| A Physical Model of Human Skin and Its Application for Search and Rescue |
Dec-2009 |
|
| Authors:
Abel S Nunez; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
 | For this research we created a human skin reflectance model in the VIS and NIR. We then modeled sensor output for an RGB sensor based on output from the skin reflectance model. The model was also used to create a skin detection algorithm and a skin pigmentation level (skin reflectance at 685nm) estimation algorithm. The average root mean square error across the VIS and NIR between the skin reflectance model ... |
|
| A Feasibility Study of RF Time-Domain Reflectometry as a Railgun Armature Tracking Technique |
08 AUG 2007 |
13 pages |
| Authors:
S. Levinson; F. Stefani; E. Snyder; TEXAS UNIV AT AUSTIN INST FOR ADVANCED TECHNOLOGY
|
 | Since past investigations have shown that radio frequency (RF) signal transmission in the bore of a railgun can be practical, the feasibility of using time domain reflectometry and well-established transmission line theory is investigated as a means to determine armature position during launch. This report describes the transmission line model of the HEMCL and initial measurements suggesting that such an approach might be used to provide dynamic armature position profiles. ... |
|
| Materials on the International Space Station Experiment (MISSE): Optical Analysis of Molecular Contamination on PEC1 Tray 2 |
20 FEB 2007 |
21 pages |
| Authors:
P. D. Fuqua; C. J. Panetta; J. D. Barrie; AEROSPACE CORP EL SEGUNDO CA
|
| Silicon wafers were mounted on the exterior of the International Space Station as a part of MISSE. Post-flight ellipsometry and reflectometry were employed to show that the silicon wafers gained about a 420-A-thick layer of a silica-like contaminant with BRDF scatter values around 1 x l0% per steradian. |
|
| Selection Criteria of Test Signals for Correlation-Based Wire Fault Analysis (Preprint) |
MAY 2006 |
10 pages |
| Authors:
Venkata Telasula; Cynthia Furse; Chet Lo; UTAH UNIV SALT LAKE CITY DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| This paper compares reflectometry signals for location of intermittent faults on live electrical cables. STDR, SSTDR, linear chirp, quadratic chirp, concave-up chirp, convex-down chirp and all frequency randomized phase noise signals were tested. The SSTDR was observed to be the most effective signal for live wire testing, because of its minimal interference with the existing signals and narrow correlation signature. This paper provides a methodology for systematically evaluating signal performance ... |
|
| Reflection Properties of Scarabaeidae |
AUG 2005 |
10 pages |
| Authors:
Dennis H. Goldstein; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Beetles of the scarab family have been found to reflect circularly polarized light from incident unpolarized light. There are many known animals that use polarized light in some form and several that actually create it, but there are few examples of the creation of circularly polarized light in nature. Previous work is summarized, and new measurements of several scarab specimens are presented. |
|
| Dielectric Non-Destructive Analysis of Adhesive Bonded Structures |
28 SEP 2004 |
148 pages |
| Authors:
Jovan Mijovic; POLYTECHNIC UNIV BROOKLYN NY
|
| An investigation was conducted aimed at developing dielectric spectroscopy as a non-destructive inspection tool to assess aging of adhesive bonded structures. Dielectric spectroscopy was found to be a sensitive tool capable of detecting defects and absorbed moisture in adhesive bonded structures. The highlights of the research performed are: l) The defects in adhesive joints decrease the real and imaginary dielectric permittivity in the frequency domain and induce additional peaks in ... |
|
| Grazing Angle Enhanced Backscattering from a Dielectric Film on a Reflecting Metal Substrate |
MAR 2004 |
11 pages |
| Authors:
Zu-Han Gu; I. M. Fuks; Mikael Ciftan; SURFACE OPTICS CORP SAN DIEGO CA
|
| The authors recently observed several features from a randomly rough dielectric film on a reflecting metal substrate, including a change in the spectrum of light at the satellite peaks, the high-order correlation, and enhanced backscattering from the grazing angle. In this paper, they focus on the enhanced backscattering phenomena. The backscattering signal at small grazing angles is very important for vehicle re-entrance and subsurface radar sensing applications. Recently, they performed ... |
|
| New Features of Scattering from a Dielectric Film on a Reflecting Metal Substrate (Part 1) |
