| Graphene in NLO Devices for High Laser Energy Protection |
01 OCT 2010 |
11 pages |
| Authors:
John S. Lettow; Christy Martin; VORBECK MATERIALS CORP JESSUP MD
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 | During the last few years, graphene has emerged as a material of choice in various applications due its unique mechanical and electronic properties. Since 2005, Vorbeck Materials Corporation, presently the only company in the world that is manufacturing graphene in > ton/yr quantities suitable for industrial applications, has been working to advance the application base of graphene. We have recently demonstrated in laser protection applications, that graphene-based suspensions show non-Linear ... |
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| Impact of Input Uncertainty on Failure Prognostic Algorithms: Extending the Remaining Useful Life of Nonlinear Systems |
Oct 2010 |
8 pages |
| Authors:
Derek Edwards; Marcos E Orchard; Liang Tang; Kai Goebel; George Vachtsevanos; GEORGIA INST OF TECH ATLANTA SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING
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| This paper presents a novel set of uncertainty measures to quantify the impact of input uncertainty on nonlinear prognosis systems. A Particle Filtering-based method is also presented that uses this set of uncertainty measures to quantify, in real time, the impact of load, environmental, and other stresses for long-term prediction. Furthermore, this work shows how these measures can be used to implement a novel feedback correction loop aimed to suggest ... |
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| Improving Computational Efficiency of Prediction in Model-based Prognostics Using the Unscented Transform |
Oct 2010 |
13 pages |
| Authors:
Matthew Daigle; Kai Goebel; CALIFORNIA UNIV SANTA CRUZ
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| Model-based prognostics captures system knowledge in the form of physics-based models of components, and how they fail, in order to obtain accurate predictions of end of life (EOL). EOL is predicted based on the estimated current state distribution of a component and expected profiles of future usage. In general, this requires simulations of the component using the underlying models. In this paper, we develop a simulation-based prediction methodology that achieves ... |
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| Convection and Shear Flow in TC Development and Intensification |
30 SEP 2010 |
5 pages |
| Authors:
C. P. Chang; H. C. Kuo; C. H. Liu; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF METEOROLOGY
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| To study the dynamic processes of tropical cyclone (TC) development in the western North Pacific through field observational data and theoretical modeling. The objectives are: (1) to study the convection and vorticity generations in the vortex environment that may lead to the development and intensification of tropical cyclone; (2) to study the development and evolution of deep moist mesoscale convective system subject to strain effect due to the horizontal shear ... |
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| Particle Kalman Filtering for Ocean State Estimation |
30 SEP 2010 |
7 pages |
| Authors:
Ibrahim Hoteit; Aneesh Subramanian; Bruce Cornuelle; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
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| New nonlinear filtering algorithms were developed and are currently being tested. Numerical results suggest that nonlinear filters behave better than the ensemble Kalman filter methods with strongly nonlinear systems. They also seem to respect the dynamical of the system state more resulting in more stable predictions. |
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| Patterns of Posttraumatic Stress Symptoms, Substance Abuse, and Depression Among Deploying U.S. Marines |
30 Sep 2010 |
57 pages |
| Authors:
Valerie A Stander; Cynthia J Thomsen; NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA
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| This study explored adjustment among combat veterans in relation to the deployment cycle. In particular, it evaluated potential linear and nonlinear patterns in symptom levels in relation to both time since return home and time prior to future departure, and assessed the homogeneity of patterns of change over time across different outcomes. Personnel from U.S. Marine Corps units at three installations in Southern California completed an anonymous survey assessing a ... |
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| The Development of Methodologies for Determining Non-Linear Effects in Infrasound Sensors |
Sep 2010 |
12 pages |
