| Energetics and Dynamics of the Reactions of O(3P) with Dimethyl Methylphosphonate and Saria |
15-Sep-2009 |
11 pages |
| Authors:
Matthew Braunstein; Patrick F Conforti; James A Dodd; SPECTRAL SCIENCES INC BURLINGTON MA
|
 | Electronic structure and molecular dynamics calculations were performed on the reaction systems O(3P) + sarin and O(3P) + dimethyl methylphosphonate (DMMP), a sarin simulant. Transition state geometries, energies, and heats of reaction for the major reaction pathways were determined at several levels of theory, including AM1, B3LYP/6-311+G(d,p), and CBS-QB3. The major reaction pathways for both systems are similar and include H-atom abstraction, H-atom elimination, and methyl elimination, in rough order ... |
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| Second Generation Organometallic Materials for Non-Linear Optical Application |
26-May-2009 |
18 pages |
| Authors:
Kirk S Schanze; FLORIDA UNIV GAINESVILLE
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| The primary focus of this program was to synthesize pi-conjugated oligomers that feature high cross section two-photon absorbing (TPA) chromophores combined with transition metal centers. The TPA chromophores imbue the oligomers with high cross sections for two-photon absorption, whereas the metal centers provide for efficient production of long-lifetime, strongly absorbing triplet excited states. Because of the strong absorption of the triplet excited states, the materials display reverse saturable absorption (RSA). ... |
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| Classical Collision Spectrum of O + CO (Preprint) |
07-Apr-2009 |
21 pages |
| Authors:
M Braunstein; J W Duff; SPECTRAL SCIENCES INC BURLINGTON MA
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| The work of Noid et al. [J. Chem. Phys., 67, 404 (1977)] has shown that sharp molecular spectra can be obtained through a Fourier transform of the autocorrelation function of a classical trajectory. In the present work, we extend this idea to obtain a spectrum by Fourier transform of the dipole moment function of collision product trajectories. We show that this classical collision spectrum (CCS) is related to the cross ... |
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| Anisotropy of the Hot Plastic Deformation of Ti-6Al-4V Single-Colony Samples (Preprint) |
Apr-2009 |
26 pages |
| Authors:
S L Semiatin; A A Salem; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| The critical resolved shear stresses and flow curves for the seven possible slip systems in Ti-6Al-4V with a lamellar microstructure were determined via high temperature uniaxial compression testing. For this purpose, samples with a rectangular cross section were cut from single colonies grown using a float-zone technique and then tested at 815 degrees C. Each sample was oriented for single slip along one of seven different slip systems in the ... |
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| Wave Optics Simulation of Optically Augmented Retroreflections for Mononstatic/Bistatic Detection |
Mar-2009 |
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| Authors:
Tatar; John J III; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
 | Optical devices interrogated with a laser in the appropriate band can exhibit strong, deterministic reflections of the incident beam. This characteristic could be exploited for optical target detection and identification. The distribution of reflected power is strongly dependent on the geometry of the interrogation scenario, atmospheric conditions, and the cross section of the target optical device. Previous work on laser interrogation systems in this area has focused on analytic models ... |
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| A Theoretical Model Analysis of Absorption of a Three level Diode Pumped Alkali Laser |
Mar-2009 |
116 pages |
| Authors:
Lewis; Charlton D II; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This paper models the absorption phenomena of light in a three level diode pumped alkali laser system. Specifically this model calculates for a user defined set of system parameters the attenuation of the input pump beam and characteristics of the bleached wave. Using Wolfram's Mathematical 6.0 software all necessary physics for an accurate description of absorption was modeled from first principles: energy levels, cross sections, spin-orbit kinetic processes, saturation frequencies, ... |
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| Enhanced Mass Transport in Ultrarapidly Heated Ni/Si Thin-Film Multilayers |
Jan-2009 |
7 pages |
| Authors:
L P Cook; W F Egelhodd; C B Montgomery; C E Campbell; U R Kattner; I Levin; W Wong-Ng; S Eustis; N Bassim; R E Cavicchi; M D Vaudin; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
