| On-board Model Predictive Control of a Quadrotor Helicopter: Design, Implementation, and Experiments |
13 Dec 2012 |
82 pages |
| Authors:
Patrick Bouffard; CALIFORNIA UNIV BERKELEY DEPT OF COMPUTER SCIENCES
|
 | This report describes work in applying model predictive control (MPC) techniques to the control of quadrotor helicopters, a type of micro aerial vehicle (MAV) platform that has gained great popularity in recent years both in research and commercial/military settings. MPC is a form of optimal control which is attractive in part because it allows engineering requirements to be addressed directly in the design of the controller in terms of costs ... |
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| Long-Range Acoustic Doppler Current Profilers for Internal Waves in Straits Experiment (IWISE) |
11 Dec 2012 |
15 pages |
| Authors:
Luc Rainville; Matthew H Alford; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| We are interested in the general problems of internal waves and ocean mixing. Knowledge of these is important for advancing the performance of operational and climate models, as well as for understanding local problems such as pollutant dispersal and biological productivity. In the specific case of NLIWs, the currents and displacements of the waves are strong enough to impact undersea operations. We use a combination of several existing instruments, several ... |
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| Automated Neuropsychological Assessment Metrics Version 4 (ANAM4): Select Psychometric Properties and Administration Procedures |
Dec 2012 |
63 pages |
| Authors:
Susan P Proctor; Kristin J Heaton; HENRY M JACKSON FOUNDATION FOR THE ADVANCEMENT OF MILITARY MEDICINE ROCKVILLE MD
|
| The ability to accurately and efficiently monitor the neurocognitive status of US warfighters under diverse operational and experimental conditions is of critical importance to the ongoing mission and network-centered initiatives of the United States military. The Automated Neuropsychological Assessment Metrics (ANAM) is a computer assisted tool for evaluating neurocognitive performance with demonstrated effectiveness for application in diverse military operational and research testing scenarios. The primary objective of this project is ... |
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| The Predictability of Large-Scale, Short-Period Ocean Variability in the Philippine Sea and the Influence of Such Variability on Long-Range Acoustic Propagation |
15 Oct 2012 |
14 pages |
| Authors:
Brian Dushaw; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| The long-term goal of this project is a complete and accurate understanding of the properties of acoustic pulses sent over mesoscale to global scales. In particular, I want to understand the forward problem for calculating travel times of the early ray arrivals in long-range acoustic transmissions and to understand the sampling associated with those arrivals. The better the understanding of the forward problem, the better acoustic data can be used ... |
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| Mechanism-Based Modeling of Hydrogen Environment Assisted Cracking (HEAC) in High Strength Alloys for Marine Applications: Prediction of Monel K-500 HEAC for Select Environmental and Mechanical Conditions |
15 Oct 2012 |
142 pages |
| Authors:
John R Scully; Richard P Gangloff; Francisco P Moreno; VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| The objective of this interdisciplinary research program was to implement quantitative predictive models of hydrogen environment assisted cracking (HEAC) of Monel K-500 in a pseudo-application specific situation. Here the crack growth behavior and component lifetime will be predicted as a function of applied stress, surface condition component geometry (summed into stress intensity variation), as well as metallurgical and environmental conditions (applied cathodic potential in seawater with local pH and potential ... |
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| Wave Height and Water Level Variability on Lakes Michigan and St Clair |
Oct 2012 |
183 pages |
| Authors:
Jeffrey A Melby; Norberto C Nadal-Caraballo; Yamiretsy Pagan-Albelo; Bruce Ebersole; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
|
| The Great Lakes are subject to coastal flooding as a result of severe storms. Strong winds blowing across the surface of the lakes produce high waves and surge. Variations in lake levels due to decadal scale variations in precipitation and anthropogenic activities affect the risk of flooding. In this report, historical storm climatology on Lakes Michigan and St Clair, and the resulting measured waves and water levels, are analyzed in ... |
