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  • Journal article
    Bull JW, Gordon A, Law EA, Suttle KB, Milner-Gulland EJet al., 2014,

    Importance of Baseline Specification in Evaluating Conservation Interventions and Achieving No Net Loss of Biodiversity

    , CONSERVATION BIOLOGY, Vol: 28, Pages: 799-809, ISSN: 0888-8892
  • Journal article
    Huang X, Rein G, 2014,

    Smouldering combustion of peat in wildfires: Inverse modelling of the drying and the thermal and oxidative decomposition kinetics

    , Combustion and Flame, Vol: 161, Pages: 1633-1644, ISSN: 0010-2180

    Abstract Smouldering combustion is the driving phenomenon of wildfire in peatlands, like those causing haze episodes in Southeast Asia and Northeast Europe. These are the largest fires on Earth and an extensive source of greenhouse gases, but poorly understood, becoming an emerging research topic in climate-change mitigation. In this work, a series of multistep heterogeneous kinetics are investigated to describe the drying and decomposition in smouldering combustion of peat. The decomposition schemes cover a range of complexity, including 2, 3 or 4-step schemes, and up to 4 solid pseudo-species. The schemes aim to describe the simultaneous pyrolysis and oxidation reactions in smouldering fires. The reaction rates are expressed by Arrhenius law, and a lumped model of mass loss is used to simulate the degradation behaviour seen during thermogravimetric (TG) experiments in both nitrogen and air atmospheres. A genetic algorithm is applied to solve the corresponding inverse problem using TG data from the literature, and find the best kinetic and stoichiometric parameters for four types of boreal peat from different geographical locations (North China, Scotland and Siberia). The results show that at the TG level, all proposed schemes seem to perform well, with a high degree of agreement resulting from the forced optimization in the inverse problem approach. The chemical validity of the schemes is then investigated outside the TG realm and incorporated into a 1-D plug-flow model to study the reaction and the species distribution inside a peat smouldering front. Both lateral and in-depth spread modes are considered. The results show that the drying sub-front is essential, and that the best kinetics is the 4-step decomposition (one pyrolysis, and three oxidations) plus 1-step drying with 5 condensed species (water, peat, α -char, β -char, and ash). This is the first time that the smouldering kinetics and the reaction-zone structure of a peat fire are explained and
  • Journal article
    Xu W, Zhang X, Hu Q, Zhao L, Teng X, Lai W-Y, Xia R, Nelson J, Huang W, Bradley DDCet al., 2014,

    Fluorene-based cathode interlayer polymers for high performance solution processed organic optoelectronic devices

    , ORGANIC ELECTRONICS, Vol: 15, Pages: 1244-1253, ISSN: 1566-1199
  • Journal article
    Staffell I, Green R, 2014,

    How does wind farm performance decline with age?

    , RENEWABLE ENERGY, Vol: 66, Pages: 775-786, ISSN: 0960-1481
  • Journal article
    Cook CP, Hill DJ, van de Flierdt T, Williams T, Hemming SR, Dolan AM, Pierce EL, Escutia C, Harwood D, Cortese G, Gonzales JJet al., 2014,

    Sea surface temperature control on the distribution of far-traveled Southern Ocean ice-rafted detritus during the Pliocene

    , PALEOCEANOGRAPHY, Vol: 29, Pages: 533-548, ISSN: 0883-8305
  • Conference paper
    Maskell WC, Brett DJL, Brandon NP, 2014,

    Thick-film amperometric zirconia oxygen sensors: influence of cobalt oxide as a sintering aid

    , Publisher: IOP PUBLISHING LTD, ISSN: 0957-0233
  • Journal article
    Henry L-A, Frank N, Hebbeln D, Wienberg C, Robinson L, van de Flierdt T, Dahl M, Douarin M, Morrison CL, Lopez Correa M, Rogers AD, Ruckelshausen M, Roberts JMet al., 2014,

    Global ocean conveyor lowers extinction risk in the deep sea

    , DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS, Vol: 88, Pages: 8-16, ISSN: 0967-0637
  • Journal article
    Emmott CJM, Ekins-Daukes NJ, Nelson J, 2014,

