18,355 research outputs found
Assessing the potential for reopening a building stone quarry : Newbigging Sandstone Quarry, Fife
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
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
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
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
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 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 . 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 and a smooth behaviour
in the vicinity of the point Comment: 25 page
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