| Investigation into Contact Resistance And Damage of Metal Contacts Used in RF-MEMS Switches |
Sep-2009 |
578 pages |
| Authors:
Kevin W Gilbert; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
 | This research examines the physical and electrical processes involved in lifecycle failure of Microelectromechanical (MEMS) Radio-Frequency (RF) cantilever beam ohmic contact switches. Failures of these switches generally occur at the contact, but complete details of performance of microcontacts are difficult to measure and have not been previously reported. This study investigated the mechanics of microcontact behavior by designing and constructing a novel experimental setup. Three representative contact materials of varying ... |
|
| Zero Dimensional Model of High-Pressure Ablative Capillary Discharge with Capillary Wall Thermal Conduction and Radiation Absorption |
Jun-2009 |
15 pages |
| Authors:
L Pekker; O Pekker; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A zero-dimensional time-dependent high-pressure slab capillary discharge model with capillary wall thermal conduction and wall radiation absorption is presented. The model includes a resistor-inductor-capacitor circuit and a heat-transfer radiation model based on radiation database constructed using PrismSPEC, a commercially available radiation software, to calculate the radiation heat flux output from a uniform plasma slab. The model also includes a model of the thin transition boundary layer between the uniform plasma ... |
|
| Moisture-Induced Delayed Alumina Scale Spallation on a Ni(Pt)Al Coating (Preprint) |
Apr-2009 |
32 pages |
| Authors:
James L Smialek; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| Delayed scale failure was examined for samples of a Ni(Pt)Al-coated CMSX4 single crystal superalloy, cyclically oxidized at 1150 degrees C for 2000 hr. One sample exhibited accentuated coating grain boundary wrinkling, initiating local alumina scale spallation to bare metal, resulting in a final weight loss of 3.3 milligrams/(square centimeter). Spallation under ambient conditions was monitored with time after cooldown and was found to continue for times up to 24 hr, ... |
|
| Estimating Neutral Atmosphere Drivers using a Physical Model |
30-Mar-2009 |
9 pages |
| Authors:
Tim Fuller-Rowell; Cliff Minter; Mihail Codrescu; Mariangel Fedrizzi; COLORADO UNIV AT BOULDER
|
| In the initial phase of this study, research focused on implementing a physical model into an ensemble Kalman filter to estimate the location and magnitude of the upper atmospheric heating. Since the neutral atmosphere is strongly externally driven during geomagnetic storms, specifying the upper atmospheric heating is necessary when describing the time-dependent evolution of the neutral density. Challenges arise when only a portion of the upper atmosphere is observable. Because ... |
|
| A Wigner Distribution Analysis of One Dimensional Scattering |
Mar-2009 |
87 pages |
| Authors:
Brent R Lacy; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| We applied the Wigner Distribution Function, a distribution function of time and frequency based on an initial function of either of those variables, to a series of time based correlation functions. These time based correlation functions were the result of a 1-dimensional free particle wave packet, the reactant wave function, which had propagated through a quantum potential well and then had components of the reactant wave function that exited the ... |
|
| Development of Implicit Compact Methods for Chemically Reacting Flows |
28-Feb-2009 |
56 pages |
| Authors:
Mitchell D Smooke; Marshall Long; YALE UNIV NEW HAVEN CT DEPT OF MECHANICAL ENGINEERING
|
| This project has focused on the design of numerical algorithms that are well suited to the computation of time-dependent chemically reacting flows with finite-rate kinetics and detailed transport. High order compact finite differences have been used to discretize the spatial operators since the spectral-like resolution of the small scales makes it feasible to conduct accurate, long-time computations of multi-dimensional flames burning real fuels. In view of the stiffness of the ... |
|
| Three-Dimensional Diffusion Simulation of Outer Radiation Belt Electrons During the 9 October 1990 Magnetic Storm |
Jan-2009 |
22 pages |
| Authors:
J M Albert; Nigel P Meredith; Richard B Horne; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| Relativistic (l MeV) electron flux increases in the Earth's radiation belts are significantly underestimated by models that only include transport and loss processes, suggesting that some additional acceleration process is required. Here we use a new, threedimensional code that includes radial diffusion and quasi-linear pitch angle and energy diffusion due to chorus waves, including cross terms, to simulate the 9 October 1990 magnetic storm. The diffusion coefficients are activity dependent, ... |
|
| Preliminary Global Radiation Belt Formation and Prediction Model |
25-Jun-2008 |
28 pages |
| Authors:
Michael J Keskinen; NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
|
| A computational model for the time-dependent dynamics of the electron and ion terrestrial radiation belts has been developed. The model solves the fundamental bounce-averaged electron and ion modified Boltzmann Fokker-Planck equations for energy, pitch angle, and L-shell. The code has been applied to broadband whistler turbulence and found to be consistent with empirical models of radiation belt dynamics. |
|
| A Logic for Reasoning About Time-Dependent Access Control Policies |
20-May-2008 |
79 pages |
| Authors:
Henry DeYoung; CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
|
| Allowing access to resources, including data and hardware, without compromising their security is a fundamental challenge in computer science. Because of the number and complexity of authorization policies in access control systems, it is clear that ad hoc methods for specifying and enforcing policies cannot inspire a high degree of trust. Authorization logics have been proposed as a theoretically sound alternative. However, for an authorization logic to be useful in ... |
|
| Realizing the Army Net-Centric Data Strategy (ANCDS) in a Service Oriented Architecture (SOA) |
20-May-2008 |
19 pages |
| Authors:
James Blalock; Michelle Dirner; Eric Yuan; CHIEF INFORMATION OFFICER (ARMY) ARLINGTON VA
|
| Net-Centric Operational Warfare (NCOW) describes how the United States Department of Defense (DoD) will conduct business operations, warfare, and enterprise management in the future. It is based on the information technology (IT) concept of an assured, dynamic, and shared information environment that provides access to trusted information for all users, based on need, independent of time and place. NCOW is an information-enabled concept of operations that generates increased combat power ... |
|
| Benchtop Insensitivity: First Steps with Shocked PETN |
JAN 2008 |
22 pages |
| Authors:
William K. Lewis; Mario E. Fajardo; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| "Insensitive Munitions (IM) are conventional weapons and ordnance that fulfill their performance objectives while minimizing collateral damage if exposed to stimuli including fires, impact and shock threats." "The statutory requirement for IM is set forth in U.S. Code, Title 10, Subtitle A, Part IV, chapter 141, Section 2389..." ... Department of Defense Acquisition Manager's Handbook for Insensitive Munitions, Jan 2004, Rev 1. |
|
| High-Order Methods For Wave Propagation |
JAN 2008 |
72 pages |
| Authors:
Miguel R. Visbal; Scott E. Sherer; Michael D. White; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
|
| In order to meet the demanding accuracy requirements in the simulation of wave propagation phenomena, a numerical approach based on high-resolution spatial schemes is presented. The time-domain AFRL code, FDL3DI, solves either the time-dependent Maxwell's equations (for CEM) or the Euler equations (for acoustics) employing 6th-order accurate compact-differences and low-pass spatial filters of up to 10th-order accuracy. The solver has been made applicable to general curvilinear grids through the incorporation ... |
|
| Thermal Simulation of Four Die-Attach Materials |
JAN 2008 |
18 pages |
| Authors:
Gregory K. Ovrebo; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| We performed a time-dependent simulation of thermal transfer in a circuit board, comparing the effects of using four different die-attach materials with high-power silicon carbide diodes. This simulation attempted to reproduce the results of a laboratory experiment in which thermal measurements were made of circuit boards under a time-varying load. |
|
| Time Dependent Behavior of Light Emitting Polymers for Potential Individual Identify Friend or Foe (IIFF) Applications |
DEC 2007 |
59 pages |
| Authors:
Johannah G. Schumacher; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Light Emitting Polymers (LEPs) are being developed for lightweight, low cost, infrared emitters for potential Individual IFF applications. The unique requirements for emitter operation (modulated, short term response) require study of time dependent optical and electrical behavior. Multiple LEP devices were evaluated to determine intensity variations and voltage response as a function of time and activations. From experimental data, it became possible to suggest approaches for creating the optimum LEP ... |
