The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Javad Ghaderia - One of the best experts on this subject based on the ideXlab platform.
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performance of copper oxide distilled water nanofluid in evacuated tube solar collector etsc water heater with Internal Coil under thermosyphon system circulations
Applied Thermal Engineering, 2017Co-Authors: Javad Ghaderia, Nor Azwadi Che Sidik, Alibakhsh Kasaeia, Sepideh Ghaderia, Ami Okhova, Amirabbas Pakzadeh, Syahrullail Samio, Wira Jazai YahyaAbstract:Abstract In this study, the effect of CuO/distilled water nanofluid on the performance of evacuated tube solar collector (ETSC) water heater with Internal Coil under thermosyphon system circulations was experimentally investigated. The volume fraction of nanoparticles was considered at 0.03–0.06%. The mass flow rate of water passing through the Coil was varied from 20 to 60 L/h. ASHRAE standard 86–93 was considered to calculate the efficiency of the collector. From the study, we found that the efficiency of ETSC increase when the nanofluid was used as an absorption medium. CuO nanofluids at 0.03% volume fraction in ETSC gave enhancement up to 14%, when compared to water.
Wira Jazai Yahya - One of the best experts on this subject based on the ideXlab platform.
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performance of copper oxide distilled water nanofluid in evacuated tube solar collector etsc water heater with Internal Coil under thermosyphon system circulations
Applied Thermal Engineering, 2017Co-Authors: Javad Ghaderia, Nor Azwadi Che Sidik, Alibakhsh Kasaeia, Sepideh Ghaderia, Ami Okhova, Amirabbas Pakzadeh, Syahrullail Samio, Wira Jazai YahyaAbstract:Abstract In this study, the effect of CuO/distilled water nanofluid on the performance of evacuated tube solar collector (ETSC) water heater with Internal Coil under thermosyphon system circulations was experimentally investigated. The volume fraction of nanoparticles was considered at 0.03–0.06%. The mass flow rate of water passing through the Coil was varied from 20 to 60 L/h. ASHRAE standard 86–93 was considered to calculate the efficiency of the collector. From the study, we found that the efficiency of ETSC increase when the nanofluid was used as an absorption medium. CuO nanofluids at 0.03% volume fraction in ETSC gave enhancement up to 14%, when compared to water.
Nor Azwadi Che Sidik - One of the best experts on this subject based on the ideXlab platform.
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performance of copper oxide distilled water nanofluid in evacuated tube solar collector etsc water heater with Internal Coil under thermosyphon system circulations
Applied Thermal Engineering, 2017Co-Authors: Javad Ghaderia, Nor Azwadi Che Sidik, Alibakhsh Kasaeia, Sepideh Ghaderia, Ami Okhova, Amirabbas Pakzadeh, Syahrullail Samio, Wira Jazai YahyaAbstract:Abstract In this study, the effect of CuO/distilled water nanofluid on the performance of evacuated tube solar collector (ETSC) water heater with Internal Coil under thermosyphon system circulations was experimentally investigated. The volume fraction of nanoparticles was considered at 0.03–0.06%. The mass flow rate of water passing through the Coil was varied from 20 to 60 L/h. ASHRAE standard 86–93 was considered to calculate the efficiency of the collector. From the study, we found that the efficiency of ETSC increase when the nanofluid was used as an absorption medium. CuO nanofluids at 0.03% volume fraction in ETSC gave enhancement up to 14%, when compared to water.
Yuichi Ogawa - One of the best experts on this subject based on the ideXlab platform.
