 March 2017 Magnetic Storm: SuperDARN-Arase Conjunction

    Hori T. , Nishitani N. , Shepherd S. G. , Ruohoniemi J. M. , Connors M. , Teramoto M. , Nakano S. , Seki K. , Takahashi N. , Kasahara S. , Yokota S. , Mitani T. , Takashima T. , Higashio N. , Matsuoka A. , Asamura K. , Kazama Y. , Wang S.-Y. , Tam S. W. Y. , Chang T.-F. , Wang B.-J. , Miyoshi Y. , Shinohara I.

    … Super Dual Auroral Radar Network (SuperDARN) observations show that ionospheric flow fluctuations of millihertz or lower‐frequency range with horizontal velocities of a few hundred meters per second appeared in the subauroral to midlatitude region during a magnetic storm on 27 March 2017. … A set of the radars have provided the first ever observations that the fluctuations propagate azimuthally both westward and eastward simultaneously, showing bifurcated phase propagation associated with substorm expansion. …

    Geophysical Research Letters 45(18), 9441-9449, 2018-09-28

    IR 

  • Erratum: "Direct evidence of photoluminescence broadening enhancement by local electric field fluctuations in polar InGaN/GaN quantum wells"

    Baranowski Michał , Janicki Łukasz , Gladysiewicz Marta , Welna Monika , Latkowska Magdalena , Misiewicz Jan , Marona Łucja , Schiavon Dario , Perlin Piotr , Kudrawiec Robert

    Japanese Journal of Applied Physics 57(9), 099208-099208, 2018-08-22

    DOI 

  • Experimental Verification of Robust Controller for Electronic Governor of Small Gas Engine Generator

    Okamura Koichi , Tanaka Yuya , Takahata Kenji , Yang Jianming

    … There are a few studies regarding the fluctuations in the concentration of bio-methane fuel and load fluctuation of a generator using an approximately 1-kW small gas engine generator. … The GET system is a bio-methane gas production system, utilizing the sustainable resources from a paddy field, without requiring any distinct auxiliary facilities. …

    International Journal of Automation Technology 12(1), 123-131, 2018

    J-STAGE 

  • Verification of Co-Generation Gas Engine Control Law by Combination of Model Matching and Optimal Observer  [in Japanese]

    Okamura Koichi , Tanaka Yuya , Takahata Kenji , Yang Jianming

    … There are few researches to respond to fluctuations in concentration of bio-methane fuel and load fluctuation of a generator using a co-generation gas engine generator of approximately 1kW. … The GET system is a bio-methane gas production paddy field of sustainable resource recycling type, and does not special auxiliary facilities. …

    Transactions of Society of Automotive Engineers of Japan 49(3), 650-655, 2018

    J-STAGE 

  • Optimal run-and-tumble–based transportation of a Janus particle with active steering

    Mano Tomoyuki , Delfau Jean-Baptiste , Iwasawa Junichiro , Sano Masaki

    … Although making artificial micrometric swimmers has been made possible by using various propulsion mechanisms, guiding their motion in the presence of thermal fluctuations still remains a great challenge. …

    Proceedings of the National Academy of Sciences of the United States of America Online Edition 114(13), 2580-2589, 2017-03-14

    IR 

  • Analysis of Loss and Temperature Characteristics of High Power Contactless Transformer due to High-Frequency Magnetic Field Fluctuations  [in Japanese]

    Shimotsu Takuya , Kondo Keiichiro , Ukita Keigo

    … <p>In contactless power transformers, the electric power is transmitted at a high frequency. … In this paper, the influence of the magnetic field and frequency on the equivalent resistance of the coils is evaluated. …

    IEEJ Transactions on Industry Applications 137(4), 350-357, 2017

    J-STAGE 

  • Localized field-aligned currents and 4-min TEC and ground magnetic oscillations during the 2015 eruption of Chile's Calbuco volcano

    Aoyama Tadashi , Iyemori Toshihiko , Nakanishi Kunihito , Nishioka Michi , Rosales Domingo , Veliz Oscar , Safor Erick Vidal

    … About 2 h after the first eruption, a Swarm satellite passed above the volcano and observed enhancement of small-amplitude (~0.5 nT) magnetic fluctuations with wave-packet structure which extends 15° in latitude. … Just after the eruption, geomagnetic fluctuations with the spectral peaks around the vertical acoustic resonance periods, 215 and 260 s, were also observed at Huancayo Geomagnetic Observatory located on the magnetic equator. …

    Earth, Planets and Space (68), 2016-08-31

    IR 

  • Doppler Reflectometer System for Measuring Rotation Velocity of Fluctuation in GAMMA 10

    KOHAGURA Junko , TOKUZAWA Tokihiko , YOSHIKAWA Masayuki , NARITA Kohei , SAKAMOTO Mizuki , NAKASHIMA Yousuke , 小波藏 純子 , 吉川 正志 , 坂本 瑞樹 , 中嶋 洋輔

    … Doppler reflectometry is currently used as a powerful technique to measure the perpendicular (to the magnetic field) velocity of density fluctuation, the radial electric field, and the perpendicular wave number spectrum in many fusion plasma devices. … The first preliminary results of Doppler shifted spectra and radial profiles of the perpendicular velocity of density fluctuations are presented for ICRF start-up plasma with additional ECH. …

