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Journal articleKline KL, Msangi S, Dale VH, et al.,
Reconciling biofuels and food security: priorities for action
, Global Change Biology Bioenergy, ISSN: 1757-1693Addressing the challenges of understanding and managing complex interactions among food security, biofuels, and resource management requires a focus on specific contextual problems and opportunities. The United Nations’ 2030 Sustainable Development Goals prioritize food and energy security; bioenergy plays an important role in achieving both goals. Effective food security programs begin by clearly defining the problem and asking, “What can be done to effectively assist people at high risk?” Headlines and cartoons that blame biofuels for food insecurity may reflect good intentions but mislead the public and policy makers because they obscure the main drivers of local food insecurity and ignore opportunities for biofuels to contribute to solutions. Applying sustainability guidelines to bioenergy will help achieve near- and long- term goals to eradicate hunger. Priorities for achieving successful synergies between bioenergy and food security include (1) clarifying communications with clear and consistent terms, (2) recognizing that food and bioenergy need not compete for land and instead, need to be integrated with improved resource management, (3) investing in innovations to build capacity and infrastructure such as rural agricultural extension and technology, (4) promoting stable prices that incentivize local production, (5) adopting flex crops that can provide food along with other products and services to society, and (6) engaging stakeholders in identifying and assessing specific opportunities for biofuels to improve food security. Systematic monitoring and analysis to support adaptive management and continual improvement are essential elements to build synergies and help society equitably meet growing demands for both food and energy.
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Journal articleHuck CE, van de Flierdt T, Jimenez-Espejo FJ, et al., 2016,
Robustness of fossil fish teeth for seawater neodymium isotope reconstructions under variable redox conditions in an ancient shallow marine setting
, Geochemistry, Geophysics, Geosystems, Vol: 17, Pages: 679-698, ISSN: 1525-2027Fossil fish teeth from pelagic open ocean settings are considered a robust archive for preserving the neodymium (Nd) isotopic composition of ancient seawater. However, using fossil fish teeth as an archive to reconstruct seawater Nd isotopic compositions in different sedimentary redox environments and in terrigenous-dominated, shallow marine settings is less proven. To address these uncertainties, fish tooth and sediment samples from a middle Eocene section deposited proximal to the East Antarctic margin at Integrated Ocean Drilling Program Site U1356 were analyzed for major and trace element geochemistry, and Nd isotopes. Major and trace element analyses of the sediments reveal changing redox conditions throughout deposition in a shallow marine environment. However, variations in the Nd isotopic composition and rare earth element (REE) patterns of the associated fish teeth do not correspond to redox changes in the sediments. REE patterns in fish teeth at Site U1356 carry a typical mid-REE-enriched signature. However, a consistently positive Ce anomaly marks a deviation from a pure authigenic origin of REEs to the fish tooth. Neodymium isotopic compositions of cleaned and uncleaned fish teeth fall between modern seawater and local sediments and hence could be authigenic in nature, but could also be influenced by sedimentary fluxes. We conclude that the fossil fish tooth Nd isotope proxy is not sensitive to moderate changes in pore water oxygenation.However, combined studies on sediments, pore waters, fish teeth and seawater are needed to fully understand processes driving the reconstructed signature from shallow marine sections in proximity to continental sources.
