4,290 research outputs found

    A survey of laser lightning rod techniques

    Get PDF
    The work done to create a laser lightning rod (LLR) is discussed. Some ongoing research which has the potential for achieving an operational laser lightning rod for use in the protection of missile launch sites, launch vehicles, and other property is discussed. Because of the ease with which a laser beam can be steered into any cloud overhead, an LLR could be used to ascertain if there exists enough charge in the clouds to discharge to the ground as triggered lightning. This leads to the possibility of using LLRs to test clouds prior to launching missiles through the clouds or prior to flying aircraft through the clouds. LLRs could also be used to probe and discharge clouds before or during any hazardous ground operations. Thus, an operational LLR may be able to both detect such sub-critical electrical fields and effectively neutralize them

    SeaWiFS technical report series. Volume 10: Modeling of the SeaWiFS solar and lunar observations

    Get PDF
    Post-launch stability monitoring of the Sea-viewing Wide Field-of-view Sensor (SeaWifs) will include periodic sweeps of both an onboard solar diffuser plate and the moon. The diffuser views will provide short-term checks and the lunar views will monitor long-term trends in the instrument's radiometric stability. Models of the expected sensor response to these observations were created on the SeaWiFS computer at the National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC) using the Interactive Data Language (IDL) utility with a graphical user interface (GUI). The solar model uses the area of intersecting circles to simulate the ramping of sensor response while viewing the diffuser. This model is compared with preflight laboratory scans of the solar diffuser. The lunar model reads a high-resolution lunar image as input. The observations of the moon are simulated with a bright target recovery algorithm that includes ramping and ringing functions. Tests using the lunar model indicate that the integrated radiance of the entire lunar surface provides a more stable quantity than the mean of radiances from centralized pixels. The lunar model is compared to ground-based scans by the SeaWiFS instrument of a full moon in December 1992. Quality assurance and trend analyses routines for calibration and for telemetry data are also discussed

    A Paleocene Paleomagnetic Pole from the Gringo Gulch Volcanics, Santa Cruz County, Arizona

    Get PDF
    Paleomagnetic data from 25 sites (5 samples per site) in andesite flows of the Gringo Gulch Volcanics in Santa Cruz County, Arizona, were analyzed to determine a lower Paleocene paleomagnetic pole. Alternating - field demagnetization to 500 oe peak field was sufficient to erase secondary viscous components. The mean direction of magnetization (inclination = -58.80, declination = 167.5 °) was obtained by averaging the site mean directions of the 25 sites, which are all reversed. The resultant lower Paleocene pole position is at lat. 77.0 °N, lon. 201.0 °E (dp = 1.2 °, dm = 1.7 °)

    Working Futures 2017-2027 : Long-run labour market and skills projections headline report

    Get PDF
    This report provides a concise overview of Working Futures 2017-2027 results for the UK. It presents historical trends and future prospects by sector for the UK and its constituent nations and the English regions. The prime focus of Working Futures is on the demand for skills as measured by employment by occupation and qualification, although the supply side is also considered. Its prime objective is to provide useful labour market information that can help to inform policy development and strategy around skills, careers and employment, for both policy makers and a much wider audience. The results are intended to provide a sound statistical foundation for reflection and debate among all those with an interest in the demand for and supply of skills. It is aimed at the general reader and focuses on the key messages from this very detailed study. It complements the more detailed outputs and results from the project available from the gov.uk website2 and cover sectors, occupations, geography and qualifications

    Mechanical Properties of Small Clear Specimens and Visually Graded Lumber from Living and Spruce Budworm-Killed Balsam Fir

    Get PDF
    Small clear specimens from living balsam fir and from spruce budworm-killed balsam fir dead 3 months, 12 months, and 22 months were tested in bending and compression perpendicular to the grain. Results indicated that modulus of rupture (MOR) of specimens from budworm-killed trees dead 3 months or more was significantly lower than MOR of specimens from living trees. Modulus of elasticity (MOE) appeared to be less sensitive to changes in budworm-killed material than MOR. Stress at the proportional limit for compression perpendicular to the grain was significantly lower for specimens from trees dead 22 months than for specimens from living trees. Both MOE and MOR in bending were determined for visually graded nominal 2- by 4-inch lumber from living and spruce budworm-killed balsam fir dead 12 months and 22 months. Average MOE values for living balsam fir were 1.274 x 106 psi, 1.217 x 106 psi, and 1.175 x 106 psi for Construction, Standard and Utility grades, respectively. Average MOR values for the same grades of living material were 4,699 psi, 4,684 psi, and 4,352 psi, respectively. Average MOE and MOR for Utility grade lumber from both spruce budworm-killed categories were not significantly different from the average MOE and MOR for living balsam fir. Statistical analyses of the MOE and MOR data for Construction and Standard grades of budworm-killed lumber were not performed due to the small sample sizes
    • …
    corecore