| Photophysics of C60 Colloids |
28 Nov 2012 |
188 pages |
| Authors:
Andrew F Clements; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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 | The goal of this dissertation is to study the photophysics of suspensions of colloidal C60 particles to determine if their nonlinear optical (NLO) response is superior in any way to benchmark NLO materials such as molecular solutions of C60 and carbon black suspensions (CBS). C60 in molecular form is known to exhibit strong reverse saturable absorption (RSA) and it is posited that colloidal particles composed of many C60 molecules would ... |
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| Photophysics of C60 Colloids |
28 Nov 2012 |
116 pages |
| Authors:
Andrew F Clements; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| Outline: Intro to C60 Colloids, Desired NLO Response, Overview of Nonlinear Scattering and Absorption, Previous Scholarship/Context, Thesis Question, Overview of Research, Discussions of Experiments and Findings, Basic Characterization, Transient Absorption Spectroscopy, Z-Scan, Total Scattering, Computer Modeling, Conclusions. |
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| Dissolution Rate of Propellant Energetics from Nitrocellulose Matrices |
Sep 2012 |
131 pages |
| Authors:
Susan Taylor; Katerina Dontsova; Susan Bigl; Colleen Richardson; James Lever; Jonathan Pitt; John P Bradley; Marianne Walsh; Jiri Simunek; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
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| During firing, propellant residues are scattered onto the soil surface where their energetic compounds can be dissolved by precipitation. The residues, like the unfired propellants, are composed of nitrocellulose imbibed with either 2,4-DNT (single-base), nitroglycerin (NG) (double-base) or NG and nitroguanidine (NQ) (triple-base). Although nitrocellulose is insoluble, 2,4-DNT, NG, and NQ are soluble; and 2,4-DNT and NG are also toxic. Consequently, data on how quickly 2,4-DNT, NG, and NQ are ... |
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| Using Multi-Angle WorldView-2 Imagery to Determine Ocean Depth Near Oahu, Hawaii |
Sep 2012 |
117 pages |
| Authors:
Krista R Lee; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Multispectral imaging (MSI) data collected at multiple angles over shallow water provide analysts with a unique perspective of bathymetry in coastal areas. Observations taken by DigitalGlobe's WorldView-2 (WV-2) sensor acquired at 39 different view angles on 30 July 2011 were used to determine the effect of acquisition angle on derived depth. The site used for this study was on the island of Oahu, focused on Kailua Bay (on the windward ... |
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| Hydrodynamics and Marine Optics during Cold Fronts at Santa Rosa Island, Florida |
Sep 2012 |
16 pages |
| Authors:
Timothy R Keen; Robert H Stavn; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Observations of optical and hydrodynamic processes were made on the open beach on Santa Rosa Island, Florida, in March 1995. This study focuses on the passage of two cold fronts. The observations have been supplemented by a bio-optical model, a suite of hydrodynamic models to simulate coastal flows forced by waves, tides, local wind, and coastal sea level; and a geo-optical model that predicts scattering by mineral particles resuspended by ... |
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| Probe Array Correction With Strong Target Interactions |
Aug 2012 |
47 pages |
| Authors:
John Schindler; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SENSORS DIR
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| We analyze technical problems associated with using an array of probes to measure simultaneously the near fields scattered by a target to decrease collection times. Array-target coupling distorts the fields to be measured. Element mutual coupling modifies measurements. To minimize coupling, active loading at array elements with strong target interaction is analyzed numerically. Loading minimizes perturbations in the target currents. There is little advantage to using in-situ mutual impedances to ... |
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| Ultraviolet Surface-Enhanced Rama Scattering for Detection Applications |
Aug 2012 |
26 pages |
| Authors:
Erik D Emmons; Jason A Guicheteau; III Fountain Augustus W; ARMY EDGEWOOD CHEMICAL BIOLOGICAL CENTER APG MD
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| Surface-enhanced resonance Raman scattering with UV excitation has the potential advantage of combining surface and molecular-resonance enhancements for a wide variety of analytes of interest. Nanostructured surfaces of Pd and Pt were formed by electroless deposition on germanium substrates. Ultrathin layers of Al were made by coating thick layers of Al on a microscope slide and partially dissolving them with hydrochloric acid. The substrates were assessed for their ability to ... |
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| Suppression of Stimulated Brillouin Scattering in Optical Fibers Using a Linearly Chirped Diode Laser |
02 Jul 2012 |
11 pages |
| Authors:
