Academic publications

<jats:title>Abstract</jats:title><jats:p>Ecosystem respiration is a primary component of the carbon cycle and understanding the mechanisms that determine its temperature dependence will be important for predicting how rates of carbon efflux might respond to global warming. We used a rare model system, comprising a network of geothermally heated streams ranging in temperature from 5 °C to 25 °C, to explore the nature of the relationship between respiration and temperature. Using this ‘natural experiment’, we tested whether the natal thermal regime of stream communities influenced the temperature dependence of respiration in the absence of other potentially confounding variables. An empirical survey of 13 streams across the thermal gradient revealed that the temperature dependence of whole‐stream respiration was equivalent to the average activation energy of the respiratory complex (0.6–0.7 eV). This observation was also consistent for <jats:italic>in‐situ</jats:italic> benthic respiration. Laboratory experiments, incubating biofilms from four streams across the thermal gradient at a range of temperatures, revealed that the activation energy and Q<jats:sub>10</jats:sub> of respiration were remarkably consistent across streams, despite marked differences in their thermal history and significant turnover in species composition. Furthermore, absolute rates of respiration at standardised temperature were also unrelated to ambient stream temperature, but strongly reflected differences in biofilm biomass. Together, our results suggest that the core biochemistry, which drives the kinetics of oxidative respiratory metabolism, may be well conserved among diverse taxa and environments, and that the intrinsic sensitivity of respiration to temperature is not influenced by ambient environmental temperature.</jats:p>

Journal article

Pahnke K, van de Flierdt T, Jones KM, Lambelet M, Hemming SR, Goldstein SLet al., 2012,

GEOTRACES intercalibration of neodymium isotopes and rare earth element concentrations in seawater and suspended particles. Part 2: Systematic tests and baseline profiles

, LIMNOLOGY AND OCEANOGRAPHY-METHODS, Vol: 10, Pages: 252-269, ISSN: 1541-5856

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Citations: 45

Journal article

van de Flierdt T, Pahnke K, Amakawa H, Andersson P, Basak C, Coles B, Colin C, Crocket K, Frank M, Frank N, Goldstein SL, Goswami V, Haley BA, Hathorne EC, Hemming SR, Henderson GM, Jeandel C, Jones K, Kreissig K, Lacan F, Lambelet M, Martin EE, Newkirk DR, Obata H, Pena L, Piotrowski AM, Pradoux C, Scher HD, Schoberg H, Singh SK, Stichel T, Tazoe H, Vance D, Yang Jet al., 2012,

GEOTRACES intercalibration of neodymium isotopes and rare earth element concentrations in seawater and suspended particles. Part 1: reproducibility of results for the international intercomparison

, LIMNOLOGY AND OCEANOGRAPHY-METHODS, Vol: 10, Pages: 234-251, ISSN: 1541-5856

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Citations: 107

Conference paper

Keirstead JE, Samsatli NJ, Pantaleo AM, Shah Net al., 2012,

Evaluating biomass energy strategies for a UK eco-town with an MILP optimization model

, Pages: 306-316

Recent years have shown a marked interest in the construction of eco-towns, showcase developments intended to demonstrate the best in ecologically-sensitive and energy-efficient construction. This paper examines one such development in the UK and considers the role of biomass energy systems. We present an integrated resource modelling framework that identifies an optimized low-cost energy supply system including the choice of conversion technologies, fuel sources, and distribution networks. Our analysis shows that strategies based on imported wood chips, rather than locally converted forestry residues, burned in a mix of ICE and ORC combined heat and power facilities offer the most promise. While there are uncertainties surrounding the precise environmental impacts of these solutions, it is clear that such biomass systems can help eco-towns to meet their target of an 80% reduction in greenhouse gas emissions.

