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  • Journal article
    Brito-Parada PR, Cilliers JJ, 2012,

    Experimental and numerical studies of launder configurations in a two-phase flotation system

    , Minerals Engineering
  • Journal article
    Piotrowski M, McGilvary G, Sloan T, Mewissen M, Lloyd A, Forster T, Mitchell L, Ghazal P, Hill Jet al., 2012,

    Exploiting Parallel R in the Cloud with SPRINT

    , Methods of Information in Medicine
  • Journal article
    Jackson MD, Butler AP, Vinogradov J, 2012,

    Measurements of Spontaneous Potential in Chalk with Application to Aquifer Characterisation in the Southern UK

    , Quarterly Journal of Engineering Geology and Hydrogeology
  • Journal article
    Jackson MD, Gulamali MY, Leinov E, Saunders JH, Vinogradov Jet al., 2012,

    Spontaneous Potentials in Hydrocarbon Reservoirs during Waterflooding: Application to Waterfront Monitoring

    , SPE Journal
  • Journal article
    Bray VJ, Schenk PM, Melosh HJ, Morgan JV, Collins GSet al., 2012,

    Ganymede crater dimensions – Implications for central peak and central pit formation and development

    , Icarus, Vol: 217, Pages: 115-129

    The morphology of impact craters on the icy Galilean satellites differs from craters on rocky bodies. Thedifferences are thought due to the relative weakness of ice and the possible presence of sub-surface waterlayers. Digital elevation models constructed from Galileo images were used to measure a range of dimensionsof craters on the dark and bright terrains of Ganymede. Measurements were made from multipleprofiles across each crater, so that natural variation in crater dimensions could be assessed and averagedscaling trends constructed. The additional depth, slope and volume information reported in this work hasenabled study of central peak formation and development, and allowed a quantitative assessment of thevarious theories for central pit formation. We note a possible difference in the size-morphology progressionbetween small craters on icy and silicate bodies, where central peaks occur in small craters beforethere is any slumping of the crater rim, which is the opposite to the observed sequence on the Moon. Conversely,our crater dimension analyses suggest that the size-morphology progression of large lunar cratersfrom central peak to peak-ring is mirrored on Ganymede, but that the peak-ring is subsequentlymodified to a central pit morphology. Pit formation may occur via the collapse of surface material intoa void left by the gradual release of impact-induced volatiles or the drainage of impact melt intosub-crater fractures.

  • Journal article
    Brito-Parada PR, Kramer SC, Wilson CR, Pain CC, Neethling SJ, Cilliers JJet al., 2012,

    A finite element formulation to model the flow of flotation foams

  • Journal article
    Brito-Parada PR, Neethling SJ, Cilliers JJ, 2012,

    The advantages of using mesh adaptivity to model the drainage of liquid in froths

    , Minerals Engineering, Vol: 33, Pages: 80-86
  • Journal article
    Saunders JH, Jackson MD, Pain CC, Vinogradov J, Saunders JH, Jackson MD, Gulamali MY, Vinogradov J, Pain CC, Saunders JH, Jackson MD, Gulamali MY, Vinogradov Jet al., 2012,

    Streaming potentials in hydrocarbon reservoir conditions

    , Geophysics, Vol: 77, Pages: E77-E90
  • Journal article
    Hill J, Piggott MD, Ham DA, Popova EE, Srokosz MAet al., 2012,

    On the performance of a generic length scale turbulence model within an adaptive finite element ocean model

    , Ocean Modelling, Vol: 56, Pages: 1-15

    Research into the use of unstructured mesh methods for ocean modelling has been growing steadily in the last few years. One advantage of using unstructured meshes is that one can concentrate resolution where it is needed. In addition, dynamic adaptive mesh optimisation (DAMO) strategies allow resolution to be concentrated when this is required. Despite the advantage that DAMO gives in terms of improving the spatial resolution where and when required, small-scale turbulence in the oceans still requires parameterisation. A two-equation, generic length scale (GLS) turbulence model (one equation for turbulent kinetic energy and another for a generic turbulence length-scale quantity) adds this parameterisation and can be used in conjunction with adaptive mesh techniques. In this paper, an implementation of the GLS turbulence parameterisation is detailed in a non-hydrostatic, finite-element, unstructured mesh ocean model, Fluidity-ICOM. The implementation is validated by comparing to both a laboratory-scale experiment and real-world observations, on both fixed and adaptive meshes. The model performs well, matching laboratory and observed data, with resolution being adjusted as necessary by DAMO. Flexibility in the prognostic fields used to construct the error metric used in DAMO is required to ensure best performance. Moreover, the adaptive mesh models perform as well as fixed mesh models in terms of root mean square error to observation or theoretical mixed layer depths, but uses fewer elements and hence has a reduced computational cost.