2004 |
14 pages |
| Authors:
Zu-Han Gu; I. M. Fuks; Mikael Ciftan; SURFACE OPTICS CORP SAN DIEGO CA
|
| The authors recently observed several features from a randomly rough dielectric film on a reflecting metal substrate, including a change in the spectrum of the light at the satellite peaks, the high-order correlation, and enhanced backscattering from the grazing angle. In this paper, they focus on the enhanced backscattering phenomena. The backscattering signal at small grazing angles is very important for vehicle re-entrance and subsurface radar sensing applications. Recently, they ... |
|
| Polarization Signature Research |
FEB 2003 |
87 pages |
| Authors:
Dennis H. Goldstein; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Documentation of work in Mueller matrix spectropolarimetry, Mueller matrix laser polarimetry, and near infrared imaging polarimetry is presented. Spectropolarimetric reflectometer instrumentation is described, and measurements made with this instrumentation on Spectralon and Federal Standard paint samples are given. Laser polarimeter measurements on sapphire and quartz plates with small birefringence are discussed. Results from an imaging near infrared rotating retarder Stokes polarimeter are presented. |
|
| Optical Frequency Domain Reflectometry for High Density Multiplexing of Multi-Axis Fiber Bragg Gratings |
2003 |
5 pages |
| Authors:
Stephen Kreger; Sean Calvert; Eric Udd; BLUE ROAD RESEARCH GRESHAM OR
|
| An interferometric fiber grating interrogation system utilizing a depolarized Erbium ring laser was used to interrogate transversely strained gratings written through the polyimide coating with 1 mm spatial resolution, and the interferometric results were compared to waveforms taken using a broadband source and OSA. |
|
| Radar and Infrared Sensors for Landmine Detection |
30 JUN 2001 |
3 pages |
| Authors:
Brian Borchers; NEW MEXICO INST OF MINING AND TECHNOLOGY SOCORRO
|
| In this project, sensors for land mine detection research were purchased. The sensors included a ground penetrating radar system operating at 1200 Mhz, as well as a long wave IR camera. A weather station and time domain reflectometry system for monitoring soil water content were also purchased. The sensors have been used in support of an ongoing research program in modeling soil physical properties and their effect on the performance ... |
|
| A Proposal for the Purchase of SOC-500 Laser Interferometric Monostatic Reflectometer |
25 MAY 2001 |
4 pages |
| Authors:
Zu Han Gu; Alexei A. Maradudin; CALIFORNIA UNIV IRVINE
|
| Two Instruments: (1) Correlation Measurement Unit, (2) Photon Correlate Function Measurement Unit have been constructed under the grant and are now operational. These will be used to various modes of scattering of coherent and partially coherent light forms, including speckle fatterous produced therefore. Applications will include finger-printing' for pattern recognition and discrimination, future hit-to-kill' interceptors and real-time imaging of threat targets. |
|
| Sensor Technology for Weather and Terrain |
SEP 2000 |
31 pages |
| Authors:
Andrew W. Harrell; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL LAB
|
| The purpose of this report is to review weather effects on soil moisture and combat engineering. It considers current means of obtaining soil moisture information from weather models, surface observation reports, and remote sensing sources. The methodologies used for different types of ground moisture probes, and, in particular, time domain reflectometers (TDR) are explained. It also explains how the measurements that the TDR probes give ... |
|
| POTDR Measurements on Buried Optical Fibers |
14 AUG 1998 |
22 pages |
| Authors:
Kent B. Hill; Carl A. Villarruel; NAVAL RESEARCH LAB WASHINGTON DC ADVANCED CONCEPTS BRANCH
|
| In this report, a polarization-sensitive optical time domain reflectometer (POTDR) is described and results of POTDR measurements on buried optical fibers in a network testbed are presented. The polarization effects observed on different fibers in the testbed show that the birefringence may vary significantly in fibers of the same type and the same cable. Measurements taken over several hours indicate that polarization effects in buried optical ... |
|
| Length and Elongation Sensor |
07 APR 1998 |
|
| Authors:
Louis E. Sansone; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A length and elongation sensor includes an elastomeric optical wave guide and a time domain reflectometer. The elastomeric optical wave guide consists of a urethane outer cladding and an optical gel core. A transparent window is hermetically sealed to the first end of the optical wave guide and a reflective mirror is hermetically sealed to the second end of the optical wave guide. Both ends of the wave guide are ... |
|
| Passive Intrusion Detection System. |
06 JAN 1998 |
|
| Authors:
Dopuglas H. Wilson; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An RF energy source transmits energy into a transmission cable that has a characteristic impedance subject to change by deformation of the cable. The cable is buried along a path that corresponds to a perimeter to be monitored. When an intruder places weight in the vicinity of the cable the cable deforms and changes its characteristic impedance. Consequently a portion of energy transmitted into the cable reflects back where time-domain ... |
|
| Soil Moisture Determinations Using Capacitance Probe Methodology |
JAN 1998 |
49 pages |
| Authors:
Ronald T. Atkins; Timothy Pangburn; Roy E. Bates; Bruce E. Brockett; COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
|
| Determining soil moisture content by measuring the dielectric constant of the soil is not a new concept. However, determining the dielectric constant by measuring capacitance directly rather than through the use of time domain reflectometry (TDR) systems is a relatively new approach to soil moisture measurements. A unique probe assembly and a readout device that measures voltage drop and phase shift were developed and used for direct capacitance measurements. The ... |
|
| Additional Soil Evaluations at Yuma Proving Ground |
15 DEC 1997 |
|
| Authors:
James L. Kurtz; jason Cowdery; Mary E. Collins; FLORIDA UNIV GAINESVILLE ELECTRONIC COMMUNICATIONS LAB
|
| On September 23 and 24, 1997 tests were performed by the University of Florida on soils at Phillips Drop Zone in Yuma Proving Ground, Arizona. Soil Samples were also collected and additional tests were later made in the laboratory in order to characterize the soil properties. These tests were performed for the Army Research Laboratory. The objectives of this effort were primarily to characterize the soil conditions, particularly moisture and ... |
|
| Scattering From Dielectric Bodies |
DEC 97 |
296 pages |
| Authors:
Jeffery M. Parks; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
|
| The purpose of this study was to develop an RCS measured database of non-PEC targets and provide an example of its use to validate a code, 3D-RCIE. RCS prediction codes that handle penetrable materials require measured data to determine their accuracy. The materials used for this research include polyethylene and polyurethane with dielectric constants around 2.3 and 1.03, respectively. The polyethylene targets include a mini-arrow, ogive, conesphere, conesphere with a ... |
|
| Time-Domain Reflectometry of Water Content in Portland Cement Concrete |
NOV 97 |
20 pages |
| Authors:
Charles J. Korhonen; Vincent C. Janoo; Christopher M. Berini; COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
|
| Time-domain reflectometry is useful for measuring the moisture content of solids. However, little information exists on its use with Portland cement concrete. By monitoring the response from TDR sensors embedded in concrete as the concrete dried, we developed a second-order polynomial equation that relates dielectric constant to moisture content. The study is valid for the specific concrete studied. |
|
| Enhancing Clark Atlanta University Participation in Defense Research, Volumes 1 and 2 |
30 JUN 1997 |
213 pages |
| Authors:
Kofi B. Bota; CLARK ATLANTA UNIV GA
|
| The Army-supported research program focused on interdisciplinary research areas in environmental technologies: flow, structures and materials, and software engineering. The program aimed at enhancing CAU's research capabilities, through development of resources and facilities (including equipment and personnel) in areas relevant to the Department of Defense. Several projects were executed to develop expertise and research programs that fall within the mission goals and program objectives of the Department of Defense. ... |
|
| Growth, Characterization and Device Development in Monocrystalline Diamond Films |
JUN 1997 |
44 pages |
| Authors:
R. F. Davis; R. J. Nemanich; Z. Sitar; P. Baumann; W. Liu; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Highly oriented diamond has been grown on (100) Ni substrates by the hot filament chemical vapor deposition method. Epitaxial nuclei were obtained by diamond powder seeding and a subsequent high-temperature annealing process. Real time, in situ laser reflectometry was developed to monitor changes in surface morphology observed during the high temperature annealing since the timing of the process was crucial for the achievement of a high degree of orientation and ... |