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Conference paper

Hubbard SM, Haaf MP, Williams CK, Bakewell CMet al., 2012,

Isotactic polylactic acid (PLA) formation with chiral aluminum hydroxyquinolate catalysts

, 11th International Biorelated Polymer Symposium / 243rd National Spring Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Naro YR, Haaf MP, Williams CK, Bakewell CMet al., 2012,

Zinc quinolide catalysts for the stereoselective polymerization of lactide

, 11th International Biorelated Polymer Symposium / 243rd National Spring Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Journal article

Emmott CJM, Urbina A, Nelson J, 2012,

Environmental and economic assessment of ITO-free electrodes for organic solar cells

, Solar Energy Materials and Solar Cells, Vol: 97, Pages: 14-21, ISSN: 0927-0248

Journal article

Didham RK, Kapos V, Ewers RM, 2012,

Rethinking the conceptual foundations of habitat fragmentation research

, OIKOS, Vol: 121, Pages: 161-170, ISSN: 0030-1299

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Citations: 242

Journal article

Horie M, Kettle J, Yu C-Y, Majewski LA, Chang S-W, Kirkpatrick J, Tuladhar SM, Nelson J, Saunders BR, Turner MLet al., 2012,

Cyclopentadithiophene-benzothiadiazole oligomers and polymers; synthesis, characterisation, field-effect transistor and photovoltaic characteristics

, JOURNAL OF MATERIALS CHEMISTRY, Vol: 22, Pages: 381-389, ISSN: 0959-9428

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Citations: 59

Journal article

Faist MA, Kirchartz T, Gong W, Ashraf RS, McCulloch I, de Mello JC, Ekins-Daukes NJ, Bradley DDC, Nelson Jet al., 2012,

Competition between the Charge Transfer State and the Singlet States of Donor or Acceptor Limiting the Efficiency in Polymer:Fullerene Solar Cells

, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 685-692, ISSN: 0002-7863

Conference paper

Zolgafhari A, Sivakumar A, Polak JW, 2012,

Choice set pruning in residential location choice modelling: a comparison of sampling and choice set generation approaches in greater London

, 43rd Annual Conference of the Universities-Transport-Studies-Group (UTSG), Publisher: TAYLOR & FRANCIS LTD, Pages: 87-106, ISSN: 0308-1060

The discrete choice analysis of residential location choice forms an important part of land use-transport modelling systems but gives rise to a number of significant modelling

Journal article

Dhanirama D, Gronow J, Voulvoulis N, 2012,

Cosmetics as a potential source of environmental contamination in the UK

, Environmental Technology, Vol: 33, Pages: 1597-1608, ISSN: 0959-3330

Journal article

Buytaert W, 2012,

Assessment of impacts of climate change on mountain hydrology: Development methodology based on situation-th example of the Peruvian Andes (Assessment of the Impacts of Climate Change on Mountain Hydrology: Development of a Methodology Through a Case Study in the Andes of Peru)

, Mountain Research and Development, Vol: 32, Pages: 143-144, ISSN: 0276-4741

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Journal article

Xia R, Al-Hashimi M, Tsoi WC, Heeney M, Bradley DDC, Nelson Jet al., 2012,

Fused pyrrolo[3,2-<i>d</i>:4,5-<i>d</i>′]bisthiazole-containing polymers for using in high-performance organic bulk heterojunction solar cells

, SOLAR ENERGY MATERIALS AND SOLAR CELLS, Vol: 96, Pages: 112-116, ISSN: 0927-0248

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Citations: 16

Journal article

Flatt RJ, Roussel N, Cheeseman CR, 2012,

Concrete: An eco material that needs to be improved

, Journal of the European Ceramic Society, Vol: 32, Pages: 2787-2798, ISSN: 1873-619X

Concrete is the largest volume material used by man and is irreplaceable for innumerable large infrastructure developments. From the point of view of natural resources, ecology and economy, it is virtually impossible to imagine substituting concrete by any other material. However, because of the large volumes used, its total energy and CO2 footprint is important. This material therefore needs to be improved and small steps can have a big impact, once again because of the large volumes involved. This review paper examines some of the routes that may be followed to further improve the environmental performance of concrete.