| Authors:
Darren M Hart; Harold V Parks; Randy K Rembold; SANDIA NATIONAL LABS ALBUQUERQUE NM
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| The Ground-Based Nuclear Explosion Monitoring Research and Development (GNEM R&D) program at Sandia National Laboratories (SNL) is regarded as a primary center for unbiased expertise in testing and evaluation of geophysical sensors and instrumentation for nuclear explosion monitoring. Over the past year, four new infrasound sensor designs were evaluated for common performance characteristics, i.e., power consumption, response (amplitude and phase), noise, full-scale, and dynamic range. In the process of evaluating ... |
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| (DURIP 09) Ultrafast Laser System for Coherent Anti-Stokes Raman Scattering Measurements at Data Rates of 5 kHz |
22 Aug 2010 |
8 pages |
| Authors:
Robert P Lucht; PURDUE UNIV LAFAYETTE IN SCHOOL OF MECHANICAL ENGINEERING
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| Funds were requested for the purchase of an ultrafast laser system and optical parametric amplifier (OPA) for nonlinear optical diagnostics in flames at data rates of 5 kHz. The ultrafast laser system as requested in the proposal system operated at 5 kHz with a pulse energy of 1.2 mJ at the fundamental wavelength of approximately 800 nm. In the time period between the submission of the DURIP proposal and the ... |
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| A Load Shortening Curve Library for Longitudinally Stiffened Panels |
Aug 2010 |
92 pages |
| Authors:
Malcolm J Smith; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
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| Efficient methods for determining the load versus end-shortening response of longitudinally stiffened panels are considered. A library of load-shortening curves for a wide range of design parameters is developed using an automated finite element analysis (FEA) procedure. The loadshortening response of twenty benchmark stiffened panels is estimated by interpolation of the library curves. These are compared with similar curves calculated using nonlinear FEA and using design formulas published by the ... |
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| A Nonlinear Optimal Control Design using Narrowband Perturbation Feedback for Magnetostrictive Actuators |
Jul 2010 |
26 pages |
| Authors:
William S Oates; Rick Zrostlik; Scott Eichhorn; Ralph Smith; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
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| Nonlinear optimal and narrowband feedback control designs are developed and experimentally implemented on a magnetostrictive Terfenol-D actuator. The nonlinear optimal control design incorporates a nonlinear and hysteretic ferromagnetic homogenized energy model within an optimal control formulation to reduce displacement tracking errors and increase bandwidth. Improvements in robustness in the steady-state regime are achieved by utilizing narrowband feedback. A narrowband filter is implemented by treating the nonlinear and hysteretic magnetostrictive constitutive ... |
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| Organic/Organometallic Hybrids as Broadband Nonlinear Transmission Materials |
JUN 2010 |
33 pages |
| Authors:
Wenfang Sun; NORTH DAKOTA STATE UNIV FARGO
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| The ultimate goal of this project is to understand the structure-property correlation in organometallic complexes in order to develop broadband nonlinear transmission materials. To realize this goal, we have synthesized and performed systematic photophysical study and nonlinear optical characterization of 87 square-planar platinum terdentate/bidentate complexes, 5 texaphyrin derivatives, and 6 stilbazolium derivatives. In addition, we investigated the photophysics and nonlinear absorption of 10 other platinum complexes and 10 zinc phthalocyanine ... |
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| Nonlinear Structuring and High-energy Electrons: Role in Ionosphere and in Thunderstorm Atmosphere Processes |
MAY 2010 |
65 pages |
| Authors:
Aleksander V. Gurevich; RUSSIAN ACADEMY OF SCIENCES MOSCOW LEBEDEV INST
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| This report results from a contract tasking P. N. Lebedev Physical Institute as follows: The Project includes five Tasks: 1. The modification of the magnetosphere by the controllable flow of fast electrons coming upwards from the artificially modified ionosphere. Theoretical investigation and the conception of the experimental program. 2. The formation of super-narrow ionosphere structures in ionosphere artificially modified by powerful radio waves in double-resonance conditions. The super-narrow structures serve ... |