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Journal articleGuarracino I, Mellor A, Ekins-Daukes N, et al., 2016,
Dynamic coupled thermal-and-electrical modelling of sheet-and-tube hybrid photovoltaic/thermal (PVT) collectors
, Applied Thermal Engineering, Vol: 101, Pages: 778-795, ISSN: 1873-5606In this paper we present a dynamic model of a hybrid photovoltaic/thermal (PVT) collector with a sheet-and-tube thermal absorber. The model is used in order to evaluate the annual generation of electrical energy along with the provision of domestic hot-water (DHW) from the thermal energy output, by using real climate-data at high temporal resolution. The model considers the effect of a non-uniform temperature distribution on the surface of the solar cell on its electrical power output. An unsteady 3-dimensional numerical model is developed to estimate the performance of such a collector. The model allows key design parameters of the PVT collector to vary so that the influence of each parameter on the system performance can be studied at steady state and at varying operating and atmospheric conditions. A key parameter considered in this paper is the number of glass covers used in the PVT collector. The results show that while the thermal efficiency increases with the additional glazing, the electrical efficiency deteriorates due to the higher temperature of the fluid and increased optical losses, as expected. This paper also shows that the use of a dynamic model and of real climate-data at high resolution is of fundamental importance when evaluating the yearly performance of the system. The results of the dynamic simulation with 1-min input data show that the thermal output of the system is highly dependent on the choice of the control parameters (pump operation, differential thermostat controller, choice of flow rate etc.) in response to the varying weather conditions. The effect of the control parameters on the system's annual performance can be captured and understood only if a dynamic modelling approach is used. The paper also discusses the use of solar cells with modified optical properties (reduced absorptivity/emissivity) in the infrared spectrum, which would reduce the thermal losses of the PVT collector at the cost of only a small loss in electrical output
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Journal articleDe Marco MDM, Markoulidis F, Menzel R, et al., 2016,
Cross-linked single-walled carbon nanotube aerogel electrodes via reductive coupling chemistry
, Journal of Materials Chemistry A, Vol: 4, Pages: 5385-5389, ISSN: 2050-7496Single-walled carbon nanotube (SWCNT) anions can be cross-linked by a dielectrophile to form covalent, carbon-bonded organogels. Freeze-drying produces cryogels with low density (2.3 mg cm−3), high surface area (766 m2 g−1), and high conductivity (9.4 S m−1), showing promise as supercapacitor electrodes. Counterion concentration controls debundling, grafting ratio, as well as all the resulting properties.
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Journal articleO'Gorman EJ, Ólafsson Ó, Demars BOL, et al., 2016,
Temperature effects on fish production across a natural thermal gradient
, Global Change Biology, Vol: 22, Pages: 3206-3220, ISSN: 1365-2486Global warming is widely predicted to reduce the biomass production of top predators, or even result in species loss. Several exceptions to this expectation have been identified, however, and it is vital that we understand the underlying mechanisms if we are to improve our ability to predict future trends. Here, we used a natural warming experiment in Iceland and quantitative theoretical predictions to investigate the success of brown trout as top predators across a stream temperature gradient (4–25 °C). Brown trout are at the northern limit of their geographic distribution in this system, with ambient stream temperatures below their optimum for maximal growth, and above it in the warmest streams. A five-month mark-recapture study revealed that population abundance, biomass, growth rate, and production of trout all increased with stream temperature. We identified two mechanisms that contributed to these responses: (1) trout became more selective in their diet as stream temperature increased, feeding higher in the food web and increasing in trophic position; and (2) trophic transfer through the food web was more efficient in the warmer streams. We found little evidence to support a third potential mechanism: that external subsidies would play a more important role in the diet of trout with increasing stream temperature. Resource availability was also amplified through the trophic levels with warming, as predicted by metabolic theory in nutrient-replete systems. These results highlight circumstances in which top predators can thrive in warmer environments and contribute to our knowledge of warming impacts on natural communities and ecosystem functioning.
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Journal articleAl-Menhali AS, Krevor S, 2016,
Capillary trapping of CO2 in oil reservoirs: observations in a mixed-wet carbonate rock
, Environmental Science & Technology, Vol: 50, Pages: 2727-2734, ISSN: 1520-5851Early deployment of carbon dioxide storage is likely to focus on injection into mature oil reservoirs, most of which occur in carbonate rock units. Observations and modeling have shown how capillary trapping leads to the immobilization of CO2 in saline aquifers, enhancing the security and capacity of storage. There are, however, no observations of trapping in rocks with a mixed-wet-state characteristic of hydrocarbon-bearing carbonate reservoirs. Here, we found that residual trapping of supercritical CO2 in a limestone altered to a mixed-wet state with oil was significantly less than trapping in the unaltered rock. In unaltered samples, the trapping of CO2 and N2 were indistinguishable, with a maximum residual saturation of 24%. After the alteration of the wetting state, the trapping of N2 was reduced, with a maximum residual saturation of 19%. The trapping of CO2 was reduced even further, with a maximum residual saturation of 15%. Best-fit Land-model constants shifted from C = 1.73 in the water-wet rock to C = 2.82 for N2 and C = 4.11 for the CO2 in the mixed-wet rock. The results indicate that plume migration will be less constrained by capillary trapping for CO2 storage projects using oil fields compared with those for saline aquifers.
