| Detecting Pitch and Yaw and In-flight Damping with Optical Chronographs |
30 Nov 2012 |
5 pages |
| Authors:
Elya R Courtney; Amy C Courtney; Michael W Courtney; AIR FORCE ACADEMY COLORADO SPRINGS CO
|
 | A bullet can leave the barrel with a significant yaw angle (or tip off rate leading to pitch and yaw) and then pitch and yaw in an oscillatory manner as the peak pitch and yaw angles slowly decrease as the bullet flies downrange. This paper presents an experimental design for detecting the in-flight damping and test results which support the theory of damping of pitch and yaw. Three chronographs were ... |
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| Computational Analysis of Intersubject Variability and Thrombin Generation in Dilutional Coagulopathy |
Nov 2012 |
13 pages |
| Authors:
Alexander Y Mitrophanov; Frits R Rosendaal; Jaques Reifman; ARMY MEDICAL RESEARCH AND MATERIEL COMMAND FORT DETRICK MD
|
| BACKGROUND: Blood dilution is a frequent complication of massive transfusion during trauma and surgery. This article investigates the quantitative effects of blood plasma dilution on thrombin generation in the context of intersubject variability. STUDY DESIGN AND METHODS: A thoroughly validated computational model was used to simulate thrombin generation curves for 472 healthy subjects in the Leiden Thrombophilia Study. Individual thrombin curves were calculated for undiluted blood and for different dilution ... |
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| Does Childhood Diarrhea Influence Cognition Beyond the Diarrhea-Stunting Pathway? |
31 Oct 2012 |
8 pages |
| Authors:
Christa L Walker; Laura Lamberti; Linda Adair; Richard L Guerrant; Andres G Lescano; Reynaldo Martorell; Relana C Pinkerton; Robert E Black; JOHNS HOPKINS UNIV BALTIMORE MD BLOOMBERG SCHOOL OF PUBLIC HEALTH
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| Diarrhea is a leading cause of morbidity among children under 5 years of age in low- and middle-income countries yet the additional effects and sequelae, such as cognitive impairment associated with diarrhea, have not been quantified. We quantified the association between diarrhea prevalence and cognitive outcomes while controlling for linear growth in 4 study populations. Cognition was assessed using different methods across sites and was expressed in standardized units. We ... |
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| Dissolution Rate of Propellant Energetics from Nitrocellulose Matrices |
Sep 2012 |
131 pages |
| Authors:
Susan Taylor; Katerina Dontsova; Susan Bigl; Colleen Richardson; James Lever; Jonathan Pitt; John P Bradley; Marianne Walsh; Jiri Simunek; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
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| During firing, propellant residues are scattered onto the soil surface where their energetic compounds can be dissolved by precipitation. The residues, like the unfired propellants, are composed of nitrocellulose imbibed with either 2,4-DNT (single-base), nitroglycerin (NG) (double-base) or NG and nitroguanidine (NQ) (triple-base). Although nitrocellulose is insoluble, 2,4-DNT, NG, and NQ are soluble; and 2,4-DNT and NG are also toxic. Consequently, data on how quickly 2,4-DNT, NG, and NQ are ... |
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| Metamaterial for Radar Frequencies |
Sep 2012 |
82 pages |
| Authors:
Szu H Tan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The objective of this thesis is to investigate a new design of periodic metamaterial (MTM) structure for radar crosssection (RCS) reduction application on aircraft and ships. MTMs are man-made materials, not found in nature, that exhibit unusual properties in the radio-, electromagnetic-, and optical-wave bands. The cells of these periodic MTM structures must be much smaller than the wavelength of the frequency of interest. In a MTM, the structure and ... |
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| Modeling and Design of Mixed-coherence Optical Stacks |
Sep 2012 |
24 pages |
| Authors:
William Beck; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| A Mathematica-based program for designing layered optical structures is described that can compute the optical properties at an arbitrary angle of incidence for stacks containing anisotropic and dispersive materials as well as stacks that contain a mixture of coherent and incoherent sections. The program can be used to calculate the properties of a fully specified optical stack or can be used to optimize some property of the stack by varying ... |