|
| The USAF Manufacturing Technology Program Status Report, Fall 1997 |
97 |
16 pages |
| Authors:
WRIGHT LAB WRIGHT-PATTERSON AFB OH MANTECH TECHNOLOGY TRANSFER CENTER
|
| A Wright Laboratory Manufacturing Technology Directorate-sponsored project has developed new instrumentation for in-line wafer-state diagnostics and process control for semiconductor fabrication which could result in significant savings when fully implemented. The significance of this achievement was recognized by R&D Magazine, when the instrument received the 1996 'R&D 100' award, for being one of the 100 most technologically significant new products developed over the year. This award has been given over ... |
|
| Low-Emissivity Camouflage Coatings |
JUN 96 |
|
| Authors:
Kestutis G. Chesonis; Donovan Harris; ARMY RESEARCH LAB FORT BELVOIR VA
|
| The next generation of low-emissivity camouflage coatings will have signature modulating properties in the infrared (IR) bands without sacrificing the visual and near-IR properties and its chemical agent resistant coatings (CARC) nature. This report outlines the major problems facing the coatings chemists/formulators and the use of new instrumentation to define development and evaluation of coating surfaces by particle-size distribution and profile. There are four bands in the electromagnetic spectrum that ... |
|
| Static and Mobile Polymer Surfaces of Well Defined Structure. |
15 NOV 1995 |
6 pages |
| Authors:
William J. Brittain; Wayne L. Mattice; Mark D. Foster; AKRON UNIV OH
|
| Photoresponsive monolayers were prepared by the chemisorption of azobenzene-containing molecules to silicate substrates. A reversible change in the water contact angle was observed upon UV irradiation. Neutron reflectometry was used to probe protein adsorption to monolayers. The adsorption of human serum albumin was observed for amine- and methyl-terminated monolayers. Molecular dynamic simulations indicated directions for the next generation of synthetic efforts; the ideal placement for the azobenzene group is near ... |
|
| Surface Segregation of Tackifier in Pressure Sensitive Adhesives. |
OCT 1995 |
3 pages |
| Authors:
Mark D. Foster; AKRON UNIV OH
|
| The project as finally funded was cast in the form of a proof-of- concept study with a narrow focus. The objective was to demonstrate the feasibility of characterizing tackifier concentration depth profiles in pressure sensitive adhesive films and correlating these profiles with adhesive performance. Thin films of isoprene and mixed with various amounts of an abietic acid ester tackifier were studied using a combination of neutron reflectometry (NR), forward recoil ... |
|
| Transducer Workshop (18th) Held in Colorado Springs, Colorado on 20-22 June 1995 |
JUN 95 |
375 pages |
| Authors:
RANGE COMMANDERS COUNCIL WHITE SANDS MISSILE RANGE NM
|
| This document contains papers presented at the Eighteenth Transducer Workshop. This document has been published for information purposes only. The material contained herein does not necessarily represent the position or conclusions of the Range Commanders Council. |
|
| 5-Picosecond Photoconductive Sampling Oscilloscope |
14 APR 95 |
|
| Authors:
Steven Williamson; PICOTRONIX INC ANN ARBOR MI
|
| During our Phase I SBIR we developed a novel laser-driven picosecond sampling photogate that has 5-picosecond temporal resolution and 10-microvolt sensitivity. The sampling gate system is evaluated and applied to several testing environments. To improve the sensitivity further, and lower the required excitation light level, we use a high-impedance transimpedance preamplifier stage. This amplifier permits us to measure signals down to 1 microvolt using less than 10 microwatts of average ... |
|
| Characterization of Material Properties at Terahertz Frequencies |
1995 |
12 pages |
| Authors:
Robert H. Giles; MASSACHUSETTS UNIV LOWELL SUBMILLIMETER-WAVE TECH LAB
|
| In the realm of materials science, terahertz frequency measurement systems provide significant utility in the characterization of material properties. With support primarily from the U.S. Army National Ground Intelligence Center (NGIC), Submillimeter Technology Laboratory (STL) researchers have been advancing the field of terahertz technology to the application of modeling millimeter-wave and microwave radar for more than a decade. Research in modeling radar requires design of a wide range of measurements ... |
