Three dimensional (3D) stepped electrodes dramatically improve the flow rate and frequency range of ac electro-osmotic pumps, compared to planar electrodes. However, the fabrication of 3D stepped electrodes for ac electro-osmosis (ACEO) pumps usually involves several processing steps. This ...

Three-dimensional (3D) ac electro-osmotic (ACEO) pumps have recently been developed that are much faster and more robust than previous planar designs. The basic idea is to create a �fluid conveyor belt� by placing opposing ACEO slip velocities at different heights. Current designs involve electrodes with electroplated steps, whose ...

unsuitable for biological applica- tions. Due to such drawbacks, the use of electrokinetic EK micropumps- clude dc and ac micropumps. In a dc pump electro-osmotic EO flow is induced by an external tangential of directed flow over the activated micropump. For more information on EPAPS, see http://www. aip

This paper details the development of an integrated AC electro-osmotic (ACEO) microfluidic pump for dilute electrolytes consisting of a long serpentine microchannel lined with three dimensional (3D) stepped electrode arrays. Using low AC voltage (1 V rms, 1 kHz), power (5 mW) and current (4.5 mA) in water, the ...

Pumps with step microelectrodes subjected to an ac voltage are known to have faster pumping rates than those with planar asymmetric microelectrodes. The driving force for pumping in these systems is ac electro-osmosis. This paper aims to understand the flow behaviors of ...

Pumps with step microelectrodes subjected to an ac voltage are known to have faster pumping rates than those with planar asymmetric microelectrodes. The driving force for pumping in these systems is ac electro-osmosis. This paper aims to understand the flow behaviors of ...

- teracting portions are then recessed relative to the bulk fluid. These are "rollers" in the fluid conveyor improve performance by minimizing this new source of competition. In principle, we could eliminate might etch the recesses into the sub- strate rather than building the steps up from it. Regardless

Lab-on-a-chip devices require integrated pumping and fluid control in microchannels. A recently developed mechanism that can produce fluid flow is an integrated ac-electro-osmosis micropump. However, like most electrokinetic pumps, ac-electro-osmotic pumps are incapable of handling backpressure ...

ac electro-osmosis (ACEO) has emerged recently as a promising strategy for fluid transport at microscale. With an array of planar interdigital electrodes immersed in an electrolyte, different charging mechanisms at electrode/electrolyte interface and electrokinetic surface flows can be induced by nonuniform electrical fields. To implement ACEO micropump, asymmetry in an ...

Sep 19, 2005 ... The proposed program will evaluate the use of electro-osmosis to supply and control the flow of ionic liquid propellants to micronewton ...

A microfluidic pump and mixer design based on ac faradaic polarization is proposed. Unlike ac electrokinetic devices based on capacitive charging of the electrodes, the design yields a net electro-osmotic flow for high-conductivity electrolytes at high voltages and frequencies without producing gas bubbles or ...

In this paper, a series of numerical simulations was performed to investigate the pumping performance of electro-osmotic micropumps containing electrode arrays patterned on the upper and lower sides of a microchannel. The simulations have been analyzed with a linear electro-osmotic model based upon the Debye-H�ckel theory of the double layer. The ...

In this paper, a series of numerical simulations was performed to investigate the pumping performance of electro-osmotic micropumps containing electrode arrays patterned on the upper and lower sides of a microchannel. The simulations have been analyzed with a linear electro-osmotic model based upon the Debye-H�ckel theory of the double layer. The ...

An AC electrokinetic funnel flow is generated by a planar micro-coil resister design capable of sustaining 3500V without Faradaic reactions. The final line of the serpentine coil exhibits a transverse electro-osmotic slip velocity exceeding 1 cm/sec. Due to side boundaries, a large back pressure is established in the slip direction to produce an intense ...

Research performed at NLR (partly under contract with the Netherlands Agency for Aerospace Programs NIVR) led to a promising variable conductance heat pipe concept based on electro-osmosis: the feedback controllable electroosmotic heat pipe (EOHP). Such a...

This paper deals with the mathematical modeling of traveling-wave ac electro-osmotic micropumps with a zig-zag arrangement of microelectrodes. A mathematical model based on the Poisson-Nernst-Planck-Navier-Stokes description is used in this study within the physically relevant ranges of the model parameters. We present an extensive set of parametrical ...

This paper deals with the mathematical modeling of traveling-wave ac electro-osmotic micropumps with a zig-zag arrangement of microelectrodes. A mathematical model based on the Poisson-Nernst-Planck-Navier-Stokes description is used in this study within the physically relevant ranges of the model parameters. We present an extensive set of parametrical ...

In this work, invoking join asymmetric ac polarization using double half-quadrupole electrodes in a symmetric arrangement, we demonstrate a head-on ac electro-osmotic streaming capable of focusing and trapping DNA molecules efficiently. This is manifested by the observation that picomolar DNA molecules can be trapped into a large ...

Flow forcing by ac electro-osmosis (ACEO) is a promising technique for the actuation and manipulation of micro-flows. Utilization to date mainly concerns pumping and mixing. However, emerging micro-fluidic applications demand further functionalities. The present study explores the first ways to systematically realize this in three-dimensional (3D) ...

In this paper we present an interactive numerical method that can predict ac electro-osmotic flows around completely polarized electrodes. In this method the slip velocity on the electrode surface is calculated by numerically solving the Laplace equation for the potential in the bulk coupled with the dynamical equation for the surface charge density on the ...

Microsensors and micromachines that are capable of self-propulsion through fluids could revolutionize many aspects of technology. Few principles to propel such devices and supply them with energy are known. Here, we show that various types of miniature semiconductor diodes floating in water act as self-propelling particles when powered by an external alternating electric field. The ...

