Search or filter publications

Filter by type:

Filter by publication type

Filter by year:



  • Showing results for:
  • Reset all filters

Search results

  • Journal article
    Rodríguez J-P, McIntyre N, Díaz-Granados2 M, Maksimovic Cet al., 2012,

    A database and model to support proactive management of sediment-related sewer blockages

    Due to increasing customer and political pressures, and more stringent environmental regulations, sediment and other blockage issues are now a high priority when assessing sewer system operational performance. Blockages caused by sediment deposits reduce sewer system reliability and demand remedial action at considerable operational cost. Consequently, procedures are required for identifying which parts of the sewer system are in most need of proactive removal of sediments. This paper presents an exceptionally long (7.5 years) and spatially detailed (9,658 grid squares – 0.03 km2 each – covering a population of nearly 7.5 million) data set obtained from a customer complaints database in Bogotá (Colombia). The sediment-related blockage data are modelled using homogeneous and non-homogeneous Poisson process models. In most of the analysed areas the inter-arrival time between blockages can be represented by the homogeneous process, but there are a considerable number of areas (up to 34%) for which there is strong evidence of non-stationarity. In most of these cases, the mean blockage rate increases over time, signifying a continual deterioration of the system despite repairs, this being particularly marked for pipe and gully pot related blockages. The physical properties of the system (mean pipe slope, diameter and pipe length) have a clear but weak influence on observed blockage rates. The Bogotá case study illustrates the potential value of customer complaints databases and formal analysis frameworks for proactive sewerage maintenance scheduling in large cities.

  • Journal article
    Chon HS, Ohandja D-G, Voulvoulis N, 2012,

    The role of sediments as a source of metals in river catchments.

    , Chemosphere, Vol: 88, Pages: 1250-1256

    Aquatic sediments are a known source of pollutants, but their impact on the quality of overlying waters is not easily quantified. Sediments are generally considered to behave as a sink for pollutants such as heavy metals in the aquatic environment, frequently acting as a source for their presence in waters, with implications for catchment management. This study aimed to calculate the contribution of sediments to metal levels in overlying waters, helping understand their role as a source of metals in river catchments. An aquivalence mass balance approach was modified to take into account both natural and anthropogenic influences and applied to assess sediment contribution in a reach of the River Yare in the UK. The rates of total metal transport from sediments to overlying waters were estimated to be 29.89gd(-1) for cadmium (Cd), 1633.39gd(-1) for lead (Pb), 8.29gd(-1) for mercury (Hg) and 357.56gd(-1) for nickel (Ni). The results from the case study demonstrated that sediments could be a significant source of metal emissions in river catchments. The calculations proposed in the paper could be useful in developing strategies for sediment management, not only to improve and/or maintain quality of sediments but also to inform the selection of measures of pollution control for the catchment.

  • Journal article
    Green RJ, 2012,

    How Denmark Manages its Wind Power

    , IAEE Energy Forum, Vol: 21, Pages: 9-11
  • Journal article
    Yvon-Durocher G, Caffrey JM, Cescatti A, Dossena M, del Giorgio P, Gasol JM, Montoya JM, Pumpanen J, Staehr PA, Trimmer M, Woodward G, Allen APet al., 2012,

    Reconciling the temperature dependence of respiration across timescales and ecosystem types.

    , Nature, Vol: 487, Pages: 472-476

    Ecosystem respiration is the biotic conversion of organic carbon to carbon dioxide by all of the organisms in an ecosystem, including both consumers and primary producers. Respiration exhibits an exponential temperature dependence at the subcellular and individual levels, but at the ecosystem level respiration can be modified by many variables including community abundance and biomass, which vary substantially among ecosystems. Despite its importance for predicting the responses of the biosphere to climate change, it is as yet unknown whether the temperature dependence of ecosystem respiration varies systematically between aquatic and terrestrial environments. Here we use the largest database of respiratory measurements yet compiled to show that the sensitivity of ecosystem respiration to seasonal changes in temperature is remarkably similar for diverse environments encompassing lakes, rivers, estuaries, the open ocean and forested and non-forested terrestrial ecosystems, with an average activation energy similar to that of the respiratory complex (approximately 0.65 electronvolts (eV)). By contrast, annual ecosystem respiration shows a substantially greater temperature dependence across aquatic (approximately 0.65 eV) versus terrestrial ecosystems (approximately 0.32 eV) that span broad geographic gradients in temperature. Using a model derived from metabolic theory, these findings can be reconciled by similarities in the biochemical kinetics of metabolism at the subcellular level, and fundamental differences in the importance of other variables besides temperature—such as primary productivity and allochthonous carbon inputs—on the structure of aquatic and terrestrial biota at the community level.

