The finite element solution formulation in time- and space- coordinates is extended to beam vibrations effected by a moving couple. This problem has direct application to gun motions analysis with an unbalanced moving projectile. The moving load, instead of being a time-dependent Dirac delta function as for the case of a moving concentrated force, is now the derivative of this Dirac delta function. This singular function does not present any difficulty due to the variational process employed....
Topics: DTIC Archive, Wu, J J, ARMY ARMAMENT RESEARCH AND DEVELOPMENT CENTER WATERVLIET NY LARGE CALIBER...
Surface velocity observations from the Canary Basin of the northeast Atlantic Ocean are studied with emphasis on the region of the Azores Current. Data are based on trajectories of 155 WOCE-standard Lagrangian surface drifters drogued at 15 m depth. Over 52,000 daily velocity estimates are available for the region 45 deg W, 25 deg N and 5 deg W, 45 deg N for July 1991 through March 1995. A clear view of the mean Azores Current emerges around 34 deg N with average speeds of approx. 10 cm/s and...
Topics: DTIC Archive, Brown, John E., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *OCEAN CURRENTS, *MIXED...
These proceedings include the Technical Evaluation Report, Keynote Address, and 41 papers from the Symposium sponsored by the NATO/RTO Human Factors and Medicine Panel, which was held in San Diego, California, USA from 19-21 October 1998. Rotary wing operations include military or civilian missions such as transport, medevac, and combat. A range of human factors problems may be implicated in helicopter mishaps, such as spatial disorientation or excessive workload. Furthermore, flying a...
Topics: DTIC Archive, NATO RESEARCH AND TECHNOLOGY ORGANIZATION NEUILLY-SUR-SEINE (FRANCE), *MILITARY...
Evaluators of imaging devices which use two dimensional, staring arrays of detector or display elements, such as Charge Transfer Devices (CTD) or flat panel displays, often assume that scene detail at spatial frequencies up to half the sample rate will necessarily be replicated accurately in the image. That is, they assume that providing two samples per displayed or resolved cycle meets all the criteria of the Sampling Theorem. This assumption is not correct. Solid state cameras and flat panel...
Topics: DTIC Archive, Vollmerhausen, Richard H., CENTER FOR NIGHT VISION AND ELECTRO-OPTICS FORT BELVOIR...
A SBIR Phase I project was undertaken by Delta Data Systems, Inc. and Neptune Sciences, Inc. which focused on feasibility issues relating to the development of a Marine Geographic Information System (MGIS) that could support Logistics Over the Shore (LOTS) planning and operational monitoring tasks. Significant feasibility issues such as interfacing with wave models and ancillary data integration were addressed and resolved in the Phase I effort. Phase I prototype MGIS proved that value added...
Topics: DTIC Archive, Risinger, Ferron, DELTA DATA SYSTEMS INC PICAYUNE MS, *SHORES, *SURF, *GEOGRAPHICAL...
This thesis studies a constellation of satellites that gives multiple continuous coverage of the whole earth. A computer program is described which helps to find the optimal configuration. In particular, performance of a twenty-four satellite constellation is analyzed for triple coverage and the results given. Constellations where the number of orbital planes equal the number of satellites (N=P) and constellations where N does not equal P are both analyzed. Circular orbits are assumed. The...
Topics: DTIC Archive, Suarez,Melchor Louis, CHARLES STARK DRAPER LAB INC CAMBRIDGE MA, *AREA COVERAGE,...
An improved global calibration was derived and image enhancement techniques developed to increase the image quality, sensitivity, and spatial resolution of maps from the Infrared Astronomy Satellite (IRAS) survey data. These goals were achieved by augmenting and extending GEISHA (Groningen Exportable IRAS High-resolution Analysis) system. A completely new calibration scheme using the zodiacal light emission as a standard candle has been designed and implemented. This calibration is better...
Topics: DTIC Archive, Wesselius, P R, KAPTEYN ASTRONOMICAL LAB GRONINGEN (NETHERLANDS), *INFRARED...
Cylindrical array antennas are attractive for applications requiring uniform 360 azimuthal pattern performance. For very low sidelobe or precise angle measurement designs, an accurate knowledge of the mutually coupled element pattern becomes important. In Part 1 of this report, a modal solution is presented for an element pattern in a periodic array of axial dipole radiators placed coaxially over a circular cylindrical ground. This solution avoids the problems associated with asymptotic...
