6,681 research outputs found

    Potential of Interplanetary Torques and Solar Modulation for Triggering Terrestrial Atmospheric and Lithospheric Events

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    The Sun is forced into an orbit around the barycenter of the solar system because of the changing mass distribution of the planets. Solar-planetary-lunar dynamic relationships may form a new basis for understanding and predicting cyclic solar forcing functions on the Earth's climate.Comment: Invited Paper at the Fourth UN/ESA Workshop on Basic Space Science, Cairo, Egypt, July 1994. 7 pages LaTeX. Accepted for publication in the journal Earth, Moon, and Planet

    Vibrational relaxation measurements in CO2 USING an induced fluorescence technique

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    Vibrational relaxation measurements in carbon dioxide using induced infrared fluorescence techniqu

    Recent development in the design, testing and impact-damage tolerance of stiffened composite panels

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    Structural technology of laminated filamentary-composite stiffened-panel structures under combined inplane and lateral loadings is discussed. Attention is focused on: (1) methods for analyzing the behavior of these structures under load and for determining appropriate structural proportions for weight-efficient configurations; and (2) effects of impact damage and geometric imperfections on structural performance. Recent improvements in buckling analysis involving combined inplane compression and shear loadings and transverse shear deformations are presented. A computer code is described for proportioning or sizing laminate layers and cross-sectional dimensions, and the code is used to develop structural efficiency data for a variety of configurations, loading conditions, and constraint conditions. Experimental data on buckling of panels under inplane compression is presented. Mechanisms of impact damage initiation and propagation are described

    Infrared emission spectrum and potentials of 0u+0_u^+ and 0g+0_g^+ states of Xe2_2 excimers produced by electron impact

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    We present an investigation of the Xe2_{2} excimer emission spectrum observed in the near infrared range about 7800 cm1^{-1} in pure Xe gas and in an Ar (90%) --Xe (10%) mixture and obtained by exciting the gas with energetic electrons. The Franck--Condon simulation of the spectrum shape suggests that emission stems from a bound--free molecular transition never studied before. The states involved are assigned as the bound (3)0u+(3)0_{u}^{+} state with 6p[1/2]06p [1/2]_{0} atomic limit and the dissociative (1)0g+(1)0_{g}^{+} state with 6s[3/2]16s [3/2]_{1} limit. Comparison with the spectrum simulated by using theoretical potentials shows that the dissociative one does not reproduce correctly the spectrum features.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

    A Method to Allow Software Detection of Multiple Different Chassis Types That Use a Common PCA

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    Many computer system designs today implement a common printed circuit board assembly that is used in more than one mechanical chassis. This invention describes a design method that allows software to identify in which chassis the PCA has been installed. The system software is able to determine the chassis type be detecting a set of mounting screw connections that are unique for each particular chassis

    Pittsburgh\u27s Mt. Lebanon Tunnels- Case History

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    Discussions of basic design philosophy and comparison of alternative contract bid options are presented. Also discussed are descriptions of field monitoring activities with respect to the construction methods, ground response, installation of materials and their performance. Finally, conclusions are reached relative to the NATM philosophy as applied to this project and its place as a design process within the context of United States underground construction practice

    Resonance Inspection for Quality Control

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    Resonant Inspection (RI)* is an important new technique for non-destructive evaluation of manufactured parts. RI mechanically vibrates a part and detects defects based on changes in the pattern of vibrational resonances. RI measures the “whole body” structural response of the part rather than scanning for defects, as do most other NDE techniques. As a result it is accurate, fast, inexpensive and requires no human judgment, so it can be used for 100% inspection. However, since RI infers the presence of a defect from the resonant pattern of the whole part, up - front engineering is required to develop a detection algorithm that correlates the changes in resonance pattern to the presence of defects of interest

    Atmospheric extinction coefficients in the Ic\mathrm{I_c} band for several major international observatories: Results from the BiSON telescopes, 1984 to 2016

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    Over 30 years of solar data have been acquired by the Birmingham Solar Oscillations Network (BiSON), an international network of telescopes used to study oscillations of the Sun. Five of the six BiSON telescopes are located at major observatories. The observational sites are, in order of increasing longitude: Mount Wilson (Hale) Observatory (MWO), California, USA; Las Campanas Observatory (LCO), Chile; Observatorio del Teide, Iza\~{n}a, Tenerife, Canary Islands; the South African Astronomical Observatory (SAAO), Sutherland, South Africa; Carnarvon, Western Australia; and the Paul Wild Observatory, Narrabri, New South Wales, Australia. The BiSON data may be used to measure atmospheric extinction coefficients in the Ic\mathrm{I_c} band (approximately 700-900 nm), and presented here are the derived atmospheric extinction coefficients from each site over the years 1984 to 2016.Comment: 15 pages, 10 figures, 4 tables. Accepted by Astronomical Journal: 2017 July 2
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