Estimation of Apollo lunar dust transport using optical extinction measurements

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

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)

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

SUBACUTE MALIGNANT PEMPHIGUS WITH EXTENSIVE BULLAE: (Pemphigus Subaigu Malin à Bulles Extensives, Brocq)

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Narrow Technihadron Production at the First Muon Collider

In modern technicolor models, there exist very narrow spin-zero and spin-one neutral technihadrons---$pi^0_T$, $rho^0_T$ and $omega_T$---with masses of a few 100 GeV. The large coupling of $\pi^0_T$ to $\mu^+\mu^-$, the direct coupling of $rho^0_T$ and $omega_T$ to the photon and $Z^0$, 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

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

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

Lagrangian Trajectory Modeling of Lunar Dust Particles

Apollo landing videos shot from inside the right LEM window, provide a quantitative measure of the characteristics and dynamics of the ejecta spray of lunar regolith particles beneath the Lander during the final 10 [m] or so of descent. Photogrammetry analysis gives an estimate of the thickness of the dust layer and angle of trajectory. In addition, Apollo landing video analysis divulges valuable information on the regolith ejecta interactions with lunar surface topography. For example, dense dust streaks are seen to originate at the outer rims of craters within a critical radius of the Lander during descent. The primary intent of this work was to develop a mathematical model and software implementation for the trajectory simulation of lunar dust particles acted on by gas jets originating from the nozzle of a lunar Lander, where the particle sizes typically range from 10 micron to 500 micron. The high temperature, supersonic jet of gas that is exhausted from a rocket engine can propel dust, soil, gravel, as well as small rocks to high velocities. The lunar vacuum allows ejected particles to travel great distances unimpeded, and in the case of smaller particles, escape velocities may be reached. The particle size distributions and kinetic energies of ejected particles can lead to damage to the landing spacecraft or to other hardware that has previously been deployed in the vicinity. Thus the primary motivation behind this work is to seek a better understanding for the purpose of modeling and predicting the behavior of regolith dust particle trajectories during powered rocket descent and ascent