1,175 research outputs found

    An explorative philosophical study of envisaging the electrical energy infrastructure of the future

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    The electrical energy infrastructure is one of the key life-sustaining technologies of contemporary Western society. This infrastructure is extremely complex due to its size, its multifarious technologies, and its interweaving with societal structures. Smart grids are important in future infrastructure, yet extant literature does not adequately address this complexity. This paper argues that different elements of the philosophy of Dooyeweerd offer a key to understanding this intricate complexity more fundamentally. Key concepts are the ideas of normative practices, enkapsis (intertwinement) of practices, individuality structures, and ideals and basic beliefs. By developing these ideas in the context of smart grid engineering, our research contributes to philosophy of technology, philosophy of design, and philosophy of sustainability. It offers an ontological analysis of these infrastructures, pointing a direction to the development of workable infrastructures and supporting the transition to a sustainable society

    Dynamic impacts of a financial reform of the CAP on regional land use, income and overall growth

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    In this paper we investigate the impacts of abolishing the Common Agricultural Policy (CAP) for the post-2013 European Union (EU) financial perspective and the impacts of re-investing the released funds on research and development (R&D). We apply a linked system of models to analyze the impacts for the EU member states. The linked system consists of five land-use sector models (agriculture, forestry, urban area, tourism and transport infrastructure), which are connected to a macro-econometric model. Additionally, a land cover model is used to disaggregate land use countries to a 1 km² grid. Three scenarios are analysed. In the “baseline” currently decided policies are assumed to be continued until 2025. In the “tax rebate” scenario agricultural support (first pillar) is removed, and the member states’ contributions to EU lowered. In the “R&D investments” scenario agricultural support is also removed, and the released funds are used to increase general R&D efforts in the EU. We find that in both liberalization scenarios, agricultural producer prices drop compared to the baseline. Agricultural production drops too, but less so in the “R&D investment” scenario due to productivity gains resulting from the increased R&D spending. In some countries, the productivity gains totally offset the negative impact of liberalisation on agricultural production. Smaller agricultural production implies less agricultural land use, and the more so in the “R&D Investment” scenario where productivity increases. The fall in agricultural production and prices negatively affects economic activity and households’ purchasing power, but the reduced direct taxation compensates this effect and results in a GDP gain of 0.53% and 0.8 million additional jobs. In “R&D investment” GDP gain reaches 2.57% and yields 2.95 million additional jobs in EU in 2025. The GDP, consumption and employment gains in the “R&D Investment” scenario widely exceed the losses in the agriculture sectors. The analysis indicates that if no external effects of agriculture are considered, then the CAP is an inefficient use of tax money, and that a considerable contribution to reaching the goals of the Lisbon agenda would be achieved if the same amount of money was instead invested in R&D.CAP reform, economical growth, land use, Agricultural and Food Policy, Land Economics/Use,

    Atom cooling and trapping by disorder

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    We demonstrate the possibility of three-dimensional cooling of neutral atoms by illuminating them with two counterpropagating laser beams of mutually orthogonal linear polarization, where one of the lasers is a speckle field, i.e. a highly disordered but stationary coherent light field. This configuration gives rise to atom cooling in the transverse plane via a Sisyphus cooling mechanism similar to the one known in standard two-dimensional optical lattices formed by several plane laser waves. However, striking differences occur in the spatial diffusion coefficients as well as in local properties of the trapped atoms.Comment: 11 figures (postscript

    Static and Dynamic Properties of Dissipative Particle Dynamics

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    The algorithm for the DPD fluid, the dynamics of which is conceptually a combination of molecular dynamics, Brownian dynamics and lattice gas automata, is designed for simulating rheological properties of complex fluids on hydrodynamic time scales. This paper calculates the equilibrium and transport properties (viscosity, self-diffusion) of the thermostated DPD fluid explicitly in terms of the system parameters. It is demonstrated that temperature gradients cannot exist, and that there is therefore no heat conductivity. Starting from the N-particle Fokker-Planck, or Kramers' equation, we prove an H-theorem for the free energy, obtain hydrodynamic equations, and derive a non-linear kinetic equation (the Fokker-Planck-Boltzmann equation) for the single particle distribution function. This kinetic equation is solved by the Chapman-Enskog method. The analytic results are compared with numerical simulations.Comment: 22 pages, LaTeX, 3 Postscript figure

    Bound and free atoms diagnosed by the recoil-induced resonances: 1D optical lattice in a working MOT

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    We report on studies of simultaneous trapping of 85^{85}Rb atoms in a magneto-optical trap (MOT) and 1D optical lattice. Using Raman pump-probe spectroscopy we observe the coexistence of two atomic fractions: the first, which consists of free, unbound atoms trapped in a MOT and the second, localized in the micropotentials of the optical lattice. We show that recoil-induced resonances allow not only temperature determination of the atomic cloud but, together with vibrational resonances, can also be used for real-time, nondestructive studies of the lattice loading and of the dynamics of systems comprising unbound and bound atomic fractions.Comment: 6 pages, 7 figures, submitted to PR

    Density fluctuations and single-particle dynamics in liquid lithium

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    The single-particle and collective dynamical properties of liquid lithium have been evaluated at several thermodynamic states near the triple point. This is performed within the framework of mode-coupling theory, using a self-consistent scheme which, starting from the known static structure of the liquid, allows the theoretical calculation of several dynamical properties. Special attention is devoted to several aspects of the single-particle dynamics, which are discussed as a function of the thermodynamic state. The results are compared with those of Molecular Dynamics simulations and other theoretical approaches.Comment: 31 pages (in preprint format), 14 figures. Submitted to Phys. Rev.
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