18,355 research outputs found

    Assessing the potential for reopening a building stone quarry : Newbigging Sandstone Quarry, Fife

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    Newbigging Sandstone Quarry in Fife is one of a number of former quarries in the Burntisland- Aberdour district which exploited the pale-coloured Grange Sandstone from Lower Carboniferous rocks. The quarry supplied building stone from the late 19th century, working intermittently from 1914 until closure in 1937, and again when reopened in the 1970s to the 1990s. The stone was primarily used locally and to supply the nearby markets in the Scottish Central Belt. Historical evidence indicates that prior to sandstone extraction, the area was dominated by largescale quarrying and mining of limestone, and substantial sandstone quarrying is likely to have begun after the arrival of the main railway line in 1890. It is probable that removal of the sandstone was directly associated with limestone exploitation, and that the quarried sandstone was effectively a by-product of limestone production. Sandstone extraction was probably viable due to the existing limestone quarry infrastructure (workforce, equipment, transportation) and the high demand for building stone in Central Scotland in the late 19th century. The geology within Newbigging Sandstone Quarry is dominated by thick-bedded uniform sandstone with a wide joint spacing, well-suited for obtaining large blocks. However, a mudstone (shale) band is likely to be present within a few metres of the principal (north) face of the quarry, around which the sandstone bed thickness and quality is likely to decrease. The mudstone bed forms a plane sloping at a shallow angle to the north, so that expansion of the quarry in this direction is likely to encounter a considerable volume of poor quality stone. Additionally, an east-west trending fault is present approximately 100 metres north of the quarry face, which is also likely to be associated with poor quality (fractured) stone

    Revisión tecnológica del aprendizaje de idiomas asistido por ordenador: una perspectiva cronológica

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    El presente artículo aborda la evolución y el avance de las tecnologías del aprendizaje de lenguas asistido por ordenador (CALL por sus siglas en inglés, que corresponden a Computer- Assisted Language Learning) desde una perspectiva histórica. Esta revisión de la literatura sobre tecnologías del aprendizaje de lenguas asistido por ordenador comienza con la definición del concepto de CALL y otros términos relacionados, entre los que podemos destacar CAI, CAL, CALI, CALICO, CALT, CAT, CBT, CMC o CMI, para posteriormente analizar las primeras iniciativas de implementación del aprendizaje de lenguas asistido por ordenador en las décadas de 1950 y 1960, avanzando posteriormente a las décadas de las computadoras centrales y las microcomputadoras. En última instancia, se revisan las tecnologías emergentes en el siglo XXI, especialmente tras la irrupción de Internet, donde se presentan el impacto del e-learning, b-learning, las tecnologías de la Web 2.0, las redes sociales e incluso el aprendizaje de lenguas asistido por robots.The main focus of this paper is on the advancement of technologies in Computer-Assisted Language Learning (CALL) from a historical perspective. The review starts by defining CALL and its related terminology, highlighting the first CALL attempts in 1950s and 1960s, and then moving to other decades of mainframes and microcomputers. At the final step, emerging technologies in 21st century will be reviewed

    Canonical circuit quantization with linear nonreciprocal devices

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    Nonreciprocal devices effectively mimic the breaking of time-reversal symmetry for the subspace of dynamical variables that they couple, and can be used to create chiral information processing networks. We study the systematic inclusion of ideal gyrators and circulators into Lagrangian and Hamiltonian descriptions of lumped-element electrical networks. The proposed theory is of wide applicability in general nonreciprocal networks on the quantum regime. We apply it to pedagogical and pathological examples of circuits containing Josephson junctions and ideal nonreciprocal elements described by admittance matrices, and compare it with the more involved treatment of circuits based on nonreciprocal devices characterized by impedance or scattering matrices. Finally, we discuss the dual quantization of circuits containing phase-slip junctions and nonreciprocal devices.Comment: 12 pages, 4 figures; changes made to match the accepted version in PR

    Arp 220 - IC 4553/4: understanding the system and diagnosing the ISM

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    Arp220 is a nearby system in final stages of galaxy merger with powerful ongoing star-formation at and surrounding the two nuclei. Arp 220 was detected in HI absorption and OH Megamaser emission and later recognized as the nearest ultra-luminous infrared galaxy also showing powerful molecular and X-ray emissions. In this paper we review the available radio and mm-wave observational data of Arp 220 in order to obtain an integrated picture of the dense interstellar medium that forms the location of the powerful star-formation at the two nuclei.Comment: 9 pages, 4 figures, to appear in: IAU Symposium 242 Astrophysical Masers and their Environment

    Analytical solution to DGLAP integro-differential equation in a simple toy-model with a fixed gauge coupling

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    We consider a simple model for QCD dynamics in which DGLAP integro-differential equation may be solved analytically. This is a gauge model which possesses dominant evolution of gauge boson (gluon) distribution and in which the gauge coupling does not run. This may be N=4{\cal N} =4 supersymmetric gauge theory with softly broken supersymmetry, other finite supersymmetric gauge theory with lower level of supersymmetry, or topological Chern-Simons field theories. We maintain only one term in the splitting function of unintegrated gluon distribution and solve DGLAP analytically for this simplified splitting function. The solution is found by use of the Cauchy integral formula. The solution restricts form of the unintegrated gluon distribution as function of transfer momentum and of Bjorken xx. Then we consider an almost realistic splitting function of unintegrated gluon distribution as an input to DGLAP equation and solve it by the same method which we have developed to solve DGLAP equation for the toy-model. We study a result obtained for the realistic gluon distribution and find a singular Bessel-like behaviour in the vicinity of the point x=0x=0 and a smooth behaviour in the vicinity of the point x=1.x=1.Comment: 25 page
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