  • Journal article
    Gong W, Faist MA, Ekins-Daukes NJ, Xu Z, Bradley DDC, Nelson J, Kirchartz Tet al., 2012,

    Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells

    , PHYSICAL REVIEW B, Vol: 86, ISSN: 1098-0121
  • Journal article
    Wearn OR, Reuman DC, Ewers RM, 2012,

    Extinction Debt and Windows of Conservation Opportunity in the Brazilian Amazon

    , SCIENCE, Vol: 337, Pages: 228-232, ISSN: 0036-8075
  • Conference paper
    McIntyre N, Ballard C, Bulygina N, Carroll Z, Cluckie I, Dangerfield S, Ewen J, Geris J, Henshaw A, Jackson B, Marshall M, Pagella T, Park JS, Reynolds B, O’Connell E, O’Donnell G, Sinclair F, Solloway I, Thorne C, Wheater Het al., 2012,

    The potential for reducing flood risk through changes to rural land management: outcomes from the Flood Risk Management Research Consortium

  • Conference paper
    Bakopoulou C, Bulygina N, Butler A, McIntyre Net al., 2012,

    Sensitivity Analysis and Parameter Identifiability of the Land Surface Model JULES at the point scale in permeable catchments

  • Conference paper
    Almeida S, Bulygina N, McIntyre N, Wagener T, Buytaert Wet al., 2012,

    Predicting flows in ungauged catchments using correlated information sources

    , BHS International Hydrology Symposium
  • Journal article
    Llovell F, Marcos RM, MacDowell N, Vega LFet al., 2012,

    Modeling the Absorption of Weak Electrolytes and Acid Gases with Ionic Liquids Using the Soft-SAFT Approach

    , JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 116, Pages: 7709-7718, ISSN: 1520-6106
  • Journal article
    Sommer J, Pausch J, Brundrett MC, Dixon KW, Bidartondo MI, Gebauer Get al., 2012,

    Limited carbon and mineral nutrient gain from mycorrhizal fungi by adult Australian orchids.

    , American Journal of Botany

    • Premise of the study: In addition to autotrophic and fully mycoheterotrophic representatives, the orchid family comprises species that at maturity obtain C and N partially from fungal sources. These partial mycoheterotrophs are often associated with fungi that simultaneously form ectomycorrhizas with trees. This study investigates mycorrhizal nutrition for orchids from the southwestern Australian biodiversity hotspot.• Methods: The mycorrhizal fungi of 35 green and one achlorophyllous orchid species were analyzed using molecular methods. Nutritional mode was identified for 27 species by C and N isotope abundance analysis in comparison to non-orchids from the same habitat. As a complementary approach, (13)CO(2) pulse labeling was applied to a subset of six orchid species to measure photosynthetic capacity.• Key results: Almost all orchids associated with rhizoctonia-forming fungi. Due to much higher than expected variation within the co-occurring nonorchid reference plants, the stable isotope approach proved challenging for assigning most orchids to a specialized nutritional mode; therefore, these orchids were classified as autotrophic at maturity. The (13)CO(2) pulse labeling confirmed full autotrophy for six selected species. Nonetheless, at least three orchid species (Gastrodia lacista, Prasophyllum elatum, Corybas recurvus) were identified as nutritionally distinctive from autotrophic orchids and reference plants.• Conclusions: Despite the orchid-rich flora in southwestern Australia, partial mycoheterotrophy among these orchids is less common than in other parts of the world, most likely because most associate with saprotrophic fungi rather than ectomycorrhizal fungi.

  • Journal article
    Murray SJ, Foster PN, Prentice IC, 2012,

    Future global water resources with respect to climate change and water withdrawals as estimated by a dynamic global vegetation model

    , JOURNAL OF HYDROLOGY, Vol: 448, Pages: 14-29, ISSN: 0022-1694
  • Journal article
    Kirchofer A, Brandt AR, Krevor S, Prigiobbe V, Wilcox Jet al., 2012,

    Impact of alkalinity sources on the life-cycle efficiency of mineral carbonation technologies

    , Energy and Environmental Science
  • Journal article

    Freshwater food webs: towards a more fundamental understanding of biodiversity and community dynamics

