| CHARACTERISTICS OF 3-5 MICRONS SCINTILLATION AT LOW ALTITUDES IN A COASTAL MARINE ENVIRONMENT, |
APR 1996 |
|
| Authors:
T. L. KLEIN; J. P. REILLY; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
 | (U) THIS PAPER PRESENTS OBSERVATIONS AND COMPARISONS WITH THEORY OF INFRARED TARGET SCINTILLATION IN THE 3-5 MICRON BAND. THE OBSERVATIONS DESCRIBED WERE MADE FROM THE MARYLAND COAST IN MAY 1955 WITH DUAL SYNCHRONIZED CAMERAS AT HEIGHTS OF 20 AND 27 M, RANGES FROM 4 TO 32 KM, RECEIVER APERTURES FROM 2.5-11.5 CM, TARGET AREAS FROM 250-2000 CM2, FRAME RATES FROM 0.5-217 HZ, AND A VARIETY OF METEOROLOGICAL CONDITIONS. TURBULENCE PARAMETERS ... |
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| INCORPORATION OF SCINTILLATION IN INFRARED DETECTION AND TRACK MODELS FOR LOW ALTITUDE TARGETS IN A MARINE ENVIRONMENT, |
APR 1996 |
|
| Authors:
D. L. MARABLE; F. R. CASTELLA; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| (U) THIS PAPER PRESENTS A METHOD FOR INCORPORATING THE EFFECTS OF TARGET SIGNAL SCINTILLATION DUE TO ATMOSPHERIC TURBULENCE INTO INFRARED DETECTION AND TRACK PERFORMANCE MODELS. USING THE THEORETICAL DESCRIPTIONS OF SCINTILLATION , AN ANALYTICAL MODEL FOR PRODUCING THE PROBABILITY OF DETECTION CURVES FOR AN INFRARED SENSOR IS DEVELOPED. LIMITATIONS OF THE MODEL CAUSED BY THE LOG NORMAL DISTRIBUTION ASSOCIATED WITH SCINTILLATION ARE DISCUSSED. VARIOUS INFLUENCES ON SYSTEM DESIGN ARE DISCUSSED ... |
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| Magnetospheric Morphology and Dynamics: Specification of the Near-Earth Operational Environment |
03 JAN 96 |
21 pages |
| Authors:
Ching-I. Meng; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
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| Two-Centimeter GPS Measurement System for Missile Intercept T&E |
96 |
11 pages |
| Authors:
T. Thompson; L. J. Levy; J. M. Dougherty; T. M. Hattox; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
 | Accurate scoring (miss or impact measurement) of missile intercept tests is required to adequately assess lethality. Instrumentation approaches based on a suite of sensors (e.g., Doppler radar Miss Distance Indicator, optical fiber Photonic Hit Indicator, and ground radar tracking) are not capable of meeting the full range of requirements. On the other hand, our long experience with Trident missile system accuracy evaluation and early BMD intercept testing suggests that dual ... |
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| Development of a Towed Underwater Launch Platform |
96 |
10 pages |
| Authors:
K. N. Parthasarathy; B. E. McGrath; D. A. Frostbutter; J. J. Wozniak; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The concept of a new test facility to evaluate the underwater launch and flight performance of full-scale missiles and associated launcher systems is described. Results from preliminary studies on estimates of the platform dimensions hydrodynamic characteristics, and platform response to a missile launch impulse are included. The VSAERO panel method code was used to generate hydrodynamic force and moment coefficients for the condition of steady tow at 5 knots. These ... |
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| Incorporation of Non-Destructive Centrifuge Tests into Missile Guidance Assessment |
96 |
26 pages |
| Authors:
Dean A. Payne; Harvey Feltquate; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| As an adjunct to the Navy's surveillance program for guidance assessment, the FBM Guidance Branch is considering a test program in which operational Trident II guidance system fleet assets would be flown on a centrifuge. This paper outlines an approach to the analysis of the guidance data. A test for tactical representativeness is described, as well as an approach to the optimal combination of centrifuge data with test flight data, ... |
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| Proceedings of the Systems Reengineering Technology Workshop (4th) held in Monterey, California on February 8 - 10, 1994 |
SEP 94 |
412 pages |
| Authors:
Bruce I. Blum; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The Navy has invested significant resources in the development of large and complex systems that must be modified and extended to respond to changing requirements. However, many of these systems are based on archaic automation technologies that do not support modern hardware and software engineering methodologies or maintenance strategies. Consequently, system modification has become increasingly complex. To reduce the complexity, developers can employ reengineering techniques to create new systems. This ... |
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| An Automated Naval Oceanographic Monitoring System |
