23,746 research outputs found

    Cycled operation of water vapor electrolysis cell Annual report, 1 Jan. - 31 Dec. 1969

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    Mathematical model of heat, mass, and momentum relationships in cyclic operation of water vapor electrolytic cell, and equilibrium conditions between gel matrix and vapo

    Some Methods for Assessing the Need for Non-linear Models in Business Cycle Analysis and Forecasting

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    There is a long tradition in business cycle analysis of arguing that non-linear models are needed to explain the business cycle. In recent years many non-linear models have been fitted to data on GDP for many countries, but particularly for the U.S. In this paper we set our criteria to evaluate the success of non-linear models in explaining the cycle and then evaluate three recent models in the light of these criteria. We find that the models are capable of explaining the "shape" of expansions, something linear models cannot do, but do so at the cost of making expansions longer than they should be and in producing transition probabilities to recessions that are too low.business cyles, non-linear models

    Impact of Uncertainties in Hadron Production on Air-Shower Predictions

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    At high energy, cosmic rays can only be studied by measuring the extensive air showers they produce in the atmosphere of the Earth. Although the main features of air showers can be understood within a simple model of successive interactions, detailed simulations and a realistic description of particle production are needed to calculate observables relevant to air shower experiments. Currently hadronic interaction models are the main source of uncertainty of such simulations. We will study the effect of using different hadronic models available in CORSIKA and CONEX on extensive air shower predictions.Comment: 12 pages, 6 figures, to appear in the proceedings of International Conference on Interconnection between High Energy Physics and Astroparticle Physics: From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 Sep 200

    Effective Operators for Double-Beta Decay

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    We use a solvable model to examine double-beta decay, focusing on the neutrinoless mode. After examining the ways in which the neutrino propagator affects the corresponding matrix element, we address the problem of finite model-space size in shell-model calculations by projecting our exact wave functions onto a smaller subspace. We then test both traditional and more recent prescriptions for constructing effective operators in small model spaces, concluding that the usual treatment of double-beta-decay operators in realistic calculations is unable to fully account for the neglected parts of the model space. We also test the quality of the Quasiparticle Random Phase Approximation and examine a recent proposal within that framework to use two-neutrino decay to fix parameters in the Hamiltonian. The procedure eliminates the dependence of neutrinoless decay on some unfixed parameters and reduces the dependence on model-space size, though it doesn't eliminate the latter completely.Comment: 10 pages, 8 figure

    Hadronic multiparticle production in extensive air showers and accelerator experiments

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    Using CORSIKA for simulating extensive air showers, we study the relation between the shower characteristics and features of hadronic multiparticle production at low energies. We report about investigations of typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers. Possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed.Comment: To be published in Proceedings of ICRC 2005, 29th International Cosmic Ray Conferenc

    Monte-Carlo simulations of photohadronic processes in astrophysics

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    A new Monte Carlo program for photohadronic interactions of relativistic nucleons with an ambient photon radiation field is presented. The event generator is designed to fulfil typical astrophysical requirements, but can also be used for radiation and background studies at high energy colliders such as LEP2 and HERA, as well as for simulations of photon induced air showers. We consider the full photopion production cross section from the pion production threshold up to high energies. It includes resonance excitation and decay, direct single pion production and diffractive and non-diffractive multiparticle production. The cross section of each individual process is calculated by fitting experimental data, while the kinematics is determined by the underlying particle production process. We demonstrate that our model is capable of reproducing known accelerator data over a wide energy range.Comment: 39 pages, 17 figures, submitted to Comp.Phys.Co
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