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Wave Characteristics in the Electron Cyclotron Range of Frequencies in Overdense Plasmas in the Internal Coil Device Mini-RT
Plasma and Fusion Research, 2011Co-Authors: K. Uchijima, Junji Morikawa, Eiichi Yatsuka, Keigo Okabe, Akihiro Honda, Kiyotake Kinjo, Yuichi OgawaAbstract:In the Internal Coil device Mini-RT, overdense plasmas have been observed, and heating by electron Bernstein waves (EBWs) is expected. EBWs, which have no cutoff density, are electrostatic-mode waves converted from the electromagnetic mode. To examine mode conversion in Mini-RT experiments, we are attempting to investigate the propagation of waves in the electron cyclotron range of frequencies (ECRF) in overdense plasmas. We injected diagnostic microwaves (typically 1 GHz) into a plasma produced by 2.45 GHz microwaves and directly measured their characteristics by inserting various probing antennas into the plasma with an interference system. Electromagnetic field measurements revealed a long-wavelength mode in the area with lower density than the upper hybrid resonance (UHR) region. In the area with higher density than that of the UHR region, waves having the characteristics of EBWs were observed; namely, short wavelength (∼20 mm), electrostatic mode, longitudinal polarization, and backward wave mode. These results suggest that EBWs were mode converted from electromagnetic waves at the UHR.
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Construction and Operation of an Internal Coil Device, RT-1, with a High-Temperature Superconductor
Plasma and Fusion Research, 2009Co-Authors: Yuichi Ogawa, Zensho Yoshida, Junji Morikawa, Haruhiko Saito, Sho Watanabe, Y. Yano, S. Mizumaki, Taizo TosakaAbstract:An Internal Coil device called Ring Trap-1 (RT-1) has been constructed to explore an innovative concept for a high-beta plasma based on a new relaxation theory. A high-temperature superconductor (HTS) Bi-2223 tape is employed for the Internal Coil of RT-1. The Coil is cooled to 20 K with helium gas supplied by G-M refrigerators, and charged to a magnetomotive force of 250 kA using an external power supply. For these cooling and charging methods, we have developed several innovative techniques such as a demountable transfer tube system, persistent current switch, detachable electrode, and others. In addition, we have paid much attention to the deterioration of the HTS tape during the fabrication of the Internal Coil. As a result, we have demonstrated that the decay of the persistent current of the Internal Coil is ∼1% during 8 h. The Internal Coil is lifted with a levitation Coil located at the upper region of the vacuum vessel. The Coil position monitored with laser sensors is feedback controlled through the regulation of the levitation Coil current. Stable levitation for a few hours has been demonstrated for various plasma experiments.
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Application of high-temperature superconducting Coil for Internal ring devices
Fusion Engineering and Design, 2006Co-Authors: Yuichi Ogawa, Junji Morikawa, Nagato Yanagi, Toshiyuki Mito, Masataka IwakumaAbstract:Abstract A high-temperature superconducting (HTS) Coil is applied for plasma confinement devices, where plasma is confined with a magnetic field of a floating HTS Coil. The Internal Coil device mini-RT with a BSCCO tape has been constructed, in which the Coil major radius and magnetomotive force are 0.15 m and 50 kA, respectively. The Coil is cooled to 20 K with a helium gas by using a demountable transfer tube and check valve system. The Coil current is directly excited by the external power supply with demountable electrodes. To reduce the heat load, the electrodes were cooled with liquid nitrogen. The levitation experiment of the HTS Coil has been carried out. The position of the HTS Coil is measured by laser sensors, and is feedback-controlled with the levitation Coil current. We have succeeded in levitating the HTS Coil during 1 h with accuracy of less than 20 μm. The magnetic field strength near the Internal Coil is around 0.1 T, and a radio-frequency wave of 2.45 GHz is applied for the plasma production. At the floating condition of the HTS Coil, a high-density plasma with more than 10 17 m −3 , which is higher than the cut-off density of a 2.45 GHz microwave, has been produced. A new device RT-1 with a major radius of 0.25 m and a magnetomotive force of 250 kA is under construction, and a persistent current has been demonstrated. The feasibility on YBCO tape is briefly discussed.
