Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Air Force Institute of Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 3031 - 3047 of 3047

Full-Text Articles in Physical Sciences and Mathematics

Operating Characteristics Of Xenon Gas Discharges, Michael E. Ruark Dec 1990

Operating Characteristics Of Xenon Gas Discharges, Michael E. Ruark

Theses and Dissertations

The voltage-current and spectral line intensity-current characteristics were measured for four Xenon gas discharges. The four discharge configurations were made up of two tubes, each examined at pressures of 1 and 10 Torr. The first tube was a hot filament tube with a 1 cm radius, and the second a cold cathode type tube of radius .3 cm. Intensity dependence upon current was primarily linear in all cases with some important deviations. The hot filament tube at 10 Torr showed a large decrease in intensity between 4 and 6 mA in the 8409 angstrom line. This is thought to be …

Go to article

Energy Transfer In Singlet Oxygen And Bromine Monofluoride, Barrett F. Lowe Dec 1990

Energy Transfer In Singlet Oxygen And Bromine Monofluoride, Barrett F. Lowe

Theses and Dissertations

The interhalogen molecule, bromine monofluoride (BrF), is currently under study as a potential candidate for a visible chemical laser medium. Previous studies have shown a strong emission from BrF(B3π(O+)) in the presence of singlet oxygen. While singlet oxygen will pump BrF(X) to BrF(B), the exact mechanism is not known. Chemiluminescence observed from BrF(B) excited by oxygen in a gas flowtube was used to study the energy transfer mechanism. The objective of this research was fourfold. First, the pumping process was identified as a 3- Body Mechanism. Second, the observed vibrational distribution clearly showed the population of …

Go to article

Fluorescent Lifetime Measurements Of Rare Earth Elements In Gallium Arsenide, Danny J. Topp Dec 1990

Fluorescent Lifetime Measurements Of Rare Earth Elements In Gallium Arsenide, Danny J. Topp

Theses and Dissertations

Lifetime measurements of the excited states of three GaAs semiconductors doped with the rare earth elements Erbium (ER), Praseodymium (Pr) , and Thulium (Tm) has been studied using a pulsed nitrogen laser and germanium detector. The measurements were made with an experimental set up with a system response time of 0.34 micro seconds. A 330 milliwatt nitrogen laser with a wavelength of 3370 angstrums was used to excite transitions of the rare earth elements.

Go to article

Mapping An Object-Oriented Requirements Analysis To A Design Architecture That Supports Design And Component Reuse, Kelly L. Spicer Dec 1990

Mapping An Object-Oriented Requirements Analysis To A Design Architecture That Supports Design And Component Reuse, Kelly L. Spicer

Theses and Dissertations

Design reuse has more potential for increasing the productivity of software development and maintenance than do traditional approaches to software reuse that emphasize reuse of smaller components. Current software development methods do not promote design reuse. The literature contains limited documented research on the subject, but enough that some design reuse principles can be gleaned. Among these principles are that reusable designs should be applicable within some domain of application, have a consistent structure, provide a method for instantiating the design, avoid object nesting, and promote reuse of smaller components as well. A design mapping method from an object-oriented requirements …

Go to article

A Remote Visual Interface Tool For Simulation Control And Display, William J. Derouchey Dec 1990

A Remote Visual Interface Tool For Simulation Control And Display, William J. Derouchey

Theses and Dissertations

This thesis discusses the design and development of the Visual Interactive Simulation Interface Tool (VISIT). VISIT was designed to provide the graphical representation and user interface for a simulation that is running on another processor utilizing internet communications. The system provides support for various input devices to control the simulation display and environment. Simulation objects are displayed using either a three-dimensional wireframe representation or a Gouraud shaded representation. Viewer interaction to the simulation is provided by a collection of commands that allow the viewer to initialize, start, stop, abort, and restart the simulations. The viewer also has the ability to …

Go to article

Analysis Of Space Radiation Effects In Gallium Arsenide And Cadmium Selenide Semiconductor Samples Using Luminescence Spectroscopic Techniques, Brad Lee Shaffer Dec 1990

Analysis Of Space Radiation Effects In Gallium Arsenide And Cadmium Selenide Semiconductor Samples Using Luminescence Spectroscopic Techniques, Brad Lee Shaffer

Theses and Dissertations

Analysis of space radiation effects in gallium arsenide and cadmium selenide semiconductor samples using luminescence spectroscopic techniques. The M0006 semiconductor samples were placed into a 28.5 degree inclination, 480 km altitude, near-circular orbit aboard the Long Duration Exposure Facility satellite and exposed to direct space environment for a period of 11 months, and were shielded by 0.313 inches of aluminum for another 58 months. The samples were examined for changes using cathodoluminescence and photoluminescence in various wavelength regions from 0.5 to 1.8 microns. Samples were cooled to approximately 10 degrees Kelvin in a vacuum of 10-8.

