Electrical probe ensures reliable contact in socket
Spring-loaded probe makes a reliable electrical contact by producing a circular wiping motion at the tip when inserted into a mating socket.
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The dynamic characteristics of a turbo-rotor simulator supported on gas-lubricated foil bearings. Part 2: Operation with heating and thermal gradients
A high speed rotor, supported by gas-lubricated foil bearings, is free from self-excited whirl and displays no loss of load capacity when vibrated at frequency equal to the rotational speed. It is demonstrated that in addition to tolerance of geometrical imperfections, misalignment and foreign particles, the foil bearing performs well at elevated temperatures and accommodates appreciable temperature gradients. The foil bearing is endowed with superior wipe-wear characteristics and the flexibility of the foil accounts not only for the stability of the foil bearing, but also for its accommodation of, and compensation for, distortion, contamination, and contact.
Licht, L.↗
Design, fabrication, and performance of foil journal bearing for the brayton rotating unit
Foil bearings were designed and manufactured to replace pivoted-shoe journal bearings in an existing Brayton Cycle turbo-alternator-compressor. The design of this unconventional rotor support was accomplished within the constraints and space limitations imposed by the present machine, and the substitution of foil bearings was effected without changes or modification other machine components. A housing and a test rig were constructed to incorporate the new foil-bearing support into a unified assemble with an air-driven rotor and the gimbal-mounted thrust bearing, seals, and shrouds of an actual Brayton Rotating Unit. The foil bearing required no external pressure source, and stable self-acting rotation was achieved at all speeds up to 43,200 rpm. Excellent wipe-wear characteristics of the foil bearing permitted well over 1000 start-stop cycles with no deterioriation of performance in the entire speed range.
Licht, L.↗
Waste Management System overview for future spacecraft.
Waste Management Systems (WMS) for post Apollo spacecraft will be significantly more sophisticated and earthlike in user procedures. Some of the features of the advanced WMS will be accommodation of both males and females, automatic operation, either tissue wipe or anal wash, measurement and sampling of urine, feces and vomitus for medical analysis, water recovery, and solids disposal. This paper presents an overview of the major problems of and approaches to waste management for future spacecraft. Some of the processes discussed are liquid/gas separation, the Dry-John, the Hydro-John, automated sampling, vapor compression distillation, vacuum distillation-catalytic oxidation, incineration, and the integration of the above into complete systems.
Ingelfinger, A. L.↗
Long-duration life tests of slip ring capsule assemblies for inertial guidance platforms
Eight slip ring capsules, each having 80 or 100 circuits, were operated for time periods ranging from 14,300 hours to 24,700 hours. The test mode simulated the motion of gimbal axes of the Saturn inertial guidance the platform in an organic free nitrogen environment. Computer-compiled noise data (approximately 45,000 recordings) were graphed as a function of test time and position within the capsules and as extreme probability distributions. Greater than ninety-nine percent of the noise measurements for the capsules with sufficient lubrication were less than 10 milliohms. Capsules with glass dielectrics did not perform significantly differently than those with filled epoxy dielectrics. The initial wear mode of prow formation was followed by rider wear. After 10 to the 8th power wipes, ring wear depth did not exceed the surface finish and the radial rider wear depth was less than 13 microns.
Cole, S. R.↗
Preliminary flight prototype waste collection subsystem
The zero gravity test program demonstrated the feasibility and practicability of collecting urine from both male and female crew members in a zero gravity environment in an earthlike manner not requiring any manual handling of urine containers. In addition, the testing demonstrated that a seat which is comfortable in both regimes of operation could be designed for use on the ground and in zero-gravity. Further, the tests showed that the vortex liquid/air separator is an effective liquid/air separation method in zero gravity. Visual observations indicate essentially zero liquid carry over. The system also demonstrated its ability to handle post elimination wipes without difficulty. The designs utilized in the WCS were verified as acceptable for usage in the space shuttle or other space vehicles.
Swider, J. E., Jr.↗
Gas-lubricated foil bearings for high speed turboalternator - Construction and performance
Foil bearings were designed and fabricated to replace pivoted-shoe journal bearings in a Brayton cycle turboalternator, within space limitations and constraints imposed by the existing machine. The foil bearings were integrated into a unified assembly with the rotor, housing, seals, and gimbal-mounted thrust bearing, without changes and modifications of machine components other than the journal bearings. The gas-lubricated foil bearings, which require no external pressure-source, furnished a stable support for a 21.9 pound rotor in the vertical attitude at speeds to 43,200 rpm. Excellent wipe-wear characteristics permitted well over 1000 start-stop cycles, without deterioration of performance in the entire speed range. The paper reviews salient aspects of design, fabrication, and performance. An account is given of rotor dynamics during starting, stopping, and traversing the region of resonances. The state of journal and foil surfaces is examined following intensive start-stop cycling and high-speed runs over extended periods of time.