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| Measuring the Electro-Optic Coefficients of Bulk-poled Polymers |
Sep 2012 |
20 pages |
| Authors:
Robert C Hoffman; Joshua A Orlicki; George R Martin; Robert Lambeth; MyVan Baranoski; ARMY RESEARCH LAB ADELPHI MD
|
| This report describes the construction of an optical test system to measure the electro-optic coefficients of poled polymers directly. The poling process in polymers is the spontaneous orientation of the dissolved dye molecule, the chromophore, in the presence of an applied electric field. This spontaneous orientation confers upon the poled polymer a variety of useful optical effects, the linear electro-optic effect being chief among them. The optical test system measures ... |
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| Hydrodynamics and Marine Optics during Cold Fronts at Santa Rosa Island, Florida |
Sep 2012 |
16 pages |
| Authors:
Timothy R Keen; Robert H Stavn; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| Observations of optical and hydrodynamic processes were made on the open beach on Santa Rosa Island, Florida, in March 1995. This study focuses on the passage of two cold fronts. The observations have been supplemented by a bio-optical model, a suite of hydrodynamic models to simulate coastal flows forced by waves, tides, local wind, and coastal sea level; and a geo-optical model that predicts scattering by mineral particles resuspended by ... |
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| Physical Performance Assessment in Military Service Members |
Aug 2012 |
7 pages |
| Authors:
Jason M Wilken; Benjamin J Darter; Stephen L Goffar; Jesse C Ellwein; Rachel M Snell; Eric A Tomalis; Scott W Shaffer; BROOKE ARMY MEDICAL CENTER FORT SAM HOUSTON TX
|
| Few established measures allow effective quantification of physical performance in severely injured service members. We sought to establish preliminary normative data in 180 healthy, active-duty service members for physical performance measures that can be readily implemented in a clinical setting. Interrater and test-retest reliability and minimal detectable change (MDC) values were also determined. Physical performance testing included self-selected walking velocity on level and uneven terrain, timed stair ascent, the sit-to-stand ... |
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| NATO Independent Cost Estimating and the Role of Life Cycle Cost Analysis in Managing the Defence Enterprise (Estimation independante des couts de l'OTAN et role de l'analyse des couts globaux de possesssion au sen de l'OTAN) |
Aug 2012 |
254 pages |
| Authors:
NATO RESEARCH AND TECHNOLOGY ORGANIZATION NEUILLY-SUR-SEINE (FRANCE)
|
| Building upon the efforts of SAS-028, SAS-054 and SAS-069, the goal of SAS-076 was to prove the concepts of these earlier RTO SAS works on Life Cycle Cost Analysis by rigorously applying the guidelines to generate sound, reliable, Independent Cost Estimates (ICE) of major weapon system acquisition programs of current, international interest: HMS Rotterdam and HMS Johan de Witt Landing Platform Docks (LPD) of the Netherlands; and NATO's Alliance Ground ... |
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| Correlated and Zonal Errors of Global Astrometric Missions: A Spherical Harmonic Solution |
Jul 2012 |
8 pages |
| Authors:
V V Makarov; B N Dorland; R A Gaume; G S Hennessy; C T Berghea; R P Dudik; H R Schmitt; NAVAL OBSERVATORY WASHINGTON DC
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| We propose a computer-efficient and accurate method of estimating spatially correlated errors in astrometric positions, parallaxes, and proper motions obtained by space- and ground-based astrometry missions. In our method,the simulated observational equations are set up and solved for the coefficients of scalar and vector spherical harmonics representing the output errors rather than for individual objects in the output catalog. Both accidental and systematic correlated errors of astrometric parameters can be ... |
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| Next Generation Large Mode Area Fiber Technologies for High Power Fiber Laser Arrays |
08 Jun 2012 |
77 pages |
| Authors:
Almantas Galvanauskas; H Winful; Peter Dragic; E Honea; Stefan Heinemann; B Samson; MICHIGAN UNIV ANN ARBOR
|
| This program has successfully accomplished its main objective in that large core single-mode Ge-doped and Yb-doped CCC fibers have been developed as a platform for monolithically-integrated building blocks (individual laser channels) of high power beam-combined fiber laser arrays. Robust single-mode performance of CCC fibers with core sizes of up to 60m has been rigorously demonstrated. Various CCC fiber based high power lasers have been also demonstrated, including 600W SBS-free single-frequency ... |
