2,103 research outputs found

    The Energy Operator for a Model with a Multiparametric Infinite Statistics

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    In this paper we consider energy operator (a free Hamiltonian), in the second-quantized approach, for the multiparameter quon algebras: aiaj†−qijaj†ai=δij,i,j∈Ia_{i}a_{j}^{\dagger}-q_{ij}a_{j}^{\dagger}a_{i} = \delta_{ij}, i,j\in I with (qij)i,j∈I(q_{ij})_{i,j\in I} any hermitian matrix of deformation parameters. We obtain an elegant formula for normally ordered (sometimes called Wick-ordered) series expansions of number operators (which determine a free Hamiltonian). As a main result (see Theorem 1) we prove that the number operators are given, with respect to a basis formed by "generalized Lie elements", by certain normally ordered quadratic expressions with coefficients given precisely by the entries of the inverses of Gram matrices of multiparticle weight spaces. (This settles a conjecture of two of the authors (S.M and A.P), stated in [8]). These Gram matrices are hermitian generalizations of the Varchenko's matrices, associated to a quantum (symmetric) bilinear form of diagonal arrangements of hyperplanes (see [12]). The solution of the inversion problem of such matrices in [9] (Theorem 2.2.17), leads to an effective formula for the number operators studied in this paper. The one parameter case, in the monomial basis, was studied by Zagier [15], Stanciu [11] and M{\o}ller [6].Comment: 24 pages. accepted in J. Phys. A. Math. Ge

    Experimental Validation of Mathematical Framework for Fast Switching Valves used in Digital Hydraulic Machines

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    A prototype of a fast switching valve designed for a digital hydraulic transmission has been manufactured and experimentally tested. The valve is an annular seat valve composed of a plunger connected with a direct electromagnetic moving coil actuator as the force producing element. Based on an elaborate optimization method the valve is designed to maximize the efficiency of a digital hydraulic motor targeted to a wind turbine transmission system. The optimisation method comprises a mathematical framework which predicts a valve switching time of approximately 1 ms with a peak actuator input power of 10 kW during switching (mean of approximately 250 W) and a pressure loss below 0.5 bar at 600 l/min. The main goal of this article is validate parts of the mathematical framework based on a series of experiments. Furthermore, this article aims to document the experience gained from the experimental work and to study and assess a moving coil actuators suitability for the application.</jats:p

    Unimolecular Reactions Following Indoor and Outdoor Limonene Ozonolysis

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    Limonene is one of the monoterpenes with the largest biogenic emissions and is also widely used as an additive in cleaning products, leading to significant indoor emissions. Studies have found that the formation of secondary organic aerosols (SOAs) from limonene oxidation has important implications for indoor air quality. Although ozonolysis is considered the major limonene oxidation pathway under most indoor conditions, little is known about the mechanisms for SOA formation from limonene ozonolysis. Here, we calculate the rate coefficients of the possible unimolecular reactions of the first-generation peroxy radicals formed by limonene ozonolysis using a high-level multiconformer transition state theory approach. We find that all of the peroxy radicals formed initially in the ozonolysis of limonene react unimolecularly with rates that are competitive both indoors and outdoors, except under highly polluted conditions. Differences in reactivity between the peroxy radicals from ozonolysis and those formed by OH, NO₃, and Cl oxidation are discussed. Finally, we sketch possible oxidation mechanisms for the different peroxy radicals under both indoor and pristine atmospheric conditions and in more polluted environments. In environments with low concentrations of HO₂ and NO, efficient autoxidation will lead to the formation of highly oxygenated organic compounds and thus likely aid in the growth of SOA

    Vitamin K2 Facilitating Inter-Organ Cross-Talk

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    This chapter features how vitamin K2 is instrumental in bringing about inter-organ communication, thus facilitating (a) a synthesis/secretion of the endocrine, humoral factors from various organs and (b) physiological responses to the said factors by a multitude of organ systems of the body, thus creating a ‘lattice’ of reciprocal regulatory loops in order to ensure endocrine homeostasis

    A case study on agreement between self-reported bicycle accidents and hospital and police records

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    A self-report questionnaire on bicycle accidents was distributed to 6,793 respondents every month for one year (2012/2013). This paper evaluates the agreement between hospital data, police data, and self-reports concerning the number of accidents, as well as the information recorded regarding each accident. Six hundred and ninety-four accidents were self-reported by 6,793 respondents. In 99 cases, the respondents reported getting medical care at a hospital. Of these self-reported contacts, 74 could be matched to a hospital record, but only 53 of the 74 were registered in the hospital records as traffic accidents. Information on the primary opposite party in the 53 accidents was compared, and moderate agreement was found between self-reports and hospital records (κ=0.63). In 23 of the self-reported accidents, it was stated that a police report had been recorded, but only 6 accidents could be located in the police records. The sample size was too small to calculate statistical agreement between police records and self-reports. These findings are relevant to discuss of the level of underreporting of bicycle accidents in Denmark because they indicate that there could be substantially more accidents than noted in official records. Furthermore, this paper provides insight into methodological issues associated with self-reporting of traffic accidents

    A case study on agreement between self-reported bicycle accidents and hospital and police records

    Get PDF
    A self-report questionnaire on bicycle accidents was distributed to 6,793 respondents every month for one year (2012/2013). This paper evaluates the agreement between hospital data, police data, and self-reports concerning the number of accidents, as well as the information recorded regarding each accident. Six hundred and ninety-four accidents were self-reported by 6,793 respondents. In 99 cases, the respondents reported getting medical care at a hospital. Of these self-reported contacts, 74 could be matched to a hospital record, but only 53 of the 74 were registered in the hospital records as traffic accidents. Information on the primary opposite party in the 53 accidents was compared, and moderate agreement was found between self-reports and hospital records (κ=0.63). In 23 of the self-reported accidents, it was stated that a police report had been recorded, but only 6 accidents could be located in the police records. The sample size was too small to calculate statistical agreement between police records and self-reports. These findings are relevant to discuss of the level of underreporting of bicycle accidents in Denmark because they indicate that there could be substantially more accidents than noted in official records. Furthermore, this paper provides insight into methodological issues associated with self-reporting of traffic accidents
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