|
| Validation of Computational Fluid Dynamics Simulations for Realistic Flows (Preprint) |
DEC 2007 |
33 pages |
| Authors:
Farhad Davoudzadeh; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Strategies used to verify and validate computational fluid dynamics (CFD) calculations are described via case studies of realistic flow simulations, each representing a complex flow physics and complex geometry. Critical areas of importance to validation of a calculation are pointed out through various high fidelity physics- and engineering-based simulations. These areas include the physical model, conceptual model, boundary conditions, initial conditions, geometry, grid density and distribution, turbulence model, and numerical ... |
|
| Dueler's Dilemma: A One-Person Computer Gaming Platform for Decision Making |
NOV 2007 |
|
| Authors:
Peter Tikuisis; Allan Keefe; DEFENCE RESEARCH AND DEVELOPMENT TORONTO (CANADA)
|
 | 'Dueler's Dilemma' is one-person computer-based interactive game whereby the player, hereafter referred to as the subject, engages an unseen opponent in a non zero-sum silent shooting duel. Shots fired on a time scale from 0 to 100 by either the subject or opponent have a linearly increasing chance of hitting their target from 0 to 100%, respectively. However, the probability that either target is hit depends on the combination of ... |
|
| Tomographic Reconstruction of Atmospheric Turbulence with the Use of Time-Dependent Stochastic Inversion |
01-Sep-2007 |
11 pages |
| Authors:
Sergey N Vecherin; Vladimir E Ostashev; A Ziemann; D K Wilson; K Arnold; M Barth; NEW MEXICO STATE UNIV LAS CRUCES DEPT OF PHYSICS
|
| Acoustic travel-time tomography allows one to reconstruct temperature and wind velocity fields in the atmosphere. In a recently published paper [S. Vecherin et al., J. Acoust. Soc. Am. 119, 2579 (2006)], a time-dependent stochastic inversion TDSI was developed for the reconstruction of these fields from travel times of sound propagation between sources and receivers in a tomography array. TDSI accounts for the correlation of temperature and wind velocity fluctuations both ... |
|
| Business Process Reengineering with Information Technology at the Marine Corps Basic School |
SEP 2007 |
73 pages |
| Authors:
Brian J. Brauer; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis analyzed the principles and concepts of The Marine Corps Basic School (TBS) at the operational level and the current Information Management Systems used to track the progress of new officers. A web-enabled prototype for TBS was developed to optimize management and decision support for deliberate, time sensitive planning utilized to optimize student performance. The first iteration of the prototype was tested by the TBS Testing Officer. The results ... |
|
| Nascap-2k Self-Consistent Simulations of a VLF Plasma Antenna |
21 JUN 2007 |
17 pages |
| Authors:
M. J. Mandell; V. A. Davis; D. L. Cooke; A. T. Wheelock; C. J. Roth; AIR FORCE RESEARCH LAB HANSCOM AFB MA SPACE VEHICLES DIRECTORATE
|
| We simulate the plasma response to a high voltage square wave VLF antenna in Medium Earth Orbit plasma with Nascap-2k. The plasma is modeled with a hybrid Particle-in-cell (PlC) approach with PlC ions and fluid barometric electron densities. The plasma response, collected ion currents, and chassis floating potential are computed self-consistently with a near-square-wave bias applied to the antennas. Particle injection and splitting are used to replenish the plasma depleted ... |
|
| The Theory of Canonical Perturbations Applied to Attitude Dynamics and to the Earth Rotation. Osculating and Nonosculating Andoyer Variables |
21 JUN 2007 |
34 pages |
| Authors:
Michael Efroimsky; Alberto Escapa; NAVAL OBSERVATORY WASHINGTON DC
|
| In the method of variation of parameters we express the Cartesian coordinates or the Euler angles as functions of the time and six constants. If, under disturbance, we endow the "constants" with time dependence, the perturbed orbital angular velocity will consist of a partial time derivative and convective term that includes time derivatives of the "constants". The Lagrange constraint, often imposed for convenience, nullifies the convective term and thereby guarantees ... |
|
| 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. ... |
|
