| Dislocation Dynamic Modeling in High Temperature Single Crystal Viscoplasticity (Preprint) |
Mar-2009 |
5 pages |
| Authors:
Brice N Cassenti; Alexander Staroselsky; PRATT AND WHITNEY EAST HARTFORD CT
|
 | We have developed a crystallographic-based viscoplastic model for nonisothermal high temperature deformation and coupled it with damage kinetics. Several damage mechanisms, namely the multiplication of mobile dislocations, void growth and including scale effects, caused by dislocation extrusions/intrusions, have been considered. We applied two body interaction concepts from chemical kinetics to include in our constitutive relations the generation and interaction of pinned and mobile dislocations. The relative importance of each of ... |
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| Development of the 2007 Chemical Decontaminant Source Document |
Mar-2009 |
551 pages |
| Authors:
Teri Lalain; Brent Mantooth; Tom Lynn; Zach Zander; Pamela Humphreys; SCIENCE APPLICATIONS INTERNATIONAL CORP GUNPOWDER MD
|
| The chemical decontaminant performance evaluation testing source document is the product of project BA06DEC414 for improved test methodology. The primary objective is to improve the rigor of existing test methods for the generation of defensible and comparable decontamination efficacy data for the quantitative determination of post-decontamination contact and vapor hazards and residual agent. Execution of these improved methods will yield higher fidelity data presented in appropriate context. The data generated ... |
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| Experimental/Computational Approach to Accommodation Coefficients and its Application to Noble Gases on Aluminum Surface (Preprint) |
03-Feb-2009 |
26 pages |
| Authors:
Andrew Ketsdever; Sergey F Gimelshein; Nathaniel Selden; Natalie E Gimelshein; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A technique is proposed to assess gas-surface accommodation coefficients. The technique utilizes the fact that radiometric forces exerted on heated objects immersed in rarefied gases are governed by the interaction of gas molecules with the surface. In the present implementation, it connects measurements of radiometric forces on a heated vane in the transitional flow regime with the kinetic modeling of the flow, and derives the accommodation coefficients through the successive ... |
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| Computational Prediction of Kinetic Rate Constants |
Feb-2009 |
27 pages |
| Authors:
Mark Ponton; Rodney J Bartlett; ACES QC LC GAINESVILLE FL
|
| The objective of this STTR has been to develop tools to make the evaluation of rate constants for gas phase reactions routine for many modest sized molecules. such quantities are critical input to atmospheric and combustion models. they also provide critical information to designing procedures to destroy stock piles of nerve agents, and other waste products. However, it is often very difficult to experimentally measure such rate constants, making 'predictive' ... |
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| Experimental and Numerical Analysis of Radiometric Forces on a Heated Circular Vane in Argon (Preprint) |
13-Jan-2009 |
16 pages |
| Authors:
N Gimelshein; S Gimelshein; N Selden; C Ngalande; A Ketsdever; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Radiometric force on a 0.12m circular vane is studied experimentally and numerically over a wide range of pressures that cover the flow regimes from near free molecular to near continuum. In the experiment, the vane is resistively heated to about 419 K on one side and 394 K on the other side, and immersed in a rarefied argon gas. The radiometric force is then measured on a nano- Newton thrust ... |
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| Integrated Computational/Experimental Study of Turbulence Modification and Mixing Enhancement in Swirling Jets |
07-Jan-2009 |
30 pages |
| Authors:
J Naughton; D Stanescu; S Heinz; R Semaan; M Stoellinger; C Zemtsop; WYOMING UNIV LARAMIE
|
| Swirling jet flows have been studied experimentally and computationally and the results have been compared with theory. Three-component Laser Doppler Anemometry (LDA) measurements have been carried out for swirling jets of various strengths and swirl distributions. Radial profiles of velocity have been obtained from the jet exit to 50 diameters downstream. The experimental results are consistent with previous results and with similarity theory for weakly swirling turbulent jets. However, the ... |
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| Wave Transformation Over Reefs: Evaluation of One-Dimensional Numerical Models |
Jan-2009 |
208 pages |