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Journal articleSchlaphorst D, Kendall JM, Collier JS, et al., 2016,
Water, oceanic fracture zones and the lubrication of subducting plate boundaries - insights from seismicity
, Geophysical Journal International, Vol: 204, Pages: 1405-1420, ISSN: 0956-540XWe investigate the relationship between subduction processes and related seismicity for the Lesser Antilles Arc using the Gutenberg-Richter law. This power lawdescribes the earthquakemagnitude distribution, with the gradient of the cumulative magnitude distribution being commonly known as the b-value. The Lesser Antilles Arc was chosen because of its alongstrike variability in sediment subduction and the transition from subduction to strike-slip movement towards its northern and southern ends. The data are derived from the seismicity catalogues from the Seismic Research Centre of The University of the West Indies and the Observatoires Volcanologiques et Sismologiques of the Institut de Physique du Globe de Paris and consist of subcrustal events primarily from the slab interface. The b-value is found using a Kolmogorov-Smirnov test for a maximum-likelihood straight line-fitting routine. We investigate spatial variations in b-values using a grid-search with circular cells as well as an along-arc projection. Tests with different algorithms and the two independent earthquake cataloges provide confidence in the robustness of our results. We observe a strong spatial variability of the b-value that cannot be explained by the uncertainties. Rather than obtaining a simple north-south b-value distribution suggestive of the dominant control on earthquake triggering being water released from the sedimentary cover on the incoming American Plates, or a b-value distribution that correlates with on the obliquity of subduction, we obtain a series of discrete, high b-value 'bull's-eyes' along strike. These bull's-eyes, which indicate stress release through a higher fraction of small earthquakes, coincide with the locations of known incoming oceanic fracture zones on the American Plates. We interpret the results in terms of water being delivered to the Lesser Antilles subduction zone in the vicinity of fracture zones providing lubrication and thus changing the character of the related
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Journal articleFecht D, Hansell A, Morley D, et al., 2016,
Spatial and temporal associations of road traffic noise and air pollution in London: Implications for epidemiological studies
, Environment International, Vol: 88, Pages: 235-242, ISSN: 0160-4120Road traffic gives rise to noise and air pollution exposures, both of which are associated with adverse health effects especially for cardiovascular disease, but mechanisms may differ. Understanding the variability in correlations between these pollutants is essential to understand better their separate and joint effects on human health.We explored associations between modelled noise and air pollutants using different spatial units and area characteristics in London in 2003–2010.We modelled annual average exposures to road traffic noise (LAeq,24 h, Lden, LAeq,16 h, Lnight) for ~ 190,000 postcode centroids in London using the UK Calculation of Road Traffic Noise (CRTN) method. We used a dispersion model (KCLurban) to model nitrogen dioxide, nitrogen oxide, ozone, total and the traffic-only component of particulate matter ≤ 2.5 μm and ≤ 10 μm. We analysed noise and air pollution correlations at the postcode level (~ 50 people), postcodes stratified by London Boroughs (~ 240,000 people), neighbourhoods (Lower layer Super Output Areas) (~ 1600 people), 1 km grid squares, air pollution tertiles, 50 m, 100 m and 200 m in distance from major roads and by deprivation tertiles.Across all London postcodes, we observed overall moderate correlations between modelled noise and air pollution that were stable over time (Spearman's rho range: | 0.34–0.55 |). Correlations, however, varied considerably depending on the spatial unit: largest ranges were seen in neighbourhoods and 1 km grid squares (both Spearman's rho range: | 0.01–0.87 |) and was less for Boroughs (Spearman's rho range: | 0.21–0.78 |). There was little difference in correlations between exposure tertiles, distance from road or deprivation tertiles.Associations between noise and air pollution at the relevant geographical unit of analysis need to be carefully considered in any epidemiological analysis, in particular in complex urban areas. Low correlations near roads, however, sugges
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Journal articleGiarola S, Romain C, Williams C, et al., 2016,
Techno-economic assessment of the production of phthalic anhydride from corn stover
, Chemical Engineering Research & Design, Vol: 107, Pages: 181-194, ISSN: 1744-3563Phthalic anhydride is used worldwide for an extremely broad range of applications spanning from the plastics industry to the synthesis of resins, agricultural fungicides and amines. This work proposes a conceptual design of a process for the production of phthalic anhydride from an agricultural residue (i.e. corn stover), energy integration alternatives as well as water consumption and life cycle greenhouse emissions assessment. The techno-economic and financial appraisal of the flowsheet proposed is performed. Results show how the valorization of all the carbohydrate-rich fractions present in the biomass as well as energy savings and integration is crucial to obtain an economically viable process and that it is in principle possible to produce renewable phthalic anhydride in a cost-competitive fashion with a lower impact on climate change compared to the traditional synthetic route.
