Role Of Electrical Forces Research Articles

Role of Electrical Forces in Angiogenesis

The role of electrical forces in angiogenesis is widely studied. The electric field (EF) induces polarization of the endothelial cells, and in this way, it is a morphogen in angiogenesis. Additional to the polarization, it may build up by newborn cells in the process of cellular fission. Due to the weak direct experimental results on the transitions of endothelial cells, we used an analogy to these epithelial transitions. This involved using the injury current, which induces oriented cell migration and morphological arrangement in wound healing. The injury-current considerations are applied for malignant proliferation as well.

The Use of Electric Force as a Replacement of Buoyancy in Two-phase Flow

When an electrostatic field is applied to a medium, an electric force arises, originated by polarization and by the possible presence of free charge. If the medium is a two-phase fluid, this force drives the vapor (of lower dielectric permittivity) towards the zone of weaker electric field, giving the opportunity of separating phases and enhancing boiling heat transfer in microgravity conditions, where buoyancy is lacking. Electric force is also responsible for bubble deformation. In this paper, after a comprehensive description of electro-hydro-dynamics (EHD) mechanisms in a two-phase fluid, some relevant literature data about EHD-induced phase separation are reported, confirming the effectiveness of the technique. The electric force on a growing and rising bubble is then evaluated numerically in some simple cases, with a fem technique. Finally, original experiments on gas bubble detachment are analyzed in the attempt to enucleate the role of different mechanisms contributing to EHD enhancement. In particular, it is stressed that the role of electric forces in altering bubble shape and increasing bubble internal pressure seems to be the most significant in promoting bubble detachment.

‘Soup’ vs. ‘Sparks’: Alexander Forbes and the Synaptic Transmission Controversy

Summary During the twentieth century, a controversy raged over the role of electrical forces and chemical substances in synaptic transmission. Although the story of the ‘main’ participants is well documented, the story of ‘lesser’ known participants is seldom told. For example, Alexander Forbes, who was a prominent member of the axonologists, played an active role in the controversy and yet is seldom mentioned in standard accounts of the controversy. During the 1930s, Forbes incorporated chemical substances into his theory of synaptic transmission, advocating a complementarity model for the role of electrical forces and chemical substances. By focusing on Forbes and the axonologists, the controversy is simply more than a debate over ‘soup’ vs. ‘sparks’ but also involves the relative roles of electrical forces and chemical substances in synaptic transmission. The implications of this case study for the nature of scientific controversies are also discussed.

A Fluorometric Approach to Local Electric Field Measurements in a Voltage-Gated Ion Channel

Site-specific electrostatic measurements have been limited to soluble proteins purified for in vitro spectroscopic characterization or proteins of known structure; however, comparable measurements have not been made for functional membrane bound proteins. Here, using an electrochromic fluorophore, we describe a method to monitor localized electric field changes in a voltage-gated potassium channel. By coupling the novel probe Di-1-ANEPIA to cysteines in Shaker and tracking field-induced optical changes, in vivo electrostatic measurements were recorded with submillisecond resolution. This technique reports dynamic changes in the electric field during the gating process and elucidates the electric field profile within Shaker. The extension of this method to other membrane bound proteins, including transporters, will yield insight into the role of electrical forces on protein function.

On the role of electric forces in the processing of composites prepared with polymeric matrices

AbstractThermosetting and thermoplastic polymeric binders in the powder form and reinforcing carbon‐, glass‐, and organic fiber fillers were used to study the effects of electric forces on different stages of composites processing. Electric fields appear to uniformly distribute the powder binder across the filler surface as well as through its bulk. They favor stronger interaction of the components, leading to composites with better physical‐and‐mechanical performance properties. The optimal conditions provided for mixing of the components in an electrostatic field promote higher strength (by 1.5–1.8 times) and lower porosity (by 2–3 times) of carbon‐, and glass‐fiber reinforced plastics.

Comments on “The Role of Electric Forces in Charge Separation by Falling Precipitation in Thunderclouds”

Comments on “The Role of Electric Forces in Charge Separation by Falling Precipitation in Thunderclouds”

Comments on “The Role of Electrical Forces in Charge Separation by Falling Precipitation in Thunderclouds"

Comments on “The Role of Electrical Forces in Charge Separation by Falling Precipitation in Thunderclouds"

The Role of Electrical Forces in Charge Separation by Falling Precipitation in Thunderclouds

Abstract Theoretical expressions for the maximum electric field, the total and leakage currents, and the recovery time of the electric field have been developed for the failing precipitation mechanism of charge separation in thunderclouds. The derivations take into consideration the electrical forces acting on the precipitation and smaller particles. Quantitative dependence of the derived electrical parameters on the precipitation intensity and on the charge density of the precipitation particles has been studied in the case of the ice crystal-hailstone collision mechanism and the drop-splintering mechanism. Certain conditions for optimum efficiency of this charge separation process have been established and the minimum rates of precipitation required to generate different values of electric field have been calculated. It is inferred that precipitation particles of larger sizes will contribute more efficiently than the smaller ones in generating high electric fields. The results suggest lower and upper li...

The role of electric forces in the filtration of aerosols by fiber filters

The net electric charge on the fibers of various filters and the electric charge distributions of typical test aerosols were measured. A simple theory of filtration which included electric as well as mechanical effects was developed in order to apply these data to appropriate filtration results. Most fibers have an electric charge, even though it may be very small. When the test aerosol in filtration experiments is a homogeneous uncharged aerosol from a La Mer-Sinclair generator, a peak in the per cent penetration versus particle radius curves appears at approximately 0.05 μ, depending on the velocity of the air through the filter. The presence of electric forces of induction decreases the penetration of large particles and tends to decrease the radius at which maximum penetration occurs. When the aerosol used is a heterogeneous aerosol produced by any of the normal means, the peak in the penetration versus particle radius curves appears at larger values of the radius, depending upon the net electric charge per unit length of the fibers and the electric charge distribution of the test aerosol. It is pointed out that some unexplained filtration results may be due to some of the aerosol particles' escaping capture on contact. No attempt was made to assess the part played by electric forces in ensuring adhesion on contact.