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| Manned Test and Evaluation of Morgan Breathing System 2000 (MBS 2000) Oxygen Monitoring System |
May 2010 |
13 pages |
| Authors:
D Warkander; J Chung; NAVY EXPERIMENTAL DIVING UNIT PANAMA CITY FL
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| The MBS 2000 is an O2 rebreather intended for O2 decompression use in a dry chamber. Users purge the breathing loop with O2 at preset intervals. An O2 monitoring system (OMS) may reduce the purging needs or indicate needs for more frequent purging. The OMS for the MBS 2000 consists of a sensor (R10-DN) for partial pressure of O2, but a decision on the need to purge is based on ... |
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| Intrinsic Energy Localization Through Discrete Gap Breathers in One-Dimensional Diatomic Granular Crystals |
May 2010 |
15 pages |
| Authors:
G Theocharis; N Boechler; P Kevrekidis; S Job; Mason Porter; C Daraio; CALIFORNIA INST OF TECH PASADENA
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| We study localized modes in uniform one-dimensional chains of tightly packed and uniaxially compressed elastic beads in the presence of one or two light-mass impurities. For chains composed of beads of the same type, the intrinsic nonlinearity, which is caused by the Hertzian interaction of the beads, appears not to support localized, breathing modes. Consequently, the inclusion of light-mass impurities is crucial for their appearance. By analyzing the problem's linear ... |
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| X-HALE: A Very Flexible UAV for Nonlinear Aeroelastic Tests |
Apr 2010 |
24 pages |
| Authors:
Carlos E Cesnik; Patrick J Senatore; Weihua Su; Ella M Atkins; Christopher M Shearer; Nathan A Pitcher; MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING
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| The University of Michigan has designed and is currently building an unmanned aerial vehicle, denoted X-HALE, which is aeroelastically representative of very flexible aircraft. The objective of this test bed is to collect unique data of the geometrically nonlinear aeroelastic response coupled with the flight dynamics to be used for future code validation. The aircraft will present specific aeroelastic features (e.g., coupled rigid/elastic body instability, large wing deflection during gust, ... |
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| Elastic Stress Analysis of Advanced Functionally Graded Plates Impacted by Blast Loading |
18 Jan 2010 |
38 pages |
| Authors:
Terry Hause; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| The foundation of the theory of functionally graded plates with all four edges simply supported, under a Friedlander explosive spherical air-blast, is developed, within the classical plate theory (CPT). The constituent materials, ceramic and metal, vary across the wall thickness according to a prescribed power law. The theory incorporates the geometrical nonlinearities, the dynamic effects, compressive/tensile edge loadings, damping effects, and the structural symmetries (symmetric and asymmetric). The static and ... |
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| Planning in Dynamic Environments: Extending HTNs with Nonlinear Continuous Effects |
Jan 2010 |
7 pages |
| Authors:
Matt Molineaux; Matthew Klenk; David W Aha; KNEXUS RESEARCH CORP SPRINGFIELD VA
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| Planning in dynamic continuous environments requires reasoning about nonlinear continuous effects, which previous Hierarchical Task Network (HTN) planners do not support. In this paper, we extend an existing HTN planner with a new state projection algorithm. To our knowledge, this is the first HTN planner that can reason about nonlinear continuous effects. We use a wait action to instruct this planner to consider continuous effects in a given state. We ... |
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| A Novel Method for Prediction of Nonlinear Aeroelastic Responses |
Jan 2010 |
73 pages |
| Authors:
Paul G Cizmas; Thomas W Strganac; TEXAS ENGINEERING EXPERIMENT STATION COLLEGE STATION
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| The configuration design space and flight regime of new air vehicles is vast. Determination of nonlinear aeroelastic responses, vehicle trim states and vehicle stability is a challenge that must be addressed in an efficient, methodical manner. To accomplish this, we are developing a method for determining and analyzing nonlinear aeroelastic responses using a combination of a continuation method with a variable-fidelity reduced-order model of the flowfield, a nonlinear description of ... |
