A report presents a theoretical and experimental study of amplification in electronic circuits that include combinations of discrete light sources (e.g., lightemitting diodes) and photodetectors (e.g., reverse-biased photodiodes), which combinations perform essentially the same functions as...

A computer program implements several aspects of the International Temperature Scale of 1990 (ITS90).

Ti3SiC2 has been proposed as a mate- rial for ohmic contacts on SiC-based electronic and microelectromechanical devices intended to operate at temperatures >600 °C and/or in corrosive environments. Although SiC is stable and devices made of SiC are capable of functioning at elevated...

A report proposes a technique for onboard updating of the orbital period of an aerobraking spacecraft in order to estimate the time of the next periapsis. The time of periapsis is nearly centered in the middle of the drag pass, and provides a convenient reference time for events in the...

A report briefly describes a user's guide for a computer program that constructs vector wind profiles on the basis of a statistical model. The monthly vector wind profiles are meant to be used (1) to estimate wind-dispersion-related dispersions of critical aerodynamic loads and...

Some experiments directed toward the development of improved hard, lubricious coating materials have involved direct fluorination of proprietary diamondlike coats on various substrates. The idea is to retain the hardness of the diamondlike material while adding surface molecular structures that impart the...

This report discusses direct numerical simulations (DNS) of a mixing layer, between a nitrogen stream and a heptane stream initially flowing at different velocities, under supercritical conditions and undergoing a transition to turbulence. Thermodynamically, supercritical conditions...

This report presents an analysis of a database from computational simulations of a droplet-laden mixing layer (i.e., evaporating droplets of a liquid fuel in air) undergoing a transition to turbulence. The basic governing equations were those of transport of discrete droplets through a...

Parameter-Variation-Principle (PVP) based Mathematical Programming (MP) is the basis of a computational method of analyzing wrinkles in membranes. Devised for original application to lightweight membrane structures in outer space, the method can also be applied on Earth to similar...

Two reports propose the development of non-ablative aeroshells for braking of spacecraft entering the atmospheres of Earth, Mars, and other planets. The primary advantages of non-ablative aeroshells, relative to ablative aeroshells, results from reduced mass and increased aerodynamic stability of the aeroshell occasioned by...

In 1987 a discovery led to the formal proof that it is possible to use chaotic functions to arrive at a nonprobabilistic and nondeterministic method normal context of the operation of this system, and by using a virtual operational environment, the investigators are manipulating data in eight dimensions, which require a...

A report describes experiments in which time-averaged and unsteady local variations in the densities of underexpanded supersonic free jets issuing from a choked circular nozzle were measured by laser-induced Rayleigh scattering. This study is part of a continuing effort to understand the...

Weighing scales (e.g., kitchen and bathroom scales) of a proposed type would incorporate sensory devices like the one described in "Low-Power, Microprocessor-Controlled Strain-Gauge Circuit" (NPO-19750), NASA Tech Briefs, Vol. 21, No. 1 (January 1997), page 45. Unlike other weighing scales...

A mathematical model has been formulated to describe the pyrolysis of biomass in a bubbling fluidized-bed reactor. The reactor is a vertical cylinder that contains a mixture of biomass particles and sand. Superheated steam enters the reactor through holes in the bottom and flows out freely at...

Epoxies and/or cyanate esters that incorporate polyhedral oligomeric silsesquioxane (POSS) compounds are undergoing development at Air Force Research Laboratory (AFRL). These formulations are expected to be useful as high-performance matrix resins for advanced, lightweight fiber/matrix composite...