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  • Conference paper
    Menke R, Abraham E, Parpas P, Stoianov Iet al., 2015,

    Approximation of System Components for Pump Scheduling Optimisation

    , Proc. 13th Int. Conference on Computing and Control in the Water Industry (CCWI), Publisher: Elsevier, Pages: 1059-1068, ISSN: 1877-7058

    The operation of pump systems in water distribution systems (WDS) is commonly the most expensive task for utilities with upto 70% of the operating cost of a pump system attributed to electricity consumption. Optimisation of pump scheduling could save10-20% by improving efficiency or shifting consumption to periods with low tariffs.Due to the complexity of the optimal control problem, heuristic methods which cannot guarantee optimality are often applied.To facilitate the use of mathematical optimisation this paper investigates formulations of WDS components. We show that linearapproximations outperform non-linear approximations, while maintaining comparable levels of accuracy.

  • Journal article
    Bruce C, Madani K, 2015,

    Successful Collaborative Negotiation over Water Policy: Substance versus Process

    , JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT, Vol: 141, ISSN: 0733-9496
  • Conference paper
    Wright R, Abraham E, Parpas P, Stoianov Iet al., 2015,

    Optimized Control of Pressure Reducing Valves in Water Distribution Networks With Dynamic Topology

    , Publisher: Procedia Engineering, Elsevier
  • Journal article
    Karpouzoglou T, Zulkafli Z, Grainger S, Dewulf A, Buytaert W, Hannah DMet al., 2015,

    Environmental Virtual Observatories (EVOs): Prospects for knowledge co-creation and resilience in the Information Age

    , Current Opinion in Environmental Sustainability, Vol: 18, Pages: 40-48, ISSN: 1877-3443

    Developments in technologies are shaping information access globally. This presents opportunities and challenges for understanding the role of new technologies in sustainability research. This article focuses on a suite of technologies termed Environmental Virtual Observatories (EVOs) developed for communicating observations and simulation of environmental processes. A strength of EVOs is that they are open and decentralised, thus democratising flow and ownership of information between multiple actors. However, EVOs are discussed rarely beyond their technical aspects. By evaluating the evolution of EVOs, we illustrate why it is timely to engage with policy and societal aspects as well. While first generation EVOs are primed for scientists, second generation EVOs can have broader implications for knowledge co-creation and resilience through their participatory design.

  • Journal article
    Hamed A, Madani K, Von Holle B, Wright J, Milon JW, Bossick Met al., 2015,

    How much are Floridians willing to pay for protecting sea turtles from sea level rise?

    , Environmental Management, Vol: 57, Pages: 176-188, ISSN: 0364-152X

    Sea level rise (SLR) is posing a great inundationrisk to coastal areas. Some coastal nesting species, includingsea turtle species, have experienced diminished habitat fromSLR. Contingent valuation method (CVM) was used in aneffort to assess the economic loss impacts of SLR on sea turtlenesting habitats for Florida coasts; and to elicit values of willingnessto pay (WTP) of Central Florida residents to implementcertain mitigation strategies, which would protect Florida’s eastcoast sea turtle nesting areas. Using the open-ended anddichotomous choice CVM, we sampled residents of two Floridacommunities: Cocoa Beach and Oviedo. We estimated theWTP of households from these two cities to protect sea turtlehabitat to be between $42 and $57 per year for 5 years. Additionally,we attempted to assess the impact of the both therespondents’ demographics and their perception toward varioussituations on their WTP value. Findings include a negativecorrelation between the age of a respondent and the probabilityof an individual willing to pay the hypothetical WTP amount.We found that WTP of an individual was not dependent onprior knowledge of the effects of SLR on sea turtle habitat. Thegreatest indicators of whether or not an individual was willingto pay to protect sea turtle habitat were the respondents’ perceptionregarding the trustworthiness and efficiency of theparty which will implement the conservation measures andtheir confidence in the conservation methods used. Respondentswho perceive sea turtles having an effect on their life werealso more likely to pay.

