Synopsis : Recently, several novel techniques for creating superconducting joints between two REBCO-CCs have been suggested. These techniques include long-time oxidization annealing to compensate the oxygen deficiency of REBCO due to the high processing temperature. In this paper, a superconducting joint was achieved via a one-time heat treatment at the low temperature of 525ºC without oxidization annealing. The jointed GdBCO-CCs were prepared in three steps. The first step is that Eu–Ba–Cu–O raw material was placed between Ag-removed Gd123 layers of the CC. In the second step, the sample was mechanical pressurized using two plates of metal. Finally, the sample was heat-treated at 525ºC in KOH vapor. All steps were performed at ambient pressure. The jointed sample was bonded finely and showed T conset = 76.7 K and T czero = 57.5 K inclusive of the jointed region. From XRD observation of the jointed region in the samples, both GdBCO-CC and EuBCO-pressed materials contained incomplete RE123, RE247 and RE124 phases.
{"title":"Superconducting Joint for REBCO-Coated Conductors without Oxidization Annealing via Low-temperature Synthesis Reaction Using Potassium Hydroxide","authors":"S. Funaki, Y. Miyachi, Y. Yamada","doi":"10.2221/jcsj.55.275","DOIUrl":"https://doi.org/10.2221/jcsj.55.275","url":null,"abstract":"Synopsis : Recently, several novel techniques for creating superconducting joints between two REBCO-CCs have been suggested. These techniques include long-time oxidization annealing to compensate the oxygen deficiency of REBCO due to the high processing temperature. In this paper, a superconducting joint was achieved via a one-time heat treatment at the low temperature of 525ºC without oxidization annealing. The jointed GdBCO-CCs were prepared in three steps. The first step is that Eu–Ba–Cu–O raw material was placed between Ag-removed Gd123 layers of the CC. In the second step, the sample was mechanical pressurized using two plates of metal. Finally, the sample was heat-treated at 525ºC in KOH vapor. All steps were performed at ambient pressure. The jointed sample was bonded finely and showed T conset = 76.7 K and T czero = 57.5 K inclusive of the jointed region. From XRD observation of the jointed region in the samples, both GdBCO-CC and EuBCO-pressed materials contained incomplete RE123, RE247 and RE124 phases.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131435466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis: The superconducting joint is utilized for superconducting magnets operated using persistent current mode. MRI, NMR, and MCZ, which are commercial products in the superconducting market, are also operated using persistent current mode, and are constructed with low-temperature superconducting wires. Since these magnets need a constant and stable magnet field for long period of time, the superconducting joints must have extremely low resistivity, lower than 10-11 Ω to avoid rapid degradation of the magnetic field. Commercial low-temperature superconducting wires have NbTi or Nb3Sn filaments embedded in stabilizing materials such as copper or aluminum matrixes. To realize a low-resistance joint, the stabilizing materials are removed and the mutual filaments are directly jointed. This manuscript introduces superconducting joint methods for low-temperature superconducting wires, which has been developed by the superconducting magnet manufactures and related R&D institutions.
{"title":"Superconducting Joint Technology for a Low-temperature Superconducting Wire","authors":"Mukoyama Shinichi","doi":"10.2221/jcsj.55.255","DOIUrl":"https://doi.org/10.2221/jcsj.55.255","url":null,"abstract":"Synopsis: The superconducting joint is utilized for superconducting magnets operated using persistent current mode. MRI, NMR, and MCZ, which are commercial products in the superconducting market, are also operated using persistent current mode, and are constructed with low-temperature superconducting wires. Since these magnets need a constant and stable magnet field for long period of time, the superconducting joints must have extremely low resistivity, lower than 10-11 Ω to avoid rapid degradation of the magnetic field. Commercial low-temperature superconducting wires have NbTi or Nb3Sn filaments embedded in stabilizing materials such as copper or aluminum matrixes. To realize a low-resistance joint, the stabilizing materials are removed and the mutual filaments are directly jointed. This manuscript introduces superconducting joint methods for low-temperature superconducting wires, which has been developed by the superconducting magnet manufactures and related R&D institutions.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133363066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"会長就任にあたって","authors":"S. Akita","doi":"10.2221/jcsj.55.247","DOIUrl":"https://doi.org/10.2221/jcsj.55.247","url":null,"abstract":"","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128298825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis: The superconducting joint is a key technology to achieve persistent current operation for MRI and NMR magnets, thereby enabling to obtain higher resolution and sensitivity. A persistent current system including a superconducting joint, a persistent current switch and a double pancake coil fabricated with a REBCO tape was prepared by Furukawa Electric Co., Ltd. The magnetic-field decay behaviors during persistent current operation were observed in external fields of 0 and 1 T at 20 K. In a self-field, the decay rate of the persistent current excited up to 170 A reached 1.2 ppm/h after operating for five days, corresponding to a resistance of 5.1 10-13 . From the current–voltage characteristics obtained from the magnetic field decay, it was found that the decay behavior of the persistent current is dominated by joint resistance in the case of high-load operation, but dominated by the shielding current in the case of low-load region of the operating current.
