Engineering › Electrical and Electronic Engineering

Electrohydrodynamics and Fluid Dynamics

Works Count: 42550

Wikipedia

Description

This cluster of papers focuses on the use of electrohydrodynamic jet printing and electrospraying techniques for high-resolution printing, micro/nanoparticle encapsulation, and drug delivery applications. It explores the effects of electric fields, production of polymeric microspheres, and the use of ionic liquid ion sources in biomedical and nanotechnology applications.

Keywords

Electrohydrodynamic Jet Printing; Nanoparticle Encapsulation; Electrospraying; High-resolution Printing; Micro/Nanoparticles Production; Biomedical Applications; Drug Delivery; Electric Field Effects; Polymeric Microspheres; Ionic Liquid Ion Sources

Interfacial Forces in Aqueous Media

2006-05-22

Carel J. van Oss

Introduction PART I: THEORY Lifshitz-van der Waals (LW) Interactions Relation Between the Hamaker Constant and the Apolar Surface Tension Component Polar or Lewis Acid-Base Interactions Electrical Double Layer Interactions Brownian … Introduction PART I: THEORY Lifshitz-van der Waals (LW) Interactions Relation Between the Hamaker Constant and the Apolar Surface Tension Component Polar or Lewis Acid-Base Interactions Electrical Double Layer Interactions Brownian Movement Forces-Osmotic Interactions of Polymers Rate of Decay with Distance PART II: INTERFACIAL PROPERTIES AND STRUCTURE OF LIQUID WATER Lifshitz-van der Waals and Lewis Acid-Base Properties of Liquid Water-Physical and Physico-Chemical Effects Role of Water in Hydrophobic Attraction Role of Water in Hydrophilic Repulsion The Water-Air Interface PART III: EXPERIMENTAL MEASUREMENT METHODS Contact Angle and Surface Tension Determination and Preparation of Solid Surfaces Interfacial Tension Determination-Influence of Macroscopic- and Microscopic-Scale Interactions Different Approaches for Interpreting Contact Angles and Determining the Surface Tension and Surface Tension Components of Solids Electrokinetic Methods Direct Measurement Methods, Treating the Force Balance in Particular PART IV: ASSOCIATED PHENOMENA AND APPLICATIONS Surface Tension Components and Parameters of Liquids and Solids Attractive LW- and AB-Forces: Hydrophobic Interactions-Osmotic Pressures of PEO Solutions Repulsive AB-Forces: Hydrophilic Interactions The Primary and Secondary Interactions Phase Separation in Polymer Solutions Coacervation and Complex Coacervation Solubility of Polymers and Other Solutes Cell and Particle Stability Adsorption and Adhesion in Aqueous Media, Including Ligand-Receptor Interactions Kinetics and Energetics of Protein Adsorption onto Metal Oxide Surfaces List of Symbols Used References Index

Hydrophobic acceleration of Diels-Alder reactions

1980-12-01

Darryl Rideout , Ronald Breslow

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrophobic acceleration of Diels-Alder reactionsDarryl C. Rideout and Ronald BreslowCite this: J. Am. Chem. Soc. 1980, 102, 26, 7816–7817Publication Date (Print):December 1, 1980Publication History Published online1 May … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrophobic acceleration of Diels-Alder reactionsDarryl C. Rideout and Ronald BreslowCite this: J. Am. Chem. Soc. 1980, 102, 26, 7816–7817Publication Date (Print):December 1, 1980Publication History Published online1 May 2002Published inissue 1 December 1980https://pubs.acs.org/doi/10.1021/ja00546a048https://doi.org/10.1021/ja00546a048research-articleACS PublicationsRequest reuse permissionsArticle Views10094Altmetric-Citations1324LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Theory of space-charge-limited current enhanced by Frenkel effect

1970-02-01

Paul Murgatroyd

The theory of space-charge-limited current controlled by a single set of shallow traps is extended to allow for the reduction of the effective trap depth caused by high electric fields. … The theory of space-charge-limited current controlled by a single set of shallow traps is extended to allow for the reduction of the effective trap depth caused by high electric fields. This reduction, the Frenkel effect, may become appreciable in fields of a few kilovolts per centimetre. A current-voltage characteristic is given which, though following the Mott-Gurney Law at low fields, predicts much greater currents than given by this law at high fields.

Micro Flows: Fundamentals and Simulation

2002-07-01

GEM Karniadakis , Ali Beşkök , Mohamed Gad‐el‐Hak

Basic Concepts and Technologies * Governing Equations and Slip Models * Shear-Driven and Separated Micro Flows * Pressure-Driven Micro Flows: Slip Flow Regime * Pressure-Driven Flows: Transition and Free- Molecular … Basic Concepts and Technologies * Governing Equations and Slip Models * Shear-Driven and Separated Micro Flows * Pressure-Driven Micro Flows: Slip Flow Regime * Pressure-Driven Flows: Transition and Free- Molecular Regimes * Thermal Effects in Micro Scales * Prototype Applications of Gas Micro Flows * Electrokinetically-Driven Liquid Micro Flows * Numerical Methods for Continuous Simulation * Numerical Methods for Atomistic Simulation

View PDF Chat

The Electrical Discharge from Liquid Points, and a Hydrostatic Method of Measuring the Electric Intensity at Their Surfaces

1914-02-01

John Zeleny

View PDF Chat

Molecular Beams of Macroions

1968-09-01

Malcolm Dole , L. L. Mack , R. L. Hines +3 more

By means of electrospraying a dilute polymer solution into an evaporation chamber, negative macroions can be produced and a molecular beam formed by sampling the gaseous mixture of macroions, solvent, … By means of electrospraying a dilute polymer solution into an evaporation chamber, negative macroions can be produced and a molecular beam formed by sampling the gaseous mixture of macroions, solvent, and nitrogen molecules with a nozzle-skimmer system of the Kantrowitz–Gray type. The macroion current can be detected by a Faraday cage after the light ions have been repelled from the beam by negative voltages on a repeller grid. Theoretical repeller voltages which best agree with the observed are those calculated by assuming a macroion velocity within 2% of the estimated supersonic beam velocity of 743 m sec−1. Polystyrene macroions of 51 000 weight-average amu tend to form dimers and trimers in the beam while larger polystyrene macroions of 411 000 weight-average amu appear mostly to be multiply charged single species. The results demonstrate that definite mass/charge states can be formed by the electrospray technique, that a considerable monochromatization of macroion velocities in the beam takes place, and that the macroions become highly concentrated relative to low-molecular-weight solvent and nitrogen ions during the transit time in the supersonic beam.

Bending instability in electrospinning of nanofibers

2001-03-01

Alexander L. Yarin , Sureeporn Koombhongse , Darrell H. Reneker

A localized approximation was developed to calculate the bending electric force acting on an electrified polymer jet, which is a key element of the electrospinning process for manufacturing of nanofibers. … A localized approximation was developed to calculate the bending electric force acting on an electrified polymer jet, which is a key element of the electrospinning process for manufacturing of nanofibers. Using this force, a far reaching analogy between the electrically driven bending instability and the aerodynamically driven instability was established. Continuous, quasi-one-dimensional, partial differential equations were derived and used to predict the growth rate of small electrically driven bending perturbations of a liquid column. A discretized form of these equations, that accounts for solvent evaporation and polymer solidification, was used to calculate the jet paths during the course of nonlinear bending instability leading to formation of large loops and resulting in nanofibers. The results of the calculations are compared to the experimental data acquired in the present work. Agreement of theory and experiment is discussed.