  • Journal article
    Wheeler, Deledalle F, Tokmoldin N, Kirchartz T, Nelson J, Durrant Jet al., 2015,

    Influence of Surface Recombination on Charge-Carrier Kinetics in Organic Bulk Heterojunction Solar Cells with Nickel Oxide Interlayers

    , Physical review applied, Vol: 4, ISSN: 2331-7019

    The choice of electrode for organic photovoltaics is known to be of importance to both device stability and performance, especially regarding the open-circuit voltage (VOC). Here we show that the work function of a nickel oxide anode, varied using an O2 plasma treatment, has a considerable influence on the open-circuit voltage VOC of an organic solar cell. We probe recombination in the devices using transient photovoltage and charge extraction to determine the lifetime as a function of charge-carrier concentration and compare the experimental results with numerical drift-diffusion simulations. This combination of experiment and simulations allows us to conclude that the variations in VOC are due to a change in surface recombination, localized at the NiO anode, although only a small change in carrier lifetime is observed.

  • Conference paper
    Mawhood RK, Gazis E, Hoefnagels R, De Jong S, Slade Ret al., 2015,

    Technological and commercial maturity of aviation biofuels: Emerging options to produce jet from lignocellulosic biomass

    , 14th International Conference on Sustainable Energy Technologies (SET 2015)

    The aviation sector is responsible for an increasing share of anthropogenic CO2 emissions. Wider adoption of aviation biofuels (biojet) is imperative for the reduction of greenhouse-gas emissions, however it represents a radical departure from the existing technological regime of petroleum-based fuels. Further market deployment will require significant techno-economic breakthroughs, as well as adaptation of the existing supply chains and infrastructure.Although a large number of technologies which have the capability to produce such fuels are being developed, many of these are unlikely to be suitable for EU-based production in the short-term. Biojet production pathways vary considerably in terms of their techno-economic features, with the most highly developed being in the very early stages of commercialisation.In this article, the authors map current development and manufacturing efforts within five emerging biojet technological pathways. The research draws upon a comprehensive review of the international academic and grey literature in order to characterise the pathways according to their technological and commercial maturity, as well as progress towards international certification.By implementing the Fuel Readiness Level (FRL) methodology, the authors provide insights regarding not only the current status of the biojet sector, but also potential opportunities for the short-term development of supply chains in the EU.

  • Journal article
    Baran D, Vezie MS, Gasparini N, Deledalle F, Yao J, Schroeder BC, Bronstein H, Ameri T, Kirchartz T, McCulloch I, Nelson J, Brabec CJet al., 2015,

    Role of Polymer Fractionation in Energetic Losses and Charge Carrier Lifetimes of Polymer: Fullerene Solar Cells

    , JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 119, Pages: 19668-19673, ISSN: 1932-7447
  • Journal article
    Osipov S, Stenchikov G, Brindley H, Banks Jet al., 2015,

    Diurnal cycle of the dust instantaneous direct radiative forcing over the Arabian Peninsula

    , Atmospheric Chemistry and Physics, Vol: 15, Pages: 9537-9553, ISSN: 1680-7324

    In this study we attempted to better quantify radiative effects of dust over the Arabian Peninsula and their dependence on input parameters. For this purpose we have developed a stand-alone column radiation transport model coupled with the Mie, T-matrix and geometric optics calculations and driven by reanalysis meteorological fields and atmospheric composition. Numerical experiments were carried out for a wide range of aerosol optical depths, including extreme values developed during the dust storm on 18–20 March 2012. Comprehensive ground-based observations and satellite retrievals were used to estimate aerosol optical properties, validate calculations and carry out radiation closure. The broadband surface albedo, fluxes at the bottom and top of the atmosphere as well as instantaneous dust radiative forcing were estimated both from the model and observations. Diurnal cycle of the shortwave instantaneous dust direct radiative forcing was studied for a range of aerosol and surface characteristics representative of the Arabian Peninsula. Mechanisms and parameters responsible for diurnal variability of the radiative forcing were evaluated. We found that intrinsic variability of the surface albedo and its dependence on atmospheric conditions, along with anisotropic aerosol scattering, are mostly responsible for diurnal effects.