J O White; A Vasilyev; J P Cahill; N Satyan; O Okusaga; G Rakuljic; C E Mungan; A Yariv; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| The output of high power fiber amplifiers is typically limited by stimulated Brillouin scattering (SBS). An analysis of SBS with a chirped pump laser indicates that a chirp of 2.5 x 10 to the 15th power Hz/s could raise, by an order of magnitude, the SBS threshold of a 20-m fiber. A diode laser with a constant output power and a linear chirp of 5 x 10 to the 15th ... |
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| Wave Field Characterization Using Dual-Polarized Pulse-Doppler X-Band Radar |
Jun 2012 |
40 pages |
| Authors:
Erin E Hackett; Anne M Fullerton; Craig F Merrill; Thomas C Fu; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
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| Use of radar as a remote sensing technique for measurement of ocean surface waves presents many advantages over conventional point sensors, such as wave buoys or wave gauges. One such advantage is the ability to obtain phase-resolved wave field measurements over vast areas and at locations far from the sensor. As the use of radar for wave measurements becomes more widespread, it is important to understand the dependence and sensitivity ... |
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| The Focusing of Light Scattered from Diffuse Reflectors Using Phase Modulation |
22 Mar 2012 |
78 pages |
| Authors:
Jessica Schafer; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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| Indirect photography was recently demonstrated for imaging hidden scene information through the collection and radiometric modeling of light reflecting off of visible reflecting surfaces. The ability to focus the beam that reflects off the visible surface to a tight spot on the hidden object is theorized to simulate a direct line of sight from the light source to the object, reducing the radiometric model to that of the previously demonstrated ... |
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| Electrical and Optical Characterization of Si-Ge-Sn |
Mar 2012 |
82 pages |
| Authors:
Merle D Hamilton; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
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| The electrical characterization of boron-doped p-Si0.08Ge0.90Sn0.02/p-Ge(100) and p-Si0.112Ge0.86Sn0.028/n- Si(100) with various epilayer thicknesses was measured using the Hall effect. The room temperature sheet carrier concentration ranged from /sq cm. The room temperature mobilities were measured to be between 166 and 717 sq cm/V's, depending on sample composition. In the low temperature regime, the mobility was mainly affected by ionized impurity scattering. In the high temperature regime, the mobility was mainly ... |
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| Development of a Radar-Frequency Metamaterial Measurement and Characterization Apparatus |
Mar 2012 |
215 pages |
| Authors:
Stephen I Faris; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| The overall purpose of this research was to design, build, and test an apparatus for the measurement and characterization of radar-frequency metamaterial performance in the S-band through Ku-band (2-18 GHz). Measurement and characterization is vital to metamaterial taxonomy and ultimately vital to metamaterial definitions. Thus, the current lack of clarity in metamaterial definitions has served as the primary motivation for pursuing a method for taxonomy and thus, this apparatus. The ... |
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| Angular Distribution of Ly(alpha) Resonant Photons Emergent from Optically Thick Medium |
26 Feb 2012 |
25 pages |
| Authors:
Yang Yang; Ishani Roy; Chi-Wang Shu; Li-Zhi Fang; BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
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| We investigate the angular distribution of Ly(alpha) photons transferring in or emergent from an optically thick medium. Since the evolutions of specific intensity I in the frequency space and the angular space are coupled from each other, we first develop the WENO numerical solver in order to find the time-dependent solutions of the integro-differential equation of I in the space of frequency and angular simultaneously. We show first that the ... |
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| Three-dimensional Crack Depth Profile Assessment using Near-Field Surface Acoustic Wave Signal Response (Postprint) |
Feb 2012 |
6 pages |
| Authors:
James L Blackshire; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS & MANUFACTURING DIR METALS CERAMICS & NONDESTRUCTIVE EVALUATION DIV/NONDESTRUCTIVE EVALUATION BRANCH
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| A method for determining the three-dimensional depth profile of a surface-breaking crack-like feature is presented based on near-field surface acoustic wave signal responses. Three-dimensional finite element models were used to study the forward problem, where the characteristic near-field scattering of a surface acoustic wave incident on a surface breaking crack was investigated. Experimental validation of the modeling predictions was accomplished using a wedge transducer for surface wave generation and a ... |
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| A Multi-Scale Structural Health Monitoring Approach for Damage Detection, Diagnosis and Prognosis in Aerospace Structures |