Electrohydrodynamic spraying functioning modes: a critical review

1994-09-01

M. Cloupeau , B. Prunet–Foch

Micro/Nano Encapsulation via Electrified Coaxial Liquid Jets

2002-03-01

Ignacio G. Loscertales , Antonio Barrero , Ismael Guerrero +3 more

We report a method to generate steady coaxial jets of immiscible liquids with diameters in the range of micrometer/nanometer size. This compound jet is generated by the action of electro-hydrodynamic … We report a method to generate steady coaxial jets of immiscible liquids with diameters in the range of micrometer/nanometer size. This compound jet is generated by the action of electro-hydrodynamic (EHD) forces with a diameter that ranges from tens of nanometers to tens of micrometers. The eventual jet breakup results in an aerosol of monodisperse compound droplets with the outer liquid surrounding or encapsulating the inner one. Following this approach, we have produced monodisperse capsules with diameters varying between 10 and 0.15 micrometers, depending on the running parameters.

Current and droplet size in the electrospraying of liquids. Scaling laws

1997-03-01

Alfonso M. Gañán‐Calvo , Juan Dávila , Antonio Barrero

Biphasic Janus particles with nanoscale anisotropy

2005-09-25

Kyung‐Ho Roh , David C. Martin , Joerg Lahann

Electrohydraulic Discharge and Nonthermal Plasma for Water Treatment

2005-12-31

Bruce R. Locke , Masayuki Sato , P. Šunka +2 more

The application of strong electric fields in water and organic liquids has been studied for several years, because of its importance in electrical transmission processes and its practical applications in … The application of strong electric fields in water and organic liquids has been studied for several years, because of its importance in electrical transmission processes and its practical applications in biology, chemistry, and electrochemistry. More recently, liquid-phase electrical discharge reactors have been investigated, and are being developed, for many environmental applications, including drinking water and wastewater treatment, as well as, potentially, for environmentally benign chemical processes. This paper reviews the current status of research on the application of high-voltage electrical discharges for promoting chemical reactions in the aqueous phase, with particular emphasis on applications to water cleaning.

Fluorescence Activated Cell Sorting

1972-03-01

W. A. Bonner , H. R. Hulett , Richard G. Sweet +1 more

An instrument has been developed for sorting biological cells. The cells are rendered differentially fluorescent and incorporated into a small liquid stream illuminated by a laser beam. The cells pass … An instrument has been developed for sorting biological cells. The cells are rendered differentially fluorescent and incorporated into a small liquid stream illuminated by a laser beam. The cells pass sequentially through the beam, and fluorescent light from the cells gives rise to electrical signals. The stream is broken into a series of uniform size drops downstream of the laser. The cell signals are used to give appropriate electrostatic charges to drops containing the cells. The drops then pass between two charged plates and are deflected to appropriate containers. The system has proved capable of providing fractions containing large numbers of viable cells highly enriched in a particular functional type.

Electrostatic spinning of acrylic microfibers

1971-05-01

Peter K Baumgarten

Equilibrium configurations of rotating charged or gravitating liquid masses with surface tension. II

1974-02-01

S. Cohen , F. Plasil , W.J. Świa̧tecki

Microfluidics: Fluid physics at the nanoliter scale

2005-10-06

Todd M. Squires , Stephen R. Quake

Microfabricated integrated circuits revolutionized computation by vastly reducing the space, labor, and time required for calculations. Microfluidic systems hold similar promise for the large-scale automation of chemistry and biology, suggesting … Microfabricated integrated circuits revolutionized computation by vastly reducing the space, labor, and time required for calculations. Microfluidic systems hold similar promise for the large-scale automation of chemistry and biology, suggesting the possibility of numerous experiments performed rapidly and in parallel, while consuming little reagent. While it is too early to tell whether such a vision will be realized, significant progress has been achieved, and various applications of significant scientific and practical interest have been developed. Here a review of the physics of small volumes (nanoliters) of fluids is presented, as parametrized by a series of dimensionless numbers expressing the relative importance of various physical phenomena. Specifically, this review explores the Reynolds number Re, addressing inertial effects; the P\'eclet number Pe, which concerns convective and diffusive transport; the capillary number Ca expressing the importance of interfacial tension; the Deborah, Weissenberg, and elasticity numbers De, Wi, and El, describing elastic effects due to deformable microstructural elements like polymers; the Grashof and Rayleigh numbers Gr and Ra, describing density-driven flows; and the Knudsen number, describing the importance of noncontinuum molecular effects. Furthermore, the long-range nature of viscous flows and the small device dimensions inherent in microfluidics mean that the influence of boundaries is typically significant. A variety of strategies have been developed to manipulate fluids by exploiting boundary effects; among these are electrokinetic effects, acoustic streaming, and fluid-structure interactions. The goal is to describe the physics behind the rich variety of fluid phenomena occurring on the nanoliter scale using simple scaling arguments, with the hopes of developing an intuitive sense for this occasionally counterintuitive world.

View PDF Chat

Gas-Liquid Reactions

1970-01-01

P.V. Danckwerts , Arvo Lannus

Experimental characterization of electrospinning: the electrically forced jet and instabilities

2001-12-01

Yu-Shik Shin , Moses M. Hohman , Michael P. Brenner +1 more

Electrospinning process and applications of electrospun fibers

1995-08-01

Jayesh Doshi , Darrell H. Reneker

<scp>VORO++</scp>: A three-dimensional Voronoi cell library in C++

2009-10-27

Chris H. Rycroft

First Page First Page

View PDF Chat

Dripping to Jetting Transitions in Coflowing Liquid Streams

2007-08-28

Andrew S. Utada , Alberto Fernández‐Nieves , Howard A. Stone +1 more

A liquid forced through an orifice into an immiscible fluid ultimately breaks into drops due to surface tension. Drop formation can occur right at the orifice in a dripping process. … A liquid forced through an orifice into an immiscible fluid ultimately breaks into drops due to surface tension. Drop formation can occur right at the orifice in a dripping process. Alternatively, the inner fluid can form a jet, which breaks into drops further downstream. The transition from dripping to jetting is not understood for coflowing fluid streams, unlike the case of drop formation in air. We show that in a coflowing stream this transition can be characterized by a state diagram that depends on the capillary number of the outer fluid and the Weber number of the inner fluid.

View PDF Chat

Micropower generation using combustion: Issues and approaches

2002-01-01

A. Carlos Fernandez‐Pello

View PDF Chat

The effect of processing variables on the morphology of electrospun nanofibers and textiles

2001-01-01

Joseph M. Deitzel , James D. Kleinmeyer , Doug Harris +1 more

Studies in electrohydrodynamics. I. The circulation produced in a drop by an electric field

1966-04-05

Geoffrey Ingram Taylor

The elongation of a drop of one dielectric fluid in another owing to the imposition of an electric field has previously been studied assuming that the interface is uncharged and … The elongation of a drop of one dielectric fluid in another owing to the imposition of an electric field has previously been studied assuming that the interface is uncharged and the fluids at rest. For a steady field this is unrealistic, because however small the conductivity of either fluid the charge associated with steady currents must accumulate at the interface till the steady state is established. It is shown that equilibrium can only be established in a drop when circulations are set up both in the drop and its surroundings. A relation is found between the ratios of the conductivity, viscosity and dielectric constant for the drop and surrounding fluid which permits the drop to remain spherical when subjected to a uniform field. The streamlines of the circulation for this case are shown and criteria are given for distinguishing between circulations which carry the surface of the drop towards or away from the poles and for predicting whether the drop will become prolate or oblate. Experiments by S. G. Mason and his co-workers are compared with the theoretical predictions and agreement is found in all cases for which the necessary data are given.