A new method is demonstrated to transport particles, cells, and other microorganisms using rectified ac electro-osmotic flows in open microchannels. The rectified flow is obtained by synchronous zeta potential modulation with the driving potential in the microchannel. Experiments were conducted to transport both neutral, charged particles, and ...

A new method is demonstrated to transport particles, cells, and other microorganisms using rectified ac electro-osmotic flows in open microchannels. The rectified flow is obtained by synchronous zeta potential modulation with the driving potential in the microchannel. Experiments were conducted to transport both neutral, charged particles, and ...

Electro-osmotic flow (EOF) pumps are attractive for fluid manipulation in microfluidic channels. Open channel EOF pumps can produce high pressures and flow rates, and are relatively easy to fabricate on-chip or integrate with other microfluidic or electrical components. An EOF pump design that is conducive to ...

,40 studied the kinetics of hydrogen-bonded interpolymer complexation between dansyl-labeled PAA and PEO upon com- plexation due to that dansyl groups are now located in a more hydrophobic environment of hydrogen-bonded interpolymer complexation between dansyl-labeled PAA and PEO.40 To avoid precipitation

We present a new approach to enhance mixing in T-type micromixers by introducing a constriction in the microchannel under periodic electro-osmotic flow. Two sinusoidal ac electric fields with 180� phase difference and similar dc bias are applied at the two inlets. The out of phase ac electric field induces oscillation of fluid ...

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing ...

We describe the general phenomenon of �induced-charge electro-osmosis� (ICEO) the nonlinear electro-osmotic slip that occurs when an applied field acts on the ionic charge it induces around a polarizable surface. Motivated by a simple physical picture, we calculate ICEO flows around conducting cylinders in steady (DC), oscillatory (AC), and suddenly ...

Electro-Osmotic Mixing in Microchannels by Pong Yu (Peter) Huang MFL TR 2002-01 Microfluidics spanwise electro-osmotic oscillation is very effective under low applied voltages. Decreasing electro-osmotic oscillation. This report is the Sc.M. thesis of Pong Yu (Peter) Huang, supervised by Prof

In this article, we investigate theoretically electro-osmotic flow set up by charged strips on an otherwise uncharged surface. Starting with a single-strip problem we demonstrate that for simple polynomial surface charge distributions several basic solutions can be derived in closed forms constituted by the analogous idea-flow solutions, which provide a more lucid way of ...

The kinesin-microtubule system plays an important role in intracellular transport and is a model system for integrating biomotor-driven transport into microengineered devices. AC electrokinetics provides a novel tool for manipulating and organizing microtubules in solution, enabling new experimental geometries for investigating and controlling the interactions of microtubules ...

We study water flow through carbon nanotubes using continuum theory and molecular dynamics simulations. The large slip length in carbon nanotubes greatly enhances the pumping and electrokinetic energy conversion efficiency. In the absence of mobile charges, however, the electro-osmotic flow vanishes. Uncharged nanotubes filled with pure water can therefore not be used as ...

We study water flow through carbon nanotubes using continuum theory and molecular dynamics simulations. The large slip length in carbon nanotubes greatly enhances the pumping and electrokinetic energy conversion efficiency. In the absence of mobile charges, however, the electro-osmotic flow vanishes. Uncharged nanotubes filled with pure water can therefore not be used as ...

This paper concerns the comparison of electroconvective instability in concentration polarization at an ion-selective membrane with previously reported nonequilibrium electro-osmotic instability. Electro-osmotic formulation represents an asymptotic limit case of the electroconvective one. An improved nonequilibrium electro-osmotic slip ...

The classical Poisson-Boltzmann (PB) theory of electrolytes assumes a dilute solution of point charges with mean-field electrostatics. Even for very dilute solutions, however, it predicts absurdly large ion concentrations (exceeding close packing) for surface potentials of only a few tenths of a volt. In this talk, we adopt a simple model for steric effects with only one parameter (the effective ...

We analyze the AC electro-osmotic motion of a 1:1 aqueous solution, taking into account the difference in mobilities and diffusion coefficients between positive and negative ions. This model serves to understand the behavior of common systems as a solution of NaCl in water. We pay special attention to two cases. First, the case of slightly different ...

TECHNICAL OBJECTIVE: The objective of this project is to demonstrate and evaluate the use of an Intelligent Single Well Electro-osmotic Dewatering Systems in controlling of water seepage through porous materials such as reinforced concrete. The broad end ...

... STEEL, PULSES, AMMUNITION, LIGHTNING PROTECTION, MOISTURE, DETERIORATION, ARCHES, MODELS, SCALE MODELS, CORROSION ...

... Descriptors : *WATER, *SEEPAGE, *ELECTROOSMOSIS, PROBES, LABORATORY TESTS, CATHODES, WALLS, MINNESOTA, HYDRAULICS ...

/s)U O ACEO (AC electroosmosis) #12;AC electroosmotic pump Advantages � ~1V (less than 5V) DCEO pump ACEO

In this work, we extend previous analyses of ac electro-osmosis to account for the combined action of two experimentally relevant effects: (i) Faradaic currents from electrochemical reactions at the electrodes and (ii) differences in ion mobilities of the electrolyte. In previous works, the ac electro-osmotic motion has been analyzed ...

In this work, we extend previous analyses of ac electro-osmosis to account for the combined action of two experimentally relevant effects: (i) Faradaic currents from electrochemical reactions at the electrodes and (ii) differences in ion mobilities of the electrolyte. In previous works, the ac electro-osmotic motion has been analyzed ...

Cylindrical vortices generated by AC electro-osmotic (AC-EO) flows on microelectrodes have been seen to attract and concentrate micro-particles. The particles are attracted to the vortex by dielectrophoretic (DEP) forces of the underlying micro-electrodes. However, shear-induced particle migration mechanisms can counter the DEP ...

