Briefs : Materials
Process for Smoothing an Si Substrate After Etching of SiO₂

A reactive-ion etching (RIE) process for smoothing a silicon substrate has been devised. The process is especially useful for smoothing those silicon areas that have been exposed by etching a pattern of holes in a layer of silicon dioxide that covers the substrate. Applications in...

Briefs : Materials
Flexible Composite-Material Pressure Vessel

A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure...

Briefs : Materials
Lower-Conductivity Thermal-Barrier Coatings

Thermal-barrier coatings (TBCs) that have both initial and post-exposure thermal conductivities lower than those of yttria-stabilized zirconia TBCs have been developed. TBCs are thin ceramic layers, generally applied by plasma spraying or physical vapor deposition, that are used to insulate air-cooled...

Briefs : Mechanical & Fluid Systems
Noncircular Cross Sections Could Enhance Mixing in Sprays

A computational study has shown that by injecting drops in jets of gas having square, elliptical, triangular, or other noncircular injection cross sections, it should be possible to increase (relative to comparable situations having circular cross section) the entrainment and dispersion...

Briefs : Mechanical & Fluid Systems
Probe Without Moving Parts Measures Flow Angle

The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle...

Briefs : Physical Sciences
Predicting and Preventing Incipient Flameout in Combustors

A method of predicting and preventing incipient flameout in a combustor has been proposed. The method should be applicable to a variety of liquid- and gas-fueled combustors in furnaces and turbine engines. Until now, there have been methods of detecting flameouts after they have...

Briefs : Physical Sciences
Detecting Conductive Liquid Leaking From Nonconductive Pipe

A method that can be implemented with relatively simple electronic circuitry provides a capability for detecting leakage of an electrically conductive liquid from an electrically nonconductive underground pipe. Alternatively or in addition, the method can be applied to locate the pipe,...

Briefs : Physical Sciences
Hot Films on Ceramic Substrates for Measuring Skin Friction

Hot-film sensors, consisting of a metallic film on an electrically nonconductive substrate, have been used to measure skin friction as far back as 1931. A hot film is maintained at an elevated temperature relative to the local flow by passing an electrical current through it. The power...

Briefs : Physical Sciences
Nulling Infrared Radiometer for Measuring Temperature

A nulling, self-calibrating infrared radiometer is being developed for use in noncontact measurement of temperature in any of a variety of industrial and scientific applications. This instrument is expected to be especially well-suited to measurement of ambient or near-ambient temperature...

Briefs : Manufacturing & Prototyping
Preparation of Regular Specimens for Atom Probes

A method of preparation of specimens of non-electropolishable materials for analysis by atom probes is being developed as a superior alternative to a prior method. In comparison with the prior method, the present method involves less processing time. Also, whereas the prior method yields...

Briefs : Information Technology
Combining Multiple Gyroscope Outputs for Increased Accuracy

A proposed method of processing the outputs of multiple gyroscopes to increase the accuracy of rate (that is, angular- velocity) readings has been developed theoretically and demonstrated by computer simulation. Although the method is applicable, in principle, to any gyroscopes, it is...

Briefs : Photonics/Optics
Metal Side Reflectors for Trapping Light in QWIPs

Focal-plane arrays of quantum-well infrared photodetectors (QWIPs) equipped with both light-coupling diffraction gratings and metal side reflectors have been proposed, and prototypes are expected to be fabricated soon. The purpose served by the metal side reflectors is to increase quantum...

Briefs : Photonics/Optics
Metallized Capillaries as Probes for Raman Spectroscopy

A class of miniature probes has been proposed to supplant the fiber-optic probes used heretofore in some Raman and fluorescence spectroscopic systems. A probe according to the proposal would include a capillary tube coated with metal on its inside to make it reflective. A microlens would be...

Briefs : Photonics/Optics
Thermal Load Sensors for Automotive Applications

Next-generation thermal load sensors, or combo sensors, optimize climate control and lighting in "intelligent automobiles," thereby enhancing the comfort and safety of drivers and passengers. The sensors combine performance and quality with customized design to exceed the rigorous requirements of...

Briefs : Photonics/Optics
Inverse Tomo-Lithography for Making Microscopic 3D Parts

According to a proposal, basic x-ray lithography would be extended to incorporate a technique, called "inverse tomography," that would enable the fabrication of microscopic three-dimensional (3D) objects. The proposed inverse tomo-lithographic process would make it possible to produce...

Briefs : Photonics/Optics
PC-Based Software for Pattern, Color, and Color Pattern Matching

Learning algorithms for machine vision are essential for many of the applications that require inspection and guidance. These algorithms typically require some type of learning step before the actual inspection can take place. Some of the algorithms that fall into this category...