Electrospraying route to nanotechnology: An overview

2008-01-30

A. Jaworek , A.T. Sobczyk

Principles of emulsion formation

1993-01-01

P. Walstra

The current emitted by highly conducting Taylor cones

1994-02-10

Juan Fernández de la Mora , Ignacio G. Loscertales

When a liquid meniscus held at the exit of a metallic capillary tube is charged to a high voltage V , the free surface often takes the form of a … When a liquid meniscus held at the exit of a metallic capillary tube is charged to a high voltage V , the free surface often takes the form of a cone whose apex emits a steady microjet, and thus injects a certain charge I and liquid volume Q per unit time into the surrounding gas. This work deals with liquids with relatively large conductivities K , for which the jet diameter d j is much smaller than the diameter d n of the capillary tube. In the limit d j / d n → 0, the structure of the jet ( d j and I , in particular) becomes independent of electrostatic parameters such as V or the electrode configuration, being governed mostly by the liquid properties and flow rate Q. Furthermore, the measured current is given approximately by I = f (ε) (γ QK /ε) ½ for a wide variety of liquids and conditions (ε, and γ are, respectively, the dielectric constant of the liquid and the coefficient of interfacial tension; f (ε) is shown in figure 11). The following explanation is proposed for this behaviour. Convection associated with the liquid flow Q transports the net surface charge towards the cone tip. This upsets the electrostatic surface charge distribution slightly at distances r from the apex large compared to a certain charge relaxation length λ, but substantially when r ∼ λ. When the fluid motion is modelled as a sink flow, λ is of the order of r * = ( Q εε 0 / K ) $\frac13$ (ε 0 is the electrical permittivity of vacuum). If, in addition, the surface charge density is described through Taylor's theory, the corresponding surface current convected towards the apex scales as I s ∼ (γ QK /ε) ½ , as observed for the spray current. The sink flow hypothesis is shown to be realistic for sufficiently small jet Reynolds numbers. In a few photographs of ethylene glycol cone jets, we find the rough scaling d j ∼ 0.4 r * for the jet diameter, which shows that the jet forms as soon as charge relaxation effects set in. In the limit ε [Gt ] 1, an upper bound is found for the convected current at the virtual cone apex, which accounts for only one-quarter of the total measured spray current. The rest of the charge must accordingly reach the head of the jet by conduction through the bulk.

Taylor cone and jetting from liquid droplets in electrospinning of nanofibers

2001-11-01

Alexander L. Yarin , Sureeporn Koombhongse , Darrell H. Reneker

Sessile and pendant droplets of polymer solutions acquire stable shapes when they are electrically charged by applying an electrical potential difference between the droplet and a flat plate, if the … Sessile and pendant droplets of polymer solutions acquire stable shapes when they are electrically charged by applying an electrical potential difference between the droplet and a flat plate, if the potential is not too large. These stable shapes result only from equilibrium of the electric forces and surface tension in the cases of inviscid, Newtonian, and viscoelastic liquids. In liquids with a nonrelaxing elastic force, that force also affects the shapes. It is widely assumed that when the critical potential φ0* has been reached and any further increase will destroy the equilibrium, the liquid body acquires a conical shape referred to as the Taylor cone, having a half angle of 49.3°. In the present work we show that the Taylor cone corresponds essentially to a specific self-similar solution, whereas there exist nonself-similar solutions which do not tend toward a Taylor cone. Thus, the Taylor cone does not represent a unique critical shape: there exists another shape, which is not self-similar. The experiments of the present work demonstrate that the observed half angles are much closer to the new shape. In this article a theory of stable shapes of droplets affected by an electric field is proposed and compared with data acquired in our experimental work on electrospinning of nanofibers from polymer solutions and melts.

Bending instability of electrically charged liquid jets of polymer solutions in electrospinning

2000-05-01

Darrell H. Reneker , Alexander L. Yarin , Hao Fong +1 more

Nanofibers of polymers were electrospun by creating an electrically charged jet of polymer solution at a pendent droplet. After the jet flowed away from the droplet in a nearly straight … Nanofibers of polymers were electrospun by creating an electrically charged jet of polymer solution at a pendent droplet. After the jet flowed away from the droplet in a nearly straight line, it bent into a complex path and other changes in shape occurred, during which electrical forces stretched and thinned it by very large ratios. After the solvent evaporated, birefringent nanofibers were left. In this article the reasons for the instability are analyzed and explained using a mathematical model. The rheological complexity of the polymer solution is included, which allows consideration of viscoelastic jets. It is shown that the longitudinal stress caused by the external electric field acting on the charge carried by the jet stabilized the straight jet for some distance. Then a lateral perturbation grew in response to the repulsive forces between adjacent elements of charge carried by the jet. The motion of segments of the jet grew rapidly into an electrically driven bending instability. The three-dimensional paths of continuous jets were calculated, both in the nearly straight region where the instability grew slowly and in the region where the bending dominated the path of the jet. The mathematical model provides a reasonable representation of the experimental data, particularly of the jet paths determined from high speed videographic observations.

Nanometre diameter fibres of polymer, produced by electrospinning

1996-09-01

Darrell H. Reneker , Iksoo Chun

Electrospinning uses electrical forces to produce polymer fibres with nanometre-scale diameters. Electrospinning occurs when the electrical forces at the surface of a polymer solution or melt overcome the surface tension … Electrospinning uses electrical forces to produce polymer fibres with nanometre-scale diameters. Electrospinning occurs when the electrical forces at the surface of a polymer solution or melt overcome the surface tension and cause an electrically charged jet to be ejected. When the jet dries or solidifies, an electrically charged fibre remains. This charged fibre can be directed or accelerated by electrical forces and then collected in sheets or other useful geometrical forms.

Ultrasonic Atomization of Liquids

1962-01-01

Robert J. Lang

An experimental study was made of the mechanism by which the ultrasonic vibration of liquid surfaces causes atomization. At exciting frequencies in the range of 10 to 800 kc, uniform … An experimental study was made of the mechanism by which the ultrasonic vibration of liquid surfaces causes atomization. At exciting frequencies in the range of 10 to 800 kc, uniform patterns of crossed capillary waves were found on the liquid surface when atomization occurred. The number-median diameter of the particles produced was found to be a constant fraction, 0.34, of the capillary wavelength; the capillary wavelength is calculable by Kelvin's equation using the exciting frequency and properties of the fluid being atomized. The evidence is strong that the mechanism of ultrasonic atomization involves the rupture of capillary surface waves and the subsequent ejection of the wave peaks from the surface as particles.

The formation of emulsions in definable fields of flow

1934-10-01

Geoffrey Ingram Taylor

The physical and chemical condition of emulsions of two fluids which do not mix has been the subject of many studies, but very little seems to be known about the … The physical and chemical condition of emulsions of two fluids which do not mix has been the subject of many studies, but very little seems to be known about the mechanics of the stirring processes which are used in making them. The conditions which govern the breaking up of a jet of one fluid projected into another have been studied by Rayleigh and others, but most of these studies have been concerned with the effect of surface tension or dynamical forces in making a cylindrical thread unstable so that it breaks into drops. The mode of formation of the cylindrical thread has not been discussed. As a rule in experimental work it has been formed by projecting one liquid into the other under pressure through a hole. It seems that studies of this kind which neglect the disruptive effect of the viscous drag of one fluid on the other, though interesting in themselves, tell us very little about the manner in which two liquids can be stirred together to form an emulsion. When one liquid is at rest in another liquid of the same density it assumes the form of a spherical drop. Any movement of the out er fluid (apart from pure rotation or translation) will distort the drop owing to the dynamical and viscous forces which then act on its surface. Surface tension, however, will tend to keep the drop spherical. When the drop is very small, or the liquid very viscous, the stresses due to inertia will be small compared with those due to viscosity.

Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws

2003-10-01

A. Castellanos , António Ramos , A. González +2 more

The movement and behaviour of particles suspended in aqueous solutions subjected to non-uniform ac electric fields is examined. The ac electric fields induce movement of polarizable particles, a phenomenon known … The movement and behaviour of particles suspended in aqueous solutions subjected to non-uniform ac electric fields is examined. The ac electric fields induce movement of polarizable particles, a phenomenon known as dielectrophoresis. The high strength electric fields that are often used in separation systems can give rise to fluid motion, which in turn results in a viscous drag on the particle. The electric field generates heat, leading to volume forces in the liquid. Gradients in conductivity and permittivity give rise to electrothermal forces and gradients in mass density to buoyancy. In addition, non-uniform ac electric fields produce forces on the induced charges in the diffuse double layer on the electrodes. This causes a steady fluid motion termed ac electro-osmosis. The effects of Brownian motion are also discussed in this context. The orders of magnitude of the various forces experienced by a particle in a model microelectrode system are estimated. The results are discussed in relation to experiments and the relative influence of each type of force is described.

View PDF Chat

Experimental investigation of the governing parameters in the electrospinning of polymer solutions

2004-02-05

S.A. Theron , Eyal Zussman , Alexander L. Yarin

Nanocapsule formation by interfacial polymer deposition following solvent displacement

1989-10-01

Hatem Fessi , F. Puisieux , J.P. Devissaguet +2 more

High-resolution electrohydrodynamic jet printing

2007-08-05

Jang‐Ung Park , Matthew T. Hardy , Seong Jun Kang +7 more

ELECTROHYDRODYNAMICS: The Taylor-Melcher Leaky Dielectric Model

1997-01-01

D. A. Saville

▪ Abstract Electrohydrodynamics deals with fluid motion induced by electric fields. In the mid 1960s GI Taylor introduced the leaky dielectric model to explain the behavior of droplets deformed by … ▪ Abstract Electrohydrodynamics deals with fluid motion induced by electric fields. In the mid 1960s GI Taylor introduced the leaky dielectric model to explain the behavior of droplets deformed by a steady field, and JR Melcher used it extensively to develop electrohydrodynamics. This review deals with the foundations of the leaky dielectric model and experimental tests designed to probe its usefulness. Although the early experimental studies supported the qualitative features of the model, quantitative agreement was poor. Recent studies are in better agreement with the theory. Even though the model was originally intended to deal with sharp interfaces, contemporary studies with suspensions also agree with the theory. Clearly the leaky dielectric model is more general than originally envisioned.

Dynamics of Drop Deformation and Breakup in Viscous Fluids

1994-01-01

Howard A. Stone

This article describes the dynamics of drop deformation and breakup in viscous flows at low Reynolds numbers. An attempt has been made to bring together a wide range of studies … This article describes the dynamics of drop deformation and breakup in viscous flows at low Reynolds numbers. An attempt has been made to bring together a wide range of studies in the drop deformation literature, as well as to provide a large number of references to potential applications. In particular, a summary is provided of experimental, numerical, and theoretical investigations that examine drop breakup in externally imposed flows, e.g. uniaxial extensional fluid motion or more complicated time-periodic flows. For well-characterized flow conditions that lead to breakup, the effects of flow and material parameters on the drop size distribution are summarized. Also, a short discussion is given of the stability of the shapes of translating drops. The subject of deformation of neutrally buoyant drops in viscous shear flows at low particle Reynolds numbers was summarized by Acrivos ( 1983) and was reviewed in this series by Rallison ( 1 984). The Acrivos and Rallison papers present (a) theoretical descriptions of steady, nearly spheri cal shapes and steady, long slender shapes, (b) a description of efficient boundary integral numerical methods, and (e) a summary of the experi mental work performed prior to 1984. As documented in these review articles, many of the important ideas necessary for understanding drop

Physics of Electric Propulsion

1969-09-01

R. G. Jahn , F. A. Lyman

Book on physics of electric propulsion covering gas acceleration principles, flow heating and space thrustor design Book on physics of electric propulsion covering gas acceleration principles, flow heating and space thrustor design

View PDF Chat

Electrospinning and electrically forced jets. I. Stability theory

2001-08-01

Moses M. Hohman , Michael Shin , Gregory C. Rutledge +1 more

Electrospinning is a process in which solid fibers are produced from a polymeric fluid stream (solution or melt) delivered through a millimeter-scale nozzle. The solid fibers are notable for their … Electrospinning is a process in which solid fibers are produced from a polymeric fluid stream (solution or melt) delivered through a millimeter-scale nozzle. The solid fibers are notable for their very small diameters (&lt;1 μm). Recent experiments demonstrate that an essential mechanism of electrospinning is a rapidly whipping fluid jet. This series of papers analyzes the mechanics of this whipping jet by studying the instability of an electrically forced fluid jet with increasing field strength. An asymptotic approximation of the equations of electrohydrodynamics is developed so that quantitative comparisons with experiments can be carried out. The approximation governs both long wavelength axisymmetric distortions of the jet, as well as long wavelength oscillations of the centerline of the jet. Three different instabilities are identified: the classical (axisymmetric) Rayleigh instability, and electric field induced axisymmetric and whipping instabilities. At increasing field strengths, the electrical instabilities are enhanced whereas the Rayleigh instability is suppressed. Which instability dominates depends strongly on the surface charge density and radius of the jet. The physical mechanisms for the instability are discussed in the various possible limits.

Electrically driven jets

1969-12-02

Geoffrey Ingram Taylor

Fine jets of slightly conducting viscous fluids and thicker jets or drops of less viscous ones can be drawn from conducting tubes by electric forces. As the potential of the … Fine jets of slightly conducting viscous fluids and thicker jets or drops of less viscous ones can be drawn from conducting tubes by electric forces. As the potential of the tube relative to a neighbouring plate rises, viscous fluids become nearly conical and fine jets come from the vertices. The potentials at which these jets or drops first appear was measured and compared with calculations. The stability of viscous jets depends on the geometry of the electrodes. Jets as small as 20 μm in diameter and 5 cm long were produced which were quite steady up to a millimetre from their ends. Attempts to describe them mathematically failed. Their stability seems to be due to mechanical rather than electrical causes, like that of a stretched string, which is straight when pulled but bent when pushed. Experiments on the stability of water jets in a parallel electric field reveal two critical fields, one at which jets that are breaking into drops become steady and another at which these steady jets become unsteady again, without breaking into drops. Experiments are described in which a cylindrical soap film becomes unstable under a radial electric field. The results are compared with calculations by A. B. Basset and after a mistake in his analysis is corrected, agreement is found over the range where experiments are possible. Basset’s calculations for axisymmetrical disturbances are extended to those in which the jet moves laterally. Though this is the form in which the instability appears, calculations about uniform jets do not seem to be relevant. In an appendix M. D. Van Dyke calculates the attraction between a long cylinder and a perpendicular plate at a different potential.