| Authors:
Zeki Demirbilek; Okey G Nwogu; Donald L Ward; Alejandro Sanchez; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
|
| Three one-dimensional (1D) numerical wave models are evaluated for wave transformation over reefs and estimates of wave setup, runup, and ponding levels in an island setting where the beach is fronted by fringing reef and lagoons. The numerical models are based on different governing equations. BOUSS-1D and RBREAK2 are phase-resolving models that respectively solve the time-dependent Boussinesq and shallow water equations. WAV1D solves the 1D wave-averaged energy conservation equation. Laboratory ... |
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| Transport Processes in Reacting Hydrothermal Flames with Applications to Military Waste Destruction in Supercritical Water and Geotechnical Rock Excavation |
Jan-2009 |
17 pages |
| Authors:
J W Tester; C Augustine; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
|
| A hydrothermal flame is a flame that exists in a supercritical aqueous medium and is characterized by steep temperature and density gradients. The overall objective of our project was to increase understanding of heat, mass, and momentum transport processes within hydrothermal flames. Specifically, we planned to study hydrothermal flame characteristics such as flame temperature and stability, and to develop a method for modeling heat and mass transport processes in the ... |
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| Canopy Penetration and Deposition of Barrier Sprays from Electrostatic and Conventional Sprayers |
Jan-2009 |
10 pages |
| Authors:
W C Hoffmann; J Hogsette; U Bernier; B Fritz; M Farooq; Y Huang; Y Lan; B Quinn; D Szumlas; V L Smith; T W Walker; C A Robinson; AGRICULTURAL RESEARCH SERVICE COLLEGE STATION TX
|
| An experimental study was conducted to investigate the usefulness of electrostatic and conventional sprayers for barrier applications. Two conventional and three electrostatic sprayers were used in the study. Usefulness of the sprayers was rated based on penetration of spray into and deposition onto 2 sides of leaves on natural vegetation. Bifenthrin (TalstarTM adulticide) was applied at labeled rate, fluorescent dye was added to the tank mix as tracer, and all ... |
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| Equivalent Roughness Height for Plane Bed Under Oscillatory Flow |
Jan-2009 |
15 pages |
| Authors:
Magnus Larson; Benoit Camenen; Atilla Bayram; CEMAGREF LYON (FRANCE)
|
| A new relationship between the roughness height and the main hydrodynamic and sediment parameters for plane beds under oscillatory conditions is presented. In order to derive such a relationship, a large data base encompassing plane-bed experiments was compiled from previous investigations and analyzed. Different methods to estimate the roughness height were investigated. Comparisons between the data and different existing predictive formulas for the bed roughness obtained from the literature were ... |
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| Lamb Wave Dispersion Compensation in Piezoelectric Wafer Active Sensor Phased-Array Applications |
Jan-2009 |
13 pages |
| Authors:
Victor Giurgiutiu; Buli Xu; Lingyu Yu; SOUTH CAROLINA UNIV COLUMBIA DEPT OF MECHANICAL ENGINEERING
|
| Lamb-wave testing for structural health monitoring is complicated by the dispersion nature of the wave modes. The dispersion effect will result in a propagated wave with longer time duration, deformed envelop shape as compared to its excitation counterpart, and hard to be interpreted. This paper first reviews the dispersion compensation and removal algorithms. Second, it compares these two methods by applying them to two widely used low-frequency Lamb wave modes: ... |
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| Demonstration Mobile Seismic Unit for Detecting Subterranean Passageways |
JAN 2009 |
165 pages |
| Authors:
Neil Anderson; Niaklas Putman; Steve Grant; A. Nasseri-Moghaddam; Peng Xie; Oleg Kovin; Preetam Modur; Colin Stagner; Evginey Torgashov; MISSOURI UNIV-ROLLA
|
| A mobile seismic unit for detecting shallow subterranean passageways was designed and constructed. The unit was successfully field tested and/or demonstrated at six known tunnel sites (tunnel diameters ranged from 0.6 4.0 m; tunnel depths ranged from 0.3 1.5 m). The locations of the six tunnels were determined with an average accuracy of 0.5 m; on average, one false positive was identified on each of the six test site data ... |
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| A New Approach for Investigating Crystal Stresses that Drive the Initiation of Fatigue-Induced Defects in Structural Alloys |
