Hydrodynamic Analysis of Electroosmotic Flow in Capillary

Osuga, Toshiaki; Sakamoto, Hideo; Takagi, Toshio

doi:10.1143/jpsj.65.1854

Cited by 10 publications

(7 citation statements)

References 3 publications

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“…Hereafter, it is assumed that Tc = 0 and Ts = 1. The planar thermal conduction equation is derived from Equation (2.6) with for n = 1 as By applying the boundary conditions in Equation (2.7) to Equation (2.8), the growth of the temperature profile is analytically derived as [1,18,19].…”

Section: Convex Upward Temperature Profile Formed By the Advection Termmentioning

confidence: 99%

“…An infinite straight cylinder submerged in a fluid is assumed to suddenly start to move in the axial direction with a constant velocity V at t = 0, where t is the time. When no vortexes are generated, the translational laminar flow layers (flows in the axial direction with cylindrical symmetry) are represented by a telescope 2 model [1], grow from the inner surface of the cylinder towards its central axis, and finally approach a flat flow profile [2]. The growth period tg is defined as the time when the difference between the fluid velocity along the cylinder axis and V becomes less than (1/100) V and expressed as tg = 5R 2 ρ/2.4 2 μ, where R, ρ, and μ are the inner radius of the cylinder and the density and viscosity of the fluid, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…The measurement of the viscosity should start after the torque reaches a steady state. Therefore, the evaluation of tg and ta, which are the transient times moving towards the steady state, is often required in scientific measurements [1].…”

Section: Introductionmentioning

confidence: 99%

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Thermal Conduction in Higher-Dimensional Sphere and Application to Fluid Rotation

Osuga¹

2017

NNOA

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When two parallel disks, a cylinder, and a sphere having a static fluid within start to rotate, the increase in the angular velocity of the laminar fluid layers starting coaxial rotation was found to be mathematically equivalent to the thermal conduction of one-, four-, and five-dimensional spheres heated from their surfaces, respectively. The thermal conduction of an n-dimensional sphere for 4 ≤ n ≤ 100 was numerically simulated using a time step t and radial division r. The growth period required to achieve a final flat temperature profile was defined as the time when the center temperature reached 99/100 of the surface temperature. The growth period was numerically determined to be proportional to n -1.25 , which was analytically supported by the thermal conduction of n-dimensional cubes inscribed within and circumscribing an n-dimensional sphere. Because the exponential time change in the surface temperature gradient was almost similar for the spherical heating of 1-8-dimensional spheres, the entire thermal transport in the n-dimensional sphere for 1 ≤ n ≤ 8 was numerically determined to be similar with respect to the growth period, which was supported by the analytical solutions for spheres with 1 ≤ n ≤ 3 by regarding slab and cylindrical thermal conduction as the heating modes of one-and two-dimensional spheres, respectively. The observed attenuation periods of fluid rotation in cylinder and spherical flasks were supported by the numerically determined growth periods of the thermal conduction of four-and five-dimensional spheres, where the rotation in the cylinder should be treated as disk rotation when the height is less than the radius. Heat Transfer between Adjacent n-DimensionalSpherical Shells: The inward thermal conduction of a sphere heated from the surface shown in Figure 1a is considered. The entire volume n V and surface area n S of the n-dimensional sphere with a radius of a and the relation between n V and n S are given by [17].

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Section: Convex Upward Temperature Profile Formed By the Advection Termmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal Conduction in Higher-Dimensional Sphere and Application to Fluid Rotation

Osuga¹

2017

NNOA

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“…A numerical analysis of the cross-channel and entry flow profiles have been presented by Patankar et al [13] and Yang et al [14], respectively. Some studies have been focused on a theoretical description of EOF [15][16][17][18][19]. One of the earliest works dealing with this task is that of Rice and Whitehead [15] who derived the steady-state velocity profile of a liquid solution in a narrow cylindrical capillary.…”

Section: Introductionmentioning

confidence: 99%

“…The effects of the geometry and the flow field conditions on the separation resolution in microchannels of an electrophoresis chip are analyzed by Fu et al [17]. The development of EOF velocity profile was solved by Osuga and Sakamoto [18,19]. They assumed, that the charged double-layer exists in a limited region near the capillary wall.…”

Section: Introductionmentioning

confidence: 99%

Electroosmotic flow in capillary channels filled with nonconstant viscosity electrolytes: Exact solution of the Navier-Stokes equation

Otevrel

Klepárnı́k

2002

Electrophoresis

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The partial differential equation describing unsteady velocity profile of electroosmotic flow (EOF) in a cylindrical capillary filled with a nonconstant viscosity electrolyte was derived. Analytical solution, based on the general Navier-Stokes equation, was found for constant viscosity electrolytes using the separation of variables (Fourier method). For the case of a nonconstant viscosity electrolyte, the steady-state velocity profile was calculated assuming that the viscosity decreases exponentially in the direction from the wall to the capillary center. Since the respective equations with nonconstant viscosity term are not solvable in general, the method of continuous binding conditions was used to solve this problem. In this method, an arbitrary viscosity profile can be modeled. The theoretical conclusions show that the relaxation times at which an EOF approaches the steady state are too short to have an impact on a separation process in any real systems. A viscous layer at the wall affects EOF significantly, if it is thicker than the Debye length of the electric double layer. The presented description of the EOF dynamics is applicable to any microfluidic systems.

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Capillary Electrophoresis

1998

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This review represents the fifth in the series of fundamental reviews on capillary electrophoresis (CE) appearing in the journal. This review, which covers the period from October 1995 to October 1997, focuses on significant developments in the theory and practice of CE. Following the previously successful format, included here are papers covering capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), capillary gel electrophoresis (CGE), capillary isoelectric focusing (CIEF), capillary isotachophoresis (CITP), and capillary electrochromatography (CEC). Within these separation systems we emphasize advances in the underlying principles and theory including performance optimization, instrumental configurations (sample introduction, CEC, microchips, etc.), and detection strategies. Publications that appeared during the covered period in which the emphasis was on specific applications of CE have not been included in this review. These can be easily accessed through various numbers of existing application reviews (1) or applicationsspecific literature searches.The review is not intended to provide a comprehensive compilation of the more than 3600 CE papers published between October 1995 and October 1997. The author's intent, rather, was to gather and present those papers representing fundamental developments across the CE landscape. It is hoped that the result will provide a flavor for the current directions in which CE is evolving, where CE has matured, and perhaps offer insight to some of the latent, untapped, promise of CE.

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Hydrodynamic Analysis of Electroosmotic Flow in Capillary

Cited by 10 publications

References 3 publications

Thermal Conduction in Higher-Dimensional Sphere and Application to Fluid Rotation

Thermal Conduction in Higher-Dimensional Sphere and Application to Fluid Rotation

Electroosmotic flow in capillary channels filled with nonconstant viscosity electrolytes: Exact solution of the Navier-Stokes equation

Capillary Electrophoresis

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