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| We investigated multilayer and bilayer Ni/Si thin films by nanodifferential scanning calorimetry nano-DSC at ultrarapid scan rates, in a temperature-time regime not accessible with conventional apparatus. DSC experiments were completed at slower scan rates as well, where it was possible to conduct parallel rapid thermal annealing experiments for comparison. Post experimental characterization was accomplished by x-ray diffraction, and by transmission electron microscopy TEM and energy-filtered TEM of thin cross sections ... |
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| Evaluation of Minimum Asphalt Concrete Thickness Criteria |
Oct-2008 |
112 pages |
| Authors:
Haley P Bell; L W Mason; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
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| Personnel of the U.S. Army Engineer Research and Development Center (ERDC) were tasked by Headquarters, Air Combat Command, to evaluate the Department of Defense's (DoD) minimum asphalt concrete thickness criteria outlined in United Facilities Criteria 3-260-02. Recent improvements to the DoD's flexible pavement design procedure and a renewed emphasis on the design and construction of contingency pavements had prompted concerns regarding the design and evaluation of thin asphalt concrete pavements. ... |
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| Hypermixer Pylon Fuel Injection for Scramjet Combustors |
11-Sep-2008 |
188 pages |
| Authors:
Jason C Doster; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| Fueling the core airflow of a circular or elliptical scramjet combustor cross-section often requires intrusive geometries. Intrusive geometries can distribute the fuel evenly across the combustor cross-section and act as a flameholder for the fuel/air mixture. Compared to conventional transverse or angled wall injection, intrusive geometries allow easier penetration into the core combustor airflow and reduced fuel injection pressures. The design and testing of an intrusive pylon geometry for scramjet ... |
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| Performance Piezoelectric Airframes for Nano Air Vehicles |
30-Jun-2008 |
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| Authors:
H Kommepalli; A Hirsh; C Rahn; S Tadigadapa; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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| Currently, Unmanned Air Vehicles (UAVs) are too large to penetrate buildings for situational awareness and reconnaissance, emplace important sensors, and sample and return material. While a variety of Micro Air Vehicles have been built and flown that use propellers and flapping wings for lift generation, Nano Air Vehicles (NAVs), defined as weighing less than 10 grams with wingspans less than 7.5 cm, have yet to be flown. NAV-scale actuators and ... |
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| Quenching Dynamics of Electronically Excited Hydroxyl Radicals |
19 MAY 2008 |
6 pages |
| Authors:
Marsha I. Lester; PENNSYLVANIA UNIV PHILADELPHIA
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| Collisional quenching of electronically excited OH radicals by molecular partners has been investigated over the past 25 years, principally by evaluating the quenching cross sections for partners of aeronautical, atmospheric, and/or combustion relevance. Yet little is known about the outcome of these electronic quenching events, except that they facilitate the efficient removal of OH from the excited Alpha 2sigma+ electronic state by introducing nonradiative decay pathways. Most recently, we carried ... |
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| Morphologic Examination of the Stability of Pass Cavallo, Texas |
01-May-2008 |
48 pages |
| Authors:
Nicholas C Kraus; Brian K Batten; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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| The study concerns the cross-sectional area stability of Pass Cavallo, a natural coastal inlet located in the southwest corner of Matagorda Bay, Texas. The width of Pass Cavallo has decreased since opening of the Matagorda Ship Channel (MSC) entrance to Matagorda Bay in 1966. The process of narrowing began after separation of Matagorda Bay into East Matagorda Bay and the present Matagorda Bay by formation of the Colorado River delta ... |
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| Modeling the SAR Signature of Nonlinear Internal Waves |
APR 2008 |
17 pages |
| Authors:
Ellen E. Lettvin; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
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| Nonlinear Internal Waves are pervasive globally, particularly in coastal waters. The currents and displacements associated with internal waves influence acoustic propagation and underwater navigation, as well as ocean transport and mixing. Synthetic Aperture Radar (SAR) imagery can reveal the surface manifestations of internal waves (IWs) in satellite imagery and so is routinely used to locate and characterize these features. Though some of the mechanisms that link the SAR signatures, surface ... |
