(2+1)-Dimensional Black Hole with Coulomb-like Field

A (2+1)-static black hole solution with a nonlinear electric field is derived. The source to the Einstein equations is a nonlinear electrodynamics, satisfying the weak energy conditions, and it is such that the energy momentum tensor is traceless. The obtained solution is singular at the origin of coordinates. The derived electric field E(r) is given by $E(r)=q/r^2$, thus it has the Coulomb form of a point charge in the Minkowski spacetime. This solution describes charged (anti)--de Sitter spaces. An interesting asymptotically flat solution arises for $\Lambda=0$.Comment: 6 pages, Latex, Phys. Lett. B. 484, 154 (2000

Regular (2+1)-dimensional black holes within non-linear Electrodynamics

(2+1)-regular static black hole solutions with a nonlinear electric field are derived. The source to the Einstein equations is an energy momentum tensor of nonlinear electrodynamics, which satisfies the weak energy conditions and in the weak field limit becomes the (2+1)-Maxwell field tensor. The derived class of solutions is regular; the metric, curvature invariants and electric field are regular everywhere. The metric becomes, for a vanishing parameter, the (2+1)-static charged BTZ solution. A general procedure to derive solutions for the static BTZ (2+1)-spacetime, for any nonlinear Lagrangian depending on the electric field is formulated; for relevant electric fields one requires the fulfillment of the weak energy conditions.Comment: 5 pages, Latex, 2 figure

Three Dimensional Black Hole Coupled to the Born-Infeld Electrodynamics

A nonlinear charged version of the (2+1)-anti de Sitter black hole solution is derived. The source to the Einstein equations is a Born-Infeld electromagnetic field, which in the weak field limit becomes the (2+1)-Maxwell field. The obtained Einstein-Born-Infeld solution for certain range of the parameters (mass, charge, cosmological and Born-Infeld constants) represent a static circularly symmetric black hole. Although the covariant metric components and the electric field do not exhibit a singular behavior at r=0 the curvature invariants are singular at that point.Comment: 5 pages, 1 figure, Latex. To appear in Phys. Lett.

Obstáculos y motivaciones para viviendas sociales en base a bolsas de tierra en Chile: implicaciones en energía, ambiente, económicas y normativas

Chile presents a social housing deficit that needs to be addressed with solutions that increase habitability and environmental benefits. This paperaddresses the benefits of implementing earthbag buildings as an option to mitigate the existing social housing deficit in Chile. A literature reviewpresents details on the use of earthbag buildings around the world, and motivations and obstacles for implementing earthbag buildings in Chile. Inparticular, a case study was simulated to compare an earthbag social house to a reinforced brick masonry social house in terms of environmental andeconomic performances such as CO2 emissions, energy and costs. It is concluded that both alternatives generate similar CO2 emissions, but the earthbagsocial house can save up to 20% of energy during its life cycle. In economic terms, the earthbag social house generates savings of 50% and 38% for initialinvestment and life cycle cost, respectively, compared to the reinforced brick masonry social house. The implementation of earthbag social housingprojects would be encouraged by the development of a Chilean building code for earthbag design that provides guidance on the safe use of thistechnique in a seismic country.Chile presenta un déficit habitacional en viviendas sociales que necesita ser abordado con soluciones que incrementen la habitabilidad y beneficiosambientales. Este trabajo aborda los beneficios de implementar viviendas en base a bolsas de tierra como una opción para mitigar el déficit habitacionalde viviendas sociales existente en Chile. Una revisión bibliográfica presenta detalles en el uso de viviendas en base a bolsas de tierra alrededor delmundo, y motivaciones y obstáculos para la implementación de viviendas en base a bolsas de tierra en Chile. En particular, un caso de estudio fuesimulado para comparar una vivienda social en base a bolsas de tierra a una vivienda social de albañilería reforzada en términos de desempeñosambientales y económicos tales como emisiones de CO2, energía y costos. Es concluido que ambas alternativas generan emisiones similares de CO2, perola vivienda social en base a bolsas de tierra puede ahorrar hasta un 20% de energía durante su ciclo de vida. En términos económicos, la vivienda socialen base a bolsas de tierra genera ahorros de 50% y 38% para la inversión inicial y costos en ciclo de vida, respectivamente, comparado a la vivienda socialde albañilería reforzada. La implementación de proyectos de vivienda social en base a bolsas de tierra sería incentivada por el desarrollo de unanormativa chilena de diseño en base a bolsas de tierra que provea guía en el uso seguro de esta técnica en un país sísmico

