Influence Of Electrical Forces Research Articles

Application of Electrosprayed Nanoparticles as Targeted Drug Delivery Systems: A Mini Review

Nanoparticles (NPs) are referred to as tiny materials in size ranging from 1 to 100 nm. Unique characteristics of the NPs, including small sizes and high surface area, appropriate reactivity, proper stability, great strength, and many more, have resulted in their wide use in numerous fields. Among different techniques reported for synthesizing the nanoparticles, electro-hydrodynamic atomization or electrospray has been identified as a well-practiced and high efficient technique for the formation of fine and homogenous NPs from a liquid under the influence of electrical forces. This process allows feasible encapsulation of different drugs, vitamins, and proteins applicable in the targeted drug delivery systems. Since the release rate of the loaded pharmaceutical materials could be easily tuned via varying the properties of core and shell components. Herein, we summarized the importance of the electrospray technique for the production of drug-loaded nanoparticles applicable in controlled drug delivery systems.

Mitigation of turbophoresis in particle-laden turbulent channel flows by using incident electric fields

The influence of electric forces on inertial particles in turbulent channel flows is explored using direct numerical simulations. It is found that the near-wall buildup of particle concentration due to turbophoresis can be reduced up to 2 orders of magnitude by imposing an ac electric field.

Study on the Dynamics of Tribocharged Coal and Mineral Particles in Free-Fall Triboelectric Separator

The dynamics of 2.0˜0.8 mm or 0.8˜0.5 mm size fraction of tribocharged organic coal, pyrite, and calcite particles were studied under the electric field using the high-speed dynamic camera combined with high-speed motion analysis system. Motion images of these particles were obtained and used to analyze their dynamic parameters. Organic coal particles tribocharged positively move to the negative plate, while pyrite and calcite particles reach the positive plate under the influence of electric force. These results indicate that the trajectories of all 2.0˜0.8 mm particles are similar to parabolic curves. For 0.8˜0.5 mm particles, the trajectories are approximate straight line, except for the calcite. The vertical velocities of all particles increase with a fluctuant acceleration as a result of gravity and drag force. The horizontal velocities of all particles vary slightly. The dynamics of 0.8˜0.5 mm particles prove that size is very important for the triboelectric separation. The actions of electric force and drag force are increased with the decrease of particle size.

Fiber Separation from Ground Corn Flour Using an Electrostatic Method

ABSTRACTCorn kernels contain 9% fiber by weight, which is not digested well by nonruminants such as chicken and swine. Also, fiber is nonreactive in the dry‐grind process for ethanol production and is considered as feedstock for the production of second‐generation bioethanol. Fiber separation can enhance starch concentration in animal feed and increase starch loading in ethanol plants. Electrostatic separation is used to separate particles from granular mixtures under the influence of electrical forces. The Elusieve process, a combination of sieving and air classification, separates fiber by taking advantage of differences in size, shape, and density. Differences in dielectric properties could also be exploited for fiber separation. The aim of this study was to evaluate the effectiveness of electrostatic separation of fiber particles from corn. When the electrostatic method was used in conjunction with Elusieve processing, the fiber product had higher neutral detergent fiber (NDF, 52.9%) compared with Elusieve processing alone (NDF of 40.5%). Also, a higher quantity of enhanced flour (95.0% yield) was produced when the electrostatic method was used in conjunction with Elusieve processing compared with Elusieve processing alone (93.0% yield), without any change in quality of the enhanced flour (NDF of 6.6% in both cases). The electrostatic method improved fiber separation when used in conjunction with Elusieve processing.

Producing Pharmaceutical Particles via Electrospraying with an Emphasis on Nano and Nano Structured Particles - A Review