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| Numerical Investigation of Transition in Supersonic Boundary Layers Using DNS and LES |
31 MAR 2008 |
232 pages |
| Authors:
Hermann F. Fasel; Frank Husmeier; Christian S. Mayer; ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
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| This work focuses on instability mechanisms of high-speed boundary layers over flat plates and cones with a circular cross section. Supersonic transition investigations at Mach 2 and hypersonic transition investigations at Mach 8 are performed using Direct Numerical Simulations (DNS). At wind-tunnel conditions, these simulations allow for comparison with experimental measurements to verify fundamental stability characteristics. For the DNS of boundary-layer transition at Mach 2, the experimental studies by Kosinov ... |
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| Contrast Enhancement for Thermal Acoustic Breast Cancer Imaging via Resonant Stimulation |
01-Mar-2008 |
30 pages |
| Authors:
Jian Li; Mark Sheplak; Lou Cattafesta; Henry Zmuda; Huabei Jiang; Manuel Arreola; FLORIDA UNIV GAINESVILLE
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| This research plans to develop enhanced contrast thermal acoustic imaging (TAI) technology for the detection of breast cancer by combining amplitude-modulated (AM) electromagnetic (EM) field excitation resonant acoustic scattering and advanced signal processing techniques. While EM-induced TAI possesses great promise, the thermal acoustic signals tend to be weak However when the tumor is excited into resonance via EM stimulation the effective acoustic scattering cross-section may increase by a factor in ... |
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| Collection Efficiencies of Various Airborne Spray Flux Samplers Used in Aerial Application Research |
Jan-2008 |
11 pages |
| Authors:
W C Hoffmann; Bradley K Fritz; AGRICULTURAL RESEARCH SERVICE COLLEGE STATION TX
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| A low air speed, spray dispersion tunnel was constructed and used to evaluate the collection efficiency of passive spray flux collectors. The dispersion tunnel utilizes an air-assisted nozzle to generate a spray cloud with a D(sub V0.5) of 18.5 (+/-0.4)micrometers at air speeds ranging from 0.4-4.0 m/s. A sampling protocol was developed to minimize spray flux and air speed variation effects while providing a check on theoretical collection efficiency calculations. ... |
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| Analysis of the Oklahoma City Air Logistics Center's (ALC) Contract Management Processes |
DEC 2007 |
111 pages |
| Authors:
Andrew Nordin; Bennet Burton; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This paper assesses the process capabilities and competencies of Air Force Material Command's (AFMC) Air Logistics Center (ALC) at Tinker AFB, OK. The assessment uses a cross-sectional questionnaire covering contracting processes and procedures. The purpose of this study is to analyze the ALCs contracting processes and procedures to better establish a baseline for contract management maturity. Using the Contract Management Maturity Model (CMMM) and its assessment tool, this model will ... |
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| Measurement of Non-Linear Internal Waves and Their Interaction with Surface Waves Using Coherent Real Aperture Radars |
SEP 2007 |
9 pages |
| Authors:
William J. Plant; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| The objectives of the grant were to use a coherent real aperture radar to 1) study the interaction of surface waves with internal wave, the process that is responsible for the synthetic aperture radar (SAR) imagery of internal waves; 2) Determine the extent to which Doppler velocity modulations observed by coherent radars, including along-track interferometric SARs, are faithful representations of surface currents generated by internal waves; and 3) track the ... |
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| Geologic Conceptual Model of Mosul Dam |
SEP 2007 |
61 pages |
| Authors:
Lillian D. Wakeley; Julie R. Kelley; Cary A. Talbot; Monte L. Pearson; Seth W. Broadfoot; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
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| Mosul Dam, Iraq, was built in the 1980s on a foundation of soluble geologic materials. Because of the solubility of its foundation and abutments, maintenance grouting began immediately after construction and continues to the present. The U.S. Army is concerned about the stability of the dam, and about the potential military and political impacts that would accompany dam failure. At the request of the U.S. Army Corps of Engineers Gulf ... |
