July 2003

Briefs : Medical
Real-Time, High-Frequency QRS Electrocardiograph

An electronic system that performs real-time analysis of the low-amplitude, high-frequency, ordinarily invisible components of the QRS portion of an electrocardiographic signal in real time has been developed. Whereas the signals readily visible on a conventional electrocardiogram (ECG) have...

Briefs : Electronics & Computers
Radio System for Locating Emergency Workers

A system based on low-power radio transponders and associated analog and digital electronic circuitry has been developed for locating firefighters and other emergency workers deployed in a building or other structure. The system has obvious potential for saving lives and reducing the risk of...

Briefs : Electronics & Computers
Capacitor-Chain Successive-Approximation ADC

A proposed successive approximation analog-to-digital converter (ADC) would contain a capacitively terminated chain of identical capacitor cells (see figure). Like a conventional successive approximation ADC containing a bank of binary scaled capacitors, the proposed ADC would store an input voltage...

Briefs : Electronics & Computers
Simpler Alternative to an Optimum FQPSK-B Viterbi Receiver

A reduced-complexity alternative to an optimum FQPSK-B Viterbi receiver has been invented. As described below, the reduction in complexity is achieved at the cost of only a small reduction in power performance [performance expressed in terms of a bit-energy-to-noise-energy ratio (Eb/N0)...

Briefs : Electronics & Computers
Multilayer Patch Antenna Surrounded by a Metallic Wall

A multilayer patch antenna, similar to a Yagi antenna, surrounded by a metallic wall has been devised to satisfy requirements to fit within a specified size and shape and to generate a beam with a half-power angular width of ≤40°. This antenna provides a gain of about 14 dB; in contrast,...

Briefs : Mechanical & Fluid Systems
Analysis of Designs of Space Laboratories

A report presents a review of the development of laboratories in outer space, starting from the pioneering Skylab and Salyut stations of the United States and the former Soviet Union and progressing through current and anticipated future developments. The report includes textual discussions of...

Briefs : Manufacturing & Prototyping
Relatively Inexpensive Rapid Prototyping of Small Parts

Parts with complex three-dimensional shapes and with dimensions up to 8 by 8 by 10 in. (20.3 by 20.3 by 25.4 cm) can be made as unitary pieces of a room- temperature- curing polymer, with relatively little investment in time and money, by a process now in use at Johnson Space Center. The...

Briefs : Manufacturing & Prototyping
Dry Process for Making Polyimide/Carbon-and-Boron-Fiber Tape

A dry process has been invented as an improved means of manufacturing composite prepreg tapes that consist of high- temperature thermoplastic polyimide resin matrices reinforced with carbon and boron fibers. Such tapes are used (especially in the aircraft industry) to fabricate strong,...

Briefs : Information Technology
Modeling and Control of Aerothermoelastic Effects

Aerothermoelasticity comprises those aspects of the dynamics of an aircraft that are caused by flexibility and heating during flight. The concept of aerothermoelasticity is particularly important for hypersonic vehicles that operate at extremely high dynamic pressures. The design requirements for...

Briefs : Information Technology
Algorithms for Haptic Rendering of 3D Objects

Algorithms have been developed to provide haptic rendering of three-dimensional (3D) objects in virtual (that is, computationally simulated) environments. The goal of haptic rendering is to generate tactual displays of the shapes, hardnesses, surface textures, and frictional properties of 3D objects...

Briefs : Information Technology
Prognostics Methodology for Complex Systems

An automatic method to schedule maintenance and repair of complex systems is produced based on a computational structure called the Informed Maintenance Grid (IMG). This method provides solutions to the two fundamental problems in autonomic logistics: (1) unambiguous detection of deterioration or...

Briefs : Materials
Shields for Enhanced Protection Against High-Speed Debris

A report describes improvements over the conventional Whipple shield (two thin, spaced aluminum walls) for protecting spacecraft against high-speed impacts of orbiting debris. The debris in question arises mainly from breakup of older spacecraft. The improved shields include exterior...

Briefs : Materials
Transparent Metal-Salt-Filled Polymeric Radiation Shields

"COR-RA" (colorless atomic oxygen resistant — radiation shield) is the name of a transparent polymeric material filled with x-ray-absorbing salts of lead, bismuth, cesium, and thorium. COR-RA is suitable for use in shielding personnel against bremsstrahlung radiation from electron-beam...

Briefs : Materials
Meshed-Pumpkin Super-Pressure Balloon Design

An improved, lightweight design has been proposed for super-pressure balloons used to carry scientific instruments at high altitudes in the atmosphere of Earth for times as long as 100 days. [A super- pressure balloon is one in which the pressure of the buoyant gas (typically, helium) is kept somewhat...