Briefs : Photonics/Optics
Advanced Rainbow Solar Photovoltaic Arrays

Photovoltaic arrays of the rainbow type, equipped with light-concentrator and spectral-beam-splitter optics, have been investigated in a continuing effort to develop lightweight, high-efficiency solar electric power sources. This investigation has contributed to a revival of the concept of the rainbow...

Briefs : Photonics/Optics
Correcting for Beam Aberrations in a Beam-Waveguide Antenna

A method for correcting the aim of a beam-waveguide microwave antenna compensates for the beam aberration that occurs during radio tracking of a target that has a component of velocity transverse to the line of sight from the tracking station. The method was devised primarily for use in...

Briefs : Electronics & Computers
Wireless Temperature-Monitoring System

A relatively inexpensive instrumentation system that includes units that are connected to thermocouples and that are parts of a radio-communication network has been developed to enable monitoring of temperatures at multiple locations. Because there is no need to string wires or cables for communication, the...

Briefs : Electronics & Computers
Analog Binaural Circuits for Detecting and Locating Leaks

Very-large-scale integrated (VLSI) analog binaural signal-processing circuits have been proposed for use in detecting and locating leaks that emit noise in the ultrasonic frequency range. These circuits would be designed to function even in the presence of intense lower-frequency...

Briefs : Electronics & Computers
Cascade Back-Propagation Learning in Neural Networks

The cascade back-propagation (CBP) algorithm is the basis of a conceptual design for accelerating learning in artificial neural networks. The neural networks would be implemented as analog very-large-scale integrated (VLSI) circuits, and circuits to implement the CBP algorithm would be...

Briefs : Electronics & Computers
Using PXI-Based Arbitrary Waveform Generators for Non-Standard Raster/Stroke (Vector) Video

A number of display systems primarily used in specialized areas such as aviation, space (NASA), and military/defense employ non-standard video signal technologies such as raster/stroke analog video. Displays in cockpits of planes, pilot helmets, and...

Briefs : Mechanical & Fluid Systems
Bio-Inspired Engineering of Exploration Systems

The multidisciplinary concept of "bioinspired engineering of exploration systems" (BEES) is described, which is a guiding principle of the continuing effort to develop biomorphic explorers as reported in a number of articles in the...

Briefs : Manufacturing & Prototyping
Electrophoretic Deposition for Fabricating Microbatteries

An improved method of fabrication of cathodes of microbatteries is based on electrophoretic deposition. Heretofore, sputtering (for deposition) and the use of photoresist and liftoff (for patterning) have been the primary methods of fabricating components of microbatteries. The volume of...

Briefs : Manufacturing & Prototyping
Microscope Cells Containing Multiple Micromachined Wells

An improved design for multiple-well microscope cells and an associated improved method of fabricating them have been devised. [As used here, "well" denotes a cavity that has a volume of about 1 or 2 µL and that is used to hold a sample for examination under a microscope....

Briefs : Information Technology
Developing Generic Software for Spacecraft Avionics

A proposed approach to the development of software for spacecraft avionics is based partly on a concept of generic software that could be tailored to satisfy requirements for specific missions. The proposed approach would stand in contrast to the conventional approach of first defining avionics...

Briefs : Information Technology
Using Fractional Clock-Period Delays in Telemetry Arraying

A set of special digital all-pass finite- impulse- response (FIR) filters produces phase shifts equivalent to delays that equal fractions of the sampling or clock period of a telemetry- data- processing system. These filters have been used to enhance the arraying of telemetry signals...

Briefs : Materials
Perovskite Superlattices as Tunable Microwave Devices

Experiments have shown that superlattices that comprise alternating epitaxial layers of dissimilar paraelectric perovskites can exhibit large changes in permittivity with the application of electric fields. The superlattices are potentially useful as electrically tunable dielectric components...

Briefs : Mechanical & Fluid Systems
Piezoelectrically Actuated Shutter for High Vacuum

A piezoelectrically actuated shutter is undergoing development for use in experiments on laser cooling of atoms. The shutter is required to be compatible with ultrahigh vacuum [pressure of 10-9 torr (≈1.3 X 10-7 Pa) or less] and to be capable of performing reliably in the...

Briefs : Mechanical & Fluid Systems
Flight Tests of a Ministick Controller in an F/A-18 Airplane

In March of 1999, five pilots performed flight tests to evaluate the handling qualities of an F/A-18 research airplane equipped with a small-displacement center stick (ministick) controller that had been developed for the JAS 39 Gripen airplane (a fighter/attack/ reconnaissance...