Disintegration of water drops in an electric field

1964-07-28

Geoffrey Ingram Taylor

The disintegration of drops in strong electric fields is believed to play an important part in the formation of thunderstorms, at least in those parts of them where no ice … The disintegration of drops in strong electric fields is believed to play an important part in the formation of thunderstorms, at least in those parts of them where no ice crystals are present. Zeleny showed experimentally that disintegration begins as a hydrodynamical instability, but his ideas about the mechanics of the situation rest on the implicit assumption that instability occurs when the internal pressure is the same as that outside the drop. It is shown that this assumption is false and that instability of an elongated drop would not occur unless a pressure difference existed. When this error is corrected it is found that a drop, elongated by an electric field, becomes unstable when its length is 1.9 times its equatorial diameter, and the calculated critical electric field agrees with laboratory experiments to within 1 %. When the drop becomes unstable the ends develop obtuse-angled conical points from which axial jets are projected but the stability calculations give no indication of the mechanics of this process. It is shown theoretically that a conical interface between two fluids can exist in equilibrium in an electric field, but only when the cone has a semi-vertical angle 49.3°. Apparatus was constructed for producing the necessary field, and photographs show that conical oil/water interfaces and soap films can be produced at the calculated voltage and that their semi-vertical angles are very close to 49.3°. The photographs give an indication of how the axial jets are produced but no complete analytical description of the process is attempted.

THE TERMINAL VELOCITY OF FALL FOR WATER DROPLETS IN STAGNANT AIR

1949-08-01

Ross Gunn , Gilbert D. Kinzer

The terminal velocities for distilled water droplets falling through stagnant air are accurately determined. More than 1500 droplets of mass from 0.2 to 100,000 micrograms, embracing droplets so small that … The terminal velocities for distilled water droplets falling through stagnant air are accurately determined. More than 1500 droplets of mass from 0.2 to 100,000 micrograms, embracing droplets so small that Stokes' law is obeyed up to and including droplets so large that they are mechanically unstable, were measured by a new method employing electronic techniques. An apparatus for the production of electrically charged artificial water droplets at a controllable rate is described. The over-all accuracy of the mass-terminal-velocity measurements is better than 0.7 per cent.

View PDF Chat

Nanoemulsions: formation, structure, and physical properties

2006-09-29

Thomas G. Mason , James N. Wilking , Kieche Meleson +2 more

We summarize procedures for producing 'nanoemulsions' comprised of nanoscale droplets, methods for controlling the droplet size distribution and composition, and interesting physical properties of nanoemulsions. In contrast to more common … We summarize procedures for producing 'nanoemulsions' comprised of nanoscale droplets, methods for controlling the droplet size distribution and composition, and interesting physical properties of nanoemulsions. In contrast to more common microscale emulsions, nanoemulsions exhibit optical transparency at high droplet volume fractions, ϕ, surprisingly strong elasticity at low ϕ, and enhanced diffusive transport and shelf stability. For these reasons, nanoemulsions have great potential in a wide range of industries including pharmaceuticals, foods, and personal care products.

Atomization and Sprays

1988-12-01

Arthur H. Lefebvre

Atomization and Sprays examines the atomization of liquids and characteristics of sprays. It explains the physical processes of atomization as well as guidelines for designing atomizers. In addition, it demonstrates … Atomization and Sprays examines the atomization of liquids and characteristics of sprays. It explains the physical processes of atomization as well as guidelines for designing atomizers. In addition, it demonstrates how the importance of the size and velocity of a particle contributes to improved spray characterization. Coverage includes general co

Physicochemical Hydrodynamics

1963-09-01

L Howarth

This is an interesting, important and, in parts, infuriating book. It brings together a number of disciplines in which convective processes (and thus fluid mechanics) play a fundamental role. This is an interesting, important and, in parts, infuriating book. It brings together a number of disciplines in which convective processes (and thus fluid mechanics) play a fundamental role.

Evaporation from drops : Part II

1952-01-01

W. E. Ranz

Scaleup of Nano/Micro Emulsions

2025-06-25

Aliasgar Shahiwala | CRC Press eBooks

Study of the satellite droplet formation in piezoelectric jetting at short nozzle-to-substrate distances

2025-06-24

Chaoyang Wang , Xiaotao Han , Di Zuo +4 more | Meccanica

High-resolution direct thrust characterization of electrospray thrusters with EMI-BF4 at different temperatures and polarities

2025-06-23

O. Neunzig , Paulo Lozano , Martin Tajmar | Journal of Electric Propulsion

Emerging Advances in Femtosecond Laser‐Designed Underwater “Aerofluidic” Systems: Concept, Design Principle, and Potential Applications

2025-06-23

Jiale Yong , Xianghuang Mei , Yang Cheng +5 more | Advanced Functional Materials

Abstract Traditional microfluidic technology predominantly focuses on the actuation, transport, and manipulation of liquids, whereas the manipulation of gases at the microscale has received limited attention. Analogous to liquid microfluidics, … Abstract Traditional microfluidic technology predominantly focuses on the actuation, transport, and manipulation of liquids, whereas the manipulation of gases at the microscale has received limited attention. Analogous to liquid microfluidics, the emerging field of “aerofluidics” focuses on the precise control and manipulation of tiny gases at microscopic scales, enabling the creation of highly integrated systems through gas‐gas or gas‐liquid interactions. This review systematically summarizes the fundamental concepts, design strategies, and achieved functions and applications of underwater aerofluidics, with femtosecond laser microfabrication serving as a key illustrative example. First, the fundamental theory of surface wettability is presented as the relevant background. Additionally, femtosecond laser microfabrication and its application in the design of surface superwettability and macroscopic bubble manipulation are introduced. Then, strategies for designing 2D and 3D underwater aerofluidic structures, as well as the physical mechanism of self‐driven gas transport, are discussed. The next section shows a variety of gas manipulation functions and applications achieved on the designed underwater aerofluidic systems, including gas merging, gas accumulation, gas division, gas patterning, and gas‒gas/gas‒liquid microreactions. Finally, the current progress, existing limitations, and future development directions in this emerging field are summarized and discussed.

Machine Learning technique to simulate the impact of nonlinear thermal radiation and electric field on hydrothermal features of dielectric nano-suspension

2025-06-23

Ahmed M. Galal , Rujda Parveen , Amjad Ali Pasha +7 more | Journal of the Taiwan Institute of Chemical Engineers

Agricultural Electrostatic Spraying Electrode Corrosion Degradation Mechanisms: A Multi-Parameter Coupling Model

