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In this paper we deal with high-order corrections for the Fractional Derivative approach to anomalous diffusion, in super-diffusive regime, which become relevand whenever one attempts to describe the behavior of particles close to normal…

Statistical Mechanics · Physics 2007-06-15 M. Marseguerra , A. Zoia

When considering fractional diffusion equation as model equation in analyzing anomalous diffusion processes, some important parameters in the model, for example, the orders of the fractional derivative or the source term, are often unknown,…

Analysis of PDEs · Mathematics 2019-04-15 Zhiyuan Li , Masahiro Yamamoto

A fractional variational principle was derived in order to be used with lagrangians containing fractional derivatives of order 1/2. By forcing the action associated to this type of lagrangian to be stationary, a modified fractional…

Classical Physics · Physics 2020-01-24 Luis Fernando Mora Mora

Monitoring time-dependence with diffusion MRI yields observables sensitive to compartment sizes (restricted diffusion) and membrane permeability (water exchange). However, restricted diffusion and exchange have opposite effects on the…

In the last two decades, Fresnel diffraction (FD) of a plane wave from phase steps has been systematically studied and applied for precise measurements of light wavelength, and height and refractive index of the step. In this study we…

Optics · Physics 2019-06-13 Masoud Ghoorchi-Beygi , Masoomeh Dashtdar

In this work, an analogue of the Tricomi problem for equations of mixed type with a fractional derivative is investigated. In one part of the domain, the considered equation is a subdiffusion equation with a fractional derivative of order ?…

Analysis of PDEs · Mathematics 2021-03-30 R. R. Ashurov , R. T. Zunnunov

We report new measurements of single particle dispersion in turbulent two-dimensional (2D) flows. Laboratory experiments in electromagnetically driven and Faraday wave driven turbulence reveal a transition from weakly dispersing…

Fluid Dynamics · Physics 2015-06-18 H. Xia , N. Francois , H. Punzmann , M. Shats

We present two observations related to theapplication of linear (LFE) and nonlinear fractional equations (NFE). First, we give the comparison and estimates of the role of the fractional derivative term to the normal diffusion term in a LFE.…

Chaotic Dynamics · Physics 2009-11-07 H. Weitzner , G. M. Zaslavsky

The aim of this paper is the derivation of structure preserving schemes for the solution of the EPDiff equation, with particular emphasis on the two dimensional case. We develop three different schemes based on the Discrete Variational…

Analysis of PDEs · Mathematics 2016-04-26 Stig Larsson , Takayasu Matsuo , Klas Modin , Matteo Molteni

In this paper, we develop an encounter-based model of partial surface adsorption for fractional diffusion in a bounded domain. We take the probability of adsorption to depend on the amount of particle-surface contact time, as specified by a…

Statistical Mechanics · Physics 2023-03-21 Paul C Bressloff

Modeling of phenomena such as anomalous transport via fractional-order differential equations has been established as an effective alternative to partial differential equations, due to the inherent ability to describe large-scale behavior…

Analysis of PDEs · Mathematics 2021-10-25 Jorge Suzuki , Mamikon Gulian , Mohsen Zayernouri , Marta D'Elia

We report experiments on gravity-capillary wave turbulence on the surface of a fluid. The wave amplitudes are measured simultaneously in time and space using an optical method. The full space-time power spectrum shows that the wave energy…

Fluid Dynamics · Physics 2010-10-01 Eric Herbert , Nicolas Mordant , Eric Falcon

Propagation of transient mechanical waves in porous media is numerically investigated in 1D. The framework is the linear Biot's model with frequency-independant coefficients. The coexistence of a propagating fast wave and a diffusive slow…

Geophysics · Physics 2010-05-06 Guillaume Chiavassa , Bruno Lombard , Joël Piraux

The optical reflection coefficient of a dielectric medium moving uniformly in the plane spanned by its surface is rigorously calculated using classical electrodynamics and special relativity, and expressed in the Fourier domain, as a…

We consider a controlled second order differential equation which is partially observed with an additional fractional noise. we study the asymptotic (for large observation time) design problem of the input and give an efficient estimator of…

Probability · Mathematics 2019-04-09 Chunhao Cai , Wujun LV

Employing a phase space which includes the (Riemann-Liouville) fractional derivative of curves evolving on real space, we develop a restricted variational principle for Lagrangian systems yielding the so-called restricted fractional…

Mathematical Physics · Physics 2018-03-01 Fernando Jiménez , Sina Ober-Blöbaum

In this paper we study $g$-fractional diffusion on bounded domains in $\mathbb{R}^d$ with absorbing boundary conditions. We show the explicit representation of the solution and then we study the first passage time distribution, showing the…

Analysis of PDEs · Mathematics 2023-03-09 L. Angelani , R. Garra

We consider a time-independent variable coefficients fractional porous medium equation and formulate an associated inverse problem. We determine both the conductivity and the absorption coefficient from exterior partial measurements of the…

Analysis of PDEs · Mathematics 2023-02-07 Li Li

This letter introduces a formalism for modeling time-variant channels for diffusive molecular communication systems. In particular, we consider a fluid environment where one transmitter nano-machine and one receiver nano-machine are…

Information Theory · Computer Science 2017-03-08 Arman Ahmadzadeh , Vahid Jamali , Adam Noel , Robert Schober

A fractional diffusion equation based on Riemann-Liouville fractional derivatives is solved exactly. The initial values are given as fractional integrals. The solution is obtained in terms of $H$-functions. It differs from the known…

Statistical Mechanics · Physics 2007-05-23 R. Hilfer