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| Optical Properties and Radiation-Enhanced Evaporation of Nanofluid Fuels Containing Carbon-Based Nanostructures |
29 May 2012 |
8 pages |
| Authors:
Yanan Gan; Li Qiao; PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS
|
| The present paper experimentally determined the evaporation characteristics of nanofluid fuels with stable suspension of carbon-based nanostructures under radiation absorption in the ultraviolet-visible range. The results show that the evaporation rates of the ethanol-based nanofluids containing multiwalled carbon nanotubes (MWCNTs) or carbon nanoparticles (CNPs) are both higher than the evaporation rate of pure ethanol. Additionally, ethanol fuel with the addition of MWCNTs has a higher droplet temperature and a higher ... |
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| Forecasting F10.7 with Solar Magnetic Flux Transport Modeling (Postprint) |
03 Apr 2012 |
14 pages |
| Authors:
C J Henney; W A Toussaint; S M White; C N Arge; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
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| A new method is presented here to forecast the solar 10.7 cm (2.8 GHz) radio flux, abbreviated F10.7, utilizing advanced predictions of the global solar magnetic field generated by a flux transport model. Using indices derived from the absolute value of the solar magnetic field, we find good correlation between the observed photospheric magnetic activity and the observed F10.7 values. Comparing magnetogram data observed within 6 hours of the F10.7 ... |
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| Analysis of Social Network Measures with Respect to Structural Properties of Networks |
Mar 2012 |
79 pages |
| Authors:
Joshua D Guzman; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Social Network Analysis (SNA), the study of social interactions within a group, spans many different fields of study, ranging from psychology to biology to information sciences. Over the past half century, many analysts outside of the social science field have taken SNA concepts and theories and have applied them to an array of networks in the hope of formulating mathematical descriptions of the relations within the network of interest. More ... |
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| Pliant Micro Membrane-Wing Tip Vorticity Estimation Using Strain Sensitive Active Materials |
Feb 2012 |
25 pages |
| Authors:
Roberto Albertani; OREGON STATE UNIV CORVALLIS SCHOOL OF MECHANICAL INDUSTRIAL AND MANUFACTURING ENGINEERING (MIME)
|
| A mathematical correlation between wing-membrane discrete strains, wing lift and tip vorticity intensity, with simplified assumptions, was formulated and demonstrated. Wing circulation and lift estimation from tip vorticity, obtained via PIV measurements correlated qualitatively well with sting balance data from wind tunnel tests. The elastic pliant wing membrane shape under aerodynamic loads was estimated using a discrete number of strain information simulating patches of strain sensitive sensors on the surface ... |
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| Pulsed Plasma Arrays for Tubulence Control |
31 Jan 2012 |
16 pages |
| Authors:
Haris J Catrakis; CALIFORNIA UNIV IRVINE
|
| The PI successfully achieved active control of flow separation using dielectric barrier discharge plasma actuation on a hemisphere mounted on an elevated flat surface in a wind tunnel. Visualization of streaklines in the flow around the hemisphere at Re = 40,000 for control-on vs. control-off showed a reduction in the size of the separation region with active flow control. Measurement of the surface pressure coefficient also showed a recovery in ... |
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| Comparing Advertised Ballistic Coefficients with Independent Measurements |
17 Jan 2012 |
12 pages |
| Authors:
Emily Bohnenkamp; Bradford Hackert; Maurice Motley; Michael Courtney; AIR FORCE ACADEMY COLORADO SPRINGS CO
|
| This report addresses the question of ballistic coefficient accuracy. Ballistic coefficients of bullets are important because under or over estimates of ballistic coefficients can dramatically impact predictions of long range trajectory, wind drift, and impact energy. This project compares ballistic coefficients advertised by four well-known bullet companies (Hornady, Nosler, Sierra, and Barnes) with those measured by an independent source (Bryan Litz). G1 and G7 ballistic coefficients were determined using calculations ... |
