232 research outputs found
Analytical calculation of slip flow in lattice Boltzmann models with kinetic boundary conditions
We present a mathematical formulation of kinetic boundary conditions for
Lattice Boltzmann schemes in terms of reflection, slip, and accommodation
coefficients. It is analytically and numerically shown that, in the presence of
a non-zero slip coefficient, the Lattice Boltzmann flow develops a physical
slip flow component at the wall. Moreover, it is shown that the slip
coefficient can be tuned in such a way to recover quantitative agreement with
analytical and experimental results up to second order in the Knudsen number.Comment: 27 pages, 4 figure
The Z-index: A geometric representation of productivity and impact which accounts for information in the entire rank-citation profile
We present a simple generalization of Hirsch's h-index, Z =
\sqrt{h^{2}+C}/\sqrt{5}, where C is the total number of citations. Z is aimed
at correcting the potentially excessive penalty made by h on a scientist's
highly cited papers, because for the majority of scientists analyzed, we find
the excess citation fraction (C-h^{2})/C to be distributed closely around the
value 0.75, meaning that 75 percent of the author's impact is neglected.
Additionally, Z is less sensitive to local changes in a scientist's citation
profile, namely perturbations which increase h while only marginally affecting
C. Using real career data for 476 physicists careers and 488 biologist careers,
we analyze both the distribution of and the rank stability of Z with
respect to the Hirsch index h and the Egghe index g. We analyze careers
distributed across a wide range of total impact, including top-cited physicists
and biologists for benchmark comparison. In practice, the Z-index requires the
same information needed to calculate h and could be effortlessly incorporated
within career profile databases, such as Google Scholar and ResearcherID.
Because Z incorporates information from the entire publication profile while
being more robust than h and g to local perturbations, we argue that Z is
better suited for ranking comparisons in academic decision-making scenarios
comprising a large number of scientists.Comment: 9 pages, 5 figure
Towards a mesoscopic model of water-like fluids with hydrodynamic interactions
We present a mesoscopic lattice model for non-ideal fluid flows with
directional interactions, mimicking the effects of hydrogen-bonds in water. The
model supports a rich and complex structural dynamics of the orientational
order parameter, and exhibits the formation of disordered domains whose size
and shape depend on the relative strength of directional order and thermal
diffusivity. By letting the directional forces carry an inverse density
dependence, the model is able to display a correlation between ordered domains
and low density regions, reflecting the idea of water as a denser liquid in the
disordered state than in the ordered one
Effects of Nanoparticles on the Dynamic Morphology of Electrified Jets
We investigate the effects of nanoparticles on the onset of varicose and
whipping instabilities in the dynamics of electrified jets. In particular, we
show that the non-linear interplay between the mass of the nanoparticles and
electrostatic instabilities, gives rise to qualitative changes of the dynamic
morphology of the jet, which in turn, drastically affect the final deposition
pattern in electrospinning experiments. It is also shown that even a tiny
amount of excess mass, of the order of a few percent, may more than double the
radius of the electrospun fiber, with substantial implications for the design
of experiments involving electrified jets as well as spun organic fibers.Comment: 8 pages, 7 figures, 1 tabl
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