Topics: DTIC Archive, Tomasic, Boris, ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY, *ANTENNA RADIATION...
The problem of recognizing structured patterns (object recognition) is being pursued on several fronts. The main thrust of the work involves the design of networks that store some notion of a relational model of an object and performs recognition via a version of graph matching. This approach is governed by the use of objective functions to both specify the network and the problem to be solved. The dynamics of the net thus carry out an optimization procedure. Key here is the incorporation into...
Topics: DTIC Archive, Gindi, Gene R, YALE UNIV NEW HAVEN CT, *PATTERN RECOGNITION, *NEURAL NETS, INPUT,...
The structure of spontaneous decay of atoms in the vicinity of a surface is shown to be determined by spatial symmetries. The spontaneous decay operator for a degenerate two level atom is derived, and with symmetry considerations the number of free parameters is reduced to two. Only the dimensionless and normalized inverse lifetimes b-parallel and b-perpendicular for a parallel and perpendicular dipole moment with respect to the surface, respectively, enter the expression for the relaxation...
Topics: DTIC Archive, Arnoldus, Henk F, STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY, *DIPOLE...
Orbital reentry of large maneuverable vehicles and the potential to modify orbital parameters using the aerobreaking technique have increased the need to understand in detail the variability of atmospheric density in the mesosphere and lower thermosphere. The variability of mass density in the mesosphere has been apparent for many years, being seen in sounding rocket data, backscatter radar profiles, and airglow optical emissions. The systematic variations that have been determined from these...
Topics: DTIC Archive, Hayes, P B, MICHIGAN UNIV ANN ARBOR SPACE PHYSICS RESEARCH LAB, *ATMOSPHERIC DENSITY,...
A general calculation of the spatial correlation function due to a distributed acoustic source near the water surface has been done previously using normal mode theory. In this paper a multiple ray path analysis is used to calculate the acoustic ambient vertical directivity function. Multipath propagation and ambient directional functions are physically intuitive concepts to underwater acoustic theory, and direct application of these notions has advantages in the interpretation of data....
Topics: DTIC Archive, Kennedy, Robert M, NAVAL UNDERWATER SYSTEMS CENTER WEST PALM BEACH FL, *UNDERWATER...
The relation between binaural perception of actual sounds in space and of stimuli presented over headphones, base on head-related transfer functions, showed a high correlation. Listeners reported that the sound image presented over headphones remained internal to the head and not external in space, as with natural sound. Head movement, context, bias, experience, and integration of information across senses remain probable contributions to externalizing headphone-delivered sounds at their...
Topics: DTIC Archive, Green, David M, NATIONAL RESEARCH COUNCIL WASHINGTON DC, *SYMPOSIA, *AUDITORY...
We are continuing our research in the development of the Inverse Scattering Transform (IST). IST is a method which allow's one to solve nonlinear wave equations by solving certain related direct and inverse scattering problems. Research is really two pronged. It is necessary for us to understand and effectively solve both classical and new direct and inverse scattering problems. We use these results to find solutions to nonlinear wave equations much like one uses Fourier analysis for linear...
Topics: DTIC Archive, Ablowitz, Mark J, COLORADO UNIV AT BOULDER, *INVERSE SCATTERING, *WAVE EQUATIONS,...
There are two tasks in this grant. The first is to develop a micromachined miniature polysilicon hot-wire anemometers with improved spatial resolution and frequency response. The finished device was a micron sized polysilicon wire supported by free-standing gold/silicon-nitride beams. These devices have time constants as small as a few microseconds and, under constant temperature mode, an unprecedented bandwidth of 1.4 N 4Hz was achieved measured in wind tunnel. The second task is to study...
Topics: DTIC Archive, Tai, Yu-Chong, CALIFORNIA INST OF TECH PASADENA DEPT OF ELECTRICAL ENGINEERING,...
This grant has supported the development of infrared interferometry, studies of atmospheric transmission and image distortion, and the resolution and study of stars and material surrounding them, with the general goal of improving astrometry and hence determination of stellar positions. Substantial progress has been made, including determination of atmospheric distortions of infrared transmission and its variation with time, altitude location of major atmospheric distortions, correlation of...
Topics: DTIC Archive, Townes, Charles H., CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE, *OPTICAL...
