Dynamics of bead formation, filament thinning and breakup in weakly viscoelastic jets

2010 ◽  
Vol 665 ◽  
pp. 46-56 ◽  
Author(s):  
A. M. ARDEKANI ◽  
V. SHARMA ◽  
G. H. McKINLEY
Keyword(s):  
Temporal Evolution ◽  
Relative Magnitude ◽  
Ohnesorge Number ◽  
Physical Processes ◽  
Spatiotemporal Evolution ◽  
One Dimensional ◽  
Elastic Stresses ◽  
Low Viscosity ◽  
String Structure ◽  
Nonlinear Free Surface

The spatiotemporal evolution of a viscoelastic jet depends on the relative magnitude of capillary, viscous, inertial and elastic stresses. The interplay of capillary and elastic stresses leads to the formation of very thin and stable filaments between drops, or to ‘beads-on-a-string’ structure. In this paper, we show that by understanding the physical processes that control different stages of the jet evolution it is possible to extract transient extensional viscosity information even for very low viscosity and weakly elastic liquids, which is a particular challenge in using traditional rheometers. The parameter space at which a forced jet can be used as an extensional rheometer is numerically investigated by using a one-dimensional nonlinear free-surface theory for Oldroyd-B and Giesekus fluids. The results show that even when the ratio of viscous to inertio-capillary time scales (or Ohnesorge number) is as low as Oh ~ 0.02, the temporal evolution of the jet can be used to obtain elongational properties of the liquid.

Super Accelerated Flow in Diverging Conical Pipes

2011 ◽  
Vol 110-116 ◽  
pp. 880-885
Author(s):  
G.J. Gutierrez ◽  
A. López Villa ◽  
A. Torres ◽  
S. Peralta ◽  
C. A. Vargas
Keyword(s):  
Free Surface ◽  
Free Fall ◽  
Liquid Column ◽  
Dimensional Model ◽  
One Dimensional ◽  
Low Viscosity ◽  
Accelerated Flow ◽  
Theoretical Results

The motion of the upper free surface of a liquid column released from rest in a vertical, conical container is analyzed theoretically and experimentally. An inviscid, one-dimensional model, for a slightly expanding pipe's radius, describes how the recently reported super free fall of liquids occurs in liquids of very low viscosity. Experiments agree with the theoretical results.

ROBUSTNESS OF COMPLETE STABILITY FOR 1-D CIRCULAR CNNs

2006 ◽  
Vol 16 (08) ◽  
pp. 2177-2190
Author(s):  
MAURO DI MARCO ◽  
CHIARA GHILARDI
Keyword(s):  
Neural Networks ◽  
Equilibrium Point ◽  
Nearest Neighbor ◽  
Perturbation Parameter ◽  
Relative Magnitude ◽  
Loss Of Stability ◽  
Unique Equilibrium ◽  
Small Perturbations ◽  
Structure Preserving ◽  
One Dimensional

This paper investigates the issue of robustness of complete stability of standard Cellular Neural Networks (CNNs) with respect to small perturbations of the nominally symmetric interconnections. More specifically, a class of circular one-dimensional (1-D) CNNs with nearest-neighbor interconnections only, is considered. The class has sparse interconnections and is subject to perturbations which preserve the interconnecting structure. Conditions assuring that the perturbed CNN has a unique equilibrium point at the origin, which is unstable, are provided in terms of relative magnitude of the perturbations with respect to the nominal interconnection weights. These conditions allow one to characterize regions in the perturbation parameter space where there is loss of stability for the perturbed CNN. In turn, this shows that even for sparse interconnections and structure preserving perturbations, robustness of complete stability is not guaranteed in the general case.

Automatic Texture Based Classification of the Dynamics of One-Dimensional Binary Cellular Automata

2019 ◽  
Vol 8 (4) ◽  
pp. 41-61
Author(s):  
Marcelo Arbori Nogueira ◽  
Pedro Paulo Balbi de Oliveira
Keyword(s):  
Cellular Automata ◽  
Dynamic Behavior ◽  
Temporal Evolution ◽  
Computational Cost ◽  
Great Variability ◽  
Texture Descriptor ◽  
One Dimensional ◽  
Binary Images ◽  
Elementary Cellular Automata

Cellular automata present great variability in their temporal evolutions due to the number of rules and initial configurations. The possibility of automatically classifying its dynamic behavior would be of great value when studying properties of its dynamics. By counting on elementary cellular automata, and considering its temporal evolution as binary images, the authors created a texture descriptor of the images - based on the neighborhood configurations of the cells in temporal evolutions - so that it could be associated to each dynamic behavior class, following the scheme of Wolfram's classic classification. It was then possible to predict the class of rules of a temporal evolution of an elementary rule in a more effective way than others in the literature in terms of precision and computational cost. By applying the classifier to the larger neighborhood space containing 4 cells, accuracy decreased to just over 70%. However, the classifier is still able to provide some information about the dynamics of an unknown larger space with reduced computational cost.

