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Automatic phasing system periodically interrupts antenna operation for calibration intervals and measures phase and amplitude response at each active antenna element. Using these measurements, system adjusts phase shift and possibly gain of active elements during operating intervals to give desired antenna-gain pattern.
An approach to collisionless plasma shows the existence of current orthogonal to B along the low latitude boundary layer of the magnetosphere driven by electric field which is orthogonal to both B and the layer. In this case relationship P perpendicular + (sq B/8 pi) - (sq epsilon E perpendicular/8 pi) = constant holds on a line orthogonal to B and the layer, where epsilon is the dielectric constant of the plasma for electric fields orthogonal to B. Across the geomagnetic tail there flows a current in the direction of the dawn-dusk electric field, and in this case a relationship P perpendicular + (sq B/8 pi) + (sq epsilon E perpendicular/8 pi = constant, holds aong a line orthogonal to E and B. Divergence of both these currents is shown to be a source of Birkeland currents. Some of the boundary layer current is continuous with current across the tail. Electric currents of physically similar origin flow in interplanetary space, and when the magnetosphere interrupts them, additional Birkeland currents are driven.
A performance analysis of NASCOM Network circuits is presented. An objective of 99.80 percent availability has been established for all network circuits and an acceptable level of 99.50. A network narrative summary for the current month includes changes in network configurations, current month's totals for modes of service and trouble category losses, a discussion of trends, and significant losses that affected the performance indexes of individual or groups of circuits. A table and narrative summary of those circuits that failed to meet the objective of 99.80% availability for all network circuits and an acceptable level of 99.50. Lost time and interruption tables showing all circuits affected by outages, by trouble category, with their total time and events, scheduled operating hours, and individual availability indexes also are included. Selected circuits whose availabilities have or continue to affect the overall network availability are also analyzed.
The V-shaped potential structures formed by the injection of a non-neutral electron current into a cold background plasma were simulated numerically. The injection disturbs the initial quasi-neutral plasma, leading to the excitation of strong turbulences which heat the plasma. This leads to expulsion of the plasma from the simulation region. Due to ambipolar electric fields the current injection is interrupted and the initial background plasma is extracted from the system. A particle composition with the characteristics of the two plasma reservoirs now represents the plasma in the simulation region. The interaction of the electron beam with this plasma excites turbulences of smaller amplitudes. A nearly constant time averaged potential drop with nonstationary distribution develops across the system. Single and multiple double layers may form for the duration of one ion plasma period.
Hardware documentation is provided for the modified LORAN-C timing module, which uses interrupt-driven software control in determining loop sample times. Computer loading is reduced by eliminating polled operation of the timing loop.
Voyager 1 and 2 and Pioneer 11 data on the variations in the number density of low-energy plasma ions in the outer Saturn magnetosphere are discussed. Low and high latitude observations are compared in reference to the position of the spacecraft crossing of the field line. Abrupt decreases in the number density interrupted the tendancy for the number density to increase with spacecraft approach to Saturn. All three spacecraft are concluded to have encountered the same magnetospheric structure in the field line, with absorbers being present in the equatorial plane. The absorbers are suggested to be either gas or debris, which may be detectable visibly or with occultation techniques.
Inserts incorporated in support beams for silicon ingots automatically "dress" cutting blade during wafer slicing. Segments of blade-dressing material placed at regular intervals in graphite beam. Blade cuts into segments and dressed without operator intervention and without interrupting regular machine operation. Manual dressing eliminated, and production rates increased.
Tested ground-fault interruption circuit utilizing Hall-effect device to sense differential current in magnetic core tips and opens circuit.
Simple technique uses ordinary X-ray equipment. Weld line between hemispheres of hidden spherical pressure vessel examined for misalinement between hemispheres. Central X-ray tangent to pressure vessel at weld line. Technique not limited to spheres. Also used to check alinement between insulated sections of pipelines or chemical-reaction vessels without removing insulation or interrupting flow or process.
The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions.
Bone remodelling activity in the avian ulna was assessed under conditions of disuse alone, disuse with a superimposed continuous compressive load, and disuse interrupted by a short daily period of intermittent loading. The ulna preparation is made by two submetaphyseal osteotomies, the cut ends of the bone being covered with stainless steel caps which, together with the bone they enclosed, are pierced by pins emerging transcutaneously on the dorsal and ventral surfaces of the wing. The 110 mm long undisturbed section of the bone shaft can be protected from functional loading, loaded continuously in compression by joining the pins with springs, or loaded intermittently in compression by engaging the pins in an Instron machine. Similar loads (525 n) were used in both static and dynamic cases engendering similar peak strains at the bone's midshaft (-2000 x 10-6). The intermitent load was applied at a frequency of 1 Hz during a single 100 second period per day as a ramped square wave, with a rate of change of strain during the ramp of 0.01 per second.
