On-site experimentation of high gradient magnetic separation (HGMS) for arsenic removal from geothermal water has been conducted using a high-T/sub c/ superconducting magnet. This development of an effective method for decontamination of geothermal water is currently being done at the Kakkonda geothermal power plant in Shizukuishi, Iwate, Japan. In order to enhance the magnetic properties of the arsenic-containing particles in geothermal water, three different pretreatment methods were used: (I) the ferrite formation method; (II) the ferric hydroxide coprecipitate method; and (III) the modified ferric hydroxide coprecipitate method. The conditions of the HGMS experiments were a 1.7 T applied magnetic field and 100/spl deg/C water at a flow rate of 10 L/min. Percentages of the arsenic-removal were strongly dependent on the pretreatment methods, because of a very small magnetization of the arsenic. Arsenic-removal rates of 40%, 80%, and 90% were obtained by pretreatments I, II, and III, respectively. Although the environmental standard for arsenic is 0.01 mg/L, corresponding to a 99% removal rate, could not be achieved in the present experiments, it can be thought that HGMS substantiates the achievement of environmental standards for arsenic, if an optimized pretreatment method is taken.
The new data on charged-particle inclusive cross sections obtained by the TASSO and MARK II detectors in the ${e}^{+}{e}^{\ensuremath{-}}$ annihilation process are analyzed in the framework of perturbative QCD. In the leading logarithmic order there results $\ensuremath{\Lambda}=0.9\ensuremath{-}1.5$ GeV for the scale parameter, but this reduces to $\ensuremath{\Lambda}=0.4\ensuremath{-}0.6$ GeV if the higher-order correction in the $\stackrel{-}{\mathrm{MS}}$ scheme is included. The obtained value of ${\ensuremath{\Lambda}}_{\stackrel{-}{\mathrm{MS}}}$ is slightly larger than but still consistent with that determined from the data of deep-inelastic electron and neutrino scatterings.
We have developed a system that uses a superconducting magnet to remove arsenic from geothermal water. The advantages of applying a high-field, high-gradient magnetic separator (HGMS) and a reciprocating high-gradient magnetic separator for practical use are presented. Finally, we demonstrate that the capture efficiency of the HGMS does not depend on dimensions, and show that properties of a large HGMS plant can be estimated from our experimental results.
A workbench magnet that generates magnetic fields on a room-temperature (RT) plate was developed. The magnet did not have a RT bore. The improvement of accessibility to magnetic fields has made several types of processing and measurement easier. The magnet provides external fields, magnetic fields in the vicinity of the top of a winding, of a solenoid coil on the RT plate. The external fields depend strongly on the gap between the RT plate and the top of the winding. The magnet was a cryocooled superconducting magnet with a 1-W GM cryocooler at 4 K. The magnet successfully generated magnetic fields of over 3 T at the center of the RT plate. The magnet could generate magnetic fields more than twice the surface magnetic fields of permanent magnets with the same accessibility.
A full system of 1 kWh/1 MW superconducting magnetic energy storage (SMES) has been completed early this year. This SMES is the first step to the realization of practical SMES system for power line stabilization. Main points in its design are two module type arrangement of six coils having three coils and one converter as one unit of module, modified-D-shaped coils with mechanical supports, liquid helium vessel type cooling of coils, and high-temperature superconducting current leads. The first test experiment was carried out on the site recently. The above design points were examined. A preliminary test for power line control was also made in the distribution line at the site. Satisfactory results were obtained.
Recently, high-performance permanent magnets based on RE-TM-Z intermetallice (RE rare earth, TM: transition metal and Z light element) have been developed. One of their characteristic properties, the high energy product, could be performed by the high remanence and high coercive force. The mechanism of high saturation magnetization connected with high remanence has been well known from many fundamental studies, but the mechanism of coercive force is little known yet. In general, the coercive force H. has been denoted as follows [1]:
Superconductive Magnetic Energy Storage (SMES) coils for diurnal load leveling and system peaking are envisioned to operate at hundreds of thousands of amperes and a few kilovolts. The interface between the SMES coil and the electric utility is envisioned to be Graetz bridges using SCR switches. Many parallel SCR switches or bridge units will have to operate in parallel because of the high operating current of the coil. Current balancing on parallel Graetz bridges driving a single 8-hy superconducting coil has been achieved on a laboratory model using delay-angle control with an LSI 11/2 microprocessor and external digital control hardware.
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