Tasks on this contract focused on understanding the coherence losses incurred by bottom-retained signals due to three mechanisms: sub-bottom roughness, random inhomogeneities in the sediment column, and partial reflections from near-surface layering in the sediment. Work in the first area is continuing and two as-yet-unpublished references are included here to document the status of that effort. The coupled-mode, master-equation model for spatial coherence developed by Dozier has been applied...
Topics: DTIC Archive, Spofford, C W, SCIENCE APPLICATIONS INTERNATIONAL CORP MCLEAN VA, *UNDERWATER...
A general theoretical treatment of long nonlinear wave propagation in the lower atmosphere is presented. The eigenvalue problem for finite-amplitude wave in a surface-based inversion is discussed in detail and expressions are obtained in closed form for the nonlinear wave parameters, surface perturbation pressure and wind components for a number of realistic boundary-layer waveguide models. The governing evolution equations for wave amplitude have been solved numerically for a wide variety of...
Topics: DTIC Archive, Christie,Douglas R, AUSTRALIAN NATIONAL UNIV CANBERRA RESEARCH SCHOOL OF EARTH...
This thesis presents a detailed interpretation of published theory of nonlinear optical phase conjugation by degenerate four wave mixing and by the photorefractive effect. Photorefractive phase conjugation is shown to be a low incident intensity alternative to degenerate four wave mixing (which requires high intensity incident light to achieve the nonlinear polarization of a medium. The derivations of two models for the photorefractive effect, Feinberg's Hopping Model and Kukhtarev's Solid...
Topics: DTIC Archive, Marciniak, Michael A, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF...
The image of a uniform wall illuminated by a spot light often gives a strong impression of the illuminant color. How can it be possible to know if it is a white wall illuminated by yellow light or a yellow wall illuminated by white light? If the wall is a Lambertian reflector, it would not be possible to tell the difference. However, in the real world, some amount of specular reflection is almost always present. In this memo, it is shown that the computation is possible in most practical cases....
Topics: DTIC Archive, Lee, Hsien-Che, MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB,...
Atomic ions which are stored in electromagnetic fields are an example of nonneutral plasmas. Laser techniques allow control of plasma angular momentum and provide plasma cooling to temperatures much less than 1K. Using imaging techniques, plasma spatial information is achieved. Laser spectroscopic techniques allow measurement of plasma velocity distribution functions. Liquid and solid behavior of ion plasmas is studied. Keywords: Liquid plasmas; Solid plasmas; Plasma distribution functions;...
Topics: DTIC Archive, Wineland, D J, NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO, *THERMAL...
The Burgers equation with a small viscosity term, initial and periodic boundary conditions is resolved numerically using a spatial approximation constructed from an orthonormal basis of wavelets. The algorithm is directly derived from the notions of multiresolution analysis and tree algorithms. Before the numerical algorithm is described these notions are first recalled. The methods uses extensively the localization properties of the wavelets in the physical and Fourier spaces. Moreover, we...
Topics: DTIC Archive, Liandrat, J, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON...
In speckle holography, short exposures frames along with wave front measurements allow post processing image reconstruction. With speckle holography the amplitude of high spatial frequencies is boosted to allow resolution out to the diffraction limit of the telescope. To provide system parameters for the wave front sensor design, a software analysis program has been developed that provides the system transfer function as a function of the number and size of sensor subapertures and sensor noise....
Topics: DTIC Archive, VonNiederhausern, Rudolf N, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF...
This report summarizes the research activities carried out in the Electromagnetics and Microwave Laboratory, Department of Electrical Engineering, Texas A&M University. The project was sponsored by the U.S. Army Research Office under contract No. DAAL03-92-G-0326. The topics of investigation included integrated and active antenna elements, spatial power combining and beam steering, quasioptical components, novel uniplanar slotline and coplanar waveguide circuits, and other circuit...
Topics: DTIC Archive, Chang, Kai, TEXAS A AND M UNIV COLLEGE STATION DEPT OF ELECTRICAL ENGINEERING,...
A novel algorithmic method presented for simulating complex fluids, for instance multiphase single component fluids and molecular systems. The algorithm falls under a class of single-instruction multiple-data computation known as lattice-gases, and therefore inherits exact computability on a discrete spacetime lattice. Our contribution is the use of nonlocal interactions that allow us to model a richer set of physical dynamics, such as crystallization processes, yet to do so in a way that...
Topics: DTIC Archive, Yepez, Jeffrey, PHILLIPS LAB HANSCOM AFB MA, *PARALLEL PROCESSING, *MOLECULE MOLECULE...
