A theoretical and experimental investigation of cylindrical electrostatic probes at arbitrary incidence in flowing plasma

The theory for calculating the current collected by a negatively biased cylindrical electrostatic probe at an arbitrary angle of attack in a weakley ionized flowing plasma is presented. The theory was constructed by considering both random and directed motion simultaneous with dynamic coupling of the flow properties and of the electric field of the probe. This direct approach yielded a theory that is more general than static plasma theories modified to account for flow. Theoretical calculations are compared with experimental electrostatic probe data obtained in the free stream of an arc-heated hypersonic wind tunnel. The theoretical calculations are based on flow conditions and plasma electron densities measured by an independent microwave interferometer technique. In addition, the theory is compared with laboratory and satellite data previously published by other investigators. In each case the comparison gives good agreement

Analysis of a thioether lubricant by infrared Fourier microemission spectrophotometry

An infrared Fourier microemission spectrophotometer is used to obtain spectra (wavenumber range, 630 to 1230 0.1 cm) from microgram quantities of thioether lubricant samples deposited on aluminum foil. Infrared bands in the spectra are reproducible and could be identified as originating from aromatic species (1,3-disubstituted benzenes). Spectra from all samples (neat and formulated, used and unused) are very similar. Additives (an acid and a phosphinate) present in low concentration (0.10 percent) in the formulated fluid are not detected. This instrument appears to be a viable tool in helping to identify lubricant components separated by liquid chromatography

Laboratory calibration of AAFE radiometer/scatterometer (RADSCAT)

A brief description of the electrical and mechanical instrument configuration, followed by an extensive discussion of laboratory tests and results are contained herein. This information is required to provide parameters for data reduction, and a basis for analysis of the measurement errors in data taken with this instrument

Long Duration Exposure Facility (LDEF). Mission 1 Experiments

Spaceborne experiments using the space shuttle payload known as the Long Duration Exposure Facility are described. Experiments in the fields of materials, coatings, thermal systems, power and propulsion, electronic, and optics are discussed

Infrared emission spectrophotometric study of the changes produced by TiN coating of metal surfaces in an operating EHD contact

Infrared emission spectra and related measurements were obtained from an operating ball/plate elastohydrodynamic (EHD) sliding contact under a variety of operating conditions. In order to be able to compare the effect of the ball surface, some of the balls were coated with a thin layer of titanium nitride (TiN) by vapor deposition. Polyphenyl ether (5P4E) was used as lubricant and 1 percent of 1,1,2-trichloroethane (TCE) as a surface-probing additive. TiN is chemically inert and its thermal conductivity is lower than that of steel. Therefore, the overall temperatures with TiN coated balls were higher. Nevertheless, no scuffing was observed with the coated balls under conditions giving rise to scuffing with the uncoated balls. Tractions were lower with the TiN coated balls and always when TCE was added to the 5P4E. These findings were found to be inversely related to the degree of polarization of the spectral emission bands. The intensity and the dichrosim of these bands were related to shear rates and inlet conditions of the EHD contact

Characterization of lubricated bearing surfaces operated under high loads

The composition and surface profiles of M-50 steel surfaces were measured after operation at high loads in a bearing contact simulator. An ester lubricant (trimethyolpropane triheptanoate) was used with and without various additives. Optical profiles were obtained + or - to 30 depth resolution with a phase-locked interference microscope in 10 micron diameter areas within and outside the wear tracks. Optical constants and surface film thickness were measured in the same areas with an electronic scanning ellipsometer. Film composition was measured with a scanning Auger electron spectrometer. It is concluded that metal oxide formation is accelerated within the wear tracks

Surface profile changes of scuffed bearing surfaces

A phase locked interference microscope capable of resolving depth differences to 30 A and planar displacements of 6000 A was constructed for the examination of the profiles of bearing surfaces without physical contact. This instrument was used to determine surface chemical reactivity by applying a drop of dilute alcoholic hydrochloric acid and measuring the profile of the solid surface before and after application of this probe. Scuffed bearing surfaces reacted much faster than unscuffed ones, but bearing surfaces which had been previously exposed to lubricants containing an organic chloride reacted much more slowly. In a separate series of experiments, a number of stainless steel plates were heated in a nitrogen atmosphere to different temperatures and their reactivity examined later at room temperature. The change of surface contour as a result of the probe reaction followed an Arrhenius type relation with respect to heat treatment temperature. This result could have implications on the scuffing mechanism

Film thickness measurements on five fluid formulations by the mercury squeeze film capacitance technique

The thinning characteristics of five fluids were studied by measuring film thickness as a function of time. The mercury squeeze film capacitance technique was used. All tests were performed at room temperature. The synthetic hydrocarbon plus a nematic liquid crystal, N-(p-methoxybenzylidene)-p-butylaniline, thinned according to a Newtonian model and retained its bulk viscosity. The synthetic hydrocarbon plus a phosphonate antiwear additive and the synthetic hydrocarbon plus n-hexadecanol produced residual thick films. The synthetic hydrocarbon base fluids and the synthetic hydrocarbon plus a paraffinic resin displayed viscosity increases during thinning, but no residual films were formed

Earth resources-regional transfer activity contracts review

A regional transfer activity contracts review held by the Earth Resources Office was summarized. Contracts in the earth resources field primarily directed toward applications of satellite data and technology in solution of state and regional problems were reviewed. A summary of the progress of each contract was given in order to share experiences of researchers across a seven state region. The region included Missouri, Kentucky, Tennessee, Mississippi, Alabama, Georgia, and North Carolina. Research in several earth science disciplines included forestry, limnology, water resources, land use, geology, and mathematical modeling. The use of computers for establishment of information retrieval systems was also emphasized

Measurements of AAFE RADSCAT antenna characteristics

Antenna characteristics (active and passive) for a modified AAFE-RADSCAT parabolic dish antenna are documented for a variety of antenna configurations. The modified antenna was a replacement for the original unit which was damaged in January 1975. Pattern measurements made at Langley Research Center and Johnson Space Center are presented, with an analysis of the results. Antenna loss measurements are also presented and summarized