Obstáculos y motivaciones para viviendas sociales en base a bolsas de tierra en Chile: implicaciones en energía, ambiente, económicas y normativas

Chile presents a social housing deficit that needs to be addressed with solutions that increase habitability and environmental benefits. This paper addresses the benefits of implementing earthbag buildings as an option to mitigate the existing social housing deficit in Chile. A literature review presents details on the use of earthbag buildings around the world, and motivations and obstacles for implementing earthbag buildings in Chile. In particular, a case study was simulated to compare an earthbag social house to a reinforced brick masonry social house in terms of environmental and economic performances such as CO2 emissions, energy and costs. It is concluded that both alternatives generate similar CO2 emissions, but the earthbag social house can save up to 20% of energy during its life cycle. In economic terms, the earthbag social house generates savings of 50% and 38% for initial investment and life cycle cost, respectively, compared to the reinforced brick masonry social house. The implementation of earthbag social housing projects would be encouraged by the development of a Chilean building code for earthbag design that provides guidance on the safe use of this technique in a seismic country.   Chile presenta un déficit habitacional en viviendas sociales que necesita ser abordado con soluciones que incrementen la habitabilidad y beneficios ambientales. Este trabajo aborda los beneficios de implementar viviendas en base a bolsas de tierra como una opción para mitigar el déficit habitacional de viviendas sociales existente en Chile. Una revisión bibliográfica presenta detalles en el uso de viviendas en base a bolsas de tierra alrededor del mundo, y motivaciones y obstáculos para la implementación de viviendas en base a bolsas de tierra en Chile. En particular, un caso de estudio fue simulado para comparar una vivienda social en base a bolsas de tierra a una vivienda social de albañilería reforzada en términos de desempeños ambientales y económicos tales como emisiones de CO2, energía y costos. Es concluido que ambas alternativas generan emisiones similares de CO2, pero la vivienda social en base a bolsas de tierra puede ahorrar hasta un 20% de energía durante su ciclo de vida. En términos económicos, la vivienda social en base a bolsas de tierra genera ahorros de 50% y 38% para la inversión inicial y costos en ciclo de vida, respectivamente, comparado a la vivienda social de albañilería reforzada. La implementación de proyectos de vivienda social en base a bolsas de tierra sería incentivada por el desarrollo de una normativa chilena de diseño en base a bolsas de tierra que provea guía en el uso seguro de esta técnica en un país sísmico.&nbsp

Topological Born-Infeld-dilaton black holes

We construct a new analytic solution of Einstein-Born-Infeld-dilaton theory in the presence of Liouville-type potentials for the dilaton field. These solutions describe dilaton black holes with nontrivial topology and nonlinear electrodynamics. Black hole horizons and cosmological horizons in these spacetimes, can be a two-dimensional positive, zero or negative constant curvature surface. The asymptotic behavior of these solutions are neither flat nor (A)dS. We calculate the conserved and thermodynamic quantities of these solutions and verify that these quantities satisfy the first law of black hole thermodynamics.Comment: 15 pages, 7 figures, references added, to appear in Phys. Lett.

Regular charged black hole construction in 2+1 -dimensions

It is well-known that unlike its chargeless version the charged Banados-Teitelboim-Zanelli (BTZ) black hole solution in 2+1- dimensional spacetime is singular. We construct a charged, regular extension of the BTZ black hole solution by employing nonlinear Born-Infeld electrodynamics, supplemented with the Hoffmann term and gluing different spacetimes. The role of the latter term is to divide spacetime in a natural way into two regions by a circle and eliminate the inner singularity. Thermodynamics of such a black hole is investigated by Kaluza-Klein reduction to the 1+1-dimensional dilaton gravity.Comment: 9 pages, 2 figures, final version for publication in Physics Letters

Analytic study of properties of holographic superconductors in Born-Infeld electrodynamics

In this paper, based on the Sturm-Liouville eigenvalue problem, we analytically investigate several properties of holographic s-wave superconductors in the background of a Schwarzschild-AdS spacetime in the framework of Born-Infeld electrodynamics. Based on a perturbative approach, we explicitly find the relation between the critical temperature and the charge density and also the fact that the Born-Infeld coupling parameter indeed affects the formation of scalar hair at low temperatures. Higher value of the Born-Infeld parameter results in a harder condensation to form. We further compute the critical exponent associated with the condensation near the critical temperature. The analytical results obtained are found to be in good agreement with the existing numerical results.Comment: 12 pages, LateX, To appear in JHE