Licht, L.↗
The Boltzmann- and the Klimontovich formalisms with reference to turbulence resolution
The Navier-Stokes equation expressed in terms of Klimontovich microscopic density is compared with the conventional one based on the Boltzmann formalism. Their difference is described by the two-point BBGKY equation. An implication is given that the averaging procedure from the Klimontovich to the Boltzmann formalism wipes out not only thermal agitation, but also a certain hydrodynamic turbulence. This is substantiated by agreement with measurements due to Schubauer and Klebanoff.
Tsuge, S.↗
Techniques of biological contamination avoidance by atmospheric probes
The likelihood of biologically contaminating a planet by an atmospheric probe has a low probability of occurring if the probe is kept biologically clean during terrestrial operations and if the structure remains in tact until the planets life zone is completely penetrated. High standards of cleanliness, monitoring and estimating for remedial actions must be maintained in a probe program. It is not a foregone conclusion, however, that heat sterilization needs to be employed. The use of several techniques having a good potential for lower probe costs are available and appear adequate to render a probe sterile within acceptable bounds. The techniques considered to be satisfactory for minimizing microbial load include: (1) combined heat (at 95-105 C) and gamma radiation; (2) short term heating at 105 + or - 5 C to inactivate all vegetative microbes; (3) irradiation routinely by ultraviolet light; (4) wiping by a bactericidal agent with or without a penetrant; and (5) cleanliness alone.
Defrees, R. E.↗
Rotating-vector TV cursor
Device is used as wiping signal to cover adjustable 360 degree arc of television raster. Device can also be used to generate television alinement reference to assist remotely-controlled payload operations.
Freedman, L. A.↗
Whence cometh /and goeth/ Jupiter's high energy electrons
Jupiter's decimetric emission is universally identified as synchrotron radiation from about 10 MeV electrons. These electrons radiate away their energy in a few months and hence must be continuously replaced. A theory in which electrons are injected at Jupiter's magnetopause and radially diffuse toward the planetary surface, gaining energy in the process is summarized. The radial diffusion coefficient in the inner magnetosphere is determined. This diffusion coefficient, which also holds for protons, is sufficiently small that the inner Galilean satellites can wipe out large fractions of the incoming proton and electron fluxes. The reduction of the proton flux is extremely important to the survival of the Pioneer experimental payloads.
Birmingham, T. J.↗
Effects of hydraulic fluid CVCM on silver-Teflon
Changes in the solar absorptance of silver-Teflon (Ag/FEP) surfaces were measured after contamination by the outgassing products of hydraulic fluid and irradiation by solar simulators. Although radiator surfaces are selected for stability to the solar ultraviolet and particulate environment, contaminant deposition and their interaction with solar exposure can degrade their performance. The test procedure to deposit the hydraulic fluid collected volatile condensible material (CVCM), irradiate, and determine solar absorptance changes by reflectance measurements using a spectrophotometer and a solar simulator is described. The tests showed that for the estimated deposition rates on the Ag/FEP, the hydraulic fluid CVCM fraction remaining under normal conditions (above -40 C) would not degrade its performance. The residual CVCM can be easily removed from Ag/FEP by wiping with a solvent saturated flannel. The changes in solar absorptance with the CVCM film thickness and the radiation exposure duration are reported, concluding that vacuum ultraviolet radiation did not prevent easy removal of CVCM.
Muscari, J. A.↗
Tribological properties of sputtered MoS sub 2 films in relation to film morphology
Thin sputter deposited MoS2 films in the 2000 to 6000 A thickness range have shown excellent lubricating properties, when sputtering parameters and substrate conditions are properly selected and precisely controlled. The lubricating properties of sputtered MoS2 films are strongly influenced by their crystalline-amorphous structure, morphology and composition. The coefficient of friction can range from 0.04 which is effective lubrication to 0.4 which reflects an absence of lubricating properties. Visual screening and slight wiping of the as-sputtered MoS2 film can identify the integrity of the film. An acceptable film displays a black-sooty surface appearance whereas an unacceptable film has a highly reflective, gray surface and the film is hard and brittle.