The littoral zone and inner continental shelf represent gateways through which continentally-derived sediment must pass on their journey to the sea. However, our knowledge of sedimentary processes and their spatial and temporal variability in these dynamic environments remains limited because of difficulties working in near shore environments and inadequate shallow water sonar technology. Improved geophysical imaging of the preserved stratigraphy in shallow water regions is critical to...
Topics: DTIC Archive, Driscoll, Neal W., WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *SHALLOW WATER,...
A modulation technique for increasing the reliable data rate achievable by an underwater acoustic communication system is presented and demonstrated. The technique, termed spatial modulation, seeks to control the spatial distribution of signal energy such that multiple parallel communication channels are supported by the single, physical ocean channel. Results from several experiments successfully demonstrate higher obtainable data rates and power throughput. Given a signal energy constraint, a...
Topics: DTIC Archive, Kilfoyle, Daniel B, WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *ACOUSTIC...
The art of camouflage pattern generation has been based on heuristic techniques, combining both art and science. The difficulty with these techniques are that pattern must perform well in a variety of different background types and conditions. To develop a camouflage that performs well over a range of backgrounds and conditions one would like a computer technique capable of optimising a camouflage pattern over all these possible combinations. The first step in developing such a system is to be...
Topics: DTIC Archive, Thomas, David J, ARMY TANK-AUTOMOTIVE COMMAND WARREN MI, *THERMAL PROPERTIES,...
This work presents a novel mechanism to generate lift towards application in micro air vehicles (MAV). Characteristics of time-mean microvortices under a range of conditions were studied via in-plane oscillation of a flat plate with and without suitable micro-structure on the plate's top surface. Methodologically, experimental approach is first commenced followed by computation to study a wide range of parameter space. The microdevice leverages on Lorentz force to drive the suspended MEMS-based...
Topics: DTIC Archive, NATIONAL TAIWAN UNIV TAIPEI, *AIRCRAFT, *FLUID MECHANICS, *LIFT, *VORTICES,...
Estimation of the three-dimensional (3-D) distribution of hydrologic properties and related uncertainty is a key for improved predictions of hydrologic processes in the subsurface. However it is difficult to gain high-quality and high-density hydrologic information from the subsurface. In this regard a promising strategy is to use high resolution geophysical data (that are relatively sensitive to variations of a hydrologic parameter of interest) to supplement direct hydrologic information from...
Topics: DTIC Archive, BOISE STATE UNIV ID CENTER FOR THE GEOPHYSICAL INVESTIGATION OF THE SHALLOW...
Propagation studies of a growing number of infrasound observations indicate that fine-scale atmospheric inhomogeneities contribute to infrasonic arrivals that are not predicted by standard modeling techniques. In particular, gravity waves, or buoyancy waves, are believed to contribute to the multipath nature of infrasound propagation and to cause penetration of infrasound into the classical shadow zones that are predicted by conventional modeling techniques. Propagation modeling studies using...
Topics: DTIC Archive, BBN TECHNOLOGIES CAMBRIDGE MA, *GRAVITATIONAL FIELDS, *INFRASOUND, ALTITUDE,...
The objective of this study is to investigate vascular oxygen dynamics in breast tumors by correlating the results of NIRS and of the BOLD method. In the research, we wish to utilize the NIR technique for a better understanding of the BOLD method in order to improve its clinical use as a diagnostic and/or prognostic tool for breast cancer research and clinical practice. We have proposed two hypotheses and three aims, as follows: Hypothesis 1: Three-channel NIRS combined with a fiber optical...
Topics: DTIC Archive, TEXAS UNIV AT ARLINGTON, *BREAST CANCER, *NEOPLASMS, *THERAPY, CARDIOVASCULAR SYSTEM,...
We quantify both the spatial and temporal variability of column integrated O3, NO2, CO, SO2, and HCHO over the Baltimore / Washington, DC area using output from the Weather Research and Forecasting model with on-line chemistry (WRF/Chem) for the entire month of July 2011, coinciding with the first deployment of the NASA Earth Venture program mission Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ). Using structure...
Topics: NASA Technical Reports Server (NTRS), POLLUTION MONITORING, SYNCHRONOUS SATELLITES, ATMOSPHERIC...