JAN 94 |
6 pages |
| Authors:
John C. Neal; H. L. Dantzler Jr.; David J. Sides; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An automated prototype oceanographic monitoring system has been developed |
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| A Practical Probabilistic Analysis Method for Hydrocode-Based Lethality Assessment |
1994 |
12 pages |
| Authors:
James L. Lamb; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| A new approach for practical hydrocode based lethality assessment is proposed. The approach couples hydrocode impact analysis with more efficient probabilistic analysis methods originally developed by the structural reliability community. The probabilistic methods are based upon advanced reliability methods which utilize reasonable assumptions together with efficient iteration and convergence algorithms to obtain an approximation of the boundary in engagement space that separates those intercepts ... |
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| Optical Properties of Diamond. |
1994 |
|
| Authors:
Michael E. Thomas; William J. Tropf; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Because of its excellent thermal-mechanical properties, diamond is a promising infrared window material. With the development of chemical vapor deposition (CVD) diamond technology, diamond windows and domes are becoming a practical reality. The infrared transmittance of type IIa and CVD diamond was characterized as a function of temperature, and the room-temperature ultraviolet transmittance of type IIa diamond was also measured. These experimental results were interpreted in terms of intrinsic and ... |
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| Modeling of Pulsed-Laser Cleaning of Metal Optical Surfaces at Cryogenic Temperatures. |
1994 |
|
| Authors:
A. N. Jette; R. C. Benson; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Pulsed-laser cleaning of metal optical surfaces at cryogenic temperatures is modeled. Temperature dependencies of the substrate thermal and optical parameters were taken into account since they are quite sensitive to thermal variations at very low temperatures. Calculations of the heating of clean substrates were done to determine damage thresholds as well as computations of the heating of absorbing and transparent films on the substrates to ascertain the film removal process. ... |
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| Time Maintenance System for the BMDO MSX Spacecraft, |
02 DEC 1993 |
|
| Authors:
Martin J. Hermes; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The Johns Hopkins University Applied Physics Laboratory (APL) is responsible for designing and implementing a clock maintenance system for the Ballistic Missile Defense Organizations (BMDO) Midcourse Space Experiment (MSX) spacecraft. The MSX spacecraft has an on-board clock that will be used to control execution of time-dependent commands and to timetag all science and housekeeping data received from the spacecraft. MSX mission objectives have dictated that this spacecraft time, UTC(MSX), maintain ... |
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| Ground Control System for the Midcourse Space Experiment UTC Clock, |
02 DEC 1993 |
|
| Authors:
Richard Dragonette; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| One goat of the Midcourse Space Experiment (MSX) spacecraft Operations Planning Center is to maintain the onboard satellite UTC clock UTC(MSX) to within 1 millisecond of UTC(APL) (the program requirement is 10 msec). The UTC(MSX) clock employs as its timebase an APL built 5 MHz quartz oscillator, which is expected to have frequency instabilities (aging rate + drift rate + frequency off-set) that will cause the clock to drift approximately ... |
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| High Peak Power Microwaves: A Health Hazard |
01 DEC 93 |
101 pages |
| Authors:
Henry A. Kues; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Prior research has established the ability of microwave exposure to produce a variety of biological effects including ocular changes. Investigations in our laboratory have demonstrated corneal endothelial lesions, increased vascular permeability, electroretinographic changes and structural damage. The present study was designed to verify previous results using high-peak-power pulsed microwave exposure (1.25 GHz, 1MW peak power, 1 or 16 Hz, and pulse duration of 0.5 or 10 microns) and to determine ... |
|
| Single-Event Upset Testing of the Performance Semiconductor 1750A CMOS/ SOS Chip Set |
30 SEP 93 |
16 pages |
| Authors:
James D. Kinnison; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Complex computer systems in space are vulnerable to many different environmental effects. One of the most difficult problems is survival under exposure to charged-particle radiation. Microelectronic devices are particularly sensitive to single-event upset-a change in the logic state of a dynamic node or memory cell due to interaction with cosmic rays. For reliable computing in satellite systems, designers must understand the sensitivity of the computer components to single-event upset. A ... |
|
| Origins of Solar Activity - First Year Report, AASERT Grant |
01 AUG 93 |
3 pages |
| Authors:
David M. Rust; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| This report describes the first year of training and progress of Mr. J.J. Blanchette toward a Ph.D. in Physics, with specialization in Solar Physics. Mr. Blanchette has met all academic requirements to proceed with thesis research. He is a full-time graduate research fellow, and he has gained a good background in solar activity research. He has taken on the task of implementing the focal-plane functions of the Target Selector Telescope ... |
|
| Ship Self-Defense Against Air Threats. |
JUN 1993 |
|
| Authors:
D. R. Ousborne; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Solar Vector Magnetic Field Research |
31 MAR 93 |
|
| Authors:
David M. Rust; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The objective of the project was to measure the magnetic fields in solar active regions, develop methods for predicting solar flares on the basis of the measurements, and improve the instrumentation for solar magnetic field measurements. In cooperation with the staff at the Solar Branch of the USAF phillips Laboratory, field measurements were made almost daily during the grant period. The principal result of analyses carried out so far is ... |
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| An Investigation of the Near Earth Space Environments |
JAN 93 |
12 pages |
| Authors:
Ching I. Meng; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Progress has been made in four areas: (1) Mapping the different regions of the magnetosphere into the ionosphere under varying solar wind conditions. This research is relevant to future USAF operational systems needs in that the environment experienced by a spacecraft differs greatly depending on the region being transited. (2) Understanding the convection surge mechanism in the magnetotail. (3) Determining the plasma source region for dayside auroral emissions through coordinated ... |
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| The Kinematic Equation for the Rotation Vector. |
JAN 1993 |
|
| Authors:
M. D. Shuster; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Different derivations of the kinematic equation for the rotation vector are discussed within a common framework. Simpler and more direct derivations of this kinematic equation are presented than are found in the literature. The kinematic equation is presented in terms of both the body-referenced angular velocity and the inertially referenced angular velocity. The kinematic equation is shown to have the same form in both the passive and active description of ... |
|
| Optical Properties of Diamond. |
JAN 1993 |
|
| Authors:
M. E. Thomas; W. J. Tropf; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| High-Temperature Superconducting Electromagnetic Radiation Detectors. |
JAN 1993 |
|
| Authors:
R. M. Sova; B. E. GRABOW; B. G. BOONE; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Oxidation of Hafnium Carbide in the Temperature Range 1400 to 2060 Degrees C |
93 |
|
| Authors:
C. Brent Bargeron; Richard C. Benson; A. Norman Jette; Terry E. Phillips; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Although hafnium carbide has been oxidized at temperatures in the range of 1400 to 2060 C, three distinct layers are present in the film cross section:(a) a residual carbide layer with dissolved oxygen in the lattice, (b) a dense appearing oxide interlayer containing carbon, and (c) a porous outer layer of hafnium oxide. Experimental measurements of layer thickness and oxygen concentrations are combined with an extended formulation of moving boundary ... |
|
| Vacuum-Ultraviolet Characterization of Sapphire, ALON, and Spinel Near the Band Gap. |
1993 |
|
| Authors:
Michael E. Thomas; William J. Tropf; Summer L. Gilbert; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Ultraviolet optical properties near the edge of transparency (just above and below the band gap) of polycrystalline ALON (aluminum oxynitride, Al(23)O(27)N(5)) and spinel are not well characterized. The edge of transparency is commonly found to obey Urbach's rule, and this is the case for single-crystal sapphire and polycrystalline ALON and spinel as well. Room-temperature transmission and reflection measurements are made from 2500 to 1150 A on these materials and the ... |