Go to article

A Comparison Of Human-Computer Interfaces In Air Force Organizations, Michael G. Morris Dec 1990

A Comparison Of Human-Computer Interfaces In Air Force Organizations, Michael G. Morris

Theses and Dissertations

This thesis investigated differences in organizational efficiency and effectiveness for users of graphical user interfaces and text-based interfaces on personal computers in Air Forces offices. Areas of interest included amount of time required to learn the basic system, amount of time required to learn new application, users' ratings of user-friendliness, users' perceptions of the extent that their system help them perform in their job, the number of software packages used on the job by users of each system, user satisfaction, responsible authorities' ratings of quality of output, and the relationship between user job experience level and interface used on the …

Go to article

Continuous Wave And Pulsed Solid State Laser Model, Matthew D. Rotondaro Nov 1990

Continuous Wave And Pulsed Solid State Laser Model, Matthew D. Rotondaro

Theses and Dissertations

A solid state laser is modeled for use on a personal computer. The model can accurately represent Nd:YAG and Nd:Glass lasers during both continuous wave and repetitively pulsed operation. The large number of input variables allow the user to make changes to the cavity, optical pump source, and the cooling system. The model calculates the energy, power, and divergence angle of the beam along with other variables. Because of its user-friendly interface, it is possible for someone with limited laser experience to obtain useful information.

Go to article

Monte Carlo Simulation Of Atmospheric Neutron Transport At High Altitudes Using Mcnp, Donald R. Culp, David L. Monti, James R. Shoemaker, David Wesley, Kirk A. Mathews Aug 1990

Monte Carlo Simulation Of Atmospheric Neutron Transport At High Altitudes Using Mcnp, Donald R. Culp, David L. Monti, James R. Shoemaker, David Wesley, Kirk A. Mathews

AFIT Documents

Neutron transport calculations were performed using the Monte Carol code, MCNP. The transport problem considered has a point source at high altitude (40 km). Since atmospheric density decreases with altitude, two-dimensional effects (cylindrical coordinates) can be important. Results were compared to those obtained with the SMAUG-II computer code, which performs mass-integral scaling of approximate fits to one-dimensional spherical discrete ordinates solutions. These comparisons show the importance of two-dimensional computations. The report discusses practical issues of applying MCNP to this problem, without code modifications and includes example input files for MCNP and for SMAUG-II. Computational modelling of neutron transport in the …

Go to article

An Abstract Data Model For The Idef0 Graphical Analysis Language, Gerald R. Morris, Thomas C. Hartrum, Mark A. Roth Jan 1990

An Abstract Data Model For The Idef0 Graphical Analysis Language, Gerald R. Morris, Thomas C. Hartrum, Mark A. Roth

AFIT Documents

IDEF0 is the United States Air Force's ICAM (Integrated Computer Aided Manufacturing) Definition Method Zero graphical analysis language, a subset of Ross' Structured Analysis (SA) language. The language is also an excellent methodology for performing a requirements-phase analysis for any software development project. We present an abstract data model for IDEF0 using entity-relationship diagrams. This model helps to mitigate some of the ambiguities inherent in IDEF0. The model is divided into two parts representing the analysis data (the essential data model) and the graphical data (the drawing data model). This dual modeling approach allows for the …

Go to article

Synthetic Aperture Multi-Telescope Tracker Apparatus, Richard A. Carreras, Salvatore J. Cusumano, Morton B. Jenks, Robert I. Suizu May 1987

Synthetic Aperture Multi-Telescope Tracker Apparatus, Richard A. Carreras, Salvatore J. Cusumano, Morton B. Jenks, Robert I. Suizu