  • Conference paper
    Buchan AG, Pain CC, Eaton MD, Gomes JLMA, Gorman GJ, Cooling CM, Goddard AJH, Nygaard ET, Glenn DE, Angelo PLet al., 2011,

    Dynamics and heat transfer characteristics of the water boiler reactor - SUPO

    , International Conference in Nuclear Criticality
  • Conference paper
    Buchan AG, Pain CC, Eaton MD, Gomes JLMA, Gorman GJ, Cooling CM, Goddard AJH, Nygaard ET, Glenn DE, Angelo PNet al., 2011,

    Simulated spatially dependent transient kinetics analysis of the oak ridge Y12 Plant criticality excursion, International Conference in Nuclear Criticality

    , International Conference in Nuclear Criticality
  • Conference paper
    Baker CMJ, Buchan AG, Pain CC, Tollit B, Goffin MA, Eaton MD, Merton SR, Smedley Stevenson PN, Warner Pet al., 2011,

    Anisotropic mesh adaptivity for eigenvalue calculations using energy dependent meshes

    , International Conference in Nuclear Criticalit
  • Journal article
    Southern J, Gorman GJ, Piggott MD, Farrell PEet al., 2011,

    Parallel anisotropic mesh adaptivity with dynamic load balancing for cardiac electrophysiology

    , Journal of Computational Science, Vol: 3, Pages: 8-16
  • Journal article
    Davison TM, Collins GS, Elbeshausen D, Wuennemann K, Kearsley Aet al., 2011,

    Numerical modeling of oblique hypervelocity impacts on strong ductile targets

    , METEORITICS & PLANETARY SCIENCE, Vol: 46, Pages: 1510-1524, ISSN: 1086-9379
  • Journal article
    Collins GS, Elbeshausen D, Davison TM, Robbins SJ, Hynek BMet al., 2011,

    The size-frequency distribution of elliptical impact craters

    , Earth and Planetary Science Letters, Vol: 310, Pages: 1-8, ISSN: 0012-821X
  • Journal article
    Morris GDM, Neethling SJ, Cilliers JJ, 2011,

    A Model for the Stability of Films Stabilized by Randomly Packed Spherical Particles

    , LANGMUIR, Vol: 27, Pages: 11475-11480, ISSN: 0743-7463
  • Journal article
    Jackson MD, Vinogradov J, Saunders JH, Jaafar MZet al., 2011,

    Laboratory Measurements and Numerical Modeling of Streaming Potential for Downhole Monitoring in Intelligent Wells

    , SPE JOURNAL, Vol: 16, Pages: 625-636, ISSN: 1086-055X
  • Journal article
    Morris G, Neethling SJ, Cilliers JJ, 2011,

    An investigation of the stable orientations of orthorhombic particles in a thin film and their effect on its critical failure pressure

    , JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 361, Pages: 370-380, ISSN: 0021-9797
  • Journal article
    Neethling SJ, Morris GDM, Garrett PR, 2011,

    Modeling Droplets in Plateau Borders

    , Langmuir

    It is widely known that oil droplets can decrease the stability ofaqueous films and foams. While less widely recognized, it has also beenobserved that oil droplets can, under certain circumstances, increase thestability of foams, especially if they are caught in the Plateau borders. In thispaper, how the oil droplet deforms and is, in turn, deformed by the Plateauborder is modeled using Surface Evolver. The two dimensionless parametersthat affect these shapes are the size of the oil droplet relative to the Plateauborder and the ratio of the oil water interfacial tension to the air waterinterfacial tension. The calculated pressures in all the phases were used toobtain the pressure exerted on the oil water air pseudoemulsion film, whichallows the factors that influence the stability of these droplets in the Plateauborder to be investigated. The final section of the paper demonstrates that thepresence of an oil droplet in a Plateau border can have a major influence on thedrainage of the aqueous phase along the Plateau border. This retardation of the flow would result in the oil droplets in the Plateauborders increasing the stability of foams in which they are found.

