Briefs: Electronics & Computers
Pilot Weather Advisor System Nears Realtime

The Pilot Weather Advisor (PWA) system is an automated satellite radio-broadcasting system that provides nearly realtime weather data to pilots of aircraft in flight anywhere in the continental United States. The system was designed to enhance safety in two distinct ways: First, the automated receipt...

Briefs: Electronics & Computers
T-Shaped Emitter Metal Structures for HBTs

Metal emitter structures in a class of developmental InP-based high-speed heterojunction bipolar transistors (HBTs) have been redesigned to have Tshaped cross sections. More precisely, the modified...

Briefs: Electronics & Computers
EMI Filters for Low-Temperature Applications

Filters that suppress electromagnetic interference (EMI) on signal cables connected to cryogenic electronic equipment can be made from cores consisting of high-permeability materials. The basic...

A proposed Ka-band transmitting/ receiving system would embody a unique combination of established and semi-proven design features. Although this system is intended primarily for...

Briefs: Manufacturing & Prototyping
Repairing Chipped Silicide Coatings on Refractory Metal Substrates

The space shuttle orbiter's reaction control system (RCS) is a series of small thrusters that use hypergolic fuels to orient the orbiter in space. The RCS thrusters are constructed from a special niobium-based alloy — the C-103. This alloy retains excellent mechanical...

Briefs: Manufacturing & Prototyping
Simplified Fabrication of Helical Copper Antennas

A simplified technique has been devised for fabricating helical antennas for use in experiments on radio-frequency generation and acceleration of plasmas. These antennas are typically made of copper (for electrical conductivity) and must have a specific helical shape and precise diameter.

Briefs: Semiconductors & ICs
Waveguide Power-Amplifier Module for 80 to 150 GHz

A waveguide power-amplifier module capable of operating over the frequency range from 80 to 150 GHz has been constructed. The module comprises a previously reported power amplifier packaged in a waveguide housing that is compatible with WR-8 waveguides. (WR-8 is a standard waveguide size for the...

An alternative design for dielectric optical microresonators and a relatively simple process to fabricate them have been proposed. The proposed microresonators would exploit the same...

In one of several alternative approaches to the design and fabrication of a "whispering-gallery" optical microresonator of high resonance quality (high Q), the index of...

Briefs: Physical Sciences
Graded-Index “Whispering-Gallery” Optical Microresonators

Graded-index-of- refraction dielectric optical microresonators have been proposed as a superior alternative to prior dielectric optical microresonators, which include microspheres (described in several prior NASA Tech Briefs articles) and microtori wherein electromagnetic waves...

A class of thermally stable piezoelectric and pyroelectric polymers, and an improved method of making them, have been invented. These polymers can be used as substrates for a wide...

Briefs: Materials
Combustion Synthesis of Ca₃(PO₄)₂ Net-Shape Surgical Implants

ASelf-propagating high-temperature combustion synthesis (SHS) is the basis of a method of making components of porous tricalcium phosphate [Ca3(PO4)2] and related compounds in net sizes and shapes for use as surgical implants that are compatible...

Briefs: Software
Robust Control for the Mercury Laser Altimeter

Mercury Laser Altimeter Science Algorithms is a software system for controlling the laser altimeter aboard the Messenger spacecraft, which is to enter into orbit about Mercury in 2011. The software will control the altimeter by dynamically modifying hardware inputs for gain, threshold, channel-...

Briefs: Software
DAVE-ML Utility Programs

DAVEtools is a set of Java archives (*.jar files) that embodies tools for manipulating flight-dynamics models that have been encoded in dynamic aerospace vehicle exchange markup language (DAVE-ML). [DAVE-ML is an application program, written in Extensible Markup Language (XML), for encoding complete computational models...

Briefs: Software
Software for Alignment of Segments of a Telescope Mirror

The Segment Alignment Maintenance System (SAMS) software is designed to maintain the overall focus and figure of the large segmented primary mirror of the Hobby-Eberly Telescope. This software reads measurements made by sensors attached to the segments of the primary mirror and from these...

Briefs: Software
Simulation of Dropping of Cargo With Parachutes

Decelerator System Simulation (DSS) is a computer program for predicting and analyzing the dynamics of a load of cargo dropped with parachutes from an aircraft. A DSS simulation runs from the first motion in the aircraft until the payload reaches the ground. Intended for use in support of airdrop...

Briefs: Software
Aspect-Oriented Subprogram Synthesizes UML Sequence Diagrams

The Rational Sequence computer program described in the immediately preceding article includes a subprogram that utilizes the capability for aspect-oriented programming when that capability is present. This subprogram is denoted the Rational Sequence (AspectJ) component because it uses...

Briefs: Software
Program Synthesizes UML Sequence Diagrams

A computer program called "Rational Sequence" generates Universal Modeling Language (UML) sequence diagrams of a target Java program running on a Java virtual machine (JVM). Rational Sequence thereby performs a reverse engineering function that aids in the design documentation of the target Java program....

Briefs: Software
Updated Computational Model of Cosmic Rays Near Earth

An updated computational model of the galactic-cosmic-ray (GCR) environment in the vicinity of the Earth, Earth's Moon, and Mars has been developed, and updated software has been developed to implement the updated model. The GCR model and software in their original forms, developed during the...

Briefs: Mechanical & Fluid Systems
Two High-Temperature Foil Journal Bearings

An enlarged, high-temperature -compliant foil bearing has been built and tested to demonstrate the feasibility of such bearings for use in aircraft gas turbine engines. At 150 mm in diameter, this is the largest foil bearing known to date. This bearing is a scaled-up version of a patented...

Briefs: Mechanical & Fluid Systems
Using Plates To Represent Fillets in Finite-Element Modeling

A method that involves the use of fictitious plate elements denoted bridge plates has been developed for representing the stiffnesses of fillets in finiteelement calculations of deflections, stresses, and strains in structures. In the absence of this method, it would be necessary to...

A nonlinear version of the Liouville equation based on terminal attractors is part of a mathematical formalism for describing postinstability motions of dynamical systems...

Briefs: Mechanical & Fluid Systems
Lunar Constellation of Frozen Elliptical Inclined Orbits

A document discusses the design of orbits of spacecraft for relaying communications between Earth stations and robotic and human explorers in craters in one of the polar regions on the Moon. In simplest terms, the basic problem is to design a constellation of orbits to provide continuous...

Mechanical CAD (computer-aided design) programs have become very sophisticated during the past few years. Unfortunately, there is still a portion of the engineering spectrum that cannot be...

Photonics Tech Briefs (PTB) recently presented the 2005 Readers’ Choice Products of the Year at a special awards dinner held at The Water Club in New York City. The top three...

Practical space-based coherent laser radar systems envisioned for global winds measurement must be very efficient and must contend with unique problems associated with the large platform...

The stimulation of nerve tissue is a technique that is used in both research and clinical applications. Neuroscientists use nerve stimulation to study the fundamental principles of the nervous system...

Nitrogen lasers have been used for more than 15 years in life science and forensic applications and will continue to play a role in many scientific and industrial applications. But...

A method of adaptive signal processing has been proposed as the basis of a new generation of interferometric optical profilometers for measuring surfaces. Many current optical...

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