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| Does Polishing a Rifle Bore Reduce Bullet Drag? |
17 Jan 2012 |
5 pages |
| Authors:
Emily Bohnenkamp; Maurice Motley; Michael Courtney; AIR FORCE ACADEMY COLORADO SPRINGS CO
|
| The experiment reported in this article addresses whether polishing a rifle bore reduces the aerodynamic drag of bullets. It was hypothesized that by polishing a rifle bore the aerodynamic drag of bullets would be reduced because a smoother bore would result in smoother rifling marks and thus lower drag. A Remington 700 5R Mil-Spec chambered in 300 Winchester Magnum was used. The bullets used were a 155.5 grain Berger Fullbore ... |
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| More Inaccurate Specifications of Ballistic Coefficients |
02 Jan 2012 |
8 pages |
| Authors:
Alex Halloran; Colton Huntsman; Chad Demers; Michael Courtney; AIR FORCE ACADEMY COLORADO SPRINGS CO
|
| A ballistic coefficient (BC) can be determined by using two chronographs a measured distance away from each other and shooting a bullet so the velocity is measured by the two devices. Ballistic modeling software requires accurate measurement of ballistic coefficients to accurately predict downrange trajectories, wind drift, and retained energy. This article presents new measurements for 21 different bullets and shows that BCs can differ significantly from the claims of ... |
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| Effectiveness of Computerized Oculomotor Vision Screening in a Military Population: Pilot Study |
Jan 2012 |
23 pages |
| Authors:
Jose E Capo-Aponte; Aaron K Tarbett; Thomas G Urosevich; Leonard A Temme; Navjit K Sanghera; Melvyn E Kalich; ARMY AEROMEDICAL RESEARCH LAB FORT RUCKER AL
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| The prevalence of oculomotor dysfunctions associated with blast-induced mild traumatic brain injury (mTBI) in warfighters has increased as a consequence of recent conflicts. This study evaluated the effectiveness of computerized oculomotor vision screening (COVS) in a military population. Oculomotor functions were assessed with COVS and by conventional methods in 20 U.S. military personnel with and 20 without mTBI. The validity of COVS was determined by Pearson correlation and Bland-Altman method ... |
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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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| Materials Testing Capabilities |
07 Dec 2011 |
10 pages |
| Authors:
Mu-Jen Yang; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| The objective of this task is to compile a list of materials testing capabilities suitable for testing the materials development for liquid rocket engines by the JANNAF liquid propulsion community in USA. Information has been collected on the materials testing capabilities in some of the commercial testing laboratories, academic research and development institutes, and government organizations; it has been compiled, and has been listed in Tables I, II and III, ... |
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| Enhancing the Enhanced Scenario-Based Method of Cost Risk Analysis |
Dec 2011 |
51 pages |
| Authors:
Seth T Hooper; NAVAL POSTGRADUATE SCHOOL MONTEREY CA GRADUATE SCHOOL OF BUSINESS AND PUBLIC POLICY
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| The current S-Curve method of cost risk analysis for major Department of the Navy (DON) acquisition projects does not accurately estimate actual cost when the program reaches Full Rate Production. Another sometimes more effective method of measuring cost risk is by using the enhanced scenario-based method (eSBM) of risk analysis. The reason that cost estimations from the milestone B costs are inaccurate is that very little, if any, real information ... |
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| Aerodynamic Analysis of the M33 Projectile Using the CFX Code |
Dec 2011 |
97 pages |
| Authors:
Chee H Wong; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The M33 projectile has been analyzed using the ANSYS CFX code that is based on the numerical solution of the full Navier-Stokes equations. Simulation data were obtained against various Mach numbers ranging from M= 0.5 to M2.6 at 0 and 2 angles of attack. Simulation data were also obtained against various angles of attack from 0 to 85 for M= 0.5. For Mach numbers between M= 0.5 to 2.6, the ... |
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| Aerodynamic Validation of Emerging Projectile Configurations |