  • Journal article
    Gomes JLMA, Pain CC, Eaton MD, Tollit B, Goddard AJH, Piggott MD, Ziver K, Yamane Y, Gomes JLMA, Pain CC, Tollit B, Eaton MD, Piggott MD, Goddard AJH, Ziver AK, Yamane Yet al., 2011,

    Coupled neutronics-fluids modelling of criticality within a MOX powder system

    , PROGRESS IN NUCLEAR ENERGY, Vol: 53, Pages: 523-552, ISSN: 0149-1970

    Investigation of nuclear criticality in powder systems is necessary for the assessment of industrial plant integrity and potential radiation impacts on worker and the public health. For nuclear fuel processing, to produce fuel pellets, MOX (UO2 + PuO2) and zinc stearate (lubricant) powders are homogenised in a stirred vessel. The coupled multi-fluids (multiphase and multi-component) and neutron-radiation transport FETCH model was extended to simulate reactivity feedback mechanisms and to assess safety and potential risks of criticality incursions in 2-3D systems. This work has strengthened links with the Japan Atomic Energy Agency (JAEA), led to consultancy work with Japanese National Labs and work with Tokyo University that led on to the Todai Forum and the core to core program with Japan.

  • Conference paper
    Davison TM, Ciesla FJ, Collins GS, 2011,

    Quantification of the post-impact thermal evolution of planetesimals

    , 74th Annual Meeting of the Meteoritical-Society, Publisher: Wiley-Blackwell, Pages: A53-A53, ISSN: 1086-9379
  • Conference paper
    Miljkovic K, Mannick S, Collins GS, Bland PAet al., 2011,


    , 74th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A161-A161, ISSN: 1086-9379
  • Conference paper
    Collins GS, Davison TM, Ciesla FJ, 2011,

    The effects of planetesimal collisions

    , 74th Annual Meeting of the Meteoritical-Society, Publisher: Wiley-Blackwell, Pages: A46-A46, ISSN: 1086-9379
  • Conference paper
    Bland PA, Muxworthy AR, Collins GS, Moore J, Davison TM, Ciesla FJet al., 2011,

    Heterogeneous shock in porous chondrites: Implications for Allende magnetization

    , 74th Annual Meeting of the Meteoritical-Society, Publisher: Wiley-Blackwell, Pages: A22-A22, ISSN: 1086-9379
  • Journal article
    Wozniakiewicz PJ, Ishii HA, Kearsley AT, Burchell MJ, Bland PA, Bradley JP, Dai Z, Teslich N, Collins GS, Cole MJ, Russell SSet al., 2011,

    Investigation of iron sulfide impact crater residues: A combined analysis by scanning and transmission electron microscopy

    , METEORITICS & PLANETARY SCIENCE, Vol: 46, Pages: 1007-1024, ISSN: 1086-9379
  • Journal article
    Ardjmandpour N, Pain C, Singer J, Saunders J, Aristodemou E, Carter Jet al., 2011,

    Artificial neural network forward modelling and inversion of electrokinetic logging data

    , GEOPHYSICAL PROSPECTING, Vol: 59, Pages: 721-748, ISSN: 0016-8025
  • Journal article
    Wang H, Colvile RN, Pain C, Aristodemou E, ApSimon HMet al., 2011,

    Understanding peak pedestrian exposures due to traffic emissions within the urban environment

  • Journal article
    Gulamali MY, Leinov E, Jackson MD, 2011,

    Self-potential anomalies induced by water injection into hydrocarbon reservoirs

    , Geophysics, Vol: 76, Pages: F283-F292, ISSN: 1942-2156

    The injection of cold water into a hydrocarbon reservoir containingrelatively warmer, more saline formation brine may generateself-potential anomalies as a result of electrokinetic,thermoelectric, and=or electrochemical effects. We havenumerically assessed the relative contributions of these effectsto the overall self-potential signal generated during oil productionin a simple hydrocarbon reservoir model. Our aim was todetermine if measurements of self-potential at a production wellcan be used to detect the movement of water toward the well.The coupling coefficients for the electrochemical and thermoelectricpotentials are uncertain, so we considered four differentmodels for them. We also investigated the effect of altering thesalinities of the formation and injected brines. We found thatthe electrokinetic potential peaked at the location of the saturationfront (reaching values of 0.2 mV even for the most salinebrine considered). Moreover, the value at the production wellincreased as the front approached the well, exceeding the noiselevel ( 0.1 mV). Thermoelectric effects gave rise to largerpotentials in the reservoir (10 mV), but values at the wellwere negligible ð Þ .0:1 mV until after water breakthroughbecause of the lag in the temperature front relative to the saturationfront. Electrochemical potentials were smaller in magnitudethan thermoelectric potentials in the reservoir but were measurableð Þ > 0:1 mV at the well because the salinity front wasclosely associated with the saturation front. When the formationbrine was less saline (1 mol=liter), electrokinetic effects dominated;at higher salinities (5 mol=liter), electrochemicaleffects were significant. We concluded that the measurement ofself-potential signals in a production well may be used to monitorthe movement of water in hydrocarbon reservoirs duringproduction, but further research is required to understand thethermoelectric and electrochemical coupling coefficients in partiallysatu

