@article {Garcia2014a,
	title = {{Constraints on a shallow offshore gas environment determined by a multidisciplinary geophysical approach: The Malin Sea, NW Ireland}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {15},
	number = {4},
	year = {2014},
	pages = {867{\textendash}885},
	issn = {15252027},
	doi = {10.1002/2013GC005108},
	url = {http://doi.wiley.com/10.1002/2013GC005108},
	author = {Garcia, Xavier and Monteys, Xavier and Evans, Rob L. and Szpak, Michal}
}
@booklet {Ranero2014,
	title = {{The Western Mediterranean Pairs of Basin and Arc Systems}},
	year = {2014},
	month = {feb},
	publisher = {Sociedad Geol{\'o}gica de Espa{\~n}a},
	abstract = {Ranero, C{\'e}sar R. ... et. al.{\textendash} VIII Congreso Geol{\'o}gico de Espa{\~n}a, 2012, Oviedo},
	isbn = {http://hdl.handle.net/10261/92021},
	url = {http://digital.csic.es/handle/10261/92021},
	author = {Ranero, Cesar R. and Gr{\'a}cia, Eul{\`a}lia and Sallares, Valenti and Garcia, Xavier and Gallart Muset, Josep and Bartolom{\'e}, Rafael and Lo Iacono, Claudio and Martinez-Loriente, S. and Moreno, Ximena and Prada, Manel and Perea, Hector and Zitellini, N.}
}
@article {NEUKIRCH2013,
	title = {{NONSTATIONARY TIME SERIES CONVOLUTION: ON THE RELATION BETWEEN THE HILBERT{\textendash}HUANG AND FOURIER TRANSFORM}},
	journal = {Advances in Adaptive Data Analysis},
	volume = {05},
	number = {01},
	year = {2013},
	month = {jan},
	pages = {1350004},
	publisher = {World Scientific Publishing Company},
	abstract = {The Hilbert{\textendash}Huang Transform (HHT) decomposes time series into intrinsic mode functions (IMF) in time-frequency domain. We show that time slices of IMFs equal time slices of Fourier series, where the instantaneous parameters of the IMF define the parameters amplitude and phase of the Fourier series. This leads to the formulation of the theorem that nonstationary convolution of an IMF with a general time domain response function translates into a multiplication of the IMF with the respective spectral domain response function which is explicitly permitted to vary over time. We conclude and show on a real world application that a de-trended signal{\textquoteright}s IMFs can be convolved independently and then be used for further time-frequency analysis. Finally, a discussion is opened on parallels in HHT and the Fourier transform with respect to the time-frequency domain.},
	keywords = {convolution, Fourier transform, Hilbert{\textendash}Huang transform, nonstationary, Time series},
	issn = {1793-5369},
	doi = {10.1142/S1793536913500040},
	url = {http://www.worldscientific.com/doi/abs/10.1142/S1793536913500040},
	author = {NEUKIRCH, MAIK and Garcia, Xavier}
}
@conference {Gutierrez2013,
	title = {{Statistical model of a signal of Raman spectroscopy: Detection}},
	booktitle = {Symposium of Signals, Images and Artificial Vision - 2013: STSIVA - 2013},
	year = {2013},
	month = {sep},
	pages = {1{\textendash}5},
	publisher = {IEEE},
	organization = {IEEE},
	abstract = {Raman spectroscopy (RS) is a technique to find the spectral fingerprint of a material under study. To reach the spectrum, it is necessary to pass the acquired signal at the spectrometer by a bank of filters known as Raman signal{\textquoteright}s preprocessing system, which should eliminate all noise components accompanying the signal. The behavior of these noise components, and even the signal itself, are information that can be useful in order to optimize the system and to study the signal itself. This paper proposes a statistical model of Raman signal as the pre-processing system receives it, the signal{\textquoteright}s noise components and their statistical behavior, including its mathematical representation are presented. Additionally, it shows the results of the implementation of the simulation model leaving the door open for the validation, on which work is being done. The implementation of this model may be useful as an input signal for the optimization of the filter banks, since there are not always sufficient Raman signals for detailed study and development of filters for a specific signal under study. The model could also be used as a base for the study for systems using Raman spectroscopy to recognize substances. {\textcopyright} 2013 IEEE.},
	keywords = {pre-processing system of the Raman signal, Raman spectrometry, spectral fingerprint, statistical model},
	isbn = {978-1-4799-1121-9},
	doi = {10.1109/STSIVA.2013.6644935},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84891057081\&partnerID=tZOtx3y1},
	author = {Gutierrez, Carlos A. and Garcia, Xavier and Zurek, Eduardo E. and Salazar, Augusto}
}
@conference {Nagel2012a,
	title = {{Hydraulic fracturing optimization for unconventional reservoirs - The critical role of the mechanical properties of the natural fracture network}},
	booktitle = {Society of Petroleum Engineers - SPE Canadian Unconventional Resources Conference 2012, CURC 2012},
	volume = {1},
	year = {2012},
	pages = {227{\textendash}237},
