Probing a polymerized black hole with the frequency shifts of photons

As is well-known, black hole plays an important role in probing the quantum effects of gravity in the strong-field regime. In this paper, we focus on a polymerized black hole and investigate the quantum effects on the redshift, blueshift and gravitational redshift of photons emitted by massive particles revolving around this black hole. With a general relativistic formalism, we obtain two elegant and concise expressions for the mass of the black hole and the quantum parameter in terms of few direct observables, and find that all the frequency shifts of photons decrease with the quantum parameter. By expanding the total frequency shift for large orbit of the emitter, low peculiar redshift, and small azimuthal angle, we find that the leading contributions to the frequency shift are originated from the kinematic shift and peculiar shift, and the quantum effects make a negligible contribution. In addition, we study the effects of the plasma on the redshift/blueshift for the first time, and conclude that the presence of plasma results in the decrease of the redshift/blueshift.Comment: 8 pages, 2 figures; published in Physical Review

Study of fire smoke movement from building integrated photovoltaic (BIPV) double skin façade (DSF) fires using helium gas

Abstract: Advanced building technologies such as building integrated photovoltaics (BIPVs) systems have been widely applied in new and existing constructions, in order to reduce energy consumption and electricity demand in buildings. Meanwhile they can cause a new critical challenge, i.e., fire safety issues. On the one hand, plume from the PV panel fires could spread into the buildings through the windows and ventilation openings. On the other hand, the risk of fire can be elevated by affecting the propagation of fire inside and outside the building. Furthermore, interfering with the smoke and venting system, firefighting operation, and electrical shock dangers. Most of the studies on the PV panels are to find the cause of failure, improving the cell efficiency, cost reduction and extracting maximum power, while there is the need to study the mechanism for smoke propagation as well. Applying BIPV on the building cause major changes in the traditional method of using structural components. These changes may include changes in the material, standard distances, gaps, and duties of elements, each of which can bring new fire safety issues.Résumé de la communication présentée lors du congrès international tenu conjointement par Canadian Society for Mechanical Engineering (CSME) et Computational Fluid Dynamics Society of Canada (CFD Canada), à l’Université de Sherbrooke (Québec), du 28 au 31 mai 2023