Briefs: Mechanical & Fluid Systems

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...

Briefs: Physical Sciences

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...

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-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...

Briefs: Physical Sciences

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...

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: Photonics/Optics

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...

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

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....

Briefs: Photonics/Optics

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...

Briefs: Photonics/Optics

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...

Briefs: Photonics/Optics

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...

Briefs: Photonics/Optics

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...

Briefs: Motion Control

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...

Briefs: Electronics & Computers

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...

Briefs: Electronics & Computers

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...

Briefs: Electronics & Computers

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...

Briefs: Electronics & Computers

A number of display systems primarily used in specialized areas such as aviation, space (NASA), and military/defense employ non-standard video signal...

Briefs: Mechanical & Fluid Systems

The multidisciplinary concept of " b ioinspired e ngineering of e xploration s ystems" (BEES) is described, which is a guiding principle of the continuing effort to develop biomorphic...

Briefs: Manufacturing & Prototyping

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...

Briefs: Manufacturing & Prototyping

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...

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

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...

Briefs: Materials

Experiments have shown that superlattices that comprise alternating epitaxial layers of dissimilar paraelectric perovskites can exhibit large changes in permittivity with the application...

Briefs: Mechanical & Fluid Systems

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...

Briefs: Mechanical & Fluid Systems

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)...

Briefs: Mechanical & Fluid Systems

Curved mirrors of a proposed type would comprise lightweight sheets or films containing integral, biologically inspired actuators for controlling their surface figures. These mirrors...

Briefs: Physical Sciences
Assessment of Models of Chemically Reacting Granular Flows

A report presents an assessment of a general mathematical model of dense, chemically reacting granular flows like those in fluidized beds used to pyrolize biomass. The model incorporates submodels that have been described in several NASA Tech Briefs articles, including "Generalized...

Briefs: Physical Sciences
Numerical Study of Pyrolysis of Biomass in Fluidized Beds

A report presents a numerical-simulation study of pyrolysis of biomass in fluidized-bed reactors, performed by use of the mathematical model described in "Model of Fluidized Bed Containing Reacting Solids and Gases" (NPO-30163), which appears elsewhere in this issue of NASA Tech Briefs....

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