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| Potential Natural Vegetation of the Mississippi Alluvial Valley: Boeuf-Tensas Basin, Arkansas, Field Atlas |
Sep 2012 |
127 pages |
| Authors:
Charles Klimas; Thomas Foti; Jody Pagan; Malcolm Williamson; R D Smith; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
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| Over the past three decades, extensive field studies of wetland plant communities have been conducted in the Mississippi Alluvial Valley. These field studies have been carried out for various purposes under the auspices of federal and state research programs or in conjunction with Corps of Engineers project planning efforts. In the process, a wetland site classification approach has evolved based on hydrology, soils, and geomorphic setting. The research data and ... |
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| Growth Stress in Si02 Formed by Oxidation of SiC (Preprint) |
Jul 2012 |
8 pages |
| Authors:
Randall S Hay; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Growth stresses in amorphous SiO2 scales formed during SiC fiber oxidation were calculated. A numerical method using Deal-Grove oxidation kinetics and shear-stress dependent SiO2 viscosity was used. Initial compressive stresses in SiO2 of 25 GPa from the 2.2? oxidation volume expansion rapidly relaxes. At 1200?, viscous flow of amorphous SiO2 further relaxes stress to negligible levels. At 700? - 900?C, axial and hoop stress at the GPa level persist in ... |
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| Effects of Processing and Powder Size on Microstructure and Reactivity in Arrested Reactive Milled Al + Ni |
May 2012 |
19 pages |
| Authors:
Eric B Herbold; Jennifer L Jordan; N N Thadhani; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Ball-milling Al-metal powders can result in self-sustaining high-temperature synthesis in intermetallic-forming systems. Here, Al and Ni powders with similar composition are used to investigate how microstructural differences affect the measured time to reaction (TTR) between powders of different sizes processed under milling conditions specified by statistically designed experiments. Linear statistical models predicting the TTR and the change in temperature (DT) are built from these experimental results. The time required to ... |
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| Real-time Probabilistic Covariance Tracking with Efficient Model Update |
May 2012 |
16 pages |
| Authors:
Yi Wu; Jian Cheng; Jinqiao Wang; Hanqing Lu; Jun Wang; Haibin Ling; Erik Blasch; Li Bai; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
|
| The recently proposed covariance region descriptor has been proven robust and versatile for a modest computational cost. The covariance matrix enables efficient fusion of different types of features, where the spatial and statistical properties as well as their correlation are characterized. The similarity between two covariance descriptors is measured on Riemannian manifolds. Based on the same metric, but with a probabilistic framework, we propose a novel tracking approach on Riemannian ... |
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| Images of Bottomside Irregularities Observed at Topside Altitudes (Postprint) |
04 Apr 2012 |
16 pages |
| Authors:
William J Burke; Louise C Gentile; Shannon R Shomo; Patrick A Roddy; Robert F Pfaff; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| We analyzed plasma and field measurements acquired by the Communication/ Navigation Outage Forecasting System (C/NOFS) satellite during an eight-hour period on 13 14 January 2010 when strong to moderate 250 MHz scintillation activity was observed at nearby Scintillation Network Decision Aid (SCINDA) ground stations. C/NOFS consistently detected relatively small-scale density and electric field irregularities embedded within large-scale (_100 km) structures at topside altitudes. Significant spectral power measured at the Fresnel ... |
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| Incremental Sampling Methodology (ISM). Part 1, Section 3: Systematic Planning |
Mar 2012 |
33 pages |
| Authors:
INTERSTATE TECHNOLOGY AND REGULATORY COUNCIL(ITRC) WASHINGTON DC
|
| Summary: Systematic Planning. Conduct Systematic Planning. It's important to develop a CSM before beginning a sampling design. Be sure that your sampling design will achieve your sampling objectives. Be certain that your sampling design will provide the kind of data necessary to fulfill the sampling objectives. Decision Unit designation. Make sure that all site information has been used to develop your DUs. Be sure that your scale of decision making ... |
