Shake Table Test and Seismic Performance Evaluation of Bracing Members

in Proceedings of the 13th World Conference on Earthquake Engineering (2004)

Shakespeare à l'école

Speech (2008)

Shakespeare et Hamlet sur la toile

Textual, factual or bibliographical database (2003)

A shallow geothermal experiment in a sandy aquifer monitored using electric resistivity tomography

in Geophysics (2012), 77(1), 11-21

Groundwater resources are increasingly used around the world for geothermal exploitation systems. To monitor such systems and to estimate their governing parameters, we rely mainly on borehole ... [more ▼]

Groundwater resources are increasingly used around the world for geothermal exploitation systems. To monitor such systems and to estimate their governing parameters, we rely mainly on borehole observations of the temperature field at a few locations. Bulk electrical resistivity variations can bring important information on temperature changes in aquifers. In this paper, we demonstrate the ability of surface electrical resistivity tomography to monitor spatially temperature variations in a sandy aquifer during a thermal injection test. Heated water (48°C) was injected for 70 hours at the rate of 87 l/h in a 10.5°C aquifer. Temperature changes derived from time-lapse electrical images are in agreement with laboratory water electrical conductivity-temperature measurements. In parallel, a coupled hydrogeological saturated flow and heat transport model was calibrated on geophysical data for the conceptual model, and on hydrogeological and temperature data for the parameters. The resistivity images showed an upper flow of heated water along the well above the injection screens and lead to a new conceptualization of the hydrogeological source term. The comparison between the temperature models derived from resistivity images and from the simulations is satisfactory. Quantitatively, resistivity changes allowed estimating temperature changes within the aquifer, and qualitatively, the heated plume evolution was successfully monitored. This work demonstrates the ability of electrical resistivity tomography to study heat and storage experiments in shallow aquifers. These results could potentially lead to a number of practical applications, such as the monitoring or the design of shallow geothermal systems. [less ▲]

Shallow heat injection and storage experiment monitored with electrical resistivity tomography and simulated with heat transport model

Poster (2011, December 06)

Groundwater resources are increasingly used around the world as geothermal systems. Understanding physical processes and quantification of parameters determining heat transport in porous media is ... [more ▼]

Groundwater resources are increasingly used around the world as geothermal systems. Understanding physical processes and quantification of parameters determining heat transport in porous media is therefore important. To monitor the geothermal behavior of groundwater systems and to estimate the governing parameters, we rely mainly on borehole observations of the temperature field at a few locations (temperature logs or thermal response test). In analogy to research in hydrogeophysics, geophysical methods may be useful in order to yield additional information for thermal properties estimation with greater coverage than conventional wells. We report a heat transport study during a shallow heat injection and storage field test. Heated water (about 50°C) was injected for 6 days at the rate of 80 l/h in 10.5°C aquifer. Since bulk electrical resistivity variations can bring important information on temperature changes in aquifers (water electrical conductivity increases about 2%/°C around 25°C), we monitored the test with surface electrical resistivity tomography and demonstrate its ability to monitor spatially temperature variations. Time-lapse electrical image clearly show the decrease and then the increase in bulk electrical resistivity of the plume of heated water, during respectively the injection and the storage phase. This information enabled to calibrate the conceptual flow and heat model used to simulate the test (using SEAWAT). Inverted resistivity values are validated with borehole electromagnetic measurements (EM39) and are in agreement with the temperature logs used to calibrate the parameters of the thermo-hydrogeological model. This field work demonstrates that surface electrical resistivity tomography can monitor heat and storage experiments in shallow aquifers. These results could potentially lead to a number of practical applications, such as the monitoring or the design of shallow geothermal systems. Moreover, sensitivity analyses and collinear diagnostic were used to assess the pertinence of the flow and heat model parameters. The most sensitive parameter is the conductivity of the solid followed by the porosity, heat capacity of the solid and the longitudinal dispersivity. This indicates the predominance of conductive transport during the storage phase over the convective transport during the injection phase. These values rely only on temperature logs and more parameters could be derived or more robust values could be achieved with the use of geophysical data in a coupled inversion scheme. [less ▲]

Shape and mesh optimization using geometric modeling methods

in AIAA/ASME/ASCE/AHS/ASC 31st Structures, Structural Dynamics and Materials Conference : April 2-4, 1990 (1990)

Shape Induced Symmetry in Self-Assembled Mesocrystals of Iron Oxide Nanocubes

in Nano Letters (2011), 11(4), 1651-1656

Grazing incidence small-angle scattering,and electron microscopy have been used to show for the first time that nonspherical nanoparticles can assemble into highly ordered body-centered tetragonal ... [more ▼]

Grazing incidence small-angle scattering,and electron microscopy have been used to show for the first time that nonspherical nanoparticles can assemble into highly ordered body-centered tetragonal mesocrystals. Energy models accounting for the directionality and magnitude of the van der Waals and dipolar interactions as a function of the degree of truncation of the nanocubes illustrated the importance of the directional dipolar forces for the formation of the initial nanocube clusters and the dominance of the van der Waals multibody interactions in the dense packed arrays. [less ▲]

Shape Optimal Design - An Approach Matching C.A.D. and Optimization Concepts

in Gero, John S. (Ed.) Optimization in Computer Aided Design: proceedings of the IFIP WG 5.2 Working Conference on Optimization in Computer-Aided Design, Lyon, France, 24-26 October, 1983 (1985)

Shape optimal-design using B-splines

in Computer Methods in Applied Mechanics & Engineering (1984), 44(3), 247-267

Shape optimal design of an elastic structure is formulated using a design element technique. It is shown that Bezier and B-spline curves, typical of the CAD philosophy, are well suited to the definition ... [more ▼]

Shape optimal design of an elastic structure is formulated using a design element technique. It is shown that Bezier and B-spline curves, typical of the CAD philosophy, are well suited to the definition of design elements. Complex geometries can be described in a very compact way by a small set of design variables and a few design elements. Because of the B-splines flexibility, it is no longer necessary to piece design elements together in order to agree with the shape complexity, nor to restrict the shape variations. Moreover, the additional optimization constraints that are most often needed to avoid unrealistic designs when the shape variables are the nodal coordinates of a finite element mesh, are automatically taken into account in the new formulation. An analytical derivation of the sensitivity analysis will be established, giving rise to numerical efficiency. It will be seen that the resulting optimization problem does not involve highly nonlinear functions with respect to the shape variables, so that simple mathematical programming algorithms can be applied to solve it. Some numerical examples are offered to demonstrate the power and generality of the new approach presented in this paper. [less ▲]

Shape processing and analysis using the calypter

in Journal of Microscopy (1994), 175(3), 214-221