Dec 2011 |
103 pages |
| Authors:
Sor W Lun; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Ever-increasing demands for accuracy and range in modern warfare have expedited the optimization of projectile design. The crux of projectile design lies in the understanding of its aerodynamic properties early in the design phase. This research first investigated the aerodynamic properties of a standard M549, 155mm projectile. The transonic speed region was the focus of the research as significant aerodynamic variation occurs within this particular region. Aerodynamic data from wind ... |
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| A Technique for Measurement of Static and Dynamic Longitudinal Aerodynamic Derivatives Using the DSTO Water Tunnel |
Dec 2011 |
47 pages |
| Authors:
Daniel M Newman; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA)
|
| The DSTO water tunnel's balance and rotary support mechanism provides a measurement capability for longitudinal dynamic derivatives. This report documents the underlying theory and computational implementation of a technique which uses the water tunnel for determination of normal force and pitching moment coe cient derivatives with respect to angle of attack, non-dimensional pitch rate and angle of attack rate. |
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| Photonic Applications Using Electrooptic Optical Signal Processors |
16 Nov 2011 |
43 pages |
| Authors:
Harold R Fetterman; CALIFORNIA UNIV OAKLAND
|
| During the contract new designs of electrooptic signal processors were made from nonlinear optical polymers. These systems were based upon the latest lowest loss polymers available and involved a novel system of serial modules. The first implementation of these devices included ring resonators [1], analog-to-digital conversion [2] and single sideband optical links [3]. These are discussed in the paper [4] by Seo on Optical Signal Processor using electrooptic waveguides. One ... |
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| Hybrid Immersion-Polarization Method for Measuring Birefringence Applied to Spider Silks |
15 Oct 2011 |
7 pages |
| Authors:
Douglas J Little; Deborah M Kane; MACQUARIE UNIV SYDNEY (AUSTRALIA)
|
| A technique for accurate measurement of the principle refractive indices and birefringence for silklike samples is presented. It is based on rotating the linear polarization of the illuminating light on a silk immersed in reference liquid to achieve index matching at the silk/liquid interface. The technique was used to measure the principal refractive indices of a P. eburnus radial silk at different strains. This in turn allows the calculation of ... |
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| Fundamental Experimental and Numerical Investigation of Active Control of 3-D Flows |
06 Oct 2011 |
24 pages |
| Authors:
Michael Amitary; Kenneth Jansen; RENSSELAER POLYTECHNIC INST TROY NY
|
| A combined experimental and numerical work was conducted on the interaction between finite span synthetic jets and a 3-D cross-flow. We completed a series of experimental and numerical simulations of the interaction of the synthetic jets with a cross-flow over unswept and swept configurations. The results show that the interaction results in the formation of secondary flow structures that enhance mixing and increase the efficiency of flow control. We publish ... |
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| Tuning Thermal and Electrical Conductivities in Structure-engineered Nanowires for High-efficiency Thermoelectric Devices |
30 Sep 2011 |
21 pages |
| Authors:
Wooyoung Lee; YONSEI UNIV SEOUL (REPUBLIC OF KOREA)
|
| The search for new materials with enhanced thermoelectric properties continues to be of central importance in thermoelectricity. It has been challenging to increase the thermoelectric figure of merit (ZT=S2 sigma T/k) of materials, which determines the efficiency of thermoelectric devices, because the three parameters such as Seebeck coefficient (S) electrical conductivity (sigma), and thermal conductivity (k) of bulk materials are inter-dependent. With the development of nanotechnology, ZT of nano-structured materials ... |
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| A New Orbital Analyst Tool for Associating Un-cataloged Analyst Debris with Historical Launches, Breakups, and Anomalous Events |
Sep 2011 |
12 pages |
| Authors:
Bruce R Bowman; Robin Thurston; Robert Teets; AIR FORCE SPACE COMMAND PETERSON AFB CO
|