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| Laboratory Study of Wind Effect on Runup over Fringing Reefs. Report 1. Data Report |
JUL 2007 |
83 pages |
| Authors:
Zeki Demirbilek; Okey G. Nwogu; Donald L. Ward; ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
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| The report describes experimental data obtained from a wind-wave flume study conducted August-September 2006 at the University of Michigan in Ann Arbor, MI. The study objectives were two-fold: to quantify wind effects on wave runup on fringing reefs of the Pacific Island of Guam and to obtain detailed wave data along a complex reef system consisting of steep slopes and shallow areas for validating wave breaking, dissipation, wave setup and ... |
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| Two-Photon Absorption Measurements: Establishing Reference Standards. |
08 JUN 2007 |
19 pages |
| Authors:
Marek Samoc; Anna Samoc; Paul A. Fleitz; AUSTRALIAN NATIONAL UNIV CANBERRA
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| Two-Photon Absorption "TPA" is an important phenomenon taking place at high light intensities and consisting in simultaneous absorption of two low energy photons to generate a higher energy excited state of a material. Materials showing efficient two-photon absorption are required for a number of applications including information storage, photonic signal processing, optical power limiting, nonlinear microscopy of biological systems etc. This report contributes to the knowledge of parameters influencing the ... |
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| Accurate Evaluation of Nonlinear Absorption Coefficients in InAs, InSb and HbCdTe Alloys (Postprint) |
06 JUN 2007 |
15 pages |
| Authors:
Shekhar Guha; Zhi G. Yu; SRINIVASAN KRISHNAMURTHY; Leonel P. Gonzales; SRI INTERNATIONAL MENLO PARK CA
|
| We present a full band structure calculation of temperature- and wavelength-dependent two-photon absorption (TPA) coefficients and free carrier absorption (FCA) cross sections in InAs, InSb, and Hg1−xCdxTe alloys. Although the wavelength dependence of the TPA coefficients agrees well with Wherrett expression, the accurately calculated values are smaller by a factor of 1.2 to 2.5. In addition, the TPA coefficient depends sensitively on the photoexcited carrier density in small gap material. ... |
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| Modeling of High-Frequency Acoustic Propagation in Shallow Water |
JUN 2007 |
150 pages |
| Authors:
Juan C. Torres; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| This research involves numerical modeling of acoustic signals through shallow water channels. The sound is computationally modeled in a vertical plane as a dense fan of beams radiating from the transmitter location. The cross section of each 2-dimensional beam is represented as a Gaussian distribution of acoustic energy. The Gaussian beam travels axially along rays governed by Snell's Law, dispersing in width as a function of travel distance. At arbitrary ... |
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| Ohmic Contacts for Technology for Frequency Agile Digitally Synthesized Transmitters |
21 MAY 2007 |
6 pages |
| Authors:
Suzanne E. Mohney; PENNSYLVANIA STATE UNIV UNIVERSITY PARK OFFICE OF SPONSORED PROGRAMS
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| Ohmic contacts to InAs and InGaAs have been investigated with the objective of providing low contact resistance, good thermal stability, and process compatibility for scaling lnP-based heterojunction bipolar transistors to smaller sizes. For p-type InAs, the combination of modest contact resistance and good thermal stability at 250 0 C was achieved with metallizations that had thin Pd layers deposited first, fol lowed by W or Ti/Pt barrier layers, then Au. ... |
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| An Examination of Acceptable Navigation Accuracy for LISA Orbits |
04 MAY 2007 |
60 pages |
| Authors:
Reid W. Smythe; NAVAL ACADEMY ANNAPOLIS MD
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| This project assessed the accuracy with which a formation of satellites, the Laser Interferometer Space Antenna (LISA), must be placed into orbit. The LISA formation will consist of three satellites orbiting the Sun, forming an equilateral triangle. The first phase dealt with the formation parameters (leg length, leg length time rate of change, interior leg angle, and formation-sun-earth angle) as a function of time. Duplication of plots contained in other ... |
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| Platinum Acetylide Two-Photon Chromophores (Preprint) |
APR 2007 |
62 pages |
| Authors:
Aaron R. Burke; Thomas M. Cooper; Joy E. Rogers; Jonathan E. Slagle; Douglas M. Krein; Benjamin C. Hall; Albert Fratini; Daniel G. McLean; UNIVERSAL ENERGY SYSTEMS INC DAYTON OH HUMAN FACTORS DIV