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| Nonlinear Control Systems |
18 Nov 2009 |
38 pages |
| Authors:
Christopher I Byrnes; Alberto Isidori; WASHINGTON UNIV ST LOUIS MO DEPT OF ELECTRICAL AND SYSTEMS ENGINEERING
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| The principal goal of this research program was to develop a systematic methodology for the design of feedback control schemes capable of shaping the response of complex dynamical systems. A continuation of an ongoing research effort, the specific research program we proposed was aimed at the development of a systematic control methodology for lumped and distributed parameter systems, applicable to both the equilibrium and the nonequilibrium cases. The typical design ... |
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| Image Analysis Using Quantum Entropy Scale Space and Diffusion Concepts |
Nov-2009 |
44 pages |
| Authors:
Mark W Coffey; COLORADO SCHOOL OF MINES GOLDEN
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| This report documents investigations of the connections between scale space and the linear and nonlinear diffusion of images, as well as investigations of concepts of generalized entropy and quantum entropy and their measures. The generalized entropies included in particular Renyi entropy with parameter q. The diffusion studies were performed with a combination of mathematical analysis and simulations. Analysis of quantum and semi-classical entropies of modeled physical systems was also performed. ... |
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| Uncertainty Analysis and Control in Nonlinear, Multiscale, Interconnected Systems |
22 Oct 2009 |
8 pages |
| Authors:
Igor Mezic; CALIFORNIA UNIV SANTA BARBARA
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| The work under this grant continued our contribution to control of mixing in uncertainty complex environments, energy transfer in nonlinear oscillators and fundamental uncertainty theory for complex systems. Our work on control of mixing, applicable to problems of combustion in microengines, resulted in 3 publications in prominent journals. In this project we developed the theory of energy transfer that leads to synchronization in nonlinear oscillators in several directions. In [3] ... |
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| Kernel-Based Detection Techniques for Hyperspectral Imagery |
Oct 2009 |
19 pages |
| Authors:
Nasser M Nasrabadi; ARMY RESEARCH LAB ADELPHI MD
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| In this paper we implement various linear and nonlinear subspace-based anomaly detectors for hyperspectral imagery. First, a dual window technique is used to separate the local area around each pixel into two regions - an inner-window region (IWR) and an outer-window region (OWR). Pixel spectra from each region are projected onto a subspace which is defined by projection bases that can be generated in several ways. Here we use three ... |
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| Estimating the Uncertainty and Predictive Capabilities of Three-Dimensional Earth Models |
30-Sep-2009 |
11 pages |
| Authors:
Stephen C Myers; Delaine T Reiter; William L Rodi; WESTON GEOPHYSICAL LEXINGTON MA
|
| Many three-dimensional models of seismic velocity structure in Eurasia have been developed in recent years by the seismic nuclear monitoring community. Most of these models are not accompanied by quantitative estimates of uncertainty, either in the model velocities themselves or in geophysical observables predicted by the models (e.g., body-wave travel times). Moreover, the various 3D models produced by these studies have not been compared to one another for their predictive ... |
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| Mechanistic Investigations of Branched Macromolecules and Metal Nanocomposites for Nonlinear Optical Applications |
26-Sep-2009 |
29 pages |
| Authors:
Goodson; Theodore III; MICHIGAN UNIV ANN ARBOR
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| Support from the Army Research Office (ARO) has provided the opportunity for studies encompassing a combined effort consisting of different experimental and synthetic methods to produce novel nonlinear optical (NLO) materials with enhanced properties. This included the development of new synthetic branched organic macromolecules with different central core groups such as benzene, nitrogen, phosphorous, carbon as well as adamantine. These investigations gave the opportunity to probe the importance of the ... |
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| Sensor Placement for Detection of Cracks in Structures Exhibiting Nonlinear Dynamics |
09-Sep-2009 |
26 pages |
| Authors:
Matthew P Castanier; David J Gorsich; Bogdan I Epureanu; Akira Saito; Sung Kwon Hong; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| Viscoelastic Models for Nearly Incompressible Materials |
Sep-2009 |
62 pages |
| Authors:
Mike Scheidler; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| This report discusses linear and nonlinear constitutive models for the viscoelastic response of nearly incompressible solids undergoing moderate to large deformations and arbitrarily large rotations. For both the linear and nonlinear cases, the general theory is outlined first, then the Prony series approximation to the stress relaxation function is introduced, and this in turn is used to derive various incremental relations for the stress. These incremental relations can be easily ... |
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| Characteristics of the Binary Decision Diagrams of Boolean Bent Functions |
Sep-2009 |
174 pages |
| Authors:
Neil B Schafer; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Boolean bent functions have desirable cryptographic properties in that they have maximum nonlinearity, which hardens a cryptographic function against linear cryptanalysis attacks. Furthermore, bent functions are extremely rare and difficult to find. Consequently, little is known generally about the characteristics of bent functions. One method of representing Boolean functions is with a reduced ordered binary decision diagram. Binary decision diagrams (BDD) represent functions in a tree structure that can be ... |
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| Nonlinear Aspects of Internal Waves in the Atmosphere |
20 Aug 2009 |
78 pages |
| Authors:
John P McHugh; NEW HAMPSHIRE UNIV DURHAM
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| Internal waves in the atmosphere are responsible for a significant percentage of atmospheric turbulence, particularly at the tropopause. This turbulence can interfere with Air Force operations, and is in need of improved prediction methods. The research has considered a sequence of idealized phenomena aimed at this ultimate goal. The results show that nonlinear effects enhance wave amplitude at the altitude where the buoyancy frequency changes suddenly. Vertically propagating wave packets ... |
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| Adaptive Design for Sensitivity Experiments and Related Problems |
07-Aug-2009 |
3 pages |
| Authors:
C F Wu; Roshan J Vengazhiyil; GEORGIA TECH RESEARCH CORP ATLANTA
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| The main goal of this research is to develop novel methodologies in the design and modeling of sensitivity testing and related experiments, which are commonly encountered in military applications. The research has progressed well with four papers accepted and scheduled to appear, one tentatively accepted and one under review. Paper 1 proposes a new sequential procedure for root finding in highly nonlinear situations. Paper 2 addresses the modeling and data ... |
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| Moored Observations to Define the Structure and Energetics of Non-Linear Internal Wave Generation over the New Jersey Shelf |
Aug-2009 |
10 pages |
| Authors:
Jonathan D Nash; OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES
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| Non-Linear Internal Wave (NLIW) packets are ubiquitous, yet they arrive with a high degree of irregularity in coastal oceans. Through this award, three water-column moorings and four bottom landers were deployed during the New Jersey Shelf Shallow Water 2006 (SW06) experiment. These moorings span the generation region for NLIWs and have been used to (1) quantify the structure, energetics, and timing of O(100) wave packets, (2) elucidate wave formation, the ... |
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| A Non-Linear Model for Elastic Dielectric Crystals with Mobile Vacancies |
Jul-2009 |
20 pages |
| Authors:
J D Clayton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| A framework is developed for electromechanical behavior of dielectric crystalline solids subjected to finite deformations. The theory is formulated in the context of electrostatics; however, vacancies in the lattice may carry an electric charge, and their concentrations may be large. The material is treated as a continuous body with a continuous distribution of point vacancies, but volumes and charges of individual defects enter the description. The deformation gradient is decomposed ... |
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| Nonlinear Localized Dissipative Structures for Long-Time Solution of Wave Equation |
Jul-2009 |
43 pages |
| Authors:
John Steinhoff; TENNESSEE UNIV SPACE INST TULLAHOMA