| A suite of astrodynamic software tools has been developed for associating un-catalogued analyst satellite debris with historical launches, breakups, and anomalous events. A semi-analytical orbit integrator is at the heart of the tool suite. To associate currently tracked analyst debris with events occurring over 30 to 45 years ago requires an orbit integrator that predicts orbit plane ascending node values accurately, with errors no more than a few degrees over ... |
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| Investigation of Transitional Flows on Compressor Blades in Cascade |
Sep 2011 |
111 pages |
| Authors:
Michael L Holihan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Flow around polished second-generation controlled-diffusion blades in cascade set at their design inlet flow angle was investigated at various Reynolds numbers using static pressure measurements, five-hole probe surveys, twocomponent laser Doppler velocimetry (LDV), computational fluid dynamics and flow visualization. A suction-side separation bubble formed at Reynolds number, based on chord length, of 203,000 and collapsed by a Reynolds number of 393,000. Five-hole probe surveys characterized the blade-row inlet and outlet ... |
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| Wave Propagation in Second-order Nonlinear Piezoelectric Media |
Sep 2011 |
44 pages |
| Authors:
David A Hopkins; George A Gazonas; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Computational results for the response of piezoelectric materials to various excitations are presented. The governing equations are based on a second-order theory of piezoelectricity, which is specialized for the 6mm crystal class. The equations are formulated in a Lagrangian reference configuration. These equations represent the fully coupled nonlinear multiphysics response. Numerical solutions of these equations are first verified using analytical solutions for wave propagation in linear piezoelectric media. The effects ... |
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| Analysis of the 2008 Chinese Earthquake Aftershocks Using Cross-Correlation |
Sep 2011 |
13 pages |
| Authors:
Dmitry I Bobrov; Ivan O Kitov; COMPREHENSIVE NUCLEAR TEST BAN TREATY ORGANIZATION VIENNA (AUSTRIA) PREPARATORY COMMISSION
|
| Our objective is to assess the performance of a cross-correlation technique as applied to automatic and interactive processing of aftershock sequences at the International Data Centre (IDC). This technique allows a flexible approach to time windows, frequency bands, correlation thresholds and other parameters controlling the flux of detections. For array stations, we used vertical channels to calculate a unique cross-correlation coefficient. All detections obtained by cross-correlation were then used to ... |
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| Geoacoustic Inversion in Shallow Water |
Sep 2011 |
7 pages |
| Authors:
N R Chapman; VICTORIA UNIV (BRITISH COLUMBIA) SCHOOL OF EARTH AND OCEAN SCIENCES
|
| LONG TERM GOALS: The ability to predict transmission loss of sound propagating in shallow water is constrained by the knowledge of the geoacoustic properties of the bottom. The long term objectives of this research project are related to the investigation of experimental methods and inversion techniques for estimating parameters of geoacoustic models of the ocean bottom and the associated uncertainties in the model parameter values. The specific goals are to ... |
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| Fast Constant Weight Codeword to Index Converter |
AUG 2011 |
5 pages |
| Authors:
J. T. Butler; T. Sasao; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Constant weight codewords, in which the number of 1's is fixed, are essential to many coding applications. In this paper, we show an efficient circuit that converts a constant weight codeword into a unique index of that codeword. For example, this circuit is necessary when constant weight codewords are used to transmit data on and off chip. Our circuit is based on the combinatorial number system in which the digits ... |
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| Explosively Driven Particle Fields Imaged Using a High-Speed Framing Camera and Particle Image Velocimetry |
Aug 2011 |
36 pages |
| Authors:
Charles M Jenkins; Yasuyuki Horie; Robert C Ripley; William H Wilson; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Metallic particles have been an ingredient in high explosives for decades due to their large energy release upon combustion. A concern over the understanding of metal particle combustion release rates has driven the development of simulation packages for detonation and blast-wave dynamics. The current models for metallic particles are a primary source of error in simulations and require experimental data to adjust them. This effort provided experimental data using two ... |
