17,656 research outputs found

    The Canadian Constitutional Amendment Process

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    The artist speaks: the interview as documentation

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    Nearly every exhibition catalogue now contains an interview with, or related statement by, the artist. How and why did this become the norm? The increasing popularity of the artist's words is traced back in this article to its roots in Romanticism, the rise of the mass media and the cult of the avant-garde artist. The value and reliability of the transcribed and printed words is questioned and a bibliography of published interviews with artists follows

    Strong-field tidal distortions of rotating black holes: II. Horizon dynamics from eccentric and inclined orbits

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    In a previous paper, we developed tools for studying the horizon geometry of a Kerr black hole that is tidally distorted by a binary companion using techniques that require large mass ratios but can be applied to any bound orbit and allow for arbitrary black hole spin. We now apply these tools to generic Kerr black hole orbits. This allows us to investigate horizon dynamics: the tidal field perturbing the horizon's geometry varies over a generic orbit, with significant variations for eccentric orbits. Many of the features of the horizon's behavior found previously carry over to the dynamical case in a natural way. In particular, we find significant offsets between the applied tide and the horizon's response. This leads to bulging in the horizon's geometry which can lag or lead the orbit, depending upon the hole's rotation and the orbit's geometry. An interesting and apparently new feature we find are small-amplitude, high-frequency oscillations in the horizon's response. We have not been able to identify a mechanism for producing these oscillations, but find that they appear most clearly when rapidly rotating black holes are distorted by very strong-field orbits.Comment: 24 pages, 15 figures. Final accepted version, to appear in Phys. Rev.

    Practical applications of data mining in plant monitoring and diagnostics

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    Using available expert knowledge in conjunction with a structured process of data mining, characteristics observed in captured condition monitoring data, representing characteristics of plant operation may be understood, explained and quantified. Knowledge and understanding of satisfactory and unsatisfactory plant condition can be gained and made explicit from the analysis of data observations and subsequently used to form the basis of condition assessment and diagnostic rules/models implemented in decision support systems supporting plant maintenance. This paper proposes a data mining method for the analysis of condition monitoring data, and demonstrates this method in its discovery of useful knowledge from trip coil data captured from a population of in-service distribution circuit breakers and empirical UHF data captured from laboratory experiments simulating partial discharge defects typically found in HV transformers. This discovered knowledge then forms the basis of two separate decision support systems for the condition assessment/defect clasification of these respective plant items

    A New Bot Fly Species (Diptera: Oestridae) From Central Texas

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    The bot fly Cephenemyia albina (Diptera: Oestridae) is described from a relict pine forest in east-central Texas. This species presumably lives as a parasitic larva in the throat of white-tailed deer as do its two close relatives previously reported from both Texas and the Great Lakes region (C. phobifera (Clark) and C. jellisoni Townsend). Only the adult male is currently known

    Orthotropic cyclic stress-softening model for pure shear during repeated loading and unloading

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    We derive an orthotropic model to describe the cyclic stress softening of a carbon-filled rubber vulcanizate through multiple stress-strain cycles with increasing values of the maximum strain. We specialize the deformation to pure shear loading. As a result of strain-induced anisotropy following on from initial primary loading, the material may subsequently be described as orthotropic because in pure shear there are three different principal stretches so that the strain-induced anisotropy of the stress response is different in each of these three directions. We derive non-linear orthotropic models for the elastic response, stress relaxation and residual strain to model accurately the inelastic features associated with cyclic stress softening. We then develop an orthotropic version of the Arruda-Boyce eight-chain model of elasticity and then combine it with the ideas previously developed in this paper to produce an orthotropic constitutive relation for the cyclic stress softening of a carbon-filled rubber vulcanizate. The model developed here includes the widely occurring effects of hysteresis, stress-relaxation and residual strain. The model is found to compare well with experimental data
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