	abstract = {The success of many shale plays depends on the optimal stimulation of natural fractures, and the characterization of the natural fracture systems is a key issue often leading to the construction of a discrete fracture network (DFN). The DFN chiefly consists of fracture spacing, fracture dip, and dip direction from numerous sources, and, in some cases, is matched to well test data allowing for the determination of hydraulic properties. However, a commonly missing component of natural fracture characterization, and the component most important to evaluating the coupled hydro-mechanical behavior of the fractures during a hydraulic fracture stimulation, is the evaluation of the mechanical behavior of the fractures. The important mechanical parameters of the fractures include: a) elastic properties such as shear and normal stiffness, which relate changes in pore pressure to changes in aperture; b) strength parameters such as cohesion and friction angle, which define when a fracture may shear and open; c) dilational properties, which relate fracture opening to shear slippage; d) fracture toughness, which determines the pressure required to extend a fracture; and e) initial aperture. In this paper, using a new, state-of-the-art, fully-coupled, 3D distinct element hydraulic fracturing simulator, mechanical fracture parameters were evaluated in a parametric study in order to determine their impact on the effectiveness of hydraulic fracture stimulations. Copyright 2012, Society of Petroleum Engineers.},
	isbn = {9781622764884},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84875645702\&partnerID=tZOtx3y1},
	author = {Nagel, Neal B. and Garcia, Xavier and Lee, Byungtark and Sanchez-Nagel, Marisela}
}
@conference {Nagel2012,
	title = {{Understanding "SRV": A numerical investigation of "wet" vs. "dry" microseismicity during hydraulic fracturing}},
	booktitle = {Proceedings - SPE Annual Technical Conference and Exhibition},
	volume = {4},
	year = {2012},
	pages = {3375{\textendash}3386},
	abstract = {Effective monitoring of hydraulic fracturing stimulations is critical to their optimization, and the evaluation of field microseismic data is now commonly used in many of the active shale plays for this purpose. The concept of Stimulated Reservoir Volume (SRV), for example, is a common technique wherein the extent of the microseismic data is used to represent the size of the fluid drainage area for a fracture or well. A principal challenge with the interpretation of microseismic data - and its use to determine drainage area or some other metric for the success of the stimulation - is the understanding of the actual cause of the microseismicity itself. Basic geomechanics principles show that rock failure - the cause of microseismicity - is a result of changes in the in-situ effective stresses relative to a given rock strength. Effective stress - which is the stress acting on the rock matrix - may change either through a change in pore pressure (leading to {\textquoteright}wet{\textquoteright} microseismicity) or through a change in the total stress (leading to {\textquoteright}dry{\textquoteright} microseismicity). Dry microseismicity may occur well beyond the pressure field and be hydraulically disconnected from the wellbore. In this paper, we present the results of a numerical study of hydraulic fracturing-induced microseismicity using a discrete element code, where the mechanical behavior of the natural fractures is modeled explicitly, which allows for the quantitative evaluation of {\textquoteright}wet{\textquoteright} versus {\textquoteright}dry{\textquoteright} microseismicity. Copyright 2012, Society of Petroleum Engineers.},
	isbn = {9781622764150},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84874038119\&partnerID=tZOtx3y1},
	author = {Nagel, Neal B. and Garcia, Xavier and Nagel, Marisela Sanchez and Lee, Byungtark}
}
@article {Santos2011,
	title = {{Compression and shear-wave velocities in discrete particle simulations of quartz granular packings: Improved Hertz-Mindlin contact model}},
	journal = {GEOPHYSICS},
	volume = {76},
	number = {5},
	year = {2011},
	month = {sep},
	pages = {E165{\textendash}E174},
	abstract = {The Hertz-Mindlin (HM) contact model has been a cornerstone for the development of several effective medium theories (EMTs) aimed at describing the mesoscopic and macroscopic mechanical behavior of granular materials like unconsolidated sands. In addition, this model is at the core of most of the discrete particle method designs used to numerically solve for the responses of these heterogeneous materials to external perturbations, like acoustic and stress-strain experiments. However, this model has shown shortcomings in the description of the shear response characterization of granular materials, partly due to the non-affine motions experienced by the grains. We have developed a correction of the model based on a detailed calibration of our acoustic numerical results with previous empirical data. Using a microscopic approach to the grain-grain contact surfaces, the nature of the corrections found appear to be related to the shear resistant asperities and the smaller scale of the grain-grain contact areas compared to the total area assumed by the HM model. An improved HM model characterized by a tangential stiffness weakening is based on these surface corrections. Using this observation an enhanced EMT theory emerges based not only on the tangential stiffness modification but also on the velocity-pressure dependence obtained during the calibration of our numerical model. {\textcopyright} 2011 Society of Exploration Geophysicists.},
