A feedback position-control system has been developed for maintaining the concentricity of a turbofan with respect to a nacelle during acoustic and flow tests in a wind tunnel. The system is needed for the following reasons:

Ultra-lightweight, self-deployable wheels made of polymer foams have been demonstrated. These wheels are an addition to the roster of cold hibernated elastic memory (CHEM) structural applications. Intended originally for use on nanorovers (very small planetary-exploration robotic vehicles), CHEM wheels could...

A small prototype mobile robot is capable of (1) hopping to move rapidly or avoid obstacles and then (2) moving relatively slowly and precisely on the ground by use of wheels in the manner of previously reported exploratory robots of the "rover" type. This robot is a descendant of a more primitive hopping robot...

There is a continuing effort to develop improved O rings for sealing joints in solid-fuel rocket motors. Following an approach based on the lessons learned in the explosion of the space shuttle Challenger, investigators have been seeking O-ring materials that exhibit adequate resilience...

Two techniques have been proposed to increase the efficiency of coupling of light from lasers to Cassegrain telescopes and, in general, telescopes with secondary or tertiary mirror obscuration. The need to increase the efficiency of coupling arises in laser transmitters of lidar and...

InAs quantum-dot lasers that feature distributed feedback and lateral evanescent-wave coupling have been demonstrated in operation at a wavelength of 1.3 µm. These lasers are prototypes of optical-communication oscillators that are required to be capable of stable single-frequency,...

Sensor systems are under development for use in real-time detection and quantitation of microbes in water without need for sampling. These systems include arrays of optical sensors; miniature, portable electronic data-acquisition circuits; and optoelectronic interfaces between the...

A spacecraft may be unable to communicate critical data associated with a serious or catastrophic failure. A brief report proposes a system, somewhat like a commercial aircraft "black box," for retrieving these data. A microspacecraft attached to the prime spacecraft would continually store recent...

A proposed integrated circuit based on quantum-dot cellular automata (QCA) would function as a bit-serial adder. This circuit would serve as a prototype building block for demonstrating the feasibility of quantum-dots computing and for the further development of increasingly complex and increasingly capable...

Architectures that would exploit the distinct characteristics of quantum-dot cellular automata (QCA) have been proposed for digital communication networks that connect advanced digital computing circuits. In comparison with networks of wires in conventional very-large-scale integrated (VLSI)...

A radio receiver system that features enhanced capabilities for remote sensing by use of reflected Global Positioning System (GPS) signals has been developed. This system was designed primarily for ocean altimetry, but can also be used for scatterometry and bistatic synthetic aperture...

A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric- power generators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about...

Pneumatically actuated miniature peristaltic vacuum pumps have been proposed for incorporation into advanced miniature versions of scientific instruments that depend on vacuum for proper operation. These pumps are expected to be capable of reaching vacuum-side pressures in the torr to...

Reactive-ion etching (RIE) under conditions described below has been found to be a suitable means for patterning piezoelectric thin films made from such materials as PbZr_1-xTi_xO₃ or Ba_xSr_1-xTiO₃. In the original...

A process for transferring an entire wafer-level micromachined silicon structure for mating with and bonding to another such structure has been devised. This process is intended especially for use in wafer-level integration of microelectro- mechanical systems (MEMS) that have been...

Nielsen Engineering & Research (NEAR) recently developed an ultrathin data acquisition system for use in turbomachinery testing at NASA Glenn Research Center. This system integrates a microelectro- mechanical-systems- (MEMS-) based absolute pressure sensor [0 to 50 psia (0 to 345 kPa)], temperature sensor,...

A proposed quantum-computing algorithm would perform a search for an item of information in a database stored in a Hilbert-space memory structure. The algorithm is intended to make it possible to search relatively quickly through a large database under conditions in which available computing resources would...

A new method of robust, autonomous real-time diagnosis of a time-varying complex system (e.g., a spacecraft, an advanced aircraft, or a process-control system) is presented here. It is based upon the characterization and comparison of (1) the execution of software, as reported by discrete...

A new method of calculating the root-mean-square (rms) pointing jitter of a scientific instrument (e.g., a camera, radar antenna, or telescope) is introduced based on a state-space concept. In comparison with the prior method of calculating the rms pointing jitter, the present method...

A high-level parametric mathematical model for estimating the costs of testing rocket engines and components at Stennis Space Center has been implemented as a Microsoft Excel program that generates multiple spreadsheets. The model and the program are both denoted, simply, the Cost...

The Virtual EDF Builder (where "EDF" signifies Electronic Development Fixture) is a computer program that facilitates the use of the Internet for building and displaying digital models of three- dimensional (3D) objects that ordinarily comprise assemblies of solid models created...

Functional-layer software for the Coupled Layer Architecture for Robotics Autonomy (CLARAty) is being developed. [CLARAty was described in "Coupled-Layer Architecture for Advanced Software for Robots" (NPO-21218), NASA Tech Briefs, Vol. 26, No. 12 (December 2002), page 48. To recapitulate: CLARAty was proposed...

A Java-language library supports input and output (I/O) of image data and metadata (label data) in the format of the Video Image Communication and Retrieval (VICAR) image-processing software and in several similar formats, including a subset of the Planetary Data System (PDS) image...

A software system processes navigational and sensory information in real time to generate a three- dimensional- appearing image of the external environment for viewing by crewmembers of a windowless aerospacecraft. The design of the particular aerospacecraft (the X-38) is such that the...

The performance of a composite part is primarily determined by the orientation of fibers in the plies. Designers wishing to exploit the full potential of composite materials, while avoiding manufacturing problems and part failures, must define and control fiber...

Electrolytes comprising LiPF₆ dissolved at a concentration of 1.0 M in three different mixtures of alkyl carbonates have been found well suited for use in rechargeable lithium-ion electrochemical cells at low temperatures. These and other electrolytes have been investigated...

High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition-metal nitrides (in particular, Fe₃N and TiN) offer a desirable combination of high electrical conductivity and...

A report proposes the use of cold hibernated elastic memory (CHEM) foam structures to cushion impacts of small (1 to 50 kg) exploratory spacecraft on remote planets. Airbags, which are used on larger (800 to 1,000 kg) spacecraft have been found to (1) be too complex for...

Improved energy- absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways...

Simple viscoelastic dampers have been invented for use on the root attachments of turbomachine blades. These dampers suppress bending- and torsion-mode blade vibrations, which are excited by unsteady aerodynamic forces during operation. In suppressing vibrations, these dampers reduce fatigue...