2025-06-23

Yufei Li , Ailan Zou , Jun Hu +5 more | Agriculture

As an innovative plant protection method in precision agriculture, electrostatic spray technology can increase the droplet coverage area by over 30% coMpared to conventional spraying. This technology not only achieves … As an innovative plant protection method in precision agriculture, electrostatic spray technology can increase the droplet coverage area by over 30% coMpared to conventional spraying. This technology not only achieves higher droplet deposition density and coverage but also enables water and pesticide savings while reducing environmental pollution. This study, combining theoretical analysis with experimental validation, reveals the critical role of electrode material selection in induction-based electrostatic spray systems. Theoretical analysis indicates that the Fermi level and work function of electrode materials fundamentally determine charge transfer efficiency, while corrosion resistance emerges as a key parameter affecting system durability. To elucidate the effects of different electrode materials on droplet charging, a coMparative study was conducted on nickel, copper, and brass electrodes in both pristine and moderately corroded states based on the corrosion classification standard, using a targeted mesh-based charge-to-mass measurement device. The results demonstrated that the nickel electrode achieved a peak charge-to-mass ratio of 1.92 mC/kg at 10 kV, which was 8.5% and 11.6% higher than copper (1.77 mC/kg) and brass (1.72 mC/kg), respectively. After corrosion, nickel exhibited the smallest reduction in the charge-to-mass ratio (19.2%), significantly outperforming copper (40.2%) and brass (21.6%). Droplet size analysis using a Malvern Panalytical Spraytec spray particle analyzer (measurement range: 0.1–2000 µm) further confirmed the atomization advantages of nickel electrodes. The volume median diameter (Dv50) of droplets produced by nickel was 4.2–8 μm and 6.8–12.3 um smaller than those from copper and brass electrodes, respectively. After corrosion, nickel showed a smaller increase in droplet size spectrum inhomogeneity (24.5%), which was lower than copper (30.4%) and brass (25.8%), indicating superior droplet uniformity. By establishing a multi-factor predictive model for spray droplet size after electrode corrosion, this study quantifies the correlation between electrode characteristics and spray performance metrics. It provides a theoretical basis for designing weather-resistant electrostatic spray systems suitable for agricultural pesticide application scenarios involving prolonged exposure to corrosive chemicals. This work offers significant technical support for sustainable crop protection strategies.

Phase-separating enzyme-responsive condensates for inhalable delivery of biomacromolecules

2025-06-23

Yang Xiao , Shuang Zhou , Zhu Ting +6 more | bioRxiv (Cold Spring Harbor Laboratory)

Inhaled delivery of biomacromolecules shows extensive promise for treating a large variety of diseases, especially pulmonary and respiratory diseases. Although nanoparticle-based vehicles enhance intracellular uptake efficiency, it still remains challenging … Inhaled delivery of biomacromolecules shows extensive promise for treating a large variety of diseases, especially pulmonary and respiratory diseases. Although nanoparticle-based vehicles enhance intracellular uptake efficiency, it still remains challenging for biomacromolecules inhaled delivery to overcome cytotoxicity, cargo leakage and off-target effect. Here, we present an enzyme-responsive condensates based highly biocompatible and controllable platform for inhaled delivery of biomacromolecules. The condensates that can be modularly designed for rapid recruitment and enrichment of biomolecules, including Cas9 ribonucleoprotein (RNP) and mRNA, were internalized by cells via lysosomal-independent endocytosis, and subsequently released payloads triggered with endogenous physicochemical stimulus for controlled regulation of genes and proteins expression. Additionally, the micrometer sized condensates with highly structural and biological stability during lyophilization and nebulization enable inhalable delivery of biomacromolecules to lung. This condensate-based vehicle provides a promising platform for biomacromolecules inhaled delivery and controlled release, targeted cell regulation, and precise therapy.

Geometric optimization of coiled flow inverters to enhance biodiesel production using <scp>CFD</scp> and genetic algorithms

2025-06-23

Mahtab Izadi , Masoud Rahimi , Reza Beigzadeh +1 more | The Canadian Journal of Chemical Engineering

Abstract This study explores a novel approach to the geometric optimization of coiled flow inverters (CFIs) aimed at enhancing biodiesel production efficiency. By simulating nine distinct CFI geometries using advanced … Abstract This study explores a novel approach to the geometric optimization of coiled flow inverters (CFIs) aimed at enhancing biodiesel production efficiency. By simulating nine distinct CFI geometries using advanced computational fluid dynamics (CFD) and genetic algorithms (GA), this research introduces innovative methods for optimizing fluid flow characteristics. The CFD model yielded essential hydrodynamic data and friction factors, while oil conversion percentages for biodiesel were derived from existing literature. The integration of CFD results with experimental data significantly informed the GA optimization process, marking a key advancement in the field. Two new correlations were developed to predict friction factors and oil conversion percentages based on the coil length‐to‐diameter ratio, Reynolds number, and the number of 90° bends. This study uniquely identifies optimal geometries through a GA‐based multi‐objective approach, effectively balancing oil conversion and friction factor. Additionally, it delves into the trade‐offs between improving oil conversion and the resultant increase in pressure drop, highlighting the intricate complexities of fluid flow in CFIs and their implications for biodiesel production efficiency.

An installation for producing capsules by spraying

2025-06-21

M. M. Tashybayeva , Айтбек Какимов , Anara Bakiyeva +2 more | The Journal of Almaty Technological University

A gear pump and a centrifugal spray nozzle were used in the encapsulation unit. 0.8% and 1% sodium alginate were obtained for the encapsulated material. The capsules obtained in a … A gear pump and a centrifugal spray nozzle were used in the encapsulation unit. 0.8% and 1% sodium alginate were obtained for the encapsulated material. The capsules obtained in a concentration of 1% sodium alginate during the experiment were rounded and homogeneous, soft but stable under physical influence, and had an average diameter of 1,2×10 -3 м. To get one kilogram of mk capsules, it is necessary to take V z =1,404·10 -3 м 3 from the volume filled with capsules. This corresponds to the set productivity per hour. Turbulent motion is characterized by continuous mixing of liquid particles. Basically, transverse movements of particles moving longitudinally occur along the flow, the trajectories of which are very complex. Centrifugal nozzles are widely used in modern spray devices, which is explained by the simplicity of their design, reliability and efficiency of spraying. The main difference between a centrifugal nozzle and other types of sprayers is that the liquid passing through it is twisted, that is, it acquires a moment of magnitude relative to the axis of the nozzle. The pressurized liquid is pumped through the inlet channel into the torsion chamber, where it circulates intensively. The technological scheme of the installation is based on the operator's scheme. 𝑭𝒊 = 𝟎, 𝟑𝟒𝟑 for the number of significantly smaller degrees of freedom than in this table, F таб =1,02 the calculated values of the Fisher criterion were obtained as a result of calculations in the mathematical processor f 1 = 3, f 2 = 4 and the degree of significance α = 0,1 MathCad.

Continuous and scalable preparation of environmentally friendly controlled-release pesticide nanocapsules using low-energy-input microfluidics

2025-06-19

Ruixi Xiao , Zejun Cao , Bowen Yuan +4 more | Chemical Engineering Journal

Plasma-Induced Flow of De-Mineralised Water is Governed by the Aqueous Grounding Configuration

2025-06-18

Calum T. Ryan , M. Schalk , Anton A. Darhuber +2 more | Research Square (Research Square)

<title>Abstract</title> Plasma-induced liquid flow is a topic which is receiving accelerated interest in recent years as a possible method to controlthe distribution of reactive oxygen and nitrogen species through a … <title>Abstract</title> Plasma-induced liquid flow is a topic which is receiving accelerated interest in recent years as a possible method to controlthe distribution of reactive oxygen and nitrogen species through a liquid, thereby improving the efficiency of plasma-liquidinteractions. Here we demonstrate how the induced flow strength can be controlled by tuning the applied voltage of a systeminvolving a monopolar pulsed non-thermal helium atmospheric pressure plasma jet and de-mineralised water. A combination ofexperimental results and scaling laws demonstrate that in electrically floating liquids, the liquid flow is dominated by gas phaseEHD forces, whereas the dominant flow mechanism becomes less clear in electrically grounded liquids. The results of thisstudy therefore clearly show the important role the electrical grounding configuration plays in plasma-induced liquid flow.

