| Stress Gradient Induced Strain Localization in Metals: High Resolution Strain Cross Sectioning via Synchrotron X-Ray Diffraction (POSTPRINT) |
Apr-2008 |
12 pages |
| Authors:
M Croft; R K Sadangi; V Shukla; J Skaritka; K Sadananda; M Lakshmipathy; M Shepard; R L Holtz; K Horvath; Z Zhong; N Jisrawi; T Tsakalakos; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
 | Strain localization in the presence of a stress gradient is a phenomenon common to many systems described by continuum mechanics. Variations of this complex phenomenon lead to interesting nonlinear effects in materials/engineering science as well as in other fields. Here, the synchrotron based energy dispersive x-ray diffraction (EDXRD) technique is used for high spatial resolution profiling of both compression and tension induced strain localization in important materials/engineering problems. Specifically, compression ... |
|
| Electron Impact Excitation Cross Sections of Xenon for Optical Plasma Diagnostic |
20 NOV 2007 |
21 pages |
| Authors:
Rajesh Srivastava; INDIAN INST OF TECH ROORKEE DEPT OF PHYSICS
|
| In this project the researcher had taken up the calculation of xenon apparent emission-excitation cross sections for emission lines that have diagnostic value in the analysis of Xe-propelled electric thruster plasmas. Following conclusions were made from the study: The RDW method has been shown to be applicable to transitions between excited states. Since the excitation energy of these transitions is relatively small, first-order theories are valid at lower energies than ... |
|
| Minimizing Rail Deflections in an EM Railgun |
NOV 2006 |
7 pages |
| Authors:
J. B. Root; A. G. Littlefield; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| Electromagnetic (EM) railguns have yet to be fielded due to several technical issues that need to be worked out in the near future. One of the problems is the high electromagnetic repulsive force that pushes the rails apart and causes the armature to lose contact with them. In laboratory guns, rail deflections can be minimized by building a massive containment structure. For tactical launchers, however, there is a need to ... |
|
| Characterizing and Controlling the Effects of Differential Drag on Satellite Formations |
MAR 2006 |
127 pages |
| Authors:
James T. Wedekind; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| The ability to fly satellites in close formations represents a capability that could revolutionize the way satellite missions are designed in the future. This study examines three of the primary formation flying designs and characterizes the effects that an anomalous satellite with a slightly different cross-sectional area would have on the stability of the formation. Following the characterization of these effects, a controller is implemented to mitigate the cross-sectional area ... |
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| Stochastic Cross-Sections Based on the Small Slope Approximation: Theory |
18 JAN 2005 |
76 pages |
| Authors:
Daniel Wurmser; NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS SYSTEMS BRANCH
|
| The small slope approximation is widely used to model the incoherent scattering cross-section per unit area from stochastic rough interfaces. It consists of an integral multiplied by a prefactor. The prefactor involves a closed-form algebraic expression, but evaluation of the integral is nontrivial. This paper develops tractable methods for evaluating the integral. The rough- surface scenarios considered generally assume spectra that have tails that decrease according to a single specified ... |
|
| Arsenic Cross-Contamination in GaSb/InAs Superlattices |
AUG 2004 |
9 pages |
| Authors:
E. M. Jackson; G. I. Boishin; E. H. AIFER; B. R. Bennett; L. J. Whitman; NAVAL RESEARCH LAB WASHINGTON DC
|
| We have investigated the cross-contamination of As in GaSb/InAs superlattices. We demonstrate a method of varying the lattice constant of the superlattice. By controlling the As background pressure in the growth chamber, the strain can be controlled to about 0:01%, corresponding to As cross-incorporation variations of about +/-1%. The distribution of As is investigated by X-ray diffraction and cross-sectional scanning tunneling microscopy, and the critical thickness is obtained. |
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| An Experimental and Computational Study of the Aerodynamics of a Square Cross-Section Body at Supersonic Speeds |
MAR 2003 |
|
| Authors:
Trevor J. Birch; Simon A. Prince; Graham M. Simpson; DEFENCE EVALUATION AND RESEARCH AGENCY BEDFORD (UNITED KINGDOM)
|
