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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.

In the boiler feed-water system of thermal power plants, iron oxide scale is generated due to the corrosion of piping, which decreases the effectiveness of the heat exchanger in the boiler and contributes to reduced power generation efficiency. Scale removal can prevent this phenomenon, which consequently results in decreased carbon dioxide emission. In a previous study, an iron scale removal system was developed using superconducting magnets, and high-gradient magnetic separation (HGMS) experiments were conducted using the height difference between the inflow and outflow tanks. As a result, particles were intensively captured by the filters at the inflow side. We succeeded in eliminating this capture by properly controlling the applied magnetic field. However, because the suspension also flowed due to the height difference in this experiment, the problems of partial blockage of the filter and the resulting decrease in the flow rate were not resolved even under the controlled magnetic field. In this study, HGMS experiments were conducted under a constant flow rate with a large pump in a large-scale system having a filter diameter of 300 mm to simulate a boiler feed-water system or chemical cleaning line. Furthermore, we investigated the feasibility of the large-scale HGMS system and elucidated the scale-up effect on the amount captured and the spatial distribution of the captured particles on the filters. Based on these results, a plant-scale HGMS system (800 mm filter diameter) was designed.

We have been developing a scale removal system utilizing a superconducting magnet that can remove the iron oxide scale from the boiler feed-water in the thermal power plants. Scale removal can prevent a decrease in the power generation efficiency and contribute to reduce the carbon dioxide emissions. In our previous study, we conducted the large-scale experiments for practical use, but model particles were intensively captured by the inflow side filter. In this paper, we succeeded to homogenize the distribution of captured particles in the filter stacks by controlling the applied magnetic field strength. In addition, magnetic field strength dependency of filter blockage was examined in the lab-scale experiments to clarify a detailed mechanism of blockage.

In Eqs. (1-2), t is the pointing time, A is the amplitude (distance) to the target, W is the target size and a, b are constants that depend on experiment conditions. ID is larger as A is larger and/or W is smaller. Values of a and b in Eq. (1) are determined by sampling (A, W, t) data and applying the linear regression analysis to the data. Eq. (2) shows that ID values are the same for (A, W) and (nA, nW) where n > 0. This research is motivated by recent smart phones that employ touch UIs. Compared with other touch screen devices such as tablet PCs, mobile phones have smaller screens so that widgets on mobile phone screens are likely to be smaller. Widgets can be designed for devices with various screen sizes so that theoretical ID values in Eq. (2) are consistent among the devices: larger/smaller sizes & distances for larger/smaller screens. If ID in Eq. (2) is an appropriate index of actual pointing difficulty independently of screen sizes, users’ pointing performances on the same device are consistent among widget designs (A, W) and (nA, nW): note that a, b in Eq. (1) are constant (independent to ID) so that a, b must be the same for two data sets sampled with the two widget designs (A, W) and (nA, nW). The aim of this research is to investigate whether the above is true: appropriateness of the ID formulation in Eq. (2) is evaluated from the viewpoint of dependency on screen sizes, by experiments with participants. Limitations of Fitts’ law have been researched and extensions have been proposed. For example, an extension for 2D pointing tasks was proposed (MacKenzie & Buxton, 1992). Our research aims at investigating possible limitations on screen sizes. A related research was previously reported (Oehl et al., 2007). They investigated how display size influenced pointing performances on a touch UI and reported that in large displays a fast and comparably accurate execution was chosen in contrast to a very inaccurate and timeconsuming style in small displays. In their research the size of small screen was 6.5”, and only a large screen touch UI device was utilized for user experiments: screen sizes were

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.

We are developing a superconducting magnetic separation system to remove scale or iron oxide from boiler feedwater in thermal power plants. The reduction of scale improves energy conversion efficiency of thermal power plants and reduces discharged CO 2 . We have studied suitable installation locations and operation conditions and examined the separation ability of the system located near the boiler where the water is at high temperatures and pressures. We have concluded that the magnetic separation system is effective to remove scale of boiler feedwater and that the use of a superconducting magnet is essential for the system.

A Superconducting High Gradient Magnetic Separation (HGMS) system is proposed for treatment of feed-water in thermal power plant [1]. This is a method to remove the iron scale from feed-water utilizing magnetic force. One of the issues for practical use of HGMS system is to extend continuous operation period. In this study, we designed the magnetic filters by particle trajectory simulation and HGMS experiments in order to solve this problem. As a result, the quantity of magnetite captured by each filter was equalized and filter blockage was prevented. A design method of the magnetic filter was proposed which is suitable for the long-term continuous scale removal in the feed-water system of the thermal power plant.

Effects of magnetic fields on thermal convection in conductive aqueous solutions at ambient temperatures have been studied through heat transport measurements. The suppression of thermal convection...