31-Dec-2008 |
15 pages |
| Authors:
Paul R Dawson; CORNELL UNIV ITHACA NY
|
| We have developed an approach to investigate crystals stresses during cyclic load by coordinating experiments and simulations at the size scale where fatigue induced defects initiate. Our efforts provided new understanding of the stress evolution during cyclic loading through a complementary process between the experimental measurement of lattice strain and the simulation results. The comparison of the experimental and the simulated lattice data culminated in a novel picture of how ... |
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| Transition Delay in Hypervelocity Boundary Layers by Means of CO2/Acoustic Instability Interactions |
08-Dec-2008 |
52 pages |
| Authors:
Graham Candler; Ivett A Leyva; Stuart Laurence; Amy W Beierholm; Hans G Hornung; Ross Wagnild; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A novel method to delay transition in hypervelocity flows over slender bodies by injecting CO2 into the boundary layer of interest is investigated. The results presented here consist of both experimental and computational data. The experimental data was obtained at Caltech's T5 reflected shock tunnel, while the computational data was obtained at the University of Minnesota. The experimental model was a 5 degree sharp cone, chosen because of its relevance ... |
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| Generic UAV Modeling to Obtain Its Aerodynamic and Control Derivatives |
Dec-2008 |
123 pages |
| Authors:
Choon S Chua; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis deals with two different software packages to obtain the aerodynamic and control derivatives for a generic unmanned air vehicle (UAV). These data has a dual application. Firstly, it is required in the Mathworks Simulink 6-degree-of-freedom model of a generic unmanned air vehicle to develop a robust controller and do a variety of trade-offs. Secondly, is also needed to tune the parameters of the existing real-time controllers such as ... |
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| Aerodynamic Predictions, Comparisons, and Validations Using MissileLab and Missile Datcom (97) |
Dec-2008 |
51 pages |
| Authors:
Hoon H Teo; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Aerodynamic prediction software is often used in the early stages of missile systems designed to quickly and accurately estimate the aerodynamics of a wide variety of missile configuration designs operating over many different flight regimes. It is also possible to use these empirical packages to validate flight data collected from wind tunnel tests and other open sources. Analysis of such data provides users with insights to the performance of a ... |
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| Development of Carbon/Carbon Composites with Through-Thickness Carbon Nanotubes for Thermal and Structural Applications |
Dec-2008 |
34 pages |
| Authors:
Zhiyong (Richard) Liang; Chuck Zhang; FAMU/FSU COLL OF ENGINEERING TALLAHASSEE FL DEPT OF INDUSTRIAL ENGINEERING
|
| Carbon/carbon composites offer lightweight thermal protection capable of producing excellent thermal materials. To further improve the thermal conductivity along the thickness direction and the interlaminar shear strength, we studied and demonstrated a novel method to stitch carbon nanotube yarns along the through-thickness direction of carbon fiber two-dimensional precursor felt perform to make novel 3D reinforced carbon/carbon (C/C) composites. By stitching nanotube yarns, high strength and thermal conductive CNTs were incorporated ... |
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| A Computational Framework Based on Variational LES Method for the Multi-Disciplinary Analysis of MAVS With Flapping Wings |
Dec-2008 |
8 pages |
| Authors:
Charbel Farhat; Ajaykumar Rajasekharan; STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING
|
| In this paper the three level formulation of a variational multi-scale (VMS) large eddy simulation (LES) method for compressible flow computations is extended for applications involving moving/deforming grids. A consistent method to improve the VMS-LES constant dynamically as the flow develops (dynamic VMS-LES) is also extended for dynamic grid applications. Two applications of VMS-LES for the simulation of separated flow over moving NACA-0012 extruded airfoil is then presented. The first ... |
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| Controlling Ethylene for Extended Preservation of Fresh Fruits and Vegetables |
Dec-2008 |
6 pages |
| Authors:
Peter Lavigne; Zach Patterson; Shubham Chandra; Derek Affonce; Karen Benedek; Phil Carbone; ARMY NATICK RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
