@article{Limsimarat2007,

title = {Dynamic simulation using a multipolar model of particles under dielectrophoretic force},

author = {A Limsimarat and B Techaumnat},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34447540151&doi=10.1016%2fj.elstat.2007.05.003&partnerID=40&md5=ef376657450abc4ee0d67225dbec37f6},

doi = {10.1016/j.elstat.2007.05.003},

issn = {03043886},

year  = {2007},

date = {2007-01-01},

journal = {Journal of Electrostatics},

volume = {65},

number = {10-11},

pages = {672-679},

abstract = {This article presents the simulation of an electrorheological (ER) fluid system by using a multipole model that includes multipolar interactions between particles. The model uses the multipole re-expansion and the method of images for calculating electric field and force. The highest order of multipoles (Nmp) and the number of iterations (Niter) used in the method of images can be chosen for the accuracy of the force approximation and the simulation time required. Study of a two-particle configuration shows that the force does not increase linearly with increasing Nmp and Niter. The specific case Nmp=4 and Niter=2 is chosen for dynamic simulation. We have performed the simulation of a system of 20 particles, and compared the formulation of particle chains with that obtained using the dipole model. The results imply that the response time for the change in viscosity of real-ER fluids is significantly shorter than that predicted by the dipole model. © 2007 Elsevier B.V. All rights reserved.},

note = {cited By 13},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2007a,

title = {Analysis of the effects of an orifice plate on the membrane potential in electroporation and electrofusion of cells},

author = {B Techaumnat and M Washizu},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947654357&doi=10.1088%2f0022-3727%2f40%2f6%2f036&partnerID=40&md5=3fb6cd2f44ca6a5d01bc87c5ae630344},

doi = {10.1088/0022-3727/40/6/036},

issn = {00223727},

year  = {2007},

date = {2007-01-01},

journal = {Journal of Physics D: Applied Physics},

volume = {40},

number = {6},

pages = {1831-1837},

abstract = {This paper presents a numerical analysis of the membrane voltage induced on biological cells, under the influence of an externally applied field in such processes as electroporation or electrofusion. We focus on the configurations in which an insulator plate with an orifice is used and study the cases of (a) a cell placed on the orifice or (b) two cells in contact at the orifice, when a stepwise voltage is applied across the plate. Formulation based on the boundary element method is made assuming that a biological membrane is an infinitesimally thin insulator. Results of the calculation show that, due to the field constriction created by the orifice plate, almost all the externally applied voltage is imposed on the membrane at the orifice, and the membrane voltage outside the orifice is virtually zero; field tailoring with the use of the orifice plate enables control over the magnitude and localization of the membrane voltage. It is also shown that we can induce breakdown exclusively around the contact point of a pair of cells for high-yield electrofusion with such a geometry. © 2007 IOP Publishing Ltd.},

note = {cited By 27},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Limsimarat2007a,

title = {Dynamic simulation including multipolar interactions of a system of dielectric particles under electric field},

author = {A Limsimarat and B Techaumnat},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548715794&doi=10.1541%2fieejfms.127.500&partnerID=40&md5=ea71c813460c56eabcf3ad9693d1c165},

doi = {10.1541/ieejfms.127.500},

issn = {03854205},

year  = {2007},

date = {2007-01-01},

journal = {IEEJ Transactions on Fundamentals and Materials},

volume = {127},

number = {9},

pages = {500-504},

publisher = {Institute of Electrical Engineers of Japan},

abstract = {This article presents the dynamic simulation of dielectric particles under an electric field. A multipole model including multipolar interactions between particles is used here to calculate an electric field on the particles and then the force from the electric field. The simulation has been performed on the systems of an ER fluid having different volume fractions. The simulation results by the multipole model have been compared to those by the dipole model, which is oñen used in the existing works. The comparison shows that, for the system of very low volume fraction, the particles bridge the electrodes faster by the multipole model than by the dipole model. For the systems of higher volume fraction, the aggregation of the particles depends greatly on their initial positions. The results also show that, in a real ER fluid, the ordering of the particle chains may not be parallel well to the field direction as that predicted by the dipole model.},

note = {cited By 0},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Washizu2007,

title = {Cell membrane voltage during electrical cell fusion calculated by re-expansion method},

