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  2. 武居 昌宏

武居 昌宏

タケイ マサヒロ  (Masahiro Takei)

基本情報

所属
千葉大学 大学院工学研究院総合工学講座 教授
学位
博士(工学)(1995年3月 早稲田大学)
ORCID ID
 https://orcid.org/0000-0003-3855-7202
J-GLOBAL ID
200901064060287550
researchmap会員ID
1000182863
外部リンク

研究キーワード

 7

研究分野

 1

経歴

 6
もっとみる

学歴

 2

委員歴

 19
もっとみる

受賞

 18
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論文

 358
  • M Kimura, M Takei, Y Saito, A Saima
    JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME 127(5) 1047-1050 2005年9月  
    The present paper describes the application of discrete wavelet transform to the analysis of condensation jets in order to clarify the fluid and heat transfer phenomenon. The condensation jets in the nozzle vicinity are experimentally visualized via the laser light sheet method to obtain condensation particle density images of the jets. The image of the condensation particle density in the jet is decomposed to mean and fluctuation images via wavelet multiresolution. The dominant temperature boundary and the mean component outside the boundary were obtained from wavelet separation images. The boundary was compared to the experimentally obtained temperature distribution.
  • 武居 昌宏
    混相流 19(3) 232-239 2005年9月  
  • 武居 昌宏
    粉体工学会誌 = Journal of the Society of Powder Technology, Japan 42(4) 257-264 2005年4月10日  
  • 新井田 直樹, 島田 道男, 星野 邦広, 原 正一, 武居 昌宏
    可視化情報学会誌. Suppl. 25(1) 375-378 2005年3月15日  
    A detecting method on quantity and oil existence in a model tank using ultrasonic pulse echo method have been assuming the remained oil inside sunken ships C scope which is one of the method of the pulse-echo method was used for the construction of image. This experiment showed that the measurement of the remained oil inside the sunken ship was possible using ultrasomcpulse echo. The goal of thisreseamh will be the establishment of this technology to can measure remained oil inside sunken ships quantitatively and three-dimensionally by tomography-method using many measuring points.
  • Masahiro Takei, Mitsuaki Ochi, Kiyoshi Horii
    4th World Congress in Industrial Process Tomography 726-731 2005年  
    A new reconstruction method called Generalized Vector Sampled Pattern Matching (GVSPM) has been applied to an ill-posed inverse problem involving an electrical capacitance CT for solid air twophase flow. This new method is able to achieve stable convergence without the use of an empirical value. This accurate reconstruction is accomplished using an objective function that is calculated as the inner product calculation between the experimental capacitance and the reconstructed image capacitance. The GVSPM method is compared with the conventional Landweber (LW) and Iterative Tikhonov regularization (ITR) methods in terms of capacitance residual, image error and image correlation. Overall, the accuracy is strongly dependent upon the image type and the iteration number, however the GVSPM method proved superior to the LW and the ITR methods in the case of annular pseudo particle images.
  • 田中 健嗣, 吉田 美智子, 都 徳照, 植村 知正, 武居 昌宏
    年次大会講演論文集 2005 221-222 2005年  
    Two kinds of swirling flow are generated in a main vertical pipe by using two kinds of air inlets. A rod-like material is put into the main vertical pipe. Four optical sensors are attached to the main vertical pipe. When the rod-like material is sensed by the four optical sensors, laser sheet is irradiated and the image is obtained by 3D-PIV. It means the posture of the rod-like material is upright and rotating with orientation. However, when the rod-like material is sensed by the two optical sensors, it means the posture of the rod-like material is not upright and rotating without orientation. Two images obtained by the above-mentioned were compared to derive the condition for the rod-like material to rotate at the constant height in the main vertical pipe, and the flow field around the rod-like material is analyzed.
