1,153 research outputs found
Dynamic mesh refinement for discrete models of jet electro-hydrodynamics
Nowadays, several models of unidimensional fluid jets exploit discrete
element methods. In some cases, as for models aiming at describing the
electrospinning nanofabrication process of polymer fibers, discrete element
methods suffer a non constant resolution of the jet representation. We develop
a dynamic mesh-refinement method for the numerical study of the
electro-hydrodynamic behavior of charged jets using discrete element methods.
To this purpose, we import ideas and techniques from the string method
originally developed in the framework of free-energy landscape simulations. The
mesh-refined discrete element method is demonstrated for the case of
electrospinning applications.Comment: 16 pages, 7 figures in Journal of Computational Science, 201
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
The Practice of Nonviolence: Teaching an Undergraduate Course in Nonviolent Communication
This Best Practices article outlines 10 tips relative to teaching a course in Nonviolent Communication (NVC). It outlines suggestions for readings, activities, and projects throughout a semester-long undergraduate course. The article addresses how students can learn both the theory and practice of nonviolence by means of readings and activities that address social problems such as sexism, racism, bias, and violence against oneself and the earth. Specific suggestions are provided for creative ways in which students can be engaged with readings so that they have ownership of their in-class experience. Details regarding an independent long-term project providing freedom of creativity in out-of-class work are included, as well as suggestions for interactive, face-to-face activities in class
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
Natural and Synthetic Compounds for Management, Prevention and Treatment of Obesity, 2nd Edition
- …