| Steady and Unsteady Flow in Straight Rectangular Ducts. |
APR 1975 |
|
| Authors:
V. O'Brien; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
 | A new solution for steady parallel flow in a rectangular duct is given that is valid for any aspect ratio a/b (where a and b are orthogonal half-widths of the duct), in contrast to older formulas that are restricted to certain ranges of a/b. New solutions for oscillatory flow in rectangular ducts are also given that replace a set of invalid published solutions. They provide calibration constants for relating local ... |
|
| Digital Simulation of a Synthetic Aperture Radar. |
MAR 1975 |
|
| Authors:
A. D. Goldfinger; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| To evaluate a synthetic aperture radar being designed for the SEASAT-A satellite a digital simulation was undertaken. A system operating in spotlight mode with step-chirp pulse compression was modeled. A bottleneck analysis of the software led to an economical implementation of this model. The ocean scattering model used assumed Rayleigh statistics. Ocean surface models representing chaotic seas and deterministic patterns, such at sea ice and oil slicks, were viewed by ... |
|
| Extending the Intercept Range of Tactical Missiles Against Jamming Targets. |
FEB 1975 |
|
| Authors:
J. E. Kain; D. J. Yost; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The main emphasis of this report is on the application of nonlinear filtering techniques to state estimation of radiating targets in range-denied systems. The mathematical model for the measurements and the target dynamics is derived, with emphasis on the development of a simplified model for the correlated errors introduced by the inertial reference unit. The nonlinear estimators considered (triangulation, extended Kalman filter, and Gaussian second-order filter) are evaluated using linearized ... |
|
| Structural Properties of Amorphous Semiconductors by Mossbauer Spectroscopy. |
31 DEC 1974 |
|
| Authors:
Norman A. Blum; Charles Feldman; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The Mossbauer effect in tellurium-125 was used to investigate the amorphous to crystalline transition in tellurium thin films. Techniques were developed for producing amorphous tellurium thin films and subsequently crystallizing them during the Mossbauer experiments. During the course of the work several Mossbauer tellurium sources were prepared and studied for narrow line high recoil-free fraction performance. Spectra of amorphous and crystalline tellurium films were compared in which the amorphous phase ... |
|
| Doppler Translocation Test Program. |
DEC 1974 |
|
| Authors:
Frederick M. Gloeckler Jr.; Richard R. Muniz; Glenn W. Schmeidel; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The report covers a program of test and evaluation of the AN/PRN-6 (XN-1) Doppler Backpack equipment for use in artillery surveying and, possibly, engineering survey work. Doppler data were obtained by the U.S. Army, U.S. Navy, and the U.S. Coast Guard simultaneously to determine the effectiveness of the various parameters in various modes of operation. The Doppler equipment uses the Navy Navigation Satellite System's radio transmissions of the satellite ephemeris ... |
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| The Data Editor/Doctor (The Second Generation Orbital Improvement Program), |
28 OCT 1974 |
|
| Authors:
B. J. Hook; H. D. Black; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A partial description of the data reduction computer program is given. |
|
| The Second Generation Integration Routine (IGC). MK5MD2 Version. |
21 OCT 1974 |
|
| Authors:
B. B. Holland; J. A. Yingling; M. A. Walko; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The enclosed pages represent revisions to TG 466 (Rev.) for the MK5MD2 version of the numerical integration routine used by the second generation orbit improvement program. |
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| Spacecraft Attitude Stabilization Systems. |
09 SEP 1974 |
|
| Authors:
L. I. Kargu; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| Various principles underlying the construction of spacecraft attitude stabilization systems are examined in this book. General data are presented on the angular motion and stabilization of spacecraft. The literature devoted to passive stabilization systems, reaction-wheel and control moment gyro stabilization systems, as well as to active stabilization systems using reaction jets is discussed. The book is intended for engineering technicians and scientists engaged in the design, calculation and study of ... |
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| A Guide to the TIP Computer. |
SEP 1974 |
|
| Authors:
H. K. Utterback; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The TIP (Transit Improvement Satellite) flight computer is a general purpose machine with specialized input/output logic to service the unique spacecraft functions. This report is a handbook for programming the TIP computer. A description of the registers is followed by a complete explanation of the instruction set. Use of the assembly program, ARTIC, is explained with some coding examples. Use of the computer simulator is also presented with instructions on ... |
