3,623,180 research outputs found
Subjective evaluation of an emerging theory of low-frequency sound source localization in closed acoustic spaces
An earlier reported theory of low-frequency sound-source localization within closed acoustic spaces proposed that virtual image acuity is strongly dependent on sufficient inter-arrival time between a direct sound and its first reflection. This current study aims to test the theory’s predictions by subjective experiment where participants are required to indicate perceived sound source direction, but without knowledge of loudspeaker location. Test signals of frequencies 40 Hz to 115 Hz take the form of either windowed sine or square waves. Results confirm broad agreement with theoretical expectations and support the conjecture, contrary to common expectation, that low-frequency sound localization within the context of closed acoustic spaces is possible, although strongly dependent on system configuration and size of a listening space
Hill of Banchory Geothermal Energy Project Feasibility Study Report
This feasibility study explored the potential for a deep geothermal heat project at Hill of Banchory, Aberdeenshire. The geology of the Hill of Fare, to the north of Banchory, gives cause to believe it has good geothermal potential, while the Hill of Banchory heat network, situated on the northern side of the town, offers a ready-made heat customer.
The partners in the consortium consisted of academics and developers with relevant expertise in deep geothermal energy, heat networks, and financial analysis, together with representatives of local Government. They conducted geological fieldwork around the Hill of Fare, engaged with local residents to establish their attitudes to geothermal energy, and built business models to predict the conditions under which the heat network at Hill of Banchory would be commercial if it utilised heat from the proposed geothermal well. They also estimated the potential carbon emission reductions that could be achieved by using deep geothermal energy, both at Hill of Banchory and more widely
Stability Limits in Resonant Planetary Systems
The relationship between the boundaries for Hill and Lagrange stability in
orbital element space is modified in the case of resonantly interacting
planets. Hill stability requires the ordering of the planets to remain constant
while Lagrange stability also requires all planets to remain bound to the
central star. The Hill stability boundary is defined analytically, but no
equations exist to define the Lagrange boundary, so we perform numerical
experiments to estimate the location of this boundary. To explore the effect of
resonances, we consider orbital element space near the conditions in the HD
82943 and 55 Cnc systems. Previous studies have shown that, for non-resonant
systems, the two stability boundaries are nearly coincident. However the Hill
stability formula are not applicable to resonant systems, and our investigation
shows how the two boundaries diverge in the presence of a mean-motion
resonance, while confirming that the Hill and Lagrange boundaries are similar
otherwise. In resonance the region of stability is larger than the domain
defined by the analytic formula for Hill stability. We find that nearly all
known resonant interactions currently lie in this extra stable region, i.e.
where the orbits would be unstable according to the non-resonant Hill stability
formula. This result bears on the dynamical packing of planetary systems,
showing how quantifying planetary systems' dynamical interactions (such as
proximity to the Hill-stability boundary) provides new constraints on planet
formation models.Comment: 13 pages, 3 figures, 2 tables, accepted for publication in ApJ
Letters. A version with full resolution figures is available at
http://www.lpl.arizona.edu/~rory/research/xsp/resstab.pd
Direct numerical simulation of a turbulent flow over an axisymmetric hill
Direct numerical simulation (DNS) of a turbulent flow over an axisymmetric hill has been carried out to
study the three-dimensional flow separation and reattachment that occur on the lee-side of the
geometry. The flow Reynolds number is ReH = 6500, based on free-stream quantities and hill height
(H). A synthetic inflow boundary condition, combined with a data feed-in method, has been used to
generate the turbulent boundary layer approaching to the hill. The simulation has been run using a
typical DNS resolution of DxĂľ ÂĽ 12:5; DzĂľ ÂĽ 6:5, and DyĂľ1
ÂĽ 1:0 and about 10 points in the viscous
sublayer. It was found that a separation bubble exists at the foot of the wind-side of the hill and the
incoming turbulent boundary layer flow undergoes re-laminarization process around the crest of the hill.
These lead to a significant flow separation at the lee-side of the hill, where a very large primary separation
bubble embedded with a smaller secondary separations have been captured. The present low-Re
simulation reveals some flow features that are not observed by high-Re experiments, thus is useful for
future experimental studies
Studies on termite hill and lime as partial replacement for cement in plastering
This study investigated the compressive strength and water absorption capacity of 50�50�50mm mortar cubes made from
mixes containing lime, termite hill and cement and sand.Two mix ratios (1:4 and 1:6) and varying binder replacements of cement
with lime or termite hill amounting to 0%, 10%, 20%, 30%, 40% and 50% were used.Test results showed that the compressive
strength of the mortar cubes increases with age and decreases with increasing percentage replacement of cement with lime and
termite hill.However, for mix ratio 1:6, up to 20% replacement of cement with either lime or termite hill, all the mortar cubes had
the same strength; subsequently, the termite hill exhibited a higher compressive strength.For mix ratio 1:4, mortar cubes made from
lime/cement and termite hill/cement mixtures had the same strength at 50% replacement.Generally, water absorption is higher in mixtures containing lime (18.10% and 14.20% for mix ratios 1:6 and 1:4, respectively, both at 50% replacement level) than those containing termite hill (16.10% and 13.02% for mix ratios 1:6 and 1:4, respectively, both at 50% replacement level). Termite hills
seem to be promising as a suitable, locally available housing material for plastering.
r 2005 Elsevier Ltd.All rights reserved
Exchange, Conflict and Coercion: The Ritual Dynamics of the Notting Hill Carnival Past and Present
This study investigates patterns of social relationships involving the Notting Hill Carnival. Two theoretical approaches are employed elementary relations theory and structural ritualization theory - to explain how the carnival has been strategically used in very different ways by various groups to accomplish their objectives. We suggest the Notting Hill Carnival is a special collective ritual event that has played a crucial role in three quite different structured arrangements involving coercion, conflict, and exchange since its beginning in Trinidad and subsequently in London. Four time periods where distinct changes in the nature of these relationships have occurred are examined: (1) 1800s Trinidad; (2) the Notting Hill Carnival from 1965-1970; (3) the Notting Hill Carnival from 1971-1989; and (4) the Notting Hill Carnival from 1990-present. This study contributes to the existing literature by focusing on how ritual and these types of relationships are intertwined in the production of the carnival. Implications of this research and possible directions for future research are also discussed
Cleveland Hill Union Free School District and Cleveland Hill Education Association
Fact-finding proceeding between Cleveland Hill Union Free School District and Cleveland Hill Education Association. PERB Case No. M 2007-062. Before: Adam Kaufman, Esq. Fact Finde
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