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  • Journal article
    Guilbert AAY, Frost JM, Agostinelli T, Pires E, Lilliu S, Macdonald JE, Nelson Jet al., 2014,

    Influence of Bridging Atom and Side Chains on the Structure and Crystallinity of Cyclopentadithiophene-Benzothiadiazole Polymers

    , CHEMISTRY OF MATERIALS, Vol: 26, Pages: 1226-1233, ISSN: 0897-4756
  • Journal article
    van Reeuwijk M, Holzner M, 2014,

    The turbulence boundary of a temporal jet

    , Journal of Fluid Mechanics, Vol: 739, Pages: 254-275, ISSN: 0022-1120

    We examine the structure of the turbulence boundary of a temporal plane jet at Re=5000 using statistics conditioned on the enstrophy. The data is obtained by direct numerical simulation and threshold values span 24 orders of magnitude, ranging from essentially irrotational fluid outside the jet to fully turbulent fluid in the jet core. We use two independent estimators for the local entrainment velocity vn based on the enstrophy budget. The data show clear evidence for the existence of a viscous superlayer (VSL) that envelopes the turbulence. The VSL is a nearly one-dimensional layer with low surface curvature. We find that both its area and viscous transport velocity adjust to the imposed rate of entrainment so that the integral entrainment flux is independent of threshold, although low-Reynolds-number effects play a role for the case under consideration. This threshold independence is consistent with the inviscid nature of the integral rate of entrainment. A theoretical model of the VSL is developed that is in reasonably good agreement with the data and predicts that the contribution of viscous transport and dissipation to interface propagation have magnitude 2vn and −vn , respectively. We further identify a turbulent core region (TC) and a buffer region (BR) connecting the VSL and the TC. The BR grows in time and inviscid enstrophy production is important in this region. The BR shows many similarities with the turbulent–non-turbulent interface (TNTI), although the TNTI seems to extend into the TC. The average distance between the TC and the VSL, i.e. the BR thickness is about 10 Kolmogorov length scales or half a Taylor length scale, indicating that intense turbulent flow regions and viscosity-dominated regions are in close proximity.
  • Journal article
    Zhou Z, Dionisio KL, Verissimo TG, Kerr AS, Coull B, Howie S, Arku RE, Koutrakis P, Spengler JD, Fornace K, Hughes AF, Vallarino J, Agyei-Mensah S, Ezzati Met al., 2014,

    Chemical Characterization and Source Apportionment of Household Fine Particulate Matter in Rural, Peri-urban, and Urban West Africa

    , ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 48, Pages: 1343-1351, ISSN: 0013-936X
  • Journal article
    Farrell PE, Cotter CJ, Funke SW, 2014,

    A framework for the automation of generalised stability theory

    , SIAM Journal on Scientific Computing, Vol: 36, Pages: C25-C48
  • Journal article
    Cesaroni G, Forastiere F, Stafoggia M, Andersen ZJ, Badaloni C, Beelen R, Caracciolo B, de Faire U, Erbel R, Eriksen KT, Fratiglioni L, Galassi C, Hampel R, Heier M, Hennig F, Hilding A, Hoffmann B, Houthuijs D, Joeckel K-H, Korek M, Lanki T, Leander K, Magnusson PKE, Migliore E, Ostenson C-G, Overvad K, Pedersen NL, Pekkanen JJ, Penell J, Pershagen G, Pyko A, Raaschou-Nielsen O, Ranzi A, Ricceri F, Sacerdote C, Salomaa V, Swart W, Turunen AW, Vineis P, Weinmayr G, Wolf K, de Hoogh K, Hoek G, Brunekreef B, Peters Aet al., 2014,

    Long term exposure to ambient air pollution and incidence of acute coronary events: prospective cohort study and meta-analysis in 11 European cohorts from the ESCAPE Project

