1,922 research outputs found

    The Role of Middle Range Publications in the Development of Engineering Knowledge

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    This paper explores the role of publications in the development of engineering knowledge. Previous studies of scientific and technical publications tend to assume that engineers are like scientists in their use of scientific journals as a means of communicating new technical knowledge. But science differs from technology and we should not expect scientists and engineers to use the same sources of knowledge. We contend that previous studies of publications have been flawed because they ignore other forms of publication more suited to the communication of technical and engineering knowledge. This paper argues that technologists use "middle range" publications to exchange knowledge and explore implications of their technological experiences. By providing more visual images, experience-based reports and background information on technologies and products, middle range publications better reflect the ways in which engineers think and work. They allow for visual conversations and support visual communities. The paper provides a detailed exploration of the role of middle range publications and suggests a framework for future research on patterns of publication by technologists and engineers.engineering knowledge, engineering and design organisations, construction, scientific publications, technical publications, innovation studies

    On the efficient numerical solution of lattice systems with low-order couplings

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    We apply the Quasi Monte Carlo (QMC) and recursive numerical integration methods to evaluate the Euclidean, discretized time path-integral for the quantum mechanical anharmonic oscillator and a topological quantum mechanical rotor model. For the anharmonic oscillator both methods outperform standard Markov Chain Monte Carlo methods and show a significantly improved error scaling. For the quantum mechanical rotor we could, however, not find a successful way employing QMC. On the other hand, the recursive numerical integration method works extremely well for this model and shows an at least exponentially fast error scaling

    Design Performance Measurement in the Construction Sector: A Pilot Study

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    This paper examines the role and deployment of design performance measurements (DPMs) in the construction industry, focusing on the consulting engineering sector, the design 'heart' of construction. Compared with manufacturing, there has been very little research on the use of DPMs in construction, and firms often struggle to find appropriate performance indicators. Using results from structured questionnaires, the paper shows that the few DPMs which do exist focus mainly on cost. Other measures are needed to address quality, innovative performance and client satisfaction. In contrast to manufacturing, DPMs in construction also need to address the project-based, multi-firm and non-routine nature of construction design, as well as the separation of design from manufacturing, build and operation. Interviews and workshops with industrialists were used to identify recent DPM practices in construction and combine these with lessons from other sectors. The resulting DPM tools provide guidance on how to: (a) integrate design into wider business processes in construction; (b) identify key design indicators, at both project and firm level; and (c) use DPMs to provide a balanced scorecard for design performance.performance indicators, design integration, design indicators, construction industry

    The 25 October 2010 Mentawai tsunami earthquake (M_w 7.8) and the tsunami hazard presented by shallow megathrust ruptures

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    The 25 October 2010 Mentawai, Indonesia earthquake (M_w 7.8) ruptured the shallow portion of the subduction zone seaward of the Mentawai islands, off-shore of Sumatra, generating 3 to 9 m tsunami run-up along southwestern coasts of the Pagai Islands that took at least 431 lives. Analyses of teleseismic P, SH and Rayleigh waves for finite-fault source rupture characteristics indicate ∼90 s rupture duration with a low rupture velocity of ∼1.5 km/s on the 10° dipping megathrust, with total slip of 2–4 m over an ∼100 km long source region. The seismic moment-scaled energy release is 1.4 × 10^(−6), lower than 2.4 × 10^(−6) found for the 17 July 2006 Java tsunami earthquake (M_w 7.8). The Mentawai event ruptured up-dip of the slip region of the 12 September 2007 Kepulauan earthquake (M_w 7.9), and together with the 4 January 1907 (M 7.6) tsunami earthquake located seaward of Simeulue Island to the northwest along the arc, demonstrates the significant tsunami generation potential for shallow megathrust ruptures in regions up-dip of great underthrusting events in Indonesia and elsewhere

    A great earthquake doublet and seismic stress transfer cycle in the central Kuril islands

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    Temporal variations of the frictional resistance on subduction-zone plate boundary faults associated with the stick–slip cycle of large interplate earthquakes are thought to modulate the stress regime and earthquake activity within the subducting oceanic plate. Here we report on two great earthquakes that occurred near the Kuril islands, which shed light on this process and demonstrate the enhanced seismic hazard accompanying triggered faulting. On 15 November 2006, an event of moment magnitude 8.3 ruptured the shallow-dipping plate boundary along which the Pacific plate descends beneath the central Kuril arc. The thrust ruptured a seismic gap that previously had uncertain seismogenic potential, although the earlier occurrence of outer-rise compressional events had suggested the presence of frictional resistance. Within minutes of this large underthrusting event, intraplate extensional earthquakes commenced in the outer rise region seaward of the Kuril trench, and on 13 January 2007, an event of moment magnitude 8.1 ruptured a normal fault extending through the upper portion of the Pacific plate, producing one of the largest recorded shallow extensional earthquakes. This energetic earthquake sequence demonstrates the stress transfer process within the subducting lithosphere, and the distinct rupture characteristics of these great earthquakes illuminate differences in seismogenic properties and seismic hazard of such interplate and intraplate faults

    Mesons from global Anti-de Sitter space

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    In the context of gauge/gravity duality, we study both probe D7-- and probe D5--branes in global Anti-de Sitter space. The dual field theory is N=4 theory on R x S^3 with added flavour. The branes undergo a geometrical phase transition in this geometry as function of the bare quark mass m_q in units of 1/R with R the S^3 radius. The meson spectra are obtained from fluctuations of the brane probes. First, we study them numerically for finite quark mass through the phase transition. Moreover, at zero quark mass we calculate the meson spectra analytically both in supergravity and in free field theory on R x S^3 and find that the results match: For the chiral primaries, the lowest level is given by the zero point energy or by the scaling dimension of the operator corresponding to the fluctuations, respectively. The higher levels are equidistant. Similar results apply to the descendents. Our results confirm the physical interpretation that the mesons cannot pair-produce any further when their zero-point energy exceeds their binding energy.Comment: 43 pages, 8 figures, references edited, few typos corrected, updated to match the published versio
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