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Determination of aniline derivatives in water samples after preconcentration with oxidized multiwalled carbon nanotubes as solid-phase extraction disk

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Frontiers of Chemical Science and Engineering 2012年第3期6卷 270-275页

作者： Hideyuki KATSUMATA Yuta ODA Satoshi KANECO Tohru SUZUKI kiyohisa ohta Department of Chemistry for Materials Graduate School of Engineering Mie University Tsu 514-8507 Japan Environmental Preservation Center Mie University Tsu 514-8507 Japan

A sensitive and selective preconcentration method using solid-phase extraction （SPE） disk made from oxidized multiwalled carbon nanotubes （OMWCNTs）, has been developed for the determination of aniline derivatives, such as 2-nitroaniline （2-NA）, 4- nitroaniline （4-NA）, and 2,4-dichloroaniline （2,4-DCA） in water samples. Anilines were extracted onto OMWCNT disk and then determined by high performance liquid chromatography （HPLC） with UV detector. Several parameters on the recovery of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 8 using 200 mL of validation solution containing 2 ug of anilines and 10 mL of acetonitrile/ethanol （8/2, v/v） as an eluent. Relative standard deviations for five determinations were 7.5% （2-NA）, 6.5% （4-NA） and 3.8% （2,4-DCA） under optimum conditions. The linear range of calibration curves were 0.5 ng.mL 1 to 15 ng.mL-1 for each analyte with good correlation coefficients. The detection limits （3S/N） of 2-NA, 4-NA and 31 pg.mL -1 and 26 pg.mL-1 was successfully applied to 2,4-DCA were 30pg.mL -1, respectively. Our method the determination of aniline compounds in fiver water sample with high precision and accuracy.

关键词： aniline determination solid-phase extraction,oxidized multiwalled carbon nanotubes water sample,HPLC-UV

Simultaneous removal of trihalomethanes by bimetallic Ag/Zn:kinetics study

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Frontiers of Chemical Science and Engineering 2010年第3期4卷 322-327页

作者： Ahmed H A DABWAN Satoshi KANECO Hideyuki KATSUMATA Tohru SUZUKI Kiyoyuki EGUSA kiyohisa ohta Faculty of Chemical Engineering Technology Tati University CollegeJalan PanchorTeluk Kalong24000 KemamanTerengganuMalaysia Department of Chemistry for Materials Graduate School of EngineeringMie UniversityMie 514-8507Japan Environmental Preservation Center Mie UniversityMie 514-8507Japan

In the present work,bimetallic silver/zinc was applied into the degradation of trihalomethanes,THMs:CHCl_(3),CHBrCl_(2),CHBr_(2)Cl,and CHBr_(3).The kinetics reaction rates and removal efficiencies of the THM compound mixtures,in the aqueous solutions,were investigated.Batch experiments were conducted under mild conditions,ambient temperature,and pressure.The primary degradation reaction followed a pseudo-first-order kinetic law.The first-order rate constants and the degradation efficiencies followed the decreasing order of CHBr_(3)>CHBr_(2)Cl>CHBrCl_(2)>CHCl_(3).The bond dissociation energy and hydrophilic/hydrophobic characteristics of the THM compounds may become the most important parameters affecting the degradation kinetics and efficiency by bimetallic Ag/Zn.

关键词： degradation trihalomethanes bimetallic silver/zinc halogenated pollutants kinetics

Water purification with sintered porous materials fabricated at 400℃ from sea bottom sediments

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Journal of Environmental Sciences 2008年第2期20卷 172-176页

作者： DABWAN Ahmed H A IMAI Daizo KANECO Satoshi SENMATSU Isamu NAKAHAMA Katsuyuki KATSUMATA Hideyuki SUZUKI Tohru ohta kiyohisa Mie Industry and Enterprise Support Center ShimaMie 517-0501Japan Mie Industry and Enterprise Support Center ShimaMie 517-0501Japan Department of Chemistry for MaterialsGraduate School of EngineeringMie UniversityMie 514-8507Japan. Department of Chemistry for Materials Graduate School of EngineeringMie UniversityMie 514-8507Japan. Environmental Preservation Center Mie UniversityMie 514-8507Japan Department of Chemistry for Materials Graduate School of EngineeringMie UniversityMie 514-8507Japan. Environmental Preservation CenterMie UniversityMie 514-8507Japan

A sintering technology for preparing porous materials from sea bottom sediments was developed for use in water purification. The purpose of the present study was to develop methods for converting the sea bottom sediments dredged from Ago Bay into value-added recycled products. The sintered products fabricated at 400℃ were found to be very effective adsorbents for the removal of heavy metals.