{"title":"Performance Test of HTS Superconducting Joint for Persistent Current Operation of REBCO Coil","authors":"Kohki Takahashi, S. Awaji","doi":"10.2221/jcsj.55.268","DOIUrl":"https://doi.org/10.2221/jcsj.55.268","url":null,"abstract":"Synopsis: The superconducting joint is a key technology to achieve persistent current operation for MRI and NMR magnets, thereby enabling to obtain higher resolution and sensitivity. A persistent current system including a superconducting joint, a persistent current switch and a double pancake coil fabricated with a REBCO tape was prepared by Furukawa Electric Co., Ltd. The magnetic-field decay behaviors during persistent current operation were observed in external fields of 0 and 1 T at 20 K. In a self-field, the decay rate of the persistent current excited up to 170 A reached 1.2 ppm/h after operating for five days, corresponding to a resistance of 5.1 10-13 . From the current–voltage characteristics obtained from the magnetic field decay, it was found that the decay behavior of the persistent current is dominated by joint resistance in the case of high-load operation, but dominated by the shielding current in the case of low-load region of the operating current.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124589077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis : In order to prepare the jointing of high-temperature superconducting wires at relative room temperature, we developed elemental technologies. It was found that the superconducting jointing was difficult to realize in stacked YBCO/NbTi thin films. However, we succeeded in reducing the jointing resistance by inserting an Ag layer between the YBCO and NbTi thin films, and confirmed that the resistance was less than the PPMS measurement limit of 10 -4
{"title":"Preparation of Epitaxial NbTi Thin Films at Room Temperature and Elemental Technologies for Superconducting Joint","authors":"H. Takashima, K. Tonooka, Y. Yoshida, M. Furuse","doi":"10.2221/jcsj.55.280","DOIUrl":"https://doi.org/10.2221/jcsj.55.280","url":null,"abstract":"Synopsis : In order to prepare the jointing of high-temperature superconducting wires at relative room temperature, we developed elemental technologies. It was found that the superconducting jointing was difficult to realize in stacked YBCO/NbTi thin films. However, we succeeded in reducing the jointing resistance by inserting an Ag layer between the YBCO and NbTi thin films, and confirmed that the resistance was less than the PPMS measurement limit of 10 -4 ","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133476092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis: An investigation as to whether or not superconducting high-gradient magnetic separation is capable of reducing the volume of cesium in contaminated soil is reviewed. This unique physical method can selectively remove paramagnetic 2:1-type clay minerals that strongly trap cesium inside the interlaminar site from soil suspensions. However, there are technical issues, such as wide particle size distribution and particle aggregation. To solve these problems, advanced pretreatments of advanced classification and alkaline dispersion treatments were performed, and the radioactivity concentration reduction rate was successfully increased. Based on the results, issues for practical application were discussed.
{"title":"Possibility of Applying Superconducting High-gradient Magnetic Separation to Volume Reduction of Cesium-contaminated Soil","authors":"Y. Akiyama, N. Nomura, F. Mishima, S. Nishijima","doi":"10.2221/jcsj.55.172","DOIUrl":"https://doi.org/10.2221/jcsj.55.172","url":null,"abstract":"Synopsis: An investigation as to whether or not superconducting high-gradient magnetic separation is capable of reducing the volume of cesium in contaminated soil is reviewed. This unique physical method can selectively remove paramagnetic 2:1-type clay minerals that strongly trap cesium inside the interlaminar site from soil suspensions. However, there are technical issues, such as wide particle size distribution and particle aggregation. To solve these problems, advanced pretreatments of advanced classification and alkaline dispersion treatments were performed, and the radioactivity concentration reduction rate was successfully increased. Based on the results, issues for practical application were discussed.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134301286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis : This article reviews the current status and recent progress of magnetic separation technologies using superconducting magnets and conventional magnets. In this article, firstly, the research and development history of magnetic separation technologies is reviewed. Secondly, the main component technologies for magnetic separation, such as options for magnetic separation methods, magnet devices as magnetic-field generators, magnetic seeding methods, magnetic filters and magnetic separation methods utilizing the Magneto-Archimedes effect, are summarized. Thirdly, the contents of presentations at the CSJ and CSSJ conferences held from 2006-2018 are summarized. Based on this summary, the status quo of the research and development of magnetic separation technologies in Japan is analyzed. It is confirmed that the component technologies for magnetic separation have advanced well and many new applications of magnetic separation using superconducting magnets have been developing. It is worth noting that the magnetic separation method removing radioactive Cs from contaminated soil using a superconducting magnet has been developed. In China and Korea, the research and development of magnetic separation technologies have continued as well. Particularly in China, there is much interest in magnetic separation since the environmental pollution that has become apparent with economic development has become serious. Through the technical review in this article, it is found that recent magnetic separation technologies have advanced to the level where social implementation is possible. Sustainable Development Goals (SDGs) and promotion of sustainable economies are the tailwinds for spreading magnetic separation with superconducting technology because of contributions to the environment, materials recycling, CO 2 reduction, cost reduction and innovation.