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| Sound Generation in the Interaction of Two Isentropic Vortices |
02 Feb 2012 |
16 pages |
| Authors:
Shuhai Zhang; Hanxin Zhang; Chi-Wang Shu; BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
|
| Through direct numerical simulation (DNS) for the sound generated by the interaction between two isentropic vortices, it is found that the interaction between two vortices with a large difference in their strengths or scales can generate continuous strong noise. The interaction between two isentropic vortices results in the formation of two vortex dipoles, with each vortex dipole containing two vortex cores. If there is a large difference in their initial ... |
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| On the Renormalization of the Covariance Operators |
Feb 2012 |
14 pages |
| Authors:
Max Yaremchuk; Matthew Carrier; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| Many background error correlation (BEC) models in data assimilation are formulated in terms of a smoothing operator B, which simulates the action of the correlation matrix on a state vector normalized by respective BE variances. Under such formulation, B has to have a unit diagonal and requires appropriate renormalization by rescaling. The exact computation of the rescaling factors (diagonal elements of B) is a computationally expensive procedure, which needs an ... |
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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
|
| 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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| Simulating the Mechanical Response of Titanium Alloys Through the Crystal Plasticity Finite Element Analysis of Image-Based Synthetic Microstructures |
Jan 2012 |
103 pages |
| Authors:
Josh Thomas; OHIO STATE UNIV COLUMBUS
|
| Micromechanical crystal plasticity finite element simulations of the response of synthetic titanium microstructures are carried out with the goal of quantifying the effect of microstructure on mechanical properties. Two separate materials are studied: (1) an alpha-Beta Ti-6Al-4V material and (2) a highly-textured, rolled lpha Ti-3Al-2.5V sheet material. Performing accurate finite element analyses begins with accurate image-based characterization of the morphological and crystallographic features of the materials at the microstructural scale. ... |
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| Computational and Experimental Analysis of Mach 5 Air Flow over a Cylinder with a Nanosecond Pulse Discharge |
Jan 2012 |
31 pages |
| Authors:
Nicholas J Bisek; Jonathan Poggie; Munetake Nishihara; Igor Adamovich; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
|
| A computational study is performed for Mach 5 air flow over a cylinder with a dielectric barrier discharge actuator set into the cylinder surface. The actuator is pulsed at nanosecond time scales, which rapidly adds energy to the flow, thereby creating a shock wave that travels away from the pulse source. As the shock wave travels upstream, it interacts with the standing bow-shock and momentarily increases the bow-shock standoff distance. ... |
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| Deceleration of Projectiles in Sand |
Jan 2012 |
5 pages |
| Authors:
Stephan Bless; William Cooper; Keiko Watanabe; Robert Peden; AIR FORCE RESEARCH LAB EGLIN AFB FL
|
| Penetration of projectiles was measured for hemispherical and conical nose shapes penetrating granular media. Targets were beds of Ottawa sand and Eglin sand. Projectiles were rigid metals. Experimental parameters that were varied included velocity (from 300 to 600 m/s), nose shape, sand density, and scale (from 5 mm to 20 mm). Strong evidence for scale effects is found: 5 mm diameter projectiles are less effective penetrators than 12.5, 15, or ... |
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| Modular Electronics for Flash Memory Production |
28 Dec 2011 |
12 pages |
| Authors:
J F Stoddart; Chad A Mirkin; NORTHWESTERN UNIV EVANSTON IL DEPT OF CHEMISTRY
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| The continued reduction of the feature density of memory chips has increased interest in the utilization of molecules as the functional elements in electronic memory devices because of the advantages they offer in terms of size compared to conventional circuit elements. The development of molecular electronic devices for memory applications in computing, however, continues to be an important challenge to researchers in nanoscience and nanotechnology, both from a fundamental and ... |