    Dynamic carbon mitigation analysis: the role of thin-film photovoltaics

    , ENERGY & ENVIRONMENTAL SCIENCE, Vol: 7, Pages: 1810-1818, ISSN: 1754-5692
  • Journal article
    Hoshino E, Milner-Gulland EJ, Hillary RM, 2014,

    Why model assumptions matter for natural resource management: interactions between model structure and life histories in fishery models

    , JOURNAL OF APPLIED ECOLOGY, Vol: 51, Pages: 632-641, ISSN: 0021-8901
  • Journal article
    Irvine EA, Hoskins BJ, Shine KP, 2014,

    A simple framework for assessing the trade-off between the climate impact of aviation carbon dioxide emissions and contrails for a single flight

    , ENVIRONMENTAL RESEARCH LETTERS, Vol: 9, ISSN: 1748-9326
  • Journal article
    De Kauwe MG, Medlyn BE, Zaehle S, Walker AP, Dietze MC, Wang Y-P, Luo Y, Jain AK, El-Masri B, Hickler T, Warlind D, Weng E, Parton WJ, Thornton PE, Wang S, Prentice IC, Asao S, Smith B, McCarthy HR, Iversen CM, Hanson PJ, Warren JM, Oren R, Norby RJet al., 2014,

    Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites

    , NEW PHYTOLOGIST, Vol: 203, Pages: 883-899, ISSN: 0028-646X

    Elevated atmospheric CO2concentration (eCO2) has the potential to increase vegetationcarbon storage if increased net primary production causes increased long-lived biomass.Model predictions of eCO2effects on vegetation carbon storage depend on how allocationand turnover processes are represented. We used data from two temperate forest free-air CO2enrichment (FACE) experiments toevaluate representations of allocation and turnover in 11 ecosystem models. Observed eCO2effects on allocation were dynamic. Allocation schemes based on func-tional relationships among biomass fractions that vary with resource availability were best ableto capture the general features of the observations. Allocation schemes based on constantfractions or resource limitations performed less well, with some models having unintendedoutcomes. Few models represent turnover processes mechanistically and there was wide vari-ation in predictions of tissue lifespan. Consequently, models did not perform well at predictingeCO2effects on vegetation carbon storage. Our recommendations to reduce uncertainty include: use of allocation schemes constrainedby biomass fractions; careful testing of allocation schemes; and synthesis of allocation andturnover data in terms of model parameters. Data from intensively studied ecosystem manip-ulation experiments are invaluable for constraining models and we recommend that suchexperiments should attempt to fully quantify carbon, water and nutrient budgets.
  • Journal article
    MacKenzie RCI, Goeritz A, Greedy S, von Hauff E, Nelson Jet al., 2014,

    Theory of Stark spectroscopy transients from thin film organic semiconducting devices

    , PHYSICAL REVIEW B, Vol: 89, ISSN: 2469-9950
  • Journal article
    Thuburn J, Cotter CJ, Dubos T, 2014,

    A mimetic, semi-implicit, forward-in-time, finite volume shallow water model: comparison of hexagonal–icosahedral and cubed-sphere grids

    , Geoscientific Model Development, Vol: 7, Pages: 909-929
  • Journal article
    Tariq F, Yufit V, Eastwood DS, Merla Y, Biton M, Wu B, Chen Z, Freedman K, Offer GJ, Peled E, Lee PD, Golodnitsky D, Brandon NPet al., 2014,

    In-Operando X-ray Tomography Study of Lithiation Induced Delamination of Si Based Anodes for Lithium-Ion Batteries

    , Electrochemistry Letters, Vol: 3

    Silicon-Lithium based rechargeable batteries offer high gravimetric capacity. However cycle life and electrode microstructure failure mechanisms remain poorly understood. Here we present an X-ray tomography method to investigate in-operando lithiation induced stress cracking leading to the delamination of a composite Si based electrode. Simultaneous voltage measurements show increased cell resistance correlating with severe delamination and microstructural changes. 3D analysis revealed 44.1% loss of the initial electrode-current collector area after 1 hour of operation at 2.4 mA/cm2 and a 21.2% increase in new anode surface area. The work represents a new basis for future investigation of Si based anodes.
  • Journal article
    Wu B, Parkes MP, Yufit V, De Benedetti L, Veismann S, Wirsching C, Vesper F, Martinez-Botas RF, Marquis AJ, Offer GJ, Brandon NPet al., 2014,

