79 research outputs found
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
Non-linear Langevin model for the early-stage dynamics of electrospinning jets
We present a non-linear Langevin model to investigate the early-stage
dynamics of electrified polymer jets in electrospinning experiments. In
particular, we study the effects of air drag force on the uniaxial elongation
of the charged jet, right after ejection from the nozzle. Numerical simulations
show that the elongation of the jet filament close to the injection point is
significantly affected by the non-linear drag exerted by the surrounding air.
These result provide useful insights for the optimal design of current and
future electrospinning experiments.Comment: 11 pages, 6 figures, 1 table. arXiv admin note: text overlap with
arXiv:1503.0469
Data-driven filtering for linear systems using Set Membership multistep predictors
This paper presents a novel data-driven, direct filtering approach for
unknown linear time-invariant systems affected by unknown-but-bounded
measurement noise. The proposed technique combines independent multistep
prediction models, identified resorting to the Set Membership framework, to
refine a set that is guaranteed to contain the true system output. The filtered
output is then computed as the central value in such a set. By doing so, the
method achieves an accurate output filtering and provides tight and minimal
error bounds with respect to the true system output. To attain these results,
the online solution of linear programs is required. A modified filtering
approach with lower online computational cost is also presented, obtained by
moving the solution of the optimization problems to an offline preliminary
phase, at the cost of larger accuracy bounds. The performance of the proposed
approaches are evaluated and compared with those of standard model-based
filtering techniques in a numerical example
Different regimes of the uniaxial elongation of electrically charged viscoelastic jets due to dissipative air drag
We investigate the effects of dissipative air drag on the dynamics of
electrified jets in the initial stage of the electrospinning process. The main
idea is to use a Brownian noise to model air drag effects on the uniaxial
elongation of the jets. The developed numerical model is used to probe the
dynamics of electrified polymer jets at different conditions of air drag force,
showing that the dynamics of the charged jet is strongly biased by the presence
of air drag forces. This study provides prospective beneficial implications for
improving forthcoming electrospinning experiments.Comment: 12 pages, 6 figure
JETSPIN: a specific-purpose open-source software for simulations of nanofiber electrospinning
We present the open-source computer program JETSPIN, specifically designed to
simulate the electrospinning process of nanofibers. Its capabilities are shown
with proper reference to the underlying model, as well as a description of the
relevant input variables and associated test-case simulations. The various
interactions included in the electrospinning model implemented in JETSPIN are
discussed in detail. The code is designed to exploit different computational
architectures, from single to parallel processor workstations. This paper
provides an overview of JETSPIN, focusing primarily on its structure, parallel
implementations, functionality, performance, and availability.Comment: 22 pages, 11 figures. arXiv admin note: substantial text overlap with
arXiv:1507.0701
Regularized lattice Boltzmann Multicomponent models for low Capillary and Reynolds microfluidics flows
We present a regularized version of the color gradient lattice Boltzmann (LB)
scheme for the simulation of droplet formation in microfluidic devices of
experimental relevance. The regularized version is shown to provide
computationally efficient access to Capillary number regimes relevant to
droplet generation via microfluidic devices, such as flow-focusers and the more
recent microfluidic step emulsifier devices.Comment: 9 pages, 5 figure
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