A thermosetting polyimide called "DMBZ-15" has been developed for use as a matrix material in relatively inexpensive matrix/fiber composite materials. The glass-transition temperature (T_g) of DMBZ-15 is 414°C. In contrast, the industry standard polyimide for such composites (developed in 1971 at Lewis...

We have developed an apparatus that generates a pulsed beam of fast oxygen atoms, under Small Business Innovation Research (SBIR) funding by NASA's Jet Propulsion Laboratory, to provide a ground test facility to qualify materials to be used in low Earth orbit (LEO). This development...

A process that involves reaction forming has been devised to enable the joining of high-temperature-resistant structural parts made of SiC-based materials. These materials include SiC-based ceramics and composites reinforced by fibers that are made of various component materials...

The Source Lines of Code Count (SLOCC) computer program counts the number of source lines of a computer code, as an aid in the management of software, documentation of code, estimation of cost, and satisfying miscellaneous code-metric needs. SLOCC accommodates the following programming languages: Ada, Pascal,...

Improved pressure probes have been designed to give nearly instantaneous readings of the time-varying local static pressure in flowing gases. The probes have been installed in a wind tunnel (see figure). Probes of this type could also be particularly useful as pressure-sensing instruments to help...

The aircraft-skin-rivet thermocouple is designed for measuring the temperature on the outer surface of an airplane wing under icing conditions. More specifically, its design was motivated by the need to measure the temperature near 32 °F (0 °C) on an aluminum wing skin, with an error of no more than 1 °F (0.6...

An etching and electrolyte solution called "UNIEL" has been found to be useful for electrochemical characterization as a function of depth ("electrochemical profiling" for short) of semiconductor compounds of elements from periods III and V of the periodic table; that is, InP- and...

Magnetron plasma etching has been found to be a promising technique for micromachining of single-crystal silicon carbide to fabricate microscopic structures comprising integrated mechanical, electronic, and/or optical devices. Silicon carbide offers several advantages over silicon for the...

An electromagnetic shaker based on a linear induction motor has been developed for use in flight flutter testing of aircraft. The shaker is a wing-tip-mounted unit capable of delivering root-mean-square forces as large as 140 lb (623 N) at frequencies from 10 to 60 Hz.

Some additional applications have been proposed to exploit amplification by stimulated Brillouin scattering ("Brillouin Amplification" for short), building on the concepts introduced in the preceding article. Chief among the proposed applications is conversion of a phase-modulated optical signal to an...

A hybrid-grid scheme has been developed to afford a computationally efficient means for numerically solving equations of both (1) coupled flows of heat and mass in a fluid and (2) conduction of heat in a body or bodies that bound the fluid. The scheme should prove especially beneficial...

The Paperless Procedure System (PPS) is a computer-based, semiautomated electronic system for collection and management of quality-assurance data in a large organization. The original version of PPS was designed for use by Kennedy Space Center personnel engaged in inspection tasks during...

A document presents a comprehensive overview of the technology of tapered-slot antennas and arrays of such antennas. The fundamental operation of tapered-slot antennas is not yet fully understood, and, for lack of established design rules, the designs of these antennas have been based primarily on empirical...

Improved concrete structural members such as columns, piers, and piles can be manufactured by incorporating fiber-reinforced-plastic (FRP) exterior shells and FRP interior submembers. The FRP components impart greater compressive, flexural and shear strengths and ductility to a concrete...

A low-density, creep-resistant ceramic composite material has been developed as a prototype of such materials for use at high temperatures in the next generation of aircraft engines. The material consists of Nextel (or equivalent) ceramic fibers in a matrix that is, itself, a composite...

Nearly isotropic matrix/fiber composite materials can be made quickly and at relatively low cost by resin-transfer molding. The fiber components of these materials are fine, loosely woven, three-dimensional preforms; the matrix components are epoxy or polycyanate resins. With proper tooling,...

A generic actuator has been designed to amplify the piezoelectric effect. The Bidirectional Operating Actuator (BOA) amplifies the stroke of a piezoelectric element and reorients it through a kinematic linkage.

The figure schematically illustrates an automated electronic vision system that operates in conjunction with a scanning robot to inspect a large surface for damage. In the original application for which the system was developed, the surface comprises the panels of the space shuttle thermal...

A report proposes monopropellant microthrusters for a new generation of miniature spacecraft with mission lifetimes stretching into years. These thrusters would include micromachined nozzle/chamber assemblies containing microvalves, designed according to emerging concepts of microelectromechanical systems...

An excerpt from JPL Document D-12104 presents additional information on the control system of a steerable microwave antenna that is mounted on the roof of a land vehicle and used to communicate with a geostationary satellite. The antenna and control system were described previously in...

When a silicon wafer is cut from an ingot, it is essentially impossible to align the cut perfectly with the crystal structure. Therefore the surface contour of the wafer will be a flat plane on which terraces consisting of additional atomic layers will be scattered. An atomic step will...

Experiments have shown that carbon-based materials containing pure metallic iron, alloys of iron, halides of iron, and/or oxides of iron can be synthesized from precursors of general composition CF_x, denoted loosely as graphite fluoride. Typical samples of the product...

A substrate of nickel coated with a thin layer of silver and further coated with a thin protective layer of silicon dioxide has been found to constitute an optically reflective substrate/coating system that is suitable for use at high temperature in vacuum. This system was developed...

Two closely related methods of optical inspection and computation yield data on misalignments between critical features in different layers of microfabricated devices. Examples of such devices containing features in different layers that are required to be aligned with each other...

An improved type of optoelectronic oscillator is based on Brillouin amplification. An oscillator of this type converts light energy into an electro-optical oscillation, typically at a frequency of several gigahertz. It offers several advantages over other electro-optical and over...

A report describes experiments on the wear-reducing performances of six additives to perfluoropolyether (PFPE)-based fluids in the boundary-lubrication regime. The additives were a phosphate, a thiophosphate, a β-diketone, a benzothiazole, an amide/thiol, and a sulfite. Each additive was...

Engineers have designed a new device, called the Smart Washer, that can electromagnetically detect bolthole cracks in metal structures. The device is a metal washer that contains a wire coil embedded onto the bottom surface of the washer. An alternating current drives this coil and...

Stimulated Brillouin Scattering (SBS) in optical fibers can be exploited to obtain frequency conversion with amplification and frequency-selective amplification in photonic signal-transmission and signal-processing systems. SBS has been found to be particularly useful in photonic...

Plasma windows can separate vacuum and atmosphere, or regions of high and low vacuums, in a way which facilitates transmission of various particle beams and/or radiation from low- to high-pressure regions. In a prototype device, a stabilized plasma...

A circuit has been designed to debounce a mechanical switch, which is used to activate a digital circuit. Contacts tend to make and break connections several times until the switch contacts settle out. The repetitive activity plays havoc with digital circuits because more than one state condition could...

Engineers at Rockwell International Corporation's Space System Division have developed a new method of insulating composite structural material that will stand up to the harsh environment of space. The new liquid-hydrogen cryogenic tankage...

Equations have been derived to fill a gap in previously published standard collections of stress-and-strain formulas: These are equations for deflection of a thin circular membrane that is clamped rigidly around its periphery and subjected to differential pressure. Related equations...