 | An experimental and computational study has been carried out of investigate the aerodynamic characteristics of a square cross-section body at supersonic speeds. The results show that a square cross-section body generates higher normal force and offers improved lift-to-drag ratios when compared with conventional circular cross-section bodies for certain preferred orientations. However it was found that square cross-section bodies can also generate significant lateral forces and moments, and very complicated leeside ... |
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| A Stokes Flow Boundary Integral Measurement of Tubular Structure Cross Sections in Two Dimensions |
2003 |
5 pages |
| Authors:
Marc Niethammer; Eric Pichon; Allen Tannenbaum; Peter J. Mucha; GEORGIA INST OF TECH ATLANTA SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING
|
| In this paper we will develop a method to determine cross sections of arbitrary two-dimensional tubular structures, which are allowed to branch, by means of a Stokes flow based boundary integral formulation. The measure for the cross sections for a point on the boundary of a given structure will be the path obtained by integrating perpendicularly to the flow lines from one side of the boundary to the other. Special ... |
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| An Improved Algebraic Grid Generator for Numerical Aerodynamic Analyses of Airfoil Cross-Sections |
DEC 2002 |
157 pages |
| Authors:
Justin M. Verville; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Although computer-processing power has increased dramatically over the past few decades, minimizing computation time is still critical when conducting numerical aerodynamic analyses. One area where this is evident is the grid generation routines used in most code for this area of research. While many more sophisticated grid generation techniques are available, algebraic grid generation is still in use today due strictly to efficiency. Computational efficiency is of particularly great concern ... |
|
| DSMC Calculation of Supersonic Free Jets from an Orifice with Convex and Concave Corners |
09 JUL 2000 |
9 pages |
| Authors:
Masaru Usami; Koji Teshima; MIE UNIV TSU (JAPAN) DEPT OF MECHANICAL ENGINEERING
|
| Supersonic free jets from an orifice with convex and concave corners are investigated in three-dimensional field by the DSMC method. The plumes develop faster from the concave corners of a hexagram orifice with symmetric cross section than those from the convex corners. The mechanism of the development is revealed through the observation of velocity vectors right behind the orifice. The directions of flow are also investigated in various cross sections ... |
|
| Interpreting Interfacial Structure in Cross-Sectional STM Images of III-V Semiconductor Heterostructures |
MAY 2000 |
12 pages |
| Authors:
B. Z. Nosho; W. Barvosa-Carter; M. J. Yang; B. R. Bennett; L. J. Whitman; NAVAL RESEARCH LAB WASHINGTON DC
|
| Using model GaSb-InAs heterostructures, we have systematically examined how cross-sectional scanning tunneling microscopy (XSTM) can be used for the study of III-V heterostructure interfaces. The interpretation of interfacial structure in XSTM images is impeded by the fact that only every other III or V plane as grown on the (001) substrate is seen in each image. We show how this structural artifact affects spectral analyses of interfacial roughness, preventing an ... |
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| Nanostructural Aspects of Wear in Ion-Beam Deposited Pb-Mo-S Films |
1998 |
7 pages |
| Authors:
D. N. Dunn; K. J. Wahl; I. L. Singer; NAVAL RESEARCH LAB WASHINGTON DC
|
| Microstructural aspects of wear resistance have been investigated using cross-sectional transmission electron microscopy (TEM) to analyze both as-deposited and worn films. As deposited Pb-Mo-S films were virtually amorphous, i.e., show no long range structure. Wear tracks revealed a two-part wear process localized at the sliding surface. First, Pb-Mo-S at the sliding surface was transformed into basal-oriented, crystalline MoS2 from 1 to 4 monolayers thick. Then, as sliding continued, the MoS2 ... |
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| An Improved Semiempirical Method for Calculating Aerodynamics of Missiles with Noncircular Bodies |
SEP 97 |
139 pages |
| Authors:
Frank G. Moore; Roy M. Mcinville; Tom Hymer; NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA
|
