922 research outputs found
Thermodynamics of the FRW universe at the event horizon in Palatini f(R) gravity
In an accelerated expanding universe, one can expect the existence of an
event horizon. It may be interesting to study the thermodynamics of the
Friedmann-Robertson-Walker (FRW) universe at the event horizon. Considering the
usual Hawking temperature, the first law of thermodynamics does not hold on the
event horizon. To satisfy the first law of thermodynamics, it is necessary to
redefine Hawking temperature. In this paper, using the redefinition of Hawking
temperature and applying the first law of thermodynamics on the event horizon,
the Friedmann equations are obtained in f(R) gravity from the viewpoint of
Palatini formalisn. In addition, the generalized second law (GSL) of
thermodynamics, as a measure of the validity of the theory, is investigated
Uncertainty quantification of microstructure-governed properties of polysilicon MEMS
In this paper, we investigate the stochastic effects of the microstructure of polysilicon films on the overall response of microelectromechanical systems (MEMS). A device for on-chip testing has been purposely designed so as to maximize, in compliance with the production process, its sensitivity to fluctuations of the microstructural properties; as a side effect, its sensitivity to geometrical imperfections linked to the etching process has also been enhanced. A reduced-order, coupled electromechanical model of the device is developed and an identification procedure, based on a genetic algorithm, is finally adopted to tune the parameters ruling microstructural and geometrical uncertainties. Besides an initial geometrical imperfection that can be considered specimen-dependent due to its scattering, the proposed procedure has allowed identifying an average value of the effective polysilicon Young's modulus amounting to 140 GPa, and of the over-etch depth with respect to the target geometry layout amounting to O = -0.09 µm. The procedure has been therefore shown to be able to assess how the studied stochastic effects are linked to the scattering of the measured input-output transfer function of the device under standard working conditions. With a continuous trend in miniaturization induced by the mass production of MEMS, this study can provide information on how to handle the foreseen growth of such scattering
Modification of Truncated Expansion Method for Solving Some Important Nonlinear Partial Differential Equations
In this paper, we implemented modification of truncated expansion method for the exact solutions of the Konopelchenko-Dubrovsky equation the (n+1)-dimensional combined sinhcosh- Gordon equation and the Maccari system. Modification of truncated expansion method is a powerful solution method for obtaining exact solutions of nonlinear evolution equations. This method presents a wider applicability for handling nonlinear wave equations
Analytic Investigation of the KP-Joseph-Egri Equation for Traveling Wave Solutions
By means of the two distinct methods, the cosine-function method and the (G /G ) expansion method, we successfully performed an analytic study on the KP-Joseph-Egri (KP-JE) equation. We exhibited its further closed form traveling wave solutions which reduce to solitary and periodic waves
Exact solutions of the Kudryashov–Sinelshchikov equation and nonlinear telegraph equation via the first integral method
In this article we find the exact traveling wave solutions of the Kudryashov–Sinelshchikov equation and nonlinear telegraph equation by using the first integral method. This method is based on the theory of commutative algebra. This method can be applied to nonintegrable equations as well as to integrable ones
Exact Travelling Wave Solutions for Konopelchenko-Dubrovsky Equation by the First Integral Method
In this paper, the first integral method is used to construct exact travelling wave solutions of Konopelchenko-Dubrovsky equation. The first integral method is algebraic direct method for obtaining exact solutions of nonlinear partial differential equations. This method can be applied to non-integrable equations as well as to integrable ones. This method is based on the theory of commutative algebra
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