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Enhancing Spin Filters by Use of Bulk Inversion Asymmetry

Current spin polarization could be maximized through appropriate choice of collection angle. Theoretical calculations have shown that the degrees of spin polarization in proposed nonmagnetic semiconductor resonant tunneling spin filters could be increased through exploitation of bulk inversion asymmetry (BIA). These enhancements would be effected through suitable orientation of spin collectors (or spin- polarization- inducing lateral electric fields), as described below.

Posted in: Physical Sciences, Briefs

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Measuring Dynamic Transfer Functions of Cavitating Pumps

Flow and pressure perturbations are imposed; transfer functions are computed from responses. A water-flow test facility has been built to enable measurement of dynamic transfer functions (DTFs) of cavitating pumps and of inducers in such pumps. Originally, the facility was intended for use in an investigation of the effects of cavitation in a rocket-engine low-pressure oxygen turbopump. The facility can also be used to measure DTFs of cavitating pumps in general.

Posted in: Mechanical Components, Briefs

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Robot Would Climb Steep Terrain

This walking robot could even climb under overhangs. The figure depicts the steep terrain access robot (STAR) — a walking robot that has been proposed for exploring steep terrain on remote planets. Robots based on the STAR concept could also be used on steep terrain on Earth for diverse purposes that could include not only scientific exploration but also military reconnaissance and search-and-rescue operations.

Posted in: Mechanical Components, Briefs

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Advanced Reference Counting Pointers for Better Performance

A computer program implements reference counting pointers (RCPs) that are lock-free, thread-safe, async-safe, and operational on a multiprocessor computer. RCPs are powerful and convenient means of managing heap memory in C++ software. Most prior RCP programs use locks to ensure thread safety and manage concurrency. The present program was developed in a continuing effort to explore ways of using the C++ programming language to develop safety-critical and mission-critical software.

Posted in: Information Sciences, Briefs

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NASA Enterprise Visual Analysis

NASA Enterprise Visual Analysis (NEVA) is a computer program undergoing development as a successor to Launch Services Analysis Tool (LSAT), formerly known as Payload Carrier Analysis Tool (PCAT). NEVA facilitates analyses of proposed configurations of payloads and packing fixtures (e.g. pallets) in a spaceshuttle payload bay for transport to the International Space Station. NEVA reduces the need to use physical models, mock-ups, and full-scale ground support equipment in performing such analyses. Using NEVA, one can take account of such diverse considerations as those of weight distribution, geometry, collision avoidance, power requirements, thermal loads, and mechanical loads.

Posted in: Information Sciences, Briefs

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Tracking-Data-Conversion Tool

A computer program denoted Tracking Data Delivery Software Orbit Data File (TDDSODF) converts deep- space- radiocommunication spacecraft-tracking data from a currently used file format known in the art as “TRK-2-34” to a legacy format denoted “TRK-2-18.” TDDSODF reads standard formatted data units (SFDUs) of several TRK-2-34 types and processes them into an orbit data file (ODF) containing data of one or more of several different TRK-2-18 types. TDDSODF offers the user the following options:

Posted in: Information Sciences, Briefs

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Efficient Mosaicking of Spitzer Space Telescope Images

A parallel version of the MOPEX software, which generates mosaics of infrared astronomical images acquired by the Spitzer Space Telescope, extends the capabilities of the prior serial version. In the parallel version, both the input image space and the output mosaic space are divided among the available parallel processors. This is the only software that performs the point- source detection and the rejection of spurious imaging effects of cosmic rays required by Spitzer scientists. This software includes components that implement outlier-detection algorithms that can be fine-tuned for a particular set of image data by use of a number of adjustable parameters.

Posted in: Information Sciences, Briefs

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