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Journal articleRojas-Rueda D, de Nazelle A, Andersen ZJ, et al., 2016,
Health impacts of active transportation in Europe
, PLOS One, Vol: 11, ISSN: 1932-6203Policies that stimulate active transportation (walking and bicycling) have been related to heath benefits. This study aims to assess the potential health risks and benefits of promoting active transportation for commuting populations (age groups 16–64) in six European cities. We conducted a health impact assessment using two scenarios: increased cycling and increased walking. The primary outcome measure was all-cause mortality related to changes in physical activity level, exposure to fine particulate matter air pollution with a diameter <2.5 μm, as well as traffic fatalities in the cities of Barcelona, Basel, Copenhagen, Paris, Prague, and Warsaw. All scenarios produced health benefits in the six cities. An increase in bicycle trips to 35% of all trips (as in Copenhagen) produced the highest benefits among the different scenarios analysed in Warsaw 113 (76–163) annual deaths avoided, Prague 61 (29–104), Barcelona 37 (24–56), Paris 37 (18–64) and Basel 5 (3–9). An increase in walking trips to 50% of all trips (as in Paris) resulted in 19 (3–42) deaths avoided annually in Warsaw, 11(3–21) in Prague, 6 (4–9) in Basel, 3 (2–6) in Copenhagen and 3 (2–4) in Barcelona. The scenarios would also reduce carbon dioxide emissions in the six cities by 1,139 to 26,423 (metric tonnes per year). Policies to promote active transportation may produce health benefits, but these depend of the existing characteristics of the cities. Increased collaboration between health practitioners, transport specialists and urban planners will help to introduce the health perspective in transport policies and promote active transportation.
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Journal articleQuattrocchi G, Gorman GJ, Piggott MD, et al., 2016,
M2, overtides and compound tides generation in the Strait of Messina: the response of a non-hydrostatic, finite-element ocean model
, JOURNAL OF COASTAL RESEARCH, Pages: 657-661, ISSN: 0749-0208- Author Web Link
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Journal articleBall WT, Haigh JD, Rozanov EV, et al., 2016,
High solar cycle spectral variations inconsistent with stratospheric ozone observations
, Nature Geoscience, Vol: 9, Pages: 206-209, ISSN: 1752-0894 -
Journal articleHuddart JEA, Thompson MSA, Woodward G, et al., 2016,
Citizen science: from detecting pollution to evaluating ecological restoration
, Wiley Interdisciplinary Reviews: Water, Vol: 3, Pages: 287-300, ISSN: 2049-1948 -
Journal articleSmith R, Hill J, Collins GS, et al., 2016,
Comparing approaches for numerical modelling of tsunami generation by deformable submarine slides
, Ocean Modelling, Vol: 100, Pages: 125-140, ISSN: 1463-5003Tsunami generated by submarine slides are arguably an under-consideredrisk in comparison to earthquake-generated tsunami. Numerical simulationsof submarine slide-generated waves can be used to identify the important factorsin determining wave characteristics. Here we use Fluidity, an open sourcefinite element code, to simulate waves generated by deformable submarineslides. Fluidity uses flexible unstructured meshes combined with adaptivitywhich alters the mesh topology and resolution based on the simulationstate, focussing or reducing resolution, when and where it is required. Fluidityalso allows a number of different numerical approaches to be taken tosimulate submarine slide deformation, free-surface representation, and wavegeneration within the same numerical framework. In this work we use amulti-material approach, considering either two materials (slide and waterwith a free surface) or three materials (slide, water and air), as well as asediment model (sediment, water and free surface) approach. In all casesthe slide is treated as a viscous fluid. Our results are shown to be consistentwith laboratory experiments using a deformable submarine slide, anddemonstrate good agreement when compared with other numerical models.The three different approaches for simulating submarine slide dynamics andtsunami wave generation produce similar waveforms and slide deformationgeometries. However, each has its own merits depending on the application.Mesh adaptivity is shown to be able to reduce the computational cost withoutcompromising the accuracy of results.
