370 research outputs found

    Supporting public decision making in policy deliberations: An ontological approach

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    This is the post-print version of the Paper. The official published version can be accessed from the link below - Copyright @ 2011 SpringerSupporting public decision making in policy deliberations has been a key objective of eParticipation which is an emerging area of eGovernment. EParticipation aims to enhance citizen involvement in public governance activities through the use of information and communication technologies. An innovative approach towards this objective is exploiting the potentials of semantic web technologies centred on conceptual knowledge models in the form of ontologies. Ontologies are generally defined as explicit human and computer shared views on the world of particular domains. In this paper, the potentials and benefits of using ontologies for policy deliberation processes are discussed. Previous work is then extended and synthesised to develop a deliberation ontology. The ontology aims to define the necessary semantics in order to structure and interrelate the stages and various activities of deliberation processes with legal information, participant stakeholders and their associated arguments. The practical implications of the proposed framework are illustrated.This work is funded by the European Commission under the 2006/1 eParticipation call

    Synthesis of perfluorinated polyethers

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    A series of highly fluorinated acetylenes was prepared and their cyclization reactions were studied. A series of perfluoropolytriazines with -CF2I pendent groups were prepared. These materials can be cured thermally or photochemically to an elastomeric gum. Perfluoropolytriazines with -CN pendent groups were prepared. These materials can be crosslinked by reaction with terephthalonitrile oxide

    HNBR and its MWCNT reinforced nanocomposites : Crystalline morphology and electrical response

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    Morphology and electrical response of hydrogenated acrylonitrile butadiene rubber (HNBR) and its multiwall carbon nanotube (MWCNT) reinforced nanocomposites were studied by means of x-ray diffraction and broadband dielectric spectroscopy. HNBR systems were found to be semi-crystalline, with their crystallinity to increase with the addition of MWCNTs. In their dielectric spectra, four relaxation processes were detected. Ascending in relaxation time, these were attributed to: (i) interfacial polarization at the interface of crystalline and amorphous regions of HNBR and at the interface between HNBR and MWCNTs, (ii) glass to rubber transition of the amorphous part of HNBR, (iii) rearrangement of polar side groups, such as –CN, and (iv) local motions of small segments of the main elastomer chain. Electrical conductivity increases with MWCNT content and frequency increasing. The effect of temperature, on the electrical response, is more pronounced at low frequencies. The temperature dependence of the electrical conductivity strongly deviates from a pure Arrhenius behavior, signifying that the occurring conductance mechanisms do not correspond to a single thermally activated process. Relaxation dynamics imply that crystalline regions exert motion restrictions to large segments of the macromolecules in the amorphous phase and to polar parts of the systems

    Novel Catalysts and Processing Technologies for Production of Aerospace Fuels from Non-Petroleum Raw Materials

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    Transportation fuels production (including aerospace propellants) from non-traditional sources (gases, waste materials, and biomass) has been an active area of research and development for decades. Reducing terrestrial waste streams simultaneous with energy conversion, plentiful biomass, new low-cost methane sources, and/or extra-terrestrial resource harvesting and utilization present significant technological and business opportunities being realized by a new generation of visionary entrepreneurs. We examine several new approaches to catalyst fabrication and new processing technologies to enable utilization of these nontraditional raw materials. Two basic processing architectures are considered: a single-stage pyrolysis approach that seeks to basically re-cycle hydrocarbons with minimal net chemistry or a two-step paradigm that involves production of supply or synthesis gas (mainly carbon oxides and H2) followed by production of fuel(s) via Sabatier or methanation reactions and/or Fischer-Trpsch synthesis. Optimizing the fraction of product stream relevant to targeted aerospace (and other transportation) fuels via modeling, catalyst fabrication and novel reactor design are described. Energy utilization is a concern for production of fuels for either terrestrial or space operations; renewable sources based on solar energy and/or energy efficient processes may be mission enabling. Another important issue is minimizing impurities in the product stream(s), especially those potentially posing risks to personnel or operations through (catalyst) poisoning or (equipment) damage. Technologies being developed to remove (and/or recycle) heteroatom impurities are briefly discussed as well as the development of chemically robust catalysts whose activities are not diminished during operation. The potential impacts on future missions by such new approaches as well as balance of system issues are addressed

    Gold/ultra-high molecular weight polyethylene nanocomposites for electrical energy storage: Enhanced recovery efficiency upon uniaxial deformation

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    13 pags., 9 figs.The growing demand for renewable energy sources has prompted the development of dielectric materials with the ability to store and efficiently recover electrical energy. Here, we correlate the structure and thermal conductivity of uniaxially oriented disentangled ultra-high molecular weight polyethylene (dis-UHMWPE) composites reinforced with gold nanoparticles with their electrical properties and potential application as electrical energy storage devices. Stretching increases the orientation of the polymer chains and thus the crystallinity and reduces the aggregation of gold nanoparticles while the thermal conductivity enhances significantly along the orientation axis. The structural changes driven by stretching result in two competing effects; on the one hand, the crystallinity increase reduces the permittivity of the composites and increases the resistivity, while on the other hand the recovery efficiency of oriented materials excels that of unstretched samples by up to 6 times at 5 s. Therefore, our work shows the structure–property relationship in electrical energy storage materials.Engineering and Physical Sciences Research Council, Grant/Award Number: EP/K034405/
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