1,175 research outputs found

    Plastic strain arrangement in copper single crystals in sliding

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    Deformation of tribologically loaded contact zone is one of the wear mechanisms in spite of the fact that no mass loss may occur during this process. Generation of optimal crystallographic orientations of the grains in a polycrystalline materials (texturing) may cause hardening and reducing the deformation wear. To reveal the orientation dependence of an individual gain and simplify the task we use copper single crystals with the orientations of the compression axis along [11 1] and [110]. The plastic deformation was investigated by means of optical, scanning electron microscopy and EBSD techniques. It was established that at least four different zones were generated in the course of sliding test, such as non-deformed base metal, plastic deformation layer sliding, crystalline lattice reorientation layer and subsurface grain structure layer. The maximum plastic strain penetration depth was observed on [110]-single crystals. The minimum stability of [11 1]-crystals with respect to rotation deformation mode as well as activation of shear in the sliding contact plane provide for rotation deformation localization below the worn surface. The high-rate accumulation of misorientations and less strain penetration depth was observed on [11 1]-crystals as compared to those of [110]-oriented ones

    FAST CARS: Engineering a Laser Spectroscopic Technique for Rapid Identification of Bacterial Spores

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    Airborne contaminants, e.g., bacterial spores, are usually analyzed by time consuming microscopic, chemical and biological assays. Current research into real time laser spectroscopic detectors of such contaminants is based on e.g. resonant Raman spectroscopy. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. The connection with previous studies based on "Coherent Anti-Stokes Raman Spectroscopy" (CARS) is to be noted. However generating and utilizing maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is much more challenging. This extension of the CARS technique is called FAST CARS (Femtosecond Adaptive Spectroscopic Techniques for Coherent Anti-Stokes Raman Spectroscopy), and the present paper proposes and analyses ways in which it could be used to rapidly identify pre-selected molecules in real time.Comment: 43 pages, 21 figures; replacement with references added. Submitted to the Proceedings of National Academy of Science

    Neutron Drops and Skyrme Energy-Density Functionals

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    The Jπ^{\pi}=0+^+ ground state of a drop of 8 neutrons and the lowest 1/2^- and 3/2^- states of 7-neutron drops, all in an external well, are computed accurately with variational and Green's function Monte Carlo methods for a Hamiltonian containing the Argonne v18v_{18} two-nucleon and Urbana IX three-nucleon potentials. These states are also calculated using Skyrme-type energy-density functionals. Commonly used functionals overestimate the central density of these drops and the spin-orbit splitting of 7-neutron drops. Improvements in the functionals are suggested

    Gender disparity in health-related quality of life and fatigue after living renal donation

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    Background: The clinical outcome and health-related quality of life (HRQoL) of living kidney donors is mostly not detrimental, but some donors experience impairment after donation. Gender-specific effects of living kidney donors was evaluated. Methods: Clinical outcome was assessed in living kidney donors and HRQoL was obtained by self-reporting validated test systems as the Multidimensional Fatigue Inventory (MFI-20), the Short Form 36 (SF-36), and the Patient Health Questionnaire (PHQ-9). Results: Two hundred and eleven (211) living renal donors were evaluated (female 62.2%). Response rate was 80.8%. In both genders, a decrease of renal function of 26% was observed after donation. De novo antihypertensives were introduced in 28.3% of women and 36.5% of men. HRQoL was comparable in female and male donors, except for mental HRQoL, which was lower in 51- to 60-year-old female donors, compared to age-matched male donors and to the female general population. Female donors aged 40–59 years demonstrated more fatigue than the age-matched general population. A low mental HRQoL (MCS; SF-36) was associated with higher values for fatigue (General Fatigue Score; MFI-20) in both genders. Multiple regression analysis detected the General Fatigue score of the MFI-20 questionnaire and depression identified by the PHQ-9 score as independent variables predicting MCS of the SF-36 in both genders. Lower age at time of donation contributed to a lower MCS in female donors. Conclusions: Overall, HRQoL in living kidney donors exceeds that of the general population. Inferior mental health status and fatigue seem to be a problem, especially in middle-aged female donors, but not in all female donors. Psychological evaluation pre donation and psychological support post donation are required

    Many-body effects in 16O(e,e'p)

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    Effects of nucleon-nucleon correlations on exclusive (e,ep)(e,e'p) reactions on closed-shell nuclei leading to single-hole states are studied using 16O(e,ep)15N^{16}O(e,e'p)^{15}N (6.326.32 MeV, 3/23/2^-) as an example. The quasi-hole wave function, calculated from the overlap of translationally invariant many-body variational wave functions containing realistic spatial, spin and isospin correlations, seems to describe the initial state of the struck proton accurately inside the nucleus, however it is too large at the surface. The effect of short-range correlations on the final state is found to be largely cancelled by the increase in the transparency for the struck proton. It is estimated that the values of the spectroscopic factors obtained with the DWIA may increase by a few percent due to correlation effects in the final state.Comment: 21 Pages, PHY-7849-TH-9

    Sorghum insect identification handbook

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    This handbook has been published to help agricultural scientists and students to identify the common insect and mite pests of the sorghum crop at all stages of growth, and in storage. To create awareness about the benefit of natural enemies there is a section on the more well known predators and parasites of sorghum pests. General descriptions of the pests and color illustrations are provided to facilitate identification. There are brief descriptions of the biology, nature, and symptoms of damage together with suggested control measures. Chemical control should be applied only if really necessary, and a plant protection specialist should be consulted beforehand, if possible. It is always preferable to confirm the identity of pests with the help of professional entomologists and to collect specimens for future identification when the opportunity arises
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