Effects of high hydrostatic pressure on secondary structure and emulsifying behavior of sweet potato protein

In this study, secondary structures of sweet potato protein (SPP) after high hydrostatic pressure (HHP) treatment (200–600?MPa) were evaluated and emulsifying properties of emulsions with HHP-treated SPP solutions in different pH values (3, 6, and 9) were investigated. Circular dichroism analysis confirmed the modification of the SPP secondary structure. Surface hydrophobicity increased at pH 3 and decreased at 6 and 9. Emulsifying activity index at pH 6 increased with an increase in pressure, whereas emulsifying stability index increased at pH 6 and 9. Oil droplet sizes decreased, while volume frequency distribution of the smaller droplets increased at pH 3 and 6 with the HHP treatment. Emulsion viscosity increased at pH 6 and 9 and pseudo-plastic flow behaviors were not altered for all emulsions produced with HHP-treated SPP. These results suggested that HHP could modify the SPP structure for better emulsifying properties, which could increase the use of SPP emulsion in the food industry.     

Rotating flow of a third grade fluid in a porous space with Hall current

This study investigates the rotating magnetohydrodynamic (MHD) flow of a third-grade fluid in a porous space. Modified Darcy's law has been utilized for the flow modeling. The Hall effects are taken into consideration. The basic equations governing the flow are reduced to a highly nonlinear ordinary differential equation. This equation has been solved analytically by employing the homotopy analysis method (HAM). The effects of the various interesting parameters on the velocity distribution have been discussed.     

Vortex generating jets; effects of jet-hole inlet geometry

An experimental study of flow downstream of round, pitched and skewed wall-jets (vortex generating jets) is presented to illustrate the effects of changing the geometric inlet conditions of the jet-holes. In one case the jet-hole has a smoothly contoured inlet, and in the other the inlet was a sharp-edged, sudden contraction. The test region geometry, mean jet flow and cross-flow conditions were otherwise identical. In both cases, dominant streamwise vortex structures are seen in the boundary layer downstream; the flow and turbulence is nearly the same in the far-field starting downstream of x/D=5. In the near-field, for x/D<5, there are significant differences; turbulence levels are higher, and the start of the dominant vortex shape is less clear for the sharp-edged case. This is believed to be the result of flow separation and free shear layer instability inside the jet-hole which are not present for the smoothly contoured case.     

On the use of electrical-resistance metallic foil strain gages for measuring large dynamic plastic deformation

The use of electrical-resistance metallic foil strain gages for measuring large plastic strain in dynamic experiments in studied. The maximum nominal strains obtained in this investigation are 35 percent in compression, 25 percent in tension. A linear variation of gage factor with strain is found in this range. The corrected maximum strains are in excellent agreement with permanent strains measured after the tests. Thus foil strain gages can be effectively used to measure the large dynamic plastic strains.     

Effects due to body-forces and body-couples in the interior of a micropolar elastic half-space—I

A general solution of the equilibrium equations is obtained for a half-space with a fixed boundary and arbitrary but axisymmetric distribution of body forces and body couples in the interior of the half-space. Few particular cases have been investigated in detail. The stresses have been obtained at the boundary and the displacements have been obtained in the interior of the half-space. Numerical results have been displayed graphically.

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Zusammenfassung Eine allgemeine lösung für Gleichgewicht eines Halbraums mit festem Rand und einer beliebigen, aber antisymmetrischen Verteilung von Körperkräften und Körpermomenten im Inneren wird gefunden. Einige Spezialfälle wurden ansführlich erforscht. Die Spannungen am Rand und die Verschiebungen im Inneren des Halbraums wurden erhalten. Numerische Resultate wurden graphisch dargestellt.

     

Transient flows of a second grade fluid

Exact analytical solutions for a class of unsteady unidirectional flows of an incompressible second-order fluid are constructed. The flows are generated impulsively from rest by motion of a plate or two plates or by sudden application of a pressure gradient. Expressions for velocity, flux and skin friction are obtained for both large and small times. It is found that large and small times solutions are dependent on the coefficient of viscoelasticity. The solutions corresponding to Newtonian fluids can be easily obtained from those for fluids of second order by letting the viscoelastic parameter to be zero.     

The influence of Hall current on the rotating oscillating flows of an Oldroyd-B fluid in a porous medium

In this article, analysis is presented to study the effect of Hall current on the rotating flow of a non-Newtonian fluid in a porous medium taking into consideration the modified Darcy's law. The Oldroyd-B fluid model is used to characterize the non-Newtonian fluid behavior. The governing equations for unsteady rotating flow have been modeled in a porous medium. The analysis includes the flows induced by general periodic oscillations and elliptic harmonic oscillations of a plate. The effect of the various emerging parameters is discussed on the velocity distribution. The analytical results are confirmed mathematically by giving comparison with previous studies in the literature. It is observed that the velocity distribution increases with an increase of Hall parameter. The behavior of permeability is similar to that of the Hall parameter.