Tech Briefs

World Wind 3D Earth Viewing

World Wind allows users to zoom from satellite altitude down to any place on Earth, leveraging high-resolution LandSat imagery and SRTM (Shuttle Radar Topography Mission) elevation data to experience Earth in visually rich 3D. In addition to Earth, World Wind can also visualize other planets, and there are already comprehensive data sets for Mars and the Earth’s moon, which are as easily accessible as those of Earth.

Posted in: Briefs, Software, Imaging and visualization, Satellite communications, Human machine interface (HMI)

JavaGenes Molecular Evolution

JavaGenes is a general-purpose, evolutionary software system written in Java. It implements several versions of a genetic algorithm, simulated annealing, stochastic hill climbing, and other search techniques. This software has been used to evolve molecules, atomic force field parameters, digital circuits, Earth Observing Satellite schedules, and antennas. This version differs from version 0.7.28 in that it includes the molecule evolution code and other improvements. Except for the antenna code, JaveGenes is available for NASA Open Source distribution.

Posted in: Briefs, Software, Mathematical models, Antennas, Computer software and hardware, Electronic control systems

Accounting for Uncertainties in Strengths of SiC MEMS Parts

Fracture strength of a part can be predicted as one statistical distribution.

A methodology has been devised for accounting for uncertainties in the strengths of silicon carbide structural components of microelectromechanical systems (MEMS). The methodology enables prediction of the probabilistic strengths of complexly shaped MEMS parts using data from tests of simple specimens. This methodology is intended to serve as a part of a rational basis for designing SiC MEMS, supplementing methodologies that have been borrowed from the art of designing macroscopic brittle material structures.

Posted in: Briefs, TSP, Materials, Finite element analysis, Microelectromechanical devices, Prognostics, Materials properties, Silicon alloys

Lithium Dinitramide as an Additive in Lithium Power Cells

This inorganic additive appears to act as a superior SEI promoter.

Lithium dinitramide, LiN(NO2)2 has shown promise as an additive to nonaqueous electrolytes in rechargeable and non-rechargeable lithium-ion-based electrochemical power cells. Such non-aqueous electrolytes consist of lithium salts dissolved in mixtures of organic ethers, esters, carbonates, or acetals. The benefits of adding lithium dinitramide (which is also a lithium salt) include lower irreversible loss of capacity on the first charge/discharge cycle, higher cycle life, lower self-discharge, greater flexibility in selection of electrolyte solvents, and greater charge capacity.

Posted in: Briefs, Materials, Battery cell chemistry, Lithium-ion batteries

Ion-Conducting Organic/Inorganic Polymers

Properties can be tailored through a choice of starting alkoxysilane and diamine ingredients.

Ion-conducting polymers that are hybrids of organic and inorganic moieties and that are suitable for forming into solidelectrolyte membranes have been invented in an effort to improve upon the polymeric materials that have been used previously for such membranes. Examples of the prior materials include perfluorosulfonic acid-based formulations, polybenzimidazoles, sulfonated polyetherketone, sulfonated naphthalenic polyimides, and polyethylene oxide (PEO)-based formulations. Relative to the prior materials, the polymers of the present invention offer greater dimensional stability, greater ease of formation into mechanically resilient films, and acceptably high ionic conductivities over wider temperature ranges. Devices in which films made of these ion-conducting organic/ inorganic polymers could be used include fuel cells, lithium batteries, chemical sensors, electrochemical capacitors, electrochromic windows and display devices, and analog memory devices.

Posted in: Briefs, TSP, Materials, Performance upgrades, Conductivity, Materials properties

MoO₃ Cathodes for High-Temperature Lithium Thin-Film Cells

Cycle lives of these cathodes exceed those of LiCoO2 and LiMn2O4 cathodes.

MoO3 has shown promise as a cathode material that can extend the upper limit of operating temperature of rechargeable lithium thin-film electrochemical cells. Cells of this type are undergoing development for use as energy sources in cellular telephones, wireless medical sensors, and other, similarly sized portable electronic products. The LiCoO2 and LiMn2O4 cathodes heretofore used in these cells exhibit outstanding cycle lives (of the order of hundreds of thousands of cycles) at room temperature, but operation at higher temperatures reduces their cycle lives substantially: for example, at a temperature of 150 °C, cells containing LiCoO2 cathodes lose half their capacities in 100 charge/discharge cycles.

Posted in: Briefs, TSP, Materials, Battery cell chemistry, Lithium-ion batteries, Thermal testing

Motorcycle Design Optimized With Finite-Element Software

Sierra Design Engineering, Mount Aukum, California BUB Enterprises, Grass Valley, California;


ALGOR, Inc., Pittsburgh, Pennsylvania

FEA software was used to analyze key components of a racing streamliner.

A streamliner motorcycle designed and built by Sierra Design Engineering and BUB Enterprises achieved a new world-record speed of 350.884 miles per hour last year at the Bonneville Salt Flats in Utah. In 1989, the original engine and transmission were designed by Joe Harralson of Sierra Design Engineering, with the rest of the streamliner being designed and built by BUB Enterprises.

Posted in: Briefs, Mechanical Components, Mechanics, Design processes, Finite element analysis, Two or three wheeled vehicles

Counterrotating-Shoulder Mechanism for Friction Stir Welding

The weights and costs of fixtures for holding workpieces could be reduced.

A counterrotating-shoulder mechanism has been proposed as an alternative to the mechanism and fixtures used in conventional friction stir welding. The mechanism would internally react most or all of the forces and torques exerted on the workpiece, making it unnecessary to react the forces and torques through massive external fixtures.

Posted in: Briefs, Manufacturing & Prototyping, Adaptive control, Manufacturing equipment and machinery, Welding

Strain Gauges Indicate Differential-CTE-Induced Failures

Failures are indicated by changes in slopes of strain versus temperature.

A method of detecting mechanical failure induced by variation in temperature at an adhesive bond between two materials that have different coefficients of thermal expansion (CTEs) involves monitoring of strain-gauge readings. This method can be regarded as an exploitation of the prior observation that the readings of strain gauges commonly used in tensile and compressive testing of material specimens include features indicative of incremental failures in the specimens. In this method, one or more strain gauges are bonded to either or both of the two materials near the bond between the materials. (The adhesive used to bond the strain gauges would not ordinarily be the same as the one used to bond the two materials). Then strain-gauge readings are recorded as the temperature of the materials is varied through a range of interest. Any significant discontinuity in the slope of the resulting strain-versus- temperature curve(s) is taken to be a qualitative indication of a failure of the bond between the two materials and/or a failure within one of the materials in the vicinity of the bond.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Failure modes and effects analysis, Joining, Adhesives and sealants, Composite materials, Test equipment and instrumentation, Thermal testing

Antibodies Against Three Forms of Urokinase

These antibodies can be used to measure small quantities of three molecular forms of urokinase.

Antibodies that bind to preselected regions of the urokinase molecule have been developed. These antibodies can be used to measure small quantities of each of three molecular forms of urokinase that could be contained in microsamples or conditioned media harvested from cultures of mammalian cells. Previously available antibodies and assay techniques do not yield both clear distinctions among, and measurements of, all three forms.

Posted in: Briefs, Bio-Medical, Medical, Biological sciences, Diseases, Test procedures

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