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Journal articleAlmeida S, Le Vine N, McIntyre N, et al., 2016,
Accounting for dependencies in regionalized signatures for predictions in ungauged catchments
, Hydrology and Earth System Sciences, Vol: 20, Pages: 887-901, ISSN: 1607-7938A recurrent problem in hydrology is the absence of streamflow data to calibrate rainfall-runoff models. A commonly used approach in such circumstances conditions model parameters on regionalized response signatures. While several different signatures are often available to be included in this process, an outstanding challenge is the selection of signatures that provide useful and complementary information. Different signatures do not necessarily provide independent information and this has led to signatures being omitted or included on a subjective basis. This paper presents a method that accounts for the inter-signature error correlation structure so that regional information is neither neglected nor double-counted when multiple signatures are included. Using 84 catchments from the MOPEX database, observed signatures are regressed against physical and climatic catchment attributes. The derived relationships are then utilized to assess the joint probability distribution of the signature regionalization errors that is subsequently used in a Bayesian procedure to condition a rainfall-runoff model. The results show that the consideration of the inter-signature error structure may improve predictions when the error correlations are strong. However, other uncertainties such as model structure and observational error may outweigh the importance of these correlations. Further, these other uncertainties cause some signatures to appear repeatedly to be misinformative.
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Journal articleHoque MA, Scheelbeek PFD, Vineis P, et al., 2016,
Drinking water vulnerability to climate change and alternatives for adaptation in coastal South and South East Asia
, Climatic Change, Vol: 136, Pages: 247-236, ISSN: 0165-0009Drinking water in much of Asia, particularly in coastal and rural settings, isprovided by a variety of sources, which are widely distributed and frequently managed atan individual or local community level. Coastal and near-inland drinking water sources inSouth and South East (SSE) Asia are vulnerable to contamination by seawater, mostdramatically from tropical cyclone induced storm surges. This paper assesses spatialvulnerabilities to salinisation of drinking water sources due to meteorological variabilityand climate change along the (ca. 6000 km) coastline of SSE Asia. The risks of increasingclimatic stresses are first considered, and then maps of relative vulnerability along theentire coastline are developed, using data from global scale land surface models, alongwith an overall vulnerability index. The results show that surface and near-surfacedrinking water in the coastal areas of the mega-deltas in Vietnam and Bangladesh-Indiaare most vulnerable, putting more than 25 million people at risk of drinking ‘saline’ water.Climate change is likely to exacerbate this problem, with adverse consequences for health,such as prevalence of hypertension and cardiovascular diseases. There is a need foridentifying locations that are most at risk of salinisation in order for policy makers andlocal officials to implement strategies for reducing these health impacts. To counter therisks associated with these vulnerabilities, possible adaptation measures are also outlined.
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Journal articleStanley E, Plant J, Voulvoulis N, 2016,
Environmental chemical exposures and breast cancer
, AIMS Environmental Science, Vol: 3, Pages: 96-114, ISSN: 2372-0352As a hormone-sensitive condition with no single identifiable cause, breast cancer is a major health problem. It is characterized by a wide range of contributing factors and exposures occurring in different combinations and strengths across a lifetime that may be amplified during periods of enhanced developmental susceptibility and impacted by reproductive patterns and behaviours. The vast majority of cases are oestrogen-receptor positive and occur in women with no family history of the disease suggesting that modifiable risk factors are involved. A substantial body of evidence now links oestrogen-positive breast cancer with environmental exposures. Synthetic chemicals capable of oestrogen mimicry are characteristic of industrial development and have been individually and extensively assessed as risk factors for oestrogen-sensitive cancers. Existing breast cancer risk assessment tools do not take such factors into account. In the absence of consensus on causation and in order to better understand the problem of escalating incidence globally, an expanded, integrated approach broadening the inquiry into individual susceptibility breast cancer is proposed. Applying systems thinking to existing data on oestrogen-modulating environmental exposures and other oestrogenic factors characteristic of Westernisation and their interactions in the exposure, encompassing social, behavioural, environmental, hormonal and genetic factors, can assist in understanding cancer risks and the pursuit of prevention strategies. A new conceptual framework based on a broader understanding of the “system” that underlies the development of breast cancer over a period of many years, incorporating the factors known to contribute to breast cancer risk, could provide a new platform from which government and regulators can promulgate enhanced and more effective prevention strategies.