  • 田中 健嗣, 吉田 美智子, 都 徳照, 植村 知正, 武居 昌宏
    可視化情報学会誌 25(2) 295-298 2005年  
    Two kinds of swirling flow are generated in a main vertical pipe by using two kinds of air inlets. A rod-like material is put into the main vertical pipe. Four optical sensors are attached to the main vertical pipe. When the rod-like material is sensed by the four optical sensors, laser sheet is irradiated and the image is obtained by 3D-PIV. It means the posture of the rod-like material is upright and rotating with orientation. However, when the rod-like material is sensed by the two optical sensors, it means the posture of the rod-like material is not upright and rotating without orientation. Two images obtained by the above-mentioned were compared to derive the condition for the rod-like material to rotate at the constant height in the main vertical pipe, and the flow field around the rod-like material is analyzed by modal wavelet transform.
  • DH Doh, HJ Jo, TG Hwang, JH Choi, KR Cho, K Tanaka, M Takei
    PROCEEDINGS OF THE FIFTEENTH (2005) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL 2 123-129 2005年  査読有り
    A simultaneous measurement system that can analyze the flow-structure interactions is constructed. The system consists of four CCD cameras, two for capturing instantaneous flow fields and two for tracking a solid body. The three-dimensional vector fields around a floating body are measured with a 3D-PTV technique while the motion of the cylinder forced by the flow field is measured simultaneously with a motion tracking technique. A floating solid body (circular cylinder) suspended in working fluid is the target of the measurement. A conditional sampling concept is introduced into the measurement system. The interaction between the flow motion and the solid body motion is analyzed quantitatively with the constructed system.
  • 武居 昌宏, 武居昌宏, 斎藤兆古
    日本機械学会論文集B編 71(703) 745-752 2005年  
  • 武居 昌宏, M. Takei, M. Ochi, Y. Saito, K. Horii
    日本機械学会英文論文集 47(2) 369-377 2004年5月  
  • 武居 昌宏, M. TAKEI, M. OCHI, Y. SAITO
    パウダーテクノロジー エルセビア・サイエンス 142(1) 70-78 2004年4月  
  • 田中 健嗣, 吉田 美智子, 都 徳照, 植村 知正, 武居 昌宏
    可視化情報学会誌 24(2) 13-14 2004年  
    Velocity of swirling flow has been measured by 3D-PIV to analyze the frequency patterns of the azimuthal velocity with modal wavelet image processing. The swirling flows are two types, one inlet and four inlets around a vertical pipe. As a result, the wavelet levels at middle and high frequency of four inlets type are lower than that of the one inlet type. It means four inlet types has a possibility that a rod-like material would be conveyed with an orientation in swirling flow experientially.
  • 山崎 照佳, 武居 昌宏, 斎藤 兆古, 堀井 清之
    可視化情報学会誌 24(1) 77-78 2004年  
    This study proposes a novel image processing for PIV images which is called a modal wavelet transform. In this study, green function type of modal wavelet transform has the analysis as well as Dirichlet type and Neumann type. Green function type of modal wavelet transform has high performance in the same way as Neumann type of modal wavelet transform for image correlation of a PIV image.
  • 武居 昌宏, M. TAKEI, Y. SAITO
    メジャーメント・サイエンス・テクノロジー 物理協会 15 1371-1381 2004年  
  • 武居 昌宏, H.Li, M.Takei, Y.Tomita, Y. Saito, K.Horii
    Particulate Science and Technology: An International Journal, Taylor & Francis 22(2) 107-118 2004年  
  • 武居 昌宏, N.Kasagi, M.Takei