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| To explore the photophysics of platinum acetylide chromopores having strong two photon cross section, we have investigated the synthesis and spectroscopic characterization of a series of platinum acetylide complexes that feature highly π-conjugated ligands substituted with π-donor or ?acceptor moieties. The molecules (numbered 1-4) considered in the present work are NLO-functionalized analogs of bis(phenylethynyl)bis(bributylphosphine)platinum(II) complexes. Molecule 1 carries two benzothiazolylfluorene and molecule 2 carries two diphenylaminofluorene substituents bound to the ... |
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| Time-Resolved and Spectroscopic Three-Dimensional Optical Breast Tomography |
APR 2007 |
36 pages |
| Authors:
Robert R. Alfano; STATE UNIV OF NEW YORK
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| The research carried out during the current reporting period included: (a) Use of optical tomographic imaging using independent component analysis (OPTICA) developed during the first reporting period to image targets in ex vivo breast tissue specimens, (b) Extension of OPTICA for obtaining cross sectional image of targets in turbid media, (c) (d) Development of a forward model for scattered light intensity distribution in the backscattering geometry; and (e) Development of ... |
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| Quantifying the Effect Of Fuselage Cross-Sectional Shape on Structural Weight (PREPRINT) |
MAR 2007 |
22 pages |
| Authors:
Michael A. Falugi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH ADVANCED STRUCTURAL CONCEPTS BRANCH
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| Analytical trade studies were set up and are being performed to quantify the effect of fuselage cross-sectional shape on structural weight for a cargo transport aircraft. The target vehicle design reflects various geometry, aerodynamic and inertia loads, internal pressurization, and other requirements associated with a medium-sized military transport configuration. Several elliptical cross-sections and at least one cross section containing one or more flat (LO-friendly) outer mold line segments are being ... |
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| Accurate Evaluation Nonlinear Absorption Coefficients for Light Propagation in InAs, InSb, and HgCdTe Alloys (Preprint) |
JAN 2007 |
32 pages |
| Authors:
Srini Krishnamurthy; Zhi G. Yu; Leo Gonzalez; Shekhar Guha; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| We present a full-bandstructure calculation of temperature- and wavelength-dependent two-photon absorption (TPA) coefficients and free-carrier absorption (FCA) cross sections in InAs, InSb, Hg1-xCdxTe alloys. Although the wavelength dependence of the TPA coefficients agrees well with widely used analytical expression, our calculated values are smaller by a factor of 1.2 to 2.5. In addition, the TPA coefficient depends sensitively on the photoexcited carrier density in small gap materials. The FCA is ... |
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| Effects of Conjugation in Length and Dimension on Two-Photon Properties of Fluorene-Based Chromophores (Preprint) |
JAN 2007 |
21 pages |
| Authors:
Ruth Pachter; Kiet A. Nguyen; Paul N. Day; Ramamurthi Kannan; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| We report the computed two-photon (TPA) absorption spectra based upon the results obtained from quadratic response time-dependent density functional theory for fluorine-based donor-pi-acceptor molecules. Coulomb attenuated functionals with a long-range exchange contribution are applied to predict TPA excitation energies and cross sections and to account for the observed spectral anomalies. The effects of conjugation and multibranching on the TPA spectra are discussed. |
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| Effects of Solvation on One- and Two-Photon Spectra of Coumarin Derivatives: A Time-Dependent Density Functional Theory Study (Postprint) |
2007 |
13 pages |
| Authors:
Ruth Pachter; Kiet A. Nguyen; Paul N. Day; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| We report one- and two-photon absorption excitation energies and cross sections for a series of 7-aminocoumarins using time-dependent density functional theory with various basis sets and functionals, including exchange-correlation functionals using the Coulomb-attenuating method, to evaluate their performance in the gas phase and in solvents. Except for the results of one functional, the computed one-photon excitation energies and transition dipole moments are in good agreement with experiment. The range of ... |
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| Effects of Solvation On One- and Two-Photon Spectra of Coumarin Derivatives: A TDDFT Study (Preprint) |
OCT 2006 |
36 pages |
| Authors:
Kiet A. Nguyen; Paul N. Day; Ruth Pachter; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SURVIVABILITY AND SENSOR MATERIALS DIV/HARDENED MATERIALS
|
| We report one- (OPA) and two-photon absorption (TPA) excitation energies and cross sections for a series of 7-aminocoumarins using time-dependent density functional theory with various basis sets and functionals, including exchange-correlation functionals using the Coulomb-attenuating method (CAMB3LYP and mCAMB3LYP), to evaluate their performance in gas-phase and in solvents. Except for the CAMB3LYP results , the computed OPA excitation energies and transition dipole moments are in good agreement with experiment. The ... |
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| Two-Photon Porphyrin Core Dendrimers for Optical Power Limiting |
30-Sep-2006 |
18 pages |
| Authors:
Aleksander Rebane; MONTANA STATE UNIV BOZEMAN DEPT OF PHYSICS
|
| This research is to establish novel nonlinear-absorbing materials with large intrinsic two-photon cross section for fast response optical power limiting in the photon wavelength range 700 - 900nm. We synthesize novel porphyrin core dendrimers, which combine the large 2PA efficiency of conjugated dendrites with the high efficiency of excited state absorption of the core tetrapyrrole. The goal of this project is to (a) establish structure property relationships for the novel ... |
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| Application of the SAM Computer Program for Truckee River Stable Channel Analysis |
SEP 2006 |
15 pages |
| Authors:
Stephen H. Scott; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
|
| The purpose of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to demonstrate the utility of the SAM computer programs for evaluating the stability of a stream restoration design on the Truckee River. SAM is an integrated system of computer programs developed under the Flood Damage Reduction and Stream Restoration Research Program sponsored by the U.S. Army Corps of Engineers (USACE 2000). These programs are designed to satisfy the ... |
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| Structurally Efficient Anisotropic Organized Reticulated structures for Cooling of Electronics and Sensors |
31 AUG 2006 |
112 pages |
| Authors:
Richard A. Wirtz; Yanyao Jiang; NEVADA UNIV RENO DEPT OF MECHANICAL ENGINEERING
|
| Anisotropic Organized Reticulated-Filament Structures (AORS), consisting of group- interconnected and purposely oriented thermally conductive filaments, can be configured to have wide ranging porosity and a large specific surface area. When deployed as heat exchanger matrices, these structures produce high ntu-values (number of transfer units) because of the large specific surface area inherent to the media. Examples of structures with the above described characteristics are: laminations of orthogonal-weave fine-wire screen, three-filament ... |
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| Study of Properties of the Microwave Streamer Discharge in a High-Speed Flow of Gas and in Two-Phase Medium |
01 AUG 2006 |
102 pages |
| Authors:
Kirill V. Khodataev; FEDERAL STATE UNITARY FIRM MOSCOW RADIO-TECHNICAL INST (RUSSIA)
|
| This report results from a contract tasking Federal State Unitary Firm 'MRTI' of RAS as follows: The contractor will investigate the use of undercritical streamer microwave discharges for ignition of fuel-air mixtures. The system of microwave radiation initiated spark filaments can uniformly fill a volume with streamers of several thousand degrees Kelvin. Thus, quick ignition of fuel-air mixtures over the whole cross-section of the discharge is anticipated. Experimental and theoretical ... |
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| Development of Novel Two-Photon Absorbing Chromophores |
AUG 2006 |
15 pages |
| Authors:
Thomas M. Cooper; James Heinrichs; Loon-Seng Tan; Augustine M. Urbas; Paul A. Fleitz; Joy E. Rogers; Jonathan E. Slagle; Daniel G. McLean; Richard L. Sutherland; Mark Brant; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| There has been much interest in the development of two-photon absorbing materials and many efforts to understand the nonlinear absorption properties of these dyes, but this area is still not well understood. A computational model has been developed in our lab to understand the nanosecond nonlinear absorption properties that incorporate all of the measured one-photon photophysical parameters of a class of materials called AFX. We have investigated the nonlinear and ... |
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| Effects of Conjugation in Length and Dimension on Spectroscopic Properties of Fluorene-Based Chromophores from Experiment and Theory (Preprint) |
JUL 2006 |
38 pages |
| Authors:
Loon-Seng Tao; Paul A. Fleitz; Ruth Pachter; Kiet A. Nguyen; Joy E. Rogers; Jonathan E. Slagle; Paul N. Day; Ramamurthi Kannan; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SURVIVABILITY AND SENSOR MATERIALS DIV/HARDENED MATERIALS