| An improved method has been developed to compute aerodynamics of noncircular cross section shapes. The improved method is based on extending current state of the art methods for computing aerodynamics of noncircular wing- body shapes based on circular wing-body methods. Specific additions to the state of the art methods presently in use include extensions to a broader class of cross section bodies and to a higher angle of attack (AOA); ... |
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| Ultraviolet Emission Cross Sections by Electron Impact: Application to UV Dayglow and Auroral Satellite Observations |
NOV 96 |
10 pages |
| Authors:
Joseph Ajello; COLORADO UNIV AT BOULDER LAB FOR ATMOSPHERIC AND SPACE PHYSICS
|
| This program has developed for the Air Force a high resolution spectrometer, including EUV and FUV array detectors, which is the highest resolution single scattering instrument available in the US for the measurement of emission cross sections. Electron impact induced fluorescence studies have been made of emission spectra of atomic hydrogen and of molecular hydrogen, nitrogen, and oxygen. Three fully operational UV emission cross section instruments, ranging in resolving power ... |
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| Laser Probing of Cross Sections for Ionization of Excited States and Molecular Dissociation by Electron Impact |
JUL 96 |
15 pages |
| Authors:
Vincent McKoy; Santosh Srivastava; CALIFORNIA INST OF TECH PASADENA DIV OF CHEMISTRY AND CHEMICAL ENGINEERING
|
| Cross sections for electron-impact ionization of atoms and molecules and for electron-impact dissociation of molecules play an important role in determining the properties of electrical discharges, of the ionosphere and aurora, and of the plasmas that are widely used in microelectronics fabrication. The data base of these electron collision cross sections is very fragmentary or non-existent. This research has addressed these needs through the following accomplishments: Development, and application of ... |
|
| Virtual Inner Ear Endoscopyal (Videorecording). |
JUL 1996 |
|
| Authors:
BRIGHAM AND WOMEN'S HOSPITAL BOSTON MA
|
| Physical description: 1 VHS video; 1/2 in.; col.; sd.; mono; 5 mins.; standard playback sp. |
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| Virtual Inner Ear Endoscopy |
JUL 1996 |
18 pages |
| Authors:
Ferenc A. Jolesz; BRIGHAM AND WOMEN'S HOSPITAL BOSTON MA
|
| Computer Tomography (CT) and Magnetic Resonance Imaging (MRI) are non-invasive diagnostic imaging modalities that display internal anatomy of the middle and inner ear as two-dimensional cross-sectional slices. Radiologists and otolaryngologists can view these 2-D images and usually create a mental model of the 3-D structures present in the study. However, many of the tubular structures that exist in the temporal bone have complex morphology and pass back and forth through ... |
|
| Electron Interactions with Non-Linear Polyatomic Molecules and Their Radicals |
DEC 93 |
172 pages |
| Authors:
Ashok K. Jain; Charles A. Weatherford; FLORIDA AGRICULTURAL AND MECHANICAL UNIV TALLAHASSEE DEPT OF PHYSICS
|
| The work involved the computation of collision cross sections for electron collisions with non-linear polyatomic molecules and their radicals and ions. A reliable set of cross section data for elastic and inelastic processes in these systems has been produced without resorting to a fitting procedure. The computational model employed the adiabatic-nuclei-approximation for electron scattering from molecules in the gas phase. In addition, a method for calculating the required cross sections ... |
|
| Integrated Approaches to Parallelism in Optimization and Solution of Inverse Problems |
01 JAN 93 |
3 pages |
| Authors:
William Symes; RICE UNIV HOUSTON TX DEPT OF MATHEMATICAL SCIENCES
|
| Mathematical models for mechanical design problems and development of analytical and numerical tools for their solution was studied under this grant. The mathematical problems separate into ones of rods and membranes. Regarding the former, with M. Overton, the PI provided the first rigorous study of the shape of the strongest rod. In particular, within the context of the Euler- Bernoulli model, we established existence, necessary conditions, regularity, and a general, ... |
|
| Design of Round-To-Square Transition Section; Analysis and Computer Code |
JAN 93 |
19 pages |
| Authors:
Tzong H. Chen; Abdollah S. Nejad; WRIGHT LAB WRIGHT-PATTERSON AFB OH
|
| A generalized analytical form of the surface of a transition section which interfaces round and square cross sections of a wind tunnel is presented. Also included is a listing of the computer code which generates the surface coordinates in the format required by the vax computer at the Air Force Machine Shop at Wright-Patterson Air Force Base. |