author = {M Washizu and B Techaumnat},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947674576&doi=10.1016%2fj.elstat.2006.12.001&partnerID=40&md5=cd3ff9471b201c6d9e77cbcec72e239d},

doi = {10.1016/j.elstat.2006.12.001},

issn = {03043886},

year  = {2007},

date = {2007-01-01},

journal = {Journal of Electrostatics},

volume = {65},

number = {9},

pages = {555-561},

publisher = {Elsevier},

abstract = {In electrical cell fusion, two cells are first brought into contact by dielectrophoresis, and then a pulsed voltage is applied to induce reversible membrane breakdown at the contact point, by which the membranes of the two cells are reconnected to form a fusant cell. The prediction of the membrane voltage is a crucial issue for high fusion yield, however, its mathematical expression is known only for the case of an isolated cell in a uniform external field. In this paper, we employ the re-expansion method for the transient field analysis of such a multiple cell system. Each cell is modeled by an infinitesimally thin spherical insulating membrane in conducting media, on which accumulation of free charge occurs when an external field is applied. It is shown that the system has two time constants: (a) that governed by the conductivity and the permittivity of the media and (b) that of charging the membrane capacitance through the conducting media, and that the former is far shorter than the latter. Hence, the time variation due to the former is neglected to obtain a simplified expression for the membrane voltage. By expanding the potential into Legendre harmonic components and relating the coefficients for each cell based on the re-expansion method, a differential equation governing the membrane voltage buildup is obtained. The numerical calculation is performed for the axisymmetric case of two cells in contact, to which a step-wise voltage is applied. It is found that the maximum membrane voltage occurs initially at the contact point, but when the steady state is reached, it moves to the ends of the cell pair, and might lead to unsuccessful fusion. The analysis suggests that high-yield fusion may be achieved by an application of shorter pulse, or of a non-uniform field to concentrate the voltage drop at the contact point. © 2007 Elsevier B.V. All rights reserved.},

note = {cited By 17},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2006,

title = {Calculation of the electric field in arrangements of intersecting spheres},

author = {B Techaumnat and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845728571&doi=10.1063%2f1.2369631&partnerID=40&md5=26f620270fc04f9456b496ef25fdcb1c},

doi = {10.1063/1.2369631},

issn = {00218979},

year  = {2006},

date = {2006-01-01},

journal = {Journal of Applied Physics},

volume = {100},

number = {11},

abstract = {The application of the method of images to the calculation of electric field in arrangements of intersecting conducting spheres is presented. The multipole re-expansions are utilized to determine the multipole images and the potential coefficients. The method is applicable for cases of electrically floating, grounded, or energized conducting spheres that intersect each other. Examples are given for two grounded intersecting spheres of equal radii and those of different radii, respectively, under an external uniform field. The results for the spheres of equal radii agree well with the analytical solutions for the case of completely overlapped spheres and touching spheres, respectively. For the spheres of different radii, the numerical results show that the method may also be used when the degree of intersection is not too high. © 2006 American Institute of Physics.},

note = {cited By 2},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2006a,

title = {Calculation of electric field in two-dimensional arrangements by the method of multipole images},

author = {B Techaumnat and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745943452&doi=10.1016%2fj.elstat.2006.01.004&partnerID=40&md5=5488528a5915ac46788babe05d3c2e06},

doi = {10.1016/j.elstat.2006.01.004},

issn = {03043886},

year  = {2006},

date = {2006-01-01},

journal = {Journal of Electrostatics},

volume = {64},

number = {10},

pages = {706-716},

abstract = {This paper presents the method of images for calculating electric field in two-dimensional arrangements. The method utilizes multipoles as the images to satisfy boundary conditions. The images are given for planar or cylindrical boundaries between two dielectrics and for those between a dielectric and a conductor. We introduce the use of three kinds of multipole re-expansions, which enables the calculation of images in complicated arrangements. The method has a clear advantage over using only line charges or line dipoles when the arrangement under consideration consists of more than two objects. Calculation examples are given to demonstrate the application of the method. The calculation results show that in an arrangement where the field is highly non-uniform, high accuracy can be attained by using the method. © 2006 Elsevier B.V. All rights reserved.},

