738 research outputs found

    A study of wire breakup and in-flight particle behaviour during wire flame spraying of aluminium

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    Although wire flame spraying has been used for many years, there has been relatively little attention given to understanding the process dynamics. In this work, imaging of the molten wire tip, particle imaging using the Oseir Spray Watch system and particle capture (wipe tests) have all been employed to quantify plume behaviour. Aluminium wire feedstock is melted and then breaks-up close to the exit of the spray nozzle in a non-axisymmetric manor. The mean velocity and diameter of the particles detected by the Spray Watch system change little with stand-off distance with values of approximately 280 m/s and 70 μm respectively for the spray parameters employed. The particle diagnostic system could not detect particles ⪅ 45 μm in diameter and it is estimated that these account for no more than 53 % of the sprayed material. Overall, wire flame spraying generates a surprisingly stable particle stream

    Effect of green manure management on barley yields and N-recovery

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    Mulching of GM herbage can increase cereal yields compared to its removal. However, the same GM herbage removed for biogas production will provide biogas residue that can be used as spring fertilizer to cereals. This will improve N-recovery and reduce the risk for N pollution. Cooperation with existing biogas plants will be more efficient, as building small biogas plants are costly and challenging

    Description of superdeformed nuclei in the interacting boson model

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    The interacting boson model is extended to describe the spectroscopy of superdeformed bands. Microscopic structure of the model in the second minimum is discussed and superdeformed bosons are introduced as the new building blocks. Solutions of a quadrupole Hamiltonian are implemented through the 1/N1/N expansion method. Effects of the quadrupole parameters on dynamic moment of inertia and electric quadrupole transition rates are discussed and the results are used in a description of superdeformed bands in the Hg-Pb and Gd-Dy regions.Comment: 18 pages revtex, 9 figures available upon reques

    Resultant pressure distribution pattern along the basilar membrane in the spiral shaped cochlea

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    Cochlea is an important auditory organ in the inner ear. In most mammals, it is coiled as a spiral. Whether this specific shape influences hearing is still an open problem. By employing a three dimensional fluid model of the cochlea with an idealized geometry, the influence of the spiral geometry of the cochlea is examined. We obtain solutions of the model through a conformal transformation in a long-wave approximation. Our results show that the net pressure acting on the basilar membrane is not uniform along its spanwise direction. Also, it is shown that the location of the maximum of the spanwise pressure difference in the axial direction has a mode dependence. In the simplest pattern, the present result is consistent with the previous theory based on the WKB-like approximation [D. Manoussaki, Phys. Rev. Lett. 96, 088701(2006)]. In this mode, the pressure difference in the spanwise direction is a monotonic function of the distance from the apex and the normal velocity across the channel width is zero. Thus in the lowest order approximation, we can neglect the existance of the Reissner's membrane in the upper channel. However, higher responsive modes show different behavior and, thus, the real maximum is expected to be located not exactly at the apex, but at a position determined by the spiral geometry of the cochlea and the width of the cochlear duct. In these modes, the spanwise normal velocities are not zero. Thus, it indicates that one should take into account of the detailed geometry of the cochlear duct for a more quantitative result. The present result clearly demonstrates that not only the spiral geometry, but also the geometry of the cochlear duct play decisive roles in distributing the wave energy.Comment: 21 pages. (to appear in J. Biol. Phys.

