نتایج جستجو برای: initial and constant
تعداد نتایج: 16868391 فیلتر نتایج به سال:
This paper presents an evolutionary based method to obtain the un-stressed lattice spacing, d0, required to calculate the residual stress profile across a weld of an age-hardenable aluminum alloy, AA2024. Due to the age-hardening nature of this alloy, the d0 value depends on the heat treatment. In the case of welds, the heat treatment imposed by the welding operation differs significantly depen...
section{introduction} the concept of {sl cartan geometry} appeared at the beginning of the twentieth century, when {e}lie cartan was working on the so-called {sl equivalence problem}, the aim of which is to determine whether two given geometric structures can be mapped bijectively onto each other by some diffeomorphism. this problem can be considered in many different contexts, such as ...
The three-point correlation function of cosmological fluctuations is a sensitive probe of the physics of inflation. We calculate the bispectrum, Bg(k1, k2, k3), Fourier transform of the three-point function of density peaks (e.g., galaxies), using the Matarrese-Lucchin-Bonometto formula. The bispectrum of peaks is not only sensitive to that of the underlying matter density fluctuations, but als...
We study the impact of the QCD DGLAP evolution on the geometric scaling of the gluon distributions which is expected to hold at small x within the saturation models. To this aim we solve the DGLAP evolution equations with the initial conditions provided along the critical line Q2 = Qs(x) with Q 2 s(x) ∼ x and satisfying geometric scaling. Both fixed and running coupling cases are studied. We sh...
Motivated by conventional gauge theories, we consider a theory of gravity in which the Einstein–Hilbert action is replaced by a term that is quadratic in the Riemann tensor. We focus on cosmological solutions to the field equations in flat, open and closed universes. The gravitational action is scale invariant, so the only matter source considered is radiation. The theory can also accommodate i...
Energy estimates show that linearized thermo-elasticity deenes a contraction semi-group on a Hilbert space. We show that under a geometric condition this contraction is not strict, or, more precisely, the norm of the semi group is 1 for all t 0. Convex domains always satisfy the geometric condition. 2. introduction Let R n be a bounded domain with smooth boundary ?. We consider the problem @ 2 ...
The responses of neurons to time-varying injected currents are reproducible on a trial-by-trial basis in vitro, but when a constant current is injected, small variances in interspike intervals across trials add up, eventually leading to a high variance in spike timing. It is unclear whether this difference is due to the nature of the input currents or the intrinsic properties of the neurons. Ne...
The importance of pulse-coupled oscillators (PCOs) in biology and engineering has motivated research to understand basic properties of PCO networks. Despite the large body of work addressing PCOs, a global synchronization result for networks that are more general than all-to-all connected is still unavailable. In this paper we address global synchronization of PCO networks described by cycle gr...
We obtain effective equations of inflationary dynamics for the mean inflaton and metric fields – expectation values in the no-boundary and tunneling quantum states of the Universe. The equations are derived in the slow roll approximation taking the form of the local Schwiger-DeWitt expansion. In this approximation effective equations follow from the Euclidean effective action calculated on the ...
Compartmental epidemiological models have been developed since the 1920s and successfully applied to study the propagation of infectious diseases. Besides, due to their structure, in the 1960s an interesting version of these models was developed to clarify some aspects of rumor propagation, considering that spreading an infectious disease or disseminating information is analogous phenomena. Her...
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