4,748 research outputs found

    Geometry effect of irrigation storage basin on particles removal efficiency: A computational fluid dynamics study

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    Drip irrigation requires the use of high quality water to avoid emitters clogging and the wear of hydraulic pumps and sand filters. Investing in an irrigation storage basin is not only beneficial to meet crop water requirements but also to remove naturally suspended solids by sedimentation. However, the design and sizing of an irrigation storage basin is usually based only on irrigation water needs and plant area without taking into consideration that the shape and size of the basin can also have an effect on the removal efficiency. Moreover, storage volume can be achieved by different combinations of length, width and depth. The present paper studies the effect of irrigation storage basin geometry on its performance in settling down suspended sediments. The methodology adopted in this study is based on the computational fluid dynamics using ANSYS Fluent. Specific experimental results taken from the literature are used to confirm the reliability of the numerical simulations to describe the flow field. First, a parametric study is executed in order to identify the effect of each basin dimensions. Then, trap efficiency is calculated for twenty basins having the same capacity of storage and different geometries in order to select the optimal dimensions. Results show that the removal efficiency is very sensitive to basin size, especially to its depth and length. Nevertheless, for a specific capacity of storage, two different dimensionless parameters can be used to select the optimal size: the length to depth ratio and the length to width ratio. In cases, where the depth value is required due to soil type or land surface, the second ratio can be used

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Compressed representation of a partially defined integer function over multiple arguments

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    In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one
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