    Design and testing of a 9.5 kWe proton exchange membrane fuel cell-supercapacitor passive hybrid system

    , International Journal of Hydrogen Energy, Vol: 39, Pages: 7885-7896, ISSN: 0360-3199

    The design and test of a 9.5 kWe proton exchange membrane fuel cell passively coupled with a 33 × 1500 F supercapacitor pack is presented. Experimental results showed that the system reduced dynamic loads on the fuel cell without the need for additional DC/DC converters. Fuel efficiency gains of approximately 5% were achieved by passive hybridisation in addition to addressing two main operational degradation mechanisms: no-load idling and rapid load cycling.Electrochemical Impedance Spectroscopy measurements indicated that the supercapacitor capacitance dropped with decreasing cell voltage and suggested that operation below 1.3 V is not recommended. Knee-frequency measurements suggested little benefit was gained in using passive systems with load cycles that have frequency components above 0.19 Hz. Analysis of system sizing suggested using the minimum number of supercapacitors to match the open circuit voltage of the fuel cell to maximise load buffering.
  • Journal article
    Hill J, Popova EE, Ham DA, Piggott MD, Srokosz Met al., 2014,

    Adapting to life: ocean biogeochemical modelling and adaptive remeshing

    , Ocean Science, Vol: 10, Pages: 323-343

    An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in vertical nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a simple vertical column (quasi-1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2–3. Unlike previous work the adaptivity metric used is flexible and we show that capturing the physical behaviour of the model is paramount to achieving a reasonable solution. Adding biological quantities to the adaptivity metric further refines the solution. We then show the potential of this method in two case studies where we change the adaptivity metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate that adaptive meshes may provide a suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high vertical resolution whilst minimising the number of elements in the mesh. M
  • Journal article
    Kokoni S, Skea J, 2014,

    Input-output and life-cycle emissions accounting: applications in the real world

    , CLIMATE POLICY, Vol: 14, Pages: 372-396, ISSN: 1469-3062
  • Journal article
    Pfeifer M, Lefebvre V, Gardner TA, Arroyo-Rodriguez V, Baeten L, Banks-Leite C, Barlow J, Betts MG, Brunet J, Cerezo A, Cisneros LM, Collard S, D'Cruze N, da Silva Motta C, Duguay S, Eggermont H, Eigenbrod F, Hadley AS, Hanson TR, Hawes JE, Scalley TH, Klingbeil BT, Kolb A, Kormann U, Kumar S, Lachat T, Lakeman Fraser P, Lantschner V, Laurance WF, Leal IR, Lens L, Marsh CJ, Medina-Rangel GF, Melles S, Mezger D, Oldekop JA, Overal WL, Owen C, Peres CA, Phalan B, Pidgeon AM, Pilia O, Possingham HP, Possingham ML, Raheem DC, Ribeiro DB, Ribeiro Neto JD, Robinson WD, Robinson R, Rytwinski T, Scherber C, Slade EM, Somarriba E, Stouffer PC, Struebig MJ, Tylianakis JM, Tscharntke T, Tyre AJ, Urbina-Cardona JN, Vasconcelos HL, Wearn O, Wells K, Willig MR, Wood E, Young RP, Bradley AV, Ewers RMet al., 2014,

    BIOFRAG - a new database for analyzing BIOdiversity responses to forest FRAGmentation

    , Ecology and Evolution, Vol: 4, Pages: 1524-1537, ISSN: 2045-7758
  • Journal article
    Walker AP, Hanson PJ, De Kauwe MG, Medlyn BE, Zaehle S, Asao S, Dietze M, Hickler T, Huntingford C, Iversen CM, Jain A, Lomas M, Luo Y, McCarthy H, Parton WJ, Prentice IC, Thornton PE, Wang S, Wang Y-P, Warlind D, Weng E, Warren JM, Woodward FI, Oren R, Norby RJet al., 2014,