|
| A series of one-photon (OPA) absorption spectra for fluorine-based donor pi acceptor molecules is presented and spectroscopically assigned, based upon the results obtained from time-dependent density functional theory (TDDFT). The computed excitation energies were generally shown to be in good agreement with experiment, particularly when compared to results from measurements carried out in a nonpolar solvent, which were available for some molecules. The computed oscillator strengths may resolve discordant experimental ... |
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| Research on Nitride Thin Films, Advanced Plasma Diagnostics, and Charged-Particle Processes |
JUL 2006 |
130 pages |
| Authors:
William C. Lanter; Wei Guo; Charles Q. Jiao; David C. Ingram; INNOVATIVE SCIENTIFIC SOLUTIONS INC DAYTON OH
|
| This program has three sub-tasks: 1) Nitride Thin-Film Coatings, 2) Advanced Plasma Diagnostics, and 3) Studies of Charged-Particle Processes. The focus of Task 1 has been to develop amorphous carbon-nitride films utilizing controlled plasma-generated ions to increase the nitrogen concentration within the film. It is anticipated that development of films with higher concentrations of nitrogen will lead to properties similar to those theoretically calculated for crystalline β-C3N4. Successful development of ... |
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| O+HCI Cross Sections and Reaction Probabilities in DSMC |
28 JUN 2006 |
7 pages |
| Authors:
Takashi Ozawa; D. A. Levin; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A chemical reaction model, suitable for use in the Direct Simulation Monte Carlo (DSMC) method, is developed to simulate hypervelocity collisions of an important reaction in atmospheric-jet interactions ? O(3P)+HCI(1Σ+) → OH(2Π)+C1(2P). The model utilizes the Quasi-Classical Trajectory (QCT) method with two potential energy surfaces (PES), new benchmark triple A″ and A′ surfaces [1] and London-Eyring-Polanyi-Sato (LEPS) PES.[2] The sensitivity of the flow to the fidelity of the chemical model ... |
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| Part I - Effects of Diameter on Active Noise Control in Rectangular and Round Ducts |
MAY 2006 |
29 pages |
| Authors:
Jeremy M. Slagley; Steven E. Guffey; WEST VIRGINIA UNIV MORGANTOWN DEPT OF INDUSTRIAL ENGINEERING
|
| Active noise control (ANC) is particularly useful in hard-walled ducts where plane waves propagate. Higher order mode waves are much more difficult to control. Basic acoustic principles dictate that tile cut-on frequency at which higher order modes will first begin to eclipse simple plane waves in a duct will be determined by the cross-sectional diameter of the duct. The lowest frequency for higher order modes will increase as duct diameter ... |
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| Silver Diffusion and High-Temperature Lubrication Mechanisms of YSZ-Ag-Mo Based Nanocomposite Coatings (Preprint) |
MAY 2006 |
43 pages |
| Authors:
J. J. Hu; C. Muratore; A. A. Voevodin; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| Yttria-stabilized zirconia (YSZ) nanocomposite coatings consisting of silver and molybdenum were produced by a hybrid process of filtered vacuum arc, magnetron sputtering and pulsed laser depositions for tribological investigations at different high temperatures. The microstructure of the coatings was determined by X-ray diffraction and transmission electron microscopy. The friction coefficients were measured using a high-temperature ball-on-disk tribometer at 25 to 700C. The coatings with 24 at.% Ag and 10 at.% ... |
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| Part II - Effects of Cross-Sectional Partitioning on Active Noise Control in Round Ducts |
MAY 2006 |
37 pages |
| Authors:
Jeremy M. Slagley; Steven E. Guffey; WEST VIRGINIA UNIV MORGANTOWN DEPT OF INDUSTRIAL ENGINEERING
|
| Active noise control (ANC) is particularly useful in hard-walled ducts where plane waves propagate. Higher order mode waves are much more difficult to control Basic acoustic principles dictate that the cut-on frequency at which higher order modes will first begin to eclipse simple plane waves in a duct will be determined by the cross-sectional diameter of the duct. The lowest frequency for higher order modes will increase as duct diameter ... |
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| Effects of Diameter And Cross-Sectional Partitioning on Active Noise Control in Round Ducts |
14 APR 2006 |
87 pages |
| Authors:
Jeremy M. Slagley; WEST VIRGINIA UNIV MORGANTOWN COLL OF ENGINEERING AND MINERAL RESOURCES
