Charge Elimination Research Articles

DC component appearing in the corona current of a point-to-plane electrode system capacitively coupled to an ac voltage source

In a point-to-plane electrode system capacitively coupled to an ac voltage source, a dc component is produced in the ac corona current flowing through the gap when the insulation of the high voltage electrode of the gap is deteriorated. As a result, a quantitative difference in positive and negative ions is produced in the gap and this causes overcompensation in the charge elimination. For a multiple-point electrode system, also, a dc component will be produced if there is an irregular gap in a row of point electrodes. In order to attain complete charge elimination by using these systems, precautions should be taken regarding these matters.

The role of electrostatic interactions in the mechanism of peptide bond hydrolysis by a Ser-Lys catalytic dyad.

General-base catalysis in the active site of serine proteases is carried out by the imidazole side chain of a histidine. During formation of the transition state, an adjacent carboxylic acid group stabilizes the positive charge that forms on the general-base catalyst and as a result contributes several orders of magnitude to the catalytic efficiency of these enzymes. In the recently discovered family of self-cleaving proteins exemplified by the LexA repressor of Escherichia coli, instead of the imidazole of a histidine, the active-site general-base catalyst was found to be the epsilon-amino of a lysine. The considerably higher capacity of the lysine side chain for proton acceptance raises interesting questions concerning the role of electrostatic interactions in the mechanism of proton transfer by this highly basic group. The negative charge elimination studies described here and their effects on the kmax and pK of LexA self-cleavage are consistent with a model in which electrostatic interactions between an acidic side chain and the general-base catalyst form a barrier to proton transfer. The implications are that the epsilon-amino group, unlike the imidazole group, is capable of effecting proton transfer without the intervention of a countercharge.

Static Charge Elimination of Charged Matter Using UV Lamp

Static charge elimination of a charged matter can be achieved using a low pressure quartz mercury lamp. Positive charge elimination is by photoelectrons emitted from the quartz surface of the lamp and negative charge elimination by photoelectrons emitted from the charged matter. This technique can be used in the case where inflammable gases are present and be used even under vacuum conditions.

Static Charge Elimination of Charged Matter by Vacuum UV Irradiation

Air is photoionized by the irradiation of vacuum UV light emitted from a deuterium lamp with a MgF2 window. The short wavelength transmission limit of this lamp is 112 nm, which corresponds to the photon energy of 11 eV, and nitric oxide is firstly produced by photochemical reaction and photoionized by those photons having an energy of 11 eV. The lamp behaves like a radio isotope, and its irradiation accelerates the charge elimination of charged matter in air.

Photoelectron Emission from the Quartz Surface of an Ultraviolet Lamp under Atmospheric Conditions

Photoelectrons are emitted from the quartz surface of an ultraviolet lamp under atmospheric air conditions, and the lamp behaves like an electron emitter. The lamp used in the present experiment is 4 W and has light emission peaks at 185 nm and 254 nm. With this lamp, the emission current of the order of 10-9 A is produced in atmospheric air. This photoemission phenomenon is of great importance to charge elimination of charged matter.

The role of water vapor in the charge elimination process for flowing powders

Effective charge elimination of flowing powders in a solid-gas multiphase system by addition of charge-neutralizing carriers, such as ammonia (gas), water droplets (liquid), and activated charcoal fines (solid) have been reported. The charge neutralization process, however, is still not clearly known at present. This paper proposes a general mechanisms of charge elimination based on hydrated ion clusters (H 2O) n H + and (H 2O) n OH −, and their polymers. Measurements of electrostatic charges of flowing glass beads in a continuous copper pipe loop with air carrier containing oxygen, nitrogen, or ammonia using an upgraded Faraday probe measuring system were made with water vapor contents ranging from 0% relative humidity (R.H.) up to 80% R.H. The agglomerate hydrated ion clusters are believed to act as the major charge carriers to neutralize charges on the particle surfaces or to redistribute them into the surrounding space. In the absence of water vapor, the charge elimination techniques tested in our experiments were found not to function properly. The effectiveness of the charge elimination process is strongly affected by the population of the clustered aggregates.

The Ventricular Intracardiac Unipolar Paced‐Evoked Potential in an Isolated Animal Heart

The endocardial unipolar paced evoked response has excited a great deal of interest due to its possible use in the measurement of the metabolic state of the body and other pacer-related areas. Although rate-responsive pacing utilizing this signal has been clinically evaluated, little is known regarding the behavior of the components of this waveform under normal physiological conditions. We have developed an electronic circuit which allows the recording of the evoked response within a few milliseconds of a pacing stimulus of 5 V and 0.5 ms duration being applied using a single unipolar, smooth platinum electrode of 14 mm2 surface area. The paced evoked response was measured using a total of 20 isolated rabbit heart preparations. Five were run for 8 hours and the remaining fifteen were run for 5 hours. Our results indicate that the waveform components of the evoked response remain stable while the preparation is viable, but that two of the time-related measurements change with loss of viability. A significant lengthening of the stimulus-R interval was seen together with a dramatic shortening of the R-T period. The net result of these changes was an overall reduction of 17% in the complex duration. In addition, we found the R-T shortening to be a sensitive measure of myocardial integrity. We conclude that the combination of our interface charge elimination circuit and the isolated heart preparation has proved a useful system for the investigation of the paced evoked potential. Furthermore, the loss of myocardial viability has a complex action on this response.

