start-ver=1.4 cd-journal=joma no-vol=23 cd-vols= no-issue=1 article-no= start-page=380 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221229 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Thickness Measurement at High Lift-Off for Underwater Corroded Iron-Steel Structures Using a Magnetic Sensor Probe en-subtitle= kn-subtitle= en-abstract= kn-abstract=Infrastructure facilities that were built approximately half a century ago have rapidly aged. Steel sheet piles, the inspection object in this study, are severely corroded, resulting in cave-in damages at wharfs. To solve such a problem, non-destructive inspection techniques are required. We previously demonstrated plate thickness measurement using extremely low-frequency eddy current testing. However, when the steel sheet piles are located in water, shellfish adhere to their surface, causing a lift-off of several tens of millimeters. Therefore, this large lift-off hinders the thickness measurement owing to fluctuations of magnetic signals. In this study, sensor probes with different coil diameters were prototyped and the optimum size for measuring steel sheet piles at high lift-off was investigated. Using the probes, the magnetic field was applied with a lift-off range from 0 to 80 mm, and the intensity and phase of the detected magnetic field were analyzed. Subsequently, by increasing the probe diameter, a good sensitivity was obtained for the thickness estimation with a lift-off of up to 60 mm. Moreover, these probes were used to measure the thickness of actual steel sheet piles, and measurements were successfully obtained at a high lift-off. en-copyright= kn-copyright= en-aut-name=AdachiShoya en-aut-sei=Adachi en-aut-mei=Shoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HayashiMinoru en-aut-sei=Hayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakamiTaisei en-aut-sei=Kawakami en-aut-mei=Taisei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=AndoYuto en-aut-sei=Ando en-aut-mei=Yuto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=WangJin en-aut-sei=Wang en-aut-mei=Jin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=IshikawaToshiyuki en-aut-sei=Ishikawa en-aut-mei=Toshiyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=8 en-affil=Department of Civil, Environmental and Applied System Engineering, Faculty of Environmental and Urban Engineering, Kansai University kn-affil= affil-num=9 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= en-keyword=eddy current testing kn-keyword=eddy current testing en-keyword=high lift-off thickness measurement kn-keyword=high lift-off thickness measurement en-keyword=magnetic sensor kn-keyword=magnetic sensor en-keyword=corrosion kn-keyword=corrosion en-keyword=underwater steel structure kn-keyword=underwater steel structure END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=3 article-no= start-page=035109 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220303 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Magnetic thickness measurement for various iron steels using magnetic sensor and effect of electromagnetic characteristics en-subtitle= kn-subtitle= en-abstract= kn-abstract=The diagnosis and prevention of the deterioration of iron-steel infrastructure has become an important social issue in recent years. The thickness measurement technique (extremely low-frequency eddy current testing (ELECT)) using a magnetic sensor for detecting steel corrosion at extreme frequency ranges has been previously reported. Using the calibration curves based on the correlation between the phase of the detected magnetic signal and the plate thickness, the plate thickness reduction caused by corrosion can be estimated from the detected phase signal. Iron-steel materials have large changes in electromagnetic characteristics; therefore, the reference calibration data for each type of iron-steel are required for plate thickness estimation. In this study, the effect of electromagnetic characteristics on the magnetic thickness measurement was investigated to improve the thickness estimation. Four types of iron-steel plates (SS400, SM400A, SM490A, and SMA400AW) with thicknesses ranging from 1 mm to 18 mm were measured by ELECT, and the phase change at multiple frequencies of each plate were analyzed. The shift in the phase and linearity regions of the calibration curves for each type of steel plate was observed. To analyze this shift phenomenon, the electromagnetic characteristics (permeability mu and conductivity sigma) of each type of steel were measured. Compared with the permeability mu and conductivity sigma of each steel plate in the applied magnetic field strength range, the product (sigma mu) for various steel plates decreased in the following order: SM400 > SS400 >SMA400AW > SM490A. The product of mu and sigma is related to the skin depth, indicating the electromagnetic wave attenuation and eddy current phase shift in the material. Therefore, each shift in the calibration curve of each type of iron steel is explained by the changes in the parameters sigma and mu. en-copyright= kn-copyright= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HayashiMinoru en-aut-sei=Hayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawakamiTaisei en-aut-sei=Kawakami en-aut-mei=Taisei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=AdachiShoya en-aut-sei=Adachi en-aut-mei=Shoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=IshikawaToshiyuki en-aut-sei=Ishikawa en-aut-mei=Toshiyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=SaariMohd Mawardi en-aut-sei=Saari en-aut-mei=Mohd Mawardi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=HoriKengo en-aut-sei=Hori en-aut-mei=Kengo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=HisazumiKazumasa en-aut-sei=Hisazumi en-aut-mei=Kazumasa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=TominagaTomonori en-aut-sei=Tominaga en-aut-mei=Tomonori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Faculty of Environmental and Urban Engineering Department of Civil, Environmental and Applied System Engineering, Kansai University kn-affil= affil-num=8 en-affil=Faculty of Electrical and Electronic Engineering, Universiti Malaysia Pahang kn-affil= affil-num=9 en-affil=Nippon Steel Metal Products Co., Ltd. kn-affil= affil-num=10 en-affil=Nippon Steel Corp. kn-affil= affil-num=11 en-affil=Nippon Steel Corp. kn-affil= END start-ver=1.4 cd-journal=joma no-vol=10 cd-vols= no-issue=1 article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=202001 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Laser monitoring of dynamic behavior of magnetic nanoparticles in magnetic field gradient en-subtitle= kn-subtitle= en-abstract= kn-abstract=Manipulation of magnetic nanoparticles (MNP) by an external magnetic field has been widely studied in