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| Multi-output Local Gaussian Process Regression: Applications to Uncertainty Quantification |
07 Dec 2011 |
63 pages |
| Authors:
Ilias Bilionis; Nicholas Zabaras; CORNELL UNIV ITHACA NY MATERIALS PROCESS DESIGN AND CONTROL LABORATORY (MPDC)
|
| We develop an efficient, Bayesian Uncertainty Quantification framework us- ing a novel treed Gaussian process model. The tree is adaptively constructed using information conveyed by the observed data about the length scales of the underlying process. On each leaf of the tree, we utilize Bayesian Experimental Design techniques in order to learn a multi-output Gaussian process. The constructed surrogate can provide analytical point estimates, as well as error bars, for ... |
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| Dislocation Transport in Continuum Crystal Plasticity Simulations (First-year Report) |
Dec 2011 |
32 pages |
| Authors:
Richard Becker; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Continuity of dislocation flux across element boundaries is introduced into a non-local, explicit finite element code using a continuum crystal plasticity constitutive model. In addition to providing enhanced coupling of the deformation field among neighboring elements, dislocation fluxes are integrated through time to give an estimate of dislocation gradients that serve as a strengthening mechanism. The results demonstrate the effects of dislocation flux continuity and the realization of a size ... |
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| The Reduction of Advanced Military Aircraft Noise |
Dec 2011 |
191 pages |
| Authors:
Philip J Morris; Dennis McLaughlin; Victor Sparrow; James Bridges; Brenda Henderson; Kenneth Plotkin; Steve Martens; Richard McKinley; PENNSYLVANIA STATE UNIV STATE COLLEGE
|
| This report describes a combined experimental and computational study of the generation and radiation of jet noise from high performance military fighter aircraft. An emphasis is on the methodology for scaling measurements at small and moderate scale to full scale aircraft engines. Promising concepts for jet noise reduction are explored at small and moderate scale. Numerical simulations are performed to support the experiments and provide additional insight into the noise ... |
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| Heat Transfer Enhancement in Small-Scale Devices: A Collaborative Experimental/Numerical Approach |
28 Nov 2011 |
21 pages |
| Authors:
Gian P Beretta; Pietro Poesio; UNIVERSITA DI BRESCIA (ITALY)
|
| The aim of the project has been the analysis of spinodal decomposition of binary liquid mixtures for heat transfer enhancement in micro-devices. The work has followed two main lines and approaches: experimental investigation of heat transfer in small scale heat exchangers and numerical modeling to build a designing tool. For the first approach, the results show a significant increase of heat transfer efficiency up to 100% compared to conventional techniques, ... |
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| All-optical Integrated Switches Based on Azo-benzene Liquid Crystals on Silicon |
Nov 2011 |
16 pages |
| Authors:
Antonio d'Alessandro; UNIVERSITA DI ROMA LA SAPIENZA ROMA (ITALY)
|
| Objective of this project is the design and fabrication of optically controlled switches using LC doped with azobenzene groups, with large nonlinear optical response, embedded in SiO2/Si grooves able to operate at telecom wavelengths (1500-1600 nm). Such LC mixtures are commercially available from Beam Engineering able also to synthesize custom mixtures for research purposes. In particular some fast switching mixtures are promising to obtain photonic devices with submicrosecond time responses. ... |
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| Feasibility of Leveraging Crowd Sourcing for the Creation of a Large Scale Annotated Resource for Hindi English Code Switched Data: A Pilot Annotation |
Nov 2011 |
6 pages |
| Authors:
Mona Diab; Ankit Kamboj; COLUMBIA UNIV NEW YORK CENTER FOR COMPUTATIONAL LEARNING SYSTEMS
|
| Linguistic code switching (LCS) occurs when speakers mix multiple languages in the same speech utterance. We find LCS pervasively in bilingual communities. LCS poses a serious challenge to Natural Language and Speech Processing. With the ubiquity of informal genres online, LCS is emerging as a very widespread phenomenon. This paper presents a first attempt at collecting and annotating a large repository of LCS data. We target Hindi English (Hinglish) LCS. ... |
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| Milli-Biology |