Recent advances in nanotechnology offer nano sized or nanostructured pharmaceutical particles, being as small as the size of cells such as receptors or nucleic acids, which can be engineered to provide enhanced efficacy, solubility, or biocompatibility, and to administer at much lower dosages. However, industrial production of these particles is still challenging. Among different techniques, aerosol based ones might be favorable since they are considered as contamination free processes and do not interfere with complex molecules of drugs. We, in this review, consider liquid atomization, where droplet formation is followed by conversion into solid particles. The best candidate is a method, which not only produces mono sized droplets with a diameter smaller than the inside nozzle diameter but also generates small enough start up sizes. Such a method is found in: Electro-Hydrodynamic Atomization (EHDA) or Electrospraying. Electrospraying is now a well practiced technique for producing very fine monodisperse droplets from a liquid under the influence of electrical forces. By controlling the liquid flow rate and the electrostatic potential between the liquid and the counter electrode, droplets within a narrow size range can be generated, while the mean diameter ranges from nanometers up to several micrometers. Besides generating monodisperse droplets, electrosprays are also distinguished by their self dispersing nature due to Coulomb repulsion, the possibility of trajectory control of the produced charged droplets, and the reduced risk of nozzle clogging due to the large size of the orifice compared to the size of the droplets. We will discuss different spraying modes depending on the strength of the electric stresses relative to the surface tension stress on the liquid surface and on the inertia of the liquid leaving the nozzle. However, for the production of monodisperse nanoparticles the so called cone-jet mode will be explained in depth. Scaling laws can be used to estimate the operational conditions for producing nanodroplets of a certain size. Hartman and coworkers refined the scaling laws for EHDA in the Cone-Jet mode using theoretically derived models for the cone, jet, and droplet size. By means of several examples, a generic way to produce nanoparticles, via scaling laws, from a multitude of different precursors will be discussed. Several examples of medicine particles with different properties made by EHDA will be given. Processes based on bipolar coagulation, where oppositely charged carrier particles and nano sized active agents are brought together to form composite drugs, will be discussed. Finally some attention will be given to challenges on out-scaling of EHDA methods for industrial production.

The effect of electric current on the synthesis of single-walled carbon nanotubes by temperature controlled arc discharge

The effect of discharge current on the synthesis of single-walled carbon nanotubes (SWCNTs) was studied under controlled atmosphere at 500 °C by electric arc discharge. It was shown that the production rate of collected soot was increased but the purity of SWCNTs decreased with increasing discharge current. With a current of 100 A, the SWCNT was very uniform in diameter and a high purity rate of 55% was achieved, as shown by TEM and Raman spectra. Then the influence of electric force, discharge current and catalyst distribution on the formation of SWCNTs was also discussed.

On the gaseous nature of positive filamentary streamers in hydrocarbon liquids. II: Propagation, growth and collapse of gaseous filaments in pentane

This paper presents a study of the dynamics of positive streamer filaments in pentane using an optical method described in the text for pressures up to 9 MPa. It is observed that filaments expand and collapse, in a similar way to cavitation bubbles. Good agreement with the Rayleigh model shows that the dynamics of filaments is determined by liquid inertia. The influence of electric forces (electrostatic pressure) on the dynamics is found to be negligible. An evaluation of the energies involved shows that filaments are mainly composed of vapour, whose pressure varies with time and space and is on average higher than the hydrostatic pressure. Vaporization results mainly from energy dissipated at the filament extremity, which may be compared to a propagating point heat source of about 10 W power. At low pressure, a significant influence of energy dissipation within the filament, attributed to the transient current flowing during propagation, is also observed. At high pressure and/or high voltage, the stopping of the streamer is due to collapse of the gaseous filaments.

Hydrodynamics of dielectric fluid films

We introduce a general hydrodynamic model to study the stability of lipid films against thermal fluctuations. As one novel aspect the model accounts before all for a complete intrinsic surface rheology of the film interfaces. Thus the rheological behaviour of the surface adsorbed lipids is modelled which screen the hydrophobic film interior against the aqueous exterior. For coloured films we demonstrate first the influence of electrical forces on the dynamics and film stability. For that we perform a linear stability analysis on a simplified mechanically symmetric film with i) symmetric surface charge distribution and ii) linear electric potential drop across the film. Based on the complete film model we then categorize the complete set of solutions of the linearized equations of motion and we study the growth rates of unstable film modes. Finally we discuss the stability properties of a black film after introducing a repulsive mechanism due to the steric hindrance of the interfacial lipids.

Collection of inertialess particles on elliptical and irregular cylinders with electrical forces and gravitation

Particle trajectories and collection efficiencies are predicted for the collection of fine, inertialess, charged particles on a single elliptical-cylinder or ribbon collector in a gaseous flow field under the influence of electrical forces and gravitation. The two electrical forces considered are the coulombic-type force with a charged collector combined with the force due to a uniform external electric field directed at an arbitrary angle to the flow. Theory indicates the method of solution to be independent of the shape of the cylindrical collector. For any given collector geometry, results show that, under many conditions, the collection efficiency and deposition density are the same for a wide variety of stationary incompressible flows. With the coulombic force alone, particle collection is independent of both collector geometry and the flow field.