  • Journal article
    Moia D, Cappel UB, Leijtens T, Li X, Telford AM, Snaith HJ, O'Regan BC, Nelson J, Barnes PRFet al., 2015,

    The Role of Hole Transport between Dyes in Solid-State Dye-Sensitized Solar Cells

    , Journal of Physical Chemistry C, Vol: 119, Pages: 18975-18985, ISSN: 1932-7447
  • Journal article
    Williams CK, Paul S, Romain C, Shaw Jet al., 2015,

    Sequence selective polymerization catalysis: A new route to ABA block copoly(ester-b-carbonate-b-ester)

    , Macromolecules, Vol: 48, Pages: 6047-6056, ISSN: 0024-9297

    The preparation of ABA type block copoly(ester-b-carbonate-b-ester) from a mixture of ε-caprolactone, cyclohexene oxide, and carbon dioxide monomers and using a single catalyst is presented. By using a dinuclear zinc catalyst, both the ring-opening polymerization of ε-caprolactone and the ring-opening copolymerization of cyclohexene oxide and carbon dioxide are achieved. The catalyst shows high selectivity, activity, and control in the ring-opening copolymerization, yielding poly(cyclohexene carbonate) polyols, i.e., α,ω-dihydroxyl end-capped polycarbonates. It also functions efficiently under immortal conditions, and in particular, the addition of various equivalents of water enables the selective preparation of polyols and control over the polymers’ molecular weights and dispersities. The catalyst is also active for the ring-opening polymerization of ε-caprolactone but only in the presence of epoxide, generating α,ω-dihydroxyl-terminated polycaprolactones. It is also possible to combine the two polymerization pathways and, by controlling the chemistry of the growing polymer chain-metal end group, to direct a particular polymerization pathway. Thus, in the presence of all three monomers, the selective ring-opening copolymerization occurs to yield poly(cyclohexene carbonate). Upon removal of the carbon dioxide, the polymerization cycle switches to ring-opening polymerization and a triblock copoly(caprolactone-b-cyclohexene carbonate-b-caprolactone) is produced. The ABA type block copolymer is fully characterized, including using various spectroscopic techniques, size exclusion chromatography, and differential scanning calorimetry. The copolymers can be solvent cast to give transparent films. The copolymers show controllable glass transition temperatures from −54 to 34 °C, which are dependent on the block compositions.

  • Conference paper
    Wilson DJ, van de Flierdt T, Bridgestock LJ, Paul M, Rehkamper M, Robinson LF, Adkins JFet al., 2015,

    Exploring Pb isotopes in deep-sea corals: measurement by TIMS and application to the deglacial Southern Ocean

    , 25th Annual VM Goldschmidt Conference
  • Journal article
    Chakrabarti MH, Manan NSA, Brandon NP, Maher RC, Mjalli FS, AlNashef IM, Hajimolana SA, Hashim MA, Hussain MA, Nir Det al., 2015,

    One-pot electrochemical gram-scale synthesis of graphene using deep eutectic solvents and acetonitrile

    , CHEMICAL ENGINEERING JOURNAL, Vol: 274, Pages: 213-223, ISSN: 1385-8947
  • Journal article
    Yu W, Xu L, Graham N, Qu Jet al., 2015,

    Contribution of Fe3O4 nanoparticles to the fouling of ultrafiltration with coagulation pre-treatment

    , Scientific Reports, Vol: 5, ISSN: 2045-2322

    A coagulation (FeCl3)-ultrafiltration process was used to treat two different raw waters with/without the presence of Fe3O4 nanoparticle contaminants. The existence of Fe3O4 nanoparticles in the raw water was found to increase both irreversible and reversible membrane fouling. The trans-membrane pressure (TMP) increase was similar in the early stages of the membrane runs for both raw waters, while it increased rapidly after about 15 days in the raw water with Fe3O4 nanoparticles, suggesting the involvement of biological effects. Enhanced microbial activity with the presence of Fe3O4 nanoparticles was evident from the measured concentrations of extracellular polymeric substances (EPS) and deoxyribonucleic acid (DNA), and fluorescence intensities. It is speculated that Fe3O4 nanoparticles accumulated in the cake layer and increased bacterial growth. Associated with the bacterial growth is the production of EPS which enhances the bonding with, and between, the coagulant flocs; EPS together with smaller sizes of the nano-scale primary particles of the Fe3O4-CUF cake layer, led to the formation of a lower porosity, more resilient cake layer and membrane pore blockage.