|
| This paper describes work conducted to enhance the quality of fresh produce delivered to troops around the world. Specifically, the program objective is to control ethylene produced by fresh fruits and vegetables (FF&V) in refrigerated containers with the use of a novel Ethylene Elimination Unit (EEU). This paper describes the analytical, experimental, and design work conducted to establish the feasibility of the EEU. Analytical modeling and process simulation were used ... |
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| Threshold Voltage Instability in A-Si:H TFTS and the Implications for Flexible Displays and Circuits |
Dec-2008 |
9 pages |
| Authors:
D Allee; E Forsythe; G Raupp; K Baugh; E Bawolek; Z Li; N Darbanian; S Venugopal; R Shringarpure; L Clark; D Morton; ARIZONA STATE UNIV TEMPE
|
| After a brief review of the characteristics of electrical stress degradation of flexible, amorphous silicon thin film transistors, the implications for various types of flexible circuitry including active matrix backplanes, integrated drivers and general purpose digital circuitry are examined. A circuit modeling tool that enables the prediction of complex circuit degradation is presented. Experimental results for a variety of flexible digital circuits including programmable logic arrays and memories are presented. ... |
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| Advances in Modeling and Simulation of Rotorcraft Noise and Associated Impacts on Survivability |
Dec-2008 |
9 pages |
| Authors:
Daniel Newman; Thomas Doligalski; Robert Minniti; DEFENSE ADVANCED RESEARCH PROJECTS AGENCY ARLINGTON VA TACTICAL TECHNOLOGY OFFICE
|
| The acoustic signature of a rotorcraft is often the primary means of detection and identification by enemy forces in the modern battlespace. Additionally, this detection is often accomplished without the need for the sophisticated sensing equipment required for other signature components. While this vulnerability has existed for many generations of rotorcraft, the tools for predicting the acoustic signature and understanding its impact on mission survivability have lagged in development. This ... |
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| Estimating High-Resolution Directional Clutter Maps in Forested Terrain Using Airborne Lidar Data |
Dec-2008 |
9 pages |
| Authors:
K C Slatton; Pang-Wei Liu; Heezin Lee; Mike Campbell; FLORIDA UNIV GAINESVILLE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| A priori knowledge of clutter environments is critical for understanding target detection performance from airborne sensors and optimally predicting future performance to aid in mission planning. Modern airborne lidar, also known as Airborne Laser Swath Mapping (ALSM), systems can acquire decimeter scale measurements of the 3D structure in forests and urban areas. From these measurements, high resolution clutter maps that account for variations in both 3D Cartesian coordinates and viewing ... |
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| Computational Design of Biomimetic Gels With Properties of Human Tissues |
Dec-2008 |
9 pages |
| Authors:
J Andzelm; Y Sliozberg; J K Brennan; M VanLandingham; V Pryamitsyn; V Ganesan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The effective design of body armor requires the use of biomimicking materials that accurately and robustly reproduce the characteristic mechanical behavior of human tissues. The mechanical performance of the soft tissues is determined by their viscoelastic properties and for this reason the optimal soft tissue surrogate must viscoelastically mimic the original tissue. One traditional tissue surrogate material is a water-based gelatin gel that has poor environmental stability and limited tailorability. ... |
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| Modeling Combustion Chamber Dynamics of Impinging Stream Vortex Engines Fueled With Hydrazine-Alternative Hypergols |
Dec-2008 |
9 pages |
| Authors:
C C Chen; M J Nusca; M J McQuaid; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| To advance the development of Impinging Stream Vortex Engines (ISVEs) for tactical missile propulsion system applications, a computational fluid dynamics (CFD) modeling capability has been developed and employed to simulate the combustion chamber dynamics of various ISVE designs. Simulations of firstgeneration ISVE configurations fueled with monomethylhydrazine/ red fuming nitric acid (MMH/RFNA) led to insights that inspired a combustion chamber design change, and simulations of an ISVE with the new feature ... |
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| DNS and RANS Simulation of Dispersion Downstream of an Obstacle |
