NASA Scientific and Technical Aerospace Reports

Improvements to the AlGaN/GaN HEMT device technology was studied at the epitaxial level by MOCVD, aimed at
enhancing efficiency and linearity. A number of projects were performed under the program, including reducing the contact
resistance, introducing a type of contacts that permits very short access regions, introducing hot electron launching into the
channel, and double channel structures. Basic research in support of these projects was also performed, including studies of
non-planar selective area growth, polarization effects in AlGaN/CaN heterostructures, and doping of GaN with Fe and oxygen.
DTIC
Airborne Radar; Aluminum Nitrides; Gallium Nitrides; High Electron Mobility Transistors; Radar Equipment; Radio
Frequencies
20040074145 National Defense Univ., Washington, DC
Defense Horizons. Number 8, March 2002. Small Security: Nanotechnology and Future Defense
Petersen, John L.; Egan, Dennis M.; Mar. 2002; 7 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422476; No Copyright; Avail: CASI; A02, Hardcopy
No abstract available
Horizon; Military Technology; Nanotechnology
20040074156 National Defense Univ., Washington, DC
Defense Horizons. Number 30, July 2003. Moore’s Law: A Department of Defense Perspective
Borsuk, Gerald M.; Coffey, Timothy; Jul. 2003; 9 pp.; In English; Original contains color illustrations
Report No.(s): AD-A422393; No Copyright; Avail: CASI; A02, Hardcopy
No abstract available
Defense Program; Electronic Equipment; Horizon; Technology Assessment
34
FLUID MECHANICS AND THERMODYNAMICS
Includes fluid dynamics and kinematics and all forms of heat transfer; boundary layer flow; hydrodynamics; hydraulics; fluidics; mass
transfer and ablation cooling. For related information see also 02 Aerodynamics.
20040068125 NASA Marshall Space Flight Center, Huntsville, AL, USA
Thermostructural Analysis of Carbon Cloth Phenolics "Ply Lifting" and Correlation to LHMEL Test
Results
Clayton, Louie; 2004; 1 pp.; In English; JANNAF 14th Nondestructuve Evaluation, 30 Mar. - 1 apr. 2004, New Orleans, LA,
USA; No Copyright; Avail: Other Sources; Abstract Only
This paper provides a discussion of the history of Carbon Cloth Phenolic (CCP) ply lifting in the Redesigned Solid Rocket
Motor (RSRM) Program, a brief presentation of theoretical methods used for analytical evaluation, and results of parametric
analyses of CCP material subject to test conditions of the Laser Hardened Material Evaluation Laboratory. CCP ply lift can
occur in regions of the RSRM nozzle where ply angle to flame surface is generally less than about 20 degrees. There is a heat
rate dependence on likelihood and severity of the condition with the higher heating rates generally producing more ply lift.
The event occurs in-depth, near the heated surface, where the load necessary to mechanically separate the CCP plies is
produced by the initial stages of pyrolysis gas generation due to the thermal decomposition of the phenolic resin matrix. Due
to the shallow lay-up angle of the composite, normal components of the indepth mechanical load, due to "pore
pressure", are imparted primarily as a cross-ply tensile force on the interlaminar ply boundaries. Tensile capability in
the cross-ply (out of plane) direction is solely determined by the matrix material capability. The elevated temperature matrix
material capabilities are overcome by pressure induced mechanical normal stress and ply-lift occurs. A theoretical model used
for CCP in-depth temperature, pressure, and normal stress prediction, based on first principles, is briefly discussed followed
by a parametric evaluation of response variables subject to boundary conditions typical of on-going test programs at the
LHMEL facility. Model response demonstrates general trends observed in test and provides insight into the interactivity of
material properties and constitutive relationships.
Author
Temperature Effects; Phenolic Resins; Solid Propellant Rocket Engines; Structural Analysis; Carbon Fibers; Composite
Materials; Thermal Decomposition
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