    , Freshwater Biology, Vol: 57, Pages: 1329-1341, ISSN: 0046-5070

    <jats:title>Summary</jats:title><jats:p>1. Food webs are a powerful whole‐system way to represent the patterns of biodiversity and energy flow in a readily quantifiable framework amenable to comparative analyses. Integrated theory and data on complex trophic interactions provide useful and novel ways to study ecosystem structure, dynamics, function and stability.</jats:p><jats:p>2. Freshwater ecology has contributed considerably to the advancement of food‐web ecology. This has occurred through early application of methodological advances such as stable isotope analysis and description of some of the most detailed food webs, including Little Rock Lake and the Broadstone Stream food webs.</jats:p><jats:p>3. Freshwater food webs are often highly resolved, although the inclusion of components such as bacteria continues to be challenging. Characteristics of stream food webs appear to include high rates of omnivory and a strong role for body size as a structuring influence.</jats:p><jats:p>4. While freshwater ecology has often included landscape factors, food webs from freshwaters have most often been collected at small spatial scales. There is a need to take a landscape approach to the study of food‐web dynamics in freshwater ecosystems.</jats:p><jats:p>5. Studies of food webs that take an experimental approach or utilise natural gradients remain rare but will be vital to untangling causative relationships between changing environmental conditions and food‐web structure and dynamics.</jats:p><jats:p>6. Emerging directions in freshwater food‐web research involve integrating individual‐level variation and information on traits into food‐web studies. This is allowing a growing understanding of the ways in which food webs can be used to integrate community, evolutionary and population processes into studies of biodiversity.</jats:p><jats:p>7. A Virtual

  • Journal article
    Masato G, Hoskins BJ, Woollings TJ, 2012,

    Wave-breaking characteristics of midlatitude blocking

  • Journal article
    Hoskins B, Fonseca R, Blackburn M, Jung Tet al., 2012,

    Relaxing the Tropics to an observed' state: analysis using a simple baroclinic model

  • Journal article
    Simpson IR, Blackburn M, Haigh JD, 2012,

    A Mechanism for the Effect of Tropospheric Jet Structure on the Annular Mode-Like Response to Stratospheric Forcing

    , JOURNAL OF THE ATMOSPHERIC SCIENCES, Vol: 69, Pages: 2152-2170, ISSN: 0022-4928
  • Journal article
    Sivakumar A, Pinjari A, 2012,

    Recent advances in activity and travel pattern modelling

    , TRANSPORTATION, Vol: 39, Pages: 749-754, ISSN: 0049-4488
  • Journal article
    Tauxe L, Stickley CE, Sugisaki S, Bijl PK, Bohaty SM, Brinkhuis H, Escutia C, Flores JA, Houben AJP, Iwai M, Jimenez-Espejo FJ, McKay R, Passchier S, Pross J, Riesselman CR, Roehl U, Sangiorgi F, Welsh K, Klaus A, Fehr A, Bendle JAP, Dunbar R, Gonzalez J, Hayden T, Katsuki K, Olney MP, Pekar SF, Shrivastava PK, van de Flierdt T, Williams T, Yamane Met al., 2012,

    Chronostratigraphic framework for the IODP Expedition 318 cores from the Wilkes Land Margin: Constraints for paleoceanographic reconstruction

    , PALEOCEANOGRAPHY, Vol: 27, ISSN: 0883-8305
  • Journal article
    Yoshida M, Ekins-Daukes NJ, Farrell DJ, Phillips CCet al., 2012,

    Photon ratchet intermediate band solar cells

    , Applied Physics Letters, Vol: 100, ISSN: 1077-3118

    In this paper, we propose an innovative concept for solar power conversion—the “photon ratchet” intermediate band solar cell (IBSC)—which may increase the photovoltaicenergy conversion efficiency of IBSCs by increasing the lifetime of charge carriers in the intermediate state. The limiting efficiency calculation for this concept shows that the efficiency can be increased by introducing a fast thermal transition of carriers into a non-emissive state. At 1 sun, the introduction of a “ratchet band” results in an increase of efficiency from 46.8% to 48.5%, due to suppression of entropy generation.

  • Journal article
    Irvine EA, Hoskins BJ, Shine KP, 2012,

    The dependence of contrail formation on the weather pattern and altitude in the North Atlantic

  • Journal article
    Chan N, Young T, Brindley H, Ekins-Daukes N, Araki K, Kemmoku Y, Yamaguchi Met al., 2012,

    Validation of energy prediction method for a concentrator photovoltaic module in Toyohashi Japan

    , Progress in Photovoltaics, Pages: n/a-n/a

    III–V concentrator photovoltaic systems attain high efficiency through the use of series connected multi-junction solar cells. As these solar cells absorb over distinct bands over the solar spectrum, they have a more complex response to real illumination conditions than conventional silicon solar cells. Estimates for annual energy yield made assuming fixed reference spectra can vary by up to 15% depending on the assumptions made. Using a detailed computer simulation, the behaviour of a 20-cell InGaP/In0.01GaAs/Ge multi-junction concentrator system was simulated in 5-min intervals over an entire year, accounting for changes in direct normal irradiance, humidity, temperature and aerosol optical depth. The simulation was compared with concentrator system monitoring data taken over the same period and excellent agreement (within 2%) in the annual energy yield was obtained. Air mass, aerosol optical depth and precipitable water have been identified as atmospheric parameters with the largest impact on system efficiency.

