3D seismic imaging and characterization of heterogeneous fractures

In our recent works [65,66], we demonstrate via the frameworks of linear sampling and boundary integral equations the feasibility of non-iterative, 3D seismic waveform tomography of heterogeneous fractures. This includes both (i) geometric fracture reconstruction and (ii) quantitative mapping of its shear and normal specific stiffness distributions — reflecting e.g. the fracture aperture, surface roughness, […]

Fatemeh Pourahmadian appointed Assistant Professor at the University of Colorado at Boulder

Following a 4-month postdoctoral position in at the University of Minnesota, Fatemeh Pourahmadian has joined the University of Colorado at Boulder, Department of Civil, Environmental and Architectural Engineering as tenure-track Assistant Professor in January 2017.

International Conference WAVES 2017 at the University of Minnesota, May 15−19, 2017

WAVES 2017

The 13th International Conference on Mathematical and Numerical Aspects of Wave Propagation

University of Minnesota, Twin Cities campus

May 15−19, 2017

The 13th International Conference on Mathematical and Numerical Aspects of Wave Propagation will be held at the University of Minnesota. This biannual conference series is one of the main venues for dissemination of the latest advances in theoretical and computational modeling of wave phenomena, catering to the emerging problems in science and technology.

Conference Themes: Forward and Inverse Scattering, Fast Computational Techniques, Numerical Analysis, Domain Decomposition, Analytical & Asymptotic Methods, Nonlinear Wave Phenomena, Water Waves, Guided Waves and Random Media, Medical and Seismic Imaging, Homogenization of Wave Problems, Modeling Aspects in Photonics and Phononics, Mathematical Problems in Optics.

Organizers: Bojan Guzina and Stefano Gonella

Prof. Paul Barbone vists CEGE as MTS Visiting Professor in Geomechanics

Paul Barbone, Professor of Theoretical Acoustics & Applied Mechanics at Boston University, is visiting CEGE as MTS Visiting Professor in Geomechanics Nov. 1-7, 2106.

 

Sound of a chessboard: homogenization of wave motion in periodic solids

This work [59] illustrates the pursuit of a formal two-scale homogenization approach to extract the mean wave motion in bi-periodic solids, including the effect of incipient dispersion. We show that such low-frequency expansion leads to a family of fourth-order PDEs (resembling the phenomenological models of gradient elasticity) whose coefficients derive explicitly from the microstructure.

Multiply scattered waves sense fractal microscopic structures via dispersion

In this collaborative study [62] with Ralph Sinkus and Sverre Holm, we demonstrate by experiment and theory the ability of elastic waves to sense random microstructures that are three decades smaller in size than the probing wavelength. Our analysis deploys an extension of the O’Doherty-Anstey (ODA) theory and the fact that interparticle distances in random monosized distributions may exhibit fractal character.

Why the high-frequency inverse scattering by topological sensitivity may work

In this investigation [61], we provide theoretical justification of an experimentally-observed ability [56] of the Topological Sensitivity (TS) indicator to localize near the boundary of a scatterer at high frequencies. The analysis revolves around the use of catastrophe theory and highlights the importance of source aperture in solving inverse scattering problems.

Egor Dontsov appointed Assistant Professor at the University of Houston

Following a 16-month postdoctoral appointment in the Department of Mathematics at the University of British Columbia, Egor Dontsov has joined the University of Houston, Department of Civil and Environmental Engineering as tenure-track Assistant Professor in September 2015.