note = {cited By 6},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2006b,

title = {Analysis of the electric field and force in an arrangement of a conducting sphere and a plane electrode with a dielectric barrier},

author = {B Techaumnat and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646410711&doi=10.1109%2fTDEI.2006.1624278&partnerID=40&md5=08df00b90048d970c9b8ab5fa19b174f},

doi = {10.1109/TDEI.2006.1624278},

issn = {10709878},

year  = {2006},

date = {2006-01-01},

journal = {IEEE Transactions on Dielectrics and Electrical Insulation},

volume = {13},

number = {2},

pages = {336-344},

abstract = {This paper presents an analysis of the electric field and dielectrophoretic force in an arrangement consisting of an uncharged conducting sphere and a plane electrode with a dielectric barrier. The electric field is calculated by using the method of multipole images using an iterative algorithm proposed for calculating the images of the dielectric barrier of finite thickness. The calculation results show electric field intensification due to the presence of the dielectric barrier having higher permittivity, ε S, than that of the surrounding medium, ε E; however, if the barrier is separated from the conducting sphere by at least the sphere radius, its influence is negligible. Inside the dielectric barrier, the electric field on the axis of symmetry becomes more uniform and the average field significantly increases with decreasing its thickness. For a case where dielectric barrier is sufficiently thin, the electric field at the contact point and the force on the conducting sphere vary approximately as power functions of ε S / ε E. © 2006 IEEE.},

note = {cited By 17},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2006c,

title = {Electric field and force on a conducting sphere in contact with a dielectric solid},

author = {B Techaumnat and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-31344477601&doi=10.1016%2fj.elstat.2005.05.003&partnerID=40&md5=ee1e6057b84731d0d8a6e829c7a7ec3a},

doi = {10.1016/j.elstat.2005.05.003},

issn = {03043886},

year  = {2006},

date = {2006-01-01},

journal = {Journal of Electrostatics},

volume = {64},

number = {3-4},

pages = {165-175},

abstract = {This paper presents the analysis of electric field and force on a conducting sphere lying on a dielectric solid under a uniform field. To achieve high accuracy, we have applied the analytical method of successively placing three infinite sequences of point and dipole charges (zero- or first-order multipoles). The electric field is highest at the contact point, called the triple junction, where the conductor, the dielectric solid, and the surrounding medium (gas or vacuum) meet together. Both the contact-point field and the force increase with the permittivity ratio of the solid to that of the surrounding medium. The resulting force always attracts the sphere to the solid, in contrast to the repulsive force in the case of a conducting sphere lying on a plane conductor under an external field. We have given very simple formulae for approximating the contact-point field and the force which agree with the precise values within a difference of 3% for permittivity ratios up to 32 and 64, respectively. © 2005 Elsevier B.V. All rights reserved.},

note = {cited By 12},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Limsimarat2005,

title = {Electric field and force on a dielectric particle between two diverging plate electrodes},

author = {A Limsimarat and B Techaumnat},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18244373948&doi=10.1016%2fj.elstat.2005.03.046&partnerID=40&md5=5837880966c5b088e2ecf46af85f84d1},

doi = {10.1016/j.elstat.2005.03.046},

issn = {03043886},

year  = {2005},

date = {2005-01-01},

journal = {Journal of Electrostatics},

volume = {63},

number = {6-10},

pages = {789-794},

abstract = {This paper presents an analysis of the electric field and force on a dielectric particle in a non-uniform field varying in three dimensions. The electric field is calculated by the method of multipole images using fundamental solutions of the Laplace's equation and the multipole re-expansion including multipole rotation. From the electric field, the dielectrophoretic (DEP) force acting on the particle is calculated. The results show that the force attracting the particle to the higher field region depends strongly on the position of the particle. Approximation by an effective dipole gives significantly smaller forces than our results. © 2005 Elsevier B.V. All rights reserved.},

note = {cited By 4},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat20043337,

title = {Electric field and dielectrophoretic force on a dielectric particle chain in a parallel-plate electrode system},

author = {B Techaumnat and B Eua-Arporn and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-10644276441&doi=10.1088%2f0022-3727%2f37%2f23%2f017&partnerID=40&md5=ae496c25e7f6865e9541d85a566e890c},

