81 research outputs found

    The effects of nonlocality on the evolution of higher order fluxes in non-equilibrium thermodynamics

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    The role of gradient dependent constitutive spaces is investigated on the example of Extended Thermodynamics of rigid heat conductors. Different levels of nonlocality are developed and the different versions of extended thermodynamics are classified. The local form of the entropy density plays a crucial role in the investigations. The entropy inequality is solved under suitable constitutive assumptions. Balance form of evolution equations is obtained in special cases. Closure relations are derived on a phenomenological level.Comment: 16 pages, 1 figur

    Covariant description of kinetic freeze out through a finite space-like layer

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    The problem of Freeze Out (FO) in relativistic heavy ion reactions is addressed. We develop and analyze an idealized one-dimensional model of FO in a finite layer, based on the covariant FO probability. The resulting post FO phase-space distributions are discussed for different FO probabilities and layer thicknesses.Comment: 16 pages, 19 figures, changed content, references adde

    Variational and Potential Formulation for Stochastic Partial Differential Equations

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    There is recent interest in finding a potential formulation for Stochastic Partial Differential Equations (SPDEs). The rationale behind this idea lies in obtaining all the dynamical information of the system under study from one single expression. In this Letter we formally provide a general Lagrangian formalism for SPDEs using the Hojman et al. method. We show that it is possible to write the corresponding effective potential starting from an s-equivalent Lagrangean, and that this potential is able to reproduce all the dynamics of the system, once a special differential operator has been applied. This procedure can be used to study the complete time evolution and spatial inhomogeneities of the system under consideration, and is also suitable for the statistical mechanics description of the problem. Keywords: stochastic partial differential equations, variational formulation, effective potential. PACS: 45.20.Jj; 02.50.-r; 02.50.Ey.Comment: Letter, 4 pages, no figures; v2: references added, minor change

    Impact of Nucleon Mass Shift on the Freeze Out Process

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    The freeze out of a massive nucleon gas through a finite layer with time-like normal is studied. The impact of in-medium nucleon mass shift on the freeze out process is investigated. A considerable modification of the thermodynamical variables temperature, flow-velocity, energy density and particle density has been found. Due to the nucleon mass shift the freeze out particle distribution functions are changed noticeably in comparison with evaluations, which use vacuum nucleon mass.Comment: submitted to Physical Review

    Covariant description of kinetic freeze out through a finite time-like layer

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    The Freeze Out (FO) problem is addressed for a covariant FO probability and a finite FO layer with a time-like normal vector continuing the line of studies introduced in Ref. [1]. The resulting post FO momentum distribution functions are presented and discussed. We show that in general the post FO distributions are non-thermal and asymmetric distributions even for time-like FO situations.Comment: 10 pages, 12 figures, major rewrite with changed content, corrected typos and new references adde

    Evolutionary and socio-cultural influences on feelings and attitudes towards nature: a cross-cultural study

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    Mounting environmental issues have prompted reconsideration of the human–nature relationship. Accordingly, attitudes to nature, as an important dimension of human–nature interactions, have become a research focus. How feelings and attitudes towards nature are influenced by evolutionary and social-cultural constructions, and whether there is variation between different cultural groups, demands more attention. Using a survey of visitors to two very different National Parks, the New Forest National Park, England and Jiuzhaigou Scenic Area, China, this paper shows that of nationality and living environment, differences between the two nationalities were significant in respect of both attitudes and feelings. Specifically, it demonstrates that the biophilia thesis, which purports that people have an innate and a genetically inherited need for affiliation with nature, is influenced by their socio-cultural environment, in particular their national culture, but also by their current living place. The study contributes to our understanding of sustainable tourism in natural areas
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