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| Star Tracker/Mapper: System Design Parameters. |
SEP 1974 |
|
| Authors:
F. W. Schenkel; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| This document treats a variety of topics which must be considered by the designer of a star sensor system. The intent of the document is to consolidate these factors and relate their interdependence to provide an orderly design procedure. An attempt is made to relate the star sensor design to its specific application, whether satellite or earth-based. Among the topics discussed are general systems considerations, star characteristics, atmospheric effects, optics ... |
|
| Engineering Design of the Television Instrumentation System for the Harpoon Captive Flight Program. |
SEP 1974 |
|
| Authors:
J. J. Poetker; C. H. Ronnenburg; F. N. Sansone; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A Television Instrumentation System provides a data gathering and reduction system for use in the Harpoon Anti-Ship Missile Captive Flight Test Program being conducted at Pt. Mugu, California. The system is installed in an aircraft test bed that simulates the flight path of the Harpoon missile. The data are used to provide information concerning target acquisition, hit probability, miss distance, track noise, and ECCM performance. The system's electronic circuitry design ... |
|
| The Multirim Superflywheel. |
AUG 1974 |
|
| Authors:
D. W. Rabenhorst; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A new concept called the multirim superflywheel offers the prospect of combining many of the advantages of the circular brush superflywheel with the volume advantages of the solid disc flywheel. The result is a configuration enabling greater performance than any known flywheel concept in terms of system weight, volume, and cost. |
|
| Engine Development Program for the APL Remotely Piloted Vehicle. |
JUL 1974 |
|
| Authors:
T. R. Small; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| Performance of a custom-built (Sakert-Riggs) two-cylinder glow plug engine for use in the APL Remotely Piloted Vehicle was tested. Output power was less than expected, and plans to modify the engine to increase its power were foiled because of the early discovery of a structural weakness that showed up in every unit tested. An alternate engine was then developed, based on a low-cost proven design (McCulloch) that had been in ... |
|
| Bifilar Pendulum Technique for Determining Mass Properties of Discos Packages. |
JUL 1974 |
|
| Authors:
R. A. Mattey; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A bifilar pendulum was used to determine the mass properties of the Discos (Disturbance compensation systems) packages on the Triad satellite. The pendulum design was unique in that it allowed the package to be rotated into six different angular orientations. Each angular position was located with respect to the center of mass of the package. Analysis and results are given that show that the inertia matrix can be completed using ... |
|
| An Analysis of Two Problems Related to Over-the-Horizon Detection in the HF Band. |
JUL 1974 |
|
| Authors:
Edwin Shotland; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A 21 -dB discrepancy between theory and experiment concerning Bragg scattering of HF ground waves by a rough sea is analyzed and resolved. In addition, a new and more efficient method of non-dimensionalization is proposed for the quantities of radio propagation in the HF band that could be adopted by all electromagnetic and acoustical wave bands of propagation. It is especially useful in the application of the Norton-Barrick concept of ... |
|
| System Testing Techniques for Computer Networks, |
JUL 1974 |
|
| Authors:
R. G. King; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The trend in real-time systems is to use distributed processors operating asynchronously in networks. Testing a complex system of this nature becomes a major problem. System testing measures system performance to see if it needs prescribed standards. Testing is broken into three areas: hardware, processing logic, and data throughput. Methods of testing each area are described. These include input/output tests, memory tests, functional tests, system statistics, timing, stacks, and error ... |
|
| San Francisco Vessel Traffic System Test of the Traffic Analysis and Display Subsystem. |
JUN 1974 |
|
| Authors:
G. C. Gutheim; R. M. Hanes; D. G. Downer; J. R. Frock; R. C. Walters; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The report presents an experimental and analytical study of the traffic Analysis and Display subsystem (TAD) of the San Francisco Experimental Vessel Traffic System (VTS). The San Francisco Experimental VTS was designed to demonstrate the potential of a computer controlled automatic VTS that utilizes both radar sensors and voluntary movement reports from vessel in contiguous areas not served by radar coverage. Experimental studies were conducted to confirm performance parameters of ... |