Dec-2008 |
9 pages |
| Authors:
Gianluca Iaccarino; Riccardo Rossi; BOLOGNA UNIV (ITALY)
|
| Dispersion in the wake of an obstacle is studied as a step towards the analysis of bio-agent release in urban environments. Available experimental measurements are used to compare in details numerical predictions obtained using Reynolds-Averaged Navier-Stokes (RANS) techniques and Direct Numerical Simulations (DNS). In particular, turbulent scalar fluxes are compared to assess the quality of simple closure based on eddy diffusivity assumptions. The results obtained using different RANS closures show ... |
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| Observation of Nonlinear Transmission Enhancement in Cavities Filled With Nonlinear Organic Materials |
01-Nov-2008 |
8 pages |
| Authors:
Dan T Nguyen; ChuanXiang Sheng; Jayan Thomas; Robert Norwood; Brian Kimball; Diane M Steeves; Nasser Peyghambarian; ARIZONA UNIV TUCSON
|
| We show experimental and theoretical results for enhancement of nonlinear transmission (NT) in moderate finesse cavities filled with nonlinear organic materials (NLOM). Our design for enhancement of nonlinear transmission using micro NLOM cavities compared with reference samples of the same material show that single cavities can enhance the nonlinear response by a factor of 10 or greater under high-absorption conditions. Further enhancement can be achieved in multiple-cavity structures. Other advantages ... |
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| Multiscale Models of Multifunctional Composites for On-Board Damage Detection and Failure Prevention |
08-Oct-2008 |
12 pages |
| Authors:
W A Curtin; BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
|
| Analytic and numerical models were developed to predict the dependence of electrical resistance on internal fiber damage in carbon-fiber-reinforced polymer (CFRP) composites, so as to make electrical resistance measurement a tool for damage detection and prognosis in CFRP components. The models show that electrical resistance is more sensitive to damage than elastic modulus, that resistance change can be used to detect inadvertent overloads, that the remaining fatigue life after overload ... |
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| Extension of Viscoplasticity Based on Overstress to Capture the Effects of Prior Aging on the Time Dependent Deformation Behavior of a High-Temperature Polymer: Experiments and Modeling |
Oct-2008 |
217 pages |
| Authors:
Amber J McClung; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 288 degrees C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain controlled loading were examined. The experimental data ... |
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| Evaluation of the C* Model for Addressing Short Fatigue Crack Growth |
Oct-2008 |
|
| Authors:
K F Walker; W Hu; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AIR VEHICLES DIV
|
 | The C* model has been proposed to account for the breakdown of K-similitude which occurs for short cracks. The model is based on the concept that crack growth rate is dependent not only on the stress intensity factor range, but also on crack length. This report evaluates the C* model using experimental data from the open literature. For comparison, two other models, the El Haddad model and the FASTRAN model, ... |
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| Prestall Behavior of a Transonic Axial Compressor Stage via Time-Accurate Numerical Simulation |
Oct-2008 |
16 pages |
| Authors:
Jen-Ping Chen; Michael D Hathaway; Gregory P Herrick; OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS
|
| CFD calculations using high-performance parallel computing were conducted to simulate the pre-stall flow of a transonic compressor stage, NASA compressor Stage 35. The simulations were run with a full-annulus grid that models the 3D, viscous, unsteady blade row interaction without the need for an artificial inlet distortion to induce stall. The simulation demonstrates the development of the rotating stall from the growth of instabilities. Pressure-rise performance and pressure traces are ... |
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| Computer Simulation of a 155-mm Projectile in a Scat Gun Assembly |
01-Sep-2008 |
34 pages |
| Authors:
Kenneth P Walsh; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ
|
| This report presents the results of a computer simulation of a 45.36 kg 155-mm projectile as it moves through a scat gun assembly using a FORTRAN program. The experimental data was taken from a test performed by the Analysis Engineering and Technical Division at the U.S. Army Armament Research, Development and Engineering Center, Picatinny Arsenal, New Jersey on 7 April 2007 (test CBR5). The data was filtered using an Abaqus ... |