30 Oct 2011 |
48 pages |
| Authors:
Neil Gershenfeld; MASSACHUSETTS INST OF TECH CAMBRIDGE OFFICE OF SPONSORED RESEARCH
|
| The milli-biology project was inspired by the existence proof for programmable matter, molecular biology. Macroscopic organisms are full of microscopic machinery, assembled from nanostructures. The heart of how this happens is protein folding in the ribosome, where a one-dimensional mRNA codes for the assembly of a three-dimensional functional protein by linking amino acids. Milli-biology sought to re-implement this natural workflow with engineered materials, in order to expand the range of ... |
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| Communicating Coastal Risk Analysis in an Age of Climate Change |
Oct 2011 |
6 pages |
| Authors:
Brian Blanton; John McGee; Oleg Kapeljushnik; NORTH CAROLINA UNIV AT CHAPEL HILL INST OF RENAISSANCE COMPUTING
|
| Complex science and large volumes of disparate data required for risk analysis of coastal hazards can be very difficult to communicate effectively to government and business decision makers. Including potential future scenarios as a result of climate change complicates matters further. An immersive visualization environment integrating data from high resolution imagery sensed and measured data, model output, and more, that can scale from the desktop to large dome theater venues ... |
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| Miniature and Molecularly Specific Optical Screening Technologies for Breast Cancer |
Oct 2011 |
28 pages |
| Authors:
Nirmala Ramanujam; DUKE UNIV DURHAM NC
|
| The goal of this proposal is to harness the power of light to create miniature and molecularly specific optical technologies for breast cancer diagnosis and detection. The miniature technologies will leverage on millimeter scale silicon detectors and LEDs to make compact devices that can be used in a practical clinical setting for breast cancer detection. The features that will be exploited for optical detection/diagnosis of breast cancer will include the ... |
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| Lateral Mixing DRI: Turbulence-Resolving Simulations of Upper-Ocean Lateral Mixing |
30 Sep 2011 |
6 pages |
| Authors:
Ramsey R Harcourt; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| This study contributes to our long-term efforts toward understanding: Mixed layer dynamics, processes that communicate atmospheric forcing to the ocean interior, frontal dynamics, in particular the role of surface forcing in lateral mixing, and the interaction of finescale and submesoscale upper-ocean mixing at fronts. The focus of modeling in this study is to quantify relationships between surface fluxes of heat, energy and momentum, the available baroclinic potential energy, the resultant ... |
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| Shipboard LADCP/chipod Profiling of Internal Wave Structure and Dissipation in the Luzon Strait |
30 Sep 2011 |
7 pages |
| Authors:
Jonathan D Nash; James N Moum; OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES
|
| We seek a more complete and fundamental understanding of the hierarchy of processes which transfer energy and momentum from large scales, feed the internal wavefield, and ultimately dissipate through turbulence. This cascade impacts the acoustic, optical, and biogeochemical properties of the water column, and feeds back to alter the larger scale circulation. Studies within the Ocean Mixing Group at OSU emphasize observations, innovative sensor / instrumentation development and integration, and ... |
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| Submesoscale Routes to Lateral Mixing in the Ocean |
30 Sep 2011 |
7 pages |
| Authors:
Amit Tandon; Amala Mahadevan; SOUTHEASTERN MASSACHUSETTS UNIV NORTH DARTMOUTH DEPT OF PHYSICS
|
| Long-Term Goals: To determine whether lateral mixing at O(1-10 km) scales is due to a balanced or unbalanced downscale cascade from the mesoscale, or due to local vertical mixing by internal waves and surface forcing. Objectives: Our work is testing hypothesis 3 of the white paper Scalable Lateral Mixing and Coherent Turbulence : Non-QG, submesoscale instabilities feed a forward cascade of energy, scalar and Ertel PV variance, which enhances both ... |
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| Ocean Surface Wave Optical Roughness - Innovative Measurement and Modeling |
30 Sep 2011 |
9 pages |
| Authors:
Johannes Gemmrich; VICTORIA UNIV (BRITISH COLUMBIA)
|
