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Inclusive differential cross sections $d\\sigma_{pA}/dx_F$ and $d\\sigma_{pA}/dp_t^2$ for the production of \\kzeros, \\lambdazero, and \\antilambda particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to $\\sqrt {s} = 41.6$ GeV in the proton-nucleon system. The ratios of differential cross sections \\rklpa and \\rllpa are measured to be $6.2\\pm 0.5$ and $0.66\\pm 0.07$, respectively, for \\xf $\\approx-0.06$. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions $d\\sigma_{pA}/dp_t^2$ also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections $\\sigma_{pA}$ on the atomic mass $A$ of the target material is discussed, and the deduced cross sections per nucleon $\\sigma_{pN}$ are compared with results obtained at other energies.

The dynamics of a solid spherical body in an oscillating liquid flow in a vertical axisymmetric channel of variable cross section is experimentally studied. It is shown that the oscillating liquid leads to the generation of intense averaged flows in each of the channel segments. The intensity and direction of these flows depend on the dimensionless oscillating frequency. In the region of studied frequencies, the dynamics of the considered body is examined when the primary vortices emerging in the flow occupy the whole region in each segment. For a fixed frequency, an increase in the oscillation amplitude leads to a phase-inclusion holding effect, i.e., the body occupies a quasi-stationary position in one of the cells of the vertical channel, while oscillating around its average position. It is also shown that the oscillating motion of a liquid column generates an averaged force acting on the body, the magnitude of which depends on the properties of the body and its position in the channel. The quasi-stationary position is determined by the relative density and size of the body, as well as the dimensionless frequency. The behavior of the body as a function of the amplitude and frequency of fluid oscillation and relative size is discussed in detail. Such findings may be used in the future to control the position of a phase inclusion and/or to strengthen mass transfer effects in a channel of variable cross section by means of fluid oscillations.

Rarefied gas flow into a vacuum through short linearly diverging and converging channels has been examined with the direct simulation Monte Carlo method. Solution to the problem has been suggested using complete geometric setup with quite large areas on inlet and outlet of a model channel in examined geometry. A mass flow rate through the channel and flow field both inside the channel and upstream and downstream have been calculated in a wide range of gas rarefaction. These calculation results are comparable to corresponding data for the channel with constant cross section. A strong impact of channel geometry and gas rarefaction has been proved.

In a recent study, the Two-Layer Crossing Channels Micromixer (TLCCM) exhibited good mixing capacities in the case of the Newtonian fluids (close to 100%) for all considered Reynolds number values. However, since the majority of the used fluids in the industrial sectors are non-Newtonians, this work details the mixing evolution of power-law fluids in the considered geometry. In this paper, the power-law index ranges from 0.73 to 1 and the generalized Reynolds number is bounded between 0.1 and 50. The conservation equations of momentum, mass and species transport are numerically solved using a CFD code, considering the species transport model. The flow structure at the cross-sectional planes of our micromixer was studied using the dynamic systems theory. The evolutions of the intensity, also the axial, radial and tangential velocity profiles were examined for different values of the Reynolds number and the power-law index. Besides, the pressure drop of the power-law fluids under different Reynolds number was calculated and represented. Furthermore, the mixing efficiency is evaluated by the computation of the mixing index (MI), based on the standard deviation of the mass fraction in different cross-sections. In such geometry, a perfect mixing is achieved with MI closed to 99.47 %, at very small Reynolds number (from the value 0.1) whatever the power-law index and generalized Reynolds numbers taken in this investigation. Consequently, the targeted channel presents a useful tool for pertinent mass transfer improvements, it is highly recommended to include it in various microfluidic systems.