    , BMJ-BRITISH MEDICAL JOURNAL, Vol: 348, ISSN: 0959-535X
  • Journal article
    Bell RE, Jackson CAL, Elliott GM, Gawthorpe RL, Sharp IR, Michelsen L, Bell R, Jackson CA-L, Elliott G, Gawthorpe R, Sharp IR, Michelsen Let al., 2014,

    Insights into the development of major rift-related unconformities from geologically constrained subsidence modelling: Halten Terrace, offshore mid Norway

    , Basin Research, Vol: 26, Pages: 203-224

    Due to the effects of sediment compaction, thermal subsidence and ‘post-rift’ fault reactivation, the present-day geometry of buried, ancient rift basins may not accurately reflect the geometry of the basin at any stage of its syn-rift evolution. An understanding of the geometry of a rift basin through time is crucial for resolving the dynamics of continental rifting and in assessing the hydrocarbon prospectivity of such basins. In this study, we have restored the Late Jurassic–Early Cretaceous geometry of the southern Halten Terrace, offshore mid Norway, using a combination of well log- and core-derived, sedimentological and stratigraphic data, seismic-stratigraphic observations and reverse subsidence modelling. This integrated geological and geophysical approach has allowed the large number of input parameters involved in flexural backstripping and post-rift thermal subsidence modelling to be constrained. We have thus been able to determine the regional structure of the basin at the end of the Late Jurassic–Early Cretaceous rift phase and the associated amount of crustal stretching. Our basin geometry reconstructions reveal that, during the latest syn-rift period in the Late Jurassic–Early Cretaceous, the Halten Terrace was characterized by a series of isolated depocentres, located between footwall islands, which were not connected into a single depocentre until the Late Cretaceous (Coniacian). We show that two major unconformities, which are now vertically offset by ca. 2 km and located ca. 60 km apart, formed at similar subaerial elevations in the Late Jurassic–Early Cretaceous and were subsequently vertically offset by thermally induced tilting of the basin margin. Cretaceous sediments were deposited in a single, relatively unconfined basin in water depths of 1–1.5 km. The β profile that best restores palaeobathymetry to match our geological constraints is the same as that derived from summing visible post-Late Tri
  • Journal article
    Alves TM, Bell RE, Jackson CA-L, Minshull TA, Alves TM, Bell RE, Jackson CAL, Minshull TAet al., 2014,

    Deep-water continental margins: geological and economic frontiers

    , Basin Research, Vol: 26, Pages: 3-9

    Deep-water margins have been the focus of considerable research during the past decade. They comprise vast, underexplored regions, in which only recently have improvements in seismic imaging and drilling technology allowed the discovery of significant hydrocarbon accumulations. This volume comprises of a series of manuscripts based on studies from continental margins bordering India, East Africa, Australia, China, Norway, the United Kingdom, Iberia, Newfoundland, the southern US, West Africa and Brazil, thus offering a global perspective on the evolution and economic significance of deep-water margins. The articles in this volume examine: (i) the quantification of extension and hyperextension in distal parts of continental margins, and their relationship with regional subsidence, (ii) the importance of magmatism in the structural and thermal evolution of rifted continental margins, (iii) the processes driving and the significance of regional exhumation during and after syn-rift stretching, (iv) the tectonic setting of salt basins and (v) depositional patterns along deep-water margins. To complement this work, we present a personal view of some of the specific questions that need to be addressed in the next few years of deep-water continental margin research.
  • Journal article
    Parpas P, Webster M, 2014,

    A stochastic multiscale model for electricity generation capacity expansion

    , European Journal of Operational Research, Vol: 232, Pages: 359-374, ISSN: 0377-2217

