1,674 research outputs found

    Vanishing Fe 3d orbital moments in single-crystalline magnetite

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    We show detailed magnetic absorption spectroscopy results of an in situ cleaved high quality single crystal of magnetite. In addition the experimental setup was carefully optimized to reduce drift, self absorption, and offset phenomena as far as possible. In strong contradiction to recently published data, our observed orbital moments are nearly vanishing and the spin moments are quite close to the integer values proposed by theory. This very important issue supports the half metallic full spin polarized picture of magnetite.Comment: 7 pages, 4 figure

    Higher order finite element analysis of thick composite laminates

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    A higher order, sub-parametric, laminated, 3D solid finite element was used for the analysis of very thick laminated composite plates. The geometry of this element is defined by four nodes in the X-Y plane which define a prism of material through the thickness of the laminate. There are twenty-four degrees of freedom at each node; translations at the upper and lower surfaces of the laminate in each of the three coordinate directions, and the derivatives of these translations with respect to each coordinate. This choice of degrees of freedom leads to displacement and strain compatibility at the corners. Stacking sequence effects are accounted for by explicitly integrating the strain energy density through the thickness of the element. The laminated solid element was combined with a gap-contact element to analyze thick laminated composite lugs loaded through flexible pins. The resulting model accounts for pin bending effects that produce non-uniform bearing stresses through the thickness of the lug. A thick composite lug experimental test program was performed, and provided data that was used to validate the analytical model. Two lug geometries and three stacking sequences were tested

    Repeated Recovery of Staphylococcus saprophyticus From the Urogenital Tracts of Women: Persistence Vs. Recurrence

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    Objective: The purpose of this study was to determine whether colonization was persistent or recurrent in a small group of women who had repeated recovery of Staphylococcus saprophyticus from their urogenital tracts

    Improved Permafrost Protection using Air Convection and Ventilated Shoulder Cooling Systems - Final Project Report

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    This report focuses on the effectiveness of air convection embankments (ACE) and ventilated shoulder (VS) cooling systems designed to cool foundation soils and preserve permafrost beneath roadway embankments. The three main sections of the report include a literature review, an analysis of field data from Thompson Drive and the Alaska Highway Dot Lake test site, and a discussion of techniques for modeling ACE and VS structures

    Saccharification of Starchy Grain Mashes for Ethonal Fermentation Use of Mold-Amylase Preparations

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    Ethyl alcohol has been listed by scientists as one of the six most useful substances; in fact it has been said that, next to water, ethanol is the most useful chemical compound known to mankind. At the present time approximately 85% of all industrial alcohol is made by fermentation, the balance by synthesis from ethylene derived from the cracking of petroleum. Of the fermentation alcohol about nine-tenths is produced from blackstrap molasses, one-tenth from grains. However, by-product molasses is limited in amount and there is at the present time virtually no surplus. This is shown by the statistics of molasses production (4) and by the fact that the price of molasses has recently risen from 5¢ to 7¢ per gallon. It is likely to rise still higher as alcohol production expands to meet the needs of defense industries. Hence, other raw materials will become increasingly important. Of these, corn is the only one now available in adequate quantities in the United States. The present price of molasses at 7¢ per gallon is equivalent to about 60¢ per bushel for corn as an alcohol source

    Nitrate reductase activity in the subsurface waters of the Peru Current

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    In March 1976 and 1977, nitrate reductase, nitrate, nitrite, and oxygen were measured between depths of 30 and 250m in the subsurface waters overlying the Peruvian continental shelf and shelf edge at 15S latitude. Oxygen concentrations of less than 1 ml/1 began between 20 and 30m in both years. The oxygen deficient waters extended to the bottom on the shelf and to 440m at the shelf edge...
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