doi = {10.1088/0022-3727/37/23/017},

issn = {00223727},

year  = {2004},

date = {2004-01-01},

journal = {Journal of Physics D: Applied Physics},

volume = {37},

number = {23},

pages = {3337-3346},

abstract = {This paper presents results of calculations of the electric field and dielectrophoretic force on a dielectric particle chain suspended in a host liquid lying between parallel-plate electrodes. The method of calculation is based on the method of multipole images using the multipole re-expansion technique. We have investigated the effect of the particle permittivity, the tilt angle (between the chain and the applied field) and the chain arrangement on the electric field and force. The results show that the electric field intensification rises in accordance with the increase in the ratio of the particle-to-liquid permittivity, ⌈ε. The electric field at the contact point between the particles decreases with increasing tilt angle, while the maximal field at the contact point between the particles and the plate electrodes is almost unchanged. The maximal field can be approximated by a simple formula, which is a quadratic function of ⌈ε. The dielectrophoretic force depends significantly on the distance from other particles or an electrode. However, for the tilt angles in this paper, the horizontal force on the upper particle of the chain always has the direction opposite to the shear direction. The maximal horizontal force of a chain varies proportional to (⌈ε - 1)1.7 if the particles in the chain are still in contact with each other. The approximated force, based on the force on an isolated chain, has been compared with our calculation results. The comparison shows that no approximation model agrees well with our results throughout the range of permittivity ratios.},

note = {cited By 14},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat20041586,

title = {Calculation of electric field and dielectrophoretic force on spherical particles in chain},

author = {B Techaumnat and B Eua-Arporn and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1142304473&doi=10.1063%2f1.1637138&partnerID=40&md5=4864fe44b5d1e594e0ae645dff89f38c},

doi = {10.1063/1.1637138},

issn = {00218979},

year  = {2004},

date = {2004-01-01},

journal = {Journal of Applied Physics},

volume = {95},

number = {3},

pages = {1586-1593},

abstract = {An analytical method for calculating electric field in 3D arrangements of spherical particles is presented and applied to the calculation of the dielectrophoretic force on particles in a dielectric fluid. The method is based on the multipole re-expansion and the method of images, which utilizes fundamental solutions for several arrangements of a multipole. It is capable of calculating electric field for various conditions of particles. Thus, the calculation results show that the force on a particle chain depends greatly on the angle between the applied field and the chain.},

note = {cited By 30},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2004,

title = {Electric field and dielectrophoretic force on particles with a surface film},

author = {B Techaumnat and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-9944235891&doi=10.1063%2f1.1801161&partnerID=40&md5=8fc813f56cc33244c4d1bf39278ab4d8},

doi = {10.1063/1.1801161},

issn = {00218979},

year  = {2004},

date = {2004-01-01},

journal = {Journal of Applied Physics},

volume = {96},

number = {10},

pages = {5877-5885},

abstract = {This article presents the analysis of the electric field and dielectrophoretic force on spherical particles with a surface film. In the analysis, we use the method of images with the fundamental solutions given for the various types of particles composed of a core and a surface film. The concept of the apparent conductivity is introduced to clarify the difference between the particle types. The analysis shows that the response of a particle with a surface film to an external field is unique and generally cannot be obtained by replacing the particle with a homogeneous particle. Using numerical examples, we compare the field and force characteristics between the particles that are of different types but exhibit an identical response to a uniform external field. The electric field and force are found smaller on the conductor-core particle but greater on the dielectric-core particle compared with the particle without any surface film. We have calculated the electric field and force by using the boundary element method in which a surface film is treated as a zero-thickness medium. The propriety of such treatment of a surface film depends not only on the film properties but also on the external field. © 2004 American Institute of Physics.},

note = {cited By 7},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2004a,

title = {Optimization of a post-type spacer in a gas insulated system under three-dimensional conditions},

author = {B Techaumnat and S Hamada and T Kawamoto and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-6344223565&doi=10.1109%2fTDEI.2004.1324345&partnerID=40&md5=2929b9c9911764f0e047d69eb3bc4dae},