    Long-term planning for electric power systems, or capacity expansion, has traditionally been modeled using simplified models or heuristics to approximate the short-term dynamics. However, current trends such as increasing penetration of intermittent renewable generation and increased demand response requires a coupling of both the long and short term dynamics. We present an efficient method for coupling multiple temporal scales using the framework of singular perturbation theory for the control of Markov processes in continuous time. We show that the uncertainties that exist in many energy planning problems, in particular load demand uncertainty and uncertainties in generation availability, can be captured with a multiscale model. We then use a dimensionality reduction technique, which is valid if the scale separation present in the model is large enough, to derive a computationally tractable model. We show that both wind data and electricity demand data do exhibit sufficient scale separation. A numerical example using real data and a finite difference approximation of the Hamilton–Jacobi–Bellman equation is used to illustrate the proposed method. We compare the results of our approximate model with those of the exact model. We also show that the proposed approximation outperforms a commonly used heuristic used in capacity expansion models.
  • Journal article
    Irvine EA, Hoskins BJ, Shine KP, 2014,

    A Lagrangian analysis of ice-supersaturated air over the North Atlantic

    , JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, Vol: 119, Pages: 90-100, ISSN: 2169-897X
  • Journal article
    Cotter CJ, Thuburn J, 2014,

    A finite element exterior calculus framework for the rotating shallow-water equations

    , Journal of Computational Physics, Vol: 257, Pages: 1506-1526
  • Journal article
    Read L, Madani K, Inanloo B, 2014,

    Optimality versus stability in water resource allocation

    , JOURNAL OF ENVIRONMENTAL MANAGEMENT, Vol: 133, Pages: 343-354, ISSN: 0301-4797
  • Conference paper
    Pawlak J, Polak JW, Sivakumar A, 2014,

    Microsimulation-Based Estimation of Value of Employer's Business Traveler's Value of Time: Comparison with Current Estimation Practices and Implications for Investment Appraisal

    , 93rd Annual Meeting of Transportation Research Board
  • Journal article
    Zolfaghari A, Sivakumar A, Polak JW, 2014,

    Simplified probabilistic choice set formation models in a residential location choice context

    The implementation of a theoretically sound, two-stage discrete-choice modelling paradigm incorporating probabilistic choice sets is impractical when the number of alternatives is large, which is a typical case in most spatial choice contexts. In the context of residential location choice, Kaplan et al., 2009, Kaplan et al., 2011 and Kaplan et al., 2012 (KBS) developed a semi-compensatory choice model incorporating data of individuals searching for dwellings observed using a customised real estate agency website. This secondary data is used to compute the probability of considering a choice set that takes the form of an ordered probit model. In this paper, we illustrate that the simplicity of the KBS model arises because of an unrealistic assumption that individuals' choice sets only contain alternatives that derive from their observed combination of thresholds. Relaxing this assumption, we introduce a new probabilistic choice set formation model that allows the power set to include all potential choice sets derived from variations in thresholds' combinations. In addition to extending the KBS model, our proposed model asymptotically approaches the classical Manski model, if a suitable structure is used to categorise alternatives. In order to illustrate the biases inherent in the original KBS approach, we compare it with our proposed model and the MNL model using a Monte Carlo experiment. The results of this experiment show that the KBS model causes biases in predicted market share if individuals are free to choose from any potential choice sets derived from combinations of thresholds.
  • Journal article
    Verdia P, Brandt A, Hallett JP, Ray MJ, Welton Tet al., 2014,

    Fractionation of lignocellulosic biomass with the ionic liquid 1-butylimidazolium hydrogen sulfate

    , Green Chemistry, Vol: 16, Pages: 1617-1627, ISSN: 1744-1560

    The application of the protic ionic liquid 1-butylimidazolium hydrogen sulfate in the deconstruction (aka pretreatment) and fractionation of lignocellulosic biomass has been investigated. A cellulose rich pulp and a lignin fraction were produced. The pulp was subjected to enzymatic saccharification which allowed recovery of up to 90% of the glucan as fermentable glucose. The influence of the solution acidity on the deconstruction of Miscanthus giganteus was examined by varying the 1-butylimidazole to sulfuric acid ratio. Increased acidity led to shorter pretreatment times and resulted in reduced hemicellulose content in the pulp. Addition of water to the ionic liquid resulted in enhanced saccharification yields. The ability to tune acidity through the use of protic ionic liquids offers a significant advantage in flexibility over dialkylimidazolium analogues.
  • Journal article
    Edwards CTT, Bunnefeld N, Balme GA, Milner-Gulland EJet al., 2014,