Collection of inertialess particles on circular cylinders with electrical forces and gravitation

Particle trajectories and collection efficiencies are predicted for the collection of fine, inertialess, charged particles on a single circular cylinder collector in a gaseous flow field under the influence of electrical forces and gravitation. The two electrical forces considered are the coulombic-type force with a charged collector combined with the force due to a uniform external electric field directed at an arbitrary angle to the flow. Analytical solutions reveal that the collection efficiency and deposition density of inertialess, charged, point particles under the influence of the forces are the same under many conditions and independent of the Reynolds number for a wide variety of flow velocity profiles, which includes potential, Oseen, and stationary-vortex flows. For cellular flow fields, fiber packing density is shown to have little effect on collection.

On the Collection Efficiency of Water Droplets under the Influence of Electric Forces I: Experimental, Charge-Multipole Effects

The collection efficiency of water droplets under the influence of electric forces was studied in simulation experiments for the case of a charge-induced multipole interaction. With the aid of an elaborate laboratory apparatus, the size increase of a charged droplet failing through a cloud of neutral, almost uniform small particles was determined, and an average collection efficiency deduced. The experimental results indicated efficiencies of one to two orders of magnitude greater than the values for neutral droplets under otherwise similar conditions. Likewise, the efficiencies were found to increase with the ratio of collected to collecting droplet sizes, and wore insensitive to variations of the electric charge of the particles.

Associated Learned Societies of Liverpool

THE triennial public exhibition and soirée organized by the Associated Learned Societies of Liverpool and District to illustrate the progress in science and education since their last exhibition in 1935 was held in the City Technical College on October 22. During the course of the exhibition, Prof. E. W. Marchant gave a lecture on “Television”, H. Ken-drick on “Changing India”, W. H. Watts on “The Moon”, D. Caradog Jones on “The Changing Population of Merseyside”, Prof. J. T. Craig on “Veterinary Pathology”, and a number of shorter talks were given in the individual rooms. The Institute of Chemistry and the Society of Chemical Industry exhibited process demonstrations of artificial silk spinning, products obtainable from cotton seed, demonstrations of the action of dirt particles under the influence of electrical forces, dyeing and armour-plate glass ; the British Association of Chemists exhibited a combined temperature and humidity recorder, smoke density determination apparatus and samples from the plastics industry. The Liverpool Biological Society's room included a demonstration exhibit by Prof. J. H. Orton on his Dee fisheries work, Dr. R. J. Daniel on pearl-formation, and Mrs. Bisbee on the ductless glands. Mr. Eric Hardy had arranged a special “Country-Side” Room with Nature films, photographs, habitat groups of British birds and mammals, bird migration ('ringing') and flight (bird-wing) displays, illuminated natural colour lantern slides, bird sanctuary devices and maps of local bird distribution. The exhibition also included natural colour films, an ingenious micro -projector by Mr. A. V. Wilkinson, Dr. Glynn Morris's geological collection, and in the Engineering Society's room, a trafficator for cyclists invented by Mr. A. Robins.

The diffusion of colloidal electrolytes and other charged colloids

Measurements of the diffusion of colloidal substances have frequently been used as a method for determining their particle size. The well-known Stokes-Einstein equation has generally been considered to give the relationship between the quantities. The influence of electrical forces in making the Stokes-Einstein equation inapplicable seems to have been almost generally neglected. Thus a considerable amount of work has been done on the diffusion of dyes and conclusions drawn using this equation about the particle size which, as shown in this paper, are quite unjustified. From such work a theory of dyeing with cotton substantive dyes has been built up. Freundlich in his text book points out that since dyes are electrolytes, the Nernst relation between the diffusion constant and the mobilities of the two ions composing the electrolyte, 1/D = 1/2RT (1/U + 1/V), (1) must be taken into account. He then adds, “We can, however, conclude from these measurements at what size of particle, at what value of diffusion constant therefore, a dissolved substance begins to behave like a colloid.” He does not, however, point out that this equation only applies to uni-univalent electrolytes. When the extended equation for multivalent electrolytes is used, then, as will be shown later, one cannot conclude even qualitatively what the particle size is. With the exception of Svedberg and Tiselius, who take the electrical forces into consideration in the case of sedimentation equilibrium, previous writers seem for the most part to have entirely neglected the matter. Thus the question is not dealt with at all in the 60 pages devoted to diffusion in von Hahn’s “Dispersoidanalyse.” Freundlich ( loc. cit. ) goes so far as to say, “Perhaps no method is more fruitful for the investigation of lyophilic sols than the measurement of diffusion . . . the only difficulty is that the measurements are tedious.” But, as we will explain, the electrical forces may also play a part in the diffusion of charged colloids not usually considered as “colloidal electrolytes” and give rise to unexpectedly high diffusion velocities. Since the time of Thomas Graham, low diffusion has been considered a characteristic of a colloid, and the possibility of a substance of several thousand “particle weight” having a diffusion coefficient of the same order as that of, for example, copper sulphate does not seem to have been realised. In this respect the recent striking experiments of Bruins on the diffusion of starch and gum arabic, as well as measurements of diffusion coefficients of dyes by one of us (C. R.), are of consideable interest.