doi = {10.1109/TDEI.2004.1324345},

issn = {10709878},

year  = {2004},

date = {2004-01-01},

journal = {IEEE Transactions on Dielectrics and Electrical Insulation},

volume = {11},

number = {4},

pages = {561-567},

abstract = {This paper describes the optimization of a post-type spacer in a gas insulated system. The electric field calculation and the optimization have been performed in three-dimensional conditions. We have utilized the boundary element method to calculate the electric field distributions and the Marquardt method to improve the profile of the spacer so as to minimize the maximal electric field on the spacer surface. The optimization has been performed for spacers with cylindrical column, circular, and elliptical cross-sections, respectively. We have varied additional parameters, such as the permittivity of a spacer and the radius ratio of an inner conductor and a sheath. For elliptical cross-section spacers, the optimization has reduced the maximal value of the total field strength up to 35 %, and the maximal value of the tangential field strength up to 56 % compared with the respective maximal field without a spacer.},

note = {cited By 7},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2003a,

title = {Calculation of the electric field for lined-up spherical dielectric particles},

author = {B Techaumnat and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141953883&doi=10.1109%2fTDEI.2003.1219647&partnerID=40&md5=e02590ef9b68d61dc2d1eba611086ceb},

doi = {10.1109/TDEI.2003.1219647},

issn = {10709878},

year  = {2003},

date = {2003-01-01},

journal = {IEEE Transactions on Dielectrics and Electrical Insulation},

volume = {10},

number = {4},

pages = {623-633},

abstract = {This paper calculates the electric field in arrangements of dielectric particles. An analytical method is presented in the paper. The method repetitively inserts monopoles and multipoles until all the boundary conditions are satisfied, so that unlike the existing methods, it does not require setting up a linear equation system in the calculation. It can be applied to various types of energization such as a uniform field, spherical electrodes, or planar electrodes. The method and the BEM, a numerical method, have been utilized to investigate the effects of the particle number and particle permittivity. The authors have compared the results by the analytical method with those by the numerical method, and found that the accuracy of the numerical method greatly varies from less than 10-4% to more than 2%, depending on the condition of the calculation arrangements.},

note = {cited By 23},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2002,

title = {Effect of conductivity in triple-junction problems},

author = {B Techaumnat and S Hamada and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036722462&doi=10.1016%2fS0304-3886%2801%2900219-4&partnerID=40&md5=91a3c4f1b34ae7fd2759a0902a4071b2},

doi = {10.1016/S0304-3886(01)00219-4},

issn = {03043886},

year  = {2002},

date = {2002-01-01},

journal = {Journal of Electrostatics},

volume = {56},

number = {1},

pages = {67-76},

abstract = {The paper describes the electric field behavior in triple-junction problems for an arrangement with a contact angle between 0 and π/2. We have fully analyzed the effects of volume and surface conductivity by the results of both applying an analytical solution and numerically calculating electric field distributions. The numerical field calculation is performed by the boundary element method. The analytical solution proposed here agrees well with the numerical calculation results. The presence of volume conductivity usually enhances the field singularity at a contact point, while surface conductivity moderates the field to a uniform distribution near a contact point. © 2002 Elsevier Science B.V. All rights reserved.},

note = {cited By 13},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Techaumnat2002a,

title = {Electric field behavior near a zero-angle contact point in the presence of surface conductivity},

author = {B Techaumnat and S Hamada and T Takuma},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036693408&doi=10.1109%2fTDEI.2002.1024430&partnerID=40&md5=e614f67144780069abf577f959eeda23},

doi = {10.1109/TDEI.2002.1024430},

issn = {10709878},

year  = {2002},

date = {2002-01-01},

journal = {IEEE Transactions on Dielectrics and Electrical Insulation},

volume = {9},

number = {4},

pages = {537-543},

abstract = {The paper describes the electric field behavior near a contact point in various arrangements with a zero contact angle when surface conductivity is present on a solid surface. Electric field distributions are calculated for arrangements with three contact conditions: point, line, and surface contact. We focus on the effect of surface conductivity on the electric field. It was found that the presence of surface conductivity results in the electric field intensification. Similarly to the effect of volume conductivity, when the surface conductivity is higher than a certain value, a change in the position of the peak electric field takes place. The effect of the surface conductivity is noticeable for as low as 0.8 nS.},

note = {cited By 3},

keywords = {},

pubstate = {published},

tppubtype = {article}

}