排序方式： 共有23条查询结果，搜索用时 15 毫秒
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Amaral Genilda Canuto Pezzopane José Eduardo Macedo de Souza Nóia Júnior Rogério Martínez Manuel Fernández Fonseca Mariana Duarte Silva Gibson Elbya Leão Toledo João Vitor Pezzopane José Ricardo Macedo Klippel Valéria Hollunder Xavier Talita Miranda Teixeira 《Theoretical and Applied Climatology》2022,147(1-2):347-361
Theoretical and Applied Climatology - The climate change endangers many species of the Amazon Forest. An example, in the endangered medicinal species Pilocarpus microphyllus (popularly known as... 相似文献
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We have studied a neutrally-stratified flow over two-dimensional hills using a two-dimensional, non-hydrostatic version of the Regional Atmospheric Modeling System (RAMS). We have implemented three different turbulence closure models: the standardE- model, an Algebraic Reynolds Stress Model (ARSM) and a new
model. Model predictions for the mean and turbulence flows using different closure schemes are compared with the data of a wind tunnel experiment containing isolated two-dimensional hills of varying slope. From the comparison, it is concluded that all three models predict the mean flow velocities equally well while only the new
closure model accurately predicts the turbulence data statistics.The research reported in this paper was conducted while the first author held a National Research Council (NRC) Associateship. 相似文献
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The neutrino luminosity by the ordinary URCA process in a strongly magnetized electron gas is computed. General formulae are presented for the URCA energy loss rates for an arbitrary degree of degeneracy. Analytic expressions are derived for a completely degenerate, relativistic electron plasma in the special case of neutron-proton conversion. Numerical results are given for more general cases.The main results are as follows: the URCA energy loss rates are drastically reduced for the regime of great degeneracy by a factor up to 10–3 for 1, andT
910, where =H/H
q
,H
q
=m
2
c
3/eh=4.414×1013 G. In the non-degenerate regime the neutrino luminosity is enhanced approximately linearly with for the temperature range 1T
910. Possible applications to white dwarfs and neutron stars are briefly discussed.We have been recently informed that in Gamow home-dialect (Odessa dialect) URCA means thief — (Private communication from Prof. G. Wataghin). 相似文献
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The structure of a hydrogen atom situated in an intense magnetic field is investigated. Three approaches are employed. An elementary Bohr picture establishes a crucial magnetic field strength,H a ?5×109G. Fields in excess ofH a are intense in that they are able to modify the characteristic atomic scales of length and binding energy. A second approach solves the Schrödinger equation by a combination of variational methods and perturbation theory. It yields analytic expressions for the wave functions and energy eigenvalues. A third approach determines the energy eigenvalues by reducing the Schrödinger equation to a one-dimensional wave equation, which is then solved numerically. Energy eigenvalues are tabulated for field strengths of 2×1010G and 2×1012 G. It is found that at 2×1012 G the lowest energy eigenvalue is changed from ?13.6 eV to about ?180 eV in agreement with previous variational computations. 相似文献
17.
In this paper we have rederived the equations of state for a magnetized Fermi gas by generalizing the physical definition of the pressure. We have also given a simplified derivation of the energy eigenvalues of a free electron in a magnetic field, based on the use of simple harmonic oscillators. Physical interpretations of our results are presented. Possible astrophysical applications are also discussed.On leave of absence from Dept. of Physics, C.I.E.A., Ap. Post. 14740, Mexico 14, D.F., Mexico. 相似文献
18.
V. M. Canuto 《Monthly notices of the Royal Astronomical Society》2000,317(4):985-988
Schwarzschild first suggested that the laminar structures observed in the high Reynolds number Re UL ν ≈O (1012 ) solar photosphere are the result of turbulence rather than a proof of its absence. He reasoned that, since turbulence generates large turbulent viscosities ν t ≫ ν , the 'effective' Reynolds number Re UL ν t ≈O(1). Schwarzschild's argument is, however, incomplete, for it assumes that the entire role of the non-linear interactions is to 'enhance' viscosity. While this is not true in general, we present a proof of how and why it may occur, thus completing Schwarzschild's argument. We further discuss the fact that the same non-local turbulence models reproduce Large Eddy Simulation (LES) data for a variety of flows pertaining to astrophysics, geophysics and laboratory situations (in a fraction of the time). 相似文献
19.
After reviewing the outer and central regions of a neutron star, we discuss the central region and the possibility that the core has a solid structure. We present the work of different groups on the solidification problem, suggesting that the neutron star-cores are indeed solid. 相似文献
20.
Turbulence modelling over two-dimensional hills using an Algebraic Reynolds Stress Expression 总被引：1，自引：1，他引：0
We carry out model studies of turbulence quantities for flow over two-dimensional hills using a non-hydrostatic version of the Regional Atmospheric Modeling System (RAMS). We test two turbulence closure models: the first one is an explicit Algebraic Reynolds Stress Model (ARSM) and the second one is a combination of the ARSM and a transport equation for the shear stress {ovuw}. Model predictions for the turbulent stresses are compared with data from a wind-tunnel experiment containing isolated two-dimensional hills of varying slope. From the comparison, it is concluded that the first model can only predict the normal stresses adequately while the second model provides satisfactory predictions for the normal stresses as well as giving an improved result for the shear stress {ovuw}. 相似文献