	keywords = {3D, Compression wave (P-wave), Rock physics, Shear-wave (S-wave), Wave propagation},
	issn = {0016-8033},
	doi = {10.1190/geo2010-0376.1},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84857461284\&partnerID=tZOtx3y1},
	author = {Santos, Carlos and Urdaneta, Vanessa and Garcia, Xavier and Medina, Ernesto}
}
@conference {Nagel2011,
	title = {{Discrete element hydraulic fracture modeling - Evaluating changes in natural fracture aperture and transmissivity}},
	booktitle = {Society of Petroleum Engineers - Canadian Unconventional Resources Conference 2011, CURC 2011},
	volume = {2},
	year = {2011},
	pages = {1350{\textendash}1363},
	abstract = {Previous works have presented the results of successful simulations of fluid injection into naturally fractured shale using a Discrete Element Model (DEM). The simulations included coupled fluid flow-deformation analysis, failure type and extent calculations, as well as a series of parametric analyses. The parameters investigated included: 1) injection rate and its effect on the overall fracturing results, and 2) fluid viscosity, which had a significant influence on the ratio of tensile (mode 1) failure versus shear failure. With the huge growth in the stimulation of naturally fractured formations such as fractured shales, it is clear that the industry needs new hydraulic fracturing simulation tools beyond the limits imposed by pseudo3D fracturing models. DEMs, in which both matrix block behavior and fracture behavior are explicitly modeled, offer one option for the specific modeling of hydraulic fracture creation and growth in a naturally fractured formation without, for example, the assumption of bi-planar fracture growth. In this paper, we extend the previous works to quantify, for fractured shale gas plays, the effect of stress orientation, fluid viscosity, and rock mechanical properties in terms of changes in fracture aperture and transmissivity. Changes in fracture transmissivity directly correlate with improvements in well productivity - the primary goal of the stimulation. The results of the study provide a means to improve shale completions by understanding the effects of the DFN orientation relative to the stress field, fluid viscosity, and rock mechanical properties on changes in fracture aperture, fracture transmissivity, and formation effective permeability, which directly relate to well productivity. Copyright 2011, Society of Petroleum Engineers.},
	isbn = {9781618394217},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84860594665\&partnerID=tZOtx3y1},
	author = {Nagel, Neal and Damjanac, Branko and Garcia, Xavier and Sanchez-Nagel, Marisela}
}
@article {Evans2011,
	title = {{Electrical lithosphere beneath the Kaapvaal craton, southern Africa}},
	journal = {Journal of Geophysical Research},
	volume = {116},
	number = {B4},
	year = {2011},
	month = {apr},
	pages = {B04105},
	abstract = {A regional-scale magnetotelluric (MT) experiment across the southern African Kaapvaal craton and surrounding terranes, called the Southern African Magnetotelluric Experiment (SAMTEX), has revealed complex structure in the lithospheric mantle. Large variations in maximum resistivity at depths to 200-250 km relate directly to age and tectonic provenance of surface structures. Within the central portions of the Kaapvaal craton are regions of resistive lithosphere about 230 km thick, in agreement with estimates from xenolith thermobarometry and seismic surface wave tomography, but thinner than inferred from seismic body wave tomography. The MT data are unable to discriminate between a completely dry or slightly "damp" (a few hundred parts per million of water) structure within the transitional region at the base of the lithosphere. However, the structure of the uppermost \~{}150 km of lithosphere is consistent with enhanced, but still low, conductivities reported for hydrous olivine and orthopyroxene at levels of water reported for Kaapvaal xenoliths. The electrical lithosphere around the Kimberley and Premier diamond mines is thinner than the maximum craton thickness found between Kimberley and Johannesburg/Pretoria. The mantle beneath the Bushveld Complex is highly conducting at depths around 60 km. Possible explanations for these high conductivities include graphite or sulphide and/or iron metals associated with the Bushveld magmatic event. We suggest that one of these conductive phases (most likely melt-related sulphides) could electrically connect iron-rich garnets in a garnet-rich eclogitic composition associated with a relict subduction slab. Copyright 2011 by the American Geophysical Union.},
	issn = {0148-0227},
	doi = {10.1029/2010JB007883},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79955426798\&partnerID=tZOtx3y1},
	author = {Evans, Rob L. and Jones, Alan G. and Garcia, Xavier and Muller, Mark and Hamilton, Mark and Evans, Shane and Fourie, C. J. S. and Spratt, Jessica and Webb, Susan and Jelsma, Hielke and Hutchins, Dave}
}
@article {Garcia2011,
	title = {{Tricyclic Antidepressants-loaded Biodegradable PLGA Nanoparticles: In Vitro Characterization and In Vivo Analgesic and Anti-Allodynic Effect}},
	journal = {Current Nanoscience},
	volume = {7},
	number = {3},
	year = {2011},
	month = {jun},
	pages = {345{\textendash}353},