|
| Development of a Portable Ice-Thickness Measuring Instrument |
14 MAR 94 |
19 pages |
| Authors:
John C. Joseph; Dennis P. Glenn; Philip J. Joseph; DEDICATED ELECTRONICS INC CHESTER NH
|
| A portable instrument that can be manually placed in contact with the surface of an ice-covered body of water to non-obtrusively measure the ice thickness was developed. The instrument design is based on determining ice thickness from microwave frequency signals which are transmitted through the ice and reflect from the ice/water interface. Prior methods include drilling through the ice to manually measure its thickness and using radar equipment which is ... |
|
| Enhanced Backscattering from Rough Surfaces |
DEC 92 |
21 pages |
| Authors:
Zu-Han Gu; SURFACE OPTICS CORP SAN DIEGO CA
|
| We have been conducting a combined theoretical and experimental research program in the field of enhanced backscattering from randomly rough metal and dielectric surfaces. The principal goal of this study is to improve our understanding of the mechanism responsible for the enhanced backscattering phenomenon. At the same time, the results we obtained will apply to remote sensing and radar clutter research.... Enhanced backscattering, Electromagnetic wave, Scattering, Statistical optics, Remote sensing. ... |
|
| Centimeter Wave Absorption in Molecular Crystals |
SEP 92 |
29 pages |
| Authors:
Steve G. Cornelison; Arthur Gauss Jr.; Robert B. Bossoli; H. M. Lu; J. R. Hardy; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Molecular dynamics calculations performed at the University of Nebraska predict that temperature-dependent microwave activity is present in some ionic molecular crystals. This activity is due to the excitation of 'hindered rotations' or thermally activated 'hopping' modes for the molecular ions. Microwave reflectometer measurements performed at the BRL show temperature-dependent microwave losses occur in several ionic molecular crystals at or near the calculated order/disorder transition temperatures. These measurements, performed from 2 ... |
|
| OTDR in Optical Amplifier Transmission Systems Using EDFAs Containing Optical Circulators, |
22 MAY 1992 |
|
| Authors:
Yoshiaki Sato; Shigendo Nishi; Koh-ichi Aoyama; NIPPON TELEGRAPH AND TELEPHONE CORP TAKE TRANSMISSION SYSTEMS LABS
|
| Optical time domain reflectometry (OTDR) is an effective technique for locating breaks and for determining the loss distribution along a fiber 12. However, OTDR can not be used with optical transmission lines containing traditional Er-doped fiber amplifiers (EDFAs) because EDFAs require optical isolators to eliminate signal reflection (3)-(5). The returning backscattered light generated by the forward traveling probe pulse is blocked by optical isolators in each EDFA. In this paper, ... |
|
| In SITU Measurement of the Dielectric Properties of Ceramics with a Single Mode Microwave Heating Device, |
27 APR 1992 |
|
| Authors:
X. D. Yu; V. V. Varadan; V. K. Varadan; D. Ghodgaonkar; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| A single mode microwave heating device which operates at 2.45 GHz was modified to simultaneously heat and characterize ceramic materials. The equivalent circuit derived by Marcuvitz 9 to model the ceramic rod in the waveguide was used in the formulation. Three crystal detectors on the impedance analyzer were used as a reflectometer to measure the reflection coefficient of the load, so that transmission line measurements can be automated. The measured ... |
|
| Development of a 600 Meter Chirp Sonar |
26 MAR 92 |
|
| Authors:
FLORIDA ATLANTIC UNIV BOCA RATON DEPT OF OCEAN ENGINEERING
|
| This letter is the final technical report for Grant No. N00014-90-J- 4134 which expired 27 September 1991. This grant was entitled the Development of a 600 Meter Chirp Sonar. The chirp sonar is a digital FM reflection profiler that generates high signal to noise, quantitative data useful for imaging the seabed and estimating sediment properties. The objective of this project is to develop a chirp sonar for the Naval Oceanographic ... |
|
| Status of the Soft X-Ray/XUV Optical Metrology Program at the National Institute of Standards and Technology, |
05 MAR 1992 |
|
| Authors:
Richard Watts; David Ederer; Thomas Lucatorto; Charles Tarrio; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
|
