Briefs: Robotics, Automation & Control

An analysis of empirical data on low-frequency oscillations in the inlet flow of a turbopump has led to the conclusion that these oscillations could be reduced or eliminated with...

Briefs: Physical Sciences

A heat exchanger made largely from pieces of single-crystal silicon has been designed for use as a recuperator in a reverse-Brayton-cycle cryocooler. Its design is optimized for transferring...

Briefs: Mechanical & Fluid Systems
Flexible Actuators for Small, Mobile, Special-Purpose Robots

A report discusses flexible microactuators for a proposed generation of small, mobile, special-purpose robots. Aspects of this topic were discussed in two previous articles in NASA Tech Briefs: "Thin-Film, Light-Energized Bimorph Micromechanical Actuators" (NPO-19607), Vol. 20, No. 8...

Briefs: Software
Software for Tooth-Contact Analysis of Spiral Bevel Gears

The SBGTAPER computer program implements a method for design and generation of spiral bevel gears that feature tapered teeth with localized bearing contact and a low level of transmission errors. The influence of misalignment on transmission errors and shift of bearing contact were...

Briefs: Mechanical & Fluid Systems

The figure presents a simplified view of a shaft seal that provides a small flow of neutral buffer gas to prevent contact between different gases contained in two adjacent regions along the shaft. In the original application,...

Briefs: Physical Sciences

A computational method for designing all-dielectric grating electromagnetic filters involves a combination of (1) numerical simulation of filter performance via integral-equation...

Briefs: Electronics & Computers

Recombination lifetime and minority-carrier lifetime are key performance parameters of semiconductor wafers used for microelectronics and solar cells. They are also...

Briefs: Electronics & Computers

A technique based on infrared-emission spectroscopy has been found to be useful for noncontact measurement of the temperature of a hot spot in the gate channel of a GaAs...

Briefs: Electronics & Computers

Rechargeable, thin-film, lithium-based microbatteries of the proposed type would be manufactured in the discharged condition, and lithium anodes would be formed in situ during...

Briefs: Information Technology

A unified theory of linear time-invariant (LTI) representations has been developed for use in the analysis and design of adaptive, narrow-band, feedforward controllers for systems...

Briefs: Robotics, Automation & Control

Adaptive performance optimization (APO) is an approach for improving aircraft performance without the need for extensive modifications of hardware. In this approach, one exploits...

Briefs: Electronics & Computers

During the development and testing of signal processing systems, it is useful to generate test signals in the laboratory in order to quantify system parameters such as dynamic range,...

Briefs: Manufacturing & Prototyping

The need for improved investment castings at Marshall Space Flight Center's Rapid Prototyping Lab has led to the development of a simple machine for centrifugal investment casting of shells....

Briefs: Information Technology

Modified Taguchi techniques of robust design optimization are used in an innovative method of training artificial neural networks — for example the network shown in the figure. As...

Briefs: Manufacturing & Prototyping

A simple change in the design of tools used in manufacturing laminated-composite-material sandwich panels reduces the floor area needed to store the tools. To give meaning to a...

Briefs: Physical Sciences

The figure shows the basic optical configuration of an improved all-reflecting imaging spectrometer. This spectrometer would differ from older spectrometers in several respects, one...

Briefs: Information Technology
Software for Assessing Effects of Designs on Operations

The Operations Impact Assessor (OIA) computer program facilitates rapid assessment of the effects of designs of spacecraft on spacecraft-processing operations at a launch site. OIA is a user-friendly, object-oriented, artificial-intelligence application program that features model-based...

Briefs: Materials

The alumina for making a suspension according to this concept must be in the form of a highly pure (preferably >99.99 percent) powder with a suitable particle-size distribution...

Briefs: Electronics & Computers

The figure illustrates a lightweight composite-material dual-beam reflector antenna for the SeaWinds spaceborne scatterometer instrument, which operates in the Ku band and is designed to...

Briefs: Manufacturing & Prototyping

Processes for fabricating thin-film type-S thermocouples on metal and silicon nitride substrates (see figure) have been developed. (A type-S thermocouple comprises one leg made of platinum and...

Briefs: Information Technology

An improved method of analysis and design offers the potential to enhance the performances of adaptive feedforward tracking systems. The method can, in principle, make it possible to...

Briefs: Electronics & Computers

The sight-to-touch translator (ST3) is a conceptual electronic apparatus that would generate a tactile representation of visible objects in its vicinity. The ST3 would be worn by a blind...

Briefs: Information Technology
Expressing Object-Oriented Concepts in Fortran 90

A methodology for object-oriented programming in Fortran 90 has been developed. The methodology provides for emulation of the most important object-oriented concepts of C++; namely, classes (including abstract data types, encapsulation, and function overloading), inheritance, and dynamic...

Briefs: Electronics & Computers

Sensors made largely of commercially available optical and electronic components are being developed for use in measuring small horizontal displacements of payloads suspended below...

Briefs: Physical Sciences

A method that includes the use of modified equations of state has been developed to enable noniterative, efficient computation of the thermodynamic behaviors of gases and liquids at...

Briefs: Materials

The figure schematically illustrates an apparatus and process in which a continuous tow of silicon carbide fibers is coated and infiltrated with a polymer/silicon slurry. A compact of such...

Briefs: Manufacturing & Prototyping

An improved process has been devised for making closed channels (e.g., coolant channels) in a heat-exchanger liner or a similar metal object. The process involves the following steps:...

Briefs: Mechanical & Fluid Systems

The figure illustrates one of several related pin-puller mechanisms that harness the recovery characteristics of a shape-memory alloy (SMA). Like some other SMA-actuated mechanisms...

Briefs: Electronics & Computers

Three coplanar-stripline circuits have been designed to perform coupling and filtering functions in microwave systems. These circuits could be incorporated into feed networks for microwave...

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