the fields of biotechnology and medicine for collecting and/or reacting biomaterials in the solutions. Here, dynamic behaviors of MNP in solution under changing gradient magnetic field were investigated using our newly developed laser transmission system (LTS) with a variable magnetic field manipulator. The manipulator consists of a moving permanent magnet placed beside the optical cell filled with MNP solution. A laser beam was focused on the cell and the transmitted laser beam was detected by a silicon photodiode, so that the localized concentration of the MNP at the focused area could be evaluated by the intensity of transmitted laser beam. In this study, the LTS was applied to evaluate dynamic behaviors of MNP in serum solution. Dispersion and aggregation of MNP in the solution were evaluated. While time evolution of dispersion depends on the serum concentration, the behavior during aggregation by the magnetic field was independent of the serum concentration. A series of measurements for zeta-potentials, distributions of particle size, and magnetization distributions was carried out to understand this difference in the behavior. The results indicated that a Brownian motion was main force to distribute the MNP in the solution; on the other hand, the magnetic force to the MNP mainly affected the behavior during aggregation of the MNP in the solution. en-copyright= kn-copyright= en-aut-name=TsunashimaKenta en-aut-sei=Tsunashima en-aut-mei=Kenta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=JinnoKatsuya en-aut-sei=Jinno en-aut-mei=Katsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HiramatsuBunta en-aut-sei=Hiramatsu en-aut-mei=Bunta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FujimotoKayo en-aut-sei=Fujimoto en-aut-mei=Kayo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SaariMohd Mawardi en-aut-sei=Saari en-aut-mei=Mohd Mawardi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Faculty of Electrical & Electronic Engineering, Universiti Malaysia Pahang kn-affil= affil-num=8 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=12 article-no= start-page=125317 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191220 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Magnetic characterization change by solvents of magnetic nanoparticles in liquid-phase magnetic immunoassay en-subtitle= kn-subtitle= en-abstract= kn-abstract=Liquid-phase magnetic immunoassay (MIA) using magnetic nano-particles (MNPs) has been studied as a more rapid method compared to optical methods for inspecting proteins and viruses. MIA can estimate the number of conjugated antibodies without being washed differently from conventional optical immunoassay. However, in the case of the liquid phase, it is considered that the magnetic properties of MNPs are affected by physical properties such as viscosity and impurity substances such as biological substances contained in the blood. In this study, the effect of sodium chloride (NaCl) in buffer and serum solution was evaluated to reveal the effect of serum because the sodium (Na+) and chloride (Cl-) ions in the serum dominate ion balance of blood. The measurement results of AC magnetic susceptibility and a dynamic light scattering (DLS) showed that the aggregation of MNPs was largely affected by the concentration of NaCl. This effect of the NaCl could be explained by shielding of the surface charge of MNPs by ions in the solution. Although the concentrations of NaCl in the buffer and serum solution were almost same, we found that MNPs were aggregated more in their size for those in the serum solution because of other impurities, such as proteins. These results suggest evaluation of effects of the contaminants in serum and optimization of polymer coatings of MNPs could be important factors to realize measurements of magnetic immunoassay with high accuracy. (C) 2019 Author(s). en-copyright= kn-copyright= en-aut-name=JinnoKatsuya en-aut-sei=Jinno en-aut-mei=Katsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HiramatsuBunta en-aut-sei=Hiramatsu en-aut-mei=Bunta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TsunashimaKenta en-aut-sei=Tsunashima en-aut-mei=Kenta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FujimotoKayo en-aut-sei=Fujimoto en-aut-mei=Kayo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SakaiKenji en-aut-sei=Sakai en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=133 cd-vols= no-issue=2 article-no= start-page=538 end-page=542 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=20080812 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Analysis of response mechanism of a proton-pumping gate FET hydrogen gas sensor in air en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Two different types of hydrogen response signals (DC and AC) of a proton-pumping gate FET with triple layer gate structure (Pd/proton conducting polymer/Pt) were obtained. The proton-pumping gate FET showed good selectivity against other gases (CH4, C2H6, NH3, and O2). For practical use, the hydrogen response characteristics of the proton-pumping gate FET were investigated in air (a gaseous mixture of oxygen and nitrogen). The proton-pumping gate FET showed different hydrogen response characteristics in nitrogen as well as in air, despite the lack of oxygen interference independently. To clarify the response mechanism of the proton-pumping gate FET, a hydrogen response measurement was performed, using a gas flow system and electrochemical impedance spectroscopy. Consequently, the difference in response between nitrogen and air was found to be due to the hydrogen dissociation reaction and the interference with the proton transfer caused by the adsorbed oxygen on the upper Pd gate electrode

en-copyright= kn-copyright= en-aut-name=YamaguchiTomiharu en-aut-sei=Yamaguchi en-aut-mei=Tomiharu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TakisawaMasanori en-aut-sei=Takisawa en-aut-mei=Masanori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KiwaToshihiko en-aut-sei=Kiwa en-aut-mei=Toshihiko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamadaHironobu en-aut-sei=Yamada en-aut-mei=Hironobu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TsukadaKeiji en-aut-sei=Tsukada en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Okayama University affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Okayama University affil-num=5 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Okayama University en-keyword=Field effect transistor (FET) kn-keyword=Field effect transistor (FET) en-keyword=Hydrogen sensor kn-keyword=Hydrogen sensor en-keyword=Proton-pumping gate kn-keyword=Proton-pumping gate en-keyword=Oxygen kn-keyword=Oxygen en-keyword=Electrochemical impedance spectroscopy (EIS) kn-keyword=Electrochemical impedance spectroscopy (EIS) END