| Class Villa Materiel: What Problems Were Encountered Transiting OIF Air Transshipment Nodes |
MAR 2007 |
100 pages |
| Authors:
Jessica L. Buck; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Medical cargo (Class VIIIA) is critical to the success of the United States military stationed across the globe; therefore, the military must successfully ship its Class VIIIA materiel to the Warfighter. The shipping and handling of the time and temperature sensitive Class VIIIA materiel is a complex process. Since the initial stages of Operation IRAQI FREEDOM (OIF) the medical field has complained about Class VIIIA materiel arriving unserviceable to the ... |
|
| A Multireference Density Functional Approach to the Calculation of the Excited States of Uranium Ions |
MAR 2007 |
191 pages |
| Authors:
Eric V. Beck; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| An accurate and efficient hybrid Density Functional Theory (DFT)/Multireference Configuration Interaction (MRCI) model for computing electronic excitation energies in heavy element atoms and molecules was developed. This model incorporated relativistic effects essential for accurate qualitative and quantitative spectroscopic predictions on heavy elements, while simultaneously removing spin-multiplicity limitations inherent in the original model on which it is based. This model was used to successfully compute ground and low-lying electronic states for ... |
|
| Geospatial Informational Security Risks and Concerns of the U.S. Air Force GeoBase Program |
MAR 2007 |
166 pages |
| Authors:
Scott A. Bryant; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Technological advancements such as Geospatial Information Systems (GIS) and the Internet have made it easier and affordable to share information, which enables complex and time sensitive decisions to be made with higher confidence. Further, advancements in information technology have dramatically increased the ability to store, manage, integrate, and correlate larger amounts of data to improve operational efficiency. However, the same technologies that enable increased productivity also provide increased capabilities to ... |
|
| Naval Research Laboratory Ecological -- Photochemical -- Bio-optical--Numerical Experiment (Neptune) Version 1: A Portable, Flexible Modeling Environment Designed to Resolve Time-dependent Feedbacks Between Upper Ocean Ecology, Photochemistry, and Optics |
21 FEB 2007 |
52 pages |
| Authors:
Jason K. Jolliff; John C. Kindle; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| A modeling system has been constructed that combines ecological element cycling, photochemical processes, and bio-optical processes into a single simulation that may be coupled to hydrodynamic models that provide temperature fields as well as the advection/diffusion of state variables. The model is derived from a history of ocean biogeochemical models that describe the transformation of elemental reservoirs (carbon, nitrogen, phosphorus) based upon lower-trophic order ecosystem function. The model description of ... |
|
| Analytical Solutions for Open Channel Temperature Response to Unsteady Thermal Discharge and Boundary Heating |
Jan-2007 |
40 pages |
| Authors:
H S Tang; T R Keen; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| Analytical solutions are derived for a one-dimensional model of the bulk temperature response of open-channel flow with unsteady and nonuniform heating at an upstream boundary, the water surface, and the riverbed. The model describes the temperature variation as kinematic waves, and the solutions are explicit formulas that are comprised of transient terms, which play dominant roles at the upstream end, and equilibrium terms, which determine the temperature far downstream. It ... |
|
| 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 ... |
|
| Development of a Three Dimensional Perfectly Matched Layer for Transient Elasto-Dynamic Analyses |
DEC 2006 |
152 pages |
| Authors:
Anthony N. Johnson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A time-dependent, three-dimensional finite element approach to the development of a perfectly matched layer for numerical calculations of surface wave radiation in a half space is presented. The development of this new element required the coupling of a system of linear, second-order, partial differential equations which describe elastic wave propagation into a single weak-form (Galerkin) wave equation, from which the characteristics of a composite finite element matching layer were derived. ... |
|
| Validation for CFD Prediction of Mass Transport in an Aircraft Passenger Cabin |
NOV 2006 |