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| Investigation of Hyperfine Structure of Various Materials Using All-Electron Full-Potential Program |
01-Sep-2008 |
6 pages |
| Authors:
Kanichi Nakagawara; M S Bahramy; H Adachi; Y Kawazoe; NIHON GENE RESEARCH LABS INC SENDAI (JAPAN)
|
| A specific example of first-principles hyperfine parameters is presented. Within density functional theory, the magnetic hyperfine properties are studied for a model molecule representing the heme moiety of nitrosylmyoglobin using so called all-electron mixed basis method. The isotropic hyperfine parameters are calculated for the N atoms of nitric oxide agent and proximal histidine group by considering various values for Fe-N(NO) bond distance and Fe-N-O angle. The values are compared with ... |
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| Mass Remaining During Evaporation of Sessile Drop |
01-Sep-2008 |
35 pages |
| Authors:
James E Danberg; SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) ABINGDON MD
|
| A theory to predict the evaporation rate of HD (mustard agent) for the special case of a glass substrate has been developed. This is an important reference case for the wind tunnel and field test measurements of the HD evaporation rate. The HD drop is treated as a spherical segment with a constant base diameter characterized by the variation of the droplet shape factor (height to base diameter) or contact ... |
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| Acoustic Scattering from Sand Dollars (Dendraster excentricus): Modeling as High Aspect Ratio Oblate Objects and Comparison to Experiment |
Sep-2008 |
|
| Authors:
Gregory C Dietzen; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| Benthic shells can contribute greatly to the scattering variability of the ocean bottom, particularly at low grazing angles. Among the effects of shell aggregates are increased scattering strength and potential subcritical angle penetration of the seafloor. Sand dollars (Dendraster excentricus) occur commonly in the ocean and have been shown to be significant scatters of sound. In order to understand more fully the scattering mechanisms of these organisms, the scattering from ... |
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| The Chesapeake Bay Interpretive Buoy System |
Sep-2008 |
5 pages |
| Authors:
Doug Wilson; NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION ANNAPOLIS MD CHESAPEAKE BAY OFFICE
|
| The Chesapeake Bay Interpretive Buoy System (CBIBS) is an innovative system to collect, transmit and interpret real-time environmental data from the Chesapeake Bay to a wide variety of constituents - including scientists, on-the-water users, educators, and natural resource decision-makers - and to fill critical observational gaps in the Chesapeake Bay. CBIBS is a component of the Chesapeake Bay Observing System (CBOS) and the US Integrated Ocean Observing System (IOOS), addressing ... |
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| Navier-Stokes Predictions of Dynamic Stability Derivatives: Evaluation of Steady-State Methods |
Sep-2008 |
44 pages |
| Authors:
James DeSpirito; Sidra I Silton; Paul Weinacht; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| The prediction of the dynamic stability derivatives-roll-damping, Magnus, and pitch-damping moments-were evaluated for three spin-stabilized projectiles using steady-state computational fluid dynamic (CFD) calculations. Roll-damping CFD predictions were found to be very good across the Mach number range investigated. Magnus moment predictions were very good in the supersonic flight regime; however, the accuracy varied in the subsonic and transonic flight regime. The best Magnus moment prediction in the subsonic flight regime ... |
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| Reliability - Based Performance Assessment of Damaged Ships |
Sep-2008 |
237 pages |
| Authors:
Fei Sun; Y Pu; H S Chan; R S Dow; M Shahid; P K Das; NEWCASTLE UNIV NEWCASTLE UPON TYNE (UNITED KINGDOM) SCHOOL OF ELECTRICAL ELECTRONIC AND COMPUTER ENGINEERING
|
| The objective of this project is to develop a procedure and tools for operators and decision makers to assess the residual ultimate hull girder strength of damaged ships for a given damage scenario. In this study, some tools for predicting wave-induced loads and assessing ultimate hull girder strength have been further developed. In particular, 2D linear and non-linear methods have been applied to a ship model to calculate the wave-induced ... |
|
| Acoustic Scattering from Sand Dollars (Dendraster excentricus): Modeling as High Aspect Ratio Oblate Objects and Comparison to Experiment |