Scientific Serials

Poggendorff's Annalen der Physik und Chemie, 1874, No. 12.—This number completes vol. 153 of the series, and contains the following papers:—On the capacity of liquids for conducting heat, by A. Winkelman; account of experiments based upon the same method which Stefan employed successfully for determining the heat-conducting capacity of air, and results tabulated for water, alcohol, bisulphide of carbon, glycerine, and solutions of chlorides of potassium and sodium.—On the elastic after-effects in torsion motions, by F. Neesen.—Experimental researches on the behaviour of non-conducting bodies under the influence of electric forces, by Ludwig Boltzmann. The author starts from the correct supposition that, according to the theories of Clausius, Maxwell, and Helmholtz on the behaviour of dielectric non-conductors in the electric field, the remarkable yet obvious consequence results (which seems to have been overlooked hitherto), that electric forces must necessarily exercise perceptible attraction upon non-conductors simply on account of their dielectric polarisation. The results he obtained were quite in correspondence with the theories his experiments were based upon.—On the action of electrophora, by P. Riess.—Critical remarks on electro-dynamics, by H. Helmholtz.—On the power of conducting electric currents in metallic sulphides, by Ferdinand Braun. This paper is a supplement to another one by Herr Herwig (vol. 153, No 9, of these Annals), on the behaviour of iron and steel rods in galvanic currents.—On the reflection of light from the two surfaces of a lens, by Dr. Krebs. It is a well-known fact, that when light passes through a lens and we neglect the absorption in the interior of the lens itself, a certain quantity of light is reflected by the surfaces of the lens. Dr. Krebs for the first time gives a mathematical account of this phenomenon.—On the apparent place of a luminous point situated in a denser transparent medium, or that observed through a so-called plane-parallel plate, by K. L. Bauer. The author arrives at the conclusion that in most works on physics, and especially on optics, misrepresentations of the point in question are contained, and quotes as examples the works of Mousson, Wüllner, Crüger, Müller, Riedel, Schabus, Krebs, Frick, Banitz, Weinhold, and Jochmann; the only praiseworthy exception he found was Harting's excellent work on the microscope.—On some new sulphur salts, by R. Schneider (tenth paper). The new salts mentioned in this paper are a compound of the formula— Na2S, Tl2S3 + Tl2S, Tl2S3 and another one of the formula Tl6S7.—On a new eye-piece, by Dr. H. Krüss. The author points out that the latest improvements in optical instruments generally applied to object-glasses, and that the eye-pieces remained where Huyghens and Ramsden left them; he therefore directed his attention to the improvement of eye-pieces, which he describes. Whether these improvements will answer their purpose, practical experiments only can show.—A note, by G. Wiedemann, on the dissociation of salts containing water. Mr. Wiedemann claims priority with regard to the investigations of M. Debray (Comptes Rendus, t. 66, p. 194, 1868).—A note on the theory of electricity, by E. Edlund.—A note by F. Lippich, on an electro-dynamic experiment of F. Zoellner, described in these Annals, vol. 153, p. 138.—A note by O. E. Meyer, on a paper by Dr. G. Baumgartner, on the influence of temperature upon the velocity of effluence of water flowing from tubes (these Annals, vol. 153, p. 44).—A note by H. Baumhauer, on a paper of Dr. F. Exner, on the solution-figures upon the surfaces of crystals (these Annals, vol. 153, p. 53). Mr. Baumhauer points out that these figures are quite independent of the crystallographic construction of the substances undergoing solution.—On the rays of light which decompose the xanthophyll of plants, by J. Wiesner. Finally, A. Gawalovski describes a self-acting mercury valve for shutting off gases, and preventing their passage in any but the desired direction.