April 2003

Briefs : Medical
Time-Resolved Measurements in Optoelectronic Microbioanalysis

A report presents discussion of time-resolved measurements in optoelectronic microbioanalysis. Proposed microbioanalytical "laboratory-on-a-chip" devices for detection of microbes and toxic chemicals would include optoelectronic sensors and associated electronic circuits that would...

Briefs : Electronics & Computers
Block QCA Fault-Tolerant Logic Gates

Suitably patterned arrays (blocks) of quantum-dot cellular automata (QCA) have been proposed as fault-tolerant universal logic gates. These block QCA gates could be used to realize the potential of QCA for further miniaturization, reduction of power consumption, increase in switching speed, and increased...

Briefs : Electronics & Computers
Hybrid VLSI/QCA Architecture for Computing FFTs

A data-processor architecture that would incorporate elements of both conventional very-large-scale integrated (VLSI) circuitry and quantum- dot cellular automata (QCA) has been proposed to enable the highly parallel and systolic computation of fast Fourier transforms (FFTs). The proposed circuit...

Briefs : Manufacturing & Prototyping
Block Copolymers as Templates for Arrays of Carbon Nanotubes

A method of manufacturing regular arrays of precisely sized, shaped, positioned, and oriented carbon nanotubes has been proposed. Arrays of carbon nanotubes could prove useful in such diverse applications as communications (especially for filtering of signals), biotechnology (for...

Briefs : Information Technology
Collaborative Software Development Approach Used To Deliver the New Shuttle Telemetry Ground Station

United Space Alliance (USA) developed and used a new software development method to meet technical, schedule, and budget challenges faced during the development and delivery of the new Shuttle Telemetry Ground Station at Kennedy Space Center....

Briefs : Materials
Reliability and Design Considerations for Long Life Using Mica Capacitors in High-Voltage Apps

Over the last 40 years, a series of misconceptions regarding mica capacitor applications has led novice users to consistently over- derate wound or rolled mica/ epoxy dielectric capacitors.

Mica,...

Briefs : Mechanical & Fluid Systems
Folded Resonant Horns for Power Ultrasonic Applications

Folded horns have been conceived as alternatives to straight horns used as resonators and strain amplifiers in power ultrasonic systems. Such systems are used for cleaning, welding, soldering, cutting, and drilling in a variety of industries. In addition, several previous NASA Tech Briefs...

Briefs : Mechanical & Fluid Systems
Rollable Thin Shell Composite-Material Paraboloidal Mirrors
Rollable Thin Shell Composite-Material Paraboloidal Mirrors

An experiment and calculation have demonstrated the feasibility of a technique of compact storage of paraboloidal mirrors made of thin composite-material (multiple layers of carbon...

Rollable Thin Shell Composite-Material Paraboloidal Mirrors
Briefs : Mechanical & Fluid Systems
Cellular Pressure-Actuated Joint

A modification of a pressure-actuated joint has been proposed to improve its pressure actuation in such a manner as to reduce the potential for leakage of the pressurizing fluid. The specific joint for which the modification is proposed is a field joint in a reusable solid-fuel rocket motor (RSRM), in which the...

Briefs : Mechanical & Fluid Systems
Force-Measuring Clamps

Force-measuring clamps have been invented to facilitate and simplify the task of measuring the forces or pressures applied to clamped parts. There is a critical need to measure clamping forces or pressures in some applications — for example, while bonding sensors to substrates or while clamping any sensitive or delicate...

Briefs : Mechanical & Fluid Systems
Multiple-Use Mechanisms for Attachment to Seat Tracks
Multiple-Use Mechanisms for Attachment to Seat Tracks

A Seat Track Attach Mechanism (SAM) is a multiple-use clamping device intended for use in mounting various objects on the standard seat tracks used on the International Space Station...

Multiple-Use Mechanisms for Attachment to Seat Tracks
Briefs : Mechanical & Fluid Systems
Tool for Bending a Metal Tube Precisely in a Confined Space

A relatively simple, manually operated tool enables precise bending (typically, within ±1/2° of the specified bend angle) of a metal tube located in a confined space, with a minimum of flattening of the tube and without significant gouging of the tube surface. The tool is designed for...

