6,470 research outputs found

    Geological investigation of palaeotsunamis in the Samoan islands: interim report and research directions

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    The Komandorsky seismic gap has distinctive boundaries and a length of 650 km. Its period of “seismic silence” comes close to the maximum recurrence interval for great earthquakes in the Aleutian Island Arc - the stress concentration here probably having reached the critical value. So,estimation of possible earthquake and tsunami characteristics within this gap becomes a significant problem. The closest analog of a similar gap is the area where the 2004 Sumatra-Andaman catastrophic event occurred. Thus, for the present study we used the same modeling scheme as we used for that event. It was assumed that a source length of 650 km, consisting of 9 blocks, and an earthquake with a moment magnitude MW=8.5. Several block motion scenarios were considered. The tsunami generation and propagation in the Pacific Ocean and the possible wave characteristics on near and far-field coasts were estimated. Modeling of such an event showed that the wave heights on different Pacific coasts will vary from 3 to 9 meters. A tsunami wave with a 9-meter height is capable in causing significant loss of human life and economic damage.© 2013, Tsunami Society International

    Diffusive counter dispersion of mass in bubbly media

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    We consider a liquid bearing gas bubbles in a porous medium. When gas bubbles are immovably trapped in a porous matrix by surface-tension forces, the dominant mechanism of transfer of gas mass becomes the diffusion of gas molecules through the liquid. Essentially, the gas solution is in local thermodynamic equilibrium with vapor phase all over the system, i.e., the solute concentration equals the solubility. When temperature and/or pressure gradients are applied, diffusion fluxes appear and these fluxes are faithfully determined by the temperature and pressure fields, not by the local solute concentration, which is enslaved by the former. We derive the equations governing such systems, accounting for thermodiffusion and gravitational segregation effects which are shown not to be neglected for geological systems---marine sediments, terrestrial aquifers, etc. The results are applied for the treatment of non-high-pressure systems and real geological systems bearing methane or carbon dioxide, where we find a potential possibility of the formation of gaseous horizons deep below a porous medium surface. The reported effects are of particular importance for natural methane hydrate deposits and the problem of burial of industrial production of carbon dioxide in deep aquifers.Comment: 10 pages, 5 figures, 1 table, Physical Review

    Magnetic Excitations in the Quasi-1D Ising-like Antiferromagnet TlCoCl3_3

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    Neutron inelastic scattering measurements have been performed in order to investigate the magnetic excitations in the quasi-1D Ising-like antiferromagnet TlCoCl3_3. We observed the magnetic excitation, which corresponds to the spin-wave excitation continuum corresponding to the domain-wall pair excitation in the 1D Ising-like antiferromagnet. According to the Ishimura-Shiba theory, we analyzed the observed spin-wave excitation, and the exchange constant 2J2J and the anistropy ϵ\epsilon were estimated as 14.7 meV and 0.14 in TlCoCl3_3, respectively.Comment: 2 pages, 3 figures, jpsj2.cls, to be published in J. Phys. Soc. Jpn. Vol.75 (2006) No.

    Off-diagonal Interactions, Hund's Rules and Pair-binding in Hubbard Molecules

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    We have studied the effect of including nearest-neighbor, electron-electron interactions, in particular the off-diagonal (non density-density) terms, on the spectra of truncated tetrahedral and icosahedral ``Hubbard molecules,'' focusing on the relevance of these systems to the physics of doped C60_{60}. Our perturbation theoretic and exact diagonalization results agree with previous work in that the density-density term suppresses pair-binding. However, we find that for the parameter values of interest for C60C_{60} the off-diagonal terms {\em enhance} pair-binding, though not enough to offset the suppression due to the density-density term. We also find that the critical interaction strengths for the Hund's rules violating level crossings in C602_{60}^{-2}, C603_{60}^{-3} and C604_{60}^{-4} are quite insensitive to the inclusion of these additional interactions.Comment: 20p + 5figs, Revtex 3.0, UIUC preprint P-94-10-08