    可視化情報学会英文誌 7(4) 265 2004年  
  • 山崎照佳
    日本機械学会第16回計算力学講演会, (2003) 105-106 2003年11月  
  • 辻野 真也, 武居 昌宏, 越智 光昭
    可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan 23(2) 215-216 2003年10月15日  
    Void fraction of solid-gas two phase flow in a horizontal pipe has been measured using capacitance CT. It was confirmed that the relation between the void fraction and flow pattern from the experiments that made flow velocity and particle height of an initial accumulation bed the parameter. As a result, the flow pattern was classified three kinds.
  • 山崎 照佳, 武居 昌宏, 越智 光昭, 李 輝, 斎藤 兆古, 堀井 清之
    可視化情報学会誌. Suppl. 23(1) 81-82 2003年7月1日  
  • 武居 昌宏, 斎藤 兆古, 堀井 清之
    可視化情報学会誌. Suppl. 23(1) 167-168 2003年7月1日  
  • 武居 昌宏
    噴流工学 20(2) 32-41 2003年6月  
  • 武居 昌宏, 李 輝, 越智 光昭, 斎藤 兆古, 堀井 清之
    混相流 17(1) 29-36 2003年3月15日  
  • Masahiro Takei, Hui Li, Mitsuaki Ochi, Yoshifuru Saito, Kiyoshi Horii
    3rd World Congress on Industrial Process Tomography 528-534 2003年  
    A new reconstruction method, which is called Generalized Vector Sampled Pattern Matching (GVSPM) method, has been applied to an ill-posed inverse problem of a capacitance-computed tomography for solid air two-phase flow. In pseudo two-phase flow images, the correlation of the reconstructed images by GVSPM is higher than those by a conventional Landweber (LW) iterative method by 32.5%. Moreover, in solid air two-phase flow images, the deviation between the particles void fraction by experimental capacitance and that by the reconstruction methods is calculated. As a result, the void fraction deviation of GVSPM reconstructed image is lower than that of LW by 56.7%. Also, the time-mean correlation between the experimental capacitance and the capacitances from the reconstruction method is calculated. As a result, GVSPM method improves the correlation by 23.6% as compared with LW method. The accurate reconstruction of GVSPM results from an inner product calculation between the experimental capacitance and the capacitance from the reconstructed images as an objective function.
  • Masahiro Takei, Mitsuaki Ochi, Yoshifuru Saito, Kiyoshi Horii
    Proceedings of the ASME/JSME Joint Fluids Engineering Conference 2 2321-2327 2003年  
    Spatial particle density distribution images in a pipe cross section have been evaluated by means of state transition matrix, which is a parameter indicating the dominant particle density transition patterns among time series images consisting of CT 2D-space and ID-time. State transition characterizes the transition patterns for positions in a cross section as monotonous transitions, sudden transitions, and extreme value transitions. In free fall particles in a vertical pipe, high, sudden and extreme value transitions do not occur, because particle flow rate at this position is low, and therefore the probability of collision among particles is also low. A high, sudden and extreme value transitions occur near the pipe center when the particle flow rate is high, because the probability of collision among particles is high.
  • Mitsuaki Ochi, Hiroshi Nishimura, Masahiro Takei
    Proceedings of the ASME/JSME Joint Fluids Engineering Conference 2 455-460 2003年  
    A simple empirical equation of the minimum transport velocity of a dilute two-phase flow for granular solids in a vertical pipe has been derived on the basis of both a dynamic model equation and the transport experiment. The minimum transport velocity means here the limiting air velocity at which conveying is possible in a state in which particles are not stagnant or recircular in the pipe. As a result, it is found that the empirical equation of the minimum transport velocity, simply called the minimum velocity, can arrange the data of this study with a pretty good accuracy.
