The objective of this study is to separate dyes in wastewater with high efficiency and speed using high-gradient magnetic separation via a superconducting bulk magnet. Two main technologies are necessary for this magnetic separation: one is a magnetic-seeding technology that provides the substance with ferromagnetism, and the other is a magnetic-separation technology that uses a superconducting magnet and magnetic filters. In order to separate the organic dyes, it is necessary to clarify the mechanism of magnetic seeding, and to design a suitable magnetic-seeding method for each kind of dye. Six kinds of dyes widely used in industry were used to investigate the possibility of magnetic seeding, and the interaction mechanism between the dyes and ferromagnetic particles. The results show that electrostatic interaction was one of the main interactions between the organic dyes and ferromagnetic particles. Based on the results, the possibility of practical application of the continuous magnetic separation systems was examined in a model experiment using a superconducting bulk magnet.
Side-effects and the reduced effect of drugs due to their diffusion, such as those involved with anticancer agents, are serious issues in medication. To solve these problems, it is necessary to control the drugs quantitatively, spatially and temporally within the human body. The magnetic drug delivery system (MDDS) is one technology that can make this possible. In this system, ferromagnetic drugs that are injected into a blood vessel are directed to the diseased part via an external magnetic force. This is achieved using a superconducting bulk magnet and ferromagnetic needle. The ultimate goal of our study is to further develop the MDDS, and fundamental experiments to reinforce the effectiveness of the MDDS were conducted. To estimate the magnetic force required to accumulate ferromagnetic particles in the blood vessel, particle distribution in limited biomedical tissues was calculated. To check the validity of the calculations, an experiment relating to the accumulation of ferromagnetic particles in a model tissue consisting of glass beads packed in a glass tube was conducted. Based on these results, local accumulation using a permanent magnet system with a HTS bulk magnet was performed in a rat liver.
Heat transfer characteristics in He II have been investigated in relation to superheating. When a good thermal conductor in a narrow two-dimensional channel is heated above the critical heat flux of the λ-transition, superheated He I nucleates in the hottest area of the conductor covered with superheated He II. The spread of superheated He I, which has low thermal conductivity, forms an intermediate state in which superheated He I coexists with superheated He II. Superheated He I together with superheated He II is apparently stabilized since part of the heat cut off by superheated He I tends to flow in the conductor. Higher heat input turns the intermediate state into a mixed state where superheating and boiling alternate irregularly. (Translation of the article originally published in Cryogenics 49 (2009) 700-706)