April 2002

Briefs: Information Technology
The Complexity of the Diagnosis Problem

A report presents a study of the complexity of an algorithm that performs model-based diagnosis of a complex hardware system. [In model-based diagnosis, an algorithm detects logical inconsistencies between observational data and a description (mathematical model) of the system.] In the study, the problem...

Briefs: Mechanical & Fluid Systems
Design Concepts for the ISS TransHab Module

Twelve reports present concepts for the design of structural and functional systems, subsystems, and components of the proposed TransHab module — an inflatable, lightweight habitation module that would be used by crewmembers of the International Space Station and would serve as a prototype of...

Briefs: Physical Sciences
Characteristics of Supercritical Transitional Mixing Layers

This report describes a study of threedimensional, temporal mixing layers between different fluids initially flowing at different velocities under supercritical conditions. The study involved direct numerical simulations by use of a validated mathematical model of high-pressurefluid...

Briefs: Physical Sciences
Infrared CO2 Sensor With Built-In Calibration Chambers

A proposed infrared CO2 sensor, operated in conjunction with suitable readout, data-processing, and control circuitry, could be calibrated repeatedly during operation to compensate for changes in sensor response induced by such phenomena as aging and changes in temperature. The...

Briefs: Physical Sciences
Solid-State Potentiometric CO Sensor

A solid-state sensor was developed that measures the concentrations of one or more gases of interest in a mixture of gases. This simple solid-state sensor produces a voltage signal that is sensitive to CO concentration from percent to ppm (parts per million) levels. It was intended originally for use in...

A relatively inexpensive Sun sensor for determining the absolute heading of planetary rovers to within ± 3° using a monochrome charge-coupled device (CCD) camera is presented....

A method of designing improved monolithic planar arrays of superconducting tunnel junctions (STJs) for use as photodetectors has been conceived. These arrays would be suitable for...

Briefs: Electronics & Computers
Development of Cognitive Sensors

A technical report enunciates the concept of a hierarchy of sensor classes (meaning transducers, associated circuitry, and embedded software) that have different levels of intelligence, and discusses issues pertaining to the development of sensors of the highest level of intelligence, called cognitive. The other...

A “smart” back-gate driver circuit has been proposed to enable the operation, at voltages higher than were previously possible, of a silicon-on-insulator (SOI) complementary metal...

A method of estimating the pointing error of an offset-conic-section reflector antenna equipped to receive in both right circular polarization (RCP) and left circular polarization (LCP)...

Briefs: Software
Advanced Fatigue-Crack-Growth and Fracture-Mechanics Program

The NASGRO 3.0 computer program is an advanced version of a program used by NASA and the European Space Agency for fracture-control analysis of space-system structures and other hardware. The prior version, NASA/FLAGRO 2.0, was described in “Updated Fatigue-Crack-Growth and...

Briefs: Software
Software for Sequencing Spacecraft Actions

SEQ_GEN is a component of the Sequence Subsystem computer program, which assists in generating a sequence of commands to be executed by a control computer aboard a spacecraft to perform scientific observations and supporting engineering actions in response to requests by numerous users. SEQ_GEN assists...

Briefs: Software
Program Distributes and Tracks Organizational Memoranda

Closed Loop Accounting Management System (CLAMS) is a computer program for Web-based distribution and tracking of memoranda within an organization. An item for distribution is entered by a user who has administrative access. The item is assigned to affected users, to whom e-mail messages...

A device based on the transport of water through a membrane to a vacuum has been developed for dehumidifying a stream of air in the life-support system of a spacecraft or space suit. The...

A mount has been devised to satisfy a requirement to suspend a highly precise, flat, circular, low-thermal-expansion glass mirror in a horizontal plane with its reflective side...

In an advanced method of administering drugs to target sites in human bodies, the drugs in liquid form are contained in microcapsules that are injected, and then, by exposing the...

Briefs: Medical
Combinatorial Drug Design Augmented by Information Theory

A proposed method of designing antiviral drugs provides for the utilization of combinatorial-chemistry techniques that have been used previously for this purpose, in conjunction with applicable principles of information theory. In its information-theoretic aspect, the method can be...

An optical absorbance cell that offers a selection of multiple optical path lengths has been developed as part of a portable spectrometric instrument that measures absorption spectra of small...

A mathematical model has been developed for use in analyzing the dynamics of an isothermal, non-chemically-reacting mixture of particles in a bubbling fluidized bed. Although the...

High-throughput, non-imaging, secondary concentrating optics that utilize refraction and total internal reflection are undergoing development for use in conjunction with advanced...

Briefs: Physical Sciences
Cold Flow Calorimeter

The cold flow calorimeter is an apparatus for measuring a possibly rapidly varying heat-transfer coefficient on a surface. The cold flow calorimeter includes (1) a small strain gauge bonded to a small, thin steel shim that is placed on the surface of interest and (2) a circuit that controls the electric power supplied to...

The Continuous Hazard Tracking and Failure Prediction Methodology (CHTFPM) is a proactive methodology for gathering and analyzing information about a system in order to prevent...

A method of estimating and correcting for the effect of polarization leakage on the response of a heterodyne optical interferometer has been devised. In a typical application in which...

An efficient artificial-intelligence-type algorithm for the propagation of temporal constraints has been devised for incorporation into software that performs scheduling...

Continuous Activity Scheduling Planning Execution and Replanning (CASPER) is a computer program for automated planning of interdependent activities within a system subject to requirements,...

A technique for projecting holographic images to make both still and moving three-dimensional displays is undergoing development. Unlike older techniques based on stereoscopy to give...

An electrometer developed for measuring the triboelectric responses of soils on Mars is also potentially useful on Earth for identifying some materials via their triboelectric responses....

"Laser-based adaptive wavelength division multiplexing and code division multiplexing" (LAWDM-CDM) is the name of a method that has been proposed to increase security,...

A magnetically suspended, motor-driven light-chopping wheel has been developed as an alternative to a traditional light-chopping wheel suspended on ball bearings. This chopper (see figure) is...

A video camera has been integrated with a tracking pedestal (see figure) for tracking of aircraft and spacecraft. The camera is of a high-definition (1,280 × 720 pixels),...

Briefs: Photonics/Optics
Mesoscopic Steerable Mirror

A proposed lightweight, micromachined, multiaxis-steerable mirror would have mesoscopic dimensions. Its steering function would involve mesoscopic positional excursions of its support points and would be...

Briefs: Mechanical & Fluid Systems
Heart-Pump-Outlet/Cannula Coupling

A fluid coupling has been developed for use in securing a vascular outflow graft (cannula) to the outlet of a surgically implanted NASA/DeBakey heart assist pump. The design of the coupling can also be...

Small, instrumented, expendable robotic aircraft and projectiles have been proposed for use in scouting for targeted new sites by providing closeup images with ~10-cm resolution,...

Briefs: Motion Control
Firmware for a Small Motion- Control Processor

A C-language computer program implemented as firmware controls the operations of a microprocessor on a 3-by- 1-inch (approximately 76-by-25-mm) motion-control circuit board denoted a widget board. The firmware implements a serial communication interface according to the inter integrated circuit bus...

Briefs: Mechanical & Fluid Systems
Gear Bearings and Gear-Bearing Transmissions

Gear bearings are conceptual mechanical components so named because they function as gears and as roller and/or thrust bearings. Gear bearings will be essential components of the next generation...

Briefs: Mechanical & Fluid Systems
Linear Dynamometer With Variable Stroke and Frequency

An improved linear dynamometer has been developed for testing linear alternators that are to be used to convert mechanical power to electrical power in free-piston Stirlingcycle engines....

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