By the accident of Fukushima Daiichi Nuclear Plant, all the nuclear plants have stopped in Japan. As a result, the operation rate of thermal power plants has been increased. It caused growth in CO 2 emission, which requires some kind of countermeasure. We focused on the iron oxide scales deposited on the piping system and boiler which declines the heat exchange efficiency of thermal power plants. In this study we attempt to remove the iron scales from the piping system and the boiler to maintain the power generation efficiency. In the current thermal plant treated by All Volatile Treatment (AVT) the iron elutes to the feed water in the low-temperature part which changes into iron ion or the paramagnetic fine iron oxide particles. On the other hand at the high-temperature part the main component of the scales is large ferromagnetic particles of magnetite. Therefore the magnetic separation at the high-temperature part is the more effective to remove the scale than that at the low-temperature part. For the reason, the existing method using the electromagnetic filter placed in the low-temperature part is not effective to remove the scales. We studied the high gradient magnetic separation (HGMS) at high-temperature part to remove a large amount of the scale. In this study, we assumed to install the HGMS system using the superconducting magnet at the inlet of the boiler.

The magneto-Archimedes separation allows for separating mixtures of feeble magnetic materials into its components based on the difference of their densities and magnetic susceptibilities. So far, this technique was applied for the separation of relatively large particles of several millimeters in diameter. Here we apply this technique experimentally to the simultaneous quantitative analysis of multiple micrometer-sized particles in a fluid. It was confirmed that the magneto-Archimedes separation can be applied for the separation of mixture of microspheres larger than 20 μm. Further high performance separation efficiency is expected with the optimization of separation conditions including the control of the spatial distribution of the magnetic field.

Particle swarm optimization (PSO) is a well-known instance of swarm intelligence algorithms and there have been many researches on PSO. In this paper, the author proposes an extension of PSO for solving fuzzy-valued optimization problems. In the proposed extension, genotype values (i.e. values in particle position vectors) are not real numbers but fuzzy numbers. Search processes in PSO are extended so that PSO can handle genotype instances with fuzzy numbers. The proposed method is experimentally applied to evolution of neural networks with fuzzy weights and biases. Experimental results showed that fuzzy neural networks evolved by the proposed method could model hidden target fuzzy functions despite the fact that no training data was explicitly provided.

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.

Precise protein structure determination provides significant information on life science research, although high-quality crystals are not easily obtained. We developed a system for producing high-quality protein crystals with high throughput. Using this system, gravity-controlled crystallization are made possible by a magnetic microgravity environment. In addition, in-situ and real-time observation and time-lapse imaging of crystal growth are feasible for over 200 solution samples independently. In this paper, we also report results of crystallization experiments for two protein samples. Crystals grown in the system exhibited magnetic orientation and showed higher and more homogeneous quality compared with the control crystals. The structural analysis reveals that making use of the magnetic microgravity during the crystallization process helps us to build a well-refined protein structure model, which has no significant structural differences with a control structure. Therefore, the system contributes to improvement in efficiency of structural analysis for “difficult” proteins, such as membrane proteins and supermolecular complexes.

A quasi-microgravity environment appears in a high-field superconducting magnet bore where a large magnetic force counterbalances gravity acting on a diamagnetic substance. This suppresses convection of the diamagnetic solution in the crystallization cell placed in the bore from which protein crystals precipitate. A 16 T class superconducting magnet has been developed with a special coil configuration; one of the component coils produces a magnetic field the direction of which is opposite to that of the other coils. Thus, a large magnetic field gradient occurs, creating a magnetic force large enough to levitate water and hinder convection. This magnet system is operated in persistent mode, which is adequate for a rather time-requesting crystallization process of proteins. Preliminary experiments have shown that the protein crystallization process is substantially retarded in the magnetic force field.

The magnetic chromatography (MC) is a very useful system for an ion and/or fine magnetic particle separation due to its strong magnetic field gradients in a very small flow channel. We have not only developed the MC system to separate the fine particles and ions, we have also developed the numerical analysis computer code based on the fluid dynamics and electromagnetism to investigate the separating characteristics and to optimize design of magnetic column. In this paper, we studied MC technology for magnetic particles and ion separations using micro-scale magnetic column with ferromagnetic wires experimentally. The influences of the strength of magnetic gradient, flow velocity and coefficient of viscosity of solvent were studied by the developed computer code.

Alumina with nanoholes was prepared by anodic oxidation of aluminium and subsequently the synthesis of Fe nanofibers was attempted using nanoholes in alumina as a template. Various Fe nanofibers were synthesized by electroplating into alumina templates and subsequent chemical treatments in mixed-acid solutions to remove the templates. Obtained Fe nanofibers had the dimension with 20 nm-30 nm in diameters and typically 500 nm-2 μm in length. Effect of anodic oxidation treatments for a template on the microstructure of Fe nanofibers was examined. The length of Fe nanofibers could be changed by modifying the synthetic conditions, such as anodic oxidation times and electroplating times.