|
| Lubrication-Space Experience and Design Criteria. |
JUN 1974 |
|
| Authors:
R. A. Mattey; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| Before a solid film lubricant warrants consideration for use on bearings and gears of space mechanisms, information relating to wear life and past applications is needed. This report presents a summary of information collected on the use of two solid film lubricants and a sputtered film of MoS2 on a number of space mechanisms. One film (inorganic) is composed of MoS2, graphite, gold, and sodium silicate and is referred to ... |
|
| Extendible Space Structures. |
JUN 1974 |
|
| Authors:
R. A. Mattey; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A list is given of all extendible and inflatable structures in space, along with the launching nation. Configurations of the coilable beryllium copper booms are illustrated, as well as associated engineering problems and solutions. Some unique extendible structures such as the Triad boom and coilable extendible structures are described. (Author) |
|
| Thermal Design and Analysis of the GEOS-C Spacecraft. |
MAY 1974 |
|
| Authors:
Harold G. Fox; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The thermal control of the GEOS-A and GEOS-B satellites designed and built by APL has been considered successful. Additional volume and structure were added to the basic GEOS-A/B reference in order to arrive at the GEOS-C configuration. The interior of the GEOS-C satellite consists of a more conductive heat transfer network and the spacecraft payload exceeds 700 pounds. In going to the GEOS-C configuration, it has been necessary to include ... |
|
| Path-Length Stability of the Ocean, Inferred from Ocean Temperature Measurements. |
MAY 1974 |
|
| Authors:
D. W. Stowe; F. C. Paddison; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| In an extensive ocean test at the Atlantic Undersea Test and Evaluation Center (AUTEC), fluctuations of acoustic path length were found to be no more than 0.001 meter rms for periods of 1 minute over a vertical path extending from an ocean depth of 60 to 320 meters. The measurements showed that the ocean is sufficiently stable to allow sophisticated coherent signal processing as would be necessary for synthetic aperture ... |
|
| Combustor Performance Parameters for Hydrocarbon Fuels. |
MAY 1974 |
|
| Authors:
F. S. Billig; P. J. Waltrup; L. A. Dale; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A survey of fuel producers and jet engine developers was made to determine the hydrogen carbon atom ratios and heats of formation of JP type fuels currently being used to estimate engine performance. On the basis of these results, standardized values were selected for JP-5, THMCPD (RJ-4), and Shelldyne H (RJ-5) for use in thermochemical computations. Calculations were made for the combustion of these fuels in a defined 'clean' air ... |
|
| An Annotated Bibliography on Walsh and Walsh Related Functions. |
MAY 1974 |
|
| Authors:
J. N. Bramhall; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The continuing rapid increase in the literature on Walsh functions during the year 1973 is reflected in the third edition of this bibliography. The entries in the bibliography are arranged in two formats: the primary citation and the three indices. In the primary citation the entire reference is given for each entry with (where possible) an abstract of the article. These citations are listed alphabetically by author and date. The ... |
|
| Probability of Crashing for a Terrain-Following Missile. |
APR 1974 |
|
| Authors:
Edward P. Cunningham; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The report deals with the derivation of a new expression for PC, the probability of crashing, for a terrain-following missile. It is compared with the older, commonly used expression for PC. In general, it gives more pessimistic results; i.e., the missile must fly higher in order to achieve a probability of not crashing equal to that obtained by the older method. (Author) |
|
| Use of Graphics in Software Design, Development, and Documentation. |
APR 1974 |
|
| Authors:
T. P. Sleight; A. Kossiakoff; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The emphasis in this work is on the use of graphics as medium for software design and development. The design of a computer system, the specification of system requirements, and the programming of computers all involve a mixture of personnel from different technical fields. Communication among such individuals instinctively involves diagrams or pictures of what is being discussed. In recognition of this point, computing systems should communicate with individuals by ... |
|
| Atmospheric Measurements Program. |
MAR 1974 |
|
| Authors:
J. R. Albertine; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The report describes a program of atmospheric turbulence and attenuation measurements conducted at the APL laser range. Attenuation was measured simultaneously at 0.63, 1.06, and 10.6 micrometers during a variety of fog conditions. Turbulence was monitored at 0.63 and 10.6 micrometers in order to provide insight into the amplitude and frequency spectrum of this atmospheric turbulence. (Author) |
|
| Precision Tracking. |
MAR 1974 |
|
| Authors:
Jeanette M. Rivoire; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The results of a precision (microradian) tracking study are reported. Several different filtering techniques were studied. The results indicated that the best of these techniques would reduce the rms error in angular measurement to 70% of the rms error caused by unfiltered measurement noise when the target exercised a 20-g, 1-Hz sinusoidal maneuver, and to about 50% of the error caused by unfiltered noise for a 1-g, 1-Hz target. (Author) ... |
|
| A Low Power RC-Coupled VHF Amplifier Designed for Fabrication by Hybrid Microcircuit Techniques. |
MAR 1974 |
|
| Authors:
G. R. Seylar; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A low power, high gain, VHF amplifier was designed for use in the RF amplifier chain of a tuned radio frequency receiver for satellite applications. The curcuit design was directed toward a topology and component use compatible with efficient fabrication as a hybrid microcircuit. Operating parameters were selected to optimize the relationship of using the least number of components while achieving the highest gain efficiency (ratio of RF gain to ... |
|
| Stability of the Acoustic Pathlength of the Ocean Deduced from the Medium Stability Experiment. |
JAN 1974 |
|
| Authors:
D. W. Stowe; L. H. Wallman; J. W. Follin Jr.; P. J. Luke; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| In an extensive ocean test known as the Medium Stability Experiment conducted at the Atlantic Undersea Test and Evaluation Center, rms linearly detrended fluctuations of acoustic pathlength were found to be of the order of lambda/100 at 10 kHz over a 1-minute period. Pathlength stability was deduced from precise measurements of acoustic travel time over a 2500-meter path extending from a 70-meter depth to the bottom of the ocean. A ... |
|
| The Motion of an Artificial Satellite in a Nonspherical Gravitational Field and an Atmosphere with a Quadratic Scale Height. |
JAN 1974 |
|
| Authors:
V. L. Pisacane; R. E. Willey; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The report presents the development of a solution for satellite orbits in a nonrotating atmosphere and takes into account the second through fourth zonal harmonics of the gravitational potential. It is basically an extension of Lane's work in that his power-law representation of the atmospheric density function, which implies a linear density scale height, is replaced by a density function with a quadratic density scale height. The quadratic scale height ... |
|
| Normal Mode Theory of Underwater Sound Propagation from Directional Multipole Sources, |
1974 |
|
| Authors:
Anton Haug; Ronald D. Graves; H. Ueberall; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| Normal mode theory of underwater sound propagation, which so far has been established only for omnidirectional point sources, is developed here for the case of sources with arbitrary spatial extent and directionality. This is accomplished by expanding the source in a series of spherical multipole distributions. From the Green's function representation, the sound field is then obtained for arbitrary multipolarity of the source, and it simplifies considerably for a point ... |
|
| Errors in the Ephemerides of Satellites Caused by Numerical Integration. |
DEC 1973 |
|
| Authors:
Ward L. Ebert; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The theory of the Jacobi Integral is presented in the context of a coordinate frame having a varying pole and rotation rate. Plots of this quantity are shown as obtained from the numerical integration of the equations of motion of an earth satellite, and comparisons of satellite ephemerides obtained by integration at different step sizes are given. Sources of error are isolated and recommendations are made concerning use of the ... |
|
| Software Architecture for the Traffic Analysis and Display System of the San Francisco Vessel Traffic System. |
DEC 1973 |
|
| Authors:
R. G. King; F. S. Gregorski; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The Traffic Analysis and Display (TAD) system for the San Francisco Experimental Vessel Traffic System (VTS) was designed to enable operators to obtain position, speed, and identification information on vessels of interest more accurately and quickly than was previously possible from manual systems. The basic system is described in other documents. However, a short description of the operator consoles is given here for clarity, followed by a description of the ... |
|
| Design Considerations for a 100-Megajoule/500-Megawatt Superflywheel. |
DEC 1973 |
|
| Authors:
David W. Rabenhorst; Robert J. Taylor; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The magnitude of stored energy required in high power bursts for modern experiments in physics has reached the point where capacitor banks previously used for this purpose are no longer practical. Although flywheels have been proven to be less expensive for this purpose and are one-hundredth the size, even the practicality of future flywheel-powered systems is being challenged by the magnitude of future experiment energy requirements. An existing steel flywheel ... |
|
| Structural Properties of Amorphous Semiconductors by Mossbauer Spectroscopy. |
30 NOV 1973 |
|
| Authors:
Norman Blum; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| Comparison of the 125Te Mossbauer spectra in amorphous and crystalline Te films indicates that in the amorphous phase the quadrupole splitting is about 20% greater and the recoil-free fraction about one-third as great as in the crystalline phase. The increase in quadrupole splitting is interpreted as indicating a decrease of about 3% in the length of the covalent bond between the nearest neighbor Te atoms in the amorphous state. The ... |
|
| Distortion Effects in Phase-Coded Radars with Digital Signal Processing. |
NOV 1973 |
|
| Authors:
A. D. Goldfinger; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The effects of single-bit digital signal processing upon the output of a phase-coded radar are considered. When a point target is viewed, the system response is approximately linear as long as the input signal-to-noise ratio is small compared to unity. The output signal-to-noise ratio is 2/pi times the value it would have for a truly linear analog system. When a target extending across R + 1 range bins is viewed, ... |
|
| Antenna Design Considerations for a Harbor Surveillance Radar. |
NOV 1973 |
34 pages |
| Authors:
A. J. Cote Jr; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
 | The report describes the examination of antenna design parameters performed during early development activity on the San Francisco Experimental Vessel Traffic System. This report outlines the basis for the initial choice of the antenna specifications; the final specifications varied slightly from those listed herein. (Author) |
|
| Automatic Detection and Tracking for the San Francisco Vessel Traffic System. |
NOV 1973 |
|
| Authors:
J. L. MacArthur; J. M. Davis; S. F. Oden; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The San Francisco Vessel Traffic System (VTS) was conceived as an automated complex that would free the system operators of all routine tasks, permitting them to concentrate on situations requiring human intervention. Accordingly, a radar detection system has been designed to automatically acquire and track all vessels within a defined surveillance region covering the San Francisco Bay and seaward approach to the Golden Gate. The report describes the two major ... |
|
| A Radar Altimeter for Satellite Application. |
OCT 1973 |
|
| Authors:
J. L. MacArthur; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A number of satellite radar altimeter designs have been proposed for the purpose of remotely sensing ocean surface parameters. A precision goal of 10 cm is commonly stated to fulfill the major desires of geodesy and oceanography. An altimeter design approach is discussed that requires only a few watts of peak transmit power, a particular advantage in satellite use. A burst programmed, phase-coded waveform is proposed with an effective compression ... |
|
| Sea Clutter Data Collection and Analysis for the Design of Harbor Surveillance Radar Systems. |
OCT 1973 |
|
| Authors:
JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The report presents a description of a sea clutter measurements program conducted at San Francisco during spring and summer of 1971 in support of the San Francisco Experimental Vessel Traffic System (VTS) development program. Using a mobile instrumentation van containing a high resolution radar and associated signal processing electronics, sea clutter characteristics of the entrance channel (from Point Bonita) and the inner harbor (from Treasure Island) were determined. (Author) |
|
| On Resolving Angle Ambiguities of n-Channel Interferometer Systems for Arbitrary Antenna Arrangements in a Plane. |
OCT 1973 |
159 pages |
| Authors:
James E. Hanson; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The concept of array ambiguity plot is introduced, and it is shown that there are exactly five distinct topological cases for antennas arranged in a plane. Some examples are given, including all regular polygon arrangements. The remainder of the paper is concentrated on those antenna arrays having a two-dimensional lattice point topology for their array ambiguity plots, as they appear to have the most forgiving tolerance requirements. Angle processing implementation ... |
|
| Computer Program Modularization. |
SEP 1973 |
|
| Authors:
Louis R. Gieszl; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The paper presents a five-step procedure for writing a complex computer program in such a way that the product is modular to the user as well as to the designer. This form of modularity is shown to be most needed in large-scale simulations; hence attention is restricted to this field. It is further assumed that the designer has already constructed some form of logical model (decision table, flow chart, list ... |
