5,739 research outputs found

    Developing IFC for infrastructure: A case study of three highway entities

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    Modern cities pay particular attention to upscale their infrastructure systems in order to improve the every-day life of their citizens and lead the way towards a more sustainable environment. As part of this, they invest extensive funds in large infrastructure projects which are challenging to deliver as they require an e efficient communication among different professions, in order to share information efficiently throughout the lifecycle of the project, thus highlighting the importance of standardization to maintain consistency and integrity during data exchange. Building Information Modelling (BIM) aims to facilitate the above-mentioned requirements by describing the life-cycle of the project and Industry Foundation Classes (IFC) is the Standard for BIM that enables an efficient storage, management, exchange and visualization of information. However, there are two important challenges that need to be addressed: (i) IFC focuses particularly on buildings and provides limited support for infrastructure elements and (ii) the information exchange aims to describe mostly the construction phase; highlighting the lack of classes that refer to the operation and maintenance phase. Within this context, this paper proposes the extension of Industry Foundation Classes (IFC) for Asset Management in Infrastructure. A method is developed based on a case study of three highway entities: (i) retaining wall, (ii) gantry and (iii) bridge and a conceptual extension is presented. The results are further discussed and recommendations regarding future research fields are proposed

    Norm Optimal Iterative Learning Control with Application to Problems in Accelerator based Free Electron Lasers and Rehabilitation Robotics

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    This paper gives an overview of the theoretical basis of the norm optimal approach to iterative learning control followed by results that describe more recent work which has experimentally benchmarking the performance that can be achieved. The remainder of then paper then describes its actual application to a physical process and a very novel application in stroke rehabilitation

    Secondary gamma-ray production in a coded aperture mask

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    The application of the coded aperture mask to high energy gamma-ray astronomy will provide the capability of locating a cosmic gamma-ray point source with a precision of a few arc-minutes above 20 MeV. Recent tests using a mask in conjunction with drift chamber detectors have shown that the expected point spread function is achieved over an acceptance cone of 25 deg. A telescope employing this technique differs from a conventional telescope only in that the presence of the mask modifies the radiation field in the vicinity of the detection plane. In addition to reducing the primary photon flux incident on the detector by absorption in the mask elements, the mask will also be a secondary radiator of gamma-rays. The various background components in a CAMTRAC (Coded Aperture Mask Track Chamber) telescope are considered. Monte-Carlo calculations are compared with recent measurements obtained using a prototype instrument in a tagged photon beam line

    Ground‐based measurements of NOx and total reactive oxidized nitrogen (NOy) at Sable Island, Nova Scotia, during the NARE 1993 summer intensive

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    Measurements of NO, NO2, and total reactive oxidized nitrogen (NOy) were added to ongoing measurements of aerosols, CO, and O3 at Sable Island (43°55â€ČN, 60°01â€ČW), Nova Scotia, during the North Atlantic Regional Experiment (NARE) 1993 summer intensive. Ambient levels of NOx and NOy were found to be highly variable, and elevated levels can be attributed to the transport of polluted continental air or presumably to relatively fresh emissions from sources upwind (e.g., ship traffic). The median values for NOx and NOy are 98 and 266 parts per trillion by volume (pptv), respectively. A multiday pollution episode occurred during which elevated NOx and NOy were observed with enhanced levels of O3, CO, and condensation nuclei. Air masses of recent tropical marine origin characterized by low and constant levels of O3 and CO were sampled after Hurricane Emily. The correlation between ozone and CO is reasonably good, although the relation is driven by the single pollution episode observed during the study. The correlation of O3 with NOy and with NOy‐NOx is complicated by the presumed NOy removal processes in the marine boundary layer. Examination of the radiosonde data and comparisons of the surface data with those obtained on the overflying aircraft provide clear indications of vertical stratification above the site

    The impact of new neutrino DIS and Drell-Yan data on large-x parton distributions

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    New data sets have recently become available for neutrino and antineutrino deep inelastic scattering on nuclear targets and for inclusive dimuon production in pp pd interactions. These data sets are sensitive to different combinations of parton distribution functions in the large-x region and, therefore, provide different constraints when incorporated into global parton distribution function fits. We compare and contrast the effects of these new data on parton distribution fits, with special emphasis on the effects at large x. The effects of the use of nuclear targets in the neutrino and antineutrino data sets are also investigated.Comment: 24 pages, 13 figure