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Journal articleMac Dowell N, Staffell I, 2016,
The role of flexible CCS in the UK's future energy system
, International Journal of Greenhouse Gas Control, Vol: 48, Pages: 327-344, ISSN: 1750-5836That CCS will be required to operate in a flexible and load following fashion in the diverse energy landscape of the 21st century is well recognised. However, what is less well understood is how these plants will be dispatched at the unit generator scale, and what effect this will have on the performance and behaviour of the plant at the individual unit operation level. To address this gap, we couple an investment and unit commitment energy system model with a detailed plant-level model of a super-critical coal-fired power station integrated with an amine-based post-combustion CO2 capture process. We provide insight into the likely role of coal and gas CCS plants in the UK's energy system in the 2030s, 2040s and 2050s. We then evaluate the impact that this has on the performance of an individual coal CCS plant operating in this system, and chart its evolution throughout this period. Owing to the increased frequency and duration of part-load operation, asset utilisation and average efficiency suffer, leading to a substantially increased LCOE, implying that CCS costs will need to decrease more rapidly than is currently expected. Further, as a direct consequence of the dynamic operation, the interaction of the CCS plants with the downstream CO2 transport network is characterised by highly transient behaviour, including periods during which no CO2 is injected to the transport network, implying that the transport system must therefore be designed to incorporate this variability of supply.
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Journal articleBarraclough TG, Bell TDC, Rivett D, et al., 2016,
Resource-dependent attenuation of species interactions during bacterial succession
, ISME Journal, Vol: 10, Pages: 2259-2268, ISSN: 1751-7362Bacterial communities are vital for many economically and ecologically important processes. The role of bacterial community composition in determining ecosystem functioning depends critically on interactions among bacterial taxa. Several studies have shown that, despite a predominance of negative interactions in communities, bacteria are able to display positive interactions given the appropriate evolutionary or ecological conditions. We were interested in how interspecific interactions develop over time in a naturalistic setting of low resource supply rates. We assembled aquatic bacterial communities in microcosms and assayed the productivity (respiration and growth) and substrate degradation while tracking community composition. The results demonstrated that while bacterial communities displayed strongly negative interactions during the early phase of colonisation and acclimatisation to novel biotic and abiotic factors, this antagonism declined over time towards a more neutral state. This was associated with a shift from use of labile substrates in early succession to use of recalcitrant substrates later in succession, confirming a crucial role of resource dynamics in linking interspecific interactions with ecosystem functioning.
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Journal articleEmmott CJM, Moia D, Sandwell P, et al., 2016,
In-situ, long-term operational stability of organic photovoltaics for off-grid applications in Africa
, Solar Energy Materials and Solar Cells, Vol: 149, Pages: 284-293, ISSN: 0927-0248 -
Journal articleHerceg TM, Yoon S-H, Abidin MSZ, et al., 2016,
Thermosetting nanocomposites with high carbon nanotube loadings processed by a scalable powder based method
, Composites Science and Technology, Vol: 127, Pages: 62-70, ISSN: 0266-3538A powder based processing route was developed to allow manufacturing of thermosettingnanocomposites with high (20 wt%) carbon nanotube (CNT) loading fractions. Adaptation ofhigh shear mixing methods, as used in thermoplastic processing, ensured that the CNTs werewell distributed and dispersed even at the highest loadings. By minimising flow distances,compression moulding of powders ensured that the CNTs did not agglomerate duringconsolidation, and yielded a percolated CNT network in a nanocomposite with excellentelectrical and thermal conductivities of 67 S m-1and 0.77 W m-1 K-1, respectively. Unusually,the CNTs provided effective mechanical reinforcement at even the highest loadings;embrittlement is minimised by avoiding large scale inhomogeneities and the maximummeasured Young’s modulus (5.4 GPa) and yield strength (90 MPa) could make thenanocomposite an attractive matrix for continuous fibre composites. The macromechanicalmeasurements were interpolated using micromechanical models that were previouslysuccessfully applied at the nanoscale.
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Journal articleCotter CJ, Kuzmin D, 2016,
Embedded discontinuous Galerkin transport schemes with localised limiters
, Journal of Computational Physics, Vol: 311, Pages: 363-373, ISSN: 0021-9991Motivated by finite element spaces used for representation of temperature in the compatible fi-nite element approach for numerical weather prediction, we introduce locally bounded transportschemes for (partially-)continuous finite element spaces. The underlying high-order transportscheme is constructed by injecting the partially-continuous field into an embedding discontinuousfinite element space, applying a stable upwind discontinuous Galerkin (DG) scheme, and projectingback into the partially-continuous space; we call this an embedded DG transport scheme. Weprove that this scheme is stable in L2 provided that the underlying upwind DG scheme is. Wethen provide a framework for applying limiters for embedded DG transport schemes. StandardDG limiters are applied during the underlying DG scheme. We introduce a new localised form ofelement-based flux-correction which we apply to limiting the projection back into the partiallycontinuousspace, so that the whole transport scheme is bounded. We provide details in the specificcase of tensor-product finite element spaces on wedge elements that are discontinuous P1/Q1 inthe horizontal and continuous P2 in the vertical. The framework is illustrated with numericaltests.