    Progressive transformation of a flux rope to an ICME

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    The solar wind conditions at one astronomical unit (AU) can be strongly disturbed by the interplanetary coronal mass ejections (ICMEs). A subset, called magnetic clouds (MCs), is formed by twisted flux ropes that transport an important amount of magnetic flux and helicity which is released in CMEs. At 1 AU from the Sun, the magnetic structure of MCs is generally modeled neglecting their expansion during the spacecraft crossing. However, in some cases, MCs present a significant expansion. We present here an analysis of the huge and significantly expanding MC observed by the Wind spacecraft during 9 and 10 November, 2004. After determining an approximated orientation for the flux rope using the minimum variance method, we precise the orientation of the cloud axis relating its front and rear magnetic discontinuities using a direct method. This method takes into account the conservation of the azimuthal magnetic flux between the in- and out-bound branches, and is valid for a finite impact parameter (i.e., not necessarily a small distance between the spacecraft trajectory and the cloud axis). Moreover, using the direct method, we find that the ICME is formed by a flux rope (MC) followed by an extended coherent magnetic region. These observations are interpreted considering the existence of a previous larger flux rope, which partially reconnected with its environment in the front. These findings imply that the ejected flux rope is progressively peeled by reconnection and transformed to the observed ICME (with a remnant flux rope in the front part).Comment: Solar Physics (in press

    Monitoring anti-tuberculosis treatment response using analysis of whole blood Mycobacterium tuberculosis specific T cell activation and functional markers

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    Background: Blood-based biomarkers have been proposed as an alternative to current sputum-based treatment monitoring methods in active tuberculosis (ATB). The aim of this study was to validate previously described phenotypic, activation, and cytokine markers of treatment response in a West African cohort. Methods: Whole blood immune responses to Mycobacterium tuberculosis ESAT-6/CFP-10 (EC) and purified protein derivative (PPD) were measured in twenty adults at baseline and after 2 months of standard TB treatment. Patients were classified as fast or slow responders based on a negative or positive sputum culture result at 2 months, respectively. Cellular expression of activation markers (CD38, HLA-DR), memory markers (CD27), and functional intracellular cytokine and proliferation (IFN-γ, Ki-67, TNF-α) markers were measured using multi-color flow cytometry. Results: There was a significant increase in the proportion of CD4+CD27+ cells expressing CD38 and HLA-DR following EC stimulation at 2 months compared to baseline (p = 0.0328 and p = 0.0400, respectively). Following PPD stimulation, slow treatment responders had a significantly higher proportion of CD8+CD27–IFN-γ+ (p = 0.0105) and CD4+CD27+HLA-DR+CD38+ (p = 0.0077) T cells than fast responders at baseline. Receiver operating curve analysis of these subsets resulted in 80% sensitivity and 70 and 100% specificity, respectively (AUC of 0.82, p = 0.0156 and 0.84, p = 0.0102). Conclusion: Our pilot data show reductions in expression of T cell activation markers were seen with treatment, but this was not associated with fast or slow sputum conversion at 2 months. However, baseline proportions of activated T cell subsets are potentially predictive of the subsequent speed of response to treatment

    Microscopic Structure of High-Spin Vibrational Excitations in Superdeformed 190,192,194Hg

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    Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed bands in 190Hg, 192Hg, and 194Hg. The K=2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. At finite frequency, however, the interplay between rotation and vibrations produces different effects depending on neutron number: The lowest octupole phonon is rotationally aligned in 190Hg, is crossed by the aligned two-quasiparticle bands in 192Hg, and retains the K=2 octupole vibrational character up to the highest frequency in 194Hg. The gamma vibrations are predicted to be higher in energy and less collective than the octupole vibrations. From a comparison with the experimental dynamic moments of inertia, a new interpretation of the observed excited bands invoking the K=2 octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in SD Hg nuclei.Comment: 22 pages, REVTeX, 12 postscript figures are available on reques

    Superdeformed rotational bands in the Mercury region; A Cranked Skyrme-Hartree-Fock-Bogoliubov study

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    A study of rotational properties of the ground superdeformed bands in \Hg{0}, \Hg{2}, \Hg{4}, and \Pb{4} is presented. We use the cranked Hartree-Fock-Bogoliubov method with the {\skm} parametrization of the Skyrme force in the particle-hole channel and a seniority interaction in the pairing channel. An approximate particle number projection is performed by means of the Lipkin-Nogami prescription. We analyze the proton and neutron quasiparticle routhians in connection with the present information on about thirty presently observed superdeformed bands in nuclei close neighbours of \Hg{2}.Comment: 26 LaTeX pages, 14 uuencoded postscript figures included, Preprint IPN-TH 93-6
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