1,846 research outputs found

    Changes In The Bacterial Flora Of Sewage During Storage

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    Surface Flaw Detection with Ferromagnetic Resonance Probes

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    Small ferromagnetic resonators have been shown to provide effective electromagnetic detectors for surface flaws in magnetic and nonmagnetic metals. As such a resonator is moved along \u27the surface of a test piece it experiences a frequency shift when it passes over a flaw. lwo detection mechanisms are present: (1) an eddy current effect (2) a perturbation of the dc magnetic bias field used to tune the resonator. Results are given for experiments performed on machined slots in aluminum, titanium and steel and on tightly closed fatigue cracks in titanium. Results are also presented for some measurements on titanium aircraft fasteners

    Scheduling language and algorithm development study. Volume 3, phase 2: As-built specifications for the prototype language and module library

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    Detailed specifications of the prototype language and module library are presented. The user guide to the translator writing system is included

    Measurement of Surface Crack Opening Displacements Using Microwave Frequency Eddy Currents

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    An electromagnetic NDE technique for measuring the crack opening displacement of surface fatigue cracks is described. A ferromagnetic resonance probe utilizing yttrium-iron-garnet was used to induce eddy currents in an aluminum plate. The crack opening disolacement of a semi-elliptical fatigue crack evaluated at the surface was measured optically at several values of bending stress on the specimen. A technique is presented which allows the crack depth to be calculated from the measured COD at a given stress. The relative phase and magnitude of input vs. output signal to and from the resonating YIG sphere was recorded during the interaction of the FMR probe eddy currents and the fatigue crack. A method is shown to extract quantitative information from these signals and to correlate this information with the crack opening displacement

    Girls’ and women’s education within Unesco and the World Bank, 1945–2000

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    By 2000, girls’ and women’s education was a priority for international development organisations. While studies have examined the impact of recent campaigns and programmes, there has been less exploration of ideas about girls’ and women’s education within development thought in the immediate post?colonial period, and the political mechanisms through which this came to be a global concern. Through a study of policy documents, this paper investigates how the education of girls and women came to be prioritised within the two principle UN agencies involved with education since 1945, the World Bank and Unesco. A shift in priorities is evident, from ensuring formal rights and improving the status of women, to expanding the productive capacities of women, fertility control and poverty reduction. While the ascendance of human capital theory provided a space for a new perception of the role of women’s education in development, in other policy arenas women’s education was central to exploring more substantive, rights?based notions of gender equality. Ultimately, the goal of improving girls’ and women’s education fitted into diverse development agendas, paving the way for it to become a global development priority

    Comprehensive survey of energetic electron events in Mercury\u27s magnetosphere with data from the MESSENGER Gamma-Ray and Neutron Spectrometer

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    Data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Gamma-Ray and Neutron Spectrometer have been used to detect and characterize energetic electron (EE) events in Mercury\u27s magnetosphere. This instrument detects EE events indirectly via bremsstrahlung photons that are emitted when instrument and spacecraft materials stop electrons having energies of tens to hundreds of keV. From Neutron Spectrometer data taken between 18 March 2011 and 31 December 2013 we have identified 2711 EE events. EE event amplitudes versus energy are distributed as a power law and have a dynamic range of a factor of 400. The duration of the EE events ranges from tens of seconds to nearly 20 min. EE events may be classified as bursty (large variation with time over an event) or smooth (small variation). Almost all EE events are detected inside Mercury\u27s magnetosphere on closed field lines. The precise occurrence times of EE events are stochastic, but the events are located in well-defined regions with clear boundaries that persist in time and form what we call “quasi-permanent structures.” Bursty events occur closer to dawn and at higher latitudes than smooth events, which are seen near noon-to-dusk local times at lower latitudes. A subset of EE events shows strong periodicities that range from hundreds of seconds to tens of milliseconds. The few-minute periodicities are consistent with the Dungey cycle timescale for the magnetosphere and the occurrence of substorm events in Mercury\u27s magnetotail region. Shorter periods may be related to phenomena such as north-south bounce processes for the energetic electrons

    Solar fusion cross sections II: the pp chain and CNO cycles

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    We summarize and critically evaluate the available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars and to solar neutrino production. Recommended values and uncertainties are provided for key cross sections, and a recommended spectrum is given for 8B solar neutrinos. We also discuss opportunities for further increasing the precision of key rates, including new facilities, new experimental techniques, and improvements in theory. This review, which summarizes the conclusions of a workshop held at the Institute for Nuclear Theory, Seattle, in January 2009, is intended as a 10-year update and supplement to Reviews of Modern Physics 70 (1998) 1265.Comment: 54 pages, 20 figures, version to be published in Reviews of Modern Physics; various typos corrected and several updates mad
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