	abstract = {Tricyclic antidepressants (TCAs) have potent local pain blockade properties that could be of interest in relieving chronic pain states as neuropathic pain. The aim of this work was to reach a persistent control of nociceptive and neuropathic pain by means of an in- jectable controlled release system using lower than usual doses of TCAs. To address this issue, amitriptyline, doxepin and imipramine were encapsulated with poly (lactic-co-glycolic) acid (PLGA) as polymer. Nanoparticles were characterized. The in vitro drug release profile and mechanism was evaluated, and the in vivo analgesic and anti-allodynic activity in front of heat-induced nociceptive pain and sciatic nerve chronic constriction injury, respectively, was tested. The mean{\textpm}SD particle size and drug loadings (\%) of the nanoparticles obtained were 420{\textpm}13, 480{\textpm}73 and 373{\textpm}25nm, and 40.46{\textpm}4.11, 31.09{\textpm}3.02 and 32.20{\textpm}3.20\% for amitriptyline, doxepin and imi- pramine, respectively. According to the Korsmeyer-Peppas model, the release mechanism of doxepin was diffusion controlled, while a combination of Fickian diffusion and polymer relaxation/erosion of the PLGA matrix was involved for amitriptyline and imipramine. Af- ter local infiltration of nanoparticles in rats, the antinociceptive and anti-allodynic activity of the encapsulated drugs were long-lasting and higher than that observed from the solutions. Amitriptyline elicited the lower analgesic effect. Doxepin showed the most outstanding results and its encapsulation led to a 62\% and 229\% increase in antinociceptive and anti-allodynic activity, respectively. So, this drug could be considered as a therapeutical alternative in pain relieving treatments.{\textcopyright} 2011 Bentham Science Publishers Ltd.},
	keywords = {Anti-allodynia, Antinociception, In vitro release, Korsmeyer-peppas, Plga nanoparticles, Tricyclic antidepressants},
	issn = {15734137},
	doi = {10.2174/157341311795542336},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79956288549\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Escribano, Elvira and Colom, Helena and Domenech, Josep and Queralt, Josep}
}
@article {Garcia2011a,
	title = {{A two-phase adaptive finite element method for solid-fluid coupling in complex geometries}},
	journal = {International Journal for Numerical Methods in Fluids},
	volume = {66},
	number = {1},
	year = {2011},
	month = {may},
	pages = {82{\textendash}96},
	abstract = {In this paper we present a method to solve the Navier-Stokes equations in complex geometries, such as porous sands, using a finite-element solver but without the complexity of meshing the porous space. The method is based on treating the solid boundaries as a second fluid and solving a set of equations similar to those used for multi-fluid flow. When combined with anisotropic mesh adaptivity, it is possible to resolve complex geometries starting with an arbitrary coarse mesh. The approach is validated by comparing simulation results with available data in three test cases. In the first we simulate the flow past a cylinder. The second test case compares the pressure drop in flow through random packs of spheres with the Ergun equation. In the last case simulation results are compared with experimental data on the flow past a simplified vehicle model (Ahmed body) at high Reynolds number using large-eddy simulation (LES). Results are in good agreement with all three reference models. {\textcopyright} 2010 John Wiley \& Sons, Ltd..},
	keywords = {Anisotropic mesh adaptivity, Ergun equation, Flow past a cylinder, Flow past sphere packs, Flow past the Ahmed body, Two-fluid approach},
	issn = {02712091},
	doi = {10.1002/fld.2249},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79953156921\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Pavlidis, Dimitrios and Gorman, Gerard J. and Gomes, Jefferson L. M. A. and Piggott, Matthew D. and Aristodemou, Elsa and Mindel, Julian and Latham, John-Paul and Pain, Christopher C. and ApSimon, Helen}
}
@article {Garcia2010a,
	title = {{Analgesic and antiallodynic effects of antidepressants after infiltration into the rat.}},
	journal = {Pharmacology},
	volume = {86},
	number = {4},
	year = {2010},
	month = {jan},
	pages = {216{\textendash}23},
	abstract = {Tricyclic antidepressants (TCA) have potent local anesthetic properties and may produce a long-lasting pain blockade that could be of interest in relieving chronic pain states such as neuropathic pain, but there are only few data comparing their dose-response curves of analgesic activity under the same experimental conditions. This study examines the time course of pain-relieving properties of 7 TCA in heat-induced paw withdrawal after subcutaneous administration. Mixed inhibitors of norepinephrine and serotonin uptake (amitriptyline, nortriptyline, imipramine, desipramine, doxepin) and selective inhibitors of serotonin uptake (fluoxetine and fluvoxamine) were assayed. The TCA with the longest analgesic activity were selected to test its antiallodynic effect in the neuropathic pain model of chronic sciatic nerve constriction injury. Bupivacaine was used as a reference drug in both experiments. A dose versus time of maximal analgesic effect curve was constructed for each drug. The longest analgesic effect was obtained for doxepin and imipramine. Although low doses of amitriptyline showed the same activity than doxepin, higher doses failed to reach the same effect. Selective inhibitors of serotonin showed no action at all doses tested. In the chronic sciatic nerve constriction injury model, doxepin and, to a smaller degree, amitriptyline and imipramine protected from allodynia; bupivacaine was ineffective. The antiallodynic effect always lasted less long than the analgesic effect. These observations provide support for the potential use of TCA as durable analgesics. Doxepin overall showed the most outstanding results in pain relief.},