|
| Performance of Low-Cost Commercial Fiber-Optic Transceivers for Reference Frequency Distribution |
Dec-1992 |
14 pages |
| Authors:
Richard Dragonette; Joseph J Suter; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Precision time and frequency reference signals have been effectively disseminated using high-quality intricate fiber-optic distribution systems. The quality of signals distributed by such systems is excellent, but the cost of these systems makes them unavailable to many potential users. In this paper, a study of signal quality maintained using inexpensive commercial transmitter/receiver pairs is undertaken. Seven different transmitter/receiver pairs obtained from four different manufacturers have been thoroughly tested using a ... |
|
| Hyperbaric Oxygen Therapy in the Management of Partial and Full Thickness Burn Injuries |
29 SEP 92 |
2 pages |
| Authors:
Lawrence J. Gottlieb; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| A New Model for Interpreting Experimental Data from a Circular Waveguide Cavity |
07 AUG 92 |
20 pages |
| Authors:
William A. Huting; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Progress is described in the testing of circular TE 01, waveguide using a resonant cavity technique. A new model has been developed for extrapolating insertion loss values from experimental cavity Q data. This model is compared with a previous model, and experiments are described that involve both cavities with mechanically adjustable lengths and cavities with fixed lengths. Data are also presented for waveguide bend cavities. In all cases, the extrapolated ... |
|
| Evaluation of Several Biological Monitoring Techniques for Hazard Assessment of Potentially Contaminated Wastewater and Groundwater. Volume 2. Aberdeen Proving Ground Wastewater Treatment Plant |
JUL 92 |
136 pages |
| Authors:
Dennis T. Burton; Randall S. Herriott; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An evaluation of several biological monitoring techniques for hazard assessment of potentially contaminated effluent was conducted at the Aberdeen Proving Ground Wastewater Treatment Plant (APG-WWTP), Aberdeen Proving Ground, MD, from early May 1990 to February 13, 1991. An array of biomonitoring tests structured in a tiered hazard assessment framework was used in the evaluation of the effluent. Several levels of biological organization were included in the array of tests. Acute ... |
|
| Evaluation of Several Biological Monitoring Techniques for Hazard Assessment of Potentially Contaminated Wastewater and Groundwater. Volume 1. Aberdeen Proving Ground-Edgewood Area Wastewater Treatment Plant |
JUL 92 |
100 pages |
| Authors:
Dennis T. Burton; William C. Graves; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An evaluation of several biological monitoring techniques for hazard assessment of potentially contaminated effluent was conducted at the Aberdeen Proving Ground-Edgewood Area Wastewater Treatment Plant (APG-EA WWTP), Aberdeen Proving Ground, MD, from January 1989 to December 13, 1989. An array of biomonitoring tests structured in a tiered hazard assessment framework was used in the evaluation of the effluent. Several levels of biological organization were included in the array of tests. ... |
|
| Thermal Shock Capabilities of Infrared Dome Materials. |
JUL 1992 |
|
| Authors:
J. S. Lin; L. B. Weckesser; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Evaluation of Silicon Nitride as an Advanced Radome Material. |
JUL 1992 |
|
| Authors:
R. K. Frazer; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| A Wave Theory for Non-imaging Concentrators |
APR 92 |
26 pages |
| Authors:
William H. Carter; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An expression is derived for propagation of the radiance function for light in any state of coherence through a concentrator that can be represented by a linear, stationary optical system. For light from a quasi-homogeneous source, this expression can be somewhat simplified by an approximation. It is shown that the radiance function is invariant for a large class of optical systems. It is also shown that fundamental limitations for the ... |
|
| Large-Scale System Performance Prediction with Confidence from Limited Field Testing Using Parameter Identification. |
APR 1992 |
|
| Authors:
L. J. Levy; D. W. Porter; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Using Statistics to Assess the Performance of Neural Network Classifiers. |
APR 1992 |
|
| Authors:
L. V. Hutton; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Unwrapping Two-Dimensional Phase Data in Contour Maps |
MAR 92 |
17 pages |
| Authors:
William H. Carter; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| A computer algorithm has been discovered for unwrapping two- dimensional Phase data and producing perfect contour maps without holes or dark bands of erroneous contour lines. The method employs local, temporary unwrapping within single grid squares of rectangular sampled data and the addition of extra contour levels outside the 0 to 2 pi range to fill holes. Phase Unwrapping, Contour Mapping, Phase Retrieval, Electromagnetic Fields. |
|
| U.S. Army Biomedical Research and Development Laboratory Aquatic Biomonitoring Trailer Version 1.0: Operations Manual |
MAR 92 |
97 pages |
| Authors:
Randall S. Herriott; Dennis T. Burton; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The U.S. Army Biomedical Research and Development Laboratory (USABRDL) Aquatic Biomonitoring Trailer Version 1.0 is a mobile laboratory which employs several biological biomonitoring systems for hazard assessment of potentially contaminated wastewater, complex effluents, and groundwater. This operations manual has been designed to provide a specific overview of the Aquatic Biomonitoring Trailer. Included in the manual is a general description of the trailer; initial utility, diluent water, test material, and waste ... |
|
| Evaluation of Several Biological Monitoring Techniques for Hazard Assessment of Potentially Contaminated Wastewater and Groundwater. Volume 3. Old O-Field Groundwater |
MAR 92 |
225 pages |
| Authors:
Dennis T. Burton; Steven D. Turley; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The toxicity of contaminated Old O-Field (Edgewood Area of Aberdeen Proving Ground) groundwater and the reduction and/or elimination of toxicity by various treatment processes were evaluated. The study was divided into a bench scale and pilot scale study. The bench scale studies consisted of 48-h definitive acute toxicity tests run with daphnid neonates (Daphnia magna) and juvenile fathead minnows (Pimephales promelas) exposed to untreated Old O-Field groundwater and groundwater treated ... |
|
| Optical Switches Based on Semiconducting Vanadium Dioxide Films Prepared by the Sol-Gel Process, |
MAR 1992 |
|
| Authors:
Richard S. Potember; Kenneth R. Speck; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Vanadium dioxide thin films have been grown from vanadium tetrakis (t-butoxide) by the sol-gel process. A new method for the synthesis of the vanadium precursor was also developed. Films were deposited by dipcoating glass slides from an isopropanol solution, followed by postdeposition annealing of the films at 600 degC under nitrogen. The properties of these films, to a high degree, were a function of crystalline boundaries and crystalline grain size. ... |
|
| Topex Spacecraft Dual-Frequency Radar Altimeter Antenna, |
FEB 1992 |
|
| Authors:
Allan R. Jablon; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The design of the TOPEX Radar Altimeter antenna is described. The TOPEX/POSEIDON satellite is a joint U.S.-France (NASA-CNES) spacecraft scheduled for launch in 1992. The spacecraft will carry the TOPEX and POSEIDON radar altimeters, which will map the circulation of the global oceans. The TOPEX radar altimeter (NASA) is a dual-frequency altimeter operating at Ku- and C-bands. The POSEIDON radar altimeter (CNES) operates at Ku-band. A common antenna is used ... |
|
| Typhon - A Weapon System Ahead of Its Time. |
JAN 1992 |
|
| Authors:
M. Gussow; E. C. Prettyman; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Fleet Air Defense - Countermeasures. |
JAN 1992 |
|
| Authors:
W. C. Hyatt; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| Search Radar Automation - AN/SYS-1 and Beyond. |
JAN 1992 |
|
| Authors:
G. F. Emch; G. I. Kirkland; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
|
| CHARACTERIZATION OF COMPOSITES USING AN ANGLE SAMPLE BENDING TEST FIXTURE. Part I - Thin Laminates Using Low Modulus Graphite/Epoxy Fabric |
92 |
|
| Authors:
J. C. Roberts; P. J. Biermann; P. D. Wienhold; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| A test has been devised for characterizing the failure loads on composite angles layed-up on a small radius tool. The inside radius on 90 deg angle samples made of 207 GPa(20 x1000000 psi) graphite/epoxy fabric prepreg was varied from 0.025mm to 6.36mm. Thin 2 ply samples were tested in an opening mode(where the angle between the legs opened toward 180 deg) and a closing mode(where the angle between the legs ... |
|
| Effect of Fiber Nonlinear Elasticity on the Temperature and Stress Dependence of Young's Modulus of Continuous Fiber Composites |