|
| Electron Current Beta Limit Line Operation and Power Balance in WB Mode |
92 |
28 pages |
| Authors:
Robert W. Bussard; Katherine E. King; ENERGY/MATTER CONVERSION CORP MANASSAS VA
|
| Analyses of the systemic effects of synchrotron losses have also been made and are reported elsewhere. These show optimum operating conditions different than those for bremmstrahlung optimization. Since synchrotron radiation will be partially self-absorbed and can be partially reflected, greater flexibility in system design is allowed for its control. For this reason (i.e. it can be made 'design-specific') it has not been included here. Bremmstrahlung losses can not be mitigated ... |
|
| Burnout Thresholds and Cross Section of Power MOS Transistors with Heavy Ions |
FEB 90 |
107 pages |
| Authors:
A. E. Waskiewicz; J. W. Groninger; ROCKWELL INTERNATIONAL ANAHEIM CA
|
| Power MOSFET heavy ion-induced Single Event Burnout tests were performed jointly by representatives of the Aerospace Corporation, NASA Goddard, NWSC Crane and Rockwell International. For the most part, presented are the results of the burnout threshold and cross section characterizations performed on n-channel power MOSFETs, however a small amount of p-channel data is also included. In addition, data on the effect of temperature, gate bias, total dose and inductive loading ... |
|
| Topics in HPM (High-Power Microwave) Generation, Coupling, and Interaction |
01 JAN 90 |
184 pages |
| Authors:
Kendall F. Casey; JAYCOR FREMONT CA
|
| This document comprises a collection of technical notes on various aspects of high-power microwave (HPM) generation, coupling, and interaction. The notes were written between October 1983 and February 1986, and were originally distributed rather informally as Microwave Notes to members of the HPM community. It has since seemed worthwhile to edit and transcribe them, and to publish them as a single report. Time and resources did not permit either as ... |
|
| The Effect of Elevated Temperature on Latchup and Bit Errors in CMOS devices |
28 NOV 89 |
25 pages |
| Authors:
W. A. Kolasinski; R. Koga; E. Schnauss; J. Duffey; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| Equipment for testing microcircuits at elevated temperatures for Single Event Phenomena (SEP) such as upset (SEU) and latchup (SEL) has been developed, and measurements on several device types have been performed. Very large changes in cross section and threshold Linear Energy Transfer (LET) have been observed over the temperature range of 25 C to 120 C for SEU and SEL. |
|
| Transverse Vibrations of a Composite Cylindrical Tube of Circular Cross Section |
SEP 89 |
114 pages |
| Authors:
Raymond W. Etter; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The transverse frequencies of vibration of laminated orthotropic cylindrical shells were studied in order to compare experimental results with results predicted by p a modified Euler-Bernoulli beam theory. The structures studied had circular cross sections and were made of graphite/epoxy. Stacking sequences for the test structures were (90, + or - 603,90) and (90, + or -453, 90. The structures were tested under clamped-free boundary conditions. Testing was conducted by ... |
|
| Rectangular-to-Circular Waveguide Transitions for High-Power Circular Overmoded Waveguides |
SEP 89 |
30 pages |
| Authors:
William A. Huting; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Circular overmoded waveguide is being investigated at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) for low loss, high power microwave transmission near 3.0 GHz. Unfortunately, most microwave rather than overmoded circular waveguide. This problem is usually solved by using metallic waveguide transitions. Design objectives for such transitions include high power carrying capability, low mode conversion, low reflectivity, and low transmission loss. An overview of the theory of waveguide transition ... |
|
| Pacific Marine Radar Sea Scatter Experimental Results |
22 AUG 89 |
29 pages |
| Authors:
Dennis B. Trizna; NAVAL RESEARCH LAB WASHINGTON DC
|
| Results are presented for a low grazing angle marine radar sea scatter experiment conducted in the Pacific Ocean. A wide range of wind speeds and directions resulted in non-equilibrium sea conditions, in contrast to a previous Atlantic experiment in which ocean waves were fully developed. Statistical properties of the radar echoes are parameterized by a dual-Weibull model versus wind speed and differ from the North Atlantic data. A modified version ... |
|
