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- Slob, E.C. (author), Hunziker, J.W. (author), Mulder, W.A. (author) journal article 2010
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Wapenaar, C.P.A. (author), Slob, E.C. (author), Snieder, R. (author), Curtis, A. (author)In the 1990s, the method of time-reversed acoustics was developed. This method exploits the fact that the acoustic wave equation for a lossless medium is invariant for time reversal. When ultrasonic responses recorded by piezoelectric transducers are reversed in time and fed simultaneously as source signals to the transducers, they focus at the...journal article 2010
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Slob, E.C. (author), Sato, M. (author), Olhoeft, G. (author)During the past 80 years, ground-penetrating radar (GPR) has evolved from a skeptically received glacier sounder to a full multicomponent 3D volume-imaging and characterization device. The tool can be calibrated to allow for quantitative estimates of physical properties such as water content. Because of its high resolution, GPR is a valuable...journal article 2010
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Fan, Y. (author), Snieder, R. (author), Slob, E. (author), Hunziker, J.W. (author), Singer, J. (author), Sheiman, J. (author), Rosenquist, M. (author)Controlled?source electromagnetics (CSEM) has been used as a de?risking tool in the hydrocarbon exploration industry. Although there have been successful applications of CSEM, this technique is still not widely used in the industry because the limited types of hydrocarbon reservoirs CSEM can detect. In this paper, we apply the concept of...journal article 2010
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Slob, S. (author)The research investigates the possibility of using point cloud data from 3-D terrestrial laser scanning as a basis to characterise discontinuities in exposed rock massed in an automated way. Examples of discontinuities in rock are bedding planes, joints, fractures and schistocity. The characterisation of discontinuities is of importance, since...doctoral thesis 2010
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Wapenaar, C.P.A. (author), Slob, E.C. (author), Snieder, R. (author)We have analyzed the far-field approximation of the Green's function representation for seismic interferometry. By writing each of the Green's functions involved in the correlation process as a superposition of a direct wave and a scattered wave, the Green's function representation is rewritten as a superposition of four terms. When the...journal article 2010
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Slob, E.C. (author), Snieder, R. (author), Revil, A. (author)We show that the two-point cross-correlation of self-potential field recordings is equal to the electric resistivity between the two points. This holds under the condition that spatially and temporally uncorrelated noise sources exist throughout the volume. These sources should have a known amplitude spectrum and their correlated strengths...journal article 2010
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Jardani, A. (author), Revil, A. (author), Slob, E.C. (author), Söllner, W. (author)The interpretation of seismoelectrical signals is a difficult task because coseismic and seismoelectric converted signals are recorded simultaneously and the seismoelectric conversions are typically several orders of magnitude smaller than the coseismic electrical signals. The seismic and seismoelectric signals are modeled using a finite-element...journal article 2009
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Slob, E.C. (author)Interferometric techniques are now well known to retrieve data between two receivers by the cross correlation of the data recorded by these receivers. Cross-correlation methods for interferometry rely mostly on the assumption that the medium is loss free and that the sources are all around the receivers. A recently developed method introduced...journal article 2009
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- Slob, W. (author) master thesis 2009
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Jadoon, K.Z. (author), Slob, E. (author), Vanclooster, M. (author), Vereecken, H. (author), Lambot, S. (author)Precise measurement of soil hydraulic properties at field scales is one of the prerequisites to simulate subsurface flow and transport processes, which is crucial in many research and engineering areas. In our study, we numerically analyze uniqueness and stability for integrated hydrogeophysical inversion of time-lapse, off-ground ground...journal article 2008
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Missiaen, T. (author), Slob, E. (author), Donselaar, M.E. (author)In order to validate existing models of sedimentation in active sedimentary environments, detailed stratigraphic information is indispensable. Near-surface geophysical methods provide a means to acquire high-resolution images of the stratigraphic succession in the shallow subsurface. Land-based and marine methods have been tested in the...journal article 2008
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Toxopeus, G. (author), Thorbecke, J.W. (author), Wapenaar, C.P.A. (author), Petersen, S. (author), Slob, E.C. (author), Fokkema, J.T. (author)The simulation of migrated and inverted data is hampered by the high computational cost of generating 3D synthetic data, followed by processes of migration and inversion. For example, simulating the migrated seismic signature of subtle stratigraphic traps demands the expensive exercise of 3D forward modeling, followed by 3D migration of the...journal article 2008
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Lambot, S. (author), Slob, E.C. (author), Vereecken, H. (author)We propose an efficient integration path for the fast evaluation of the three?dimensional spatial?domain Green's function for electromagnetic wave propagation in layered media for the particular case of zero?offset, source?receiver proximal ground?penetrating radar (GPR) applications. The integration path is deformed in the complex plane of the...journal article 2007
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Mulder, W.A. (author), Wirianto, M. (author), Slob, E.C. (author)We modeled time-domain EM measurements of induction currents for marine and land applications with a frequency-domain code. An analysis of the computational complexity of a number of numerical methods shows that frequency-domain modeling followed by a Fourier transform is an attractive choice if a sufficiently powerful solver is available. A...journal article 2007
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Plug, W.J. (author), Slob, E. (author), Van Turnhout, J. (author), Bruining, J. (author)The relation between capillary pressure (Pc) and interfacial area has been investigated by measuring Pc and the electric permittivity at 100 kHz simultaneously as function of the water saturation, (Sw). Drainage and imbibition experiments have been conducted for sand-distilled water-gas (CO2/N2) systems. The main capillary cycles and the...journal article 2007
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Plug, W.J. (author), Slob, E.C. (author), Bruining, J. (author), Moreno Tirado, L.M. (author)We present a tool that simultaneously measures the complex permittivity and the capillary pressure characteristics for multiphase flow. The sample holder is a parallel plate capacitor. A precision component analyzer is used to measure the impedance amplitude and phase angle as a function of frequency (1 kHz to 3 MHz). The complex impedance of...journal article 2007
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Slob, E.C. (author), Wapenaar, C.P.A. (author)It is shown that the electromagnetic Green's functions of any linear medium with arbitrary heterogeneity can be obtained from the cross?correlation, or the cross?convolution, of two recordings at different receiver locations in an open system. Existing representations are known for cross?correlations where time?reversal invariance is exploited...journal article 2007
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Wapenaar, C.P.A. (author), Slob, E.C. (author), Snieder, R. (author)It has been shown by many authors that the cross correlation of two recordings of a diffuse wave field at different receivers yields the Green’s function between these receivers. Recently the theory has been extended for situations where time-reversal invariance does not hold (e.g., in attenuating media) and where source-receiver reciprocity...journal article 2006
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Lambot, S. (author), Slob, E.C. (author), Vanclooster, M. (author), Vereecken, H. (author)We propose an integrated electromagnetic-hydrodynamic inverse modeling approach for identifying field-scale unsaturated soil hydraulic properties and electric profiles from off-ground time-lapse ground-penetrating radar data. Hydrodynamic modeling based on the one-dimensional Richards' equation with homogeneous soil hydraulic parameters is used...journal article 2006