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Journal articleManz B, Buytaert W, Zulkafli Z, et al., 2016,
High-resolution Satellite-Gauge Merged Precipitation Climatologies of the Tropical Andes
, Journal of Geophysical Research: Atmospheres, Vol: 121, Pages: 1190-1207, ISSN: 2169-897XSatellite precipitation products are becoming increasingly useful to complement rain gauge networks in regions where these are too sparse to capture spatial precipitation patterns, such as in the tropical Andes. The Tropical Rainfall Measuring Mission Precipitation Radar (TPR) was active for 17 years (1998 - 2014) and has generated one of the longest single-sensor, high-resolution and high-accuracy rainfall records. In this study, high-resolution (5 km) gridded mean monthly climatological precipitation is derived from the raw orbital TPR data (TRMM 2A25) and merged with 723 rain gauges using multiple satellite-gauge (S-G) merging approaches. The resulting precipitation products are evaluated by cross-validation and catchment water balances (runoff ratios) for 50 catchments across the tropical Andes. Results show that the TPR captures major synoptic and seasonal precipitation patterns and also accurately defines orographic gradients, but underestimates absolute monthly rainfall rates. The S-G merged products presented in this study constitute an improved source of climatological rainfall data, outperforming the gridded TPR product as well as a rain gauge-only product based on ordinary kriging. Among the S-G merging methods, performance of inverse-distance interpolation of satellite-gauge residuals was similar to that of geostatistical methods, which were more sensitive to gauge network density. High uncertainty and low performance of the merged precipitation products predominantly affected regions with low and intermittent precipitation regimes (e.g. Peruvian Pacific coast) and is likely linked to the low TPR sampling frequency. All S-G merged products presented in this study are available in the public domain.
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Journal articleLozano FJ, Freire P, Guillen-Gozalbez G, et al., 2016,
New perspectives for sustainable resource and energy use, management and transformation: approaches from green and sustainable chemistry and engineering
, Journal of Cleaner Production, Vol: 118, Pages: 1-3, ISSN: 0959-6526 -
Journal articleChayen N, shaffer, govada, et al., 2016,
Exploring Carbon Nanomaterial Diversity for Nucleation of Protein Crystals
, Scientific Reports, Vol: 6, ISSN: 2045-2322Controlling crystal nucleation is a crucial step in obtaining high quality protein crystals for structure determination by X-ray crystallography. Carbon nanomaterials (CNMs) including carbon nanotubes, graphene oxide, and carbon black provide a range of surface topographies, porosities and length scales; functionalisation with two different approaches, gas phase radical grafting and liquid phase reductive grafting, provide routes to a range of oligomer functionalised products. These grafted materials, combined with a range of controls, were used in a large-scale assessment of the effectiveness for protein crystal nucleation of 20 different carbon nanomaterials on five proteins. This study has allowed a direct comparison of the key characteristics of carbon-based nucleants: appropriate surface chemistry, porosity and/or roughness are required. The most effective solid system tested in this study, carbon black nanoparticles functionalised with poly(ethylene glycol) methyl ether of mean molecular weight 5000, provides a novel highly effective nucleant, that was able to induce crystal nucleation of four out of the five proteins tested at metastable conditions.