  • Journal article
    Le Vine N, Butler A, McIntyre N, Jackson Cet al., 2015,

    Diagnosing hydrological limitations of a Land Surface Model: Application of JULES to a deep-groundwater chalk basin

    , Hydrology and Earth System Sciences Discussions, Vol: 12, Pages: 7541-7582, ISSN: 1812-2116

    Land Surface Models (LSMs) are prospective starting points to develop a global hyper-resolution model of the terrestrial water, energy and biogeochemical cycles. However, there are some fundamental limitations of LSMs related to how meaningfully hydrological fluxes and stores are represented. A diagnostic approach to model evaluation is taken here that exploits hydrological expert knowledge to detect LSM inadequacies through consideration of the major behavioural functions of a hydrological system: overall water balance, vertical water redistribution in the unsaturated zone, temporal water redistribution and spatial water redistribution over the catchment's groundwater and surface water systems. Three types of information are utilised to improve the model's hydrology: (a) observations, (b) information about expected response from regionalised data, and (c) information from an independent physics-based model. The study considers the JULES (Joint UK Land Environmental Simulator) LSM applied to a deep-groundwater chalk catchment in the UK. The diagnosed hydrological limitations and the proposed ways to address them are indicative of the challenges faced while transitioning to a global high resolution model of the water cycle.

  • Journal article
    Murphy K, Rehkämper M, Kreissig K, Coles B, van de Flierdt Tet al., 2015,

    Improvements in Cd stable isotope analysis achieved through use of liquid–liquid extraction to remove organic residues from Cd separates obtained by extraction chromatography

    , Journal of Analytical Atomic Spectrometry, Vol: 31, Pages: 319-327, ISSN: 1364-5544

    Organic compounds released from resins that are commonly employed for trace element separations are known to have a detrimental impact on the quality of isotopic analyses by MC-ICP-MS. A recent study highlighted that such effects can be particularly problematic for Cd stable isotope measurements (M. Gault-Ringold and C. H. Stirling, J. Anal. At. Spectrom., 2012, 27, 449–459). In this case, the final stage of sample purification commonly applies extraction chromatography with Eichrom TRU resin, which employs particles coated with octylphenyl-N,N-di-isobutyl carbamoylphosphine oxide (CMPO) dissolved in tri-n-butyl phosphate (TBP). During chromatography, it appears that some of these compounds are eluted alongside Cd and cannot be removed by evaporation due to their high boiling points. When aliquots of the zero-ε reference material were processed through the purification procedure, refluxed in concentrated HNO3 and analyzed at minimum dilution (in 1 ml 0.1 M HNO3), they yielded Cd isotopic compositions (ε114/110Cd = 4.6 ± 3.4, 2SD, n = 4) that differed significantly from the expected value, despite the use of a double spike technique to correct for instrumental mass fractionation. This result was accompanied by a 35% reduction in instrumental sensitivity for Cd. With increasing dilution of the organic resin residue, both of these effects are reduced and they are insignificant when the eluted Cd is dissolved in ≥3 ml 0.1 M HNO3. Our results, furthermore, indicate that the isotopic artefacts are most likely related to anomalous mass bias behavior. Previous studies have shown that perchloric acid can be effective at avoiding such effects (Gault-Ringold and Stirling, 2012; K. C. Crocket, M. Lambelet, T. van de Flierdt, M. Rehkämper and L. F. Robinson, Chem. Geol., 2014, 374–375, 128–140), presumably by oxidizing the resin-derived organics, but there are numerous disadvantages to its use. Here we show that liquid–liqui