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| Active noise control (ANC) is particularly useful in hard-walled ducts where plane waves propagate. Higher order mode waves are much more difficult to control. Basic acoustic principles dictate that the cut-on frequency at which higher order modes will first begin to eclipse simple plane waves in a duct will be determined by the cross-sectional diameter of the duct. The lowest frequency for higher order modes will increase as diameter decreases. ... |
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| A Preparation Technique for Microscopy Samples of Mechanically Alloyed Nickel-Coated Aluminum Powders |
APR 2006 |
15 pages |
| Authors:
George T. Dewing; Franklyn R. Kellogg; Bradley R. Klotz; Laszlo J. Kecskes; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| A method for the preparation of fine powders for microscopic examination of their cross section is described. Heavily worked nickel-coated aluminum powders were mounted in epoxy and polished to a mirror finish to allow for the characterization of their interior structure. The method presented would be applicable to all types of finely divided media. |
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| Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) Nanorods Superlattice (SL) |
29 MAR 2006 |
16 pages |
| Authors:
Tea W. Kang; DONGGUK UNIV SEOUL (KOREA)
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| The growth condition, electrical, and optical properties of GaN nanorods grown on Si(111) substrates are investigated. The GaN nanorods were grown with a different growth time by using rf-plasma assisted molecular-beam epitaxy. It is clearly demonstrated that the critical diameter for defects-free GaN nanorods is determined to be below ~140 nm under the N-rich condition. Magnesium-doped GaN nanorods were also grown with the same growth condition. Two emission lines corresponding ... |
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| The Chemical Dynamics of Highly Vibrationally Excited Diatomic Ions of Aerospace Relevance |
28 MAR 2006 |
8 pages |
| Authors:
Cheuk-Yiu Ng; Rainer Dressler; CALIFORNIA UNIV DAVIS DEPT OF CHEMISTRY
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| During this funding period, we have completed the PFI-PESICO measurements of the state-selected proton transfer reaction H2+(v+=0-15, N+=1) + He(Ne) -> HeH+ (NeH+) + H. The results of this experiment, together with the cross sections obtained by quasi-classical trajectory (QCT) calculations on this reaction system has been published in the Journal of Chemical Physics (JCP). In a separate theoretical study, which has also been published in JCP, we have performed ... |
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| Hierarchical Modeling of Ferromagnetic SMAs and Composites |
20 JAN 2006 |
64 pages |
| Authors:
Minoru Taya; Masahiro Kusaka; Suhasini Gururaja; WASHINGTON UNIV SEATTLE CENTER FOR INTELLIGENT MATERIALS AND SYSTEMS
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| Ferromagnetic shape memory alloys (FSMA) are key active materials for fast responsive airborne actuators, but the processing cost is rather expensive. If the hybrid actuation mechanism proposed by Taya is used, we can design cost-effective FSMA composite. This report discusses the design guide for FSMA composites, focusing on several types of actuator, (1) laminated composite plate for bending actuators, and (2) helical spring with optimized cross section for axial actuators. ... |
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| O+HCl Chemistry Models for Hypervelocity Collisions in DSMC |
09 JAN 2006 |
19 pages |
| Authors:
T. Ozawa; D. A. Levin; I. J. Wysong; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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| In earlier work, atmospheric-jet interaction flows were simulated using direct simulation Monte Carlo (DSMC) calculations for altitudes of 80, 120 and 160 km. At high altitudes, the O+HCl yields OH+Cl reaction was found to contribute the most to OH production. However, the total collision energy (TCE) reaction probability was often found to be unphysically greater than unity. In this work, we examine in detail different reaction models such as the ... |
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| Hierarchical Modeling of Ferromagnetic SMAs and Composites |
JAN 2006 |
64 pages |
| Authors:
Minoru Taya; Masahiro Kusaka; Suhasini Gururaja; WASHINGTON UNIV SEATTLE DEPT OF MECHANICAL ENGINEERING
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| Ferromagnetic shape memory alloys (FSMA) are key active materials for fast responsive airborne actuators, but the processing cost is rather expensive. IF the hybrid actuation mechanism proposed by Taya is used, we can design cost-effective FSMA composite. This report discusses the design guide for FSMA composites, focusing on several types of actuator, (1) laminated composite plate for bending actuators, and (2) helical spring with optimized cross section for axial actuators. ... |
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