In this work we report a microfluidic platform capable of trapping and concentrating a trace amount of DNA molecules efficiently. Our strategy invokes nonlinear electro-osmotic flow induced by charge polarization under high-frequency ac fields. With the asymmetric quadrupole electrode design, a unique converging flow structure can be created for generating ...

pump for liquid helium transfer in space. The pump is made up of an a.c. induction ... for head and flow by testing the pump in liquid helium. Calculations ...

Electro-osmotic effect in a porous medium arises from the electrically charged double layer at the fluid-solid interface, whereby an externally applied electric field can give rise to fluid flow. The electro-osmotic pump (EOP) is potentially useful for a variety of engineering and biorelated applications, but its generally low efficiency is a negative ...

Electro-osmotic effect in a porous medium arises from the electrically charged double layer at the fluid-solid interface, whereby an externally applied electric field can give rise to fluid flow. The electro-osmotic pump (EOP) is potentially useful for a variety of engineering and biorelated applications, but its generally low efficiency is a negative ...

The addition of minute amounts of chemically inert polyacrylamide polymer to liquids results in large instabilities under steady electro-osmotic pumping through 2 : 1 constrictions, demonstrating that laminar flow conditions can be broken in electro-osmotic flow of viscoelastic material. By excluding shear and imposing symmetry we create a platform where ...

A theoretical study on the transient electro-osmotic flow through a cylindrical microcapillary containing a salt-free medium is presented for both constant surface charge density and constant surface potential. The exact analytical solutions for the electric potential distribution and the transient electro-osmotic flow velocity are derived by solving the ...

A theoretical study on the transient electro-osmotic flow through a cylindrical microcapillary containing a salt-free medium is presented for both constant surface charge density and constant surface potential. The exact analytical solutions for the electric potential distribution and the transient electro-osmotic flow velocity are derived by solving the ...

... Adjustable Speed Drives (ASD), AC induction motors, AC synchronous motors, centrifugal pumps, and positive displacement pumps were ...

... Administrative Instructions, Directive-Type Memorandums and DoD Forms. ... Accession Number : ADA532680. Title : Moisture Control Using ...

... ECM lightning protection system, the potential for hydrogen gas generation by ... A positive electrical pulse causes cations (eg, Ca++) with associated ...

... the effective surface area for water flux after the epoxy coatings had been ... involve relatively thin (up to 12-in.) concrete walls or floor slabs with ...

... Groundwater intrusion through a building's foundation that causes such damage requires ... 10 Current versus time for four different rock specimens ...

... In problem areas, the usual approach to solve groundwater ... is to excavate to expose the wall area and the ... surface and to install a drain tile system ...

We report curious asymmetric induced-charge electro-osmotic (ICEO) flows over a symmetric, planar gate electrode under applied ac electric fields, whereas symmetric, counter-rotating rolls are expected. Furthermore, the asymmetric component of the flow is consistently directed towards the grounded electrode. We propose that capacitive coupling of the gate ...

The present study focuses on the interplay of isotachophoresis (ITP) and electro-osmotic flow (EOF). While EOF is commonly suppressed in ITP applications, we investigate scenarios of the combination of both EOF and ITP. Experimental results of ITP/EOF experiments within cross-patterned polymer chips show characteristic deformations of fluorescent sample zones sandwiched between leading and ...

Recently, there has been a growing interest in using induced electro-osmosis to pump fluids in microfluidic devices. We show that induced electroosmosis can also be used to promote stirring and chaotic advection. To this end, we study theoretically a stirrer in which the flow patterns are alternated in time. We first analyze an idealized embodiment of the stirrer that admits a ...

Three electrochemical chlorinators were developed, tested and evaluated. The first used natural chlorides in the water to produce a chlorine residual; the second and third produced chlorine residuals by electrolysis of brine solution. Brine feed rate of the second chlorinator was controlled by a metering pump; this control in the third chlorinator was by the electro-osmotic ...

Integrated DNA extraction and amplification have been carried out in a microfluidic device using electro-osmotic pumping (EOP) for fluidic control. All the necessary reagents for performing both DNA extraction and polymerase chain reaction (PCR) amplification were pre-loaded into the microfluidic device following encapsulation in agarose gel. Buccal cells ...

Electro-osmotic (EO) pumps directly convert electrical energy into fluids' kinetic energy, which have many advantages such as a simple and compact structure, no mechanical moving parts, and easy integration. In general, it is easy for EO pumps to generate enough pressure but it has been a challenge for EO pumps to ...

Arguments for using limited leakage pumps instead of canned-motor pumps in rcactor coolant primary systems are given. The literature available on the subject is reviewed. (A.C.)

An energy-conversion scheme, which allows efficient exploitation of salinity gradients, is proposed. This is a submarine hydro-electro-osmotic power plant in which fresh surface water is conveyed through a penstock to a submerged hydraulic turbine for the generation of electric power. The water leaves the turbine outlet depressurized and finally diffuses out in the sea, by ...

of the wells drilled for electro-osmotic remediation field installations (3). Typical soil characteristicsElectrolyte Management for Effective Long-Term Electro-Osmotic Transport in Low-Permeability Soils and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 Electro

Electro-osmotic pulse (EOP) was evaluated in the laboratory to compare the electrokinetic forces developed by the EOP system to the hydraulic forces within 4-in.-thick concrete. Systems were installed in two Civil Works structures, the old lock house at L...

Electro-osmotic infusion of ground water or chemically tailored electrolyte is used to enhance, maintain, or recondition electrical conductivity for the joule heating remediation technique. Induced flows can be used to infuse electrolyte with enhanced ionic conductivity into the vicinity of the electrodes, maintain the local saturation of near-electrode regions and resaturate ...

Electro-osmotic infusion of ground water or chemically tailored electrolyte is used to enhance, maintain, or recondition electrical conductivity for the joule heating remediation technique. Induced flows can be used to infuse electrolyte with enhanced ionic conductivity into the vicinity of the electrodes, maintain the local saturation of near-electrode regions and resaturate ...