    Data-poor management of African lion hunting using a relative index of abundance

    , PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 111, Pages: 539-543, ISSN: 0027-8424
  • Journal article
    Siegert MJ, Ross N, Corr H, Smith B, Jordan T, Bingham RG, Ferraccioli F, Rippin DM, Le Brocq Aet al., 2014,

    Boundary conditions of an active West Antarctic subglacial lake: implications for storage of water beneath the ice sheet

    , CRYOSPHERE, Vol: 8, Pages: 15-24, ISSN: 1994-0416
  • Journal article
    Ritson JP, Graham NJD, Templeton MR, Clark JM, Gough R, Freeman Cet al., 2014,

    The impact of climate change on the treatability of dissolved organic matter (DOM) in upland water supplies: a UK perspective

    , Science of the Total Environment, Vol: 473-474, Pages: 714-730
  • Journal article
    Guerra C, Lanzini A, Leone P, Santarelli M, Brandon NPet al., 2014,

    Optimization of dry reforming of methane over Ni/YSZ anodes for solid oxide fuel cells

    , JOURNAL OF POWER SOURCES, Vol: 245, Pages: 154-163, ISSN: 0378-7753
  • Journal article
    D'Arcy M, Whittaker AC, 2014,

    Geomorphic constraints on landscape sensitivity to climate in tectonically active areas

    , Geomorphology, Vol: 204, Pages: 366-381

    The geomorphology of fluvial landscapes is known to record information about uplift rate, spatial patterns of faulting, and tectonic history. Data is far less available when addressing the sensitivity of common geomorphological metrics, such as channel steepness, to climatic boundary conditions. We test the relationship between channel steepness and precipitation rate by measuring a large number of channels in different mountainous areas. These regions exhibit a tenfold variation in precipitation rate between them (~ 100-1000 mm y- 1) but have similar uplift rates, allowing the tectonic variable to be controlled. By accounting for the orographic coupling of rainfall with uplifted topography, we find that channel steepness is significantly suppressed by higher precipitation rates in a measurable way that conforms to simple stream power erosion laws and empirical constraints on their parameters. We demonstrate this using modern and estimated glacial precipitation rates; and climate emerges as an important, quantifiable control on channel geometry. These findings help to explain why highly variable measurements of channel steepness are reported from different locations and provide important empirical constraints on how climate shapes tectonically active landscapes.
  • Journal article
    Bond T, Huang J, Graham NJD, Templeton MR, Bond T, Huang J, Graham NJD, Templeton MRet al., 2014,

    Examining the interrelationship between DOC, bromide and chlorine dose on DBP formation in drinking water - a case study

    , Science of the Total Environment, Vol: 470–471, Pages: 469-479
  • Journal article
    Visram AR, Cotter CJ, Cullen MJP, 2014,

    A framework for evaluating model error using asymptotic convergence in the Eady model

    , Quarterly Journal of the Royal Meteorological Society, Pages: n/a-n/a, ISSN: 0035-9009
  • Journal article
    Boot-Handford ME, Abanades JC, Anthony EJ, Blunt MJ, Brandani S, Mac Dowell N, Fernandez JR, Ferrari M-C, Gross R, Hallett JP, Haszeldine RS, Heptonstall P, Lyngfelt A, Makuch Z, Mangano E, Porter RTJ, Pourkashanian M, Rochelle GT, Shah N, Yao JG, Fennell PSet al., 2014,

    Carbon capture and storage update

    , Energy and Environmental Science, Vol: 7, Pages: 130-189, ISSN: 1754-5692

    In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.
  • Journal article
    McRae ATT, Cotter CJ, 2014,