  • Journal article
    Shevchenko IV, Berloff PS, 2015,

    Multi-layer quasi-geostrophic ocean dynamics in Eddy-resolving regimes

    , Ocean Modelling, Vol: 94, Pages: 1-14, ISSN: 1463-5011

    The multi-layer quasi-geostrophic model of the wind-driven ocean gyres is numerically investigated using a combination of long-time runs (200 years) needed for accurate statistics, spatial resolutions (grid interval of less than one kilometer) needed for accurate representation of mesoscale eddies, and large Reynolds number (Re > 104) needed for more realistic flow regimes. We gradually increased the Reynolds number by lowering the eddy viscosity and analysed the corresponding changes of the large-scale circulation, energetics and eddy fluxes, with the goal to understand how the nonlinear eddy dynamics affects the large-scale ocean circulation, as more and more degrees of freedom become dynamically available. Three- and six-layer configurations of the model are considered in order to understand effects of higher baroclinic modes. A parameter sensitivity study is also carried out to show that the explored flow regime is robust.As Re increases, most properties of the flow show no signs of approaching an asymptote, and the following tendencies are found. The time-mean flow properties tend to an asymptote in the three-layer model but not in the six-layer one, suggesting that higher baroclinic modes are dynamically more active at larger Re. The eddy kinetic and potential energies grow faster in the six-layer case. The intensity of the eddy forcing (eddy flux divergence) increases with Re. The inter-gyre eddy potential vorticity flux is predominantly northward and up-gradient for all Re studied. A comparison of the three- and six-layer model solutions revealed an inhibitory influence of high baroclinic modes on the penetration length of the eastward jet extension of the western boundary currents and on the strength of the adjacent recirculation zones. In large-Re regimes, the population of eddies is mostly sustained by the eddy generation at the eastern end of the eastward jet rather than in its central section. Finally, by studying the numerical convergence of the sol

  • Journal article
    Zhang T, Marinescu M, O'Neill L, Wild M, Offer Get al., 2015,

    Modeling the voltage loss mechanisms in lithium-sulfur cells: the importance of electrolyte resistance and precipitation kinetics.

    , Physical Chemistry Chemical Physics, Vol: 17, Pages: 22581-22586, ISSN: 1463-9084

    Understanding of the complex electrochemical, transport, and phase-change phenomena in Li-S cells requires experimental characterization in tandem with mechanistic modeling. However, existing Li-S models currently contradict some key features of experimental findings, particularly the evolution of cell resistance during discharge. We demonstrate that, by introducing a concentration-dependent electrolyte conductivity, the correct trends in voltage drop due to electrolyte resistance and activation overpotentials are retrieved. In addition, we reveal the existence of an often overlooked potential drop mechanism in the low voltage-plateau which originates from the limited rate of Li2S precipitation.

  • Journal article
    Graven HD, 2015,

    Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century

    , Proceedings of the National Academy of Sciences of the United States of America, Vol: 112, Pages: 9542-9545, ISSN: 1091-6490

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  • Journal article
    Xie C, Hawkes AD, 2015,

    Estimation of inter-fuel substitution possibilities in China's transport industry using ridge regression

    , ENERGY, Vol: 88, Pages: 260-267, ISSN: 0360-5442
  • Journal article
    Moro M, Fischer A, Milner-Gulland EJ, Lowassa A, Naiman LC, Hanley Net al., 2015,

    A stated preference investigation of household demand for illegally hunted bushmeat in the Serengeti, Tanzania

    , ANIMAL CONSERVATION, Vol: 18, Pages: 377-386, ISSN: 1367-9430
  • Journal article
    Ristic B, Madani K, Makuch Z, 2015,

    The Water Footprint of Data Centers

    , SUSTAINABILITY, Vol: 7, Pages: 11260-11284
  • Journal article
    Nuno A, Milner-Gulland EJ, Bunnefeld N, 2015,

    Detecting abundance trends under uncertainty: the influence of budget, observation error and environmental change

