Hydrodynamic mechanism

The retention of fillers in the sheet during the forming process is important. Both hydrodynamic mechanisms and colloidal or coflocculation phenomena are significant in determining filler retention (7). Polymeric retention aids are used to bridge between filler particles and fibers. Talc is sometimes used with mechanical pulp furnishes in order to reduce the deposition of pitch-like materials onto paper machinery. 

Fito, P., Andres, A., Chiralt, A., and Pardo, P. 1996. Coupling of hydrodynamic mechanism and deformation-relaxation phenomena during vacuum treatments in solid porous food-liquid systems. J. Food Engineer. 27, 229-240. 

Numerous atomization techniques have evolved for the production of metal/alloy powders or as a step in spray forming processes. Atomization of melts may be achieved by a variety of means such as aerodynamic, hydrodynamic, mechanical, ultrasonic, electrostatic, electromagnetic, or pressure effect, or a combination of some of these effects. Some of the atomization techniques have been extensively developed and applied to commercial productions, including (a) two-fluid atomization using gas, water, or oil (i.e., gas atomization, water atomization, oil atomization), (b) vacuum atomization, and (c) rotating electrode atomization. Two-fluid atomization... 

It is also demonstrated that the simultaneous numerical solution by a difference scheme of both the transport and hydrodynamic mechanisms is probably impossible, but that the separate considerations of these two regimes, which is possible, can be connected in a physically reasonable manner... 

While the static equilibrium behavior of polymer blends in thin film geometry thus is rather well understood, at least in principle, the kinetic behavior (Sects. 2.8,3.3) is much less well understood, since there is a delicate interplay between surface-directed spinodal decomposition, thickness-limited growth of wetting layers, and the hydrodynamic mechanisms of coarsening in this constrained geometry still needs investigation. 

Hydrodynamic mechanisms are those which produce particle interactions through the surrounding fluid due to hydrodynamic forces and the asymmetry of the flow field around each particle. These mechanisms, which are not dependent on the relative differences in acoustic particle entrainments, can act from distances larger than the acoustic displacement and have to be considered as the main mechanism in the agglomeration of monodispersed aerosols, where particles are equally entrained. There are two main types of hydrodynamic mechanisms, namely mutual radiation pressure [50] and the acoustic wake effect [51,52]. The radiation pressure is a second-order effect which produces a force on a particle immersed in an acoustic field due to the transfer of momentum from the acoustic wave to the particle. This force moves the particles towards the pressure node or antinode planes of the applied standing wave, depending on the size and density of the particles. The mutual radial pressure can be computed from the primary wave as well as from other wave fields of nearby scatters. In fact, it gives rise to particle interactions as the result of forces produced on two adjacent particles by a non-linear combination of incident and scattered waves. 

Hinze, J. O., (1955), Fundamentals of the hydrodynamic mechanism of splitting in dispersion processes, AIChEJl,pp. 269-295. 

Effective rates of sorption, especially in subsurface systems, are frequently controlled by rates of solute transport rather than by intrinsic sorption reactions perse. In general, mass transport and transfer processes operative in subsurface environments may be categorized as either macroscopic or microscopic. Macroscopic transport refers to movement of solute controlled by movement of bulk solvent, either by advection or hydrodynamic (mechanical) dispersion. For distinction, microscopic mass transfer refers to movement of solute under the influence of its own molecular or mass distribution (Weber et al., 1991). 

The thermochemical conversion of biomass involves a series of different processes where hydrodynamic, mechanical, physical, and chemical phenomena are to be considered. It is therefore almost impossible to deal with the whole process without making drastic assumptions in order to reduce the high number of parameters in play. Unfortunately, these simplifications greatly affect the reliability of the modeling to predict the behavior of the thermochemical conversion of biomass, and its capability to contribute to the understanding of biomass thermal processing. 

Hinze JO (1955) Pundamentals of the Hydrodynamic Mechanism of Splitting in Dispersion Processes. AIChE J l(3) 289-295... 

The role of intercellular space and capillary flow in osmotic dehydration was well documented by Hto et al. [51-53]. On this basis the nondiffusional mass transfer model was developed incorporating hydrodynamic mechanism (HDM). Studies done by the same group [19,54] showed that long time of osmotic process is needed to obtain a fully developed water and sugar concentration profiles. A model based on the advancing disturbance front (ADF) was proposed that allows prediction of sample concentration during osmotic dehydration. 

As early as the 1930s Kuhn [101] had suggested that the solvent inside the polymer coil is immobilized, which means = 0. Flory [14] adopted it as a postulate in formulating his pioneering theory of polymer solutions summarized in his 1953 book [1]. However, unless the hydrodynamic mechanism responsible for this postulate is clarified, we cannot say that eq 3.2 has been explained by molecular theory. It is amazing that we are still unable to explain why actual polymer molecules behave as if non-draining for any chain length. 

Karimi A, Yazdi S, Ardekani AM (2013) Hydrodynamic mechanisms of cell and particle trapping in microfluidics. Biomicrofluidics 7(2) 021501... 

Menet, J.-M. Shimomiya, K. Ito, Y. Studies on new crossaxis coil planet centrifuge for performing counter-current chromatography III. Speculations on the hydrodynamic mechanism in stationary phase retention. J. Chromatogr. 1993, 644, 239. 

Hydrodynamic mechanism in mixer-settier spirai channei... 

In the case of Brownian particles detachment by the hydrodynamic mechanism is not possible due to the much higher values of critical shear stress required for release [120]. For colloidally induced release, in the absence of an energy barrier, the rate of particle detachment is based on the assumption that the rate-limiting step is the diffusion of detached colloids across... 

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