2,766 research outputs found

    Viscous and Viscoelastic Behavior of 1,3,5-tri-alpha-naphthyl Benzene

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    Torsional creep and creep recovery behavior of organic liquid

    Hindcasting of hurricane characteristics and observed storm damage on a fringing reef, Jamaica, West Indies

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    Hurricane Allen is one of the most severe hurricanes on record and caused extensive damage throughout the Caribbean in early August 1980. Coral reefs along the north coast of Jamaica were devastated by the hurricane-induced waves. As in the case of most hurricanes, no wave measurements were made. We have computed the wind field and hindcast the deep water wave characteristics as the storm impacted the fringing reef at Discovery Bay on the north central coast of Jamaica. The deep water waves propagated into shallow water on the forereef and transformed as a result of shoaling and refraction. We found that significant wave height at a given time varied by a factor of 2.6 and that incident wave power for the duration of the storm varied by a factor of 7 along a 3 km section of the Discovery Bay forereef due to variations in local bathymetry. Maximum hindcast breakers reached a height of 11.5 m with a significant wave period of 10.5 s. Observations of the most intense reef damage coincided with areas on the eastern forereef experiencing the highest breakers. We speculate that the degree of reef damage is a function of how much time has elapsed since the previous storm rather than frequency of hurricanes at a locality

    Verifying Heap-Manipulating Programs with Unknown Procedure Calls

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    10.1007/978-3-642-16901-4_13Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)6447 LNCS171-18

    Using Artificial Intelligence to Identify Perpetrators of Technology Facilitated Coercive Control.

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    This study investigated the feasibility of using Artificial Intelligence to identify perpetrators of coercive control through digital data held on mobile phones. The research also sought the views of the police and victim/survivors of domestic abuse to using technology in this way

    SOME ABSTRACT PROPERTIES OF SEMIGROUPS APPEARING IN SUPERCONFORMAL THEORIES

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    A new type of semigroups which appears while dealing with N=1N=1 superconformal symmetry in superstring theories is considered. The ideal series having unusual abstract properties is constructed. Various idealisers are introduced and studied. The ideal quasicharacter is defined. Green's relations are found and their connection with the ideal quasicharacter is established.Comment: 11 page

    Snowmass 2001: Jet Energy Flow Project

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    Conventional cone jet algorithms arose from heuristic considerations of LO hard scattering coupled to independent showering. These algorithms implicitly assume that the final states of individual events can be mapped onto a unique set of jets that are in turn associated with a unique set of underlying hard scattering partons. Thus each final state hadron is assigned to a unique underlying parton. The Jet Energy Flow (JEF) analysis described here does not make such assumptions. The final states of individual events are instead described in terms of flow distributions of hadronic energy. Quantities of physical interest are constructed from the energy flow distribution summed over all events. The resulting analysis is less sensitive to higher order perturbative corrections and the impact of showering and hadronization than the standard cone algorithms.Comment: REVTeX4, 13 pages, 6 figures; Contribution to the P5 Working Group on QCD and Strong Interactions at Snowmass 200

    MICROMEGAS chambers for hadronic calorimetry at a future linear collider

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    Prototypes of MICROMEGAS chambers, using bulk technology and analog readout, with 1x1cm2 readout segmentation have been built and tested. Measurements in Ar/iC4H10 (95/5) and Ar/CO2 (80/20) are reported. The dependency of the prototypes gas gain versus pressure, gas temperature and amplification gap thickness variations has been measured with an 55Fe source and a method for temperature and pressure correction of data is presented. A stack of four chambers has been tested in 200GeV/c and 7GeV/c muon and pion beams respectively. Measurements of response uniformity, detection efficiency and hit multiplicity are reported. A bulk MICROMEGAS prototype with embedded digital readout electronics has been assembled and tested. The chamber layout and first results are presented

    Predicate Abstraction for Linked Data Structures

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    We present Alias Refinement Types (ART), a new approach to the verification of correctness properties of linked data structures. While there are many techniques for checking that a heap-manipulating program adheres to its specification, they often require that the programmer annotate the behavior of each procedure, for example, in the form of loop invariants and pre- and post-conditions. Predicate abstraction would be an attractive abstract domain for performing invariant inference, existing techniques are not able to reason about the heap with enough precision to verify functional properties of data structure manipulating programs. In this paper, we propose a technique that lifts predicate abstraction to the heap by factoring the analysis of data structures into two orthogonal components: (1) Alias Types, which reason about the physical shape of heap structures, and (2) Refinement Types, which use simple predicates from an SMT decidable theory to capture the logical or semantic properties of the structures. We prove ART sound by translating types into separation logic assertions, thus translating typing derivations in ART into separation logic proofs. We evaluate ART by implementing a tool that performs type inference for an imperative language, and empirically show, using a suite of data-structure benchmarks, that ART requires only 21% of the annotations needed by other state-of-the-art verification techniques

    Massive stars exploding in a He-rich circumstellar medium. IV. Transitional Type Ibn Supernovae

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    We present ultraviolet, optical and near-infrared data of the Type Ibn supernovae (SNe) 2010al and 2011hw. SN 2010al reaches an absolute magnitude at peak of M(R) = -18.86 +- 0.21. Its early light curve shows similarities with normal SNe Ib, with a rise to maximum slower than most SNe Ibn. The spectra are dominated by a blue continuum at early stages, with narrow P-Cygni He I lines indicating the presence of a slow-moving, He-rich circumstellar medium. At later epochs the spectra well match those of the prototypical SN Ibn 2006jc, although the broader lines suggest that a significant amount of He was still present in the stellar envelope at the time of the explosion. SN 2011hw is somewhat different. It was discovered after the first maximum, but the light curve shows a double-peak. The absolute magnitude at discovery is similar to that of the second peak (M(R) = -18.59 +- 0.25), and slightly fainter than the average of SNe Ibn. Though the spectra of SN 2011hw are similar to those of SN 2006jc, coronal lines and narrow Balmer lines are cleary detected. This indicates substantial interaction of the SN ejecta with He-rich, but not H-free, circumstellar material. The spectra of SN 2011hw suggest that it is a transitional SN Ibn/IIn event similar to SN 2005la. While for SN 2010al the spectro-photometric evolution favours a H-deprived Wolf-Rayet progenitor (of WN-type), we agree with the conclusion of Smith et al. (2012) that the precursor of SN 2011hw was likely in transition from a luminous blue variable to an early Wolf-Rayet (Ofpe/WN9) stage.Comment: 23 pages, 11 figures, 6 tables. Accepted by MNRA
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