  • Masahiro Takei, Hui Li, Mitsuaki Ochi, Yoshifuru Saito, Kiyoshi Horii
    Proceedings of the ASME Fluids Engineering Division Summer Meeting 2 429-435 2003年  
    A new concept, which estimates inversely two kinds of potential distributions from particle velocity distribution by means of least norm method, has been launched. This concept is applied to estimating particle movement in spiral flow. Also, the reliability of the concept is discussed by wavelets filter. As a result, the vector potential has high plus value near the center on a pipe cross-section, and high minus value near the wall. The high plus potential is caused by regular movement of particle. The high minus potential is caused by the irregular movement due to the collision to the pipe wall. Also, the scalar potential is randomly appeared at the whole position, which is caused by the irregular movement due to collision between particles. From Helmholtz's theorem, general velocity v consists of rotation component from vector potential V and divergent component from scalar potential φ as v = rotV - grad φ. The estimate of the potentials from the particle velocity is an ill-posed inverse problem.
  • 木村 元昭, 武居 昌宏, 斎藤 兆古, 堀井 清之, 斎間 厚
    可視化情報学会論文集 23(2) 9-16 2003年  
    本研究では，冷却乾燥空気が円形ノズルより高湿度雰囲気に噴出されたとき，ノズル近傍より発生する凝縮粒子の2次元画像を，離散ウェーブレット多重解像度に分解し，その凝縮粒子濃度の平均値成分と変動値成分との分離を行い，凝縮構造のより詳細な可視化を行うことを目的としている．さらに，凝縮噴流温度分布を考察することにより，その妥当性の検討を行うことも目的としている．冷却乾燥空気を円形ノズルより高湿度雰囲気に噴出し，1.0秒間露光した凝縮噴流の二次元画像を，ウェーブレット多重解像度に分解し，ウェーブレットレベルの0と1との低レベル和を，凝縮粒子発生率の平均値成分とし，ウェーブレットレベルの2から6までの高レベル和を，凝縮粒子発生率の変動成分とした．その結果次のことが明らかとなった．(1)平均値成分と変動値成分とが混在した凝縮噴流の二次元画像から，平均値成分画像と変動値成分画像とに分離することができた．(2)分離された変動値成分画像から温度支配境界位置を求め，その位置が露点温度に達した半径位置(露点位置)よりも外側に位置し，平均温度分布が噴流中央部温度から周囲温度に到る半径位置(周囲温度到達位置)よりも内側に位置した．これは，自由せん断層内で生じる組織的構造による間欠的流れの変動が存在し，露点位置より外側でも，間欠的に露点温度以下に達し凝縮粒子が生じたからである．(3)分離された平均値画像から得られた平均成分最外周位置は，ノズル近傍では周囲温度到達位置とほぼ同じ位置であるが，より下流側では，平均成分最外周位置は周囲温度到達位置の外側に位置した．これは，周囲温度到達位置より外側では，その場所における凝縮粒子の生成はありえないが，より下流側では上流で発生した凝縮粒子が自由噴流内の渦構造に誘導され，その下流において外周部に輸送された結果，その凝縮粒子の画像が凝縮粒子の流跡線として記録されたからである．
  • 武居 昌宏, 横山さかり, 李和樹, 山田高三, 武居昌宏, 斉藤兆古
    砥粒加工学会（砥粒加工学会誌） 47(10) 30-33 2003年  
  • 武居 昌宏, Suzuki, M.Takei
    可視化情報学会英文誌 6(4) 321 2003年  
  • 武居 昌宏, M.Kimura, M.Takei, C.Ho, Y.Saito, K.,Horii
    米国機械学会 流体工学雑誌 124(4) 1018-1024 2002年12月  
  • 武居 昌宏, 越智 光昭, 斎藤 兆古
    噴流工学 19(2) 4-11 2002年7月  
  • Masahiro Takei, Mitsuaki Ochi, Hui Li, Yoshifuru Saito, Kiyoshi Horii
    Journal of Flow Visualization and Image Processing 9(4) 271-280 2002年  
    Particle distributions in a cross section of a solid-air two-phase flow through a pipe are visualized by capacitance CT at a frame rate of 100 fps. The CT images are decomposed by the discrete wavelet transform, and the image correlation between the time-series image and a standard choking image. The correlation coefficient on wavelet 0 at a choking state is close to 1.0. The level-0 wavelet transformation resolves the largest particle distribution features. This technique is expected to be useful as a basis for automatically judging block-age emergencies in airborne particle transport through pipelines.
  • 武居 昌宏, 李 輝, 越智 光昭, 斎藤 兆古, 堀井 清之
    可視化情報学会論文集 22(5) 36-43 2002年  
    キャパシタンスCTとウェーブレット多重解像度を用いた管路内固気二相流における二次元粒子分布の特徴抽出方法を提案した.実験は,キャパシタンスCTを用いて,模擬障害物直後の管路内固気二相流のキャパシタンスを測定し,10ms間隔で500ms間,連続50フレームの二次元誘電率分布画像を得た.管路内の気流のレイノルズ数は4.71×104で,固気質量比Mtは6.24と16.7であった.その開放面積比を変化させた障害物直後の管路内固気二相流の流動状態のCT画像に対して,離散ウェーブレット多重解像度を施し,支配的な二次元粒子分布を抽出した.その結果,開放面積比がやや小さい場合には,開放面積比に依存するウェーブレットレベルよりも高い二次的支配レベルに,粒子濃度の大きな値が見られた.この二次的支配レベルは,粒子間および粒子と管壁との衝突によって起こる濃度むら現象の影響であると考えられる.