    , ANIMAL CONSERVATION, Vol: 18, Pages: 331-340, ISSN: 1367-9430
  • Journal article
    Plebani M, Fussmann KE, Hansen DM, O'Gorman EJ, Stewart RIA, Woodward G, Petchey OLet al., 2015,

    Substratum-dependent responses of ciliate assemblages to temperature: a natural experiment in Icelandic streams

    , FRESHWATER BIOLOGY, Vol: 60, Pages: 1561-1570, ISSN: 0046-5070
  • Journal article
    Ryder CL, McQuaid JB, Flamant C, Rosenberg PD, Washington R, Brindley HE, Highwood EJ, Marsham JH, Parker DJ, Todd MC, Banks JR, Brooke JK, Engelstaedter S, Estelles V, Formenti P, Garcia-Carreras L, Kocha C, Marenco F, Sodemann H, Allen CJT, Bourdon A, Bart M, Cavazos-Guerra C, Chevaillier S, Crosier J, Darbyshire E, Dean AR, Dorsey JR, Kent J, O'Sullivan D, Schepanski K, Szpek K, Trembath J, Woolley Aet al., 2015,

    Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

    , Atmospheric Chemistry and Physics, Vol: 15, Pages: 8479-8520, ISSN: 1680-7324

    The Fennec climate programme aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE (Service des Avions Français Instrumentés pour la Recherche en Environnement) Falcon 20 is described, with specific focus on instrumentation specially developed for and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include (1) the first airborne measurement of dust particles sizes of up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI (Spinning Enhanced Visible Infra-Red Imager) satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in situ observations of processes in SABL clouds showing dust acting as cloud condensation nuclei (CCN) and ice nuclei (IN) at −15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold pool (haboob) issued from deep convection over the Atlas Mountains, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and

  • Journal article
    Foster T, Brozović N, Butler AP, 2015,

    Why well yield matters for managing agricultural drought risk

    , Weather and Climate Extremes, Vol: 10, Pages: 11-19, ISSN: 2212-0947

    Groundwater-fed irrigation has supported growth in agricultural production around the world by allowing farmers to buffer production against the risks associated with variable and uncertain climatic conditions. However, uncontrolled exploitation has also led to rapid rates of groundwater depletion in many semi-arid and arid regions that threaten farmers' long-term capacity to adapt to future climate change and extreme events. Declining well yields, which control the potential rate and feasibility of groundwater abstraction, are likely to restrict adaptation to drought, but this interaction has largely been neglected in previous research. In this study, we present a set of numerical hydro-economic simulations that assess the joint biophysical and economic effects of climate variability and well yield on irrigated agriculture through a case study in the Texas High Plains region of the United States. Our results demonstrate that reductions in well yield will constrain farmers' ability to use irrigation as an adaptive tool, and may have large negative economic impacts on production. Significantly, economic impacts will be greatest during drought events that are projected to increase in frequency and intensity as a result of climate change. We suggest therefore that management of well yields should be a key consideration when evaluating agricultural drought risk adaptation.

  • Conference paper
    Lomberg M, Boldrin P, Tariq F, Offer G, Wu B, Brandon NPet al., 2015,

    Additive manufacturing for solid oxide cell electrode fabrication

    , ECS Conference on Electrochemical Energy Conversion & Storage with SOFC-XIV, Publisher: Electrochemical Society, Pages: 2119-2127, ISSN: 1938-6737

    Additive manufacturing can potentially offer a highly-defined electrode microstructure, as well as fast and reproducible electrode fabrication. Selective laser sintering is an additive manufacturing technique in which three-dimensional structures are created by bonding subsequent layers of powder using a laser. Although selective laser sintering can be applied to a wide range of materials, including metals and ceramics, the scientific and technical aspects of the manufacturing parameters and their impact on microstructural evolution during the process are not well understood. In the present study, a novel approach for electrode fabrication using selective laser sintering was evaluated by conducting a proof of concept study. A Ni-patterned fuel electrode was laser sintered on an yttria-stabilized zirconia substrate. The optimization process of laser parameters (laser sintering rate and laser power) and the electrochemical results of a full cell with a laser sintered electrode are presented. The challenges and prospects of using selective laser sintering for solid oxide cell fabrication are discussed.

