The topic of urban planning linked to the growth of smart cities is now quite common also in the urban-sociological debate. Recent studies (Besselaar, Koizumi, 2005; Fistola, 2010) identify the main ...focus of the smart city no longer exclusively in the strategic role played by ICT infrastructures, but above all in the factors enabling urban growth, defined as the ability to stimulate innovative urban developments, along with an increasing attention to the environment, eco-design, improved living levels, as well as the "bio-socio-environmental capital" (Corbisiero, 2013). Based on this theoretical background, the paper highlights the results of a research conducted in Naples on the empirical case of the "Centro Direzionale". It is an intervention of urban design of considerable impact on the city. The design and construction of the Centro Direzionale of Naples is, in fact, an archetype of the smart city; a primal testing of "urban intelligence" in terms of transport systems, infrastructure, logistics, systems for energy efficiency and technology. More generally, a good practice of city administration and of exploitation of strategic spatial planning.
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bstract
We start by revisiting the problem of finding BPS solutions in
$$ \mathcal{N} $$
N
= 4 SU (2) × SU (2) gauged supergravity. We report on a new supersymmetric solution in the Abelian sector ...of the theory, which describes a soliton that is regular everywhere. The solution is 1/4 BPS and can be obtained from a double analytic continuation of a planar solution found by Klemm in hep-th/9810090. Also in the Abelian sector, but now for a spherically symmetric ansatz we find a new solution whose supersymmetric nature was overlooked in the previous literature. Then, we move to the non-Abelian sector of the theory by considering the meron ansatz for SU (2). We construct electric-meronic and double-meron solutions and show that the latter also leads to 1/4 BPS configurations that are singular and acquire an extra conformal Killing vector. We then move beyond the supergravity embedding of this theory by modifying the self-interaction of the scalar, but still within the same meron ansatz for a single gauge field, which is dilatonically coupled with the scalar. We construct exact black holes for two families of self-interactions that admit topologically Lifshitz black holes, as well as other black holes with interesting causal structures and asymptotic behavior. We analyze some thermal properties of these spacetimes.
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bstract
We find both analytical and numerical solutions of SU(2) Yang-Mills with an adjoint Higgs field within both closed and open tubes whose sections are spherical caps. This geometry admits a ...smooth limit in which the space-like metric is flat and, moreover, allows one to use analytical tools which in the flat case are not available. Some of the analytic configurations, in the limit of vanishing Higgs coupling, correspond to magnetic monopoles and dyons living within this tube-shaped domain. However, unlike what happens in the standard case, analytical solutions can also be found in the case in which the Higgs coupling is non-vanishing. We further show that the system admits long-lived breathers.
We present novel analytic hairy black holes with a flat base manifold in the (3+1)-dimensional Einstein SU(2)-Skyrme system with negative cosmological constant. We also construct (3+1)-dimensional ...black strings in the Einstein SU(2)-nonlinear sigma model theory with negative cosmological constant. The geometry of these black strings is a three-dimensional charged Bañados-Teitelboim-Zanelli black hole times a line, without any warp factor. The thermodynamics of these configurations (and its dependence on the discrete hairy parameter) is analyzed in details. A very rich phase diagram emerges.
We show that the (3 + 1)-dimensional gauged nonlinear sigma model minimally coupled to a U(1) gauge field possesses analytic solutions representing gauged solitons at finite baryon density whose ...electromagnetic field is a force-free plasma. These gauged solitons manifest a crystalline structure and generate in a very natural way persistent currents able to support force-free plasma electromagnetic fields. The trajectories of charged test particles moving within these configurations can be characterized. Quite surprisingly, despite the nonintegrable nature of the theory, some of the perturbations of these gauged solitons allow one to identify a proper resurgent parameter. In particular, the perturbations of the solitons profile are related to the Lamé operator. On the other hand, the electromagnetic perturbations on the configurations satisfy a two-dimensional effective Schrödinger equation, where the soliton's background interacts with the electromagnetic perturbations through an effective two-dimensional periodic potential. We studied numerically the band energy spectrum for different values of the free parameters of the theory and we found that band gaps are modulated by the potential strength. Finally we compare our crystal solutions with those of the (1 + 1)-dimensional Gross-Neveu model.
We find new exact solutions of the Abelian-Higgs model coupled to general relativity, characterized by a nonvanishing superconducting current. The solutions correspond to pp-waves, AdS waves, and ...Kundt spaces, for which both the Maxwell field and the gradient of the phase of the scalar are aligned with the null direction defining these spaces. In the Kundt family, the geometry of the two-dimensional surfaces orthogonal to the superconducting current is determined by the solutions of the two-dimensional Liouville equation, and in consequence, these surfaces are of constant curvature, as it occurs in a vacuum. The solution to the Liouville equation also acts as a potential for the Maxwell field, which we integrate into a closed-form. Using these results, we show that the combined effects of the gravitational and scalar interactions can confine the electromagnetic field within a bounded region in the surfaces transverse to the current.
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