  • 武居 昌宏, 李 輝, 越智 光昭, 斎藤 兆古, 堀井 清之
    可視化情報学会論文集 22(9) 71-78 2002年  
    固気二相流キャパシタンスCTの不適切逆問題の解法に, サンプルドパターン・マッチング(SPM)法を適用した. その結論, 模擬画像を用いたシミュレーションでは, SPM法は再構成画像の精度を向上させた. 具体的には, 粒子が管路断面中心に位置する画像, 管底に位置する画像, および, 分散している画像について, SPM法はNR(Newton-Raphson)法と比較して平均画像相関で32. 5%増加し, LBP(Linear Back Projection)法と比較して65. 0% 増加した. また, 再構成画像から求めたボイド率とキャパシタンスから求めたボイド率の時間平均偏差を計算した. その結果, SPM法は0. 749で, NR法の1. 73よりも, 56. 7%低下させることができた. これはSPM法の再構成画像の粒子分布がより精度が高いことを意味する. さらに, SPM法による再構成画像からのキャパシタンスと実験キャパシタンス間の時間平均相関 は0. 970であったが, LBP法とNR法のそれは非常に小さかった. 具体的には, SPM法はNR法と比較して, キャパシタンスの時間相関を23. 6%増加させた. それは, SPM法は評価関数をもち, C´ (0)とC´ (k)の内積を1. 0に近づけるからである.
  • 武居 昌宏, M.Takei, H.Li, M.Ochi, Y.Saito, K.Horii
    日本AEM学会英文誌 IOS Press 15 423-430 2002年  
  • 武居 昌宏, H.Li, M.Takei, Y.Saito, K.Horii
    日本AEM学会英文誌 IOS Press 15 383-392 2002年  
  • 武居 昌宏, H.Li Yu.Zhou, M.Takei, Y.Saito, K.Horii
    日本AEM学会英文誌 IOS Press 15 393-402 2002年  
  • 武居 昌宏, M.Takei, M.Ochi, Y.Saito, K.Horii
    Particulate Science and Technology an International Journal, Published by Taylor & Francis 20(4) 341-354 2002年  
  • 武居 昌宏, M.Takei, H.Li, M.Ochi, Y.Saito, K.Horii
    米国可視化流体工学会学会誌 9(4) 271-351 2002年  
  • 西村 浩, 越智 光昭, 武居 昌宏, 菅谷 貴俊
    混相流 = Japanese journal of multiphase flow 15(4) 423-431 2001年12月15日  
  • 武居 昌宏, H. Li, M. Takei, Y.Saito, K. Horii
    日本航空宇宙学会英文誌 43(142) 203-207 2001年2月  
  • Motoaki Kimura, Masahiro Takei, Atushi Saima, Karen Vierow, Yoshifuru Saito, Kiyoshi Horii
    Journal of Flow Visualization and Image Processing 8(2-3) 149-164 2001年  
    This paper describes the application of discrete wavelet transforms to the analysis of condensation jets in order to clarify the associated fluid and heat transfer phenomena. An experimentally obtained, two-dimensional image of the condensation particle density around the jet was decomposed into seven levels of resolution with their respective wavelengths. Based on the known physical characteristics of turbulent flow around the jet, levels 0 and 1 were shown to represent the steady components of the condensation particle density, and the higher levels represent the fluctuating components. From the analysis images, the width of the condensation zone was obtained and this compared well with the width inferred from temperature measurements. Thus, the method was verified and also provided data not available experimentally.
  • Hui Li, Yu Zhou, Masahiro Takei, Yoshifuru Saito, Kiyoshi Horii
    International Journal of Applied Electromagnetics and Mechanics 15(1-4) 393-402 2001年  
    The vector wavelet multi-resolution technique based on the orthogonal wavelet transform was used to analyze the velocity vector data that were simultaneously obtained by sixteen X-wires in the turbulent near-wake of a circular cylinder at different streamwise positions. The instantaneous velocity vector field is decomposed into the multi-scale structures, and its sectional streamline of various scales is displayed. The large-scale structures in the plane of mean shear are consistent with the well-known Kármán vortices. The structures that correspond to the saddle region between Kármán vortices are identified with the rib-like structures. Even smaller scale structures are also observed. As increasing x/d, the decay of vortical structure and rib-like structure are observed. The topologies of Reynolds stress and RMS vorticity associated with the multi-scale structures are discussed at different downstream positions. It is found that the most significant contribution to Reynolds stress comes from the frequency components of f ≤ 219 Hz at x/d = 20. However, the contribution to Reynolds stress coming from the intermediate-scale structure becomes weak at x/d = 40. The RMS vorticity components of f = 875 Hz is the largest among all components.