	keywords = {Adrenergic Uptake Inhibitors, Adrenergic Uptake Inhibitors: administration \& dos, Adrenergic Uptake Inhibitors: pharmacology, Analgesics, Analgesics: administration \& dosage, Analgesics: pharmacology, Anesthetics, Animal, Animals, Antidepressive Agents, Bupivacaine, Bupivacaine: pharmacology, Disease Models, Dose-Response Relationship, Drug, Hyperalgesia, Hyperalgesia: drug therapy, Local, Local: pharmacology, Male, Pain, Pain: drug therapy, Rats, Sciatic Neuropathy, Sciatic Neuropathy: drug therapy, Serotonin Uptake Inhibitors, Serotonin Uptake Inhibitors: administration \& dosa, Serotonin Uptake Inhibitors: pharmacology, Sprague-Dawley, Time Factors, Tricyclic, Tricyclic: administration \&, Tricyclic: pharmacology},
	issn = {1423-0313},
	doi = {10.1159/000319747},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77956380582\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and del Valle, Jaume and Escribano, Elvira and Domenech, Josep and Queralt, Josep}
}
@article {Garcia2010,
	title = {{In vitro characterization and in vivo analgesic and anti-allodynic activity of PLGA-bupivacaine nanoparticles}},
	journal = {Journal of Nanoparticle Research},
	volume = {13},
	number = {5},
	year = {2010},
	month = {jun},
	pages = {2213{\textendash}2223},
	abstract = {An injectable controlled release system containing local anesthetics able to provide longlasting analgesia in nociceptive and neuropathic pain could have a marked impact in pain management. In order to address this issue, bupivacaine, a widely used local anesthetic, has been nanoencapsulated using poly(lactic-co-glycolic acid) from an oil-in-water emulsion by the solvent evaporation technique. Nanoparticles were evaluated in vitro studying their drug release mechanism by fitting different model equations, and in vivo by testing its analgesic and anti-allodynic activity in front of heat-induced nociceptive pain and sciatic nerve chronic constriction injury in rats, respectively. The particle size of the PLGA nanoparticles obtained was of 453 {\textpm} 29 nm, the encapsulation efficiency, drug loading, and burst effect at 30 min were 82.10 {\textpm} 0.001, 45.06 {\textpm} 0.001, and 4.6 {\textpm} 0.6\%, respectively. A prolonged release of the drug in comparison to bupivacaine solution was seen. The mean dissolution time (MDT) obtained for nanoparticles was relatively long (9.44 {\textpm} 0.56 h) proving the sustained release process, while the dissolution efficiency (DE) (84.10 {\textpm} 1.01\%) was similar to the maximum percentage of drug released. Korsmeyer- Peppas was the best model that fitted our release data.A non-Fickian mechanism was concluded to be involved in the release of bupivacaine from the nanoparticles, taking into account the value of the diffusional exponent obtained (n = 0.95). After local infiltration in the rat, the antinociceptive and anti-allodynic activity of the nanoencapsulated bupivacaine was longer lasting than that of bupivacaine solution. An increase in the values of the area under the curve (AUC) of the antinociceptive and anti-allodynic effect versus time of 67 and 36\%, respectively, was observed when the drug was encapsulated. {\textcopyright} Springer Science+Business Media B.V. 2010.},
	keywords = {Antiallodynia, Antinociception, Bupivacaine, In vitro release, Korsmeyer-peppas, Modeling and simulation, Nanomedicine, Plga nanoparticles},
	issn = {1388-0764},
	doi = {10.1007/s11051-010-9979-1},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-79956290523\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Escribano, Elvira and Domenech, Josep and Queralt, Josep and Freixes, Joan}
}
@article {Jones2009,
	title = {{Area selection for diamonds using magnetotellurics: Examples from southern Africa}},
	journal = {Lithos},
	volume = {112},
	year = {2009},
	month = {nov},
	pages = {83{\textendash}92},
	abstract = {Southern Africa, particularly the Kaapvaal Craton, is one of the world{\textquoteright}s best natural laboratories for studying the lithospheric mantle given the wealth of xenolith and seismic data that exist for it. The Southern African Magnetotelluric Experiment (SAMTEX) was launched to complement these databases and provide further constraints on physical parameters and conditions by obtaining information about electrical conductivity variations laterally and with depth. Initially it was planned to acquire magnetotelluric data on profiles spatially coincident with the Kaapvaal Seismic Experiment, however with the addition of seven more partners to the original four through the course of the experiment, SAMTEX was enlarged from two to four phases of acquisition, and extended to cover