In the second part of a series on electromagnetic pumping of liquid metals, the design and characteristics of the a-c conduction pump and the induction pump are discussed. Possible future developments in the pumping of liquld metals are described. (J.S.R.)

We report nonintrusive optical microscopy measurements of ensembles of polystyrene colloids in inhomogeneous AC electric fields as a function of field frequency and particle size. By using an inverse Monte Carlo (MC) simulation analysis of time-averaged particle microstructures, we sensitively measure induced dipole-dipole interactions on the kT energy scale. Measurements are ...

We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting ...

We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting ...

A dc current can be pumped through a nanostructure by two out-of-phase ac driving fields. In this approach, we investigate the pumped current properties driven by multiharmonic ac fields in nanowire structures. Considering the first five harmonics, the adiabatically pumping properties driven by ...

Electro-osmotic (or electrokinetic) transport is used to efficiently force a solution (or water) through the interior of the fibers or yarns of textile materials for wet processing of textiles. The textile material is passed between electrodes that apply an electric field across the fabric. Used alone or in parallel with conventional hydraulic washing (forced convection), ...

Electro-osmotic (or electrokinetic) transport is used to efficiently force a solution (or water) through the interior of the fibers or yarns of textile materials for wet processing of textiles. The textile material is passed between electrodes that apply an electric field across the fabric. Used alone or in parallel with conventional hydraulic washing (forced convection), ...

A silica monolith used to support both electro-osmotic pumping (EOP) and the extraction/elution of DNA coupled with gel-supported reagents is described. The benefits of the combined EOP extraction/elution system were illustrated by combining DNA extraction and gene amplification using the polymerase chain reaction (PCR) process. All the reagents necessary ...

Numerical analyses of transient electro-osmosis of a typical non-Newtonian liquid induced by DC and AC electric fields in a rectangular microchannel are conducted in the framework of continuum fluid mechanics. The famous power-law constitutive model is used to express the fluid dynamic viscosity in terms of the velocity gradient. Transient start-up characteristics of ...

... Background Problem Severe mold and rising damp ... Pulsed DC Power Supply Anode - Mortared into Basement Wall And/Or Floor Cations Water ...

Considering electro-osmotic flow in axisymmetric microducts is of both fundamental interest and practical significance. In this paper, an axisymmetric lattice Boltzmann model which solves the complete nonlinear Poisson-Boltzmann equation is presented to obtain the electric potential distribution in the electrolytes, and another axisymmetric lattice Boltzmann model is employed ...

... test section. Anodes in Sections I and 3 were placed 12.192 m from ... depth for each electro-osmotic section and two control sections where there ...

Nonequilibrium electro-osmotic slip causes instability of quiescent ionic conductance through a diffusion layer of a strong electrolyte at a charge selective solid such as ion-exchange membrane or electrode. This instability, as inferred from the outer asymptotic limit of the full singularly perturbed ionic transport problem, is of the short-wave type. This latter is a serious ...

Analytical and numerical studies of secondary electro-osmotic flow (EOF) and its mixing in microchannels with heterogeneous zeta potentials are carried out in the present work. The secondary EOFs are analyzed by solving the Stokes equation with heterogeneous slip velocity boundary conditions. The analytical results obtained are compared with the direct numerical simulation of ...

The authors study theoretically the electrostatic equilibria for a shell filled with a suspension of polyions (e.g., colloids, polyelectrolytes, etc.) and immersed in an infinite salt-free reservoir. The shell is treated as impermeable for polyions, but allowing free diffusion of counterions. From the solution of the linearized Poisson-Boltzmann equation we obtain the distribution of the potential ...

A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. ...

A preliminary design study of flight-type dc conduction-permanent magnetic, ac helical induction, and ac linear induction pumps for circulating 883 K (1130 F) NaK at 9.1 kg/sec (20 lb/sec) is described. Various electromagnetic pump geometrics are evaluate...

The general phenomenon of `induced-charge electro-osmosis' (ICEO) is described -- the nonlinear electro-osmotic slip caused by an applied field acting on induced ionic charge in the vicinity of a polarizable surface. A simple physical picture of the basic phenomenon is presented, and the ICEO flow around conducting cylinders and spheres in steady (DC), oscillitory ...

The overall efficiency of an ac electrically-driven fuel booster pump over a wide range of frequency has been reported in a general performance study. To find the effect of speed on the efficiency of the pump itself, the input-output characteristics of th...

The various technical solutions for solar powered pumping are presented and their feasibility examined: long shaft pumps, submerged motor pumps with DC, AC and electronic motors, and surface pumps. The equipment costs, installation, drilling costs, etc. a...

The primary focus of the paper is to establish both numerical and experimental methods to control the concentration of samples in a microreactor well. The concentration of the reacting samples is controlled by varying the initial sample size and electric field. Further, the paper numerically investigates the feasibility of mixing and reacting nanoliter samples with a wide variation in reaction ...

We consider the non linear electrophoretic transport of uncharged, ideally polarizable hydrodynamic Janus spheres, the inhomogeneity of which is produced by a variable Navier slip condition at the particle surface. A general, three dimensional formulation enabling calculation of the electrophoretic mobility of any patchy particle, with an arbitrary tensorial slip boundary condition is provided. ...

The ac free-electron laser (ac FEL) uses an ac (temporally oscillating but spatially uniform) field as the pump source with the hope that electromagnetic radiation will be produced with wavelength shorter than that can be generated by a conventional magnet FEL. The ac field can be provided by a ...

We report on experiments demonstrating the possibility to pump electrolyte solutions in closed microchannel loops using asymmetric arrays of micro-electrodes addressed with AC voltages. Velocities of a few mm/s can be obtained with voltages of a few Volts in this integrable pumping scheme. The variation of pumping ...