Sustainable bubble mediated spray-antisolvent crystallization: precise size control and polymorph selection of glycine ultrafine particles

2025-06-18

Yingchen Wang , Jiaqi Luo , Qiutong Zhang +4 more | Food Chemistry

Dual-Plasma Discharge Tube for Synergistic Glioblastoma Treatment

2025-06-18

W. R. Murphy , Alex Horkowitz , Vikas Soni +2 more | Cancers

Glioblastoma (GBM) resists current therapies due to its rapid proliferation, diffuse invasion, and heterogeneous cell populations. We previously showed that a single cold atmospheric plasma discharge tube (DT) reduces GBM … Glioblastoma (GBM) resists current therapies due to its rapid proliferation, diffuse invasion, and heterogeneous cell populations. We previously showed that a single cold atmospheric plasma discharge tube (DT) reduces GBM viability via broad-spectrum electromagnetic (EM) emissions. Here, we tested whether two DTs arranged in a helmet configuration could generate overlapping EM fields to amplify the anti-tumor effects without thermal injury. The physical outputs of the single- and dual-DT setups were characterized by infrared thermography, broadband EM field probes, and oscilloscope analysis. Human U87-MG cells were exposed under the single or dual configurations. The viability was quantified with WST-8 assays mapped across 96-well plates; the intracellular reactive oxygen species (ROS), membrane integrity, apoptosis, and mitochondrial potential were assessed by multiparametric flow cytometry. Our additivity models compared the predicted versus observed dual-DT cytotoxicity. The dual-DT operation produced constructive EM interference, elevating electric and magnetic field amplitudes over a broader area than either tube alone, while temperatures remained <39 °C. The single-DT exposure lowered the cell viability by ~40%; the dual-DT treatment reduced the viability by ~60%, exceeding the additive predictions. The regions of greatest cytotoxicity co-localized with the zones of highest EM field overlap. The dual-DT exposure doubled the intracellular ROS compared with single-DT and Annexin V positivity, confirming oxidative stress-driven cell death. The out-of-phase operation of the discharge tubes enabled the localized control of the treatment regions, which can guide future treatment planning. Two synchronously operated plasma discharge tubes synergistically enhanced GBM cell killing through non-thermal mechanisms that coupled intensified overlapping EM fields with elevated oxidative stress. This positions modular multi-DT arrays as a potential non-invasive adjunct or alternative to existing electric-field-based therapies for glioblastoma.

Fluidic-manipulation-enabled multiplexed dose delivery of RONS by a CAP chip for dose optimization enhancement

2025-06-16

Fang Wang , Liangyu Zhou , Wei Guo +7 more | Microsystems & Nanoengineering

Enhancing Extrusion-Spheronization Pharmaceutical Production Efficiency: An AI-Driven Approach to Pellet Formulation and Manufacturing

2025-06-16

Saba Sareminia , Amin Najafi | Journal of Pharmaceutical Innovation

Design and Evaluation of a Novel Efficient Air-Assisted Hollow-Cone Electrostatic Nozzle

2025-06-16

Li Zhang , Zhi Li , Haibo Chu +3 more | Agriculture

For crop protection, electrostatic spraying technology significantly improves deposition uniformity and pesticide utilization through the “wraparound-adsorption” effect of charged droplets. However, existing electrostatic nozzles using hydraulic atomization suffer from low … For crop protection, electrostatic spraying technology significantly improves deposition uniformity and pesticide utilization through the “wraparound-adsorption” effect of charged droplets. However, existing electrostatic nozzles using hydraulic atomization suffer from low charge-to-mass ratios due to unclear principles for optimizing electrode parameters. To this end, this study designs and evaluates a novel air-assisted hydraulic-atomization hollow-cone electrostatic nozzle. First, the air-assisted hollow-cone nozzle was designed. High-speed imaging was then employed to obtain morphological parameters of the liquid film (length: 2.14 mm; width: 1.96 mm; and spray angle: 49.25°). Based on these parameters, an electric field simulation model of the electrostatic nozzle was established to analyze the influence of electrode parameters on the charging performance and identify the optimal parameter combination. Finally, feasibility and efficiency evaluation experiments were conducted on the designed electrostatic nozzle. The experimental results demonstrate that cross-sectional dimensions of the electrode exhibit a positive correlation with the surface charge density of the pesticide liquid film. In addition, optimal charging performance is obtained when the electrode plane coincides with the tangent plane of the liquid film leading edge. Based on these charging laws, the optimal electrode parameters were determined as follows: 2.0 × 2.0 mm cross-section with an electrode-to-nozzle tip distance of 3.8 mm. With these parameters, the nozzle achieved a droplet charge-to-mass ratio of 4.9 mC/kg at a charging voltage of 3.0 kV. These charged droplets achieved deposition coverages of 12.19%, 5.72%, and 5.91% on abaxial leaf surfaces in the upper, middle, and lower soybean canopies, respectively, which is a significant improvement in deposition uniformity. This study designed a novel air-assisted hollow-cone electrostatic nozzle, elucidated the optimization principles for annular induction electrodes, and achieved improved spraying performance. The findings contribute to enhanced pesticide application efficiency in crops, providing valuable theoretical guidance and technical references for electrostatic nozzle design and application.

Gestão da inovação e solução tecnológica de filtração para o problema do teor de água no diesel B s10 do norte do Brasil

2025-06-16

Eliomar Passos de Oliveira , Dimas José Lasmar , Everaldo de Queiroz Lima +2 more | OBSERVATÓRIO DE LA ECONOMÍA LATINOAMERICANA

Este trabalho apresenta a problemática referente ao teor de água presente no biodiesel e como os impactos diretos podem ser prejudiciais para a comercialização do diesel S10 B no Amazonas … Este trabalho apresenta a problemática referente ao teor de água presente no biodiesel e como os impactos diretos podem ser prejudiciais para a comercialização do diesel S10 B no Amazonas e mesmo na região norte do Brasil. Foram testados dois filtros escolhidos como os melhores no mercado, para integrarem um protótipo de filtro piloto para testar a redução do teor de água no diesel em situação da transferência do transporte para a armazenagem. Os testes foram realizados com uma mistura de 12% de biodiesel no filtro, percentagem que já torna o diesel fora dos limites recomendados pela Agência Nacional do petróleo – ANP. Os testes apresentaram uma eficiência de aproximadamente 50% de mitigação do teor de água no diesel, assegurando a garantia de segurança e qualidade do produto, em atendimento às diretrizes da Agência Nacional do Petróleo do Brasil.

Controlled Writhing of Chiral Matter in Deformable Droplet Confinement

2025-06-16

Rongjuan Liu , Xiaobin Dai , Benyou Li +4 more | Journal of the American Chemical Society

Chirality─the property of being nonsuperimposable on its mirror image─plays a fundamental role in shaping how materials interact with light, molecules, and external fields. This property is key to advancements in … Chirality─the property of being nonsuperimposable on its mirror image─plays a fundamental role in shaping how materials interact with light, molecules, and external fields. This property is key to advancements in areas such as quantum computing, flexible electronics, and smart sensors. However, controlling chirality in materials beyond the molecular scale has remained a significant challenge. In this study, we demonstrate a new approach for controlling the chirality of self-assembled materials by manipulating their behavior within deformable emulsion droplets. These droplets, ranging from nanometers to micrometers in size, guide the twisting of chiral fibrils formed through molecular self-assembly, with the droplet size determining the chirality. Our results, based on over 20 different chiral molecules, show that droplet confinement can induce chirality inversion, where nanoscale and microscale droplets exhibit opposite handedness. When the size of the droplet matches the persistence length of the chiral fibrils, the particles form superhelical structures. If mismatched, the fibrils twist in the opposite direction. In addition, we show that surfactant-coated helical fibrils can elongate into micrometer-long structures via living self-assembly, with chirality dictated by the as-formed helical fibrils and not the additional monomers. This work paves the way for new strategies to design and control chiral materials with tailored properties for a range of cutting-edge applications.

