The problem of expressing a general 3-D magnetotelluric (MT) impedance tensor in the form of a 2-D tensor that has been distorted in some way is addressed first in terms of a general theorem. This theorem shows that when the real and quadrature parts of a tensor are analyzed separately as distinct matrices, all that is necessary to make a matrix with 2-D characteristics from one with 3-D charac...

NATURE | VOL 412 | 9 AUGUST 2001 | www.nature.com 635 8. McKenzie, D. Finite deformation during ̄uid ̄ow. Geophys. J. R. Astron. Soc. 58, 689±715 (1979). 9. Ribe, N. M. Seismic anisotropy and mantle ̄ow. J. Geophys. Res. 94, 4213±4223 (1989). 10. Gripp, A. E. & Gordon, R. G. Current plate velocities relative to the hotspots incorporating the NUVEL-1 global plate motion model. Geophys. Res. Lett. 1...

‎The object of the present paper is to study spacetimes admitting‎ ‎quasi-conformal curvature tensor‎. ‎At first we prove that a quasi-conformally flat spacetime is Einstein‎ ‎and hence it is of constant curvature and the energy momentum tensor of such a spacetime satisfying‎ ‎Einstein's field equation with cosmological constant is covariant constant‎. ‎Next‎, ‎we prove that if the perfect flui...

in this study, a novel variable impedance control for a lower-limb rehabilitation robotic system using voltage control strategy is presented. the majority of existing control approaches are based on control torque strategy, which require the knowledge of robot dynamics as well as dynamic of patients. this requires the controller to overcome complex problems such as uncertainties and nonlinearit...

Spatially homogeneous Bianchi type-II, VIII and IX anisotropic, as well as isotropic cosmological models can be obtained in a scalar tensor theory of gravitation proposed by Saez and Ballester (1986) when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. All the models obtained and presented here are expanding, non-rotating and accelerating...

a method for deformation computation based on strain tensor elements, as an alternative to the usual way of application of gradient of displacement vector, is proposed. the method computes directly the strain tensor elements from the computed/observed changes in distances and angles between the stations of a geodetic network in two epochs of observations. displacement vector which is determined...

• Novel, accurate computational solutions to a series of polarizability tensor object characterisations. Application the Boundary Element Python Package (Bempp) and grid adaption characterization small objects. Benchmark computations interest electrical impedance tomography practitioners software developers. The characterisation low conducting inclusions in an otherwise uniform background from ...

Background The use of a medical simulator should enhance the goals of minimally invasive surgery: patient safety, cosmesis, shortening the length of hospital admissions, and reducing cost. Using an innovative approach to the handling of ultrasound images in virtual reality simulation, this article describes a process that employs a hybrid model of deformable models that can be applied in the te...