933 research outputs found

    Progressive damage in stitched composites: Static tensile tests and tension-tension fatigue

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    The paper describes progressive damage in static tensile tests and tension-tension fatigue in structurally stitched carbon/epoxy NCF composites, in comparison with their non-stitched counterparts. Analogies between damage development in quasi-static tension and tension-tension fatigue are analyzed and links between the damage initiation thresholds in quasi-static tests and fatigue life are established

    Transition energy and lifetime for the ground state hyperfine splitting of high Z lithiumlike ions

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    The ground state hyperfine splitting values and the transition probabilities between the hyperfine structure components of high Z lithiumlike ions are calculated in the range Z=4983Z=49-83. The relativistic, nuclear, QED and interelectronic interaction corrections are taken into account. It is found that the Bohr-Weisskopf effect can be eliminated in a combination of the hyperfine splitting values of the hydrogenlike and lithiumlike ions of an isotope. This gives a possibility for testing the QED effects in a combination of the strong electric and magnetic fields of the heavy nucleus. Using the experimental result for the 1s1s hyperfine splitting in ^{209}Bi^{82+}, the 2s hyperfine splitting in ^{209}Bi^{80+} is calculated to be \Delta E=0.7969(2) eV.Comment: The nuclear charge distribution correction \delta is corrected, 14 pages, Late

    Surface-sensitive NMR in optically pumped semiconductors

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    We present a scheme of surface-sensitive nuclear magnetic resonance in optically pumped semiconductors, where an NMR signal from a part of the surface of a bulk compound semiconductor is detected apart from the bulk signal. It utilizes optically oriented nuclei with a long spin-lattice relaxation time as a polarization reservoir for the second (target) nuclei to be detected. It provides a basis for the nuclear spin polarizer [IEEE Trans. Appl. Supercond. 14, 1635 (2004)], which is a polarization reservoir at a surface of the optically pumped semiconductor that polarizes nuclear spins in a target material in contact through the nanostructured interfaces.Comment: 4 pages, 5 figure

    Simulacral, genealogical, auratic and representational failure: Bushman authenticity as methodological collapse

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    This article engages with the concept of authenticity as deployed in anthropology. The first section critiques authenticity as a simple reference to cultural purity, a traditional isomorphism or historical verisimilitude or as an ‘ethnographic authenticity’. Demarcation of authenticity must take into account philosophical literature that argues that authenticity is an existential question of the ‘modern’ era. Thus, authenticity is offered to us as individuals as a remedy for the maladies of modernity: alienation, anomie and alterity. Authenticity is then discussed as a question of value within an economy of cultural politics that often draws on simulacra, creating cultural relics of dubious origin. The final section discusses various methodological failures and problematiques that are highlighted by the concern for, and scrutiny of, authenticity. The first is the simulacral failure. The subjects of anthropology are mostly real flesh-and-blood people-on-the-ground with real needs. In contrast is the simulacral subject, the brand, the tourist image, the media image or the ever-familiar hyper-real bushmen. Lastly, the article considers what Spivak calls ‘withholding’ – a resistance to authentic representation by the Other. Resistance suggests a need for a radically altered engagement with the Other that includes both a deepening, and an awareness, of anthropology as a process of common ontological unfolding

    Intercultural sensitivity in the integrating suburb of Westville. Durban, South Africa.

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    To investigate intercultural sensitivity, the Davis Russell-Peters Intercultural Sensitivity Instrument (1994) was administered to 203 participants situated within residences in the formerly white suburb of Westville Durban, South Africa. The subjective experience of the participants was evaluated by comparing demographic variables with a suggested continuum of six stages between ethnocentrism and ethnorelativism. Respondents appeared to traverse the polarities related to their perceptions of reality and its subjective meaning. The preference for ethnocentric attitudes appeared to be a construct employed as a result of categorization and separation caused by former restrictive legislation of Apartheid. and strong cultural and religious anchors. It appears that groups gravitate towards their own cultural group because of the security it offers in times of political unrest and fear. Also, groups appeared to maintain healthy self-concepts and a preference for ethnorelativism, creating a world that values difference and is open to integration with the larger society
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