46,099 research outputs found
Information-entropic analysis of Korteweg--de Vries solitons in the quark-gluon plasma
Solitary waves propagation of baryonic density perturbations, ruled by the
Korteweg--de Vries equation in a mean-field quark-gluon plasma model, are
investigated from the point of view of the theory of information. A recently
proposed continuous logarithmic measure of information, called configurational
entropy, is used to derive the soliton width, defining the pulse, for which the
informational content of the soliton spatial profile is more compressed, in the
Shannon's sense.Comment: 6 pages, 1 figur
Strategies for building pathology reports in an urban rehabilitation process: Project of the Old City Centre of Coimbra
The increasing interest on architectural heritage associated to the recognised building value, at economic, social and cultural levels have stimulated, in the recent decades, the urban rehabilitation and renovation o several cities in Europe.
Despite the strategy or method adopted in a city renovation process, its efficiency depends mainly on: type of buildings (structural systems, construction techniques and materials); intervention level (singular buildings, groups of buildings, urban zones, etc.); and, project objective (risk assessment, decision making to support future rehabilitation projects, definition of council maintenance policies, etc.).
In what concerns large renovation programs of old city centres, choosing the most adequate approach for inspection, appraisal and diagnosis is a complex task that can determine the success or failure of the project purpose.
This paper describes the preparation phase of the inspection of 700 buildings located in the old city centre of Coimbra (Portugal), where a global renovation process is planned for the forthcoming years.
In the scope of the renovation and rehabilitation process, the city council contract a complete identification and inspection survey of the buildings, directed on three different domains: (a) architectural typologies, (b) constructive and pathological condition of buildings, and (c) socio-demographic characterisation, of this part of the city. It will be present the check-lists developed and some of the obtained results on point (b), related to roofing systems, and exterior façades.
This diagnosis procedure shows that the inspection results quality is quite dependent on the items surveyed for each construction element (roof, façade, internal members, installation efficiency), as well as on the possibility of their correlation for a single building. The adopted method has been applied on 70% of the buildings inspected within the project perimeter.
Further treatment of the inspection and appraisal data will allow the developing pathology reports and list repair actions, and estimating rehabilitation costs. It will also help to produce defect level diagrams and seismic building risk maps, but, most important, to improve and guide a renewal strategy and intervention methodology for old buildings
Dynamical Evolution of an Unstable Gravastar with Zero Mass
Using the conventional gravastar model, that is, an object constituted by two
components where one of them is a massive infinitely thin shell and the other
one is a de Sitter interior spacetime, we physically interpret a solution
characterized by a zero Schwarzschild mass. No stable gravastar is formed and
it collapses without forming an event horizon, originating what we call a
massive non-gravitational object. The most surprise here is that the collapse
occurs with an exterior de Sitter vacuum spacetime. This creates an object
which does not interact gravitationally with an outside test particle and it
may evolve to a point-like topological defect.Comment: 8 pages, 10 figures, to appear in Astrophysics and Space Scienc
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