scholarly journals Substrate stiffness induced mechanotransduction regulates temporal evolution of human fetal neural progenitor cell phenotype, differentiation, and biomechanics

2020 ◽  
Vol 8 (19) ◽  
pp. 5452-5464
Author(s):  
Chandrasekhar Kothapalli ◽  
Gautam Mahajan ◽  
Kurt Farrell
Keyword(s):  
Mechanical Properties ◽  
Stem Cells ◽  
Neural Stem Cells ◽  
Progenitor Cell ◽  
Temporal Evolution ◽  
Neural Progenitor Cell ◽  
Neural Progenitor ◽  
Substrate Stiffness ◽  
Cell Phenotype ◽  
Spatiotemporal Evolution

We here report on the substrate stiffness dependent spatiotemporal evolution of mechanical properties of neural stem cells and their progenies.

A first attempt to model an Artificial Ice Reservoir (Ice Stupa) using a simple energy balance approach

2020 ◽  
Author(s):  
Suryanarayanan Balasubramanian ◽  
Martin Hoelzle ◽  
Michael Lehning ◽  
Sonam Wangchuk ◽  
Johannes Oerlemans ◽  
...  
Keyword(s):  
Water Mass ◽  
Meteorological Data ◽  
Physical Processes ◽  
Discharge Data ◽  
One Dimensional ◽  
Vapour Diffusion ◽  
Alternate Model ◽  
Energy Balance Approach ◽  
Fresh Water Resource ◽  
Model Scenarios

<div> <div> <p>Artificial Ice Reservoirs (AIRs, also called icestupas) have been successful in storing water during winter and releasing the water during spring and summer. Therefore, they can be seen as a vital fresh water resource for irrigation in dry environments. Many different forms of AIRs do exist and not many studies have tried to model theses ice structures.<br>We will present simulations of the most important physical processes that causes the formation and melt of AIRs using one dimensional equations governing the heat transfer, vapour diffusion and water transport of a phase changing water mass. For validation, an AIR was constructed in Schwarzsee region in the Canton of Fribourg, Switzerland. Meteorological data in conjunction with fountain discharge data was measured. According to the model, the Schwarzsee AIR was able to store and discharge 850 litres or  3.7 percent of all the water sprayed over a duration of 41 days. Alternate model scenarios will also be presented to show how this freezing efficiency can be increased.</p> </div> </div>

Effects on electrostatic fields excited by radio-frequency waves in a bounded plasma due to the ponderomotive force

1992 ◽  
Vol 47 (2) ◽  
pp. 271-279
Author(s):  
C. R. Gutiérrez-Tapia
Keyword(s):  
Radio Frequency ◽  
Driving Forces ◽  
Ponderomotive Force ◽  
Plasma Layer ◽  
Physical Processes ◽  
One Dimensional ◽  
Electrostatic Fields ◽  
Bounded Plasma ◽  
Linearly Polarized ◽  
Radio Frequency Waves

A one-dimensional model explaining the mechanism of excitation of electrostatic fields by linearly polarized radio-frequency waves in a plasma layer is presented. It is shown that the ponderomotive and driving forces influence this process strongly; however, these forces act at different times when a wave front passes through the plasma. We consider a semi-infinite plasma, and a plasma layer with and without current. It is observed that near to the plasma boundaries, where the electric field is large, there arise amplitude field oscillations, which are slowly exponentially damped in space. It is shown that the physical processes arising near the boundary x = L are similar to those at the boundary x = 0. It is seen that the current in the plasma block excitation at the boundary x = L.

scholarly journals Scattered Packet Method for the Simulation of the Spatio-temporal Evolution of Local Perturbations

VLSI Design ◽  
2001 ◽  
Vol 13 (1-4) ◽  
pp. 205-209 ◽  
Author(s):  
P. Gaubert ◽  
L. Varani ◽  
J. C. Vaissière ◽  
J. P. Nougier ◽  
E. Starikova ◽  
...  
Keyword(s):  
Temporal Evolution ◽  
Microscopic Level ◽  
Spatiotemporal Evolution ◽  
Noise Sources ◽  
Type Silicon ◽  
Local Perturbations ◽  
Submicron Structures ◽  
Spatio Temporal ◽  
P Type

To calculate the noise in submicron structures we need the knowledge of the local noise sources and the generalised impedance fields. The scattered packet method has been used to obtain both quantities at the same microscopic level. Numerical procedures used for the calculation of velocity and energy noise sources and the simulation of the spatiotemporal evolution of local perturbations introduced on velocity or energy are described and some results obtained for p-type silicon are given.

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