This is a continuation of a project with Dr. W. D. Gardner and Dr. M. J. Richardson at Texas A&M University. Our long-term goals are 1) to determine how changes in particle size distribution, composition and concentration on the shelf affect inherent optical properties (attenuation, absorption and scattering) and 2) correlate these measurements with hydrographic measurements (including wave and current shear stress as measured by others) to determine the forcing functions and biological...
Topics: DTIC Archive, OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES, *MIXING,...
Spatial data mining is a process to discover interesting and potentially useful spatial patterns embedded in spatial databases. Efficient tools for extracting information from spatial data sets can be of importance to organizations which own, generate and manage large geo-spatial data sets. The current approach towards solving spatial data mining problems is to use classical data mining tools after materializing spatial relationships and assuming independence between different data points....
Topics: DTIC Archive, Chawla,Sanjay, MINNESOTA UNIV MINNEAPOLIS MINNEAPOLIS United States, data mining,...
To optimize weight and cost of fire protection for aluminum ships, it is essential to know the characteristics of the fire threat. Since fire behavior is a function of fuel and environment--particularly of ventilation, fire characteristics are studied as a function of typical conditions aboard Navy ships. This report deals with various ventilation conditions. Fire characteristics such as burning rate, fuel consumed, temporal and spatial heating patterns, and O2, CO2, and CO concentrations at...
Topics: DTIC Archive, Alger,R S, NAVAL SURFACE WEAPONS CENTER WHITE OAK LAB SILVER SPRING MD, *COMBUSTION,...
An excimer laser was purchased to perform in-situ measurements of acetylene in fuel-rich flames. The acetylene measurements were performed by fragmenting acetylene with the intense 193 nm wavelength laser output and then detecting the fluorescence from CH and C2 fragments that were formed in excited states. The measurements were compared with mass spectrometer measurements and were shown to agree spatially. The data were used to determine where a soot model accurately predicted the spatial...
Topics: DTIC Archive, Pfefferle, Lisa, YALE UNIV NEW HAVEN CT DEPT OF CHEMICAL ENGINEERING, *SOOT, *LASER...
This document presents a comprehensive technical summary of the most significant work accomplished on Air Force Office of Scientific Research Contract Number F49620-99-l-0342. Since closed loop wave front control (WFC) systems currently being developed by the Air Force have residual wave front errors that reduce image quality, New Mexico State University has developed methods to reduce those residual errors and improve the quality (Strehl ratio) of Air Force WFC systems. Our approach is to...
Topics: DTIC Archive, Giles, Michael K, NEW MEXICO STATE UNIV LAS CRUCES, *LIQUID CRYSTAL DISPLAY SYSTEMS,...
An ABA triblock conjugated copolymer, poly(2,5-benzoxazole)-block-poly(benzobisthiazole-1,4-phenylene)-block-poly(2,5-benzoxazole), 1, was synthesized, characterized, and used to demonstrate spatial confinement effects on the electronic structure and the optical and optoelectronic properties of block copolymers. Optical absorption, photoluminescence, and photoluminescence excitation spectra of thin films of the triblock copolymer evidence spatial confinement of excitons as well as microphase...
Topics: DTIC Archive, Chen, X. L., ROCHESTER UNIV NY DEPT OF CHEMICAL ENGINEERING, *ELECTRONICS, *SPATIAL...
The visual system must perform two major functions. The first is resolving spatial layout, and the second is object recognition. Because we live in a three-dimensional (3D) world, these tasks must be performed in three dimensions. That is, the visual system must assess 3D spatial layout and must recognize 3D objects. There are two types of information sources that could be used to perform both functions. Cues of the first type arise directly from characteristics of in the environment. These...
Topics: DTIC Archive, Cobo-Lewis, Alan B., WISCONSIN UNIV-MADISON, *SPATIAL DISTRIBUTION, *THREE...
Surveys were conducted in 1995, 1996, and 1997 to assess community characteristics, population demography of dominant species, status of endangered species, and characteristics of nonindigenous populations of freshwater bivalves in the lower Ohio River. Data will be used to analyze impacts of construction and operation of a new lock and dam at River Mile (RM) 964.4. The greatest focus has been on a mussel bed just downstream of the project. Density categories of <20, 20 to 50, and...
Topics: DTIC Archive, Payne, Barry S., ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS, *SPATIAL...