    Comprehensive ecosystem model-data synthesis using multiple data sets at two temperate forest free-air CO2 enrichment experiments: Model performance at ambient CO2 concentration

    , Journal of Geophysical Research: Biogeosciences, Vol: 119, Pages: 937-964, ISSN: 2169-8961

    Free‐air CO2 enrichment (FACE) experiments provide a remarkable wealth of data which can be used to evaluate and improve terrestrial ecosystem models (TEMs). In the FACE model‐data synthesis project, 11 TEMs were applied to two decadelong FACE experiments in temperate forests of the southeastern U.S.—the evergreen Duke Forest and the deciduous Oak Ridge Forest. In this baseline paper, we demonstrate our approach to model‐data synthesis by evaluating the models' ability to reproduce observed net primary productivity (NPP), transpiration, and leaf area index (LAI) in ambient CO2 treatments. Model outputs were compared against observations using a range of goodness‐of‐fit statistics. Many models simulated annual NPP and transpiration within observed uncertainty. We demonstrate, however, that high goodness‐of‐fit values do not necessarily indicate a successful model, because simulation accuracy may be achieved through compensating biases in component variables. For example, transpiration accuracy was sometimes achieved with compensating biases in leaf area index and transpiration per unit leaf area. Our approach to model‐data synthesis therefore goes beyond goodness‐of‐fit to investigate the success of alternative representations of component processes. Here we demonstrate this approach by comparing competing model hypotheses determining peak LAI. Of three alternative hypotheses—(1) optimization to maximize carbon export, (2) increasing specific leaf area with canopy depth, and (3) the pipe model—the pipe model produced peak LAI closest to the observations. This example illustrates how data sets from intensive field experiments such as FACE can be used to reduce model uncertainty despite compensating biases by evaluating individual model assumptions.
  • Journal article
    Goode AE, Hine NDM, Chen S, Bergin SD, Shaffer MSP, Ryan MP, Haynes PD, Porter AE, McComb DWet al.,

    Mapping functional groups on oxidised multi-walled carbon nanotubes at the nanometre scale

    , Chemical Communications, ISSN: 1364-548X
  • Report
    McDowall W, Francis L, Staffell I, Grünewald P, Kansara T, Ekins P, Dodds P, Hawkes AD, Agnolucci Pet al., 2014,

    The role of fuel cells and hydrogen in providing affordable, secure and low carbon heat

    , London, UK
  • Journal article
    Pfenninger S, Hawkes A, Keirstead J, 2014,

    Energy systems modeling for twenty-first century energy challenges

    , Renewable and Sustainable Energy Reviews, Vol: 33, Pages: 74-86, ISSN: 1364-0321

    Energy systems models are important methods used to generate a range of insight and analysis on the supply and demand of energy. Developed over the second half of the twentieth century, they are now seeing increased relevance in the face of stringent climate policy, energy security and economic development concerns, and increasing challenges due to the changing nature of the twenty-first century energy system. In this paper, we look particularly at models relevant to national and international energy policy, grouping them into four categories: energy systems optimization models, energy systems simulation models, power systems and electricity market models, and qualitative and mixed-methods scenarios. We examine four challenges they face and the efforts being taken to address them: (1) resolving time and space, (2) balancing uncertainty and transparency, (3) addressing the growing complexity of the energy system, and (4) integrating human behavior and social risks and opportunities. In discussing these challenges, we present possible avenues for future research and make recommendations to ensure the continued relevance for energy systems models as important sources of information for policy-making.
  • Journal article
    Chakrabarti MH, Brandon NP, Hajimolana SA, Tariq E, Yufit V, Hashim MA, Hussain MA, Low CTJ, Aravind PVet al., 2014,