关键词： sintering preparation technology porous materials sea bottom sediments water purification heavy metals

The deterministic condition for the ground reaction force acting point on the combined knee valgus and tibial internal rotation moments in early phase of cutting maneuvers in female athletes

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Journal of Sport and Health Science 2024年第3期13卷 376-386页

作者： Issei Ogasawara Ken ohta Gajanan S.Revankar Shoji Konda Yohei Shimokochi Hideyuki Koga Ken Nakata Department of Health and Sport Sciences Graduate School of MedicineOsaka UniversityToyonaka 560-0043Japan Sports Sensing Co. LTD.Fukuoka 815-0035Japan Department of Neurology Graduate School of MedicineOsaka UniversitySuita 565-0871Japan Department of Health and Sport Management Osaka University of Health and Sport SciencesSennan-gun 590-0496Japan Department of Joint Surgery and Sports Medicine Graduate School of Medical and Dental SciencesTokyo Medical and Dental UniversityBunkyo-ku 113-8519Japan

Background:Combined knee valgus and tibial internal rotation(VL+IR)moments have been shown to stress the anterior cruciate ligament(ACL)in several in vitro cadaveric studies.To utilize this knowledge for non-contact ACL injury prevention in sports,it is necessary to elucidate how the ground reaction force(GRF)acting point(center of pressure(CoP))in the stance foot produces combined knee VL+IR moments in risky maneuvers,such as cuttings.However,the effects of the GRF acting point on the development of the combined knee VL+IR moment in cutting are still unknown.Methods:We first established the deterministic mechanical condition that the CoP position relative to the tibial rotational axis differentiates the GRF vector’s directional probability for developing the combined knee VL+IR moment,and theoretically predicted that when the CoP is posterior to the tibial rotational axis,the GRF vector is more likely to produce the combined knee VL+IR moment than when the CoP is anterior to the tibial rotational axis.Then,we tested a stochastic aspect of our theory in a lab-controlled in vivo experiment.Fourteen females performed 60˚cutting under forefoot/rearfoot strike conditions(10 trials each).The positions of lower limb markers and GRF data were measured,and the knee moment due to GRF vector was calculated.The trials were divided into anterior-and posterior-CoP groups depending on the CoP position relative to the tibial rotational axis at each 10 ms interval from 0 to 100 ms after foot strike,and the occurrence rate of the combined knee VL+IR moment was compared between trial groups.Results:The posterior-CoP group showed significantly higher occurrence rates of the combined knee VL+IR moment(maximum of 82.8%)at every time point than those of the anterior-CoP trials,as theoretically predicted by the deterministic mechanical condition.Conclusion:The rearfoot strikes inducing the posterior CoP should be avoided to reduce the risk of non-contact ACL injury associated with the combined knee VL+IR stress.

关键词： Center of pressure Deterministic condition Foot strike pattern Injury mechanism Moment of ground reaction force

Behavior of Vaneless Diffuser Stall in a Centrifugal Compressor

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Journal of Thermal Science 2022年第1期31卷 3-12页

作者： AGARI Yuki YAMAO Yoshifumi FUJISAWA Nobumichi ohta Yutaka Department of Applied Mechanics and Aerospace Engineering Waseda UniversityTokyo 169-8555Japan

The rotating stall in a centrifugal compressor with a vaneless diffuser was investigated both experimentally and numerically with focus on the effect of the internal flow field within the impeller on the diffuser stall.Through numerical analysis,the boundary layer separation at the impeller outlet was found to play an important role in the expansion and rotation processes of the diffuser stall.In particular,the expanded boundary layer separation near the hub side at the outlet of the main blade(M.B.)suction surface passage was considered to be the main cause of the expansion and rotation processes.A longitudinal vortex existed at the throat of the M.B.passage,and the mass flow rate in the M.B.passage was significantly reduced by the blockage effect.In addition,the longitudinal vortex induced the rolling up flow near the hub side at the impeller exit.Thus,the boundary layer separation expanded.

关键词： centrifugal compressor vaneless diffuser pressure and velocity measurement CFD rotating stall

The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

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National Science Review 2021年第4期8卷 18-20页

作者： Kenji ohta Kei Hirose Department of Earth and Planetary Sciences Tokyo Institute of Technology Earth-Life Science Institute Tokyo Institute of Technology Department of Earth and Planetary Science The University of Tokyo

The thermal conductivity of iron alloys is a key to understanding the mechanism of convection in the Earth’s liquid core and its thermal history. The Earth’s magnetic field is formed by a dynamo action that requires... 详细信息

关键词： ELECTRICAL-RESISTIVITY HIGH-PRESSURE IRON ALLOYS SI NI

Unsteady Behavior and Control of Vortices in Centrifugal Compressor

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Journal of Thermal Science 2014年第5期23卷 401-411页

作者： Yutaka ohta Nobumichi Fujisawa Department of Applied Mechanics and Aerospace Engineering Waseda University3-4-1OkuboShinjukuTokyo169-8555Japan Graduate School of Fundamental Science and Engineering Waseda University3-4-1OkuboShinjukuTokyo169-8555Japan

