The effect of high magnetic field on diamagnetic fluid flow has been studied by in-situ optical observation. The Schlieren optics utilizable under high magnetic fields was developed to carry out in-situ observation of the behavior of feeble magnetic fluids. Using a crystal of the diamagnetic aluminum potassium sulfate dodecahydrate, the behavior of the downward flow of high concentration solution in the sample dissolution process was observed. It was found that the direction of diamagnetic fluid flow was changed under spatially varied magnetic field. This phenomenon was understood qualitatively by considering the magnetic force acting on the high concentration solution and the surrounding solution.
To improve thermal power plant efficiency, we proposed a water treatment system with a high gradient magnetic separation (HGMS) system using a superconducting magnet, which is applicable in high-temperature and high-pressure conditions. This is a method to remove the scale from feed-water utilizing magnetic force. One of the issues for practical use of the system is how to extend the continuous operation period. In this paper, we succeeded in solving the problem by eliminating the deviation of captured scale quantity by each filter. In fact, in the HGMS experiment using the solenoidal superconducting magnet, it was shown that a decrease in separation rate and an increase in pressure loss were prevented, and the total quantity of captured scale increased by proper filter design. The design method of the magnetic filter was proposed and will be suitable for long-term continuous scale removal in the feed-water system of the thermal power plant.
Our research is to magnetize the high-T/sub c/ bulk superconductors and to supply magnetic field environment realized by superconducting bulk magnets to various applications. In this paper, we aim to apply the superconducting bulk magnets to the high gradient magnetic separation (HGMS). Using a face-to-face type superconducting bulk magnet system in which a pair of bulk superconductors are oppositely arranged, Y123 bulk superconductors are magnetized by the "IMRA" method (pulsed field magnetization), and consequently, a magnetic field of 1.6 T is achieved between the magnetic poles. Next, HGMS using superconducting bulk magnets is demonstrated. A separation pipe into which filter matrices composed by ferromagnetic wires are stuffed is set between the magnetic poles and the slurry mixed with fine powder of /spl alpha/-hematite (Fe/sub 2/O/sub 3/) particles is flown. As the results of HGMS, over 90% of the Fe/sub 2/O/sub 3/ was separated. Moreover, separation filters have to be washed so that they are not clogged with captured particles. We confirmed that the filter was briefly washed by flowing water after moving the separation pipe from magnetic poles.
We are developing a water processing system for the removal of arsenic from geothermal water. We adopt the coprecipitation method of Fe (III) hydroxide, in which As is adsorpted to the flocks of Fe (III) hydroxide, and the High Intensity and High Gradient Magnetic Separation (HIHGMS) by superconducting magnets to extract the flocks. We demonstrated that the method reduce arsenic to 0.015mg/L that closed to the environmental standard in Japan, from 3.4mg/L and we purified a large amount of water at high speed. We also describe an estimate of a feasible plant for removal of arsenic in the geothermal water for public use.
We have developed a high gradient magnetic separation (HGMS) system to remove arsenic from geothermal water and to supply hot water for public use by using a superconducting magnet. We attained the reduction of arsenic concentration to 0.015 mg/L that is less than the standard for discharge of 0.1 mg/L and slightly larger than the environmental standard of 0.01 mg/L in Japan. The system consists of a pretreatment process that adds extra magnetization to arsenic by chemical reaction, and a reciprocal HGMS filter using a superconducting magnet that extracts magnetized arsenic from the geothermal water. We present the experimental results of the removal system.
We measured the removal efficiency of hematite (Fe/sub 2/O/sub 3/) and iron (III) hydroxide (Fe(OH)/sub 3/) fine particles suspended in water in a high gradient magnetic separation (HGMS) system. Fe/sub 2/O/sub 3/ and Fe(OH)/sub 3/ have relatively small magnetic relative susceptibilities (MKS) near 10/sup -3/ and average particle diameters near 1 /spl mu/m. We demonstrated that HGMS is able to effectively separate weakly magnetized particles.
It is shown by using the cut-vertex method that interference terms between an axial-vector and vector currents are factorized into a short- and long-distance parts. Perturbative QCD corrections to the interference of two contributions, e+e−→Z0→hX and e+e−→γ*→hX, are presented to the next-to-leading order where coefficient functions are calculated to order g2.
We have been developing the scale removal system utilizing superconducting magnet that can remove iron scale from boiler feed-water in a thermal power plant. The scale removal prevents the plants from the reduction in power generation efficiency. Iron oxide scale consists of the ferromagnetic and the paramagnetic particles, and the optimal separation conditions largely differ depending on the magnetic properties of the particles. So, single separation condition may cause the filter blockage by over capture or inadequate capture. We proposed the two-stage magnetic separation according to the magnetic properties of the aggregates, where the ferromagnetic particles are captured in the 1st stage in low magnetic field and field gradient, and then the paramagnetic ones are captured in the 2nd stage in high magnetic field and field gradient. It was shown that two-stage magnetic separation system for the mixture of ferromagnetic and paramagnetic particles is possible by utilizing one superconducting solenoidal magnet.
The heating systems for the new large helical device which has been designed as a joint effort among Japanese universities are reported. The conceptional design of the heating devices and basic hardware structures are discussed. ECH heating system (112 GH z ) with maximum power of around 10MW is proposed to produce and heat the net current-less plasma. For the further heatings, NBI (20 MW, 100 kV, H 0 ) and ICRF (9 MW, 30–90 MH z ) heating systems have been considered. High energy particle loss, which is a fairly serious problem in helical configurations (stellarator/heliotron), have been analyzed numerically. Monte-Carlo calculation shows that, for tangential injection, the beam energy over 100 kV is necessary to obtain the thermalization efficiency of above 60% inside the half radius. On the fast-wave (ICRF) heating, theoretical analysis of the wave field and velocity distribution function, which includes the loss cone effect, has been developed. In the case of 3 He minority heating, the orbit loss problem becomes small than in the case of proton minority heating. From these theoretical analysis and hardware considerations, the required thermalized power of around 20 MW can be obtained by ECH, NBI and ICRF heatings.
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