Electromagnetic ac conduction pumps for liquid metals perform better in a three-legged core structure. The physical principles are described, beginning with the transformer with a leakage yoke. The secondary current crosses the pump channel, and the chann...

://www.mof.go.jp/singikai/zaisanfollow_up/siryou/20080515/tepco.pdf CO2 Emission Reduction Potential of Heat Pump in Japan Drying Temp. rise AC Hot water AC water system Solar heat IT Network Household wall insulation Display Top runner appliances Next genSep. 24, 2009 Heat Pump Technology Development in Japan ...

distinctively ac features. The ac cones show a unique longitudinal growth that result in very high aspect ratio the pump. But even then, the cone growth continued until the meniscus became very slender and unstableAnomalous conical menisci under an ac field-departure from the dc Taylor cone Siddharth Maheshwari

For a dielectric solid surrounded by an electrolyte and positioned inside an externally biased parallel-plate capacitor, we study numerically how the resulting induced-charge electro-osmotic (ICEO) flow depends on the topology and shape of the dielectric solid. In particular, we extend existing conventional electrokinetic models with an artificial design field to describe the ...

This work considers the stability of an electro-osmotic microchannel flow with streamwise electrical conductivity gradients, a configuration common in microfluidic applications such as field amplified sample stacking. Previous work on such flows has focused on how streamwise conductivity gradients set a nonuniform electro-osmotic velocity which results in dispersion of the ...

... is a battery-operated suction pump for pharyngeal suctioning during resuscitation emergencies. Batteries are recharged by an ac charger included ...

... 47 6 Dimensions of the Wind Tunnel Components 48 7 Details of the Nozzle Throats 49 8 AC 27D Sliding Vane Vacuum Pumps 50 ...

bearings will be important in the development of micro- coolers, micropumps, microgenerators, and other

... One level of checking can be ac=orplished by recirculating A FFF concentrate through the proportioner pump and back into the tank; however, the ...

... Blood is drawn from the donor and into the system by the inlet pump during the collection process. AC and whole blood are mixed ...

In this paper, the authors present an isothermal, one-dimensional, steady-state model for a complete polymer electrolyte fuel cell (PEFC) with a 117 Nafion membrane. In this model the authors employ water diffusion coefficients electro-osmotic drag coefficients, water sorption isotherms, and membrane conductivities, all measured in their laboratory as functions of membrane ...

We present mesoscopic simulations of the counterion-induced electro-osmotic flow in different electrostatic coupling regimes. Two simulation methods are compared, dissipative particle dynamics (DPD) and coupled lattice-Boltzmann/molecular dynamics (LB/MD). A general mapping scheme to match DPD to LB/MD is developed. For the weak coupling regime, analytic expressions for the ...

Electronic paper is now developing fast into an accepted alternative for paper. Its applications nowadays seem focused on books, documents and newspapers. Development of credible color implementations of electrophoretic displays has been initiated, focusing on multi-layer in-plane electrophoresis, but the difficulties associated with these systems (particle drift, aperture, accuracy) were so far ...

The electro-osmotic drag coefficient of water in two polymer electrolytes was experimentally determined as a function of water activity and current density for temperatures up to 200 C. The results show that the electro-osmotic drag coefficient varies from 0.2 to 0.6 in Nafion{reg_sign}/H{sub 3}PO{sub 4} membrane electrolyte, but is essentially zero in phosphoric acid-doped PBI (polybenzimidazole) ...

Effects of Joule heating and the induced variable viscosity are considered for time-modulated electro-osmotic flow in a two-dimensional microchannel confined between two infinitely parallel plates. Analytical expressions for both temperature and velocity profiles are obtained through asymptotic expansions for thin Debye layers, providing expressions for both the velocity and ...

The report gives results of an experimental and theoretical investigation of the transient and steady state performance of a residential air-conditioning/heat pump (AC/HP) operating with different refrigerants. (NOTE: The project was motivated by environm...

The report gives results of an experimental and theoretical investigation of the transient and steady state performance of a residential air-conditioning/heat pump (AC/HP) operating with different refrigerants. (NOTE: The project was motivated by environmental concerns related to...

An evaluation of prospective laser materials for a space-based solar pumped laser system over the past decade has resulted in the identification of the iodine photodissociation laser as that system best suited to solar-pumped high energy operation. The ac...

It is important to generate fast fluid flow yet maintain low temperature rise for ac electrothermal (ac ET) pumping in microsystems with conductive fluids. This has been generally the limitation of ac ET driven micropump applications. We present an enhanced ac ET pumping ...

We are developing AC electrokinetic micropumps to drive electrically conductive biological fluids in microchannels. These pumps work on the principles of Induced Charge Electroosmosis (ICEO) and flow Field Effect Transistor (flowFET) phenomena. AC (as well as DC) electric fields can induce electrical double layer on a polarizable ...

Electroosmotic (EO) pumps based on dc electroosmosis is plagued by bubble generation and other electrochemical reactions at the electrodes at voltages beyond 1 V for electrolytes. These disadvantages limit their throughput and offset their portability advantage over mechanical syringe or pneumatic pumps. ac electroosmotic ...