much of Botswana and Namibia. The complete SAMTEX dataset now comprises MT data from over 730 distinct locations in an area of over one million square kilometres, making SAMTEX the largest regional-scale MT experiment conducted to date. Preliminary images of electrical resistivity and electrical resistivity anisotropy at 100 km and 200 km, constructed through approximate one-dimensional methods, map resistive regions spatially correlated with the Kaapvaal, Zimbabwe and Angola Cratons, and more conductive regions spatially associated with the neighbouring mobile belts and the Rehoboth Terrane. Known diamondiferous kimberlites occur primarily on the boundaries between the resistive or isotropic regions and conductive or anisotropic regions. Comparisons between the resistivity image maps and seismic velocities from models constructed through surface wave and body wave tomography show spatial correlations between high velocity regions that are resistive, and low velocity regions that are conductive. In particular, the electrical resistivity of the sub-continental lithospheric mantle of the Kaapvaal Craton is determined by its bulk parameters, so is controlled by a bulk matrix property, namely temperature, and to a lesser degree by iron content and composition, and is not controlled by contributions from interconnected conducting minor phases, such as graphite, sulphides, iron oxides, hydrous minerals, etc. This makes quantitative correlations between velocity and resistivity valid, and a robust regression between the two gives an approximate relationship of Vs [m/s] = 0.045 * log(resistivity [ohm m]) + 4.5. {\textcopyright} 2009.},
	keywords = {Cratonic lithosphere, Diamond exploration, Electrical conductivity, Kaapvaal Craton, Sub-continental lithospheric mantle, Zimbabwe Craton},
	issn = {00244937},
	doi = {10.1016/j.lithos.2009.06.011},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-72149117671\&partnerID=tZOtx3y1},
	author = {Jones, Alan G. and Evans, Rob L. and Muller, Mark R. and Hamilton, Mark P. and Miensopust, Marion P. and Garcia, Xavier and Cole, Patrick and Ngwisanyi, Tiyapo and Hutchins, David and Fourie, C.J.S. and Jelsma, Hielke and Evans, Shane and Aravanis, Theo and Pettit, Wayne and Webb, Sue and Wasborg, Jan}
}
@article {Latham2009,
	title = {{Coupled FEMDEM/Fluids for coastal engineers with special reference to armour stability and breakage}},
	journal = {Geomechanics and Geoengineering},
	volume = {4},
	number = {1},
	year = {2009},
	month = {mar},
	pages = {39{\textendash}53},
	abstract = {Sea-level rise and increased storminess present huge challenges to coastal engineers worldwide. The seaward slope of many breakwaters and shoreline defence structures consists of thousands of interlocking units of concrete or rock making up a massive granular defence against wave attack. The units are placed freely to form an armour layer which is intended to both dissipate wave energy and remain structurally stable. Design guidance on the mass and shape of these units is based on empirical equations derived from Froude scale physical model tests. The two main failure modes for concrete armour layers are displacement (hydraulic instability) and breakage (structural instability) which are strongly coupled. Breakage mechanisms cannot all be faithfully reproduced under scaled physical models. Fundamental understanding of the forces governing such wave-structure interaction remains poor and unit breakages continue to baffle the designers of concrete armour units. This paper illustrates a range of DEM and FEMDEM methods being developed to model the granular solid skeleton of freely packed brittle units. Such discrete element methods are increasingly being used by engineers for solids modelling. They are especially powerful when coupled with a CFD model which can resolve ocean wave dynamics. The aim is to describe a framework for coupled modelling technologies applicable to coastal engineering problems. Preliminary simulation test cases, still at proof of concept stage, but based on a wealth of validation studies are presented. Thus, we report a snap-shot of progress towards a future where designers combine multi-physics numerical technology with knowledge from scalled physical models for a better understanding of wave energy turbulence, block movement, and internal stresses within armour units.},
	keywords = {Breakwaters, Concrete armour units, Discrete element method, Finite element method, Fluid coupling, Ware-structure interaction},
	issn = {1748-6025},
	doi = {10.1080/17486020902767362},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-68149172944\&partnerID=tZOtx3y1},
	author = {Latham, John-Paul and Mindel, Julian and Xiang, Jiansheng and Guises, Romain and Garcia, Xavier and Pain, Chris and Gorman, Gerard and Piggott, Matthew and Munjiza, Antonio}
}
@article {Garcia2009,
	title = {{Numerical study of the effects of particle shape and polydispersity on permeability}},
	journal = {Physical Review E},
	volume = {80},
	number = {2},
	year = {2009},
	month = {aug},
	pages = {021304},