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| A new numerical method, Wave Confinement (WC), is developed to efficiently solve the linear wave equation. This is similar to the originally developed Vorticity Confinement method for fluid mechanics problems. It involves modification of the discrete wave equation by adding an extra nonlinear term that can accurately propagate the pulses for long distances without numerical dispersion/diffusion. These pulses are propagated as stable codimension-one surfaces and do not suffer phase shift ... |
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| Determination of Critical Factors in Unmanned Casualty Evacuation in the Distributed Environment |
Jun-2009 |
67 pages |
| Authors:
Ralph L Featherstone; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The current battlefield is changing rapidly. Combat operations against irregular forces are set in a dispersed, non-linear battlefield. Vast distances between small units such as the infantry squad, and the distances from these small elements to their supporting organizations, pose unique challenges. Casualty evacuation is an evolving challenge. The goal of casualty evacuation is to transport an injured Marine from the point of injury to a medical care facility. Increased ... |
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| Gravitational and Magnetic Anomaly Inversion Using a Tree-Based Geometry Representation |
Jun-2009 |
24 pages |
| Authors:
George A Gazonas; Raymond A Wildman; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| Gravitational and magnetic anomaly inversion of homogeneous 2D and 3D structures is treated using a geometric parameterization that can represent multiple, arbitrary polygons or polyhedra and a local-optimization scheme based on a hill-climbing method. This geometry representation uses a tree data structure, which defines a set of Boolean operations performed on convex polygons. A variable-length list of points, whose convex hull defines a convex polygon operand, resides in each leaf ... |
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| Stability of Large-Scale Oceanic Flows and the Importance of Non-Local Effects |
Jun-2009 |
|
| Authors:
Hristina G Hristova; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
 | My thesis covers two general circulation problems that involve the stability of large scale oceanic flows and the importance of non-local effects. The first problem examines the stability of meridional boundary currents, which are found on both sides of most ocean basins because of the presence of continents. A linear stability analysis of a meridional boundary current on the beta-plane is performed using a quasi-geostrophic model in order to determine ... |
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| Nonlinearities and Wave Mixing Properties of Negative Index Materials (Nanotechnology Initiative) |
31-May-2009 |
4 pages |
| Authors:
Aref Chowdhury; LUCENT TECHNOLOGIES INC MURRAY HILL NJ
|
| The primary goal of this project was to develop new ideas in the area of nonlinearities in negative refractive index media, with particular focus on the optical regime as this is a regime that exhibits strong nonlinearities. As metamaterials are composed of sub-wavelength unit cells by their very nature, metamaterials in the optical regime are nanostructures. Thus, the research directly addressed novel nonlinear effects in nanostructured negative index metamaterials. The ... |
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| Detached-Eddy Simulation of Flow Non-Linearity of Fluid-Structural Interactions Using High Order Schemes |
May-2009 |
199 pages |
| Authors:
Gecheng Zha; Baoyuan Wang; MIAMI UNIV CORAL GABLES FL DEPT OF MECHANICAL ENGINEERING
|
| The objective of this research is to develop an efficient and accurate methodology to resolve flow non-linearity of fluid-structural interaction. To achieve this purpose, a numerical strategy to apply the detached-eddy simulation (DES) with a fully coupled fluid-structural interaction model is established for the first time. The following novel numerical algorithms are also created: a general sub-domain boundary mapping procedure for parallel computation to reduce wall clock simulation time, an ... |
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| Internally Actuated Lateral-Directional Maneuvering for a Blended Wing-Body Underwater Glider |
Apr-2009 |
22 pages |
| Authors:
Craig A Woolsey; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG OFFICE OF SPONSORED PROGRAMS
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| The principal goals of Phases I & II (the YIP Award and Supplement) were to: (1) Enhance the performance capability of streamlined AUVs by extending their operating range to include hover. (2) Develop energy-based nonlinear control design tools and demonstrate them in practical vehicle applications. (3) Develop algorithms for simple flow-field modeling and identification using data from a platoon of small AUVs. The principal goal of Phase III was to: ... |
