328 research outputs found

    Integrated Resource Planning for a Chinese Urban Development

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    Urban areas manage vast quantities of energy, water and waste resources. In order to minimise the cost and environmental impact, optimisation modelling is often used in the design and operation of these systems. However, traditional modelling approaches only consider the energy, water and waste sectors in isolation. This approach neglects the synergies possible between these systems whereby outputs from one system form an input to another, and hence sets an upper bound on economic and environmental impact minimisation. We formulate a mixed integer linear programming (MILP) model which takes a ‘systems-of-infrastructure systems’ approach to show how resource consumption can be reduced. The model takes as inputs possible resource conversion and transportation infrastructure and resources, and resource demands, and returns the optimal infrastructure choice and layout. The model is called PRaQ because it models ‘processes, resources and qualities.’ We apply the model to the design of a new urban development in China for three scenarios of various levels of resource integration. Results are still to be obtained

    Re-use of an ontology for modelling urban energy systems

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    The use of ontologies for the interoperability of software models is widespread, with many applications also in the energy domain. By formulating a shared data structure and a definition of concepts and their properties, a language is created that can be used between modellers and - formalised in an ontology - between model components. When modelling energy systems, connections between different infrastructures are critical, e.g. the interaction between the gas and electricity markets or the need for various infrastructures including power, heat, water and transport in cities. While a commonly shared ontology of energy systems would be highly desirable, the fact is that different existing models or applications already use dedicated ontologies, and have been demonstrated to work well using them. To benefit from linking data sources and connecting models developed with different ontologies, a translation between concepts can be made. In this paper a model of an urban energy system built upon one ontology is initialised using energy transformation technologies defined in another ontology, thus illustrating how this common perspective might benefit researchers in the energy domain. ©2010 IEEE

    Assessment of Design Procedures for Vertical Borehole Heat Exchangers

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    The use of ground source energy systems is a well-established method to provide low cost heating to buildings, diversify the energy mix and help meeting increasingly stricter sustainability targets. However, considerable uncertainties remain over their efficient design, with several standards, guidelines and manuals being proposed over the last few years. This paper aims at providing insight into the implications to the design of a vertical borehole heat exchanger of the adoption of different design procedures. The hypothetical case of a typical dwelling located in London, UK, is analysed in order to highlight the impact on the final design of the chosen methodology. Moreover, a parametric study using an analytical design procedure was performed to point out the influence of various factors, such as borehole characteristics and thermal properties of the ground. It is shown that there are considerable discrepancies between design methods and that uncertainties in some input parameters, such as the thermal properties of the ground, which for relatively small systems are often selected from tables rather than measured in situ, may have a substantial influence on the length of borehole required

    Introducing sustainable development with a mathematical model

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    Comparing performance metrics for multi-resource systems: the case of urban metabolism

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    We investigate different approaches to assessing the performance of multi-resource systems, i.e. networks of processes used to convert resource inputs to useful goods and services. For a given set of system outputs, alternative resource inputs are often possible so performance measures are needed to determine the best system configuration for a given goal. We define such performance measures according to a novel framework which categorises them into two types: those that can be calculated from a system's aggregate inputs and outputs (‘black-box’ metrics, e.g. carbon footprint); and those that require knowledge of resource conversion processes within the system (‘grey-box’ metrics). Urban areas are an important example application and metrics can be calculated from urban metabolism data. We calculate eight black-box metrics for fifteen global cities and find that performance is poorly correlated between the measures. This suggests that performance assessments should adopt grey-box approaches and consider flows at the level of individual processes within a city, using methods such as exergy analysis and ecological network analysis. We are led to suggest how to: (1) improve urban metabolism accounting to assist grey-box metric calculation, by including greater detail on conversion process and resource quality; and (2) promote these metrics amongst relevant decision makers

    Preliminary observations on soluble programmed cell death protein-1 as a prognostic and predictive biomarker in patients with metastatic melanoma treated with patient-specific autologous vaccines.

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    Because of its role as an immune checkpoint, levels of soluble programmed cell death protein-1 (sPD-1) could be useful as a prognostic biomarker or predictive biomarker in cancer patients treated with vaccines. Very low levels of sPD-1 may indicate lack of an existing anti-cancer immune response; very high levels may indicate an active immune response that is suppressed. In between these extremes, a decrease in PD-1 following injections of an anti-cancer vaccine may indicate an enhanced immune response that has not been suppressed. Blood samples obtained during a randomized trial in patients with metastatic melanoma were tested from 22 patients treated with a tumor cell vaccine (TCV) and 17 treated with a dendritic cell vaccine (DCV). Survival was better in DCV-treated patients. sPD-1 was measured at week-0, one week before the first of three weekly subcutaneous injections, and at week-4, one week after the third injection. The combination of a very low baseline sPD-1, or absence of a very high PD-1 at baseline followed by a decline in sPD-1 at week-4, was predictive of surviving three or more years in DCV-treated patients, but not TCV-treated. Among DCV-treated patients, these sPD-1 criteria appropriately classified 8/10 (80%) of 3-year survivors, and 6/7 (86%) of patients who did not survive three years. These preliminary observations suggest that sPD-1 might be a useful biomarker for melanoma patients being considered for treatment with this DCV vaccine, and/or to predict efficacy after only three injections, but this would have to be confirmed in larger studies
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