	abstract = {We study through numerical simulations the dependence of the hydraulic permeability of granular materials on the particle shape and the grain size distribution. Several models of sand are constructed by simulating the settling under gravity of the grains; the friction coefficient is varied to construct packs of different porosity. The size distribution and shapes of the grains mimic real sands. Fluid flow is simulated in the resulting packs using a finite element method and the permeability of the packs is successfully compared with available experimental data. Packs of nonspherical particles are less permeable than sphere packs of the same porosity. Our results indicate that the details of grain shape and size distribution have only a small effect on the permeabilty of the systems studied. {\textcopyright} 2009 The American Physical Society.},
	issn = {1539-3755},
	doi = {10.1103/PhysRevE.80.021304},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-70349241904\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Akanji, Lateef and Blunt, Martin and Matthai, Stephan and Latham, John}
}
@article {Latham2008a,
	title = {{Modelling of massive particulates for breakwater engineering using coupled FEMDEM and CFD}},
	journal = {Particuology},
	volume = {6},
	number = {6},
	year = {2008},
	month = {dec},
	pages = {572{\textendash}583},
	abstract = {The seaward slope of many breakwaters consists of thousands of interlocking units of rock or concrete comprising a massive granular system of large elements each weighing tens of tonnes. The dumped quarry materials in the core are protected by progressively coarser particulates. The outer armour layer of freely placed units is intended to both dissipate wave energy and remain structurally stable as strong flows are drawn in and out of the particulate core. Design guidance on the mass and shape of these units is based on empirical equations derived from scaled physical model tests. The main failure mode for armour layers exposed to severe storms is hydraulic instability where the armour units of concrete or rock are subjected to uplift and drag forces which can in turn lead to rocking, displacement and collisions sufficient to cause breakage of units. Recently invented armour unit designs making up such granular layered system owe much of their success to the desirable emergent properties of interlock and porosity and how these combine with individual unit structural strength and inertial mass. Fundamental understanding of the forces governing such wave-structure interaction remains poor. We use discrete element and combined finite-discrete element methods to model the granular solid skeleton of randomly packed units coupled to a CFD code which resolves the wave dynamics through an interface tracking technique. The CFD code exploits several methods including a compressive advection scheme, node movement, and general mesh optimization. We provide the engineering context and report progress towards the numerical modelling of instability in these massive granular systems. {\textcopyright} 2008 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.},
	keywords = {Armour units, Breakwater, DEM, Modelling, Wave-structure interaction},
	issn = {16742001},
	doi = {10.1016/j.partic.2008.07.010},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-57049161892\&partnerID=tZOtx3y1},
	author = {Latham, John-Paul and Munjiza, Antonio and Mindel, Julian and Xiang, Jiansheng and Guises, Romain and Garcia, Xavier and Pain, Chris and Gorman, Gerard and Piggott, Matthew}
}
@article {Garcia2008,
	title = {{Robust processing of magnetotelluric data in the AMT dead band using the continuous wavelet transform}},
	journal = {GEOPHYSICS},
	volume = {73},
	number = {6},
	year = {2008},
	month = {nov},
	pages = {F223{\textendash}F234},
	abstract = {The energy sources for magnetotellurics (MT) at frequencies above 8 Hz are electromagnetic waves generated by distant lightning storms propagating globally within the earth-ionosphere waveguide. The nature of the sources and properties of this waveguide display diurnal and seasonal variations that can cause significant signal amplitude attenuation, especially at 1-5 kHz frequencies - the so-called audiomagnetotelluric (AMT) dead band. This lack of energy results in unreliable MT response estimates; and, given that in crystalline environments ore bodies located at some 500-1000-m depth are sensed initially by AMT data within the dead band, this leads to poor inherent geometric resolution of target structures. We propose a new time-series processing technique that uses localization properties of the wavelet transform to select the most energetic events. Subsequently, two coherence thresholds and a series of robust weights are implemented to obtain the most reliable MT response estimates. Finally, errors are estimated using a nonparametric jackknife algorithm. We applied this algorithm to AMT data collected in northern Canada. These data were processed previously using traditional robust algorithms and using a telluric-telluric magnetotelluric (TTMT) technique. The results show a significant improvement in estimates for the AMT dead band and permit their quantitative interpretation. {\textcopyright} 2008 Society of Exploration Geophysicists. All rights reserved.},
	issn = {0016-8033},
	doi = {10.1190/1.2987375},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-57149105924\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Jones, Alan G.}
}
@article {Garcia2008a,