-feet of water per year (ac-ft/yr). Similarly the well field is designed to pump 145,000 ac-ft/yr of groundwater. The project is proposed both to store water and pump groundwater. The proposal is to extract more groundwater table (the water table). Freshwater is supplied to the playas either as surface runoff in ...

potential for PDMS and glass with mixed phosphate-intralipid solution are nega- tive and positive directions). The ODT system was used to measure electro-osmotic flow of biological fluid in polymer and glass were pressed against two sub- strates (PDMS and glass) to form two different microchan- nels, glass

Electro-Osmotic Pulse Technology stops water intrusion through concrete. Water can enter a structure via seepage or through joints and cracks. Electrodes are installed in the concrete and the adjacent soil. A small voltage (up to 30 VDC) is applied betwee...

at any location along the capillary. In this work, we used electro- osmotic flow and glycerol as a model, glycerol (99%), sodium phosphate dibasic (Na2HPO4, 99%), and hydrofluoric acid (HF, 48%) were purchased by the Easypure-UV system from Barnstead (Dubuque, IA). The glycerol solutions were prepared by initially

The application of lattice-Boltzmann methods to electroviscous transport problems is discussed, generalising the moment propagation method for convective-diffusion problems. As a simple application, electro-osmotic flow in a parallel-sided slit is analysed, and the results compared favourably with available analytic solutions for this geometry.

are provided in subsequent sec- tions. Prior to chemical treatment, two 1/8 in. holes were drilled; accepted 26 January 2006; published online 7 March 2006 The purpose of this study is to investigate electro over the past few years, electro-osmotic flow involving free surfaces has yet to be studied in great

Bubbles can be trapped inside textured structures such as grooves, forming a superhydrophobic surface. A superhydrophobic surface has a large effective hydrodynamic slip length compared to a smooth hydrophobic surface and holds the promise of enhancing electrokinetic flows that find many interesting applications in microfluidics. However, recent theoretical studies suggested that electro-osmotic ...

Bubbles can be trapped inside textured structures such as grooves, forming a superhydrophobic surface. A superhydrophobic surface has a large effective hydrodynamic slip length compared to a smooth hydrophobic surface and holds the promise of enhancing electrokinetic flows that find many interesting applications in microfluidics. However, recent theoretical studies suggested that electro-osmotic ...

Chloride ion from bridge deck concrete can be removed by application of a direct current potential between bridge reinforcing steel(-) and a copper screen(+) conductor on the bridge surface. Soaring prices of all types of energy would make removal of all ...

The coupled-flow phenomenon, electro-osmosis, whereby water flow results from an applied electrical potential gradient, is being used at Lawrence Livermore National Laboratory to induce water flow through deep (25-40 meters below surface) fine-grained sed...

The earth covered magazines (ECMs) at many Army installations have severe moisture intrusion problems. This water intrusion causes deterioration and corrosion of ammunition and equipment within the ECMs, making many types of ordinance unusable, including ...

The influence of aqueous phase properties (pH, ionic strength and divalent metal ion concentration) on clay particle zeta potential and packed-bed electro-osmotic permeability was quantified. Although pH strongly altered the zeta potential of a Georgia kaolinite, it did not signi...

We present a visualization of the predicted instability in ionic conduction from a binary electrolyte into a charge selective solid. This instability develops when a voltage greater than critical is applied to a thin layer of copper sulfate flanked by a copper anode and a cation selective membrane. The current-voltage dependence exhibits a saturation at the limiting current. With a further ...

In this paper, a microfluidic-based chip with two straight microchannels and five branch microchannels was designed and tested to separate blood plasma from a small sample of fresh human blood. The electro-osmotic flow method was used to control the separation of blood plasma. Blood cell removal and blood plasma extraction were realized in experiments. The efficiency of extracting blood plasma can ...

We have developed 2 different micropumping methods for transporting ionic fluids through microchannels. The first method is based on Induced Charge Electroosmosis (ICEO) and AC flow field-effect. We used an AC electric field to produce a symmetric ICEO flow on a planar electrode, called `gate'. In order to break the symmetry of ICEO, we applied an ...

The paper describes briefly the following components of hydrogen-electric power drives: chilled hydrogen gas tank, liquid oxygen tank, fuel cell bank, dc/ac converter, ac drive motors, solid-state ac speed control, dc sputter-ion vacuum pumps, steam turbine generator, and steam condenser. Uses for the process steam ...

An AC Magnetohydrodynamic (MHD) micropump has been demonstrated in which the Lorentz force is used to propel an electrolytic solution along a microchannel etched in silicon. This micropump has no moving parts, produces a continuous (not pulsatile) flow, and is compatible with solutions containing biological specimens. micropump, using the Lorentz force as the ...

A computational study, employing a Floquet-transfer-matrix approach, of the current in a model two-step barrier diode under intense ac fields in the terahertz range is reported. It is demonstrated that the field pumps a net tunnel current through the structure, which can exhibit a negative differential resistance and whose direction can be controlled by ...

Recent experiments have demonstrated that AC electrokinetic micropumps permit integrable, local, and fast pumping (velocities � mm/s) with low driving voltage of a few volts only. However, they also displayed many quantitative and qualitative discrepancies with existing theories. We therefore extend the latter theories to account for three experimentally ...

We present the design, test and theoretical analysis of a novel micropump. The purpose is to make a pump with large flow rate (approximately 10 microL min-1) and high pressure capacity (approximately 1 bar) powered by a low voltage DeltaV<30 V. The pump is operated in AC mode with an electroosmotic actuator in connection with a full ...

The dynamics of the enolic form of acetylacetone (E-AcAc) was investigated using a femtosecond pump-probe experiment. The pump at 266 nm excited E-AcAc in the first bright state, S2(pi pi*). The resulting dynamics was probed by multiphoton ionization at 800 nm. It was investigated for 80 ps on the S2(pi pi*) and ...

Centrifugal pumps are generally sized to operate at or near the best efficiency point at maximum flow. The maximum flow requirements, however, frequently occur for a very short period during the operating cycle with the result that some method of flow control is required. The traditional approach to flow control has used valves which increase system pressure and inherently ...

The theory of the four main types of electromagnetic pumps for liquid metals, d-c conduction, a-c conduction, a-c induction, and travelling-field induction types, is reviewed. The four types are then analyzed to determine the factors which control performance, i.e., pump pressure, flow, and ...