AFIT Patents

A plurality of telescopes provide output return signals which are applied both directly and in sampled form to a photo-detector cell. The detected signals from the photo-detector will represent the constant and transient errors of the telescope system. A low pass filter insures that the tracker provides only the constant or D.C. component of the error, while a high pass filter insures that the existing measuring devices for each telescope beam provide only the transient or A.C. component of the error. The A.C. and D.C. error signals are summed together with the appropriate applied gains on each channel such that …

Go to article

Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut Jan 1987

Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut

AFIT Patents

An apparatus and technique are described for phasing the outputs of a multiplier telescope array used as a laser transmitter. The technique uses samples of the transmitted beams to control optical path lengths through the separate telescopes so that the beams add coherently at the receiver. The phasing concept is applicable both to systems which provide inputs to the multiple telescopes by dividing a single laser beam and to systems in which the inputs to the telescopes and multiple, phase-locked laser beams. The approach is also compatible with single line and multi-line lasers, and it does not entail stringent alignment …

Go to article

Stochastic Estimation Applied To The Land Speed Of Sound Record Attempt By A Rocket Car, David A. Reinholz Dec 1983

Stochastic Estimation Applied To The Land Speed Of Sound Record Attempt By A Rocket Car, David A. Reinholz

Theses and Dissertations

Optimal linear smoothing theory is applied to the data from the Speed of Sound record attempt of a three-wheeled rocket car on 17 December 1979. A forward-backward estimation method is used which employs a seven state forward-running extended Kalman filter and a Meditch-form backward recursive 'fixed-interval' smoothing algorithm. Data for this analysis is supplied by a longitudinal accelerometer mounted on the vehicle and tracking radar measurements of range, azimuth, and elevation. States of interest include two components of vehicle position and velocity, accelerometer time-correlated error, and radar range and azimuth bias errors. Two iterations of the forward-backward smoothing algorithm provide …

Go to article

Global Bifurcation Theorems For Nonlinearly Perturbed Operator Equations, John Macbain Jan 1976

Global Bifurcation Theorems For Nonlinearly Perturbed Operator Equations, John Macbain

Faculty Publications

No abstract provided.

Go to article

Lasing Conditions Of Elemental Sulfur In A Gas Discharge, David E. Egbert Sep 1972

Lasing Conditions Of Elemental Sulfur In A Gas Discharge, David E. Egbert

Theses and Dissertations

The partial pressures from heated sulfur crystals and helium, and sulfur and nitrogen required for ionic sulfur laser action in a gas discharge were determined. Previous work with sulfur lasers is reviewed and population inversion mechanisms are presented for the ionic sulfur laser lines. Possible excitation mechanisms are presented for both electron and ion or atomic collision excitation. Transition diagrams for all the known ionic sulfur laser transitions and an approximate potential energy curve for the diatomic sulfur molecule are presented. Laser action was achieved only when a spark gap pulser was used with a laser tube especially designed to …

Go to article

Software Simulation Of The D17b Computer, Bruce Chatterton Mar 1972

Software Simulation Of The D17b Computer, Bruce Chatterton

Theses and Dissertations

A software program has been written which simulates the functions of the Minuteman D17B computer at the register transfer level. The simulation program is written in the FORTRAN Extended language to be used on the Intercom System (teletype) of a CDC 6600 computer system. The simulation program consists of a main program and eight subroutines. A programming language for the D17B simulation was formed which contains numbers and load codes, switches, and miscellaneous commands. Example programs run on the simulated computer have been included to show the types of output available.

Go to article

Investigation Of The Platinum-Rich Portion Of The Platinum-Tantalum Phase Diagram, Bob Dean Browning Aug 1961

Investigation Of The Platinum-Rich Portion Of The Platinum-Tantalum Phase Diagram, Bob Dean Browning

Theses and Dissertations

The Pt-Ta binary system was investigated at two isotherms;1000°C and 1500°C, and at eleven alloy compositions in the range of 50 to 100 atomic percent platinum. The alloys were examined by x-ray diffraction and metallography. Three intermetallic compounds, Pt2Ta, Pt3Ta, and Pt4Ta were found to exist in this composition range. The Pt4Ta intermetallic appeared only at the 1500°C isotherm. Platinum dissolved tantalum substitutionally to 90 atomic percent at 1500 °C and to approximately 80 atomic percent at 1000 °C.

Go to article

First Prev