| The National Institute of Standards and Technology (NIST) has initiated a program devoted to the characterization of soft x-ray optics at the wavelength of use. Although NIST has an operational XUV characterization facility which it is using to make measurements for users across the country, that facility suffers from several deficiencies that will limit its usefulness in the coming years. Therefore, we are constructing an improved monochromator/ reflectometer beamline that ... |
|
| Interfacial Roughness and Interdiffusion Derived from a Comparison of the Measured and Calculated Reflectances of Mo/Si Multilayer Coatings, |
05 MAR 1992 |
|
| Authors:
J.F. Seely; M.P. Kowalski; T.W. Barbee; J.C. Rife; W.R. Hunter; NAVAL RESEARCH LAB WASHINGTON DC
|
| Mo/Si multilayer coatings were fabricated at LLNL and were characterized using the Grating/Crystal Monochromator and Reflectometer attached to the Naval Research Laboratory beamline X24C at the National Synchrotron Light Source. The reflectances were measured at several angles of incidence and for both s and p polarizations. The measured reflectances were compared to calculations that included the effects of interdiffusion layers and of roughness at each interface and that were based ... |
|
| A Spectroscopic Differential Reflectometry Study of (100), (110), (111), (311), and (511) Silicon Surfaces |
06 DEC 90 |
|
| Authors:
S. Chongsawangvirod; E. A. Irene; NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF CHEMISTRY
|
| Spectroscopic Differential Reflectometry, SDR, has been applied to study differences in silicon surfaces with different crystallographic orientations and with very thin films. The SDR technique measures the normalized difference in reflectance of two adjacent samples in the spectral range of 250- 800 nm near normal incidence. This study demonstrates the surface sensitivity of the SDR technique to the Si crystal orientations, and to the presence of thin oxide films on ... |
|
| Ultrafast Optical Electronics Center |
28 AUG 90 |
|
| Authors:
Gerard Mourou; ROCHESTER UNIV NY LAB FOR LASER ENERGETICS
|
| The work done under the URI had the mission to bridge ultrafast optics with high-speed electronic and photonics. Ultrashort optical pulses have been used to study of fundamental processes taking place in the femtosecond and picosecond timescales in bulk and layered semiconductors, metals, and superconductors. Under this contract electron velocity overshoot in GaAs was time-resolved for the first time. Using short optical and electrical pulses, both sequential and resonant tunneling ... |
|
| Calibrated Bender for Fiber Optic Cable Position Determination. |
26 JUN 1990 |
|
| Authors:
Willard Stevenson; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| Two sets of cylindrical fingers disposed in an interdigital relationship are pivoted together, scissors fashion, to receive a portion of an optical fiber cable. When the fingers are rotated to a closed position, they create a predetermined series of bends in the portion of the optical fiber cable that can be observed by an optical time domain reflectometer. This observation allows a remote monitor to determine the relative location of ... |
|
| Integrated Controls and Health Monitoring Fiberoptic Shaft Monitor. Task E.5 , Amendment 3 |
NOV 89 |
|
| Authors:
P. Coleman; J. Collins; H. Darejeh; ROCKWELL INTERNATIONAL CANOGA PARK CA ROCKETDYNE DIV
|
| Recent work has been carried out on development optical technology to provide real time monitoring of shaft speed, shaft axial displacement and shaft orbit of the OTVE hydrostatic bearing tester. Results show shaft axial displacement can be optically measured (at the same time as shaft orbital motion and speed) to within 0.3 mills by two fiberoptic deflectometers. This paper presents the final results of this condition monitoring development effort. ... |
|
| Composite Integrity Monitoring |
MAY 89 |
79 pages |
| Authors:
Robert Rudd; Kim Goddard; SIMMONDS PRECISION PRODUCTS INC VERGENNES VT INSTRUMENT SYSTEMS DIV
|
| Optical fibers were embedded in graphite epoxy composite coupons and I-beams with the objective of measuring integrated and distributed loads. Polarimetric techniques using both high and low birefringence optical fibers were used for integrated strain, while optical time domain reflectometry (OTDR) was used for locating distributed point loads. Polarimetric results agreed favorably with resistance strain gage data when the structure applied load normal to the optical fiber axis. Stresses of ... |
|
| Measurement of the Unfrozen Water Content of Soils. Comparison of NMR (Nuclear Magnetic Resonance) and TDR (Time Domain Reflectometry) Methods |
OCT 88 |
|
| Authors:
Michael W. Smith; Allen R. Tice; COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