| Radiation Transport Calculations of a Simple Structure Using the Vehicle Code System with 69-Group Cross Sections and the Monte-Carlo Neutron and Photon Code |
AUG 89 |
17 pages |
| Authors:
Howell Caton; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| The 58-Group Cross-Sections used in VCS calculations do not adequately described secondary gamma production in steel. In response, Oak Ridge National Laboratory (ORNL) has compiled a set of cross sections with 69 energy groups. This report documents an escalation of the 69 group cross sections on a simple steel box with various radiation liners. Also evaluated is the Monte Carlo Neutron and Photon Transport Code (MPNP). Keywords: Vehicle code system; ... |
|
| Analysis of Three- and Four-Sided Uniform Waveguides With Unusual Cross- Section/Boundary Conditions |
JAN 89 |
54 pages |
| Authors:
P. L. Overfelt; NAVAL WEAPONS CENTER CHINA LAKE CA
|
| This report gives closed-form expressions for the transverse electric and transverse magnetic modes of eight uniform waveguides with unusual cross- sectional geometry/boundary conditions. |
|
| The Electron - Water Vapor (H2O) Collision Cross Sections |
26 AUG 88 |
37 pages |
| Authors:
A. W. Ali; NAVAL RESEARCH LAB WASHINGTON DC
|
| Water vapor (H2O) is one of the minor constituents of the atmosphere and it plays an important role in the deionization processes of the partially ionized air. It controls the air conductivity, especially that of the the unheated air. Therefore, the role of H2O in modifying the electron velocity distribution in wet air is required for characterizations of partially ionized wet air. This requires the solution of a ... |
|
| Optically Controlled Attachment Studies for Diffuse Discharge Switch Applications |
JUN 88 |
146 pages |
| Authors:
P. J. Chantry; C. B. Freidhoff; C. L. Chen; D. K. Davies; L. E. Kline; WESTINGHOUSE RESEARCH AND DEVELOPMENT CENTER PITTSBURGH PA
|
| The generic properties required of the gas medium of a diffuse discharge switch are reviewed, and applied to the selection of a suitable main gas, CH4, and a number of candidate attaching gas additives for increasing the rate of recovery of the switch. The constraints placed on the latter choice include the possibility that the attachment cross section be susceptible to optical enhancement by IR irradiation using a CO2 laser. ... |
|
| Electron-Impact-Ionization and Electron-Attachment Cross Sections of Radicals Important in Transient Gaseous Discharges |
05 FEB 88 |
|
| Authors:
Long C. Lee; Dong P. Wang; Santosh K. Srivastava; SAN DIEGO STATE UNIV CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| In this research program, an apparatus using electron beam, laser beam and molecular beam has been constructed to measure the electron-impact- ionization cross sections and electron-attachment cross sections of radicals that are abundant in electrical discharge media. The electron excitation cross sections of radicals are very little known. The radical data are needed for understanding the microscopic processes of electrical discharges and for designing gaseous discharge switches. High power gaseous ... |
|
| Missile Decoy Radar Cross Section Enhancer. |
13 OCT 1987 |
|
| Authors:
John J. Harrington; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| A decoy missile having the shape of a reentry vehicle and containing a pair of conically shaped dipole jacks in tandem, the jacks are shaped and spaced to provide a desired reflective cross section at a specific frequency, the rear cover plate of the decoy is constructed of radar absorbing material to aid in the enhancement process. |
|
| Burst Generation Rates in Silicon and Gallium Arsenide from Neutron- Induced Nuclear Recoils |
15 AUG 87 |
|
| Authors:
John R. Letaw; SEVERN COMMUNICATIONS CORP SEVERNA PARK MD
|
| The HETC code (Los Alamos National Laboratory version) is used to estimate the energy spectra of residual nuclei in n-Si and n-GaAs reactions between 50 MeV and 1 GeV. A computation of the components of the burst generation rate from neutron-induced nuclear recoils between 1 MeV and 1 GeV is based on the Monte Carlo results and measured cross sections. These data may be applied to the compution of single-event ... |
|
| Neutral Beam Propagation through the Atmosphere |
15 JUN 87 |
|
| Authors:
Gabor J. Kalman; T. Li; BOSTON COLL CHESTNUT HILL MA DEPT OF PHYSICS
|
| The problem of Beam Induced Stripping (BIS) process, occuring when a neutral beam propagates through the Earth's atmosphere, has been analyzed. At high current densities the process is important and leads to a rapid disintegration of the beam. At lower current densities currently contemplated for experiments, the effect is probably not significant. Keywords: Neutral beam; Stripping; Ionization; Beam induced stripping; Polarization; Cross section. |