55 pages |
| Authors:
A. J. Baker; S. C. Ericson; J. A. Orzechowski; K.L. Wong; R. P. Garner; FEDERAL AVIATION ADMINISTRATION OKLAHOMA CITY OK CIVIL AEROMEDICAL INST
|
| A joint project was established to validate computational fluid dynamics (CFD) as a quantitative methodology for prediction of the distribution of pathogens released into the environmental control system (ECS)-generated ventilation flow field of an aircraft passenger cabin. Acquisition of the requisite experimental databases for three-dimensional velocity and gaseous contaminant distributions was accomplished in the FAA Civil Aerospace Medical Institute's (CAMI's) Aircraft Environmental Research Facility (AERF). The associated CFD simulations were ... |
|
| 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 ... |
|
| Castration Induced Neuroendocrine Mediated Progression of Prostate Cancer |
SEP 2006 |
8 pages |
| Authors:
Christopher P. Evans; CALIFORNIA STATE UNIV SACRAMENTO
|
| In the past twelve months we have demonstrated that bombesin stimulates the androgen receptor preferentially to a proximal androgen response element in the promoter region rather than in the enhancer region, which is primarily stimulated by androgens. We have shown that gastrin-releasing peptide prostate cancer cells have their growth in soft agar inhibited by the specific Src inhibitor AZD0530. This is a dose-dependent response. AZD0530 abolishes the nuclear translocation of ... |
|
| Low-Level Sarin (GB) Vapor Exposure in the Gottingen Minipig: Effect of Exposure Concentration and Duration on Pupil Size |
SEP 2006 |
70 pages |
| Authors:
Stanley W. Hulet; Douglas R. Sommerville; Bernard J. Benton; Jeffry S. Forster; Jacqueline A. Scotto; William T. Muse; Ronald B. Crosier; Sharon A. Reutter; Robert J. Mioduszewski; Sandra A. Thomson; EDGEWOOD CHEMICAL BIOLOGICAL CENTER ABERDEEN PROVING GROUND MD
|
| One of the goals of this study was to determine the lowest sarin (GB) vapor concentration of physiological significance. During the whole body exposure to GB vapor of a living species, the first noticeable effect is constriction of the pupil (miosis). The Gottingen minipig was chosen as a model for studying the effects of GB vapor because of the anatomical and physiological similarities between humans and minipigs. The minipigs were ... |
|
| Cost Cumulant-Based Control for a Class of Linear Quadratic Tracking Problems |
04 AUG 2006 |
10 pages |
| Authors:
Khanh D. Pham; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| The topic of cost cumulant control is currently receiving substantial research from the theoretical community oriented toward stochastic control theory. For instance, the present paper extends the application of cost cumulant controller design to control of a wide class of linear quadratic tracking systems. It is shown that the tracking problem can be solved in two parts: a feedback k-cost-cumulant (kCC) control whose optimization criterion representing a linear combination of ... |
|
| 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 ... |
|
| Time-Dependent Stochastic Inversion in Acoustic Travel-Time Tomography of the Atmosphere |
MAY 2006 |
11 pages |
| Authors:
Sergey N. Vecherin; Vladimir E. Ostashev; George H. Goedecke; D. K. Wilson; Alexander G. Voronovich; NEW MEXICO STATE UNIV LAS CRUCES DEPT OF PHYSICS
|
| Stochastic inversion is a well known technique for the solution of inverse problems in tomography. It employs the idea that the propagation medium may be represented as random with a known spatial covariance function. In this paper, a generalization of the stochastic inverse for acoustic travel-time tomography of the atmosphere is developed. The atmospheric inhomogeneities are considered to be random, not only in space but also in time. This allows ... |
|
| 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
|
| 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 ... |
|
| Modeling of Time-Dependent Thermal Effects in Cr2+-Doped Zinc Selenide Thin Disks |
FEB 2006 |
13 pages |
| Authors:
Patrick A. Berry; Kenneth L. Schepler; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SENSORS DIRECTORATE
|
| We used finite element software to model the time dependence of thermal lensing and temperature rise in a Cr2+-doped zinc selenide thin disk for pulsed pumping. Two cases, chopped cw and Q-switched pumping, were considered. The model agrees well with experimental results for the chopped pumping case but does not directly agree with Q-switched pumping because the time delay between absorption and heat transfer to the host material is not ... |
|