    Energy- and enstrophy-conserving schemes for the shallow-water equations, based on mimetic finite elements

    , Quarterly Journal of the Royal Meteorological Society

    This paper presents a family of spatial discretisations of the nonlinearrotating shallow-water equations that conserve both energy and potentialenstrophy. These are based on two-dimensional mixed finite element methods, andhence, unlike some finite difference methods, do not require an orthogonalgrid. Numerical verification of the aforementioned properties is also provided.
  • Conference paper
    Niu B, Krevor S, 2014,

    The impact of reservoir conditions on the measurement of multiphase flow properties for CO2-brine systems

    , Pages: 77-81

    Successful industrial scale carbon dioxide injection into deep saline aquifers will be dependent on the ability to model the flow of the fluid and to quantify the impact of various trapping mechanisms. The effectiveness of the models is in turn dependent on high quality laboratory measurements ofbasic multiphase flow properties such as relative permeability and residual trapping at reservoir conditions. At the same time there exists general uncertainty around the few existing published data on these properties for CO2-brine systems. In this study we present results from a newly constructed reservoir condition coreflooding and imaging laboratory designed to measure multiphase flow properties, capillary pressure, relative permeability and residual trapping at a range of reservoir conditions. The proper approach to measuring relative permeability for CO2-brine system is proposed and demonstrated. The changes in residual trapping correlated to pressure, temperature, brine salinity, interfacial tension, and contact angle are also reported. We also show with a combination of simulations of corefloods and experiments performed at various conditions that high precision results can be obtained for this system when the appropriate conditions are used. Copyright © (2014) by the European Association of Geoscientists & Engineers. All rights reserved.
  • Conference paper
    Al-Menhali A, Reynolds C, Lai P, Niu B, Nicholls N, Crawshaw J, Krevor Set al., 2014,

    Advanced reservoir characterization for CO<inf>2</inf> storage

    , Pages: 503-512

    Injection of CO2 into the subsurface is of interest for CO 2 storage and enhanced oil recovery (EOR). There are, however, major unresolved questions around the multiphase flow physics and reactive processes that will take place after CO2 is injected, particularly in carbonate rock reservoirs. For example, the wetting properties of CO2-brine- rock systems will impact the efficiency of EOR operations and CO2 storage but reported contact angles range widely from strongly water-wet to intermediate wet. Similar uncertainties exist for properties including the relative permeability and the impact of chemical reaction on flow. In this presentation we present initial results from laboratory studies investigating the physics of multiphase flow and reactive transport for CO2-brine systems. We use traditional and novel core flooding techniques and x-ray imaging to resolve uncertainties around the CO2-brine contact angle, relative permeability, residual trapping, and feedbacks between chemical reaction and flow in carbonate rocks. Copyright 2014, International Petroleum Technology Conference.
  • Journal article
    Siegert MJ, Makinson K, Blake D, Mowlem M, Ross Net al., 2014,

    An assessment of deep hot-water drilling as a means to undertake direct measurement and sampling of Antarctic subglacial lakes: experience and lessons learned from the Lake Ellsworth field season 2012/13

    , ANNALS OF GLACIOLOGY, Vol: 55, Pages: 59-73, ISSN: 0260-3055
  • Journal article
    Silverwood IP, Keyworth CW, Brown NJ, Shaffer MSP, Williams CK, Hellgardt K, Kelsall GH, Kazarian SGet al., 2014,

    An Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopic Study of Gas Adsorption on Colloidal Stearate-Capped ZnO Catalyst Substrate

    , APPLIED SPECTROSCOPY, Vol: 68, Pages: 88-94, ISSN: 0003-7028
  • Journal article
    Vandeginste V, John CM, Beckert J, 2014,

    Diagenetic geobodies: Fracture-controlled burial dolomite bodies in outcrops from Northern Oman

    , Society of Petroleum Engineers - International Petroleum Technology Conference 2014, IPTC 2014: Unlocking Energy Through Innovation, Technology and Capability, Vol: 2, Pages: 1142-1152