In order to make sure the great potential of steelmaking slag as a new phosphorus resource, domestic phosphorus material flow in Japan including iron and steel industry has been investigated based on the statistical data on 2002. It has been demonstrated that phosphorus in the steelmaking slag is almost equivalent with that in the imported phosphate rock in the view points of the amount and the concentration. Phosphorus exists mainly in the form of calcium-phosphate or its solid solution with calcium-silicate rather than the FetO rich liquid phase in the slag and exhibits remarkable segregation in the solidified slag. If the strong magnetic field is applied to the crushed slag, precipitated calcium-phosphate solution phase can be separated from FetO matrix phase due to the large difference of each magnetic property. It has also been indicated by the Waste Input–Output model that the phosphorus recovery from steelmaking slag by the new process proposed in the present work has great environmental and economical benefits.

Phase relations in the Fe2O3-FeTiO3-TiO2 system were investigated by equilibrating synthetic samples in evacuated sealed quartz tubes at a temperature of 1373 K. The equilibrium partial pressure of oxygen was measured by the electromotive force (EMF) method in the temperature range of 1273 to 1373 K. The phase diagram and oxygen partial pressure diagram in the titanium-iron-oxygen ternary system were then constructed at 1373 K. Rutile extraction from natural ilmenite ore was discussed from the thermodynamic viewpoint. It is found that rutile can be produced from common natural ilmenite ores not only by the reduction as the conventional titanium-rich slag process but also by an oxidation. Then, the oxidation experiment was conducted in air using Australian ilmenite ore to obtain rutile as one of the coexistent phases. Magnetic separation and leaching experiments for synthesized pseudobrookite and reagent rutile were conducted to confirm the possibility of separation of rutile from pseudobrookite. A new rutile extraction process was then proposed.

A computational fluid dynamics (CFD) model was developed for High Gradient Magnetic Separation (HGMS) of particles in liquids flowing through magnetic filters. Using this model, we simulated the effect of fluid flow, magnetic forces, and particle diffusion on the particle filtration efficiency in an HGMS liquid particle filter. By simulating capture efficiency of the simple configuration, the overall filtration efficiency of HGMS filters can be determined. This paper describes this numerical model and simulation results for an HGMS liquid particle filter.

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 aim to apply the superconducting bulk magnets to high gradient magnetic separation technique. Two bulk magnets are face-to-face arranged and a pipe stuffed magnetic filters composed of ferromagnetic wires is placed between the magnetic poles. We setup the magnetic separation system and test it using slurry mixed with hematite particles (Fe2O3). Y123 bulk superconductors are magnetized by the “IMRA” method (pulsed-field magnetization), and consequently a magnetic field of 1.59 T is generated at the center of 20 mm gap between the magnetic poles. As a result of experiment on the magnetic separation, hematite particles of over 90% were removed from slurry at the flow rate of 2 l/min.

An intense magnetic field generator yielding 3.15 T in the open space between the magnetic poles has been constructed by using a pair of melt-processed bulk superconductors as trapped field magnets. The field was measured in a 2 mm gap between the magnetic poles set face-to-face after the pulsed-field magnetization “IMRA” method. This field generator is composed of Sm-based 123 compounds, vacuum pumps, pulsed-field coils and GM refrigerators with compressors. The system can be used in various applications. We investigated, for instance, the application to a high gradient magnetic separation system. It was found that the alpha hematite fine particles mixed in the flowing water was completely removed by this technique which was operated in the field of 1.7 T in the gap of 20 mm.

A superconducting permanent magnet system capable of generating strong magnetic fields has been constructed by using melt-processed bulk superconductors as trapped field magnets. The trapped field in the open space between two magnetic poles that are set face to face has reached 3.15 T when magnetized by a pulsed-field magnetization (PFM) technique. That was operated at 30 K attained by GM-cycle refrigerators. The performance exceeds that of conventional rare earth magnets or large scale electromagnets by far. It was found that the iteratively magnetizing pulsed field operation with reducing amplitude (IMRA) method is very effective in magnetizing the bulk superconductors. The magnet system can be used as a high field generator in various applications.

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 have developed a superconducting High Gradient Magnetic Separation (HGMS) system to remove endocrine disrupters from water. The system was able to purify 70 L of endocrine disrupter-polluted water within about 10 min without generating any secondary waste. The system consists of pretreatment processes to form magnetized compounds with endocrine disrupters, and an HGMS device to extract them from water by using a strong magnetic force. We produced novel adsorbent made of micron-sized ferric oxide particles that are not only magnetic but also hydrophobic. Because some endocrine disrupters are hydrophobic as well, the ferric oxide particles adsorb endocrine disrupters eluted in water according to hydrophobic interaction. We succeeded in decreasing bisphenol A concentrations in the fortified water from 69 to 16 ng/L and nonylphenol from 7.0 to 0.9 mg/L. Furthermore, we have successfully demonstrated that we could regenerate the ferric oxide particles, so that they can be re-used for adsorption of endocrine disrupters in water.