	title = {{Strong-weak network anisotropy switching and hysteresis in three-dimensional granular materials}},
	journal = {Physical Review E},
	volume = {78},
	number = {2},
	year = {2008},
	pages = {021305},
	abstract = {We address hysteresis of three-dimensional polydisperse granular packs, comparing macro- and microscopic viewpoints, to reveal their elastic/inelastic mechanics and force network anisotropy. During the uniaxial loading-unloading cycle of an appropriately prepared pack, one can decompose the force network into weak and strong subnetworks. The first stages of loading exhibit arching, where all the fabric displays negative anisotropy. For later stages, the strong (weak) network shows positive (negative) anisotropy. On unloading, the force network progresses to a fabric wide hydrostatic point, where the anisotropies of the weak and strong subnetworks switch signs. During the loading stage, a Mohr circle analysis permits the identification of a well-defined macroscopic internal friction angle, whose value is larger than that of grain-grain interactions. To analyze unloading, a generalized local Coulomb-friction argument predicts a continuously changing friction angle, that vanishes at the hydrostatic point. A suggestive interplay between microscopic friction and fabric structure, at different loding stages, is proposed as the mechanism for the emergence of a macro internal friction angle. {\textcopyright} 2008 The American Physical Society.},
	issn = {1539-3755},
	doi = {10.1103/PhysRevE.78.021305},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-50849085166\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Medina, Ernesto}
}
@article {Latham2008,
	title = {{Three-dimensional particle shape acquisition and use of shape library for DEM and FEM/DEM simulation}},
	journal = {Minerals Engineering},
	volume = {21},
	number = {11},
	year = {2008},
	month = {oct},
	pages = {797{\textendash}805},
	abstract = {Numerical simulation that will capture the complex behaviour of rock fragment systems, e.g., in mining and civil engineering, requires both the computational mechanics capability to model particle interactions between complex shapes and an associated means to represent the kind of arbitrary or angular geometry relevant to problems involving rock fragments. This paper is concerned less with the modelling and more with the representation. Here, we focus on representation geared to {\textquoteright}soft contact{\textquoteright} modelling using either combined finite-discrete element (FEM/DEM) methods, or non-spherical DEM methods such as multi-sphere approximations of irregular geometry. 3D laser ranging (LADAR) is used to capture astonishingly realistic rock aggregate geometries. We report on the work flow procedures to generate computationally meshed virtual particles for modelling. The design of a shape library and a suggested procedure for selecting virtual particles for input to FEM/DEM or DEM models is discussed together with the use of inertia moments for shape descriptors. Use of the shape library for shape descriptor analysis is also illustrated. DEM simulations of packing using irregular particles from the shape library are presented. {\textcopyright} 2008 Elsevier Ltd. All rights reserved.},
	keywords = {Discrete element modelling, Gravity concentration, Mineral processing, Simulation, Sorting methods},
	issn = {08926875},
	doi = {10.1016/j.mineng.2008.05.015},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-50149086948\&partnerID=tZOtx3y1},
	author = {Latham, John-Paul and Munjiza, Antonio and Garcia, Xavier and Xiang, Jiansheng and Guises, Romain}
}
@article {Garcia2007,
	title = {{Acoustic response of cemented granular sedimentary rocks: Molecular dynamics modeling}},
	journal = {Physical Review E},
	volume = {75},
	number = {6},
	year = {2007},
	month = {jun},
	pages = {061308},
	abstract = {The effect of cementation processes on the acoustical properties of sands is studied via molecular dynamics simulation methods. We propose numerical methods where the initial uncemented sand is built by simulating the settling process of sediments. Uncemented samples of different porosity are considered by emulating natural mechanical compaction of sediments due to overburden. Cementation is considered through a particle-based model that captures the underlying physics behind the process. In our simulations, we consider samples with different degrees of compaction and cementing materials with distinct elastic properties. The microstructure of cemented sands is taken into account while adding cement at specific locations within the pores, such as grain-to-grain contacts. Results show that the acoustical properties of cemented sands are strongly dependent on the amount of cement, its stiffness relative to the hosting medium, and its location within the pores. Simulation results are in good correspondence with available experimental data and compare favorably with some theoretical predictions for the sound velocity within a range of cement saturation, porosity, and confining pressure. {\textcopyright} 2007 The American Physical Society.},
	issn = {1539-3755},
	doi = {10.1103/PhysRevE.75.061308},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-34547305692\&partnerID=tZOtx3y1},
	author = {Garcia, Xavier and Medina, Ernesto}
}