20 Jan 2012 |
30 pages |
| Authors:
Jennifer E Michaels; Laurence J Jacobs; Massimo Ruzzene; GEORGIA TECH RESEARCH INST ATLANTA
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| This project has developed multi-scale methods for structural health monitoring to better understand, analyze and quantify the progression of damage at multiple length scales. Benchmark experiments were performed to relate nonlinearity measured with ultrasonic Lamb waves to plastic strain and fatigue life. Theory was developed and validated to predict second harmonic generation for specific mode/frequency pairs. A suite of advanced imaging methods was developed and demonstrated for detecting, locating and ... |
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| Anomalous Photon-Assisted Tunneling in Graphene |
Jan 2012 |
10 pages |
| Authors:
Andrii Iurov; Godfrey Gumbs; Oleksiy; Roslyak; Danhong Huang; AIR FORCE RESEARCH LAB KIRTLAND AFB NM
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| We investigated the transmission of Dirac electrons through a potential barrier in the presence of circularly polarized light. An anomalous photon-assisted enhanced transmission is predicted and explained. It is demonstrated that the perfect transmission for nearly head-on collision in infinite graphene is suppressed in gapped dressed states of electrons, which is further accompanied by a shift of peaks as a function of the incident angle away from head-on collision. In ... |
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| Performance Limits of Non-Line-of-Sight UV Communications |
Jan 2012 |
13 pages |
| Authors:
Gang Chen; Zhengyuan Xu; CALIFORNIA UNIV REGENTS RIVERSIDE
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| This is the interim progress peport of agreement number: W911NF-09-1-0293. Research topic is Performance Limits of Non-Line-of-Sight Optical Communications. Report Period is August 2011 to January 2012. During this report period, the following have been achieved: 1. Developed a long distance UV channel test bed. 2. Proposed a Neighbor Discovery Protocol for UV network. |
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| Realization of State-Space Models for Wave Propagation Simulations |
Jan 2012 |
17 pages |
| Authors:
Stephen A Ketcham; Minh Q Phan; Richard S Darling; Mihan H McKenna; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
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| Fully three-dimensional numerical solutions can quantify exterior seismic or acoustic propagation throughout complex geologic or atmospheric domains. Results from impulsive sources typically reveal propagating waves plus reverberations typical of multi-path scattering and wave-guide behavior, with decay toward quiescent motions as the dominant wave energy moves out of the domain. Because such computations are expensive and yield large data sets, it is advantageous to make the data reusable and reducible for ... |
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| Development of a Vision-Based Particle Tracking Velocimetry Method and Post-Processing of Scattered Velocity Data |
Jan 2012 |
72 pages |
| Authors:
Micah P Paul; WASHINGTON UNIV SEATTLE
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| In this thesis, a new vision-based hybrid particle tracking velocimetry (VB-PTV) technique is described and methods of processing randomly scattered velocity data investigated. The VB-PTV technique uses a feature matching method from computer vision theory which relies on the principles of proximity, similarity, and exclusion, meaning that it seeks to match one feature to one feature in subsequent images, and it favors matches which are close to one another and ... |
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| Integrated Modeling and Analysis of Physical Oceanographic and Acoustic Processes |
Jan 2012 |
15 pages |
| Authors:
Timothy F Duda; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The overarching long-term goal is to improve ocean physical state and acoustic state predictive capabilities. The goal fitting the scope of this project is the creation of broadly applicable and portable acoustic prediction capabilities that include the effects of internal and surface gravity waves, in addition to effects from larger scale features, with an emphasis on continental shelf and slope regions. |
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| Acoustic Coherent Backscatter Enhancement from Aggregations of Marine Animals |
Jan 2012 |
8 pages |
| Authors:
David R Dowling; MICHIGAN UNIV ANN ARBOR DEPT OF MECHANICAL ENGINEERING
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| The overall long-term goal for this project is to determine if and how acoustic coherent backscatter enhancement (ACBE) can be used for classification of active sonar returns in a wide variety of ocean environments. During its first twenty months, this project has focused on simulations of acoustic multiple scattering from aggregations of omni-directional point scatterers to determine the parametric realms in which ACBE might be observed, and its characteristics when ... |
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| Statistical Characterization and Classification of Fish School Clutter |
03 Nov 2011 |
10 pages |
| Authors:
Timothy K Stanton; Dezhang Chu; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| The goal of this study is To significantly reduce the probability of false alarm in Navy active sonar systems. This goal will be achieved through developing signal processing algorithms for active sonar systems which can account for the non-Rayleigh nature of clutter from fish schools. Part of this goal will involve characterizing the performance of the algorithm. The objectives are to develop and apply probability density functions (PDF's) to describe ... |
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| Lamb Wave Propagation in a Restricted Geometry Composite PI-Joint Specimen (Preprint) |
Nov 2011 |
10 pages |
| Authors:
James L Blackshire; Som Soni; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| The propagation of elastic waves in a material can involve a number of complex physical phenomena, resulting in both subtle and dramatic effects on detected signal content. In recent years, the use of advanced methods for characterizing and imaging elastic wave propagation and scattering processes has increased, where for example the use of scanning laser vibrometry and advanced computational models have been used very effectively to identify propagating modes, scattering ... |
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| Experimental Verification of Three-Dimensional Plasmonic Cloaking in Free-Space |
Nov 2011 |
15 pages |
| Authors:
D Rainwater; A Kerkhoff; K Melin; J C Soric; G Moreno; TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS
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| We report the experimental verification of metamaterial cloaking for a 3D object in free space. We apply the plasmonic cloaking technique, based on scattering cancellation, to suppress microwave scattering from a finite-length dielectric cylinder. We verify that scattering suppression is obtained all around the object in the near- and far-field and for different incidence angles, validating our measurements with analytical results and full-wave simulations. Our nearfield and far-field measurements confirm ... |
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| Photonic Crystals on the Wing |
Nov 2011 |
14 pages |
| Authors:
Doekele G Stavenga; GRONINGEN RIJKSUNIVERSITEIT (NETHERLANDS)
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| In the last three years, two research groups, from the universities in Groningen, the Netherlands, and Exeter, UK, working on the natural photonics of animals, have been able to join forces thanks to the EOARD/AFOSR grant. The aim of the research project has been (and is) the elucidation of the optical mechanisms involved in animal coloration. Indeed, color is one of the important aspects that characterize an animal. As will ... |
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| Phase History Decomposition for efficient Scatterer Classification in SAR Imagery |
15 Sep 2011 |
194 pages |
| Authors:
Dane F Fuller; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| A new theory and algorithm for scatterer classification in SAR imagery is presented. The automated classification process is operationally efficient compared to existing image segmentation methods requiring human supervision. The algorithm reconstructs coarse resolution subimages from subdomains of the SAR phase history. It analyzes local peaks in the subimages to determine locations and geometric shapes of scatterers in the scene. Scatterer locations are indicated by the presence of a stable ... |
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| Positive Vibrational Entropy of Chemical Ordering in FeV |
08 Sep 2011 |
5 pages |
| Authors:
J A Munoz; M S Lucas; O Delaire; M L Winterrose; L Mauger; Chen W Li; A O Sheets; M B Stone; D L Abernathy; Yuming Xiao; CALIFORNIA INST OF TECHNOLOGY PASADENA W M KECK LAB
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| Inelastic neutron scattering and nuclear resonant inelastic x-ray scattering were used to measure phonon spectra of FeVas a B2 ordered compound and as a bcc solid solution. The two data sets were combined to give an accurate phonon density of states, and the phonon partial densities of states for V and Fe atoms. Contrary to the behavior of ordering alloys studied to date, the phonons in the B2 ordered phase ... |
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| Design Considerations for Nonlinear Scattering |
Sep 2011 |
16 pages |
| Authors:
Christian Fazi; Frank Crowne; Marc Ressler; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| Renewed interest in harmonic and multitone radar has motivated design efforts based on the standard approach found in the radar literature, i.e., the classical radar equation. In this report, we show that such approaches can be problematic in determining the correct power budget requirements for detecting a nonlinear target, and that it is necessary to examine the differences of a linear versus nonlinear target cross-section. |
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| Full-wave Characterization of Rough Terrain Surface Effects for Forward-looking Radar Applications: A Scattering and Imaging Study from the Electromagnetic Perspective |
Sep 2011 |
48 pages |
| Authors:
DaHan Liao; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| The performance of ultra-wideband (UWB) radar systems suffers from reflections between frontend components caused by impedance mismatch. The Synchronous Impulse Reconstruction (SIRE) radar built by the U.S. Army Research Laboratory (ARL) is no exception. While most of the radio frequency (RF) energy in each impulse is transmitted by the radar as desired, a portion of the RF energy reflects within the radar frontend. Undesired impulse echoes arrive back at the ... |
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| Sky Glow from Cities: The Army Illumination Model v2 |
Sep 2011 |
48 pages |
| Authors:
Richard C Shirkey; ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM
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| The increasing number of people living on earth and the corresponding increase in outdoor lighting has resulted in light pollution a brightening night sky that has obliterated the stars for much of the world s population. However, for military purposes, in particular Night Vision Goggle (NVG) users, this light can allow for detection of targets that might ordinarily not be seen. The amount of light scattered from an urban location ... |
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| Reverberation, Sediment Acoustics, and Targets-in-the-Environment |
Sep 2011 |
7 pages |
| Authors:
Kevin L Williams; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
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| LONG-TERM GOALS: Develop and experimentally test target scattering models as well as reverberation/sedimentacoustic models. Quantitatively assess the modeling approximations possible within the fidelity/speed requirements of Navy performance estimators/simulators. OBJECTIVES: Over at least the last few decades, much of the basic research effort related to ASW has focused on low-frequency propagation (the passive problem). Meanwhile, submarine technology has forced the Navy to increase its use of (low and mid-frequency) active sonar, ... |
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| Mode Processing and Tomography for the Philippine Sea Experiment |
Sep 2011 |
11 pages |
| Authors:
Kathleen E Wage; GEORGE MASON UNIV FAIRFAX VA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| LONG-TERM GOALS. This project is a three-year basic research effort on deep water ocean acoustics. The broad goals of this research are to understand mode scattering in the deep water channel, to characterize deep ocean noise processes, and to implement acoustic tomography using the low mode signals. OBJECTIVES. There are three major technical objectives of the proposed research. The first objective is to analyze the spatial characteristics of noise in ... |
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| Numerical Modeling Efforts in Support of 3-D Environmental Variability and Acoustic Vector Field Studies |
Sep 2011 |
15 pages |
| Authors:
Kevin B Smith; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS
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| The goals of this work were multi-faceted, consistent with the various efforts supported by this work. One aspect was the continued study of the effects of three-dimensional (3-D) environmental variability on propagation and the flow of energy in the acoustic field. This included modeling efforts conducted at URI to support analysis of SW06 data sets in the presence of non-linear internal waves (in collaboration with Prof. Jim Miller of URI ... |
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| Propagation of Stochastic Electromagentic Fields in Atmospheric Turbulence |
31 Aug 2011 |
13 pages |
| Authors:
Olga Korotkova; MIAMI UNIV CORAL GABLES FL
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| The main topics along which the investigations under the grant were made encompassed the development of basic theory of stochastic electromagnetic fields, their free-space propagation, interaction with various media, and optical systems, their scattering from continuous media and particles, their propagation in turbulent media. In addition, deep analysis of existing and development of new techniques which utilize stochastic beams is carried out. Among our main contributions are the theory of ... |
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| Development of Optimal Strategies for Structural Health Monitoring |
25 Aug 2011 |
5 pages |
| Authors:
Fumio Kojima; KOBE UNIV (JAPAN)
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| A stochastic inverse methodology for NDT arising in electromagnetic imaging has been investigated. Two NDE applications using MCMC approach have been solved at the course of this project. One is in the identification of electromagnetic material parameters and the emphasis is on one-dimensional scattering of a dielectric slab. The other problem is a quantitative evaluation method for aging properties of cable insulation. In the sequel, the achievements for the above ... |
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| Re-addressable Interconnects with Light-Induced Waveguides in Liquid Crystals |
09 AUG 2011 |
28 pages |
| Authors:
Gaetano Assanto; ROMA TRE UNIV (ITALY) DEPT OF ELECTRONIC ENGINEERING
|
