Applying FRAM to the construction of concrete frame structures

So far the FRAM has been applied to different sectors of high risk and complexity such as aviation, including air traffic control, health care, nuclear power plants, chemical and petrochemical industry, railways, maritime sector... obtaining very positive results, which have led to an improvement in safety management in them. However, its application to the construction sector has not yet been developed in depth. In the European Union, the construction sector is the sector with the highest number of accidents, so safety in construction is a priority. Structures construction is one of the most hazardous construction phases or activities. For this reason, the project "Composite Leading Indicators for the improvement of the resilience of occupational safety, in the activities of design and execution of structures" (BIA2016-79270-P) aims to improve the management and monitoring of occupational safety in these activities using novel vision of Safety II developed by the Resilience Engineering. In this way, the FRAM approach has been applied to know the work-as-done, that is, to identify the adjustments and variability of daily performance. For this purpose, observations and interviews at the place of work have been carried out. With the information collected and the help of the FRAM Model Visualiser (FMV) the functions of the FRAM model have been defined. Thus, the FRAM analysis for the construction of concrete frame structures is presented. Based on these results, leading indicators will be designed to monitor and control these activities adequately in the next phase of the project.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.We wish to thank the Spanish Ministry of Economy and Competitiveness for financing the project BIA2016-79270-P, of which this study is part. It is also important to acknowledge the Ministry of Education, Culture and Sports of the Government of Spain for it support through the predoctoral program (FPU 2016/03298)

Some not-so-common ideas about gravity

Most of the approaches to the construction of a theory of quantum gravity share some principles which do not have specific experimental support up to date. Two of these principles are relevant for our discussion: (i) the gravitational field should have a quantum description in certain regime, and (ii) any theory of gravity containing general relativity should be relational. We study in general terms the possible implications of assuming deviations from these principles, their compatibility with current experimental knowledge, and how can they affect future experiments.Comment: 12 pages (+ references). Invited talk at DICE2014, Castiglioncello, September 201

Weyl relativity: A novel approach to Weyl's ideas

In this paper we revisit the motivation and construction of a unified theory of gravity and electromagnetism, following Weyl's insights regarding the appealing potential connection between the gauge invariance of electromagnetism and the conformal invariance of the gravitational field. We highlight that changing the local symmetry group of spacetime permits to construct a theory in which these two symmetries are combined into a putative gauge symmetry but with second-order field equations and non-trivial mass scales, unlike the original higher-order construction by Weyl. We prove that the gravitational field equations are equivalent to the (trace-free) Einstein field equations, ensuring their compatibility with known tests of general relativity. As a corollary, the effective cosmological constant is rendered radiatively stable due to Weyl invariance. A novel phenomenological consequence characteristic of this construction, potentially relevant for cosmological observations, is the existence of an energy scale below which effects associated with the non-integrability of spacetime distances, and an effective mass for the electromagnetic field, appear simultaneously (as dual manifestations of the use of Weyl connections). We explain how former criticisms against Weyl's ideas lose most of their power in its present reincarnation, which we refer to as Weyl relativity, as it represents a Weyl-invariant, unified description of both the Einstein and Maxwell field equations.Comment: 34 pages, no figure

Black holes turn white fast, otherwise stay black: no half measures

Recently, various authors have proposed that the first ultraviolet effect on the gravitational collapse of massive stars to black holes is the transition between a black-hole geometry and a white-hole geometry, though their proposals are radically different in terms of their physical interpretation and characteristic time scales [1,2]. Several decades ago, it was shown by Eardley that white holes are highly unstable to the accretion of small amounts of matter, being rapidly turned into black holes [3]. Studying the crossing of null shells on geometries describing the black-hole to white-hole transition, we obtain the conditions for the instability to develop in terms of the parameters of these geometries. We conclude that transitions with long characteristic time scales are pathologically unstable: occasional perturbations away from the perfect vacuum around these compact objects, even if being imperceptibly small, suffocate the white hole explosion. On the other hand, geometries with short characteristic time scales are shown to be robust against perturbations, so that the corresponding processes could take place in real astrophysical scenarios. This motivates a conjecture about the transition amplitudes of different decay channels for black holes in a suitable ultraviolet completion of general relativity.Comment: 24 pages, 3 figures. V2: Minor changes and updated references. Matches the published versio

Where does the physics of extreme gravitational collapse reside?

The gravitational collapse of massive stars serves to manifest the most severe deviations of general relativity with respect to Newtonian gravity: the formation of horizons and spacetime singularities. Both features have proven to be catalysts of deep physical developments, especially when combined with the principles of quantum mechanics. Nonetheless, it is seldom remarked that it is hardly possible to combine all these developments into a unified theoretical model, while maintaining reasonable prospects for the independent experimental corroboration of its different parts. In this paper we review the current theoretical understanding of the physics of gravitational collapse in order to highlight this tension, stating the position that the standard view on evaporating black holes stands for. This serves as the motivation for the discussion of a recent proposal that offers the opposite perspective, represented by a set of geometries that regularize the classical singular behavior and present modifications of the near-horizon Schwarzschild geometry as the result of the propagation of non-perturbative ultraviolet effects originated in regions of high curvature. We present an extensive exploration of the necessary steps on the explicit construction of these geometries, and discuss how this proposal could change our present understanding of astrophysical black holes and even offer the possibility of detecting genuine ultraviolet effects on future gravitational wave experiments.Comment: 43 pages, 1 figure. Review article with new results on the black to white hole transition. Prepared for the special issue "Open Questions in Black Hole Physics" edited by Gonzalo J. Olm

Influence of Adaptive Comfort Models in Execution Cost Improvements for Housing Thermal Environment in Concepción, Chile

Most of the operational energy needed by the housing sector is used to compensate energy losses or thermal gains through the building’s envelope. As a result, any improvement in the thermal behavior will provide important opportunities to reduce energy consumption. This research analyzes improvements in the thermal envelope in social housing in the Greater Concepción area in Chile using adaptive thermal comfort models and thermal insulation investments. The objective set out is to evaluate the economic reduction of thermal envelope improvement costs for dwellings, which entails using the adaptive thermal comfort model obtained through monitoring and the surveys applied to the users of social housing in Concepción (CAS), against the international adaptive thermal comfort models established by the EN 15251:2007 and ASHRAE 55-2017 standards. Finally, it is concluded that, on having applied the social housing adaptive thermal comfort model (CAS), execution costs are reduced by between 28.8% and 58.2%, reaching a time of comfort in free oscillation similar to that obtained from applying the models of the EN 15251:2007 (74.2%) and ASHRAE 55-2017 standards (59.9%)CONICYT FONDECYT 3160806VI PPIT-U