3,489 research outputs found

    Optical tracker having overlapping reticles on parallel axes Patent

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    Optical tracker with pair of FM reticles having patterns 90 deg out of phas

    In-flight friction and wear mechanism

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    A unique mechanism developed for conducting friction and wear experiments in orbit is described. The device is capable of testing twelve material samples simultaneously. Parameters considered critical include: power, weight, volume, mounting, cleanliness, and thermal designs. The device performed flawlessly in orbit over an eighteen month period and demonstrated the usefulness of this design for future unmanned spacecraft or shuttle applications

    Metal Oxide Silicon /MOS/ transistors protected from destructive damage by wire

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    Loop of flexible, small diameter, nickel wire protects metal oxide silicon /MOS/ transistors from a damaging electrostatic potential. The wire is attached to a music-wire spring, slipped over the MOS transistor case, and released so the spring tensions the wire loop around all the transistor leads, shorting them together. This allows handling without danger of damage

    Focus drive mechanism for the IUE scientific instrument

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    A compact, lightweight mechanism was developed for in-orbit adjustment of the position of the secondary mirror (focusing) of the International Ultraviolet Explored telescope. This device is a linear drive with small (.0004 in.) and highly repeatable step increments. Extremely close tolerances are also held in tilt and decentering. The unique mechanization is described with attention to the design details that contribute to positional accuracy. Lubrication, materials, thermal considerations, sealing, detenting against launch loads, and other features peculiar to flight hardware are discussed. The methods employed for mounting the low expansion quartz mirror with minimum distortion are also given

    A new approach to long-life noncontacting electromechanical devices

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    Brushless dc motors are finding increasing application in space. Likewise, with the advent of the light emitting diode, noncontacting encoders are gradually replacing sliding contact types. The direct drive concept has proved its merit and is now the preferred approach for tape recorders and low to moderate torque instrument drives. The final step in this evolution is the magnetic bearing, which now appears feasible for several applications. Where it can be applied in a totally noncontacting system, life and reliability will be a function of the electronic controls, where redundancy, derating, and quality assurance approaches virtually assure the desired lifetime and failure rate

    VLA Observations of the Infrared Dark Cloud G19.30+0.07

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    We present Very Large Array observations of ammonia (NH3) (1,1), (2,2), and CCS (2_1-1_0) emission toward the Infrared Dark Cloud (IRDC) G19.30+0.07 at ~22GHz. The NH3 emission closely follows the 8 micron extinction. The NH3 (1,1) and (2,2) lines provide diagnostics of the temperature and density structure within the IRDC, with typical rotation temperatures of ~10 to 20K and NH3 column densities of ~10^15 cm^-2. The estimated total mass of G19.30+0.07 is ~1130 Msun. The cloud comprises four compact NH3 clumps of mass ~30 to 160 Msun. Two coincide with 24 micron emission, indicating heating by protostars, and show evidence of outflow in the NH3 emission. We report a water maser associated with a third clump; the fourth clump is apparently starless. A non-detection of 8.4GHz emission suggests that the IRDC contains no bright HII regions, and places a limit on the spectral type of an embedded ZAMS star to early-B or later. From the NH3 emission we find G19.30+0.07 is composed of three distinct velocity components, or "subclouds." One velocity component contains the two 24 micron sources and the starless clump, another contains the clump with the water maser, while the third velocity component is diffuse, with no significant high-density peaks. The spatial distribution of NH3 and CCS emission from G19.30+0.07 is highly anti-correlated, with the NH3 predominantly in the high-density clumps, and the CCS tracing lower-density envelopes around those clumps. This spatial distribution is consistent with theories of evolution for chemically young low-mass cores, in which CCS has not yet been processed to other species and/or depleted in high-density regions.Comment: 29 pages, 9 figures, accepted for publication by ApJ. Please contact the authors for higher resolution versions of the figure

    Research Notes : United States : Genetic linkage information

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    Descriptions of the genetic traits indicated by the gene symbols in Table 1 are given in the chapter on Qualitative Genetics in the Soybean Monograph (Bernard and Weiss, 1973). Recombination was calculated on F2 data us-ing the product method as described by Irrnner and Henderson (1943). All link-age combinations tested were found to follow independent assortment except the combination ln and p2

    Research Notes: Vegetative Propagation of Soybeans

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    During the course of genetic studies of possible linkage associations involving factors controlling nodulation response in soybeans, we found it desirable to increase the size of the F2 population produced in the greenhouse during the winter. We endeavored to do this by vegetatively propagating the F1 hybrid plants for use in seed production. We visualize that vegetative propagation would also be useful for other purposes: (1) maintaining aneuploids which segregate at meiosis, and (2) providing propagules which may be subjected to different photoperiod regimes, thus providing coincidence of flowering in crosses of uncertain maturity when little seed is available
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