We study numerically the collapse of massless scalar elds in two-dimensional dilaton gravity, both classically and semiclassically. At the classical level, we nd that the black hole mass scales at threshold like M bh / jp ? p j , where ' 0:53. At the semiclassical level, we nd that in general M bh approaches a non-zero constant as p ! p. Thus, quantum eeects produce a mass gap not present class...

This paper presents a new interpretation of the geometry of Triassic alignment of J. Sidi Mahdi –J. Zitoun in Medjerda Valley Plain (Northern Tunisia) based on detailed analysis of gravity and seismic reflection data. The main results of gravity analysis do not show a distinguish gravity anomaly over Triassic evaporites bodies. The positive gravity anomaly seems to be related to the entire stru...

A bstract In this paper, we investigate the internal structure of a charged hairy black hole solution in non-linear massive gravity. We first consider impact various configurations gravity on condensate operator and then probe interior dynamics. Like standard holographic superconductor system, just below critical temperature, evolves through several distinct epochs, including collapse Einstein-...

The progressive collapse of the spatial grid structure is focus and difficulty current research. stability problem single-layer latticed shell more prominent due to its low redundancy. In this paper, dynamic nonlinear analysis Zhoukoudian large-span carried out study process by finite element software ABAQUS. results show that eventually under 7 times gravity load. mid-span zone on left side we...

We present two-dimensional simulations of finite, self-gravitating gaseous sheets. Unlike the case of infinite sheets, such configurations do not constitute equilibrium states but instead are subject to global collapse unless countered by pressure forces or rotation. The initial effect of finite geometry is to promote concentrations of material at the edges of the sheet. If the sheet is not per...

We report on an experimental and numerical study of the collapse under gravity of a rectangular well in a quasi-two-dimensional granular bed. For comparison, we also perform experiments on the collapse of a single vertical step. Experiments are conducted in a vertical Hele-Shaw cell, which allows the flow to be recorded from the side using high-speed video. If the rectangular well is sufficient...

Load carrying capacity of flat double-layer space structures majorly depends on the structures' imperfections. Imperfections in initial curvature, length, and residual stress of members are all innately random and can affect the load-bearing capacity of the members and consequently that of the structure. The double-layer space trusses are susceptible to progressive collapse due to sudden buckli...

We suggest that the Orion A cloud is gravitationally collapsing on large scales, and is producing the Orion Nebula Cluster due to the focusing effects of gravity acting within a finite cloud geometry. In support of this suggestion, we show how an elliptical rotating sheet of gas with a modest density gradient along the major axis can collapse to produce a structure qualitatively resembling Orio...