  • Masahiro Takei, Hui Li, Mitsuaki Ochi, Yoshifuru Saito, Kiyoshi Horii
    International Journal of Applied Electromagnetics and Mechanics 15(1-4) 423-430 2001年  
    A concept to extract a feature of solid-air two-phase flow in a pipeline has been launched with a combination of a capacitance-computed tomography and wavelets transform. With this concept, particle distribution images obtained by CT are transformed with discrete wavelets multiresolution. As a result, in the case of low open area ratios of the pipe cross-section, high particle densities are shown in secondary dominant levels as well as a substantial space level. The high value in the secondary level resulted from inhomogeneous density due to collision between particles.
  • Hui Li, Masahiro Takei, Yoshifuru Saito, Kiyoshi Horii
    International Journal of Applied Electromagnetics and Mechanics 15(1-4) 383-392 2001年  
    Our motive of this study is to develop an application of the wavelet packet to PIV image compression processing in order to improve the spatial resolution and reliability furthermore. It was found that the reconstructed PIV image with a lower compression ratio might emphasize particle edges at a relatively high spatial resolution. The reconstructed PIV image with a higher compression ratio may display the large-scale motion of particles and may deduce noisy. In this study, the relative error of the wavelet packet image compression technique was lower than that of the standard wavelet image compression technique. The higher compression ratio of 64:1 can be realized without losing significant flow information in PIV processing. It could say that the wavelet packet could provide a better compression performance than the standard wavelet image compression technique when compressing PIV images.
  • M. Takei, H. Li, M. Ochi, Y. Saito, K. Horii
    Handbook of Powder Technology 10 783-789 2001年  査読有り
  • 木村 元昭, 武居 昌宏, HO Chih-Ming, 李 輝, 斎藤 兆古, 堀井 清之
    可視化情報学会論文集 21(4) 71-78 2001年  
    本研究はMEMSマイクロせん断応力イメージチップにより，乱流境界層内のせん断応力を准2次元的に測定し，そのデータに離散値系ウェーブレット変換を施し壁面せん断応力縞構造のより詳細な抽出を行うことを目的としている．MEMSマイクロせん断応力イメージチップにより壁面せん断応力縞構造の時間空間准2次元分布が測定された．同データに離散値系ウェーブレット変換が施され，周波数帯域別にせん断応力縞状構造を分離し，各周波数レベルおきに壁面せん断応力の構造を可視化することができた．また，壁面せん断応力のエネルギー保有領域に相当するレベル0は主流の影響を強く受けること，また，慣性小領域に相当するレベル1と2により壁面せん断応力の縞状構造がより鮮明に可視化することができた．更に，レベル4と5の散逸領域である高周波数領域では粘性の影響が強く現れ，レイノルズ数が低くなるほど渦構造が散逸していく過程が可視化された．
  • 武居 昌宏, M.Kimura, M.Takei, K. Vierow, Y.Saito, K.Horii, A.Saima
    米国流体可視化学会学会誌 8 149-164 2001年  
  • 武居 昌宏, M. Takei, H.Li, M. Ochi, Y. Saito, K. Horii
    パウダーテクノロジー誌 エルセビア 112(3) 289-298 2000年10月  
  • H Li, M Takei, M Ochi, Y Saito, K Horii
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 42(138) 190-195 2000年2月  
    To evaluate unsteady eddy structures of a plane turbulent jet in the dimension of time and scale, velocity signals were analyzed using continuous and discrete wavelet transforms in this paper. By analyzing the distribution of coefficients of continuous wavelet transform, localized nearly periodic eddy motions with a=64, 100 and 180 ms were observed in the shear layer of x/d=8.5 in the time ranges of t=0-220, 280-600 and 680-1000 ms, respectively. From multiresolution analysis or discrete wavelet transform, the peak that appears in the component of fluctuating velocity represented the passing of eddy through the shear layer and concentration of the energy of the flow at one instant. The intermittent eddy phenomenon or zero components of fluctuating velocity can be observed at higher levels or smaller scales.