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Journal articleKoppelaar RHEM, Keirstead J, Shah N, et al., 2016,
A review of policy analysis purpose and capabilities of electricity system models
, Renewable & Sustainable Energy Reviews, Vol: 59, Pages: 1531-1544, ISSN: 1364-0321 -
Journal articleWoodward RT, Fam DWH, Anthony DB, et al., 2016,
Hierarchically porous carbon foams from pickering high internal phase emulsions
, Carbon, Vol: 101, Pages: 253-260, ISSN: 0008-6223Carbon foams were produced from a macroporous poly(divinylbenzene) (poly(DVB) precursor, synthesized by polymerizing the continuous but minority phase of water-in-oil high internal phase emulsions (HIPEs) stabilized by molecular and/or particulate emulsifiers. Both permeable and non-permeable hierarchically porous carbon foams, or ‘carboHIPEs’, were prepared by carbonization of the resulting macroporous polymers at 800 °C. The carbon yields were as high as 26 wt.% of the original polymer. CarboHIPEs retain the pore structure of the macroporous polymer precursor, but with surface areas of up to 505 m2/g and excellent electrical conductivities of 81 S/m. Contrary to some previous reports, the method does not require further modification, such as sulfonation or additional crosslinking of the polyHIPE prior to carbonization, due to the inherently crosslinked structure of poly(DVB). The use of a pourable, aqueous emulsion-template enables simple moulding, minimises waste and avoids the strong acid treatments used to remove many conventional solid-templates. The retention of the macroporous structure is coupled with the introduction of micropores during carbonization, producing hierarchically porous carboHIPEs, suitable for a wide range of applications as sorbents and electrodes.
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Journal articleLoveridge R, Wearn OR, Vieira M, et al., 2016,
Movement behaviour of native and invasive small mammals shows logging may facilitate invasion in a tropical rainforest
, Biotropica, Vol: 48, Pages: 373-380, ISSN: 1744-7429Invasive species pose one of the greatest threats to biodiversity. This study investigates the extent to which human disturbance to natural ecosystems facilitates the spread of non-native species, focusing on a small mammal community in selectively logged rainforest, Sabah, Borneo. The microhabitat preferences of the invasive Rattus rattus and three native species of small mammal were examined in three-dimensional space by combining the spool-and-line technique with a novel method for quantifying fine-scale habitat selection. These methods allowed the detection of significant differences for each species between the microhabitats used compared with alternative, available microhabitats that were avoided. Rattus rattus showed the greatest preference for heavily disturbed habitats and, in contrast to two native small mammals of the genus Maxomys, R. rattus showed high levels of arboreal behaviour, frequently leaving the forest floor and travelling through the under and mid-storey forest strata. This behaviour may enable R. rattus to effectively utilize the complex three-dimensional space of the lower strata in degraded forests, which is characterized by dense vegetation. The behavioural flexibility of R. rattus to operate in both terrestrial and arboreal space may facilitate its invasion into degraded forests. Human activities that generate heavily disturbed habitats preferred by R. rattus may promote the establishment of this invasive species in tropical forests in Borneo, and possibly elsewhere. We present this as an example of a synergistic effect, whereby forest disturbance directly threatens biodiversity, and indirectly increases the threat posed by invasive species, creating habitat conditions that facilitate the establishment of non-native fauna.
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Journal articleLanzini A, Guerra C, Leone P, et al., 2016,
Influence of the microstructure on the catalytic properties of SOFC anodes under dry reforming of methane
, MATERIALS LETTERS, Vol: 164, Pages: 312-315, ISSN: 0167-577X- Author Web Link
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Journal articleBlamey J, Fennell P, Anthony E, et al., 2016,
A shrinking core model for steam hydration of CaO-based sorbents cycled for CO2 capture
, Chemical Engineering Journal, Vol: 291, Pages: 298-305, ISSN: 1873-3212Calcium looping is a developing CO2 capture technology. It is based on the reversiblecarbonation of CaO sorbent, which becomes less reactive upon cycling. One method ofincreasing the reactivity of unreactive sorbent is by hydration in the calcined (CaO) form.Here, sorbent has been subjected to repeated cycles of carbonation and calcination within asmall fluidised bed reactor. Cycle numbers of 0 (i.e., one calcination), 2, 6 and 13 have beenstudied to generate sorbents that have been deactivated to different extents. Subsequently,the sorbent generated was subjected to steam hydration tests within a thermogravimetricanalyser, using hydration temperatures of 473, 573 and 673 K. Sorbents that had beencycled less prior to hydration hydrated rapidly. However, the more cycled sorbents exhibitedbehaviour where the hydration conversion tended towards an asymptotic value, which is likelyto be associated with pore blockage. This asymptotic value tended to be lower at higherhydration temperatures; however, the maximum rate of hydration was found to increase withincreasing hydration temperature. A shrinking core model has been developed and applied to 2the data. It fits data from experiments that did not exhibit extensive pore blockage well, butfits data from experiments that exhibited pore blockage less well
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