    Diagenetic heterogeneities are difficult to predict in subsurface. Nevertheless, such heterogeneities can be crucial in hydrocarbon exploration. Diagenetic processes can significantly alter petrophysical properties of reservoir rocks, especially in carbonate rocks because of the reactive nature of the carbonate minerals. Dolomitization, i.e. the transformation of calcite (limestone) into dolomite, is a common diagenetic process in carbonate rocks. Description: an overview of the learning outcomes gained by studying fracture-related dolomite in outcrops of Oman and subsequent laboratory analysis over the last four years. A combined structural, petrographic and geochemical approach was taken to study three dolomite systems occurring in different stratigraphic host rock intervals. Application: Structurally-controlled dolomitization (i.e. dolomitization along faults and fractures) typically occurs in burial conditions, and the resulting strong permeability anisotropies caused by the dolomite textures can cause major challenges for hydrocarbon exploration. Results and Conclusions: Dolomite bodies in the Precambrian Khufai Formation are related to N-S to NNE-SSW fractures, whereas dolomite bodies that mainly occur in the Jurassic host rocks occur along reactivated WNW-ESE normal faults. These fracture-related dolomite bodies are generally less than 15 m wide, but can be up to a few hundred meters long. Late-diagenetic dolomite bodies were also recognized in Permian host rocks, where they occur at or close to the contact between Permian limestone and early-diagenetic dolomite. This late diagenetic dolomite system can be traced laterally for at least hundreds of meters and occurs in wadi's about 40 km apart. Our data indicate that there were several dolomitization events in the geological history, generating dolomite bodies with different characteristics. Technical Contributions: This highlights the needs to understand the timing and structural setting of dolomite bodies in
  • Journal article
    John CM, Vandeginste V, Jourdan AL, Kluge TM, Davis S, Sena C, Honig M, Beckert Jet al., 2014,

    Carbonate reservoir analogues and clumped isotopes: How combined geometries and geochemistry of outcrops help reservoir management in the Middle East

    , Society of Petroleum Engineers - International Petroleum Technology Conference 2014, IPTC 2014: Unlocking Energy Through Innovation, Technology and Capability, Vol: 1, Pages: 533-539

    Petroleum geologists working in carbonate plays are facing two common and inter-connected challenges linked to optimizing production. First, constraining the geometry, spatial distribution and inter-connectivity of reservoir geobodies is crucial as these properties can control the permeability anisotropy of reservoirs zones. This is difficult to do at the inter-well scale due to the limited resolution of seismic methods (20 meters or higher) compared to the size of typical reservoir geobodies (tens of centimers to meters and higher) and the very heterogeneous nature of carbonate reservoirs. Furthermore, diagenetic transformations are very important in carbonate reservoirs. Being able to fingerprint the process and timing of diagenetic transformation is crucial to a correct assessement of the distribution of cemented zones in the subsurface. The issue of diagenesis is also important for organic matter maturation and the timing of oil migration, and therefore the second challenge faced by reservoir geologists in carbonate plays is one of constraining as well as possible the thermal history of the targeted basin. This paper reports on the results of a major long-term research effort that addresses some aspects of this double challenge in the Middle East, and that focused on novel isotopic methods to constrain the thermal history of carbonate phases in the context of the geometry of geobodies measured at the outcrop. Geological work under the Qatar Carbonates and Carbon Storage Centre (QCCSRC), funded jointly by Qatar Petroleum, Shell and the Qatar Science & Technology Park, has as its long-term research goals to improve characterization of subsurface anisotropies in carbonate reservoirs, notably for CCS operations. Copyright 2014, International Petroleum Technology Conference.
  • Journal article
    Parpas P, Wiesemann W, 2014,

    Editorial to computational techniques in management science

    , Computational Management Science, Vol: 11, Pages: 3-4, ISSN: 1619-697X

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