Briefs : Physical Sciences
Turbulence in Supercritical O₂/H₂ and C₇H₁₆/N₂ Mixing Layers

This report presents a study of numerical simulations of mixing layers developing between opposing flows of paired fluids under supercritical conditions, the purpose of the study being to elucidate chemical-species- specific aspects of turbulence. The simulations were...

Briefs : Physical Sciences
Throttling Cryogen Boiloff To Control Cryostat Temperature

An improved design has been proposed for a cryostat of a type that maintains a desired low temperature mainly through boiloff of a liquid cryogen (e.g., liquid nitrogen) at atmospheric pressure. (A cryostat that maintains a low temperature mainly through boiloff of a cryogen at...

Briefs : Software
Software for Viewing Landsat Mosaic Images

A Windows-based computer program has been written to enable novice users (especially educators and students) to view images of large areas of the Earth (e.g., the continental United States) generated from image data acquired in the Landsat observations performed circa the year 1990. The large-area...

Briefs : Software
Updated Integrated Mission Program

Integrated Mission Program (IMP) is a computer program for simulating spacecraft missions around the Earth, Moon, Mars, and/or other large bodies. IMP solves the differential equations of motion by use of a Runge-Kutta numerical-integration algorithm. Users control missions through selection from a large menu...

Briefs : Software
Software for Sharing and Management of Information

DIAMS is a set of computer programs that implements a system of collaborative agents that serve multiple, geographically distributed users communicating via the Internet. DIAMS provides a user interface as a Java applet that runs on each user’s computer and that works within the context of the...

Briefs : Software
Update on Integrated Optical Design Analyzer

Updated information on the Integrated Optical Design Analyzer (IODA) computer program has become available. IODA was described in “Software for Multidisciplinary Concurrent Optical Design” (MFS-31452), NASA Tech Briefs, Vol. 25, No. 10 (October 2001), page 8a. To recapitulate: IODA facilitates...

Briefs : Mechanical & Fluid Systems
Touchdown Ball-Bearing System for Magnetic Bearings

The torque-limited touchdown bearing system (TLTBS) is a backup mechanical- bearing system for a high-speed rotary machine in which the rotor shaft is supported by magnetic bearings in steady-state normal operation. The TLTBS provides ballbearing support to augment or supplant the magnetic...

Briefs : Mechanical & Fluid Systems
Flux-Based Deadbeat Control of Induction-Motor Torque

An improved method and prior methods of deadbeat direct torque control involve the use of pulse-width modulation (PWM) of applied voltages. The prior methods are based on the use of stator flux and stator current as state variables, leading to mathematical solutions of control equations in...

Briefs : Mechanical & Fluid Systems
Piezoelectric Positioning Enables Vibration Assisted Machining

A precision piezoelectric positioning system with high-bandwidth and high-power enables a new class of precision machining called Vibration Assisted Machining. The actuator and drive electronics optimize stroke, stiffness and dynamic response of the diamond tool.

Briefs : Photonics/Optics
Custom Software for Infrared Camera Image Acquisition and Control

Infrared cameras based on hybrid focal-plane array sensors are unlike consumer video products such as camcorders. They are complicated imaging devices that output very large amounts of digital image data at high speeds, require multiple levels of camera control, and produce...

Briefs : Photonics/Optics
Arrays of Carbon Nanotubes as RF Filters in Waveguides

Brushlike arrays of carbon nanotubes embedded in microstrip waveguides provide highly efficient (high-Q) mechanical resonators that will enable ultra-miniature radio-frequency (RF) integrated circuits. In its basic form, this invention is an RF filter based on a carbon nanotube array...

Briefs : Photonics/Optics
Optical-Quality Thin Polymer Membranes

A method of fabricating both curved and flat thin polymer membranes of optical quality has been developed. The method was originally intended to enable the fabrication of lightweight membrane imaging and interferometric optics, possibly with apertures multiple meters wide, for use in scientific instruments...

Briefs : Photonics/Optics
Carbon Nanotubes as Resonators for RF Spectrum Analyzers

Electromechanical resonators of a proposed type would comprise single carbon nanotubes suspended between electrodes (see Figure 1). Depending on the nanotube length, diameter, and tension, these devices will resonate at frequencies in a range from megahertz through gigahertz. Like the...

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