| LONG-TERM GOALS: This was the final year of the Radiance in a Dynamic Ocean (RaDyO) program. The primary research goals of the program were (1) to examine time-dependent oceanic radiance distribution in relation to dynamic surface boundary layer (SBL) processes; (2) to construct a radiance-based SBL model; (3) to validate the model with field observations; and (4) to investigate the feasibility of inverting the model to yield SBL conditions. As ... |
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| New Approaches to the Parameterization of Gravity-Wave and Flow-Blocking Drag due to Unresolved Mesoscale Orography Guided by Mesoscale Model Predictability Research |
30 Sep 2011 |
7 pages |
| Authors:
Stephen D Eckermann; NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV
|
| When surface flow impinges on orography with horizontal scales of 1-500 km, a variety of mesoscale dynamical responses can result, including gravity waves, upstream blocking, flow splitting and lee vortices. These dynamics produce important drag forces on the larger scale atmosphere. Because global numerical weather and climate prediction (NWCP) models under-resolve orography at these scales, all credible NWCP systems must include parameterizations of these missing orographic mesoscale drag (OMD) forces. ... |
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| Hydrodynamics and Roughness of Irregular Boundaries |
30 Sep 2011 |
7 pages |
| Authors:
Geno Pawlak; HAWAII UNIV HONOLULU DEPT OF OCEAN AND RESOURCES ENGINEERING
|
| The research goals of the work target accurate parameterization and modeling of nearshore waves, currents and turbulence in complex reef environments. A central theme of this work is the response of steady and oscillating flow to highly irregular, broad-banded roughness. Previous ONR supported study by the PI s group have quantified reef roughness, examined the hydrodynamic response to a variable roughness at small scales and explored the relationship between hydrodynamic ... |
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| Multi-Scale Prediction and Simulation of Localization Banding in Granular Media |
30 Sep 2011 |
7 pages |
| Authors:
Jose E Andrade; Ted Belytschko; NORTHWESTERN UNIV EVANSTON IL
|
| Shear bands are a critical factor in the response of granular materials, such as soils, rocks, and concrete. The objective of this research is to develop methods for accurately predicting the onset and propagation of deformation bands in granular media under extreme environments by developing an efficient multiscale simulation framework. The goal is to bridge continuum scale methods with the existing discrete methods to obtain an accurate multiscale model that ... |
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| Relaxation of Fermionic Excitations in a Strongly Attractive Fermi Gas in an Optical Lattice |
27 Sep 2011 |
6 pages |
| Authors:
Rajdeep Sensarma; David Pekker; Ana M Rey; Mikhail D Lukin; Eugene Demler; CALIFORNIA INST OF TECH PASADENA DEPT OF PHYSICS
|
| We theoretically study the relaxation of high energy single particle excitations into molecules in a system of attractive fermions in an optical lattice, both in the superfluid and the normal phase. In a system characterized by an interaction scale U and a tunneling rate tau, we show that the relaxation rate scales as approximately Ctexp[-alphaU(2)/tau(2)In(U/tau)] in the large U/tau limit. We obtain explicit expressions for the temperature and density dependent ... |
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| Minesweeping for Pressure Actuated Mines by Air Injection into a Water Column |
Sep 2011 |
101 pages |
| Authors:
John I Actkinson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The U.S. Navy historically has not had an adequate means to remotely pressure-sweep for mines at reasonable speeds and cost, and this is still the case. The Navy has addressed such threats, but countermeasures are time consuming and considered to be very resource intensive. During this thesis two sets of data were collected in tow tank experiments using two different sizes of Bubble Squid apparatus. This thesis is a continuation ... |
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| Phase Field Modeling of Twinning in Indentation of Transparent Crystals |
Sep 2011 |
38 pages |
| Authors:
J D Clayton; J Knap; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Continuum phase field theory is applied to study elastic twinning in calcite and sapphire single crystals subjected to indentation loading by wedge-shaped indenters. An order parameter is associated with the magnitude of stress-free twinning shear. Geometrically linear and nonlinear theories are implemented and compared, the latter incorporating neo-Hookean elasticity. Equilibrium configurations of deformed and twinned crystals are attained numerically via direct energy minimization. Results are in qualitative agreement with experimental ... |