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| Relationships between Water Attenuation Coefficients Derived from Active and Passive Remote Sensing: A Case Study from Two Coastal Environments |
14 Jun 2011 |
11 pages |
| Authors:
Martin A Montes; James Churnside; ZhongPing Lee; Richard Gould; Robert Arnone; Alan Weidemann; NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| Relationships between the satellite-derived diffuse attenuation coefficient of downwelling irradiance (Kd) and airborne-based vertical attenuation of lidar volume backscattering (a) were examined in two coastal environments. At 1.1 km resolution and a wavelength of 532 run, we found a greater connection between a and Kd when a was computed below 2 m depth (Spearman rank correlation coefficient up to 0.96), and a larger contribution of Kd to a with respect ... |
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| Experimental Study of an Air-Augmented Waterjet Propulsor |
JUN 2011 |
6 pages |
| Authors:
Scott Gowing; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| Compressed air can be added to the flow in a waterjet pump to increase the thrust. The gas bubbles expand as the pump mixture passes through the pressure gradient of the convergent discharge nozzle, imparting energy into the flow. In this experiment, air is injected into a pump fitted to a model boat and static thrust is measured for a range of void fractions using two nozzles. Air is injected ... |
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| Strategic Implications of U.S. Fighter Force Reductions: Air-to-Air Combat Modeling Using Lanchester Equations |
JUN 2011 |
84 pages |
| Authors:
Ronald E. Gilbert; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Lanchester equations are used as the foundation for analysis of air superiority forces, mathematically addressing the impending shortage of the United States fighters; focusing on the role of advanced technology: stealth aircraft, air-to-air missiles, and the rapid proliferation of electronic attack capabilities. These factors are accounted for in determination of the attrition coefficients for heterogeneous fighter aircraft through a simplistic scoring methodology and compared to potential adversarial states. ARENA simulation ... |
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| Statistical Origin of Allometry |
MAY 2011 |
8 pages |
| Authors:
D. West; B. J. West; ARMY RESEARCH OFFICE RESEARCH TRIANGLE PARK NC
|
| The allometry relationship (AR) between two properties of a living network X and Y is X = aY b where one or both of the variables is a measure of size and the allometry coefficient a and exponent b are fit to data. Many investigators have focused on determining the proper value of b entailed by an appropriate biological model, whereas others have argued that the allometry coefficient plays the ... |
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| Numeric Function Generators Using Piecewise Arithmetic Expressions |
MAY 2011 |
7 pages |
| Authors:
Shinobu Nagayama; Tsutomu Sasao; Jon T. Butler; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| This paper proposes new architectures for numeric function generators (NFGs) using piecewise arithmetic expressions. The proposed architectures are programmable, and they realize a wide range of numeric functions. To design an NFG for a given function, we partition the domain of the function into uniform segments, and transform a subfunction in each segment into an arithmetic spectrum. From this arithmetic spectrum, we derive an arithmetic expression, and realize the arithmetic ... |
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| Approximate Global Convergence and Quasi-Reversibility for a Coefficient Inverse Problem with Backscattering Data |
APR 2011 |
44 pages |
| Authors:
Andrey V. Kuzhuget; Larisa Beilina; Michael V. Klibanov; Vladimir G. Romanov; NORTH CAROLINA UNIV AT CHARLOTTE DEPT OF MATHEMATICS AND STATISTICS
|
| A numerical method with the approximate global convergence property is developed for a 3-D Coefficient Inverse Problem for a hyperbolic PDE with the backscattering data. An important part of this technique is the quasi-reversibility method. Approximate global convergence theorem is proven. Results of two numerical experiments are presented. |
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| Ultra-High Sensitive Magnetoelectric Nanocomposites Current Sensors |