    From Design to Production Control Through the Integration of Engineering Data Management and Workflow Management Systems

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    At a time when many companies are under pressure to reduce "times-to-market" the management of product information from the early stages of design through assembly to manufacture and production has become increasingly important. Similarly in the construction of high energy physics devices the collection of (often evolving) engineering data is central to the subsequent physics analysis. Traditionally in industry design engineers have employed Engineering Data Management Systems (also called Product Data Management Systems) to coordinate and control access to documented versions of product designs. However, these systems provide control only at the collaborative design level and are seldom used beyond design. Workflow management systems, on the other hand, are employed in industry to coordinate and support the more complex and repeatable work processes of the production environment. Commercial workflow products cannot support the highly dynamic activities found both in the design stages of product development and in rapidly evolving workflow definitions. The integration of Product Data Management with Workflow Management can provide support for product development from initial CAD/CAM collaborative design through to the support and optimisation of production workflow activities. This paper investigates this integration and proposes a philosophy for the support of product data throughout the full development and production lifecycle and demonstrates its usefulness in the construction of CMS detectors.Comment: 18 pages, 13 figure

    ECORD geophysical and geotechnical hazard site survey offshore Yucatan, Mexico : cruise 2013/4_ECORD

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    This report provides information on the University of Texas, Institute for Geophysics (UTIG) led ECORD (European Consortium for Ocean Research Drilling) geophysical and geotechnical hazard site survey offshore Yucatan aboard the R/V Justo Sierra which took place from the 16th April to the 23rd April 2013 over a study area within the Chixculub impact crater. The cruise has been carried out under contract for ECORD comprising the acquisition of geophysical data (surface tow boomer, side scan sonar, multibeam echosounder, magnetometer and CHIRP data) and geotechnical data (cone penetrometer tests (CPT)), ahead of scheduled ECORD led drilling of the Chixculub impact crater. The survey was undertaken in joint collaboration between UTIG and Universidad Nacional Autonóma de México (UNAM). Seafloor Geotec, LLC, was commissioned to carry out CPTs at selected sites within the survey area

    Polarized Neutron Inelastic Scattering Study of the Anisotropic Magnetic Fluctuations in the Quasi-1D Ising-like Antiferromagnet TlCoCl3_3

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    Polarized neutron inelastic scattering experiments have been carried out in the quasi-1D Ising-like antiferromagnet TlCoCl3_3. We observed the longitudinal magnetic fluctuation Szz(Q,ω)S_{zz} (Q, \omega) for the spin-wave excitation continuum, which has not been observed in the unpolarized neutron inelastic scattering experiments of the quasi-1D Ising-like antiferromagnets CsCoCl3_3 and TlCoCl3_3 so far, together with the transverse magnetic fluctuation Sxx(Q,ω)S_{xx} (Q, \omega). We compared both obtained intensities of Sxx(Q,ω)S_{xx} (Q, \omega) and Szz(Q,ω)S_{zz} (Q, \omega) with the perturbation theory from the pure Ising limit by Ishimura and Shiba, and a semi-quantitative agreement was found.Comment: 5 pages, 5 figures, jpsj2.cls, to be published in J. Phys. Soc. Jpn. Vol. 75 (2006) No.

    Spin Wave Response in the Dilute Quasi-one Dimensional Ising-like Antiferromagnet CsCo_{0.83}Mg_{0.17}Br_3

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    Inelastic neutron scattering profiles of spin waves in the dilute quasi-one-dimensional Ising-like antiferromagnet CsCo_{0.83}Mg_{0.17}Br_3 have been investigated. Calculations of S^{xx}(Q,omega), based on an effective spin Hamiltonian, accurately describe the experimental spin wave spectrum of the 2J mode. The Q dependence of the energy of this spin wave mode follows the analytical prediction omega_{xx}(Q)=(2J)(1-5epsilon^{2}cos^{2}Qa+2epsilon^{2})^{1/2}, calculated by Ishimura and Shiba using perturbation theory.Comment: 13 pages, 4 figure
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