23,171 research outputs found
ON INTERACTION BETWEEN FALLING BODIES AND THE SURROUNDING FLUID
Interactions between a finite number of bodies and the surrounding fluid, in a channel for instance, are investigated theoretically. In the planar model here the bodies or modelled grains are thin solid bodies free to move in a nearly parallel formation within a quasi-inviscid fluid. The investigation involves numerical and analytical studies and comparisons. The three main features that appear are a linear instability about a state of uniform motion, a clashing of the bodies (or of a body with a side wall) within a finite scaled time when nonlinear interaction takes effect, and a continuum-limit description of the body–fluid interaction holding for the case of many bodies
IYV Global Evaluation
This is a report on the global evaluation of the International Year of Volunteers (IYV)
UK-wide evaluation of the Millennium Volunteers Programme
The Millennium Volunteers programme is a UK-wide government supported initiative designed to promote sustained volunteering among young people aged 16-24
Light-Cone Broadening and TeV Scale Extra Dimensions
We examine the effect of light-cone broadening induced by quantum-gravity
foam in the context of theories with ``large'' extra dimensions stretching
between two parallel brane worlds. We consider the propagation of photon probes
on one of the branes, including the response to graviton fluctuations, from
both field- and string-theoretical viewpoints. In the latter approach, the
dominant source of light-cone broadening may be the recoil of the D-brane,
which scales linearly with the string coupling. Astrophysical constraints then
place strong restrictions on consistent string models of macroscopic extra
dimensions. The broadening we find in the field-theoretical picture seems to be
close to the current sensitivity of gravity-wave interferometers, and therefore
could perhaps be tested experimentally in the foreseeable future.Comment: 12 pages REVTeX, 2 axodraw figures incorporate
Visualization of three dimensional data
The objective of research is to characterize patterns of errors observers make when relating the judged exocentric direction of a target presented on a perspective display to their egocentric sense of visual direction. This type of spatial task is commonly faced by operators of telerobotic systems when using a map-like display of their workspace to determine the visual location and orientation of objects seen by direct view. It is also essentially the same task as faced by an aircraft pilot using a cockpit perspective traffic display of his surrounding airspace to locate traffic out his windows. The results of the current study clearly show that the visual direction is a significantly biased metric of virtual space presented by flat panel perspective displays. Modeling and explanation of the causes of the observed biases will allow design of compensated perspective displays
Visual direction as a metric of virtual space
Two experiments examine the abilities of ten subjects to visualize directions shown on a perspective display. Subjects indicated their perceived directions by adjusting a head-mounted cursor to correspond to the direction depicted on the display. This task is required of telerobotic operators who use map-like pictures of their workspace to determine the direction of objects seen by direct view. Results show significant open loop judgment biases that may be composed of errors arising from misinterpretation of the map geometry and overestimation of gaze direction
Impact of the DRA Citizenship and Identity Documentation Requirement on Medi-Cal: Findings From Site Visits to Six Counties
Evaluates how the 2006 requirement for Medicaid beneficiaries to present proof of citizenship affected the workloads of California counties and enrollees' and applicants' access to Medi-Cal. Examines stakeholders' views of the requirement
Virtual reality learning resources in building pathology
Building surveying students must be capable of analysing the condition of buildings and their components and, where this falls below an agreed standard, make recommendations for their repair. Hence university courses must provide opportunities for students to learn about the main causes of deterioration. Fieldwork exercises are essential but there are often problems locating appropriate buildings, programming visits to satisfy course timetables and complying with health and safety requirements. Whilst virtual surveys of existing buildings are not considered to be a substitute for real-life educational visits, this paper critically examines the development of a novel building pathology educational resource. Alternative technologies for creating digital panoramas are examined, prior to the development of an interactive case study, which enables students to conduct an on-line survey of a Grade 1 listed 16th Century hunting lodge. 360 degree panoramic scenes are linked with hot spots to create an interactive virtual tour of the building. The paper considers how virtual resources can be embedded within the curriculum, gauges tutor reaction to case study materials and identifies opportunities for the development of a suite of building pathology educational media-rich learning materials
Thermodynamic versus statistical nonequivalence of ensembles for the mean-field Blume-Emery-Griffiths model
We illustrate a novel characterization of nonequivalent statistical
mechanical ensembles using the mean-field Blume-Emery-Griffiths (BEG) model as
a test model. The novel characterization takes effect at the level of the
microcanonical and canonical equilibrium distributions of states. For this
reason it may be viewed as a statistical characterization of nonequivalent
ensembles which extends and complements the common thermodynamic
characterization of nonequivalent ensembles based on nonconcave anomalies of
the microcanonical entropy. By computing numerically both the microcanonical
and canonical sets of equilibrium distributions of states of the BEG model, we
show that for values of the mean energy where the microcanonical entropy is
nonconcave, the microcanonical distributions of states are nowhere realized in
the canonical ensemble. Moreover, we show that for values of the mean energy
where the microcanonical entropy is strictly concave, the equilibrium
microcanonical distributions of states can be put in one-to-one correspondence
with equivalent canonical equilibrium distributions of states. Our numerical
computations illustrate general results relating thermodynamic and statistical
equivalence and nonequivalence of ensembles proved by Ellis, Haven, and
Turkington [J. Stat. Phys. 101, 999 (2000)].Comment: 13 pages, 4 figures, minor typos corrected and one reference adde
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