Tech Briefs

Tunable HTS/Ferroelectric Microstrip Band-Pass Filters

These filters are designed for operation at temperatures less than about 77 K. Electrically tunable microstrip two-pole band-bass filters for a center frequency near 19 GHz and a 4-percent bandwidth have been designed, fabricated, and demonstrated to be functional. These filters are suitable for use in the front ends of K-band communication receivers that operate at low temperatures.

Posted in: Briefs, Electronics & Computers

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Reducing Methanol Crossover in CH3OH-Fuel-Cell Membranes

Perfluorosulfonic acid-based membranes are impregnated with poly(styrene/divinylbenzene). Improved polymer electrolyte membranes for direct methanol fuel cells can be made by impregnating the baseline membrane material with cross-linked polystyrene (a copolymer of styrene and divinylbenzene). The baseline membrane material is a perfluorosulfonic acid-based hydrophilic, proton-conducting ion-exchange polymer sold under the trade name "Nafion". The principal benefit afforded by the impregnation is a reduction in permeability by methanol; this translates to less crossover of methanol in molecular form (denoted "methanol crossover" for short). Methanol crossover is undesired because it wastes fuel and thereby degrades fuel-cell performance.

Posted in: Briefs, TSP, Materials

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Inflatable Wing Leading Edges for High Lift and Deicing

The incidence of stall accidents could be reduced. Computational simulations and wind-tunnel tests have demonstrated the feasibility of using inflatable boots on the leading edges of airplane wings, both as devices to increase lift and as pneumatic deicing actuators. Assuming success in further research and development, the first applications would likely occur as retrofits to single- and twin-engine airplanes in general aviation (GA). Later, corporate and commuter turboprop airplanes would be included. The eventual incorporation of these boots into new GA airplane designs would be even more desirable because the boots could be integrated with overall wing structures to provide laminar flow in cruise.

Posted in: Briefs, TSP, Mechanical Components, Mechanics

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Expert System To Develop Job Standards

The Job Standards Development System is a user-friendly expert system that (1) helps users select an appropriate work measurement methodology to develop job standards (or the less formal job time estimates) and (2) leads the users through the steps necessary to use a work time estimating technique to develop job standards for long-duration, low-repetition work. The computer program comprises three parts, the first being a system-administration subprogram, in which an administrator sets values of parameters that are not changeable by a job standards developer. The second part is a subprogram that assists the job standards developer in the selection of an appropriate work measurement technique. The third part supports the application of a work time and resource requirement estimating technique that relies on domain expertise to describe human work, collects work time and resource requirement data from the domain expert, and computes a job standard. The program is expected to be useful for the management of organizations devoted to performing functions consisting of long-duration, low-repetition work. Illustrations of this type include facility and equipment maintenance and the knowledge work of service firms and federal, state, and local governments. The program is written for use with the Windows operating systems on IBM PC and compatible computers.

Posted in: Briefs, Information Sciences

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Further Developments in Web Interactive Training

Displays, simulations, and quizzes are customized for each trainee. Three innovative computer programs for training and testing personnel at Kennedy Space Center have been developed under the aegis of the Web Interactive Training (WIT) project. The WIT project exploits the capabilities afforded by the Internet and by state-of-the-art multimedia data-presentation techniques. The World Wide Web is used to deliver training from server computers to client desktop computers on demand. Training can involve multimedia data of various types (text, audio, graphics, and animated video images). Training can be interactive, enabling trainees to tailor lessons to their individual needs; a trainee can select a lesson or segment any time, anywhere, and can repeat a segment as many times as necessary. Interactivity can also be exploited to provide for testing and recording of a trainee's progress.

Posted in: Briefs, TSP, Information Sciences

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Using Narrow-Band Data Links in Locating Lightning Strikes

Electric-field waveforms are preprocessed to extract selected characteristics. A method of preprocessing lightning-measurement waveforms has been devised to reduce the bandwidth needed to transmit data for computing the locations of lightning strikes. The method is used in a system in which electric fields and electric-field derivatives induced by lightning are measured at remote stations and the measurement data are transmitted to a central station. At the central station, the location of each lightning strike is computed from the known positions of the stations, the speed of light, and the differences among times of arrival of common waveform features at the remote stations. Prior to the development of the present method, in order to achieve a required spatial resolution of tens of meters, it was necessary to transmit full measurement data from each remote station to the central station in real time at a bandwidth of 10 MHz.

Posted in: Briefs, Electronics & Computers

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Centralized Electronic Reporting of Material-Science Tasks

Expensive and time-consuming distribution of, and searches among, paper documents are no longer necessary. The Materials Science Division (MSD) at Kennedy Space Center is developing a computer system to maintain a material-science data base coupled with a user-friendly interface on the World Wide Web. The system is designed to eliminate the need for time-consuming and expensive distribution of, and searches among, paper documents.

Posted in: Briefs, Electronics & Computers

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