Presented is a study of the effects of chamber background pressure on the ion axial velocity distribution within the discharge chamber and in the near-field of the Busek BHT-HD-600 xenon Hall effect thruster. Ion velocity distributions were measured along the acceleration channel centerline using laser-induced fluorescence of the 5d[4](sub 7/2)-6p[3](sub 5/2) xenon ion excited state transition. Measurements were taken at the lowest possible chamber background pressure and a pressure that was a...
Topics: DTIC Archive, Nakles, Michael R, AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE,...
Computational Fluid Dynamics (CFD) has enormous potential to impact the analysis, design, and optimization of U.S. Air Force flight systems. The objective of our work is to develop and demonstrate methods for the reliable and automatic control of discretization error in CFD. Our approach will provide designers and analysts with techniques to quantify and reduce discretization error in CFD predictions without the overhead of creating, and solving on, multiple meshes. Our work will lead to...
Topics: DTIC Archive, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG, *AERODYNAMIC LOADING,...
LONG-TERM GOAL. The long-term goal is to understand the spatial and temporal variation of the surface fluxes in relation to the variability of the sea state and the stratocumulus-topped boundary layers. OBJECTIVES. The objective of this project is to quantify the spatial and temporal variability of the turbulent fluxes in the Monterey Bay area. The analysis from this study provides the surface forcing to our collaborators (AOSN investigators) and enable us to understand these variabilities in...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF METEOROLOGY, *BOUNDARY LAYER, *COASTAL...
Results of theoretical and experimental research on resonant tunneling diodes are reported. Of particular interest were the effects of restriction of the lateral dimensions of the device to achieve quantum confinement of electrons in all three dimensions. The theoretical efforts within this program were devoted to applying a quantum-transport approach to understanding the behavior of the resonant-tunneling diode. When this program began, there had been no demonstration of total spatial...
Topics: DTIC Archive, Bate, R T, TEXAS INSTRUMENTS INC DALLAS, *DIODES, *GALLIUM ARSENIDES, *QUANTUM...
We report here on work employing tunable diode laser absorption spectrosccpy to characterize premixed, low pressure flames inhibited with halons and halon alternative agents. This characterization is in the form of spatial temperature and species concentration profiles of the flames. We report here the observation of 11 combustion species, including short lived intermediates CF2O and CF3 radical.
Topics: DTIC Archive, Daniel, R. G., ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, *LASER APPLICATIONS,...
The study of the dispersive wave equation is fundamental to an understanding of the process of geostrophic adjustment. In this report, the effect of replacing the spatial derivatives in a dispersive wave equation with second order, centered finite differences is examined with the use of Fourier Transform methods. The discretization is shown to both decrease the rate of spatial decay of the steady state solution, and to introduce additional transients at least as persistent as those in the...
Topics: DTIC Archive, Schoenstadt, Arthur L, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *FINITE DIFFERENCE...
Sets of mean monthly reference atmospheres that describe seasonal changes in the vertical distributions of temperature, density, and pressure at altitudes up to 90 km are presented for latitudes 60 deg N and 75 deg N. Also provided are specialized atmospheric models that reflect longitudinal differences in the vertical structure of temperature and density at these latitudes. Estimates of the seasonal, day-to-day, diurnal, and spatial variations are given with special emphasis placed on density....
Topics: DTIC Archive, Cole,Allen E, AIR FORCE GEOPHYSICS LAB HANSCOM AFB MASS, *ATMOSPHERE MODELS, *ARCTIC...
The methodology required to synthesize, program and validate the infrared signatures of Army aircraft (notably helicopters) and simulate their interaction with reticled sensors in a computer model to obtain sensor signal to noise ratios and error signals for arbitrary mission and flight profiles is described. The signatures account for exhaust plume emission (including effects of turbine operation and rotor down wash), hot metal parts, directional emittance due to body surface temperature (via...
Topics: DTIC Archive, Higby,R F, WESTINGHOUSE DEFENSE AND ELECTRONIC SYSTEMS CENTER BALTIMORE MD SYSTEMS...
The construction of TEAL (Transversely Excited Atmospheric pressure Laser) is described with reference to the required specification for single pulse thermal blooming experiments. All the major performance parameters are described, such as energy, temporal profile, spectrum and stability. In particular, several different measurements of the spatial profile are compared with theoretical predictions, which in general predict well the main features but not the finer details. Also the results of...
Topics: DTIC Archive, Eggins,P L, ATOMIC WEAPONS RESEARCH ESTABLISHMENT ALDERMASTON (ENGLAND), *TEA LASERS,...
