in order to provide the data needed for the design of saffron processing equipment, physical properties of its flower were investigated. these properties included dimensions, mass, true and bulk densities, porosity, static and dynamic coefficients of friction, and terminal velocity as a function of moisture content. the average range of these properties for the three different parts of saff...

in the computational fluid dynamics (cfd) modeling of gas-solids two phase flow, the effect of boundary conditions play an important role in predicting the hydrodynamic characteristics of fluidized beds. in this work, the hydrodynamics of conical fluidized bed containing dried tio2 nano-agglomerates were studied both experimentally and computationally. the pressure drop was obtained by pressure...

In the computational fluid dynamics (CFD) modeling of gas-solids two phase flow, the effect of boundary conditions play an important role in predicting the hydrodynamic characteristics of fluidized beds. In this work, the hydrodynamics of conical fluidized bed containing dried TiO2 nano-agglomerates were studied both experimentally and computationally. The pressure drop ...

This paper presents an experimental research on the distribution of local friction factor, fb, and global friction factor, f, over the cross-section of a channel with V-shaped bottom, which typically occurs in sewers and culverts. Several series of experiments were conducted for measuring velocity and boundary shear stress. It is found that, Darcy-Weisbach, f, is more sensitive than other resis...

Abstract This paper presents a heuristic friction compensation approach for handling the rolling friction behaviors of ball-screw-driven stages in the zero-velocity crossing regions including non-velocity-reversal motion. The rolling friction behaves in a nonlinear way, and would significantly deteriorate the control performance. Since the alteration of elastic energy in mechanical components o...

The velocity and stress autocorrelation decay in a dissipative particle dynamics ideal fluid model is analyzed in this paper. The autocorrelation functions are calculated at three different friction parameters and three different time steps using the well-known Groot/Warren algorithm and newer algorithms including self-consistent leap-frog, self-consistent velocity Verlet and Shardlow first and...

The non-linear dependence of pre-sliding and sliding friction forces on displacement and velocity is modelled using different physics-based and black-box approaches including various Maxwell-Slip models, neural networks, nonparametric (local) models and recurrent networks. The efficiency and accuracy of these identification methods is compared for an experimental time series where the observed ...

A friction identification method in a frequency domain is proposed for a precision servomechanism. A nonlinear friction model including static, Coulomb, and viscous friction as well as Stribeck effect is considered in this paper. Friction models are formulated by using describing functions. Friction elements are estimated through the limit cycle analysis in a velocity control loop. A Butterwort...

The subloading-friction model is capable of describing static friction, the smooth transition from static to kinetic friction and the recovery to static friction after sliding stops or sliding velocity decreases. This causes a negative rate sensitivity (i.e. a decrease in friction resistance with increasing sliding velocity). A generalized subloading-friction model is formulated in this article...

in this study, some seed physical properties of two sugar beet varieties, shirin and gadouk (436), were evaluated as a function of moisture content. physical properties included length, width, thickness, arithmetic and geometric mean diameters, sphericity, thousand seed weight, angle of repose, terminal velocity, true density, bulk density, porosity, and coefficient of friction. four moisture c...