    Plasma and Fusion Research (11), 2402022, 2016-03

    IR 

  • Doppler Reflectometer System for Measuring Rotation Velocity of Fluctuation in GAMMA 10

    KOHAGURA Junko , TOKUZAWA Tokihiko , YOSHIKAWA Masayuki , NARITA Kohei , SAKAMOTO Mizuki , NAKASHIMA Yousuke

    … <p>Doppler reflectometry is currently used as a powerful technique to measure the perpendicular (to the magnetic field) velocity of density fluctuation, the radial electric field, and the perpendicular wave number spectrum in many fusion plasma devices. … The first preliminary results of Doppler shifted spectra and radial profiles of the perpendicular velocity of density fluctuations are presented for ICRF start-up plasma with additional ECH. …

    Plasma and Fusion Research 11(0), 2402022-2402022, 2016

    J-STAGE 

  • Energy Flux due to Electromagnetic Fluctuations during Guide Field Magnetic Reconnection

    KUWAHATA Akihiro , INOMOTO Michiaki , YANAI Ryoma , ONO Yasushi

    … <p>Large electromagnetic fluctuations inside the current sheet and large reconnection electric fields are observed during fast magnetic reconnection in the presence of a guide field. … The fluctuations transport 2.5% of the dissipated magnetic energy from the reconnection region. …

    Plasma and Fusion Research 11(0), 1301087-1301087, 2016

    J-STAGE 

  • Study of Efficiency of Battery Energy Storage System  [in Japanese]

    Mizutani Mami , Kobayashi Takenori , Watabe Katsunori , Wada Tomoki

    … <p>A significant increase of renewable energy generation such as photovoltaic and wind power causes fluctuations in frequency and voltage in power grid. … The paper demonstrates seasonal field results of the efficiency measured in an actual 100kW-300kWh BESS. …

    IEEJ Transactions on Power and Energy 136(11), 824-832, 2016

    J-STAGE 

  • Induced Change of Electric Self-potential and Magnetic Field at the Artificial Explosion  [in Japanese]

    Sakai Hideo , Kobayashi Tsuyoshi , Izumi Yoshinori , Nakayama Takeshi , Hattori Katsumi

    … Study of the electric self-potential (SP) and the magnetic field was conducted at the explosion seismic experiment in Ooyama, Toyama Prefecture. … Induced SP changes consisted of two portions, namely, fluctuations with shorter periods (∼10 ms) and fluctuations with longer periods (∼50 ms). …

    IEEJ Transactions on Fundamentals and Materials 136(5), 291-296, 2016

    J-STAGE 

  • Study of Nonlinear Behavior of Low-Frequency MHD Mode Caused by Transition of Radial Electric Field in LHD

    MOON Chanho , IDA Katsumi , TOKUZAWA Tokihiko , TANAKA Kenji , YOSHINUMA Mikirou , KOBAYASHI Tatsuya , INAGAKI Shigeru , ITOH Kimitaka , LHD Experiment Group

    … <p>The response of low-frequency magnetic fluctuations in a transition of radial electric field (<i>E</i><sub>r</sub>) is investigated in the edge region of LHD plasmas. …

    Plasma and Fusion Research 10(0), 3402053-3402053, 2015

    J-STAGE 

  • Numerical Investigation of Pressure Fluctuation Reducing in Draft Tube of Francis Turbines

    Feng W F Li J J , Wu H , Lu J L , Liao W L , Luo X Q

    … The field test of the prototype turbine shows that the main reason is the resonance between the draft tube vortex frequency and the generator natural vibration frequency. … CFD method is adopted to simulate the three-dimensional unsteady flow in the Francis turbine, to calculate pressure fluctuations in draft tube under three schemes and to compare with the field test result of the prototype turbine. …

    International Journal of Fluid Machinery and Systems 8(3), 202-208, 2015

    J-STAGE 

  • ICOPE-15-C047 Dynamics of Non-premixed Flames with Modulations in the Air Flow for a Bluff-body Burner

    Tang Haojie , Zhu Min , Jing Liyue , Zhu Ding

    … The flow field, the reaction zone, the pressure oscillation and heat release rate were recorded by the dynamic data measurement system. … At large amplitude of velocity fluctuations, the continuous recirculation zone disappears, resulting in the variation of the flame transfer function. … These results help to understand the response of the non-premixed flame to fluctuations of air flow and develop combustion instability control techniques. …

    The Proceedings of the International Conference on Power Engineering (ICOPE) 2015.12(0), _ICOPE-15--_ICOPE-15-, 2015

    J-STAGE 

  • D122 Change in Spatio and Temporal Structures of a Fire Plume under Confined Ventilation Conditions  [in Japanese]

    Hattori Yasuo , Matsuyama Ken , Suto Hitoshi , Okinaga Seiji , Onuma Eiji

    … We have experimentally investigated thermal fields in the near-field of a medium-size ethanol pool fire under confined ventilation conditions, which was generated in a compartment poorly ventilated by a mechanical system with a merger negative pressure. … The temperature fluctuations measured with fine thermo-couples shows that the meandering motions yield the increase in temperature fluctuations in low frequency region which is smaller than that with puffing motion just above the center of pool. …

    The Proceedings of the Thermal Engineering Conference 2015(0), _D122-1_-_D122-2_, 2015

    J-STAGE 

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