30 MAR 2011 |
36 pages |
| Authors:
Shashank Priya; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG OFFICE OF SPONSORED PROGRAMS
|
| We investigated the synthesis and characterization of magnetoelectric (ME) 3-2 nanocomposite thick films using aerosol-deposition (AD). Piezoelectric and magnetostrictive materials were simultaneously deposited on a platinized silicon substrate using AD method and a 13 micron thick nanocomposite film was realized. Upon annealing, magnetostrictive phase was found to form a layered structure inside the piezoelectric matrix. Detailed microstructural analysis revealed the connectivity of individual phases. This nanocomposite thick film was found ... |
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| Inverse Problems for Nonlinear Delay Systems |
15 Mar 2011 |
32 pages |
| Authors:
H T Banks; Keri Rehm; Karyn Sutton; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| We consider inverse or parameter estimation problems for general nonlinear nonautonomous dynamical systems with delays. The parameters may be from a Euclidean set as usual, may be time dependent coefficients or may be probability distributions across a population as arise in aggregate data problems. Theoretical convergence results for finite dimensional approximations to the systems are given. Several examples are used to illustrate the ideas and computational results that demonstrate efficacy ... |
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| Light Propagation through Anisotropic Turbulence |
01 Mar 2011 |
7 pages |
| Authors:
Italo Toselli; Brij Agrawal; Sergio Restaino; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MECHANICAL AND ASTRONAUTICAL ENGINEERING
|
| A wealth of experimental data has shown that atmospheric turbulence can be anisotropic; in this case, a Kolmogorov spectrum does not describe well the atmospheric turbulence statistics. In this paper, we show a quantitative analysis of anisotropic turbulence by using a non-Kolmogorov power spectrum with an anisotropic coefficient. The spectrum we use does not include the inner and outer scales, it is valid only inside the inertial subrange, and it ... |
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| Model Variational Inverse Problems Governed by Partial Differential Equations |
Mar 2011 |
36 pages |
| Authors:
Noei Petra; Georg Stadler; TEXAS UNIV AT AUSTIN INST FOR COMPUTATIONAL ENGINEERING AND SCIENCES
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| We discuss solution methods for inverse problems, in which the unknown parameters are connected to the measurements through a partial differential equation (PDE). Various features that commonly arise in these problems, such as inversions for a coefficient field, for the initial condition in a time-dependent problem, and for source terms are being studied in the context of three model problems. These problems cover distributed, boundary, as well as point measurements, ... |
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| Cyanate Ester Resin Modified with Nano-particles for Inclusion in Continuous Fiber Reinforced Composites |
25 Feb 2011 |
58 pages |
| Authors:
Michael R Kessler; Prashanth Badrinarayanan; IOWA STATE UNIV AMES
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| The mismatch in coefficient of thermal expansion (CTE) between the polymer matrix and low CTE carbon fibers causes development of residual stresses in polymer matrix composites (PMCs) that can lead to micro cracking and failure. This report describes the development of hybrid polymer composites comprising of a unique low viscosity bisphenol E cyanate ester resin (BECy) resin reinforced with macro scale carbon fibers and negative CTE nanoparticles. Polymer nanocomposites were ... |
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| Depletion-Induced Shape and Size Selection of Gold Nanoparticles (Postprint) |
JAN 2011 |
9 pages |
| Authors:
Kyoungweon Park; Hilmar Koerner; Richard A. Vaia; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| For nanoparticle-based technologies, efficient and rapid approaches that yield particles of high purity with a specific shape and size are critical to optimize the nanostructure-dependent optical, electrical, and magnetic properties, and not bias conclusions due to the existence of impurities. Notwithstanding the continual improvement of chemical methods for shaped nanoparticle synthesis, byproducts are inevitable. Separation of these impurities may be achieved, albeit inefficiently, through repeated centrifugation steps only when the ... |
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