We develop a continuum description for the axial segregation of granular materials in a long rotating drum based on the dynamics of the thin near-surface granular flow coupled to bulk flow. The equations of motion are reduced to the one-dimensional system for two local variables only, the concentration difference and the dynamic angle of repose, or the average slope of the free surface. The par...

in this work, the solubility of nicotine extracted from tobacco leaves, found in the north of iran, in supercritical carbon dioxide has been measured. also the effects of pressure, temperature, extraction dynamic time, and the organic co-solvent on the amount of nicotine extracted from tobacco leaves have been investigated. it should be stressed that in order to reduce significantly the number ...

We derive a stochastic nonlinear continuum equation to describe the morphological evolution of amorphous surfaces eroded by ion bombardment. Starting from Sigmund s theory of sputter erosion, we calculate the coefficients appearing in the continuum equation in terms of the physical parameters characterizing the sputtering process. We analyze the morphological features predicted by the continuum...

We theoretically study time delays obtained using the attosecond-streaking technique. To this end, we compute time delays by numerically solving the corresponding time-dependent Schrödinger equation and analyze the delays using two classical methods, namely, a perturbative approach and a full numerical solution of Newton’s equation describing the motion of the photoelectron in the continuum. A ...

Contents Chapter 1. Introduction 5 1.1. The selective excitation transform 5 1.2. The problem of selective excitation pulse design 6 1.3. Examples 7 1.4. The discrete selective excitation transform (hard pulse approximation) 10 1.5. Main results: continuum theory 11 1.6. Main results: discrete theory 12 1.7. Energy Formulas 13 1.8. Algorithms 13 Chapter 2. Scattering theory 15 2.1. Preliminarie...

efficiency of numerical methods is an important problem in dynamic nonlinear analyses. it is possible to use of numerical methods such as beta-newmark in order to investigate the structural response behavior of the dynamic systems under random sea wave loads but because of necessity to analysis the offshore systems for extensive time to fatigue study it is important to use of simple stable meth...

tension-leg platform (tlp) is a vertically moored floating structure. the platform is permanently mooredby tendons. surge equation of motion of tlp is highly nonlinear because of large displacement and it should be solved with perturbation parameter in time domain. this paper compare the dynamic motion responses of a tlp in regular sea waves obtained by applying three method in time domain usin...

Strain gradient elasticity and nonlocal are two enhanced elastic theories intensively used over the last fifty years to explain static dynamic phenomena that classical fails do. The theory has a clear differentiation from case by considering stresses at point of continuum as an integral defined in treated body. On other hand, strain is characterized non-classical because considers both potentia...

in this article, vibration analysis of an euler-bernoulli beam resting on a pasternak-type foundation is studied. the governing equation is solved by using a spectral finite element model (sfem). the solution involves calculating wave and time responses of the beam. the fast fourier transform function is used for temporal discretization of the governing partial differential equation into a set ...

Contact mechanics is related to the deformation study of solids that meet each other at one or more points. The physical and mathematical formulation of the problem is established upon the mechanics of materials and continuum mechanics and focuses on computations involving bodies with different characteristics in static or dynamic contact. Contact mechanics gives essential information for the s...