Spalvins, T.↗
Nonlinear interaction of two waves in boundary-layer flows
First-order nonlinear interactions of Tollmien-Schlichting waves of different frequencies and initial amplitudes in boundary-layer flows are analyzed using the method of multiple scales. Numerical results for flow past a flat plate show that the spatial detuning wipes out resonant interactions unless the initial amplitudes are very large. Thus, a wave having a moderate amplitude has little influence on its subharmonic although it has a strong influence on its second harmonic. Moreover, two waves having moderate amplitudes have a strong influence on their difference frequency. The results show that the difference frequency can be very unstable when generated by the nonlinear interaction, even though it may be stable when introduced by itself in the boundary layer.
Nayfeh, A. H.↗
Vacillation, sudden warmings and potential enstrophy balance in the stratosphere
The balance of potential enstrophy and its relationship to vacillation cycles and the sudden warming is studied for a beta-channel model of the stratosphere. It is shown that the mean flow cannot be steady in the presence of large-amplitude quasi-geostrophic waves (approximately 1-0.25 geopotential kilometers /gpkm/) when any dissipation is present, and the maximum wave amplitude allowed is approximately 2 gpkm. If wave forcing (transience plus dissipation) is artificially maintained, the mean flow decelerates slowly at first then explosively as the potential vorticity gradient of the basic state is wiped out over the channel. This process is called wave saturation. The initial phase of the explosive deceleration resembles both the observed and modeled mean flow evolution during a sudden stratospheric warming. A simple vacillation model based upon these ideas shows remarkable similarity to the results of Holton and Mass (1976) and Davies (1981).
Schoeberl, M. R.↗
Characteristic morphological and frictional changes in sputtered MoS/sub 2 films
Three microstructural growth stages of sputtered MoS2 films were identified with respect to film thickness: (1) ridge formation during nucleation, (2) an equiaxed transition zone, and (3) a columnar-fiber-like structure. Each of these growth stages are characterized in terms of microcrystallite size, shape, and orientation. The effective lubricating film thickness is established in terms of the microstructural growth stages during sliding experiments. The film has a tendency to break up within the columnar zone. Actual lubrication is performed by the remaining film which is 0.18 to 0.22 microns thick. Also a visual screening is proposed to evaluate the integrity of the as-sputtered MoS2 film. The lubricating properties are identified with respect to optical changes before and after wiping. The orientation of the microcrystallites are responsible for the optical reflective changes observed.
Spalvins, T.↗
On Why It Is Impossible to Prove that the BDX90 Dispatcher Implements a Time-sharing System
The Software Implemented Fault Tolerance SIFT system, is written in PASCAL except for about a page of machine code. The SIFT system implements a small time sharing system in which PASCAL programs for separate application tasks are executed according to a schedule with real time constraints. The PASCAL language has no provision for handling the notion of an interrupt such as the B930 clock interrupt. The PASCAL language also lacks the notion of running a PASCAL subroutine for a given amount of time, suspending it, saving away the suspension, and later activating the suspension. Machine code was used to overcome these inadequacies of PASCAL. Code which handles clock interrupts and suspends processes is called a dispatcher. The time sharing/virtual machine idea is completely destroyed by the reconfiguration task. After termination of the reconfiguration task, the tasks run by the dispatcher have no relation to those run before reconfiguration. It is impossible to view the dispatcher as a time-sharing system implementing virtual BDX930s running concurrently when one process can wipe out the others.
Boyer, R. S.↗
Tensile Fracture of Ductile Materials
For brittle materials, circular voids play an important role relative to fracture, intensifing both tensile and compressive stresses. A maximum intensified tensile stress failure criterion applies quite well to brittle materials. An attempt was made to explore the possibility of extending the approach to the tensile fracture of ductile materials. The three dimensional voids that exist in reality are modelled by circular holes in sheet metal. Mathematical relationships are sought between the shape and size of the hole, after the material is plastically deformed, and the amount of deformation induced. Then, the effect of hole shape, size and orientation on the mechanical properties is considered experimentally. The presence of the voids does not affect the ultimate tensile strength of the ductile materials because plastic flow wipes out the stress intensification caused by them. However, the shape and orientation of the defect is found to play an important role in affecting the strain at fracture.
Pai, D. M.↗