    Application of carbon materials in redox flow batteries

    , JOURNAL OF POWER SOURCES, Vol: 253, Pages: 150-166, ISSN: 0378-7753
  • Journal article
    Beelen R, Stafoggia M, Raaschou-Nielsen O, Andersen ZJ, Xun WW, Katsouyanni K, Dimakopoulou K, Brunekreef B, Weinmayr G, Hoffmann B, Wolf K, Samoli E, Houthuijs D, Nieuwenhuijsen M, Oudin A, Forsberg B, Olsson D, Salomaa V, Lanki T, Yli-Tuomi T, Oftedal B, Aamodt G, Nafstad P, De Faire U, Pedersen NL, Ostenson C-G, Fratiglioni L, Penell J, Korek M, Pyko A, Eriksen KT, Tjonneland A, Becker T, Eeftens M, Bots M, Meliefste K, Wang M, Bueno-de-Mesquita B, Sugiri D, Kraemer U, Heinrich J, de Hoogh K, Key T, Peters A, Cyrys J, Concin H, Nagel G, Ineichen A, Schaffner E, Probst-Hensch N, Dratva J, Ducret-Stich R, Vilier A, Clavel-Chapelon F, Stempfelet M, Grioni S, Krogh V, Tsai M-Y, Marcon A, Ricceri F, Sacerdote C, Galassi C, Migliore E, Ranzi A, Cesaroni G, Badaloni C, Forastiere F, Tamayo I, Amiano P, Dorronsoro M, Katsoulis M, Trichopoulou A, Vineis P, Hoek Get al., 2014,

    Long-term Exposure to Air Pollution and Cardiovascular Mortality <i>An Analysis of 22 European Cohorts</i>

    , EPIDEMIOLOGY, Vol: 25, Pages: 368-378, ISSN: 1044-3983
  • Journal article
    Zaehle S, Medlyn BE, De Kauwe MG, Walker AP, Dietze MC, Hickler T, Luo Y, Wang Y-P, El-Masri B, Thornton P, Jain A, Wang S, Warlind D, Weng E, Parton W, Iversen CM, Gallet-Budynek A, McCarthy H, Finzi AC, Hanson PJ, Prentice IC, Oren R, Norby RJet al., 2014,

    Evaluation of 11 terrestrial carbon-nitrogen cycle models against observations from two temperate Free-Air CO<sub>2</sub> Enrichment studies

    , NEW PHYTOLOGIST, Vol: 202, Pages: 803-822, ISSN: 0028-646X
  • Journal article
    Green R, Staffell I, Vasilakos N, 2014,

    Divide and Conquer? <i>k</i>-Means Clustering of Demand Data Allows Rapid and Accurate Simulations of the British Electricity System

    , IEEE TRANSACTIONS ON ENGINEERING MANAGEMENT, Vol: 61, Pages: 251-260, ISSN: 0018-9391
  • Journal article
    Madani K, Read L, Shalikarian L, 2014,

    Voting Under Uncertainty: A Stochastic Framework for Analyzing Group Decision Making Problems

    , WATER RESOURCES MANAGEMENT, Vol: 28, Pages: 1839-1856, ISSN: 0920-4741
  • Journal article
    Winskel M, Radcliffe J, Skea J, Wang Xet al., 2014,

    Remaking the UK's energy technology innovation system: From the margins to the mainstream

    , ENERGY POLICY, Vol: 68, Pages: 591-602, ISSN: 0301-4215
  • Journal article
    Saini PK, Romain C, Williams CK, 2014,

    Dinuclear metal catalysts: improved performance of heterodinuclear mixed catalysts for CO2-epoxide copolymerization

    , Chemical Communications, Vol: 50, Pages: 4164-4167, ISSN: 1364-548X

    Some of the most active catalysts for carbon dioxide and epoxide copolymerization are dinuclear metal complexes. Whilst efficient homodinuclear catalysts are known, until now heterodinuclear catalysts remain unreported. Here, a facile, in situ route to a catalyst system comprising a mixture of homo- and heteronuclear Zn–Mg complexes is presented. This catalyst system shows excellent polymerization control and exhibits significantly higher activity than the homodinuclear catalysts alone or in combination.
  • Journal article
    Few S, Frost JM, Kirkpatrick J, Nelson Jet al., 2014,

    Influence of Chemical Structure on the Charge Transfer State Spectrum of a Polymer:Fullerene Complex

    , JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 118, Pages: 8253-8261, ISSN: 1932-7447

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