  • Journal article
    Davies DR, Wilson CR, Kramer SC, 2011,

    Fluidity: A fully unstructured anisotropic adaptive mesh computational modeling framework for geodynamics

  • Journal article
    Tong M, Cole KE, Neethling SJ, 2011,

    Drainage and stability of 2D foams: foam behaviour in vertical Hele-Shaw cells

    , Colloids and Surfaces A: Physicochemical and Engineering Aspects

    An integrated numerical model was developed to predict the spatial and temporal evolution of the bubble size distribution within foams. In order to validate the modelling, experiments in a vertical pseudo-2D Hele-Shaw cell were carried out since the bubble size distribution in this system can be readily measured. The model combines a population balance sub-model for predicting the bubble size with a liquid drainage sub-model. The liquid drainage model is a version of the standard foam drainage equation that has been modified to account for a pseudo-2D geometry. It has also been modified to account for the confined shape of the bubble and the size of the gap between the vessel walls, as well as the different Plateau border shapes and orientations found in this system. The population balance model is used to predict the change of bubble size as films fail and bubbles coalesce. The population balance and liquid drainage models are fully coupled, with the bubble size distribution influencing the drainage and the capillary pressure exerted by the Plateau borders influencing coalescence. In order to validate this integrated numerical model, the size of bubbles in a rising pseudo-2D foam was measured with image analysis. The numerical model reasonably predicted the evolution of the mean bubble size and was in strong agreement with the bubble size distribution over the depth of the pseudo-2D foam. The predictions are very close to the measured experimental data.

  • Journal article
    Ran L, Jones SA, Embley B, Tong MM, Garrett PR, Cox SJ, Grassia P, Neethling SJet al., 2011,

    Characterisation, modification and mathematical modelling of sudsing

  • Journal article
    Collins GS, Melosh HJ, Wunnemann K, 2011,

    Improvements to the epsilon-alpha porous compaction model for simulating impacts into high-porosity solar system objects


    We describe improvements to the epsilon-alpha porous compaction model for simulating solar system impacts. To improve the treatment of highly porous materials, we modified the epsilon-alpha model to account for thermal expansion of the matrix during compaction. We validated the improved model by demonstrating good agreement between numerically computed Hugoniot curves for porous iron (up to initial porosities of similar to 80%) using the improved epsilon-alpha model and experimentally-derived Hugoniot data. Moreover, we verified that the model improvements are easily implemented into a hydrocode and preserve the efficiency advantage of a strain-based compaction function. We used the improved epsilon-alpha porous compaction model in the iSALE hydrocode to reproduce 2-km/s porous-target laboratory impact experiments. The simulation results were in qualitative agreement with the experiments but produced craters that were consistently deeper and larger in volume than the experiments. The results of the hydrocode simulations and laboratory experiments show a reduction in crater efficiency with increasing porosity. This reduction is more dramatic if the impactor density and velocity are higher. (C) 2010 Elsevier Ltd. All rights reserved.

  • Conference paper
    Merton SR, Smedley-Stevenson RP, Pain CC, ElSheikh AH, Buchan AGet al., 2011,

    An Adjoint Based Scheme for Eigenvalue Error Improvement

    , International Conference on Mathematics, Computational Methods & Reactor Physics
  • Journal article
    Buchan AG, Merton SR, Pain CC, Smedley-Stevenson RPet al., 2011,

    Riemann boundary conditions for the Boltzmann transport equation using arbitrary angular approximations

    , ANNALS OF NUCLEAR ENERGY, Vol: 38, Pages: 1186-1195, ISSN: 0306-4549
  • Journal article
    Deveugle PEK, Jackson MD, Hampson GJ, Farrell ME, Sprague AR, Stewart J, Calvert CSet al., 2011,

    Characterization of stratigraphic architecture and its impact on fluid flow in a fluvial-dominated deltaic reservoir analog: Upper Cretaceous Ferron Sandstone Member, Utah

    , AAPG Bulletin, Vol: 95, Pages: 693-727, ISSN: 0149-1423
  • Journal article
    Morris G, Neethling SJ, Cilliers JJ, 2011,

    A model for investigating the behaviour of non-spherical particles at interfaces

    , JOURNAL OF COLLOID AND INTERFACE SCIENCE, Vol: 354, Pages: 380-385, ISSN: 0021-9797
  • Conference paper
    Rokos G, Gorman G, Kelly PHJ, 2011,

