4,359 research outputs found

    Estimation of Apollo lunar dust transport using optical extinction measurements

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    A technique to estimate mass erosion rate of surface soil during landing of the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume interaction is proposed and tested. The erosion rate is proportional to the product of the second moment of the lofted particle size distribution N(D), and third moment of the normalized soil size distribution S(D), divided by the integral of S(D)D^2/v(D), where D is particle diameter and v(D) is the vertical component of particle velocity. The second moment of N(D) is estimated by optical extinction analysis of the Apollo cockpit video. Because of the similarity between mass erosion rate of soil as measured by optical extinction and rainfall rate as measured by radar reflectivity, traditional NWS radar/rainfall correlation methodology can be applied to the lunar soil case where various S(D) models are assumed corresponding to specific lunar sites.Comment: Acta Geophysica 201

    WWII and Long Run Convergence in the OECD

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    Existing evidence for unconditional convergence in the OECD is mixed, and depends largely on whether time series or cross sectional methods are used. In this paper we reconsider the evidence for unconditional convergence by dividing the long run data into several subperiods. We use a two stage approach in this work. We first model the growth rate of output directly and use this model to estimate the long-run growth rate for the countries in our sample. We then use the estimates of long-run growth in output to test for unconditional convergence and to test for equality of long-run growth across countries. GLS is used to explicitly take into account the sampling uncertainty inherent in our estimates of the long-run growth rate we found in the first stage of the process. The results show strong evidence for unconditional convergence in the post WWII period 1951-1974, but no evidence of convergence in the periods preceding or following this period. Moreover, it is di±cult to reject the hypothesis that most of the countries in our sample had the same growth rate outside of this period. Thus find little evidence to suggest that absolute convergence has been a continuous long run process, and some evidence for the view that national policies mainly affect income levels rather than growth rateGrowth, Convergence, Technological Change

    A Note on the Discovery of a Rare Bat Flea in Ohio (Siphonaptera: Ischnopsyllidae)

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    Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbus 1

    Narrow Technihadron Production at the First Muon Collider

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    In modern technicolor models, there exist very narrow spin-zero and spin-one neutral technihadrons---piT0pi^0_T, rhoT0rho^0_T and omegaTomega_T---with masses of a few 100 GeV. The large coupling of πT0\pi^0_T to μ+μ−\mu^+\mu^-, the direct coupling of rhoT0rho^0_T and omegaTomega_T to the photon and Z0Z^0, and the superb energy resolution of the First Muon Collider may make it possible to resolve these technihadrons and produce them at extraordinarily large rates.Comment: 11 pages, latex, including 2 postscript figure

    Spatial and Temporal Extrapolation of Disdrometer Size Distributions Based on a Lagrangian Trajectory Model of Falling Rain

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    Methodologies to improve disdrometer processing, loosely based on mathematical techniques common to the field of particle flow and fluid mechanics, are examined and tested. The inclusion of advection and vertical wind field estimates appears to produce significantly improved results in a Lagrangian hydrometeor trajectory model, in spite of very strict assumptions of noninteracting hydrometeors, constant vertical air velocity, and time independent advection during a radar scan time interval. Wind field data can be extracted from each radar elevation scan by plotting and analyzing reflectivity contours over the disdrometer site and by collecting the radar radial velocity data to obtain estimates of advection. Specific regions of disdrometer spectra (drop size versus time) often exhibit strong gravitational sorting signatures, from which estimates of vertical velocity can be extracted. These independent wind field estimates can be used as initial conditions to the Lagrangian trajectory simulation of falling hydrometeors.Comment: 25 pages, 15 figures, 4 tables. Submitted to The Open Atmospheric Science Journal, http://www.bentham.org/open/toascj

    Cornbread & Sushi: a Journey Through the Rural South

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    This book is a collaborative product of the Cornbread & Sushi Seminar at Wofford College 2005-2006 The seminar was led by the faculty members John Lane and Deno Trakas. The contributors (including Wofford students, faculty, and staff, and Southern authors) are: Austin Baker, Elizabeth Bethea, Butch Clay, Hal Crowther, Ivy Farr, Tom Franklin, William Gay, Frye Gaillard, Steve Harvey, Casey Lambert, Martin Lammon, John Lane, Lewis Lovett, Trish Makres, Karen Sayler McElmurray, Larry McGehee, Jim Morgan, Mary Mungo, Mark Olencki, Wilson Peden, Jason Rains, Hallie Sessoms, Ron Rash, Dori Sanders, Bettie Sellers, George Singleton, Lee Smith, Deno Trakas, Laura Vaughn, and Leland Wood.https://digitalcommons.wofford.edu/collegebooks/1014/thumbnail.jp

    Can government policies increase national long-run growth rates?

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    We obtain time series estimates of the long run growth rates of 17 OECD countries, and test the hypothesis that these are the same across countries. We find that we cannot reject this hypothesis for the first and last three decades of the 20th century. We conclude that: (i) there are few, if any, feasible policies available that have a significant effect on long run growth rates, and; (ii) any policies that can raise national growth rates must be international in scope. The results therefore have bleak implications for the ability of countries to affect their long run growth rates
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