    Lambda Polarization in Polarized Proton-Proton Collisions at RHIC

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    We discuss Lambda polarization in semi-inclusive proton-proton collisions, with one of the protons longitudinally polarized. The hyperfine interaction responsible for the Δ\Delta-NN and Σ\Sigma-Λ\Lambda mass splittings gives rise to flavor asymmetric fragmentation functions and to sizable polarized non-strange fragmentation functions. We predict large positive Lambda polarization in polarized proton-proton collisions at large rapidities of the produced Lambda, while other models, based on SU(3) flavor symmetric fragmentation functions, predict zero or negative Lambda polarization. The effect of Σ0\Sigma^0 and Σ∗\Sigma^* decays is also discussed. Forthcoming experiments at RHIC will be able to differentiate between these predictions.Comment: 18 pages, 5 figure

    Temperature-dependent proximity magnetism in Pt

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    We experimentally demonstrate the existence of magnetic coupling between two ferromagnets separated by a thin Pt layer. The coupling remains ferromagnetic regardless of the Pt thickness, and exhibits a significant dependence on temperature. Therefore, it cannot be explained by the established mechanisms of magnetic coupling across nonmagnetic spacers. We show that the experimental results are consistent with the presence of magnetism induced in Pt in proximity to ferromagnets, in direct analogy to the well-known proximity effects in superconductivity.Comment: 4 pages, 3 figure

    Mapping the autistic advantage from the accounts of adults diagnosed with autism: A qualitative study

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    This is the final version. Available on open access from Mary Ann Liebert via the DOI in this recordBackground: Autism has been associated with specific cognitive strengths. Strengths and weaknesses have traditionally been conceptualized as dichotomous. Methods: We conducted 28 semi-structured interviews with autistic adults. Maximum variation sampling was used to ensure diversity in relation to support needs. We asked which personal traits adults attributed to their autism, and how these have helped in the workplace, in relationships, and beyond. Data were collected in two stages. Responses were analyzed using content and thematic techniques. Results: The ability to hyperfocus, attention to detail, good memory, and creativity were the most frequently described traits. Participants also described specific qualities relating to social interaction, such as honesty, loyalty, and empathy for animals or for other autistic people. In thematic analysis we found that traits associated with autism could be experienced either as advantageous or disadvantageous dependent on moderating influences. Moderating influences included the social context in which behaviors occurred, the ability to control behaviors, and the extent to which traits were expressed. Conclusions: Separating autistic strengths from weaknesses may be a false dichotomy if traits cannot be isolated as separate constructs of strengths or deficits. If attempts to isolate problematic traits from advantageous traits are ill conceived, there may be implications for interventions that have reduction in autistic traits as a primary outcome measure.Wellcome Trus

    Metallic behaviour of carrier-polarized C60_{60} molecular layers: Experiment and Theory

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    Although C60_{60} is a molecular crystal with a bandgap Eg_g of ~2.5 eV, we show that Eg_g is strongly affected by injected charge. In sharp contrast to the Coulomb blockade typical of quantum dots, Eg_g is {\it reduced} by the Coulomb effects. The conductance of a thin C60_{60} layer sandwiched between metal (Al, Ag, Au, Mg and Pt) contacts is investigated. Excellent Ohmic conductance is observed for Al electrodes protected with ultra-thin LiF layers. First-principles calculations, Hubbard models etc., show that the energy gap of C60_{60} is dramatically reduced when electrons hop from C60−_{60}^- to C60_{60}.Comment: 4 PRL style pages, 2 figures. email: [email protected]

    Operating characteristics of a prototype high energy gamma-ray telescope

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    The field of gamma-ray astronomy in the energy range from ten to several hundred MeV is severely limited by the angular resolution that can be achieved by present instruments. The identification of some of the point sources found by the COS-B mission and the resolution of detailed structure existing in those sources may depend on the development of a new class of instrument. The coded aperture mask telescope, used successfully at X-ray energies hold the promise of being such an instrument. A prototype coded aperture telescope was operated in a tagged photon beam ranging in energy from 23 to 123 MeV. The purpose of the experiment was to demonstrate the feasibility of operating a coded aperture mask telescope in this energy region. Some preliminary results and conclusions drawn from some of the data resulting from this experiment are presented
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