Dynamic Study on Synergy Mechanism and Characteristics of Particle Removal in Electrostatic Atomization

2025-06-16

Chenzi Teng , Yunhong Zhang , Sida Ren +1 more | Molecules

A laboratory-scale wire plate wet electrostatic precipitator was designed and constructed to investigate the particle enhancement and capture characteristics of electrostatically charged droplets in continuous atomization mode. A comparison was … A laboratory-scale wire plate wet electrostatic precipitator was designed and constructed to investigate the particle enhancement and capture characteristics of electrostatically charged droplets in continuous atomization mode. A comparison was made between different types of wet electrostatic precipitation mechanisms for particle removal, and the change mechanism of gas ionization mode under the action of charged droplets was analyzed. Experimental investigations were conducted on the effects of electrospray on corona discharge "ionic wind", as well as the force mechanism, agglomeration effect, and removal stability of particles under the synergistic action of electrostatic atomization and an electric field. The results demonstrated that electrospray mode could enhance the interaction between droplets and particles, promote the coagulation and accumulation of fine particles, increase their diameter to larger sizes that are easier to capture, and achieve high particle collection efficiency with significantly reduced water consumption while maintaining high corona current and particle capture effectiveness.

Iron nanoparticle-containing graphene oxide: synthesis and membrane properties

2025-06-15

T. Murshudov , A. Elshan , M. Asadov +3 more | Journal of Optoelectronic and Biomedical Materials

Graphene oxide (GO) layers were obtained by oxidation of graphite. Using iron oxide nanoparticles (FeNP) and GO and by GO reduction, a set of reduced nanocomposites FeNP@GO and FeNP@rGO were … Graphene oxide (GO) layers were obtained by oxidation of graphite. Using iron oxide nanoparticles (FeNP) and GO and by GO reduction, a set of reduced nanocomposites FeNP@GO and FeNP@rGO were obtained. Reduction of GO allowed additional functionalization of active centers in rGO. Control of the properties and structure of the formed nanocomposites was carried out by physicochemical methods (X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), chemical analysis). FeNP@GO and FeNP@rGO nanocomposites were used to remove harmful cations from water.

Exploring operational parameters and key characteristics in the extraction and purification of rubber tree (Hevea brasiliensis) seed protein using the hierarchical Osborne method and ultrafiltration technology

2025-06-15

Meiyu Zheng , Fenfen Lei , Lei Chen +7 more | LWT

A high performance aqueous surfactant solution for enhanced electrospray cooling

2025-06-14

Atul Ranjan , Rishav Kumar , Pradipta Kumar Panigrahi | International Journal of Heat and Mass Transfer

CFD and Experimental Comparison for Micro-Pump Performance in Space Applications: A Case Study

2025-06-12

Oana Dumitrescu , Cristian Dobromirescu , Valeriu Drăgan +2 more | Applied Sciences

This paper presents a case study comparing CFD predictions with experimental measurements for micropumps, with the goal of evaluating the accuracy and limitations of CFD methods in complex microscale geometries. … This paper presents a case study comparing CFD predictions with experimental measurements for micropumps, with the goal of evaluating the accuracy and limitations of CFD methods in complex microscale geometries. A fast design and evaluation methodology was developed, integrating linear design, 3D fully viscous CFD-based optimization, and rapid prototyping and testing. The main problem at this scale and configuration of pumps is the combination of Reynolds and Taylor numbers. Their impact on labyrinth performance prediction and therefore volumetric efficiency dominates the losses at this scale. Multiple CFD simulations were conducted using various turbulence models and solver settings, and results were compared against experimental data. The labyrinth region was simulated both independently and as part of the full pump assembly, with RANS and LES used for the former and RANS for the latter. Precision 3D-printed rotors and volutes were tested, and performance maps were obtained. Significant discrepancies between CFD and experiments were observed, which were reconciled using two empirical scaling coefficients for pressure and mass flow. These collapsed the CFD predictions onto the experimental data across all available speedlines. While the generalizability of these coefficients remains uncertain, the concept of using corrected scales, rather than other methods, seems to capture the macroscopic discrepancies between CFD and experiments.

Frontiers in Innovative Materials and Technologies for Oil–Water Separation

2025-06-12

Jikun Jiang , Sui Wan , Cheng Wen +2 more | Polymers

Oil-contaminated wastewater represents a major source of industrial pollution, posing significant risks to both the environment and human health. Traditional oil–water separation methods, including gravity separation, centrifugal separation, and air … Oil-contaminated wastewater represents a major source of industrial pollution, posing significant risks to both the environment and human health. Traditional oil–water separation methods, including gravity separation, centrifugal separation, and air flotation, are limited by their processing efficiency and scope of applicability. In recent years, innovative oil–water separation technologies have gained considerable attention, particularly those utilizing adsorption, filtration, and membrane separation, owing to their high efficiency and environmental sustainability. Separation materials derived from biomass substrates—such as cellulose, chitosan, and lignin—along with metal-based membranes and polymeric filters, have shown remarkable performance. This is especially true for superhydrophobic/superoleophilic and stimuli-responsive materials, which excel in separating complex emulsified oil systems. This paper provides a comprehensive overview of the strengths and limitations of current separation technologies and explores the potential applications of multifunctional materials in treating oil-contaminated wastewater, offering both theoretical insights and practical guidance for advancing green, efficient oil–water separation solutions.

Improvement of a microfilter prototype and its realization: chemical applications

2025-06-07

Tetyana Baydyk , Masuma Mammadovа , Graciela Velasco Herrera +1 more | Technology audit and production reserves

The object of this research is microfilters. This study aims to develop a microfilter that can be used, for example, for air or water filtration as traditional applications. The closed … The object of this research is microfilters. This study aims to develop a microfilter that can be used, for example, for air or water filtration as traditional applications. The closed indoor environments demand the control of the air quality for the health of humans who work there. The implementation of different technologies as MicroElectroMechanical Systems (MEMS), NanoElectroMechanical Systems (NEMS) and MicroEquipment Technology (MET) for microcomponents production is analyzed. The advantages and disadvantages of these technologies are described. MET was used to produce and develop microfilter structure. The structffure and model of the microfilter is presented. The problem to be solved is connected with microfilter structure simplification and preparation it for the use of new technologies for their production. For its realization the 3D printer was used. 3D printers are the equipment that realizes an additive technology that has been actively developed in recent years. From computer 3D model it is possible to build the 3D prototype. The essence of the results is the possibility of mass production of microfilters. Different possible applications, not only filtration of air and liquid are described, but applications in chemistry for microreactions module and microseparation units. It was compared new microfilter design with our previous prototype of microfilter developed and produced using the MET. The MET has advantage that it works with various materials and not just those used in microelectronics. Their tests and investigations demonstrated that the microfilters can be used in practice. New prototype was made by 3D printer. Comparative assessment of the first microfilter prototype and new prototype shows that the new prototype has a simplified structure and is easier to manufacture. One of the most interesting areas of their applications is for chemical microreactors. It is one of the new, interesting and promising areas of application.