    Accelerating Anisotropic Mesh Adaptivity on nVIDIA's CUDA Using Texture Interpolation

    , 17th International Euro-Par Conference on Parallel Processing, Publisher: SPRINGER-VERLAG BERLIN, Pages: 387-398, ISSN: 0302-9743
  • Conference paper
    Nelson R, Piggott M, Wilson C, Kramer Set al., 2011,

    Compressible Flows on Adaptive and Unstructured Meshes with FLUIDITY

    , 6th International Conference on Fluid Mechanics, Publisher: AMER INST PHYSICS, ISSN: 0094-243X
  • Journal article
    Maddison JR, Marshall DP, Pain CC, Piggott MDet al., 2011,

    Accurate representation of geostrophic and hydrostatic balance in unstructured mesh finite element ocean modelling

    , OCEAN MODELLING, Vol: 39, Pages: 248-261, ISSN: 1463-5003
  • Journal article
    Hiester H, Piggott MD, Allison PA, 2011,

    The impact of mesh adaptivity on the gravity current front speed in a two-dimensional lock-exchange

    , Ocean Modelling, ISSN: 1463-5003
  • Journal article
    Ratcliffe A, Win C, Vinje V, Conroy G, Warner M, Umpleby A, Stekl I, Nangoo T, Bertrand Aet al., 2011,

    Full waveform inversion: A North Sea OBC case study

    , SEG Technical Program Expanded Abstracts, Vol: 30, Pages: 2384-2388, ISSN: 1052-3812

    Full Waveform Inversion (FWI) aims to obtain superior velocity models by minimizing the difference between observed and modelled seismic waveforms. We apply FWI to a North Sea OBC field data set with wide azimuths and more than 10 km long offsets. We discuss the methodology used and the associated practical issues. Our FWI result has revealed detailed velocity features associated with thin, gas-charged layers and faulting in the shallow sections of the model. We demonstrate that this velocity update has improved the imaging of the deeper structures. © 2011 Society of Exploration Geophysicists.

  • Book chapter
    Allison PA, Bottjer DJ, 2011,

    Taphonomy: Bias and Process Through Time

    , Taphonomy: Bias and Process Through Time (Volume 32 in the Topics in Geobiology series), Editors: Allison, Bottjer, Publisher: Springer, Pages: 1-18, ISBN: 978-90-481-8642-6
  • Journal article
    Vinogradov J, 2011,

    Multiphase streaming potential in sandstones saturated with gas/brine and oil/brine during drainage and imbibition

    , Geophysical Research Letters
  • Book chapter
    Brett CE, Allison PA, Hendy AJW, 2011,

    Comparative taphonomy and sedimentology of small-scale mixed carbonate/siliciclastic cycles: Synopsis of Phanerozoic examples

    , Taphonomy: Bias and Process Through Time (Volume 32 in the Topics in Geobiology series), Editors: Allison, Bottjer, Publisher: Springer, Pages: 107-198, ISBN: 978-90-481-8642-6
  • Conference paper
    Cilliers JJ, Brito-Parada PR, Cole KE, Shean BJ, Hadler Ket al., 2011,

    Advances in flotation using positron emission particle tracking and 3D simulation

    , Procemin
  • Conference paper
    Latham J-P, Xiang J, Harrison JP, Munjiza Aet al., 2011,

    Development of Virtual Geoscience Simulation Tools, VGeST for irregular blocky rock applications in rock engineering using the combined finite discrete element method, FEMDEM

    , 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Publisher: Curran Associates, Pages: 965-976
  • Conference paper
    xiang J, Latham J-P, Harrison JP, 2011,

    A Numeric Simulation of Rock Avalanches Using the Combined Finite-Discrete Element Method,FEMDEM

    , 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Pages: 921-927
  • Conference paper
    Harrison JP, Xiang J, Latham JP, 2011,

    Stress Heterogeneity in a Fractured Rock Mass Modelled with the Combined Finite-DiscreteElement Method

    , 44th US Rock Mechanics Symposium and 5th U.S.-Canada Rock Mechanics Symposium, Pages: 1051-1056
  • Conference paper
    Latham J-P, Xiang J, 2011,

    A numerical investigation of the influence of friction and vibration on laboratory scale armour unit layers

    , 6th International Conference on Coastal Structures, Publisher: World Scientific Publishing Company Pte Ltd.
  • Conference paper
    Xiang J, Latham J-P, Zimmer D, Baird WFet al., 2011,

    Modelling breakwater armour layers and the dynamic response of armour units.

    , 6th International Conference on Coastal Structures

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