{"title":"Current Status of Magnetic Separation Using Superconducting Technology and Future Social Needs","authors":"Tsuneo Watanabe, S. Fukui","doi":"10.2221/jcsj.55.149","DOIUrl":"https://doi.org/10.2221/jcsj.55.149","url":null,"abstract":"Synopsis : This article reviews the current status and recent progress of magnetic separation technologies using superconducting magnets and conventional magnets. In this article, firstly, the research and development history of magnetic separation technologies is reviewed. Secondly, the main component technologies for magnetic separation, such as options for magnetic separation methods, magnet devices as magnetic-field generators, magnetic seeding methods, magnetic filters and magnetic separation methods utilizing the Magneto-Archimedes effect, are summarized. Thirdly, the contents of presentations at the CSJ and CSSJ conferences held from 2006-2018 are summarized. Based on this summary, the status quo of the research and development of magnetic separation technologies in Japan is analyzed. It is confirmed that the component technologies for magnetic separation have advanced well and many new applications of magnetic separation using superconducting magnets have been developing. It is worth noting that the magnetic separation method removing radioactive Cs from contaminated soil using a superconducting magnet has been developed. In China and Korea, the research and development of magnetic separation technologies have continued as well. Particularly in China, there is much interest in magnetic separation since the environmental pollution that has become apparent with economic development has become serious. Through the technical review in this article, it is found that recent magnetic separation technologies have advanced to the level where social implementation is possible. Sustainable Development Goals (SDGs) and promotion of sustainable economies are the tailwinds for spreading magnetic separation with superconducting technology because of contributions to the environment, materials recycling, CO 2 reduction, cost reduction and innovation.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116921409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis : The magneto-Archimedes effect is a technique to enhance the effect of the magnetic force acting on materials by considering the influence of the surrounding medium. Application of this technique as a way of materials separation is known as the magneto-Archimedes separation. The magneto-Archimedes separation enables the separation of many different materials into each component based on the differences in their magnetic susceptibilities and densities irrespective of the particle size. In this topical review, the principle of the magneto-Archimedes effect and its application as a way to separate materials are described and some other examples applying the magneto-Archimedes effect are introduced.
{"title":"Magneto-Archimedes Effect and Its Applications","authors":"N. Hirota","doi":"10.2221/jcsj.55.185","DOIUrl":"https://doi.org/10.2221/jcsj.55.185","url":null,"abstract":"Synopsis : The magneto-Archimedes effect is a technique to enhance the effect of the magnetic force acting on materials by considering the influence of the surrounding medium. Application of this technique as a way of materials separation is known as the magneto-Archimedes separation. The magneto-Archimedes separation enables the separation of many different materials into each component based on the differences in their magnetic susceptibilities and densities irrespective of the particle size. In this topical review, the principle of the magneto-Archimedes effect and its application as a way to separate materials are described and some other examples applying the magneto-Archimedes effect are introduced.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115960529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synopsis : To improve a biological wastewater process, magnetic separation was applied to a biological wastewater treatment process. An aerobic biological wastewater treatment process utilizing magnetic activated sludge (MAS) was introduced to simplify process operations, as well as to enable excess sludge production to be controlled. Standard bench-scale experimental equipment and a few mobile pilot plants for the MAS process have been developed in the past few years. After developing a full-scale magnetic separator with a typical MAS suspension separation capacity of 200 m 3 d -1 , it became possible to design a full-scale plant and estimate the initial cost. It has been estimated that the total cost of the process (i.e., initial setup and operation) will result in savings, being less than that required for the conventional activated sludge process. It is possible that a new field of superconductive magnet applications can be developed if the MAS process is applied for large-scale wastewater treatment processes such as municipal sewage treatment.
{"title":"Characteristics of Magnetic Activated Sludge Process Utilizing Magnetic Separation and Social Implementation","authors":"Yasuzo Sakai","doi":"10.2221/jcsj.55.156","DOIUrl":"https://doi.org/10.2221/jcsj.55.156","url":null,"abstract":"Synopsis : To improve a biological wastewater process, magnetic separation was applied to a biological wastewater treatment process. An aerobic biological wastewater treatment process utilizing magnetic activated sludge (MAS) was introduced to simplify process operations, as well as to enable excess sludge production to be controlled. Standard bench-scale experimental equipment and a few mobile pilot plants for the MAS process have been developed in the past few years. After developing a full-scale magnetic separator with a typical MAS suspension separation capacity of 200 m 3 d -1 , it became possible to design a full-scale plant and estimate the initial cost. It has been estimated that the total cost of the process (i.e., initial setup and operation) will result in savings, being less than that required for the conventional activated sludge process. It is possible that a new field of superconductive magnet applications can be developed if the MAS process is applied for large-scale wastewater treatment processes such as municipal sewage treatment.","PeriodicalId":143949,"journal":{"name":"TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125355207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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