|
| Antiproton-Hydrogen Atom Annihilation |
MAY 86 |
|
| Authors:
David L. Morgan Jr; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| For antiproton energies of several eV or less annihilation in matter occurs through atomic rearrangement processes in which the antiproton becomes bound to a nucleus prior to annihilation. Annihilation cross sections via rearrangement at such energies are much higher than for direct antiproton nucleon annihilation and are therefore of consequence to antiproton annihilation propulsion of space craft. Existing calculations of the antiproton-hydrogen atom rearrangement cross section are semiclassical and employ ... |
|
| Best Approximation of Signal Amplitude and Delay in a Narrowband Radar |
22 JAN 86 |
|
| Authors:
Richard C. Raup; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
| The range estimation problem is generally solved by assuming a low order target mass center motion description (such as constant velocity or constant acceleration) or by postulating a well defined manuever. Assumptions are often made that require the receiver signal associated with a well tracked target to have a narrow bandwidth. These assumptions are unreasonable for certain range estimation problems. An approach general enough for use with virtually any pulsed ... |
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| The Lindhard, Nielsen and Scharff Method of Obtaining Approximate Cross Sections |
10 SEP 85 |
|
| Authors:
G. P. Mueller; NAVAL RESEARCH LAB WASHINGTON DC
|
| Scattering theory gives an exact expression for generating a differential cross section from a known inter-particle potential and, conversely, if one has a cross section, there is an exact inversion process that yields the potential that is its counterpart. Lindhard, Nielsen and Scharff (LNS) developed an approximate method to generate cross sections. Their Thomas- Fermi cross section is widely used in atomic scattering and radiation damage calculations. In this report ... |
|
| The Ballistic Research Laboratory Flash X-Ray Computed Tomography Facility for Microsecond Events |
SEP 85 |
|
| Authors:
C. K. Zoltani; K. J. White; F. A. DiBianca; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A new technique using multiple flash x-ray sources for the determination of cross-sectional density profiles of rapidly translating or dynamically deforming objects is presented. The method, and extension of the concepts of medial tomography, allows stop-action survey of events with time constants at the low end of the microsecond range, making it suitable for problems of ballistic research and materials proof testing. This report discusses the design, the components, the ... |
|
| Multiple Scatter Cross Sections for Anisotropic Kolmogoroff Turbulence |
FEB 85 |
40 pages |
| Authors:
S. P. Yukon; ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY
|
| The cross section for multiple scattering from anisotropic random media are calculated for scattering into forward and backward directions from slabs containing electron density or refractive index irregularities whose symmetry axes are aligned at an arbitrary angle to the slab face. The cross sections are calculated in the CFSB (Simulative Forward-scatter Single- backscatter) approximation using techniques used in RADC-TR-82-287 (AD-A127 873) and extended here to include arbitrary turbulence spectra and, ... |
|
| Collisional Excitation Cross Sections |
AUG 1984 |
|
| Authors:
M. J. Redmon; L. T. Redmon; B. C. Garrett; CHEMICAL DYNAMICS CORP COLUMBUS OH
|
| First principles calculations are reported of high velocity vibrational excitation and relaxation processes in several molecules of importance in plume technology. These involve collisions of atomic oxygen with HF, HC1, CO, water, and carbon dioxide. Cross sections for vibrational excitation and relaxation are reported, along with vibrational relaxation rate constants. The effect of chemical reaction channels in these systems is discussed, and is relatively unimportant except at the highest velocities ... |
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| Differential Cross Sections for Ionization of Methane, Ammonia, and Water Vapor by High Velocity Ions |
01 JUN 1984 |
|
| Authors:
W. E. Wilson; J. H. Miller; L. H. Toburen; S. T. Manson; GEORGIA STATE UNIV ATLANTA DEPT OF PHYSICS AND ASTRONOMY
|
|
| Evaluated Theoretical Cross-Section Data for Charge Exchange of Multiply Charged Ions with Atoms. III. Nonhydrogenic Target Atoms, |