  • Journal article
    Yao J, Kirchartz T, Vezie MS, Faist MA, Gong W, He Z, Wu H, Troughton J, Watson T, Bryant D, Nelson Jet al., 2015,

    Quantifying losses in open-circuit voltage in solution-processable solar cells

    , Physical Review Applied, Vol: 4, ISSN: 2331-7019

    The maximum open-circuit voltage of a solar cell can be evaluated in terms of its ability to emit light. We herein verify the reciprocity relation between the electroluminescence spectrum and subband-gap quantum efficiency spectrum for several photovoltaic technologies at different stages of commercial development, including inorganic, organic, and a type of methyl-ammonium lead- halide CH3NH3PbI3−xClx perovskite solar cells. Based on the detailed balance theory and reciprocity relations between light emission and light absorption, voltage losses at open circuit are quantified and assigned to specific mechanisms, namely, absorption edge broadening and nonradiative recombination. The voltage loss due to nonradiative recombination is low for inorganic solar cells (0.04–0.21 V), while for organic solar cell devices it is larger but surprisingly uniform, with values of 0.34–0.44 V for a range of material combinations. We show that, in CH3NH3PbI3−xClx perovskite solar cells that exhibit hysteresis, the loss to nonradiative recombination varies substantially with voltage scan conditions. We then show that for different solar cell technologies there is a roughly linear relation between the power conversion efficiency and the voltage loss due to nonradiative recombination.

  • Journal article
    Mukherjee S, Kumar P, Yang A, Fennell Pet al., 2015,

    Energy and exergy analysis of chemical looping combustion technology and comparison with pre-combustion and oxy-fuel combustion technologies for CO2 capture

    , Journal of Environmental Chemical Engineering, Vol: 3, Pages: 2104-2114, ISSN: 2213-3437

    Carbon dioxide (CO2) emitted from conventional coal-based power plants is a growing concern for the environment. Chemical looping combustion (CLC), pre-combustion and oxy-fuel combustion are promising CO2 capture technologies which allow clean electricity generation from coal in an integrated gasification combined cycle (IGCC) power plant. This work compares the characteristics of the above three capture technologies to those of a conventional IGCC plant without CO2 capture. CLC technology is also investigated for two different process configurations—(i) an integrated gasification combined cycle coupled with chemical looping combustion (IGCC–CLC), and (ii) coal direct chemical looping combustion (CDCLC)—using exergy analysis to exploit the complete potential of CLC. Power output, net electrical efficiency and CO2 capture efficiency are the key parameters investigated for the assessment. Flowsheet models of five different types of IGCC power plants, (four with and one without CO2 capture), were developed in the Aspen plus simulation package. The results indicate that with respect to conventional IGCC power plant, IGCC–CLC exhibited an energy penalty of 4.5%, compared with 7.1% and 9.1% for pre-combustion and oxy-fuel combustion technologies, respectively. IGCC–CLC and oxy-fuel combustion technologies achieved an overall CO2 capture rate of ∼100% whereas pre-combustion technology could capture ∼94.8%. Modification of IGCC–CLC into CDCLC tends to increase the net electrical efficiency by 4.7% while maintaining 100% CO2 capture rate. A detailed exergy analysis performed on the two CLC process configurations (IGCC–CLC and CDCLC) and conventional IGCC process demonstrates that CLC technology can be thermodynamically as efficient as a conventional IGCC process.

  • Book chapter
    Woodward G, 2015,

    Biodiversity, Ecosystem Functioning, and Services in Fresh Waters: Ecological and Evolutionary Implications of Climate Change

    , Aquatic Functional Biodiversity An Ecological and Evolutionary Perspective, Publisher: Academic Press, ISBN: 9780124170209

    An Ecological and Evolutionary Perspective Andrea Belgrano, Guy Woodward, Ute Jacob ... Remarks References Biodiversity, Ecosystem Functioning, and Services in Fresh Waters: Ecological and Evolutionary Implications of Climate Change ...

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