|
| Application of the Beam Diffusion Equation for Describing Light Intensity Fluctuations in a Randomly Inhomogeneous Medium. |
22 AUG 1973 |
|
| Authors:
N. V. Zubareva; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| It is shown that the beam cross-section remains constant when a light (electromagnetic) beam propagates through a medium having random inhomogeneities in its index of refraction, provided merely that certain mild statistical restrictions are required to be in force on the character of these vagaries in the medium, such as the need for uniformity and isotropy. (Author) |
|
| Triad Computer. |
AUG 1973 |
|
| Authors:
J. A. Perschy; B. M. Elder; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The Triad computer is a third-generation, general purpose, ground programmable digital computer used in the Triad satellite as a real-time controller operating under a priority interrupt system. It consists of a data processor, a memory section, and a power processor. The data processor uses standard and medium scale TTL integrated circuits on high density multilayer boards. The memory section, with a cycle time of 2.4 microsec consists of a 4K-word-by-16-bit ... |
|
| Flight Evaluation of the Disturbance Compensation System (DISCOS) Aboard the Triad Satellite. |
JUL 1973 |
|
| Authors:
A. Eisner; R. S. Yuhasz; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The Triad satellite contains an experimental control system called DISCOS (Disturbance Compensation System) which is designed to counteract the nongravitational forces operating on the satellite - notably those caused by atmospheric drag and solar radiation. Using information obtained from flight data from the pulse duration and frequency of the DISCOS thrusters, the performance of the system is compared with that expected in a modelled environment. A significant bias force is ... |
|
| Marching versus Nonmarching for a Periodic Incompressible Viscous Flow Problem. |
JUL 1973 |
|
| Authors:
L. W. Ehrlich; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| A fourth-order, time-dependent, partial-differential flow equation is solved by a coupled pair of finite-difference equations. Three marching techniques are compared with each other and with a nonmarching technique. (Author) |
|
| Solution of the Time-Dependent Navier-Stokes Equation with a Periodic Boundary Condition. |
JUL 1973 |
|
| Authors:
Louis W. Ehrlich; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The unsteady Navier-Stokes equation for two-dimensional viscous incompressible flow in a box is solved by a finite difference marching technique. The upper surfaces of the box are assumed to be in contact with a plate oscillating in time. Although the finite difference marching technique is not new, its application appears to be. (Author) |
|
| Structural Properties of Amorphous Semiconductors by Mossbauer Spectroscopy. |
31 MAY 1973 |
|
| Authors:
Norman Blum; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The amorphous to crystalline transition in vacuum deposited tellurium films has been observed using Mossbauer spectroscopy. Although the work is still preliminary, a large difference between the amorphous and crystalline forms of tellurium has been observed in the recoil free fraction as well as a smaller, but measurable, difference between the magnitudes of the quadrupole interactions. The samples studied contain 50% enriched tellurium-125 and are about 2 microns thick. Attempts ... |
|
| A System of Software for the TRIAD Flight Computer. |
MAY 1973 |
|
| Authors:
R. S. Yuhasz; H. K. Utterback; M. R. Newcomer; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The TRIAD satellite provided APL with its first opportunity to fly a general-purpose digital computer. The paper presents the system of software that was written to develop, test, and operate the APL-designed TRIAD computer. After a description of the machine's real-time flight requirements and its physical properties, the major software projects are discussed. These include the formulation of: Programming language, called ARTIC, and an associated assembler; special-purpose diagnostic and utility ... |
|
| Concentration and Temperature Studies of the R-Lines of Ruby. |
11 APR 1973 |
|
| Authors:
V. A. Gevorkyan; K. A. Malatyan; E. A. Kochinyan; V. Kh. Sarkisov; JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB
|
| The dependence of the duration and width of the R-lines of ruby luminescence on the concentration of chromium is studies. The dependence of the duration of luminescence lines on the length of the ruby crystal is also studied. With increasing chromium concentration in the ruby, the duration of the R-lines of luminescence decreases quickly at first, and then increases. When there is an increase of the chromium concentration, the width ... |
|
Reports by Corporate Author
