Stuart A. Hoenig

The mechanism of hemolysis by silica and its bearing on silicosis

Abstract A number of workers have linked the pathogenicity of silica with its capacity to damage biological membranes. We have investigated this membrane damaging process using red blood cells as a model membrane system. The following factors in the silica-membrane interaction were studied: concentration of reactants; rate of reaction; temperature dependence of the reaction; the effects of osmolarity, ionic strength, and pH on the reaction; factors terminating the reaction; the effect of the polymeric state of the silica; the effect of sialic acid removal from the membrane; the size-stability characteristics of the membrane defects; and the identity of the membrane component involved in the reaction. Our results suggest that silica hydrogen bonds to protein components of the membrane and subsequently abstracts these proteins from the membrane. These results appear to support the mechanism underlying the pathogenesis of silicosis advanced by A. C. Allison in 1971 with the exception that our experimental findings favor a silica-protein interaction rather than the silica-lipid interaction proposed by Allison.

Chemisorption of oxygen on zinc oxide, effect of a dc electric field☆

Abstract The effect of external electric fields on chemisorption of oxygen on zinc oxide was measured. The chemisorption takes place by an electron transfer mechanism and desorption is due to hole migration to the ZnO surface. The adsorption-desorption process may be controlled by the application of external electric fields.

New Applications of Electrostatic Technology to Control of Dust, Fumes, Smokes, and Aerosols

New applications of electrostatics to the control of dust are investigated. Technology for pushing systems to keep dust off optical systems and move particulates out of airstreams are discussed. Other electrostatic techniques for removal of water droplets and smoke are investigated.

Exo-electron emission during heterogeneous catalysis (the effect of external electric potentials)

Abstract Exo-electron emission was observed during catalytic oxidation of CO, H 2 or NH 3 on hot platinum. The exo-electron current level was related to the rate of reaction. Suppressing or enhancing the exo-electron current decreased or increased the rate of reaction.

Observations of exoelectron emission associated with heterogeneous catalysis

It is suggested that the exoelectron emission from the catalyst may be used to monitor the rate of oxidation of CO and CH4 over palladium catalysts. Indirect heating of the catalyst and atmospheric pressure have no effect upon this monitoring system. Although the mechanism relating catalysis to exoelectron emission is not clear, it is considered possible that electron emission is triggered by the adsorption-desorption cycle.

Fine Particles on Semiconductor Surfaces: Sources, Removal and Impact on the Semiconductor Industry

The impact of fine particles and organic contamination on device yield is very serious. We have investigated several technologies in this area. They include: 1) Application of thermophoresis for the prevention of surface contamination. 2) The use of electrets for collection of particles that might otherwise settle on surfaces. 3) The use of dry ice snow as a cleaning medium for the removal of particulates and organic contamination.

EMISSION OF HIGH‐ENERGY ELECTRONS DURING ALLOY‐EVAPORATION PROCESSES ON HOT METAL FILAMENTS

Hot metal filaments are often used to evaporate another metal for deposition of thin films. If the metal being evaporated can alloy with the filament, a significant number of high‐energy electrons are emitted during the alloying‐evaporation process.

Application of electrochemical technology to the improvement of rock-drilling systems

Abstract Studies of rock drilling with water-based mud have indicated the existence of a current of electrons from the rock to the drill. If this so-called “normal current” is reduced to zero or is reversed by an applied potential, there is a significant reduction in drill wear. The wear rate is enhanced if oxygen is bubbled through the drilling mud and reduced if nitrogen is used, but in any case the electrical effects can still be observed. Observation of the normal drilling current with an oscilloscope has suggested that, when the drill is “sharp”, the normal current is a time-varying d.c. signal with most of the signal levels at frequencies below 25 Hz. As the drill becomes dull, the number of higher frequency signals and the overall signal amplitude increase. We suggest that this change in signal frequency with wear can be used to monitor the condition of an operational drill.

Electrostatic techniques for protection of optical components in dusty environments

Electrostatic techniques can be used to keep dust and aerosols from depositing on optical components. The system makes use of a corona discharge and a safety screen, located out of the optical path, to charge the incoming dust and then push it away from the optical surface. The system is effective for the dust particles normally found in the atmosphere, power consumption is quite limited.

Generation of Pernanent, Dry, Electrical Contacts by Tattooing Carbon into Skin Tissue

The introduction of sterile collodial carbon into the dermis produces an area of low electrical resistance in the intact skin. The low resistance spot is suitable for long term, dry contact, stimulation or specialized ECG/EEG measurements.