Two examples of the use of vortex control to reduce noise and enhance the stable operating range of a centrifugal compressor are presented in this paper.In the case of high-flow operation of a centrifugal compressor with a vaned diffuser,a discrete frequency noise induced by interaction between the impeller-discharge flow and the diffuser vane,which appears most notably in the power spectra of the radiated noise,can be reduced using a tapered diffuser vane(TDV) without affecting the performance of the compressor.Twin longitudinal vortices produced by leakage flow passing through the tapered portion of the diffuser vane induce secondary flow in the direction of the blade surface and prevent flow separation from the leading edge of the diffuser.The use of a TDV can effectively reduce both the discrete frequency noise generated by the interaction between the impeller-discharge flow and the diffuser surface and the broadband turbulent noise component.In the case of low-flow operation,a leading-edge vortex(LEV) that forms on the shroud side of the suction surface near the leading edge of the diffuser increases significantly in size and blocks flow in the diffuser passage.The formation of an LEV may adversely affect the performance of the compressor and may cause the diffuser to stall.Using a one-side tapered diffuser vane to suppress the evolution of an LEV,the stable operating range of the compressor can be increased by more than 12 percent,and the pressure-rise characteristics of the compressor can be improved.The results of a supplementary examination of the structure and unsteady behavior of LEVs,conducted by means of detailed numerical simulations,are also presented.

关键词：压缩机控制不稳定离心式行为涡流叶片表面扩散器离散频率

Coexisting State of Surge and Rotating Stall in a Two-Stage Axial Flow Com-pressor using a Double-Phase-Locked Averaging Technique

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Journal of Thermal Science 2017年第1期26卷 38-46页

作者： Yuu SAKATA Yutaka ohta Graduate school of Fundamental Science and Engineering Waseda University 3-4-10kuboShinjuku Tokyo 169-8555 Japan. Department of Applied Mechanics and Aerospace Engineering Waseda University 3-4-10kubo Shinjuku Tokyo169-8555 Japan.

The interaction between surge and rotating stall in an axial flow compressor was investigated from the viewpoint of an unsteady inner flow structure. The aim of this study was to identify the key factor that determines the switching phenomenon of a surge cycle. The main feature of the tested compressor is a shock tube connected in series to the compressor outlet through a diaphragm, slits, and a concentric duplex pipe: this system allows surge and rotating stall to be generated by connecting the shock tube with the compressor, or enables the compression plane wave injection. The unsteady characteristics and the internal flow velocity fluctuations were measured in detail, and the stall cell structure was averaged and visualized along the movement of the operation point under a coexisting state of surge. A coefficient of the cell scale fluctuation was calculated using the result of the averaging, and it confirmed that the processes of inner flow structure change differed from each other according to the next cycle of the surge. The result suggests that the key factor that determines the next cycle is the transformation of the internal flow structure, particularly between the stall cell and the entire circumferential stall, in both the recovering and stalling processes.

关键词： Axial flow compressor, Rotating stall, Surge, Double-phase-locked measurement, Compression wave.

Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography

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World Journal of Gastroenterology 2012年第43期18卷 6269-6276页

作者： Akihiro Tateyama Yoshihiko Fukukura Koji Takumi Toshikazu Shindo Yuichi Kumagae kiyohisa Kamimura Masayuki Nakajo Department of Radiology Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima 890-8544 Japan

AIM:To clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT). METHODS:Twenty-six patients with 61 hepatic hem- angiomas who underwent both Gd-EOB-DTPA-enhanced MRI and enhanced CT were retrospectively reviewed. Hemangioma appearances (presence of peripheral nodular enhancement, central nodular enhancement, diffuse homogenous enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and prolonged enhancement during the equilibrium phase) on Gd-EOB-DTPA-enhanced MRI and enhanced CT were evaluated.The degree of contrast enhancement at the enhancing portion within the hemangioma was visually assessed using a five-point scale during each phase. For quantitative analysis, the tumor-muscle signal intensity ratio (SIR), the liver-muscle SIR, and the attenuation value of the tumor and liver parenchyma were calculated. The McNemar test and the Wilcoxon's signed rank test were used to assess the significance of differences in the appearances of hemangiomas and in the visual grade of tumor contrast enhancement between Gd-EOB-DTPA-enhanced MRI and enhanced CT. RESULTS:There was no significant difference between Gd-EOB-DTPA-enhanced MRI and enhanced CT in the presence of peripheral nodular enhancement (85% vs 82%), central nodular enhancement (3% vs 3%), diffuse enhancement (11% vs 16%), or arterioportal shunt (23% vs 34%) during arterial phase, or fill-in enhancement (79% vs 80%) during portal venous phase. Prolonged enhancement during equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than on enhanced CT (52% vs 100%, P < 0.001). On visual inspection, there was significantly less contrast enhancement of the enhancing portion on Gd-EOB-DTPA-enhanced MRI than on enhanced CT during the arterial (3.94 ± 0.98 vs 4.57 ± 0.64, respectively, P < 0.001), portal venous (3.72 ± 0.82 vs 4.36 ± 0.53, respecti

关键词：磁共振成像肝脏血管计算机断层扫描影像学平衡阶段强化处理恶性肿瘤