| Ship-Track Models Based on Poisson-Distributed Port-Departure Times |
20 JAN 2006 |
39 pages |
| Authors:
Richard Heitmeyer; NAVAL RESEARCH LAB WASHINGTON DC ACOUSTIC SIGNAL PROCESSING BRANCH
|
| This report presents two models that describe the tracks of ships during an arbitrary time interval. Both models consist of a track function that describes the tracks of the individual ships and a probability law on the total number of ships en route during the interval, the initial positions of those ships, and their nominal speeds. The probability law assumes that the ship departure times are Poisson-distributed with a time-varying ... |
|
| A Distributed Lagrange Multiplier Based Fictitious Domain Method for Maxwell's Equations |
19 JAN 2006 |
35 pages |
| Authors:
V. A. Bokil; R. Glowinski; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| We consider a time-dependent problem of scattering by an obstacle involving the solution of the two dimensional Maxwell's equations in the exterior of a domain with a perfectly conducting condition on the boundary of this domain. We propose a novel fictitious domain method based on a distributed Lagrange multiplier technique for the solution of this problem. Perfectly matched layers are constructed to model the unbounded problem. Comparisons are performed with ... |
|
| Optimization of Air Vehicle Operations Using Mixed-Integer Linear Programming |
2006 |
21 pages |
| Authors:
Corey Schumacher; Phillip R. Chandler; Meir Pachter; Lior S. Pachter; AIR FORCE RESEARCH LAB (AFRL/VACA) WRIGHT-PATTERSON AFB OH CONTROL THEORY OPTIMIZATION BRANCH
|
| A scenario where multiple air vehicles are required to prosecute geographically dispersed targets is considered. Furthermore, multiple tasks are to be successively performed on each target, i.e. the targets must be classified, attacked, and verified as destroyed. The optimal, e.g. minimum time, performance of these tasks requires cooperation amongst the vehicles such that critical timing constraints are satisfied, that is, a target must be classified before it can be attacked, ... |
|
| Effects of Conjugation in Length and Dimension on Spectroscopic Properties of Fluorene-Based Chromophores from Experiment and Theory (Postprint) |
2006 |
14 pages |
| Authors:
Loon-Seng Tan; Paul A. Fleitz; Ruth Patchter; Kiet A. Nguyen; Joy E. Rogers; Jonathan E. Slagle; Paul N. Day; Ramamurthi Kannan; UES INC DAYTON OH
|
| A series of one-photon absorption spectra for fluorene-based donor-pi;-acceptor molecules is presented and spectroscopically assigned, based upon the results obtained from time-dependent density functional theory. 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 values in some cases, ... |
|
| Predictability in Unstable, Continuous Systems/Predictability and Dynamics of Geophysical Fluid Flows |
DEC 2005 |
3 pages |
| Authors:
Roger M. Samelson; OREGON STATE UNIV CORVALLIS
|
| Research under this grant focused primarily on computations of unstable nonlinear periodic solutions, time-dependent normal modes (Floquet vectors), and singular vectors in a two-layer quasi-geostrophic channel model. The model was studied in weakly and strongly nonlinear regimes, in which small disturbances to an unstable, steady, zonal, baroclinic shear flow grow to finite amplitude and continue to vacillate irregularly for arbitrarily long times. The computation of time-dependent, normal-mode disturbances to unstable, ... |
|
| Developing a High-Resolution Tile Display Based on Commodity Components |
SEP 2005 |
36 pages |
| Authors:
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The advent of powerful, low-cost desktop computers is changing the way computational scientists visualize the results of their calculations. Traditionally, only the least complex data sets could be analyzed at the local desktop, while large, time-dependent data sets required the use of high-end graphics servers to visualize the results. Today, we can analyze the results of very large computations that were previously unimaginable on the desktop, and in some cases, ... |
|
| Simulation and Optimization Methodologies for Military Transportation Network Routing and Scheduling and for Military Medical Services |
03 AUG 2005 |
35 pages |
| Authors:
Ervin Y. Rodin; WASHINGTON UNIV ST LOUIS MO CENTER FOROPTIMIZATION AND SEMANTIC CONTROL
|
| The purpose of this present research was to develop a generic model and methodology for analyzing and optimizing large-scale air transportation networks including both their routing and their scheduling. We proposed to achieve this aim in part by studying several specific examples of current problems of this type, arising in the operations of the Air Mobility Command (AMC) at Scott AFB; and in part by developing further the various paradigms ... |