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| A Non-Linear Finite Element Model for the Determination of Elastic and Thermal Properties of Nanocomposites |
Apr-2009 |
107 pages |
| Authors:
Paul Elsbernd; RICE UNIV HOUSTON TX
|
| This thesis presents a non-linear model for the thermal and elastic properties of single-walled carbon nanotube reinforced polymer composites. Finite Element Analysis (FEA), in conjunction with the Embedded Fiber Method (EFM), is used to calculate the effective stress-strain curve and thermal conductivity of the composite material. First, the geometry of a user-defined volume fraction of nanotubes is randomly generated and their properties are incorporated into the polymer matrix using the ... |
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| High Average Power Diode Pumped Solid State Lasers: Power Scaling With High Spectral and Spatial Coherence |
30-Mar-2009 |
97 pages |
| Authors:
Robert L Byer; J Wisdom; K Urbanek; S Sinha; A Serpry; T Plettner; Y Lee; P S Kuo; R Gaume; H Bae; R Route; M Digonnet; S Wong; STANFORD UNIV CA
|
| The main program objective was the development of a kilowatt class, cw Nd:YAG diode-laser-pumped solid-state laser (DPSSL) with quantum noise limited amplitude and phase, 24by7 operation capability and the ability to be repaired while in operation. The approach was a master-oscillator power-amplifier (MOPA) laser utilizing a series of zig-zag slab power amplifiers stages. We developed fiber amplifiers at the 200W level to generate power with high optical efficiency that can ... |
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| Q-Switched and Mode Locked Short Pulses from a Diode Pumped, YB-Doped Fiber Laser |
26-Mar-2009 |
115 pages |
| Authors:
Seth M Swift; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| A diode-pumped, ytterbium (Yb)-doped fiber laser system was designed and demonstrated to operate in continuous wave (cw), passively Q-switched and possibly passively mode locked operation. To our knowledge, this was the first fiber laser oscillator built at the Air Force Institute of Technology. A Cr4+:YAG (Chromium: Ytterbium Aluminum Garnett) crystal was used as a saturable absorber to generate Q-switched pulses. Attempts to mode lock the laser were performed using a ... |
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| Least-Squares Finite Element Formulation for Fluid-Structure Interaction |
Mar-2009 |
276 pages |
| Authors:
Cody C Rasmussen; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Fluid-structure interaction problems prove difficult due to the coupling between fluid and solid behavior. Typically, different theoretical formulations and numerical methods are used to solve fluid and structural problems separately. The least-squares finite element method is capable of accurately solving both fluid and structural problems. This capability allows for a simultaneously coupled fluid structure interaction formulation using a single variational approach to solve complex and nonlinear aeroelasticity problems. The least-squares ... |
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| A Continuum Description of Nonlinear Elasticity, Slip and Twinning, With Application to Sapphire |
Mar-2009 |
38 pages |
| Authors:
J D Clayton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| A model is developed for elasticity, plasticity and twinning in anisotropic single crystals subjected to large deformations. Dislocation glide and deformation twinning are dissipative, while energy storage mechanisms associated with dislocation lines and twin boundaries are described via scalar internal state variables. Concepts from continuum crystal plasticity are invoked, with shearing rates on discrete glide and twinning systems modelled explicitly. The model describes aspects of thermomechanical behaviour of single crystals ... |
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| An Evaluation of Growth Models as Predictive Tools for Estimates at Completion (EAC) |
Mar-2009 |
80 pages |
| Authors:
Elizabeth N Trahan; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Efficient decision making mandates the accuracy of forecasted estimations of a contract's final value known within Earned Value Management (EVM) as the Estimates at Completion (EAC). Our research evaluates the prospect of nonlinear growth modeling as an alternative to the current predictive tools used for calculating EAC, such as the Cost Performance Index (CPI), the Schedule Cost Index (SCI), and the Composite Index methods. Our study uses the Gompertz growth ... |