92 |
|
| Authors:
Paul D. Weinhold; R. K. Eby; John M. Liu; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The following report contains the effect of the nonlinear elasticity of carbon fibers on the axial young's modulus of an uniaxial composite. an equation to predict the axial young's modulus and its change with temperature has been obtained from previous work on a metal matrix composite. the equation covers the thermal strains generated in the fiber and the matrix mismatch of thermal expansion, the nonlinear elasticity of the constituent, and ... |
|
| High Temperature Optical Properties of Oxide Dome Materials. |
1992 |
|
| Authors:
Raymond M. Sova; Milton J. Linevsky; Michael E. Thomas; Frank F. Mark; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| A vacuum emissometer utilizing a CO(2) laser for high temperature sample heating has been designed and built for use with a Fourier Transform spectrometer. A two-color pyrometer technique is used to calculate sample temperatures. Oxides such as sapphire, spinel, yttria, ALON and fused silica experimentally characterized from 600 to 2000 K and from 500 to 5000 cm(-1). A glowing yttria sample has also been characterized over the spectral range of ... |
|
| Models of the Optical Properties of Solids. |
1992 |
|
| Authors:
William J. Tropf; Michael E. Thomas; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Physical-based optical property models of solids are a convenient means of representing the complex index of refraction as a function of frequency and temperature. This modeling approach is especially convenient considering the wide spread use of personal computers and the uncomplicated mathematical form of the models. Models provide a convenient method of cataloging measurements and interpolated between measurements. Several useful models convering absorption and scattering phenomena are presented. Together, these ... |
|
| Electromagnetic Interference (EMI) Shielding of Thin Graphite/Epoxy Composite Plates. |
1992 |
|
| Authors:
Jack C. Roberts; Paul D. Weinhold; Donald L. Kirkbride; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Samples of several material combinations were tested for electro- magnetic interference (EMI) shielding effectiveness over the frequency range from 0.2-40 GHz using a dual chamber test method. The samples tested consisted of 203 mm (8 inches) square panels. The materials tested were, a solid aluminum plate 0.76 mm (.030 inch) thick for control and thin (3 ply) graphite/epoxy fabric laminates that had been: (1) plated with 0.051 mm (.002 inch) ... |
|
| Electromagnetic Interference (EMI) Shielding of a Thin Nickel Plated Graphite/Epoxy Composite Aperture With Different Gasket Materials. |
1992 |
|
| Authors:
Jack C. Roberts; Paul D. Weinhold; Donald L. Kirkbride; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Test panels representative of the geometry of an electronics enclosure/ cover interface were fabricated using graphite/epoxy fabric pre-preg. The two panels, molded to incorporate the shape of a typical indented cover and enclosure flange, were then Ni plated. The aperture formed by the two parts was assembled with three conventional gasket designs and electromagnetic interference (EMI) tests were run over the frequency range of 0.2-40 GHz. The gaskets consisted of: ... |
|
| A Correlational Analysis of the Effects of Changing Environmental Conditions on the NR Atomic Hydrogen Maser |
Dec-1991 |
10 pages |
| Authors:
R A Dragonette; J J Suter; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An extensive statistical analysis has been undertaken to determine if a correlation exists between changes in an NR atomic hydrogen maser's frequency offset and changes in environmental conditions. Data have been acquired over the past 20 months by recording the frequency offset of three NR atomic hydrogen masers along with the relative and absolute humidity, barometric pressure, and ambient temperature of the laboratory in which the masers are maintained. Correlational ... |
|
| Solar Vector Magnetic Field Research |
30 NOV 91 |
26 pages |
| Authors:
David M. Rust; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Observations have been made before and after a large solar flare. Magnetic features were observed that could be used to predict flares it they are a regular feature of such events. The observations were among the first to show the development of shear within one hour of flare onset. Observations of linear polarization have been made of transient brightenings at small points in the lower chromosphere. The association between these ... |
|
Reports by Corporate Author