Briefs : Materials
Corrosion Inhibitors as Penetrant Dyes for Radiography

Liquid/vapor-phase corrosion inhibitors (LVCIs) have been found to be additionally useful as penetrant dyes for neutron radiography (and perhaps also x-radiography). Enhancement of radiographic contrasts by use of LVCIs can reveal cracks, corrosion, and other defects that may be undetectable...

Briefs : Materials
Explicit Pore Pressure Material Model in Carbon-Cloth Phenolic

An explicit material model that uses predicted pressure in the pores of a carbon-cloth phenolic (CCP) composite has been developed. This model is intended to be used within a finite-element model to predict phenomena specific to CCP components of solid-fuel-rocket nozzles subjected...

Briefs : Mechanical & Fluid Systems
Brush-Wheel Samplers for Planetary Exploration

A report proposes brush-wheel mechanisms for acquiring samples of soils from remote planets. In simplest terms, such a mechanism would contain brush wheels that would be counter-rotated at relatively high speed. The mechanism would be lowered to the ground from a spacecraft or other exploratory...

Briefs : Mechanical & Fluid Systems
Lightweight Energy Absorbers for Blast Containers

Kinetic-energy- absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at...

Briefs : Physical Sciences
Tilt-Sensitivity Analysis for Space Telescopes

A report discusses a computational- simulation study of phase- front propagation in the Laser Interferometer Space Antenna (LISA), in which space telescopes would transmit and receive metrological laser beams along 5-Gm interferometer arms. The main objective of the study was to determine the...

Briefs : Physical Sciences
Study of Dislocation-Ordered InₓGa₁₋ₓAs/GaAs Quantum Dots

A report describes an experimental study of dislocation-induced spatial ordering of quantum dots (QDs) comprising nanometer-sized InxGa1–xAs islands surrounded by GaAs. Metastable hetero-epitaxial structures were grown by molecular-beam epitaxy of...

Briefs : Physical Sciences
Alternative Electrochemical Systems for Ozonation of Water

Electrochemical systems that are especially well suited for the small-scale generation of ozone and ozonated water for local use have been invented. These systems can operate with very little maintenance, and the only inputs needed during operation are electric power and water. These...

Briefs : Physical Sciences
Magnetic Field Would Reduce Electron Backstreaming in Ion Thrusters

The imposition of a magnetic field has been proposed as a means of reducing the electron backstreaming problem in ion thrusters.

Electron backstreaming refers to the backflow of electrons into the ion thruster. Back- streaming electrons are accelerated by the large...

Briefs : Software
Software for Improved Extraction of Data From Tape Storage

A computer program has been written to replace the original software of Racal Storeplex Delta tape recorders, which are used at Stennis Space Center. The original software could be activated by a command- line interface only; the present software offers the option of a command-line or...

Briefs : Software
Software for Displaying High-Frequency Test Data

An easy-to-use, intuitive computer program was written to satisfy a need of test operators and data requestors to quickly view and manipulate high-frequency test data recorded at the East and West Test Areas at Marshall Space Flight Center. By enabling rapid analysis, this program makes it...

Briefs : Software
Software To Secure Distributed Propulsion Simulations

Distributed-object computing systems are presented with many security threats, including network eavesdropping, message tampering, and communications middleware masquerading. NASA Glenn Research Center, and its industry partners, has taken an active role in mitigating the security threats...

Briefs : Software
Next-Generation Car Engines Optimized to Improve Gas Mileage

This paper examines the simulation and thermal optimization of a wide-range oxygen sensor, which helps to regulate clean and efficient motor operation. The setup of the finite element model of the oxygen sensor is discussed in detail, along with how the sensor's geometry and material...

Briefs : Photonics/Optics
Interferometer for Measuring Displacement to Within 20 pm

An optical heterodyne interferometer that can be used to measure linear displacements with an error -20 pm has been developed. The remarkable accuracy of this interferometer is achieved through a design that includes (1) a wavefront split that reduces (relative to amplitude splits used...

Briefs : Photonics/Optics
Processing Digital Imagery To Enhance Perceptions of Realism

Multi-scale retinex with color restoration (MSRCR) is a method of processing digital image data based on Edwin Land's retinex (retina + cortex) theory of human color vision. An outgrowth of basic scientific research and its application to NASA's remote-sensing mission, MSRCR is...

Briefs : Photonics/Optics
UV-Enhanced IR Raman System for Identifying Biohazards

An instrumentation system that would include an ultraviolet (UV) laser or light-emitting diode, an infrared (IR) laser, and the equivalent of an IR Raman spectrometer has been proposed to enable noncontact identification of hazardous biological agents and chemicals. In prior research, IR...

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