| The theoretical and numerical analyses carried out with reference to finite light beams in anisotropic dielectrics enable us to deal with narrow beams in the non-paraxial approximation, both in the linear and in the nonlinear regimes, detailing roles and contributions of the uniaxial response, the induced non-locality, the asymmetry introduced by non-negligible longitudinal field components and the second derivatives in propagation. The detailed analysis of reorientational nematic liquid crystals allows ... |
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| Metamaterial-Based Cylinders Used for Invisible Cloak Realization |
01 Aug 2011 |
94 pages |
| Authors:
Zvonimir Sipus; Dario Bojanjac; Branimir Ivsic; Tim Komljenovic; ZAGREB UNIV (CROATIA) FACULTY OF ELECTRICAL ENGINEERING AND COMPUTING
|
| The realization of structures that do not scatter electromagnetic field, i.e. structures that appear invisible for EM waves is not a new concept. The possibility of a plane wave passing through some structure without distortions (i.e. with zero scattered field) has been investigated theoretically since 1960s (see e.g. [1]-[4]). Recently, the possibility of cloaking objects using a metamaterial cover has extensively been studied ([5]-[7]). In this approach, material has been ... |
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| Aircraft Free-Space MIMO Communications |
Aug 2011 |
5 pages |
| Authors:
Michael J Gans; AIR FORCE RESEARCH LAB ROME NY
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| We investigate the use of MIMO to increase the data rate of air to air wireless links without scattered propagation. The conditions for significant improvement over SISO are outlined. |
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| Wavelet Spectral Finite Elements for Wave Propagation in Composite Plates |
31 JUL 2011 |
8 pages |
| Authors:
S. Gopalakrishnan; INDIAN INST OF SCIENCE BANGALORE DEPT OF AEROSPACE ENGINEERING
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| The principal objectives of the research were to develop and experimentally validate a predictive modeling capability for simulation of wave propagation in 2-D composite plates. During this reporting period, the Wavelet Spectral Finite Element (WSFE) model for composite plates with transverse cracks was developed. Various parametric studies were performed on the developed model to study the wave scattering behavior due to induced transverse cracks. The experimental validation of the developed ... |
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| Design of Tunable, Thin, and Wide-band Microwave Absorbers |
28 JUL 2011 |
15 pages |
| Authors:
Zhongxiang Shen; NANYANG TECHNOLOGICAL UNIV (SINGAPORE) SCHOOL OF ELECTRONIC AND ELECTRICAL ENGINEERING
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| This final report documents the research work conducted in the previous one year for the project "Design of Tunable, Thin and Wide-band Microwave Absorbers". It consists of two major parts: the first part (Section 2) is the theoretical analysis of scattering by a two-dimensional periodic array of vertical microstrip lines; the other (Section 3) is the design of a tunable microwave absorber. Simulated results are also provided to demonstrate the ... |
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| Remotely Triggered Solar Blind Signaling Using Deep Ultraviolet (UV) LEDs |
JUN 2011 |
89 pages |
| Authors:
Spencer V. Talley; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The purpose of the triggered individual identification friend or foe (IIFF) patch is to covertly reduce fratricide incidents and provide related remotely triggered marking or signaling capability. This research extended previous work by evaluating solar blind UV light emitting diodes (LEDs). Due to the zero background condition (solar blind) from 200 to 280 nm, use of a UV source in this 80 nm window can be used to create a ... |
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| Coherent Control of Thermal Transport |
10 May 2011 |
8 pages |
| Authors:
Xianfan Xu; PURDUE UNIV LAFAYETTE IN
|
| This project is to develop techniques for controlling conductive thermal transport through excitation and manipulation of coherent phonons in a material. Fundamental studies of coherent phonon generation and interactions with other energy carriers were carried out for the development of the technique. The main method employed in this project is a temporal pulse shaping technique to generate femtosecond laser pulse trains and to excite, enhance, and/or suppress coherent phonons in ... |
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| Detecting Dangerous Substances from Their 2D Spectra |
APR 2011 |
4 pages |
| Authors:
Jacob Grun; NAVAL RESEARCH LAB WASHINGTON DC
|
| Explosives, bacteria, and chemicals can be identified from their 2D resonance-Raman spectra, even when several substances are mixed together. Identification of bacteria or chemicals with Raman spectroscopy is fast, noncontact, and does not require expendable supplies. These are all desirable characteristics for many applications. The technique uses a laser to illuminate the area that may contain the suspect substance. Some of the light is absorbed by the molecule of interest ... |
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| PADF RF Localization Criteria for Multi-Model Scattering Environments |
APR 2011 |
16 pages |
| Authors:
Miguel Gates; Christopher Barber; Rastko Selmic; Huthaifa Al-Issa; Raul Ordonez; Atindra Mitra; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
|
| This paper provides a summary of recent results on a novel multi-platform RF emitter localization technique denoted as Position-Adaptive RF Direction Finding (PADF). This basic PADF formulation is based on the investigation of iterative path-loss based (i.e. path loss exponent) metrics estimates that are measured across multiple platforms in order to robotically/intelligently adapt (i.e. self-adjust) the location of each distributed/cooperative platform. Recent results at the AFRL indicate that this position-adaptive ... |
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| Synthetic Aperture Sonar Imaging of Simple Finite Targets |
15 Mar 2011 |
42 pages |
| Authors:
Steven G Kargl; Kevin L Williams; Eric I Thorsos; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| During the Sediment Acoustics Experiment 2004 (SAX04), a synthetic aperture sonar (SAS) was used to detect simple targets that were either proud or buried below a water-sediment interface, where the nominal grazing angle of incidence from the SAS to the point above a buried target was well below the critical grazing angle. SAS images from other measurements below the critical angle have also produced target detections of buried spheres and ... |
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| Epithelial and Stromal Spectral Imaging for Rapid Surgical Margin Analysis |
MAR 2011 |
19 pages |
| Authors:
Ashley Laughney; TRUSTEES OF DARTMOUTH COLL HANOVER NH OFFICE OF SPONSORED PROJECTS
|
| A broadband spectroscopy platform was developed to image thick tissue samples at a resolution sensitive to the diagnostic gold standard, pathology. Tissue samples were imaged in a 1cm2 field of view across a static beam using a motorized stage, permitting wide-field optical characterization of diagnostic pathology. The sampling spot size confined the volume of tissue probed to within a few transport pathlengths so that multiple-scattering effects were minimized and simple ... |
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| Computational Electromagnetics |
20 Feb 2011 |
9 pages |
| Authors:
Oscar P Bruno; CALIFORNIA INST OF TECH PASADENA
|
| The overall work in the proposed areas for the duration of this effort, through November 2010, is detailed in what follows. In particular, our efforts gave rise to 1) Volumetric propagation and scattering solvers for propagation through thousand of kilometers of realistic three-dimensional atmospheres (completed in 2009); 2) Development of high-order solvers, which do not suffer from restrictive CFL conditions, for solution of time-dependent wave-propagation problems in inhomogeneous media; 3) ... |
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| Wide Area Detection and Identification of Underwater UXO Using Structural Acoustic Sensors |
FEB 2011 |
86 pages |
| Authors:
J. A. Bucaro; B. H. Houston; H. Simpson; D. Calvo; L. Kraus; T. Yoder; M. Saniga; S. Dey; A. Sarkissian; DEPUTY DIRECTOR OF DEFENSE RESEARCH AND ENGINEERING ARLINGTON VA STRATEGIC ENVIRONMENTAL RESEARCH AND DEVELOPMENT PROGRAM
|
| This project explored the feasibility and advantages of applying the structural acoustic feature-based technique to the detection and identification of underwater unexploded ordnance, especially for buried targets. In the structural acoustic regime, the echoes are related to the vibrational dynamics of the object, and time-frequency features in the scattered echoes can be used to "fingerprint" and identify the target. The research focused on (1) comprehensive state-of-the-art UXO scattering measurements in ... |
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| Modeling of the Origin and Energization of the Inner Radiation Belt Electrons and Phenomena That Mediates It |
19 Jan 2011 |
22 pages |
| Authors:
Yuri Shprits; CALIFORNIA UNIV LOS ANGELES
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| We have computed scattering rates due to various plasma waves . The computed diffusion coefficients were incorporated into our 3D Versatile Electron Radiation Belts (VERB) diffusion code [Subbotin and Shprits, 2009; Shprits et al,. 2009]. We have also showed that another scattering mechanism (bounce resonance scattering) driven by magnetosonic waves plays a very important role for scattering radiation belt electrons [Shprits, 2009]. Our VERB code successfully reproduced the behavior of ... |
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| Magnetic and Vibrational Properties of High-Entropy Alloys |
Jan 2011 |
4 pages |
| Authors:
M S Lucas; L Mauger; J A Munoz; Yuming Xiao; A O Sheets; S L Semiatin; J Horwath; Z Turgut; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
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| The magnetic properties of high-entropy alloys based on equimolar FeCoCrNi were investigated using vibrating sample magnetometry to determine their usefulness in high-temperature magnetic applications. Nuclear resonant inelastic x-ray scattering measurements were performed to evaluate the vibrational entropy of the Fe atoms and to infer chemical order. The configurational and vibrational entropy of alloying are discussed as they apply to these high-entropy alloys. |
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Reports by Keyword(s)
SCATTERING