1984 |
|
| Authors:
R. K. Janev; J. W. Gallagher; NATIONAL STANDARD REFERENCE DATA SYSTEM
|
| The theoretical cross-section data for single-electron capture in collisions of multiply charged ions with nonhydrogenic atoms are compiled and their accuracy is assessed. The energy per unit mass range considered is from approx. 1 dT.u to several MeV/u, u being the unified atomic mass unit. Accuracy is assessed using both pure theoretical arguments and comparison with experimental data, where available. A similar assessment is performed for the two-electron capture cross-section ... |
|
| Fluorescence and Electron Energy Loss Cross Sections in Mercuric Bromide |
22 DEC 1983 |
|
| Authors:
P. J. Chantry; C. L. Chen; WESTINGHOUSE RESEARCH AND DEVELOPMENT CENTER PITTSBURGH PA
|
| Computer modelling of HgBr discharge lasers requires as input the various cross sections for electron impact on HgBr2. This report describes measurements of the wavelength resolved emission cross section measured between 240 and 530 nm. This range encompasses three bands: The (D-X), (C-X) and B-X which have been documented and discussed previous. In addition we find a fourth band which appears on the long wavelength side of the (C-X) band, ... |
|
| Cryomicrotome Applications: Techniques for the Study of Skeletal Materials |
SEP 1983 |
|
| Authors:
K. C. Smith; C. M. Oloff; L. E. Kazarian; AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH
|
| The LKB 2250 PMV Cryomicrotome is a large sledge-type microtome designed for sectioning both undecalcified bone and specimens of large size. The maximum specimen size is 150 x 450 mm, sufficient for an entire rabbit or small monkey. |
|
| Intramultiplet Mixing in Collisions of Calcium 4s 4p 3P(0j) with Helium: Measurement of State-to-State Cross Sections |
JUL 1983 |
|
| Authors:
H.-j. Yuh; P. J. Dagdigian; JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF CHEMISTRY
|
|
| The Quantum Dynamics of Chemical Reactions |
31 MAR 1983 |
|
| Authors:
Aron Kuppermann; CALIFORNIA INST OF TECH PASADENA DIV OF CHEMISTRY AND CHEMICAL ENGINEERING
|
| In this project, we developed accurate and approximate methods for calculating cross sections of elementary reactions. These methods were applied to systems of importance for the fundamental aspects of chemical dynamics and for advanced technologies of interest to the United States Air Force. The application included calculations of three-atom exchange reactions, break-up and three-body recombination collisions and vibrational quenching by reaction. These calculations improved our understanding of such processes and ... |
|
| Absolute Collisional Excitation Cross Section Measurements Using Crossed Molecular Beams |
17 MAR 1983 |
|
| Authors:
Andrew Freedman; Alfred Rahbee; Joel A. Silver; Alan C. Stanton; AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
|
| The measurement of absolute excitation cross-sections of the asymmetric stretch mode (001) of H20 and C02 for collisions with atomic oxygen is important in understanding the signatures of high-altitude rocket plumes. Experiments are performed in a crossed molecular beam apparatus in which a CVF detector measures the collisionally-induced infrared fluorescent signal. Calibration and testing of the atomic oxygen source was completed. It was installed into the crossed beam apparatus and ... |
|
| Characteristics of a Fluted Nozzle Gas Eductor System |
MAR 1983 |
|
| Authors:
Jerry Wayne Boykin; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Cold flow tests were conducted on a four nozzle and a one nozzle gas eductor system. The nozzles employed were fluted with a constant cross sectional area. The four nozzle tests used a mixing stack length-to-diameter ratio, (L/D), of 1.5; the single nozzle tests used L/D ratios of 2.0, 1.75 and 1.5. The total cross sectional area of the four fluted nozzles to the cross sectional area of the mixing ... |
|
| A Classical Trajectory Calculation of the O + H2 Yields OH + H Cross Sections |
12 APR 1982 |
|
| Authors:
Bernard R. Johnson; AEROSPACE CORP EL SEGUNDO CA
|
| State-to-state cross sections for the reaction O+H2(v,j) yields OH(v, j) + H are calculated by classical trajectory methods. The collision velocity and the initial vibration--rotation quantum numbers are chosen to be compatible with the values these parameters would have in a high-altitude missile plume- atmosphere interaction. The computed results are least squares fit to functional forms to provide simple working formulas for the corss sections. (Author) |
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