|
| The results of a laboratory testing program, carried out to compare two independent methods for determining the unfrozen water content of soils, are described. With the time domain reflectometry method, the unfrozen water content is inferred from a calibration curve of apparent dielectric constant vs volumetric water content, determined by experiment. Previously, precise calibration of the TDR technique was hindered by the lack of a reference comparison method, which nuclear ... |
|
| Phase-Shift Parameters and Small Vibrations in Resonant Optical Cavities |
SEP 87 |
|
| Authors:
D. M. Ross; C. Brune; C. D. Marrs; NAVAL WEAPONS CENTER CHINA LAKE CA
|
| An exact analysis has been performed on a three-mirror passive cavity reflectometer. |
|
| Development of NbN Josephson Junction Technology |
24 JUL 86 |
|
| Authors:
M. Radparvar; HYPRES INC ELMSFORD NY
|
| A novel process suitable for fabrication superconducting circuitry based on the all refactory material NbN is described. In this process, and in- situ trilayer film composed of NbN/MgO/NbN is used to fabricate Josephson tunnel junctions. Reactive ion etching processes are used to delineate devices and pattern insulators and metallizations. Fabricated junctions have yielded good tunneling characteristics with reasonable current density uniformity and reproducibility. Devices with gap voltages close to 3mV ... |
|
| A Theoretical Study of Calibration Procedures for Coherent and Non- Conherent Polarimetric Radars |
JUN 86 |
|
| Authors:
M. A. Wood; ROYAL SIGNALS AND RADAR ESTABLISHMENT MALVERN (ENGLAND)
|
| A theoretical study has been made of calibration methods for both coherent and non-coherent polarimetric radars. Coherent systems are described in terms of measurement of the scattering matrix and non-coherent in terms of the Mueller Matrix. The similarity with the calibration of vector reflectometers is emphasized and exploited. Calibration is achieved by measuring the receiver voltages corresponding to scattering of the transmitted states by an odd bounce reflector and appropriately ... |
|
| Particle Sizing in a Solid Rocket Motor Using the Management of Scattered Light |
MAR 85 |
|
| Authors:
K. Abubakar; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A previous study discussed the formulation of the theory for the scattering properties in the general case of particles of arbitrary size and refractive index occurring in a polydispersion of finite optical depth. Roberts and Webb concluded that thee volume-surface mean diameter (Sauter) D sub 32 of the polydispersion may be determined from the intensity of diffraction scattered light from spherical particles. An experimental investigation was conducted to determine the ... |
|
| Open Water and Thin Ice Detection in the Arctic Marginal Ice Zone Using Reflectometer Signal Analysis |
MAR 1983 |
|
| Authors:
C. J. Radl; J. P. Welsh; NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY NSTL STATION MS
|
| Approximately 2000 kilometers (approx. 1250 statute miles) of reflectometer data collected within 160 kilometers (100 statute miles) of the ice edge in the North American Arctic were analyzed. The reflectometer signal, which shows a sharp decrease in areas of open water/thin ice, was used to initiate and develop a method to begin an evaluation of the frequency of occurrence and percentage of open water from the ice edge to approximately ... |
|
| Fiber Optic Cable Vulnerability Test, White Sands, New Mexico |
DEC 1982 |
|
| Authors:
S. F. Large; G. W. Styskal; MITRE CORP BEDFORD MA
|
| Tests were performed at the White Sands Missile Range, New Mexico, to evaluate the response of buried fiber optic cables to the accelerations and stresses developed by an explosive charge. During these tests, observations were made of cable transmissivity characteristics that might be affected by these forces. Transmission bit error rate (BER) measurements were made to determine cable performance changes. (Author) |
|
| Computer Controlled Optical Time Domain Reflectometer Monitoring of Lightguide Cable Installations, |
NOV 1982 |
|
| Authors:
Arthur F. Judy; Robert E. Fangmann; Michael J. Swiderski; BELL TELEPHONE LABS INC NORCROSS GA
|
| A computer controlled Optical Time Domain Reflectometer was used to monitor and measure fiber loss during the first Bell System installation of lightguide cable using standard plowing methods. The tests showed that the plowing operation had no measurable effect on fiber loss. (Author) |
|
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REFLECTOMETERS