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Plasma Production by Electron Cyclotron Heating on the Internal Coil Device Mini-RT
Japanese Journal of Applied Physics, 2006Co-Authors: Takuya Goto, Junji Morikawa, Eiichi Yatsuka, Yuichi OgawaAbstract:The Internal Coil device Mini-RT (Ring Trap) has been constructed in order to study the extremely high beta plasma confinement predicted in two fluid relaxation theory. Plasma is produced by electron cyclotron heating with a 2.45 GHz, 2.8 kW microwave. Plasma experiments were carried out for two conditions: with a mechanically supported Coil, and with a magnetically levitated one. In the case in which the Internal Coil was mechanically supported, plasma densities up to ne=7×1016 m-3 were produced with a filling gas pressure of pn=4×10-2 Pa, and plasma could not be available at a gas pressure less than 10-2 Pa due to the loss of high energy electrons by the supporting structure. It has been clearly demonstrated that the levitation of the Internal Coil, which was followed by the removal of the supporting structure from the plasma confinement region, improves plasma parameters markedly. The levitation of the Internal Coil enables plasma production at a lower filling pressure ( pn=1.5×10-3 Pa). It also enables over-dense plasma production (ne=1.5×1017 m-3, while cutoff density is 7.6×1016 m-3 for 2.45 GHz microwave). Since the calculation shows that the efficiency of mode conversion from fast X-mode wave to electron Bernstein wave (FX–SX–B conversion) is sufficiently high (~87%) in the Mini-RT device, the over-dense plasma production is thought to be caused by heating with electron Bernstein wave (EBW).
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ECH plasma experiments on an Internal Coil device with a high temperature superconductor Coil
Fusion Science and Technology, 2005Co-Authors: Yuichi Ogawa, Junji Morikawa, K. Ohkuni, Shigeo Yamakoshi, Takuya Goto, Nagato Yanagi, Toshiyuki Mito, Masataka IwakumaAbstract:Self-organization related with relaxation phenomenon is playing an important role in various aspects of magnetic confined plasmas. Recently a relaxation theory including the plasma flow has been developed by Mahajan-Yoshida, and a new relaxation state has been identified. The two-fluid relaxation condition is given by {beta} + (V/V{sub A}){sup 2} = const. To study a self-organized structure with strong plasma flow, we have introduced an Internal Coil device. By inducing a radial electric field with appropriate methods, we could drive a toroidal plasma flow, and confine a high beta plasma in a core region. The Internal Coil device Mini-RT with a high temperature superconductor(HTS) Coil(Rc=0.15m, Ic=50kA) has been constructed. The vacuum chamber is 1 m in diameter and {approx}0.7 m in height. The magnetic field strength near the Internal Coil is around 0.1 T, and a radio-frequency wave of 2.45 GHz is applied for the plasma production. We have started ECH plasma experiments with the Coil supported mechanically. The electron density, which has a peak near the Internal Coil, is of order 10{sup 16} m{sup -3}, reaching the cut-off density of the microwave. While, the electron temperature is of order 10 eV with a broad profile. Estimated energy confinement timemore » is of order 10{sup -(5-6)} sec. The levitation experiment of the HTS Coil has been carried out. The position of the HTS Coil is measured with laser sensors, and is feedback-controlled with the levitation Coil current. We have succeeded to levitating the HTS Coil during one hour with an accuracy of less than 20 {omega}m. A preliminary experiment for the plasma production at the floating condition of the HTS Coil has been initiated. It is affirmed that the levitation system works well and plasma with separatrix configuration is produced.« less
Alibakhsh Kasaeia - One of the best experts on this subject based on the ideXlab platform.
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performance of copper oxide distilled water nanofluid in evacuated tube solar collector etsc water heater with Internal Coil under thermosyphon system circulations
Applied Thermal Engineering, 2017Co-Authors: Javad Ghaderia, Nor Azwadi Che Sidik, Alibakhsh Kasaeia, Sepideh Ghaderia, Ami Okhova, Amirabbas Pakzadeh, Syahrullail Samio, Wira Jazai YahyaAbstract:Abstract In this study, the effect of CuO/distilled water nanofluid on the performance of evacuated tube solar collector (ETSC) water heater with Internal Coil under thermosyphon system circulations was experimentally investigated. The volume fraction of nanoparticles was considered at 0.03–0.06%. The mass flow rate of water passing through the Coil was varied from 20 to 60 L/h. ASHRAE standard 86–93 was considered to calculate the efficiency of the collector. From the study, we found that the efficiency of ETSC increase when the nanofluid was used as an absorption medium. CuO nanofluids at 0.03% volume fraction in ETSC gave enhancement up to 14%, when compared to water.