Data on power, correlation time, and velocity were obtained at the Urbana radar using microcomputer and a single floppy disk drive. This system includes the following features: (1) measurement of the real and imaginary components of the received signal at 20 altitudes spaced by 1.5 km; (2) coherent integration of these components over a 1/8-s time period; (3) continuous real time display of the height profiles of the two coherently integrated components; (4) real time calculation of the 1 minute averages of the power and autocovariance function up to 6 lags; (5) output of these data to floppy disk once every 2 minutes; (6) display of the 1 minute power profiles while the data are stored to the disk; (7) visual prompting for the operator to change disks when required at the end of each hour of data; and (8) continuous audible indication of the status of the interrupt service routine. Accomplishments were enabled by two developments: the use of a new correlation algorithm and the use of the FORTH language to manage the various low level and high level procedures involved.
A number of key electrical safety requirements for the high voltage arrays of central station photovoltaic power systems are explored. The suitability of representative industrial DC power switchgear for control and fault protection was evaluated. Included were AC/DC circuit breakers, electromechanical contactors and relays, load interruptors, cold disconnect devices, sectionalizing switches, and high voltage DC fuses. As appropriate, steady state and transient characteristics were analyzed. Failure modes impacting upon operation and maintenance safety were also identified, as were the voltage withstand and current interruption levels.
A tracking system for measuring and recording the movements of a longwall shearer vehicle includes an optical tracking assembly carried at one end of a desired vehicle path and a retroreflector assembly carried by the vehicle. Continuous horizontal and vertical light beams are alternately transmitted by means of a rotating Dove prism to the reflector assembly. A vertically reciprocating reflector interrupts the continuous light beams and converts these to discrete horizontal and vertical light beam images transmitted at spaced intervals along the path. A second rotating Dove prism rotates the vertical images to convert them to a second series of horizontal images while the first mentioned horizontal images are left unrotated and horizontal. The images are recorded on a film.
A method is described for thinning an epitaxial layer of a wafer that is to be used in producing diodes having a specified breakdown voltage and which also facilitates the thinning process. Current is passed through the epitaxial layer, by connecting a current source between the substrate of the wafer and an electrolyte in which the wafer is immersed. When the wafer is initially immersed, the voltage across the wafer initially drops and then rises at a steep rate. When light is applied to the wafer the voltage drops, and when the light is interrupted the voltage rises again. These changes in voltage, each indicate the breakdown voltage of a Schottky diode that could be prepared from the wafer at that time. The epitaxial layer is thinned by continuing to apply current through the wafer while it is immersed and light is applied, to form an oxide film and when the oxide film is thick the wafer can then be cleaned of oxide and the testing and thinning continued. Uninterrupted thinning can be achieved by first forming an oxide film, and then using an electrolyte that dissolves the oxide about as fast as it is being formed, to limit the thickness of the oxide layer.
A simple one-dimensional cooling analysis is used to consider the cooling of a flow of pure sulfur on the Ionian surface by a combination of upward radiation and downward conduction, and some speculations on the nature of surface structures and optical properties for such a flow are made. It is concluded that surface folding caused by compressive stresses, crustal foundering due to tensile fracturing and density inversions, and local turbulence may result in regularly spaced surface ridges periodically interrupted by upwellings of liquid sulfur onto the frozen surface of the flow. The model suggests that although the color of the surface crust of a quickly quenched sulfur flow will not necessarily reflect the local internal temperature of the flow, diapiric upwellings and convection from beneath this crust should indicate the progressive cooling of the inner, more fluid zones of the flow.
The design of metal-vapor vacuum-arc switches (MVSs) for electromagnetic launchers is discussed, and preliminary results are presented for an experimental MVS. The general principles of triggered-vacuum-gap and vacuum-interrupter MVSs are reviewed, and the requirements of electromagnetic launchers are analyzed. High-current design problems such as electrode erosion, current sharing, magnetic effects, and thermal effects are examined. The experimental MVS employs stainless-steel flanges, a glass vacuum vessel, an adjustable electrode gap, autonomous internal magnetic-field coils, and a tungsten-pin trigger assembly. Some results from tests without magnetic augmentation are presented graphically.
Repeated surveys of short level lines in the Shumagin Islands, Alaska, reveal coherent tilt signals associated with subduction of the Pacific plate beneath the North American plate in the Shumagin seismic gap. Ten years of steady tilt down toward the trench is interrupted during 1978-1980 by a rapid episode of reverse tilt. The 'normal' tilt represents surface deformation as subduction occurs, with the plate boundary locked to at least 60 km depth. Using all available tilt, sea level, and seismic data, the tilt reversal is interpreted as due to an episodic reverse slip of about 80 cm magnitude on the plate boundary between about 70 km and 20 km depth, downdip from the main seismogenic zone, which remains locked. This event causes an increase of stress on the locked main thrust zone. It is speculated that such events may be a regular process at subduction zones, that great plate boundary earthquakes may be more common during their occurrence, and that their onset may be detectable early enough to give warning of an increase in probability for the occurrence of a great earthquake.