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Journal article

Howe C, Obgenova O, Milner-Gulland EJ, 2012,

Evaluating the effectiveness of a public awareness campaign as a conservation intervention: The saiga antelope Saiga tatarica in Kalmykia, Russia

, ORYX, Vol: 46, Pages: 269-277

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Journal article

Lira PK, Ewers RM, Banks-Leite C, Pardini R, Metzger JPet al., 2012,

Evaluating the legacy of landscape history: extinction debt and species credit in bird and small mammal assemblages in the Brazilian Atlantic Forest

, Journal of Applied Ecology, Pages: 1325-1333

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Journal article

Lutz T, MacLachlan A, Sudlow A, Nelson J, Hill MS, Molloy KC, Haque SAet al., 2012,

Thermal decomposition of solution processable metal xanthates on mesoporous titanium dioxide films: a new route to quantum-dot sensitised heterojunctions

, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 14, Pages: 16192-16196, ISSN: 1463-9076

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Citations: 26

Journal article

Hill J, Piggott MD, Ham DA, Popova EE, Srokosz MA, Hill J, Piggott M, Ham D, Popova E, Srokosz M, Hill J, Ham DA, Piggott MD, 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.

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Journal article

Wang L, Ochoa-Rodriguez S, Simoes N, Onof C, Maksimović Čet al., 2012,

Radar-raingauge data combination techniques: a revision and analysis of their suitability for urban hydrology

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Journal article

Chaudry M, Skea J, Wang X, Jenkins Net al., 2012,

Modelling UK energy system response to natural gas supply infrastructure failures

, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY, Vol: 226, Pages: 501-513, ISSN: 0957-6509

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Citations: 5

Journal article

Niedermeyer H, Hallett JP, Villar-Garcia IJ, Hunt PA, Welton Tet al., 2012,

Mixtures of ionic liquids

, CHEMICAL SOCIETY REVIEWS, Vol: 41, Pages: 7780-7802, ISSN: 0306-0012

Journal article

Zolfaghari A, Sivakumar A, Polak JW, 2012,

Choice set pruning in residentiallocation choice modelling: acomparison of sampling and choiceset generation approaches in greaterLondon

, Transportation Planning and Technology, Vol: 1, Pages: 87-106

The discrete choice analysis of residential location choice forms an important part of land use-transport modelling systems but gives rise to a number of significant modelling challenges, one of which is the choice set formation problem. A number of alternative approaches exist to addressing the choice set formation problem,but to the best of our knowledge, there have been no efforts to empirically compare their performance using real choice data. In this paper, we propose to address this gap by examining the performance of several choice set formation methods within the context of residential location choice in London. The paperpresents a brief review of the relevant theoretical and empirical literature on thetreatment of the choice set formation problem in the context of spatial choice and sets out the characteristics of the specific modelling approaches implemented in the empirical research. In particular, we compare a recently proposed hazard-based screening model with more conventional pure statistical treatments. Theempirical research uses a specially constructed data-set on residential location choice, developed by the authors for the Greater London area, which draws on information from a number of separate data sources (including revealed preference data from the London Area Travel Survey). The alternative choice set formation approaches are assessed in terms of their prediction performance on a hold-out validation sub-sample and also in terms of estimated modelparameters.

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Journal article

Sivakumar A, Keirstead J, Polak JW, 2012,

Integrated Modelling of the Demand & Supply Vectors in Urban Energy Systems: Conceptual and Modelling Frameworks for the Development of a New Toolkit