  • Journal article
    Cotter CJ, Holm DD, 2012,

    On Noether's Theorem for the Euler-Poincaré equation on the diffeomorphism group with advected quantities

    , Foundations of Computational Mathematics, ISSN: 1615-3375
  • Journal article
    Woodward G, Gessner MO, Giller PS, Gulis V, Hladyz S, Lecerf A, Malmqvist B, McKie BG, Tiegs SD, Cariss H, Dobson M, Elosegi A, Ferreira V, Graça MAS, Fleituch T, Lacoursière JO, Nistorescu M, Pozo J, Risnoveanu G, Schindler M, Vadineanu A, Vought LB-M, Chauvet Eet al., 2012,

    Continental-scale effects of nutrient pollution on stream ecosystem functioning.

    , Science, Vol: 336, Pages: 1438-1440

    Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

  • Journal article
    Beven K, Buytaert W, Smith LA, 2012,

    On virtual observatories and modelled realities (or why discharge must be treated as a virtual variable)

    , HYDROLOGICAL PROCESSES, Vol: 26, Pages: 1906-1909, ISSN: 0885-6087
  • Journal article
    Sanchez ST, Woods J, Akhurst M, Brander M, O'Hare M, Dawson TP, Edwards R, Liska AJ, Malpas Ret al., 2012,

    Accounting for indirect land-use change in the life cycle assessment of biofuel supply chains

    , JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 9, Pages: 1105-1119, ISSN: 1742-5689
  • Journal article
    Gires A, Onof C, Maksimovic C, Schertzer D, Tchiguirinskaia I, Simoes Net al., 2012,

    Quantifying the impact of small scale unmeasured rainfall variability on urban runoff through multifractal downscaling: A case study

    , JOURNAL OF HYDROLOGY, Vol: 442, Pages: 117-128, ISSN: 0022-1694
  • Journal article
    O'Reilly CH, Czaja A, LaCasce JH, 2012,

    The emergence of zonal ocean jets under large-scale stochastic wind forcing

  • Journal article
    Keivanidis PE, Kamm V, Zhang W, Floudas G, Laquai F, McCulloch I, Bradley DDC, Nelson Jet al., 2012,

    Correlating Emissive Non-Geminate Charge Recombination with Photocurrent Generation Efficiency in Polymer/Perylene Diimide Organic Photovoltaic Blend Films

    , ADVANCED FUNCTIONAL MATERIALS, Vol: 22, Pages: 2318-2326, ISSN: 1616-301X
  • Journal article
    Chiong MS, Rajoo S, Romagnoli A, Martinez-Botas RFet al., 2012,

    Single entry mixed flow turbine performance prediction with 1-D gas dynamic code coupled with mean line model

    , International Journal of Gas Turbine, Propulsion and Power Systems, Vol: 4, Pages: 8-16

    It is a well known fact that turbocharger works with pulsating exhaust flow in its entire operating life, hence the need to predict unsteady performance. This paper presents the unsteady performance prediction resultof a single entry nozzleless mixed flow turbine under steady flow and 60 Hz pulsating flow at 43.0 rps/ √ K operating speed. The modeling method coupled one-dimensional gas dynamic modelwith a mean-line model to predict the turbine efficiency by appropriate losses consideration. The coupled method assumes that the turbine volute has a large volume and length, so that unsteadiness effect of the pulsating flow is significant while the rotor is assumed to behave quasisteadily. A pressure drop boundary is used to simulate pressure drop across the turbine volute. The coupled method was validated with the experimentally measured steady state results of the same turbine. Experimentally measured total conditions of the flow were used as inlet conditions for the model during unsteady analysis. The predicted isentropic power averaged results show convincing match with the experimental data. This will set forward a systematic approach for engine designers to evaluate turbine performance beyond what will be normally provided by turbocharger manufacturers, which is the steady state map. Copyright © 2012 Gas Turbine Society of Japan.

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: Request URI: /respub/WEB-INF/jsp/search-t4-html.jsp Query String: id=278&limit=30&page=48&respub-action=search.html Current Millis: 1708907814917 Current Time: Mon Feb 26 00:36:54 GMT 2024