A concept for obtaining high energy-conversion efficiency in a solar photovoltaic system involves (1) concentration and spectral dispersion of sunlight and (2) use of several types of solar photovoltaic cells, each placed at its optimum location in the spectrum. The spectral dispersion and...

Innovative designs of mufflers for engines of small airplanes have been investigated in an effort to satisfy conflicting demands to maximize the reduction of exhaust noise while minimizing back pressure, size, and weight. Automotive-type muffler designs are not suitable for this purpose because they entail...

In a filing before the U.S. Patent and Trademark Office, the Boeing Company has disclosed a post-processing method for dielectric combiner elements that may reduce the cost of grading dual combiner sets by 90 percent compared to currently produced dielectric types.

An etching solution has been developed for use in removal of silver plating from polymer-based (including composite-material) structural components, the surfaces of which are intended to serve as mirrors and waveguide structures. Such structures are often plated with aluminum, copper,...

A report discusses the design and testing of a laboratory-model arc-jet thruster designed to operate at a nominal power level of 300 W. This thruster is an intermediate product of continuing efforts to develop smaller, lower-power, higher-specific-impulse thrusters for use in a forthcoming generation of small...

An in vitro test that includes the use of two-color flow cytometry has been developed for use in screening of neutrophils for their ability to fight infections. Neutrophils constitute the first line of defense of the human body against infections. Neutrophils engulf invading bacteria in a...

An optical technique for measuring the concentration of soot in air is based on the cavity-ring-down (CRD) principle, which is so named because it involves observation of the decay ("ring-down") of a signal echoing in a cavity. By use of (1) the observed rate of decay and (2) a known...

The Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES) is now using a new general-purpose priority queue data structure called the SPEEDES Qheap for managing its set of pending events in ascending time order. Empirical studies have shown this data structure to...

A unique dual-flow, cold-jet facility has been developed and operated by California Polytechnic State University (Cal Poly) at San Luis Obispo for NASA Dryden Flight Research Center. The facility supports flight research on thrust-vectoring nozzles and thrust-vector control systems. To...

An improved miniature electrostatic sector has been designed for a miniature double-focusing mass spectrometer (see figure). Miniature mass spectrometers are essential components of high-performance, miniature, low-power instruments that are being developed for use in analyzing...

Harmonic drive gearing is recognized by designers for its zero backlash, high gear ratios, and compact design features. A recent development by HD Systems incorporates a large hollow shaft through the actuator, offering many benefits to the machine designer. The FHA hollow shaft actuator series...

An Internet-based software system, called the "Web Interface for Telescience" (WITS), enables geographically dispersed scientists to participate in scientific exploration of remote planets by use of instrumented landers and robotic vehicles called "rovers." WITS at a previous stage of development was...

A proposed wavelength-division-multiplexing (WDM) optical communication system would feature a single optical fiber carrying eight channels of digital data signals. In the original application, the signal in each channel would be a serial digital video-camera output, but the system could...

The NLEDIT computer program implements a generic graphical user interface for the preprocessing of FORTRAN namelist input files. The interface consists of a menu system, a message window, a help system, and data-entry forms. A form is generated for each namelist. The form includes an...

When developing the guidance system of a missile, it is necessary to know the resonant frequencies and mode shapes of the missile in flight. Simulating the free vibration condition in the laboratory, however, is a difficult task, since the required supports can affect the test results.

The Multiple Object Orbital Dynamics Simulation (MOODS) computer program is a general, extensible, easily modifiable, and reusable software system for use in simulating the dynamics of such diverse engineering systems as aircraft, missiles, automobiles, industrial process-control systems,...

The anode separators in rechargeable lithium-ion electrochemical cells that contain carbon lithium-intercalating anodes with copper current collectors would be modified, according to a proposal, to give some protection against the internal short-circuiting that tends to occur during...

Cross-talk in integrated-circuit focal-plane arrays of quantum-well photodetectors (QWIPs) equipped with microlenses would be reduced, according to a proposal, by etching deep trenches into the substrates of these devices. The proposal applies, more specifically, to GaAs-based,...

A method to process optical fiber composed of glass systems has been developed in support of the space shuttle and Space Station programs. This process, known as the Microgravity Fiber-Pulling Apparatus, was designed to operate in a microgravity environment. It has the unique capability to produce heavy-metal...

The performances of large focal-plane arrays of quantum-well infrared photodetectors (QWIPs) would be improved, according to a proposal, by incorporating microlenses. In comparison with a similar QWIP array that lacked microlenses, a QWIP array with microlenses could be made to exhibit less dark current...

The MacWafer™ code computes gravitational and thermal stresses in silicon wafers and uses these results to determine the maximum allowable temperature variation across a wafer, maximum processing temperatures, and maximum allowable heating and cooling rates. This information is of...

Miniature, lightweight, low-power, low-vibration Joule-Thomson Rankine-Cycle refrigerators have been proposed for cooling portable scientific instruments. These refrigerators would be made largely from silicon wafers by micromachining techniques like those used to fabricate integrated circuits....

An acoustic-radiation-pressure phased array (ARPPA) is undergoing development at Lewis Research Center. ARPPAs are envisioned as general-purpose, nonintrusive tools for manipulating both liquids and objects suspended in liquids.

A computer program called "the explicit global-modeling tool" implements a dynamic method of operation by which researchers can (1) determine global flow-path changes that occur during computational simulations of the behaviors of engineering systems; (2) analyze both normal and faulty...

More accurate analyses of adhesive EA946 can now be accomplished using new mathematical models. Tests involving this adhesive (used in the space shuttle's reusable solid-rocket-motor nozzle and other rocket-motor nozzles) indicated that the adhesive is nonlinearly viscoelastic at short equivalent times and...

Several computer programs, denoted collectively as the "CFD Seal Analysis Industrial Codes," have been developed to enable rapid parametric analyses and optimization of designs of a variety of turbomachinery seals. These programs could be used to design the seals that will be needed in...

Quantum-well infrared photodetectors (QWIPs) that are designed to exploit transitions between bound and quasi-bound electron quantum states and that incorporate random reflectors are undergoing development. Focal-plane arrays of such detectors are also undergoing development, all as part of a...

A proposed miniature, electrically tunable, band-pass optical filter would have a Fabry-Perot configuration, but would be designed to trade the high spectral resolution (narrow-band pass) and small tuning range of a traditional Fabry-Perot filter for low spectral resolution (wide-band pass) and...

Structural Analysis/Design (STRAND) and Neural Net Computation (NETCOM) are developmental modular computer programs that exploit the speedup afforded by parallel and neural-network computing to drastically reduce the computation time needed to solve large design-optimization problems....

Inventors at the Cornell Research Foundation have devised a method of selective metallization of high-temperature semiconductors to produce ohmic or rectifying contacts. The process consists of three phases: a lithographic step to define the areas of contact, preparation of the...