SEP 2008 |
161 pages |
| Authors:
Gregory C. Dietzen; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Benthic shells can contribute greatly to the scattering variability of the ocean bottom, particularly at low grazing angles. Among the effects of shell aggregates are increased scattering strength and potential subcritical angle penetration of the seafloor. Sand dollars (Dendraster excentricus) occur commonly in the ocean and have been shown to be significant scatters of sound. In order to understand more fully the scattering mechanisms of these organisms, the scattering from ... |
|
| Experimental Test of Nonclassicality for a Single Particle |
Aug-2008 |
10 pages |
| Authors:
Alan Migdall; Valentina Schettini; Sergey V Polyakov; Ivo P Degiovanni; Giorgio Brida; Marco Genovese; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
|
| In a recent paper a test of nonclassicality for a single qubit was proposed. Here, we discuss the class of hidden variables theories to which this test applies and present an experimental realization. |
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| TNO Contribution to the Quest 303 Trial - Human Performance Assessed by a Vigilance and Tracking Test, a Multi-Attribute Task, and by Dynamic Visual Acuity (TNO Bijdrage aan het Quest 303 Onderzoek) |
01-Jul-2008 |
|
| Authors:
J E Bos; P J Valk; M A Hogervorst; K Munnoch; D Perrault; J L Colwell; TNO DEFENCE SECURITY AND SAFETY SOESTERBERG (NETHERLANDS)
|
| A multi-national sea trial on the effects of ship motions on human performance was performed off the coast of Canada, in early 2007. Primary goal: To obtain subjective and objective measures for human task performance, possibly affected by real ship motion. TNO participated with a Vigilance and Tracking Test, a Multi-Attribute Task, and a Dynamic Visual Acuity test. The experiment was conducted in three phases: a pre-exposure phase in harbour, ... |
|
| Photochemical Tissue Bonding for Military Medical Applications |
30-Jun-2008 |
22 pages |
| Authors:
Dennis McCal; Scott Prahl; NLIGHT PHOTONICS CORP VANCOUVER WA
|
| Report developed under STTR contract for topic number AF07-T033. The overall goal is to develop a complete system for micro-anastomosis of blood vessels. This involves (1) a unique laser system that uses water as the absorbing chromophore, (2) a clinically useful handpiece that is appropriate for microsurgery, (3) a novel albumin stent to support the vessel during anastomosis, (4) in vitro testing of the device to assess thermal damage, strength, ... |
|
| Annexin II-Dependent Mechanism of Breast Cancer Progression |
01-Jun-2008 |
9 pages |
| Authors:
Mahesh C Sharma; DREXEL UNIV PHILADELPHIA PA
|
| Angiogenesis and metastasis are two processes that are central to the progression of cancer. As such, they have become important targets for the development of anti-cancer agents. Invasive and metastatic cancers of the breast are distinguished by their propensity of newly formed blood vessels (neoangiogenesis). Neoangiogenesis is a significant independent prognostic indicator in early stage breast cancer (1). Delineating the molecular mechanism(s) of neoangiogenesis may provide new insights into the ... |
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| Modeling Magnetic Core Loss for Sinusoidal Waveforms |
01-Jun-2008 |
|
| Authors:
Colin J Dunlop; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| Among the challenging unsolved technical problems that have plagued the minds of scientist and engineers throughout the 20th and 21st century is the development of a quantifiable model to accurately estimate or explain Core Power Losses (CPL). Theoretical advances in magnets led to many model proposals, but as these models were experimentally examined, they quickly lost their validation. Many of the current models use manufacturer's material estimates to form limited ... |
|
| Real-Time Terahertz Imaging Using a Quantum Cascade Laser and Uncooled Microbolometer Focal Plane Array |
01-Jun-2008 |
101 pages |
| Authors:
Barry N Behnken; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Real-time imaging in the terahertz (THz) spectral range was achieved using an uncooled, 160 120 pixel infrared microbolometer camera and a milliwatt-scale quantum cascade laser (QCL). By replacing the camera's original focusing optics with a Tsurupica-based lens and minimizing diffraction effects incurred by the QCL output beam, an imaging scheme was developed in which the camera's focal plane array successfully detected wavelengths that are more than an order of magnitude ... |
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| Curvature Nonlinearity Measure and Filter Divergence Detector for Nonlinear Tracking Problems (Postprint) |