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  • Yosephus Ardean Kurnianto Prayitno, Yoshiyuki Iso, Tong Zhao, Masahiro Takei
    International Conference on Nuclear Engineering, Proceedings, ICONE 2019年5月18日
    Copyright © 2018-2019 by JSME The demand for high separation efficiency needs an advanced device which can be installed in the separation machinery. To meet this demand, the development of a wireless electrical resistance detector (WERD) was introduced. This research presents particle sedimentation thickness detection method in centrifugal separation system using WERD. The main focus is to observe the particle sedimentation thickness in the specific positions inside an industrial-scale centrifuge. The wireless apparatus has an excellent performance in ultra-high rotation operating speed due to its light weight and flexibility. In this study, the solid phase was represented by acrylic particles of diameter D = 10μm. The acrylic particles were mixed with NaCl solutions and pumped into the centrifuge. As a result, the particle sedimentation thickness nearer to the liquid discharge port is low. Under Re1 = 383.71, the thickness at Z1 = 0.8D and at Z3 = 1.4 are lP1 = 1.15 mm and lP3 = 1.84 mm, respectively. A higher feeding flow rate gives a thicker particle sedimentation thickness. Under Re2 = 1151.15 at Z3 = 1.4D, the particle sedimentation thickness increases by 43%. These results are relative to the constant relative centrifugal force, RCF = 2130G therefore we conclude that the separation efficiency can be optimized by controlling the feeding rate and the rotational velocity of the centrifuge. These findings confirm that WERD is able to monitor the separation process in a centrifuge.
  • Wuqiang Yang, Zhen Ren, Masahiro Takei, Jiafeng Yao
    IST 2018 - IEEE International Conference on Imaging Systems and Techniques, Proceedings 2018年12月14日
    © 2018 IEEE. While electrical capacitance tomography (ECT) and electrical impedance tomography (EIT) have found many successful industrial applications, only recently, research into medical applications of ECT and EIT were carried out at University of Manchester and Chiba University, including (1) Visualization of tooth surface by ECT for tooth canal treatment, (2) Visualization by ECT and EIT for revision hip replacement surgery, (3) Microfluidics for cell sensing and manipulation, (4) Imaging clots in blood flows and (5) Non-intrusive diagnosis of lymph problems. This paper will review the above medical applications of electrical tomography, from necessity of the work or problems to be addressed, sensing principles, experiment arrangement to some initial results. In addition, other research related to medical application of electrical tomography will also be briefly reviewed, such as by Swisstom AG in Switzerland, Dartmouth College in USA and some universities in China.
  • Daisuke Kawashima, Xiayi Liu, Michiko Sugawara, Hiromichi Ohara, Masahiro Takei
    MHS 2017 - 28th 2017 International Symposium on Micro-NanoMechatronics and Human Science 2018年2月28日
    © 2017 IEEE. Electrical impedance spectroscopy (EIS) has been proven to be a useful technique for analyzing biological cell suspensions and tissues because of its capacity of noninvasive measurement. In this paper, the electrical characteristics of medical research council cell strain 5 (MRC-5) are detected by EIS in a multi-layered microchannel. In this research, the equivalent circuit of MRC-5 solution is created by the principle of cell electrical properties. In the experiments, MRC-5 and yeast cells are detected by EIS in multi-layered microchannel, the results reveal that EIS in the micro sensor distinguishes the different cells by their different electrical impedance.
  • The Ninth Thermal and Fluids Engineering Conference(TFEC9) 2017年10月
  • Min-Ho Jeon, Kyung-Youn Kim, Masahiro Takei
    2016 IEEE INTERNATIONAL INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE PROCEEDINGS 2016年 IEEE
    It is important to get reliable measurement data in Electrical impedance tomography (EIT) for getting satisfactory reconstruction result. Because EIT inverse problem is non-linear and ill-posed, incorrect data such as measured data through fault electrode can effect the estimation of resistivity distribution. So, EIT measurement system with methods for checking reliability has been developed. However, most existing methods require extra cost to evaluate reliability of EIT system. This paper presents modified Gauss-Newton (GN) method based on random sample consensus (RANSAC) algorithm for finding fault electrodes and getting good reconstructed image with faulty data for two-phase flow application. Also, suitable residual equation is proposed for determining the threshold to use RANSAC algorithm. Numerical simulations are performed to validate the performance of the proposed method. The results show that the proposed method has a good reconstruction performance compared to the conventional GN method.
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