5,724 research outputs found

    Monitoring Lateral Deflections of a Berthing Structure During Dredging — A Case Study

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    For one of the major ports in India, a shallow water berth is recently constructed comprising of a diaphragm wall and pile rows to support the deck structure. The soil strata are essentially very soft clay extending to a large depth. Reclaiming land behind this structure created number of problems including mud flow. The structure was constructed after placement of fill required for reclamation. After completion of the structure, when dredging work was undertaken, it was decided to monitor the lateral movements of berths, as the dredging depth increases. For this purpose inclinometer tubes were installed in one of the diaphragm wall panels and another in one of the piles of the structure. The structure is analysed using PLAXIS finite element software and results are compare with field measurements which are in good agreements

    Embedded AGN and star formation in the central 80 pc of IC 3639

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    [Abridged] Methods: We use interferometric observations in the NN-band with VLTI/MIDI to resolve the mid-IR nucleus of IC 3639. The origin of the nuclear infrared emission is determined from: 1) the comparison of the correlated fluxes from VLTI/MIDI with the fluxes measured at subarcsec resolution (VLT/VISIR, VLT/ISAAC); 2) diagnostics based on IR fine-structure line ratios, the IR continuum emission, IR bands produced by polycyclic aromatic hydrocarbons (PAH) and silicates; and 3) the high-angular resolution spectral energy distribution. Results: The unresolved flux of IC 3639 is 90±20mJy90 \pm 20\, \rm{mJy} at 10.5μm10.5\, \rm{\mu m}, measured with three different baselines in VLTI (UT1-UT2, UT3-UT4, and UT2-UT3; 4646-58m58\, \rm{m}), making this the faintest measurement so far achieved with mid-IR interferometry. The correlated flux is a factor of 33-44 times fainter than the VLT/VISIR total flux measurement. The observations suggest that most of the mid-IR emission has its origin on spatial scales between 1010 and 80pc80\, \rm{pc} (4040-340mas340\, \rm{mas}). A composite scenario where the star formation component dominates over the AGN is favoured by the diagnostics based on ratios of IR fine-structure emission lines, the shape of the IR continuum, and the PAH and silicate bands. Conclusions: A composite AGN-starburst scenario is able to explain both the mid-IR brightness distribution and the IR spectral properties observed in the nucleus of IC 3639. The nuclear starburst would dominate the mid-IR emission and the ionisation of low-excitation lines (e.g. [NeII]12.8μm_{12.8 \rm{\mu m}}) with a net contribution of 70%\sim 70\%. The AGN accounts for the remaining 30%\sim 30\% of the mid-IR flux, ascribed to the unresolved component in the MIDI observations, and the ionisation of high-excitation lines (e.g. [NeV]14.3μm_{14.3 \rm{\mu m}} and [OIV]25.9μm_{25.9 \rm{\mu m}}).Comment: Accepted for publication in A&

    What measurements of neutrino neutral current events can reveal

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    FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPWe show that neutral current (NC) measurements at neutrino detectors can play a valuable role in the search for new physics. Such measurements have certain intrinsic features and advantages that can fruitfully be combined with the usual well-studied charged lepton detection channels in order to probe the presence of new interactions or new light states. In addition to the fact that NC events are immune to uncertainties in standard model neutrino mixing and mass parameters, they can have small matter effects and superior rates since all three flavours participate. We also show, as a general feature, that NC measurements provide access to different combinations of CP phases and mixing parameters compared to CC measurements at both long and short baseline experiments. Using the Deep Underground Neutrino Experiment (DUNE) as an illustrative setting, we demonstrate the capability of NC measurements to break degeneracies arising in CC measurements, allowing us, in principle, to distinguish between new physics that violates three flavour unitarity and that which does not. Finally, we show that NC measurements can enable us to restrict new physics parameters that are not easily constrained by CC measurements.11124FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2014/19164-62017/02361-1We are grateful to Michel Sorel for providing us with the migration matrices used in this work, for a calculation probing a feature of the results obtained with these matrices, and for very helpful discussions. RG and BK thank Georgia Karagiorgi and Stephen Parke for very useful conversations, and Mark Ross-Lonergan for some very helpful checks of calculations of Long Baseline oscillation probabilities in 3+1. RG acknowledges support in the form of a Neutrino Physics Center Fellowship from the Neutrino Division and Theory Group at Fermilab. He, SP and SR also acknowledge support from the XII Plan Neutrino Project of the Department of Atomic Energy and the High Performance Cluster Facility at HRI. SP thanks Sao Paulo Research Foundation (FAPESP) for the support through Funding Grants No. 2014/19164-6 and No. 2017/02361-1. He also thanks RG for the academic visit at Harish-Chandra Research Institute during 2016-2017. This research was supported in part by the National Science Foundation under Grant No. NSF PHY11-25915. This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes

    Expanding hot flow in the black hole binary SWIFT J1753.5-0127: evidence from optical timing