|
| Testing of Intravenous Hemostatic Agents in a Novel Swine Model of Bleeding: Preliminary Results With FXa-PCPs |
AUG 2005 |
43 pages |
| Authors:
Kathy L. Ryan; Ryan H. Dorfman; Anthony Pusateri; Richard J. Jenny; Harold G. Klemcke; ARMY INST OF SURGICAL RESEARCH FORT SAMHOUSTON TX
|
| Finding an intravenous treatment that could assist endogenous clotting mechanisms is a major mission for military researchers. Herein, we report preliminary data on the efficacy of mixtures of highly purified blood coagulation factors (FVIIa and FXa) and phospholipids vesicles (PCPS) to reduce traumatic bleeding. A novel swine model was developed in which 1) bleeding times (BT) and coagulation function could be ascertained following multiple doses of drug administration; and, 2) ... |
|
| Modeling of Beam Wave Pulse Propagation in Vegetation Using Transport Theory |
31 JUL 2005 |
92 pages |
| Authors:
Gerald M. Whitman; Felix K. Schwering; Michael Yu-Chi Wu; NEW JERSEY INST OF TECH NEWARK
|
| The scalar time-dependent equation of radiative transfer in cylindrical coordinates was used to develop several new theories- both rigorous and approximate- for propagation and scattering of beam wave pulse trains in vegetation modeled as a random medium of discrete scatterers. Plots of specific intensity and received power in the random medium (vegetation) showed distortion due to pulse broadening, angular spread, power attenuation (especially at large penetration depths), and out-of-beam scattering. ... |
|
| Simulations of Chemotaxis and Random Motility in Finite Domains |
13 JUL 2005 |
12 pages |
| Authors:
Ehsan Jabbarzadeh; Cameron F. Abrams; DREXEL UNIV PHILADELPHIA PA
|
| Rational design and selection of candidate porous biomaterials to serve as tissue engineering constructs rests on our ability to understand the influence of the porous microarchitecture on the transport of chemical species (e.g., nutrients and signaling compounds), fluid flow, and cellular locomotion and growth. We have begun to study the behavior of chemotactically mobile cells in response to unsteady signaling molecule concentration fields using a computational simulation-based model. The model ... |
|
| N-Isopropylacrylamide-Based Copolymers with Time-Dependent LCST for a Bioresorbable Carrier |
13 JUL 2005 |
|
| Authors:
Bae H. Lee; Brent Vernon; ARIZONA STATE UNIV TEMPE DEPT OF BIOENGINEERING
|
| To develop a new class of in situ-forming, injectable, and biodegradable polymeric biomaterials based on time-dependent lower critical solution temperature (LCST) properties for localized delivery, copolymers of N-isopropylacrylamide (NIPAAm), 2-hydroxyethyl methacryl lactate (HEMA-lactate) and acrylic acid (AAc) were prepared with varying mole ratios of monomers. The copolymers showed LCST and gelation properties below body temperature in 0.1 N PBS solution of pH 7.4. The LCST and gelation temperature of the ... |
|
| Applicability of the Homogeneous Nucleation Theory to the Condensation in Free Gas Expansions |
13 JUL 2005 |
9 pages |
| Authors:
M. I. Zeifman; J. Zhong; D. A. Levin; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF AERONAUTICAL ENGINEERING
|
| The traditional application of the classical homogeneous nucleation theory (CNT) to the condensation in rapidly expanding flows involves the use of the steady-state nucleation rate. Since this rate is derived under the assumption of both steady-state and isobaric/isothermal conditions, the applicability of CNT to highly nonequilibrium environments may be questionable. In addition, the usual strategy of CNT gas dynamics coupling violates the original nucleation theory even in the isothermal/isobaric environment. ... |
|
| Ultrafast Laser Studies of Molecular Rydberg Wave Packets |
07 JUL 2005 |
5 pages |
| Authors:
Stephen R. Leone; Stefan Gilb; Vilen Nestorov; Elva Torres; Alan Arrowsmith; Dalziel Wilson; CALIFORNIA UNIV BERKELEY SPONSORED PROJECTS OFFICE
|
| The goal of this work is to investigate the formation and detection of Rydberg wave packets in molecules and to explore their possible use in quantum information processing. Very few coherent superpositions of molecular Rydberg states have been experimentally realized. Therefore, this research focuses on several new ways to produce coherent superpositions of Rydberg states in molecules as well as innovative methods to detect them by kinetic-energy resolved electron detection ... |
|
Reports by Keyword(s)
TIME DEPENDENCE