Jun-2008 |
9 pages |
| Authors:
Ruixin Niu; Pramod K Varshney; Mark Alford; Adnan Bubalo; Eric Jones; Maria Scalzo; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
|
| Experimental results show that for a weekly nonlinear tracking problem, the extended Kalman filter and the unscented Kalman filter are good choices, while a particle filter should be used for problems with strong nonlinearity. To quantitatively determine the nonlinearity of a nonlinear tracking problem, we propose two types of measures: one is the differential geometry curvature measure and the other is based on the normalized innovation squared (NIS) of the ... |
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| Sinusoidal Vertical Motion of a Sonobuoy Suspension: Experimental Data and a Theoretical Model |
Jun-2008 |
|
| Authors:
David M F Chapman; Dusko B A Kezele; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
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| To isolate its acoustic sensor from the large vertical motions of the buoy at the ocean surface, a typical sonobuoy employs a low-pass mechanical filter comprising a bungee cord (spring) and a damper disk (hydrodynamic added mass and damping). If the system were to behave as a driven simple harmonic oscillator, the transfer function of vertical motion would roll off at 40 dB/decade above resonance; however, experimental systems of this ... |
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| An Efficient Method for Calculating Surface Temperature and Heat Flux Based on Embedded Temperature Sensors (Preprint) |
09-May-2008 |
11 pages |
| Authors:
Edward B Coy; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| Approximate analytical solutions have been obtained for surface temperature and heat flux for the case of two embedded temperature sensors. The solutions have been verified and the range of validity has been established using several methods including comparisons with an exact analytical solution for a linear problem and numerical calculations for a non-linear problem. The performance of the model is presented in both the frequency domain and the time domain. ... |
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| Results of Fatigue Tests of Bare AF1410 Steel Unnotched Flat Plates with Surface Corrosion Damage. Engineering Data Report |
08 MAY 2008 |
77 pages |
| Authors:
David T. Rusk; Annette Arocho; Jennifer Pierce; Garry Abfalter; NAVAL AIR SYSTEMS COMMAND PATUXENT RIVER MD STRUCTURES DIV
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| The global maritime operating environment of U.S. Naval Aviation assets necessitates their prolonged exposure to severe corrosive environments. The resulting corrosion damage on flight critical structural components has a significant adverse impact on fleet readiness and total ownership costs. To address these issues, NAVAIR has initiated a multi-year research program to investigate and quantify the fatigue life reduction due to corrosion on high-strength steels, and to develop models and metrics ... |
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| Predicting Bone Metastatic Potential of Prostate Cancer via Computational Modeling of TGF-Beta Signaling |
01-May-2008 |
55 pages |
| Authors:
Carlton R Cooper; Baratunde Ogunnaike; DELAWARE UNIV NEWARK
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| This hypothesis generation project involved the development of a computational model of the TGF-beta signaling pathway and investigating whether such a model can be used to generate hypotheses regarding metastatic potential of prostate cancer (PCa). The primary deliverable of the investigation is a comprehensive quantitative model of TGF-beta signaling that is representative of a wide variety of experimental data collected in different labs worldwide; the primary outcome is the following ... |
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| Potential Flow Forces and Moments from Selected Ship Flow Codes in a Set of Numerical Experiments. Appendix A - Time History Plots for Prescribed Heave Motion of Model 5613 |
May-2008 |
675 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
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| This appendix contains all the plots and tables for the simulations of task 1 that involve 1-DOF prescribed heave motion of Model 5613 scaled to the length 154 m. Each of Figures A-1 through A-300 contains time-history plots of the results from all codes for a single variable during one period of motion. If the code runner did not supply the data, the data vanish identically, or the data are ... |
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