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    We describe the evolution of optical and X-ray temporal characteristics during the outburst decline of the black hole X-ray binary SWIFT J1753.5-0127. The optical/X-ray cross-correlation function demonstrates a single positive correlation at the outburst peak, then it has multiple dips and peaks during the decline stage, which are then replaced by the precognition dip plus peak structure in the outburst tail. Power spectral densities and phase lags show a complex evolution, revealing the presence of intrinsically connected optical and X-ray quasi-periodic oscillations. For the first time, we quantitatively explain the evolution of these timing properties during the entire outburst within one model, the essence of which is the expansion of the hot accretion flow towards the tail of the outburst. The pivoting of the spectrum produced by synchrotron Comptonization in the hot flow is responsible for the appearance of the anti-correlation with the X-rays and for the optical quasi-periodic oscillations. Our model reproduces well the cross-correlation and phase lag spectrum during the decline stage, which could not be understood with any model proposed before.Comment: 13 pages, 11 figures, MNRAS submitte

    Role of Cyclonic Eddy in enhancing Primary and New production in the Bay of Bengal

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    Highlights: • First direct measurements of new production in an eddy in the Bay of Bengal. • 100% increase in nutrient concentrations is seen due to the eddy. • Eddy enhanced new and primary production in the otherwise less productive Bay of Bengal. Abstract: Eddies can be important in sustaining primary production in the tropical oceans, but their role for nutrient cycling is poorly understood in the under-sampled northern Indian Ocean. To assess the role of cyclonic eddies in enhancing primary production, measurements of primary production were carried out at four stations in the northern Bay of Bengal during the early winter 2007, around a cyclonic eddy close to 17.8 °N, 87.5 °E. Shallowing of the thermocline and halocline by 10 m was observed within the eddy compared to the surroundings; mixed layer depth was also reduced within the eddy. The highest surface productivity (2.71 μM C d− 1) and chlorophyll a (0.18 μg L− 1) were found within the eddy, while the lowest, at its outer edge. Further, the eddy supplied nutrients to the surface layers, shallowing the subsurface chlorophyll maximum as well. Integrated production in the euphotic top layers was more than twice within eddy compared to its outer edge, confirming the role of cyclonic eddies in enhancing the primary production in the otherwise less productive Bay of Bengal. Given new nitrogen input via vertical mixing, river discharge or aerosol deposition, the additional primary production due to this new nutrient input and its contribution to the total production (f-ratio, fraction of exportable organic matter) increased significantly from 0.4 to 0.7, and thus the Bay of Bengal can potentially transfer a high fraction of its total production to the deep, assisted by eddies. We suggest possible improvements in experiments for future studies, and the potential for assessing the role of eddies in biogeochemistry

    Enhanced signal of astrophysical tau neutrinos propagating through Earth

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    Earth absorbs \nue and \numu of energies above about 100 TeV. As is well-known, although \nutau will also disappear through charged-current interactions, the \nutau flux will be regenerated by prompt tau decays. We show that this process also produces relatively large fluxes of secondary \nube and \nubmu, greatly enhancing the detectability of the initial \nutau. This is particularly important because at these energies \nutau is a significant fraction of the expected astrophysical neutrino flux, and only a tiny portion of the atmospheric neutrino flux.Comment: Four pages, two inline figure

    Measurement of marine productivity using 15N and 13C tracers: Some methodological aspects

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    Various experiments involving the measurement of new, regenerated and total productivity using 15N and 13C tracers were carried out in the Bay of Bengal (BOB) and in the Arabian Sea. Results from 15N tracer experiments indicate that nitrate uptake can be underestimated by experiments with incubation time <4 hours. Indirect evidence suggests pico- and nano-phytoplankton, on their dominance over microphytoplankton, can also influence the f-ratios. Difference in energy requirement for assimilation of different nitrogen compounds decides the preferred nitrogen source during the early hours of incubation. Variation in light intensity during incubation also plays a significant role in the assimilation of nitrogen. Results from time course experiments with both 15N and 13C tracers suggest that photoinhibition appears significant in BOB and the Arabian Sea during noon. A significant correlation has been found in the productivity values obtained using 15N and 13C tracers

    Evaluation of Rock Characteristics for a Power Plant Site in India

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    Extensive geotechnical and geophysical investigations were carried out for a power plant site situated on the east coast of southern India. It is proposed to construct the foundation on rock at a depth of 18.0 m below the ground level. The geological and geotechnical characterization of the rock have been presented in this paper. Extensive boreholes were drilled up to 40.0 m to 60.0 m depth and a few boreholes up to 120.0 m depth from the ground level. Seismic crosshole tests were conducted at soil/rock strata upto 65.0 m depth for the determination of S-wave and P-wave velocity at different depths. Dilatometer tests were conducted in weathered and hard rock at 5.0 m interval up to a depth of 65.0 m. Field permeability tests were carried out in deep boreholes by single packer method. Various laboratory tests including UCC, Brazilian, and Point load tests were carried out on rock core samples. Modules obtained from UCC tests are compared with the in-situ modulus obtained from Dilatometer tests. Bearing capacity and settlement analysis are carried out for the proposed raft of about 113 m x 105 m size to be supported on rock. The allowing bearing pressure is estimated based on Rock Mass Rating, RQD and strength of rock cores. The settlement analysis is carried out using modulus obtained from Dilatometer tests and from the laboratory unconfined compression tests on rock core samples. The modulus of subgrade reaction and spring constants in vertical, horizontal and rocking modes of vibration are also evaluated for the static and seismic analysis of the raft
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