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| Multiscale Modeling of Armor Ceramics: Focus on AlON |
Sep 2011 |
16 pages |
| Authors:
G A Gazonas; J W McCauley; I G Batyrev; D Casem; J D Clayton; D P Dandekar; R Kraft; B M Love; B M Rice; B E Schuster; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The computational modeling linkage from the atomistic to the continuum scales of homogeneous and discrete deformation mechanisms (twinning, cleavage, micro-cracking, stacking faults, et cetera), nano- and microstructure and defects, to dynamic failure processes in brittle materials should provide pathways to designing improved mechanical performance through controlled processing. This report will review results from an internal multiscale computational program in first-principles design of armor ceramics, with a focus on an optically ... |
|
| Low HAP/VOC Compliant Resins for Military Applications |
Sep 2011 |
979 pages |
| Authors:
John La Scala; S Boyd; K Andrews; T Glodek; C Lochner; P Myers; F Levine; D De Bonis; R Hayes; J Sands; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Liquid resins used for molding composite structures are a significant source of hazardous air pollutant (HAP) emissions. One method of reducing styrene emissions from vinyl ester (VE) resins is to replace some or all of the styrene with fatty acid-based monomers. Fatty acid monomers are ideal candidates because they are inexpensive, have low volatilities, and promote global sustainability because they are derived from renewable resources. This patented technology allows for ... |
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| Scalable Management of Enterprise and Data-Center Networks |
Sep 2011 |
151 pages |
| Authors:
Minlan Yu; PRINCETON UNIV NJ DEPT OF COMPUTER SCIENCE
|
| The networks in campuses, companies, and data centers are growing larger and becoming more complicated to manage. Today, network operators devote tremendous time and effort to three key management tasks--routing, access control, and troubleshooting. Rather than trying to make today's brittle networks easier to manage, we focus on new network designs that are inherently easier to manage and scale to many hosts, switches, and applications. We design and develop a ... |
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| Experimentally-Based Ocean Acoustic Propagation and Coherence Studies |
Sep 2011 |
11 pages |
| Authors:
Timothy F Duda; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEEP SUBMERGENCE LAB
|
| LONG TERM GOALS: The long term goal is to better understand fluctuating sound propagation conditions in two distinct ocean acoustic environment types. The first type is stratified shallow water where sound is highly bottom interacting. The second type is the mostly non bottom-interacting temperate deep-ocean sound channel. Reliable predictions of temporal and spatial variability of received underwater sound can improve processing and handling of signals of interest, including remediation of ... |
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| Fiedler Trees for Multiscale Surface Analysis |
Aug 2011 |
13 pages |
| Authors:
Matt Berger; Luis G Nonato; Valerio Pascucci; Claudio T Silva; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| In this work we introduce a new hierarchical surface decomposition method for multiscale analysis of surface meshes. In contrast to other multiresolution methods, our approach relies on spectral properties of the surface to build a binary hierarchical decomposition. Namely, we utilize the first nontrivial eigenfunction of the Laplace-Beltrami operator to recursively decompose the surface. For this reason we coin our surface decomposition the Fielder tree. Using the Fiedler tree ensures ... |
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| Epitaxial Nucleation on Rationally Designed Peptide Functionalized Interface |
19 Jul 2011 |
16 pages |
| Authors:
Raymond Tu; CITY COLL NEW YORK
|
| Over the course of the grant period we have applied a set of rationally designed interfacially confined peptides to explore the cooperative relationship between self-assembly and hybrid materials processing. This research report highlights our ability to apply the dynamics of surface active peptides to simultaneously control structure at two length scales, (1) the length scale associated with a fibrous peptide supramolecular assembly and (2) the length scale associated with a ... |
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| Use of Advanced Characterization Techniques to Study Structural and Compositional Transitions Across Solid State Interfaces (Preprint) |