, Computer-Aided Civil and Infrastructure Engineering

This paper presents the conceptual and modelling frameworks underlying the development of SynCity, an urban systems modelling tool developed as part of the BP-sponsored Urban Energy Systems (UES) project at Imperial College London. SynCity, a hierarchical model system developed in Java, comprises four layers – a spatial layout model, an agent-based microsimulation model of urban activities (AMMUA), a resource flow and conversion/network optimisation model; and an urban energy service networks model. The AMMUA comprises three inter-related modules -- an activity travel demand model, an urban freight logistics component, and a land use module – and simulates a variety of agents including individuals, households, businesses, and industries. While the spatial layout and resource flow models are optimization models aimed at producing normative and potentially optimal solutions, the AMMUA is a descriptive model that aims to predict realistic patterns of agent behaviour. This combination forms a novel approach to modelling urban energy systems which is, to the best of our knowledge, among the first of its kind (this approach has some precedent in continuous equilibrium network design models). The complexity of integrated systems modelling does not typically allow for normative models and our approach conceptually overcomes the difficulty, thus simultaneously serving as a descriptor of behaviour and a design tool. The implementation of SynCity described in this paper is not only the first empirical application of an activity-based travel demand system in the UK but goes further to tie activity and travel demand patterns to resource consumption and energy demand. More importantly, the research breaks new ground in the way that transport demand is conceptualised – as part of a wider system of interactive social and economic relationships that are examined both from a normative and descriptive perspective.

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Journal article

Howe C, Milner-Gulland EJ, 2012,

Evaluating indices of conservation success: A comparative analysis of outcome- and output-based indices

, Animal Conservation, Vol: 15, Pages: 217-226, ISSN: 1367-9430

Conservation funders require methods by which to evaluate the relative success of projects within their portfolios. One approach is to develop robust indices of success that are consistent between projects and evaluators. We used three contrasting indices to evaluate factors contributing to success of projects funded by the UK Government's Darwin Initiative. The indices were: Darwin Outputs (related to the Darwin Initiative's own method of evaluating the success of the projects it supports), Impact Assessment (based on the method developed by Mace et al. for evaluating the success of projects supported by zoos) and a Ranked Outcomes (a qualitatively ranked outcome index). We evaluated the internal consistency of the indices by comparing the assessments of multiple independent scorers. We assessed their robustness by checking for differences between indices and assessors in the success level assigned to a given project. We then used mixed effects models to analyse the factors contributing to project success, as expressed by each index, and compared the factors highlighted as important by each index. Although there were systematic differences between scorers, relative rankings between scorers were consistent. The indices were in fair agreement as to project success ranks, although the success ranks assigned by subjective ranked outcome- and output-based indices were more consistent between assessors than the impact assessment index. Higher levels of funding led to projects receiving consistently higher success scores. Other variables varied in their importance between indices, although metrics of education were consistently important. This study shows that it is possible to develop robust outcome-based indices of conservation success for comparison of projects within a funder's portfolio, although the nuances picked up by different indices suggest a need for multiple indices to capture different facets of success. We also highlight the need for thorough testing

Journal article

Rodriguez J, Mac Dowell N, Llovell F, Adjiman CS, Jackson G, Galindo Aet al., 2012,

Modelling the fluid phase behaviour of aqueous mixtures of multifunctional alkanolamines and carbon dioxide using transferable parameters with the SAFT-VR approach

, MOLECULAR PHYSICS, Vol: 110, Pages: 1325-1348, ISSN: 0026-8976

Journal article

Banks-Leite C, Ewers RM, Metzger JP, 2012,

Unravelling the drivers of community dissimilarity and species extinction in fragmented landscapes

, ECOLOGY, Vol: 93, Pages: 2560-2569

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Isotactic polylactic acid (PLA) formation with chiral aluminum hydroxyquinolate catalysts

Zinc quinolide catalysts for the stereoselective polymerization of lactide

Assessment of impacts of climate change on mountain hydrology: Development methodology based on situation-th example of the Peruvian Andes (Assessment of the Impacts of Climate Change on Mountain Hydrology: Development of a Methodology Through a Case Study in the Andes of Peru)

Evaluating the effectiveness of a public awareness campaign as a conservation intervention: The saiga antelope Saiga tatarica in Kalmykia, Russia

Evaluating the legacy of landscape history: extinction debt and species credit in bird and small mammal assemblages in the Brazilian Atlantic Forest

Radar-raingauge data combination techniques: a revision and analysis of their suitability for urban hydrology

Choice set pruning in residentiallocation choice modelling: acomparison of sampling and choiceset generation approaches in greaterLondon

Integrated Modelling of the Demand & Supply Vectors in Urban Energy Systems: Conceptual and Modelling Frameworks for the Development of a New Toolkit