1,008 research outputs found

    Tradable SO-2-permits in the European Union: a practicable scheme for public utilities

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    In this paper, a practicable scheme of SO2-emission permits for European power producers is developed. Background is the second UN-ECE Sulphur Protocol from 1994 (Protocol of Oslo). After discussing some theoretical models of spatially differentiated permit schemes, evaluating the U.S. Acid Rain and RECLAIM Program, and considering the setting in the EU-15 countries, a scheme of locally undifferentiated emission permits is proposed which is distinguished by a high degree of both economic efficiency and market functioning. However, as our model simulations indicate, national deposition targets will be violated in all probability due to the scheme?s missing differentiation regarding the receptors. The risk of hot spots is addressed adequately by a differentiated bundle of countermeasures. The general economic impact of an EU-wide permit scheme is low, and, in terms of change in GDP, lower compared to a non-coordinated SO2 policy. The proposed mode of the initial permit allocation allows for early price signals and guarantees maximum static and dynamic efficiency. Balancing the interests of existing and new emitters, a long-term transition from the grandfathering to the free auction procedure is chosen. --

    Tradable SO2-Permits in the European Union: A Practicable Scheme for Public Utilities

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    In this paper, a practicable scheme of SO2-emission permits for European power producers is developed. Background is the second UN-ECE Sulphur Protocol from 1994 (Protocol of Oslo). After discussing some theoretical models of spatially differentiated permit schemes, evaluating the U.S. Acid Rain and RECLAIM Program, and considering the setting in the EU-15 countries, a scheme of locally undifferentiated emission permits is proposed which is distinguished by a high degree of both economic efficiency and market functioning. However, as our model simulations indicate, national deposition targets will be violated in all probability due to the scheme’s missing differentiation regarding the receptors. The risk of hot spots is addressed adequately by a differentiated bundle of countermeasures. The general economic impact of an EU-wide permit scheme is low, and, in terms of change in GDP, lower compared to a non-coordinated SO2 policy. The proposed mode of the initial permit allocation allows for early price signals and guarantees maximum static and dynamic efficiency. Balancing the interests of existing and new emitters, a long-term transition from the grandfathering to the free auction procedure is chosen

    Reliability and Latency Analysis for Wireless Communication Systems with a Secret-Key Budget

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    We consider a wireless communication system with a passive eavesdropper, in which a transmitter and legitimate receiver generate and use key bits to secure the transmission of their data. These bits are added to and used from a pool of available key bits. In this work, we analyze the reliability in terms of the probability that the budget of available key bits will be exhausted. In addition, we investigate the latency before a transmission can take place. Since security, reliability, and latency are three important metrics for modern communication systems, it is of great interest to jointly analyze them in relation to the system parameters. Interestingly, we show under what conditions the system may remain in an active state indefinitely, i.e., never run out of available secret-key bits. The results presented in this work can be used by system designers to adjust the system parameters in such a way that the requirements of the application in terms of both reliability and latency are met.Comment: 26 pages, 6 figure

    Atomic layer deposition-based tuning of the pore size in mesoporous thin films studied by in situ grazing incidence small angle x-ray scattering

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    Atomic layer deposition (ALD) enables the conformal coating of porous materials, making the technique suitable for pore size tuning at the atomic level, e.g., for applications in catalysis, gas separation and sensing. It is, however, not straightforward to obtain information about the conformality of ALD coatings deposited in pores with diameters in the low mesoporous regime (< 10 nm). In this work, it is demonstrated that in situ synchrotron based grazing incidence small angle x-ray scattering (GISAXS) can provide valuable information on the change in density and internal surface area during ALD of TiO2 in a porous titania film with small mesopores (3-8 nm). The results are shown to be in good agreement with in situ x-ray fluorescence data representing the evolution of the amount of Ti atoms deposited in the porous film. Analysis of both data sets indicates that the minimum pore diameter that can be achieved by ALD is determined by the size of the Ti-precursor molecule

    Heating in the Accreted Neutron Star Ocean: Implications for Superburst Ignition

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    We perform a self-consistent calculation of the thermal structure in the crust of a superbursting neutron star. In particular, we follow the nucleosynthetic evolution of an accreted fluid element from its deposition into the atmosphere down to a depth where the electron Fermi energy is 20 MeV. We include temperature-dependent continuum electron capture rates and realistic sources of heat loss by thermal neutrino emission from the crust and core. We show that, in contrast to previous calculations, electron captures to excited states and subsequent gamma-emission significantly reduce the local heat loss due to weak-interaction neutrinos. Depending on the initial composition these reactions release up to a factor of 10 times more heat at densities < 10^{11} g/cc than obtained previously. This heating reduces the ignition depth of superbursts. In particular, it reduces the discrepancy noted by Cumming et al. between the temperatures needed for unstable 12C ignition on timescales consistent with observations and the reduction in crust temperature from Cooper pair neutrino emission.Comment: 10 pages, 11 figures, the Astrophysical Journal, in press (scheduled for v. 662). Revised from v1 in response to referee's comment
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