Information learned from the investigative effort conducted in the solar-water-pumping systems portion of the Range Water System Improvement project is reviewed. The report covers the development of new windmill designs including fully counterbalanced, spring-counterbalanced and com-operated windmills, hydraulic system to replace pump rods of a ...

-air HVAC system, heat pump water heaters, a dehumidifying water heater, solid-state lighting, hybrid solar temperature cycles to test heat pump/AC equipment under quasi- field conditions. #12;www.ornl.gov Water Heater integrated heat pumps (IHPs). The goal is to produce a single appliance to provide space-conditioning, water

We report here for the first time the demonstration of self-pumped phase conjugation in photorefractive semiconductors using 1.32 micrometer light. Using an ac field technique to enhance the gain coefficient in InP:Fe and a single input pump beam, phase c...

This paper presents a system for continuous separation and transport of micron and submicron particles in fluidic environment based on dielectrophoretic fractionation in concert with AC electrothermal (AC ET)-induced fluidic pumping action. In this system, high frequency AC signals are used to energize asymmetric ...

This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the ...

Flow patterns with both recirculating and unidirectional characteristics are useful for controlled mixing and pumping within microfluidic devices. We have developed a fabrication process that converts injection-molded polymer chips into devices that demonstrate induced-charge electroosmosis (ICEO) effects (1,2) in AC fields. Polymeric insulating posts are ...

An electrostatically actuated micro peristaltic pump is reported. The micro pump is entirely surface micromachined using a multilayer parylene technology. Taking advantage of the multilayer technology, the micro pump design enables the pumped fluid to be isolated from the electric field. Electrostatic actuation of ...

Traditionally, fans and pumps have been designed to be capable of handling the maximum demand of the system in which they are installed. However, quite often the actual demand can vary and it can be much lower than the original design capacity. These situations have been corrected in the past through additions of outlet dampers to fans or throttling valves to ...

Some experimental results of the application of small electric fields on an optically pumped metal-dielectric far infrared (FIR) waveguide laser are shown. It is demonstrated that sizable modulation of the FIR output power can be obtained with ac fields.

We discuss the concept of local temperature for quantum systems driven out of equilibrium by ac pumps showing explicitly that it is the correct indicator for heat flow. We also show that its use allows for a generalization of the Wiedemann-Franz law.

Significant temperature and viscosity effects on the electrokinetic transport in a nanochannel with a slab geometry are demonstrated using a molecular dynamics (MD) model. A previously studied system consisting of Na^+ and Cl^- ions dissolved in water and confined between fixed crystalline silicon walls with negatively charged inner surfaces in an external electric field was investigated. ...

Significant temperature and viscosity effects on the electrokinetic transport in a nanochannel with a slab geometry are demonstrated using a molecular dynamics (MD) model. A previously studied system consisting of Na^+ and Cl^- ions dissolved in water and confined between fixed crystalline silicon walls with negatively charged inner surfaces in an external electric field was investigated. ...

Biomolecule gradients play an important role in the understanding of various biological processes. Typically, biological cells are exposed to linear and nonlinear concentration gradients and their response is studied for understanding cell growth, cell migration, and cell differentiation mechanisms. Recent studies have demonstrated the use of microfluidic devices for precise and stable ...

Biomolecule gradients play an important role in the understanding of various biological processes. Typically, biological cells are exposed to linear and nonlinear concentration gradients and their response is studied for understanding cell growth, cell migration, and cell differentiation mechanisms. Recent studies have demonstrated the use of microfluidic devices for precise and stable ...

Induced charge electro-osmotic (ICEO) flows depend crucially on a combination of diffuse layer charge build up and a non-trivial tangential electric field at the electrode surface. Moreover, since time-dependent fields are commonly used to drive ICEO flows, charging dynamics play a critical role in determining the magnitude and direction of the resulting fluid flow. ...

This paper presents and discusses techniques for energy conservation by reducing losses in ac motor driven systems, proposed by the technical community in response to surging cost of energy. An important aspect considered is the impact on electric utility systems in terms of harmonics and power factor of operation. The techniques evaluated in this paper are listed below. 1. ...

Numerical simulations were made of a micro-pump with step electrodes. An AC voltage was applied to each pair of step electrodes. The existing numerical studies using linear assumptions have a limitation that the theory is limited to low external voltage, at most 25mV. However, the present study took into account the Steric effect which is recognized as a ...

Electro-osmotic flow (EOF), where ions in the electric double layer (EDL) next to the wall are driven by an electric field, is commonly used in microfluidics. Experimental observations of the velocity deficit in the EDL within 250 nm of the wall in EOF of a monovalent aqueous electrolyte solution are reported and validated by analytical predictions. Unlike other techniques for ...

We show that nanoscale surface roughness, which commonly occurs on microfabricated metal electrodes, can significantly suppress electro-osmotic flows when excess surface conductivity is appreciable. We demonstrate the physical mechanism for electro-osmotic flow suppression due to surface curvature, compute the effects of varying surface conductivity and roughness amplitudes on ...

literature values for (62) Pirkle, W. H.; Readnour, R. S. Chromatographia 1991, 31, 129. (63) Lin, L.; Wu, C. Y.; Yan, Z. Q.; Yan, X. Q.; Su, X. L.; Han, H. M. Chromatographia 1998, 47, 689. Lim, H. J.; Lee, H. S.; Kim, I. W.; Chang, S. H.; Moon, S. C.; Kim, B. E.; Park, J. H. Chromatographia 1998, 48, 422

A compact high pressure hydraulic system having no moving parts for converting electric potential to hydraulic force and for manipulating fluids. Electro-osmotic flow is used to provide a valve and means to compress a fluid or gas in a capillary-based system. By electro-osmotically moving an electrolyte between a first position opening communication between a fluid inlet and ...