MEASUREMENT AND CONTROL OF ELECTROSTATIC CHARGES ON PULVERIZED COAL IN A PNEUMATIC PIPELINE∗

Abstract Pulverized coal particles flowing in a pneumatic pipeline are naturally charged to a detectable level due to collisions with pipe walls. Systematic charge measurements of Anthracite (AN) coals, Medium Volatile Bituminous (MVB) coals and Lignite A (LIGA) coals in a grounded copper pipe have been made with an upgraded charge measuring system. The net particle charges were found to be positive, although both negative and positive charges were detected in all experiments. Effects of air humidity and conveying velocity on particle charges were examined. The mean particle charge was found in the order of 10−12 Coulomb and the charge-to-mass ratio in the order of 10−5 C/kg. Charge elimination techniques by strict humidity control and by introducing neutralizing charge carriers, such as minus 1 μm activated charcoal fines, ammonia, and piezoelectric ionized gas were explored. Effective reduction of 70 % to 85 % of particle charges was achieved. A charge neutralization mechanism was proposed to interpreta...

Charge Elimination in Pneumatic Conveyor Line of High-Resistivity Powders

A pipe-shaped static charge eliminator with high performance and safety has been developed for use in pneumatic conveyor lines. It consists of grounded corona electrodes attached on the inner surface of a glass cylinder, and an exciting electrode covering its outer surface and molded in resin insulator. The electrode system is encapsulated in a metal casing and connected to a pneumatic conveyer line. A high-frequency exciting voltage with 2 kHz and 2.5-kV peak voltage is applied between the corona electrodes and exciting electrode to produce surface discharge as a plasma ion source over the inner surface of the glass cylinder which prevents dangerous sparks from occurring. Assuming the ionic current density from the plasma ion source for eliminating the space charge of the powder cloud to be proportional to the local intensity of the space-charge field at the ion source and the average flow velocity of the powder cloud, a theoretical formula of charge elimination is derived. Then charge elimination tests are carried out using four different kinds of powders. The results obtained confirm the validity of this formula. The present charge eliminator can reduce the powder charge down to five percent of its initial value with only 90 cm length in the gas flow direction at 30-40?m particle size and less than 100-g/m3 mass-loading.

Production and release of ions in the Fast Atom Bombardment ion source

FAB spectra have been obtained from several organic diammonium salts. The free dication was observed in only one case. Solid samples of the salts did not yield simply interpretable data. Mass spectra of the salts from a glycerol or glycerol/inorganic salt matrix exhibit several cation and anion related peaks as well as numerous singly charged fragment ions corresponding to charge separation, dealkylation, and elimination reactions accompanied by hydrogen transfer. These results point to low energy desorption pathways of preformed ions from immobile solid phases and mobile, concentrated liquid or high pressure gas phases.

A simple method for elimination of charging, and for current integration in PIXE analysis of thick insulating samples

A simple method has been developed for the elimination of charging, and for accurate beam current/charge measurement, when thick insulating samples are being analysed by PIXE. This technique involves simply placing a thin foil of a suitable material, (e.g. C, Al, Ni, Au, Au, on C, etc.), 1–2 cm in front of the target, and monitoring the backscattered particles from it with a surface barrier detector. The incident beam of charged particles produces a sufficient number of electrons in the forward direction, from this foil, to neutralize the positive charge accumulating on the thick insulating target. At the same time the backscattered particles from this foil, as monitored by the detector which is completely shielded from the target, give an accurate measure of the incident current/charge. The effectiveness of this method of charge elimination has not only been demonstrated by vast improvement in the PIXE spectra, but also by the resonance shift method in the yield curves of the 19F(p, αγ) 16O reaction from a thick insulating CaF 2 target. It is suggested that this foil technique would be equally well suited to other ion-beam analysis work.

Relation between enzymic catalysis and energy coupling.

The principles that underlie enzyme catalysis also apply to energy coupling processes. A comparison is made between a kinase system that mediates the phosphorylation of glucose by ATP (hexokinase), as the prototype for enzymic catalysis, and the mitochondrial electron-transfer complexes, as the prototypes for energy coupling systems. Induced polarization of chemical bonds and charge separation and elimination are common component events of both enzyme catalysis and energy coupling. Thus, definite limits can be imposed on models of energy coupling; they must comply with the basic principles of enzymic catalysis.

The charge decay kinetics in irradiated rubber after exposure to light

The kinetics of the decay of charged particles trapped in a butadiene-acrylonitrile (BDAN) copolymer, with or without electron donor or acceptor additives, and irradiated at 77°K, were studied. The kinetics of charge decay on exposure to light of decreasing wavelength are “stepwise” in nature. The charge recombinations produced by light of λ ⩾ 700 nm in rubber with or without addition of phenyl-β-naphthylamine proceed in two stages (a rapid and a slow one), while there is only a single stage in rubbers with addition of chloranil. The charge recombination kinetics can be formally described by a reaction of first order in both the stages. The rate constant of the charge decay drops in the presence of an electron donor or acceptor, and on increasing the γ-radiation dose. The formation of radicals competes with that of molecular products during the photo-recombination of the charges. The efficiency of charge elimination depends on the visible light intensity, i.e. raising the latter will result in an additional decrease in the concentration of paramagnetic centres.