8,263 research outputs found

    Lunar material resources: An overview

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    The analysis of returned lunar samples and a comparison of the physical and chemical processes operating on the Moon and on the Earth provide a basis for predicting both the possible types of material resources (especially minerals and rocks) and the physical characteristics of ore deposits potentially available on the Moon. The lack of free water on the Moon eliminates the classes of ore deposits that are most exploitable on Earth; namely, (1) hydrothermal, (2) secondary mobilization and enrichment, (3) precipitation from a body of water, and (4) placer. The types of lunar materials available for exploitation are whole rocks and their contained minerals, regolith, fumarolic and vapor deposits, and nonlunar materials, including solar wind implantations. Early exploitation of lunar material resources will be primarily the use of regolith materials for bulk shielding; the extraction from regolith fines of igneous minerals such as plagioclase feldspars and ilmenite for the production of oxygen, structural metals, and water; and possibly the separation from regolith fines of solar-wind-implanted volatiles. The only element, compound, or mineral, that by itself has been identified as having the economic potential for mining, processing, and return to Earth is helium-3

    Integrability and the Kerr-(A)dS black hole in five dimensions

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    In this note we prove that the Hamilton-Jacobi equation for a particle in the five dimensional Kerr-(A)dS black hole is separable, for arbitrary rotation parameters. As a result we find an irreducible Killing tensor. We also consider the Klein-Gordon equation in this background and show that this is also separable. Finally we comment on extensions and implications of these results.Comment: 4 pages, RevTeX. v2: minus sign typos in eq. (17) and (18) of published version correcte

    Modeling Grain Boundaries using a Phase Field Technique

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    We propose a two dimensional frame-invariant phase field model of grain impingement and coarsening. One dimensional analytical solutions for a stable grain boundary in a bicrystal are obtained, and equilibrium energies are computed. We are able to calculate the rotation rate for a free grain between two grains of fixed orientation. For a particular choice of functional dependencies in the model the grain boundary energy takes the same analytic form as the microscopic (dislocation) model of Read and Shockley.Comment: 4 pages, 2 figure

    AS 444-002: Natl Sec Affairs & Prep Act II

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    AS 222-002: Team & Leadership Fundamental II

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    Multiple-Case Study and Exploratory Analysis of the Implementation of Value-Added Teacher Performance Assessment on Eighth Grade Student Achievement in Ohio, Pennsylvania, and Tennessee

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    The goal of this research was to analyze the academic impact of the implementation of the Value Added Assessment Model. The researcher analyzed the Value Added Assessment Models in the three Value Added Assessment Model states that had implemented the Value Added Assessment Model for more than five years. Additionally, the research was done by analyzing the academic impact as measured by the eighth grade reading NAEP and the eighth grade mathematics NAEP. The researcher paired the three states that had implemented Value Added Assessment Model for more than five years, with three demographically matched states that had not implemented Value Added Assessment Model. The states were matched as follows: Ohio (Value Added Assessment Model implementing state) with Michigan (non Value Added Assessment Model state), Pennsylvania (Value Added Assessment Model implementing state) with Virginia (non Value Added Assessment Model state) and Tennessee (Value Added Assessment Model implementing state) with Georgia (non Value Added Assessment Model state). The mean composite scale score in NAEP from the following categories of students were compared and analyzed: 1) All students 2) White students 3) Black students 4) National School Lunch Program Eligible Students 5) National School Lunch Program Ineligible Students 6) Exceptional Education students. The results of the study indicated that the impact of Value Added Assessment Model on academic impact as measured by the eighth grade reading NAEP and the eighth grade mathematics NAEP was negligible

    AS 222-002 Team & Leadership Fundamental II

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    Basketbrawls Past and Present

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    Many readers have by now heard of the brawl that broke out in the first half of an international basketball match between China and Brazil on October 12 in Henan province. The international “friendly” became increasingly chippy as the Chinese side objected to hard fouls and “dirty” play by the Brazilians. Dissatisfied with the officials’ response, the Chinese team (and its American coach, it should be noted) took matters into its own hands

    Harbin’s Past, Modern Style

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    Historical preservation in China’s ever-growing cities is a challenge. Transformations to Beijing and Shanghai are best documented (for example, as evocatively narrated by Michael Meyer in his Last Days of Old Beijing), but dozens of cities, up and down the coast especially, are witnessing historically rapid change, and a rapid change to their histories
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