Chloride ion from bridge deck concrete can be removed by application of a direct current potential between bridge reinforcing steel (-) and a copper screen (+) conductor on the bridge surface. Soaring prices of all types of energy would make removal of all chloride prohibitatively expensive. The importance of verification of all electrical connections prior to the treatment is emphasized by the ...

A compact high pressure hydraulic system having no moving parts for converting electric potential to hydraulic force and for manipulating fluids. Electro-osmotic flow is used to provide a valve and means to compress a fluid or gas in a capillary-based system. By electro-osmotically moving an electrolyte between a first position opening communication between a fluid inlet and ...

The ability to generate complete, or almost complete, chaotic mixing is of great interest in numerous applications, particularly for microfluidics. For this purpose, we propose a strategy that allows us to quickly target the parameter values at which complete mixing occurs. The technique is applied to a time periodic, two-dimensional electro-osmotic flow with spatially and ...

, electroos- mosis provides an attractive means of pumping in microflu- idic devices. Electroosmosis refers., 2000, 2002; Gonza�lez et al., 2000). This AC electroosmosis method has the merit of low AC voltage to prompt chaotic advection utilizing induced-charge electroosmosis. In the present study, we examine

Irrigated crop production in the Texas High Plains is dependent on the Ogallala Aquifer, which has declined by up to 50 percent in some areas since irrigation development began in the 1930-40s. About 6.5 million ac-ft (8.0 x 109 m3) of water was pumped to irrigate 4.6 million ac (1.9 ha) in 2000, w...

pumps,18,19 or catalytic micropumps.20,21 Some of these micropumps, however, are difficult to fabricate. Alternating current (AC) field micropumps have been reported that create net flow over asymmetric electrode on both sides of the channel creates a micropump that is powered by the global AC field [Fig. 1(a

Heat pumps utilizing the magnetocaloric effect offer a potentially attractive alternative to conventional heat pumps and refrigerators. Many physical configurations of magnetic heat pumps are possible. Major classes include those requiring electrical energy input and those with mechanical energy input. Mechanical energy is used to move ...

Heat pumps utilizing the magnetocaloric effect offer a potentially attractive alternative to conventional heat pumps and refrigerators. Many physical configurations of magnetic heat pumps are possible. Major classes include those requiring electrical energy input and those with mechanical energy input. Mechanical energy is used to move ...

Prior research revealed that breast stimulation altered the way the lactating body handles alcohol. Its effects depended upon when it occurred relative to drinking. The goal of the present study was to determine whether breast pumping works independently of the physiological and metabolic changes that accompany lactation. To this end, we tested 12 women when they were ...

- fluidic devices.11,12 Alternatively, microfluidic flows have been driven by electroosmosis,13 occur during direct current (DC) electroosmosis.28 AC electro- hydrodynamic pumps, however, need Electroosmosis is induced by the interaction of ions in the electric double layer at the diode surface

A single-phase MHD relay is considered which is a module consisting of two working chambers with contact electrodes of a commutator network communicating through a conductive MHD pump. The device operates on a single-phase AC with a series connection of the channel and coil. It is filled with mercury and is connected to a secondary coil of a matching ...

For a symmetric bridge coupled to infinite leads, in the presence of a dipole-coupled external ac field with harmonic mixing, we solve the Schr�dinger equation in the time domain using open boundary conditions as well as in the energy domain using Floquet scattering theory. As this potential breaks parity and generalized parity, we find a nonvanishing average current. We ...

Attached is the completed Operation Test Procedure (OTP-200-004, Rev. A-18). OTP includes a print out of the Programmable Logic Controller (PLC) Ladder Diagram. Ladder Diagram was designed for installation in the PLC used to monitor and control pumping ac...

A microfluidic pump based on electroosmosis of the second kind was designed and fabricated. Experimental results using DC and AC voltages showed a close to second-order relationship between flow and voltage, in good agreement with theory. The experimental flow rates were considerably lower than the predicted maximum for the micropumps, which can be ...

Photovoltaic systems are economically viable in remote areas where grid power is not available and where power requirements are modest. PV systems provide power for water pumping, navigation aids, and residential electrification. Water pumping applications are projected to provide the largest market. The world's largest PV ...

This is a twenty-four month program on Coal Slurry Pump Development being conducted for the Department of Energy, Division of Coal Conversion, under Contract DE-AC03-79ET14842. The program consists of two phases. In the first phase an experimental prototype of a two-stage, high-pressure, centrifugal slurry pump will be fabricated and ...

A micropumping device has been developed, which may find application in different areas such as blood pumping and chemical reagents dosing in bioengineering or as an efficient thermal management solution scheme in space-constrained electronic devices, due to some of their unique properties such as lower noise generation and ease of miniaturization. In this presentation, liquid ...

Charge currents driven by the spin dynamics in the presence of the Rashba spin orbit interaction are investigated numerically. The spin current induced by the precession of the local magnetic moment can be converted to the charge current assisted by the spin orbit interaction. We use the recursive Green's function method and the Brouwer's formula for calculating the pumping ...

Recent experiments have demonstrated that ac electrokinetic micropumps permit integrable, local, and fast pumping (velocities �mm/s ) with low driving voltage of a few volts only. However, they also displayed many quantitative and qualitative discrepancies with existing theories. We therefore extend the latter theories to account for three ...

We present two different designs of electrohydrodynamic micropumps for microfluidic systems. The micropumps have no movable parts, and their simple design allows for fabrication by microsystems technology. The pumps are operated by ac voltages from 1to60V and were tested with aqueous solutions in the conductivity range of 1-112mSm?1 . The ...

We present two different designs of electrohydrodynamic micropumps for microfluidic systems. The micropumps have no movable parts, and their simple design allows for fabrication by microsystems technology. The pumps are operated by ac voltages from 1 to 60 V and were tested with aqueous solutions in the conductivity range of 1-112 mS m(-1). The ...