scholarly journals Self-diffusion in nanofluids of nonelongated particles in the dilute limit

Author(s):  
P. Fariñas Alvariño ◽  
J. M. Sáiz Jabardo ◽  
L. Cabezas-Gómez

AbstractThe dynamic features of a dilute suspension of nanoparticles (nanofluid) are fully modified depending on the dominant particles slip mechanism acting in the suspension. Self-diffusion effects in highly sheared diluted suspensions (entrance conditions and microapplications) can lead to a particles distribution fully different from the bulk one. The reported investigation proposes a model to determine the self-diffusion of three-planes symmetric nonelongated particles inmersed in a sheared Stokes flow. The model is based on the real displacements between any pair of particles and an statistical approach to determine contact kinematic irreversibilities. According to the proposed model, the source of hydrodynamic irreversibility is closely related to the particles shape. This is clearly demonstrated through the application of the model to cubic particles. The main conclusion is that the particles shape plays a significant role in the dynamic behavior of the suspension and, as a result, in the self-diffusion coefficient. The reported results arising from the cubic particles trajectories in a Stokes flow are reasonably close to the ones reported by Brady and Morris (J Fluid Mech, 348:103–139, 1997) for suspensions under high Pe number, and Zarraga and Leighton (Phys Fluids 13(3):565-577, 2001).

Soft Matter ◽  
2021 ◽  
Author(s):  
Riccardo Artoni ◽  
Michele Larcher ◽  
James T. Jenkins ◽  
Patrick Richard

The self-diffusivity tensor in homogeneously sheared dense granular flows is anisotropic. We show how its components depend on solid fraction, restitution coefficient, shear rate, and granular temperature.


Author(s):  
Victor P. Arkhipov ◽  
Natalia A. Kuzina ◽  
Andrei Filippov

AbstractAggregation numbers were calculated based on measurements of the self-diffusion coefficients, the effective hydrodynamic radii of micelles and aggregates of oxyethylated alkylphenols in aqueous solutions. On the assumption that the radii of spherical micelles are equal to the lengths of fully extended neonol molecules, the limiting values of aggregation numbers corresponding to spherically shaped neonol micelles were calculated. The concentration and temperature ranges under which spherical micelles of neonols are formed were determined.


1989 ◽  
Vol 39 (8) ◽  
pp. 5025-5034 ◽  
Author(s):  
G. Vogl ◽  
W. Petry ◽  
Th. Flottmann ◽  
A. Heiming

1962 ◽  
Vol 36 (9) ◽  
pp. 2410-2414 ◽  
Author(s):  
Shneior Lifson ◽  
Julius L. Jackson

Author(s):  
Xianjie Yang ◽  
Sayed Nassar

In an effort to establish a theoretical outline of a criterion for preventing the vibration-induced loosening of preloaded threaded fasteners, this paper provides an experimental and analytical insight into the effect of the initial bolt preload and the excitation amplitude on the self loosening performance of cap screw fastener. A nonlinear model is used for predicting the clamp load loss caused by the vibration-induced loosening of cap screw fasteners under cyclic transverse loading. Experimental verification was conducted on the twisting torque variation and the effect of the preload level and transverse displacement amplitude. Comparison of the experimental and analytical results on the clamp load loss with the number of cycles verifies that the proposed model accurately predicts self-loosening performance.


2016 ◽  
Vol 30 (01) ◽  
pp. 1550253 ◽  
Author(s):  
Xinjian Liu ◽  
Yu Jin ◽  
Congliang Huang ◽  
Jingfeng He ◽  
Zhonghao Rao ◽  
...  

Temperature and pressure have direct and remarkable implications for drying and dewatering effect of low rank coals such as lignite. To understand the microenergy change mechanism of lignite, the molecular dynamics simulation method was performed to study the self-diffusion of lignite/water under different temperatures and pressure. The results showed that high temperature and high pressure can promote the diffusion of lignite/water system, which facilitates the drying and dewatering of lignite. The volume and density of lignite/water system will increase and decrease with temperature increasing, respectively. Though the pressure within simulation range can make lignite density increase, the increasing pressure showed a weak impact on variation of density.


1959 ◽  
Vol 37 (10) ◽  
pp. 1629-1636 ◽  
Author(s):  
J. R. MacEwan ◽  
J. U. MacEwan ◽  
L. Yaffe

The self-diffusion of nickel and the diffusion of Ni63 into iron, cobalt, and two iron–nickel alloys was studied using the technique of decrease in surface activity, The nickel self-diffusion results are compared to previously reported values. Nickel is found to diffuse more slowly than iron in the iron-rich portion of the iron–nickel system. The rate of nickel diffusion increases with increasing nickel content. A comparison is made between the present results for diffusion of Ni63 into iron, cobalt, and nickel with reported values for diffusion of Co60 and Fe59 in the same metals. In each solvent, the magnitudes of the activation energies, Q, are such that QNi > QCo > QFe.


1983 ◽  
Vol 34 (2) ◽  
pp. 263-269 ◽  
Author(s):  
S. STAUNTON ◽  
P. H. NYE
Keyword(s):  
The Self ◽  

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