Prevision of the Bearing Capacity of Superficial Foundation on Jointed Rock

The article describes the application, in Greece, of an approximate resolution of the prevision of the superficial foundation bearing capacity of a school building group on jointed granite. The method is based on the mechanics of the discontinuous media. On a sufficient number of a canvas points which is situated on the critical section under the foundation, the developing shear stresses are defined, based on the elastic theory, and they are compared with the variable -into the various directions- shear strength of the jointed rock. The resulted data conduct to the setting of boundaries of plastic zones which allow the approach of the failure form and of the sliding body. The limited load value is defined by successive approximations

Influence of relaxation on propagation, storage and retrieving of light pulses in electromagnetically induced transparency medium

By solving the self-consistent system of Maxwell and density matrix equations to the first order with respect to nonadiabaticity, we obtain an analytical solution for the probe pulse propagation. The conditions for efficient storage of light are analyzed. The necessary conditions for optical propagation distance has been obtained.Comment: 7 pages, 7 figure

Underpinning of a Tilted Building, A Case History

In the paper, the case history of underpinning of a tilted four-storey building located near Kastoria lake, Greece, is presented. Based on geotechnical investigation results, the causes of tilting and the further behaviour of the building are investigated and the underpinning system is also presented

Electromagnetically induced transparency in an inverted Y-type four-level system

The interaction of a weak probe laser with an inverted-Y type four-level atomic system driven by two additional coherent fields is investigated theoretically. Under the influence of the coherent coupling fields, the steady-state linear susceptibility of the probe laser shows that the system can have single or double electromagnetically induced transparency windows depending on the amplitude and the detuning of the coupling lasers. The corresponding index of refraction associated with the group velocity of the probe laser can be controlled at both transparency windows by the coupling fields. The propagation of the probe field can be switched from superluminal near the resonance to subluminal on resonance within the single transparency window when two coupling lasers are on resonance. This provides a potential application in quantum information processing. We propose an atomic $^{87}Rb$ system for experimental observation

Micromechanical model of rough contact between rock blocks with application to wave propagation

This is the published version. Copyright 2008 De Gruyter Open.The relationship between effective stiffness of rough contacts of rock blocks and transmission of plane waves is well known. Effective stiffness of a rough contact may be related to the force-deformation behavior of the asperity contacts and the statistical description of rock joint surface topography through micromechanical methods. In this paper, a micromechanical methodology for computing the overall rock contact effective stiffness is utilized along with the imperfectly bonded interface model to investigate how transmitted and reflected wave amplitudes are affected by the incident wave frequency, rock joint closure and the existing rock joint normal stress conditions. As a result, expressions for reflected and transmitted wave amplitudes as well as group time delay of the wave-packets are obtained and parametrically evaluated