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| Solving for Optimal Retirement Financial Plans by Maximizing a Discounted Habit Formation Utility Function |
Mar-2009 |
55 pages |
| Authors:
Wesley P Johnson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| With the increasing popularity of defined-benefit retirement plans, retiring individuals are looking for professional financial advice to help manage their nest eggs. Commonly prescribed generic one size fits all rules of thumb such as the 4% Rule can carry someone successfully through retirement, but they do not effectively take into account individual expectations or preferences of the retiree or the volatility and risk of the capital markets. An alternative approach ... |
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| Analysis of Implicit Modeling of Complex Geometric Environments |
28-Feb-2009 |
29 pages |
| Authors:
Gregory M Nielson; ARIZONA STATE UNIV TEMPE
|
| 1. Developed methods for extracting mathematical surface description of urban/terrain implicitly defined from scattered point cloud data obtained from scanners and other detecting devices 2. Developed methods for parameterizing surfaces representing urban/terrain environments which are implicitly modeled. 3. Developed a custom software environment for simulating scanner output producing point cloud data sets. 4. Developed and analyzed adaptive, implicit mathematical methods for modeling data scanned from complex geometric environment. 5. Developed, ... |
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| An Optimization Framework Based on Domain Decomposition and Model Reduction |
27-Feb-2009 |
21 pages |
| Authors:
Matthias Heinkenschloss; Danny C Sorensen; RICE UNIV HOUSTON TX DEPT OF COMPUTATIONAL AND APPLIED MATHEMATICS
|
| This collaborative research has developed rigorous mathematical and computational frameworks for reduced order model (ROM) generation and the use of ROMs in real-time, design, control, and probabilistic applications of relevance to the Air Force. This research has provided theoretical analyses and numerical studies for several new/extensions of existing ROM approaches, such as goal-oriented, model-constrained approach, balanced truncation model reduction (BTMR) of descriptor systems, and the integration of domain decomposition and ... |
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| The Windy Island Soliton Experiment (WISE): Shallow Water and Basin Experiment Configuration and Preliminary Observations |
19-Feb-2009 |
103 pages |
| Authors:
Christopher W Miller; Marla Stone; Keith Wyckoff; Fred Bahr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The Windy Islands Soliton Experiment (WISE) was designed by Taiwan and US physical oceanographers to observe the generation, evolution and transformation of the transbasin, nonlinear internal waves in the Northeastern South China Sea for a period of one year beginning April 2005. To augment the naval relevance of WISE, specifically in the area of antisubmarine warfare, two acoustic propagation studies, one over the shallow shelf and one over the deep ... |
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| Eddy-Mean Flow Interactions in Western Boundary Current Jets |
Feb-2009 |
|
| Authors:
Stephanie N Waterman; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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| This thesis examines eddy-mean flow interactions in western boundary current jets via theoretical studies of eddy-mean flow interactions in idealized configurations and an observational analysis to characterize eddy-mean flow interactions in the Kuroshio Extension. Theoretical studies are made of the mechanism by which eddies drive recirculation gyres through nonlinear rectification, and the role that eddies play in the downstream evolution of a baroclinic jet subject to mixed instabilities. The observational ... |
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| Design and Implementation of Nonlinear Force Controllers for Friction Stir Welding Processes |
Feb-2009 |
40 pages |
| Authors:
Prabhanjana Kalya; Xin Zhao; Robert G Landers; K Krishnamurthy; MISSOURI UNIV-ROLLA
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| In Friction Stir Welding (FSW) processes, force control can be used to achieve good welding quality. This paper presents the systematic design and implementation of FSW force controllers. The axial and path forces are modeled as nonlinear functions of the FSW process parameters (i.e., plunge depth, tool traverse rate, and tool rotation speed). Equipment models, which include communication delays, are constructed to relate the commanded and measured actuator signals. Based ... |
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Reports by Keyword(s)
NONLINEAR SYSTEMS