Jul 2011 |
|
| Authors:
J Tiley; G B Viswanathan; R Srinivasan; H L Fraser; R Banerjee; S Nag; J Y Hwang; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| The atomic-scale study of solid-solid interfaces in complex multi-phase multi-component systems is a challenging but important endeavor. This article highlights the coupling of recently developed advanced characterization techniques, such as high resolution scanning transmission electron microscopy (HRSTEM), carried out in an aberration-corrected microscope, and 3D atom probe (3DAP) tomography, to address the structural and compositional transition at the atomic scale across solid-solid interfaces, such as the gamma/gamma interface in Ni-base ... |
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| Compilation of Pilot Personality Norms |
Jul 2011 |
59 pages |
| Authors:
Raymond E King; Erica Barto; Malcolm J Ree; Mark S Teachout; SCHOOL OF AEROSPACE MEDICINE WRIGHT PATTERSON AFB OH
|
| Aviators are a highly selected and distinguished occupational group, with Air Force pilots being at or near the apex. In this high-risk profession, errors can lead to significant costs in terms of human life, international relations, and national security. Furthermore, human error is often a causal factor in pilot training and mission-related aviation mishaps. Due to these high costs and risks, an understanding of the personality characteristics of pilots is ... |
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| Development of a Quadcon Refrigerated Container with First Generation Prototype Solar Adsorption Refrigeration System |
JUN 2011 |
101 pages |
| Authors:
J. D. Carruthers; ADVANCED TECHNOLOGY MATERIALS INC DANBURY CT
|
| Report for Broad Agency Announcement (BAA) Congressional Plus-up. The Army recognizes the merits of using renewable energy to power refrigeration systems aboard mobile cold-storage systems used for perishable rations in operational theaters. This report documents efforts to develop a solar-powered adsorption refrigerator for food refrigeration in a QuadCon container. The work was performed between October 2007 and April 2010 under a Broad Agency Announcement project funded as a Congressional Plus-Up ... |
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| The Inevitable War? |
20 MAY 2011 |
83 pages |
| Authors:
Richard K. Showalter; ARMY COMMAND AND GENERAL STAFF COLL FORT LEAVENWORTH KS SCHOOL OF ADVANCED MILITARY STUDIES
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| China and the United States have been competitors on a global scale since Deng Xiaoping changed China's trading policies in 1976. The policies resulted in increased tensions between the two nations over time. This monograph uses Commercial Liberalism and Power Transition Theory to describe conditions in two historical case studies that led to peace or war. These lessons are applied to today's relationship between China and the United States in ... |
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| Improving the Accuracy and Scalability of Discriminative Learning Methods for Markov Logic Networks |
MAY 2011 |
161 pages |
| Authors:
Tuyen N. Huynh; TEXAS UNIV AT AUSTIN
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| Many real-world problems involve data that both have complex structures and uncertainty. Statistical relational learning (SRL) is an emerging area of research that addresses the problem of learning from these noisy structured/ relational data. Markov logic networks (MLNs), sets of weighted rstorder logic formulae, are a simple but powerful SRL formalism that generalizes both rst-order logic and Markov networks. MLNs have been successfully applied to a variety of real-world problems ... |
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| Near-Inertial Wave Studies Using Historical Mooring Records and a High-Resolution General Circulation Model |
25 Apr 2011 |
6 pages |
| Authors:
Matthew H Alford; Harper Simmons; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
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| Knowledge of internal waves and ocean mixing is important f()r advancing the performance of operational and climate models, as well as for understanding local problems such as pollutant dispersal and biological productivity. Consequently, a long-term goal of the oceanographic community has been to develop a global internal wave prediction system analogous to systems already in place for surfuce waves. Early steps have been accomplished with simulations of internal tides at ... |
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