ASYMMETRIC CELLS AND ROTATING RINGS IN CELLULAR FLAMES

1996 ◽  
Vol 10 (28) ◽  
pp. 1379-1387 ◽  
Author(s):  
GEMUNU H. GUNARATNE ◽  
MOHAMED EL-HAMDI ◽  
MICHAEL GORMAN ◽  
KAY A. ROBBINS
Keyword(s):  
Theoretical Model ◽  
Normal Form ◽  
Theoretical Analysis ◽  
Circular Domain ◽  
Experimental Results ◽  
Premixed Flame ◽  
Polar Coordinates ◽  
Cellular Flames ◽  
Pattern Forming ◽  
Parity Breaking

Theoretical analysis and experimental results are presented to demonstrate the universal characteristics of parity-breaking bifurcations for pattern-forming systems in a circular domain. Ordered patterns of concentric rings of cells which form in a premixed flame on a circular burner at low pressure are used to demonstrate these ideas. Cells belonging to stationary rings are symmetric, while those of rotating rings are not. The important characteristics of the experimental results are reproduced in a theoretical model which can be numerically integrated in polar coordinates. Normal form equations for the Fourier–Bessel coefficients of this model lead to parity breaking.

BIFURCATION ANALYSIS OF HOPPING BEHAVIOR IN CELLULAR PATTERN-FORMING SYSTEMS

2007 ◽  
Vol 17 (02) ◽  
pp. 509-520 ◽  
Author(s):  
ANTONIO PALACIOS ◽  
PETER BLOMGREN ◽  
SCOTT GASNER
Keyword(s):  
Steady State ◽  
Normal Form ◽  
Bifurcation Analysis ◽  
Decomposition Analysis ◽  
Circular Domain ◽  
Cellular Pattern ◽  
Mode Decomposition ◽  
Symmetry Properties ◽  
Spatio Temporal ◽  
Pattern Forming

We use symmetry-based arguments to derive normal form equations for studying the temporal behavior of a particular spatio-temporal dynamic cellular pattern, called "hopping" state, which we have recently discovered in computer simulations of a generic example of an extended, deterministic, pattern-forming system in a circular domain. Hopping states are characterized by cellular structures that sequentially make abrupt changes in their angular positions while they rotate, collectively, about the center of the circular domain. A mode decomposition analysis suggests that these patterns are created from the interaction of three steady-state modes. A bifurcation analysis of associated normal form equations, which govern the time-evolution of the steady-state modes, helps us quantify the complexity of hopping patterns. Conditions for their existence and their stability are also derived from the bifurcation analysis. The overall ideas and methods are generic, so they can be readily applied to study other type of spatio-temporal pattern-forming dynamical systems with similar symmetry properties.

scholarly journals Evaluation of the deformation shape of a balloon-type dielectric elastomer actuator prestretched with water pressure

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Natsumi Koike ◽  
Takeshi Hayakawa
Keyword(s):  
Theoretical Model ◽  
Theoretical Analysis ◽  
Good Accuracy ◽  
Water Pressure ◽  
Dielectric Elastomer ◽  
Experimental Results ◽  
Dielectric Elastomer Actuator ◽  
Elastomeric Material ◽  
Mechanical Models ◽  
Applicable Range

AbstractIn this study, we evaluated the deformation shape of a balloon-type dielectric elastomer actuator (DEA) that has been prestretched with water pressure. We fabricated the DEA with poly(dimethylsiloxane) (PDMS) as the elastomeric material and carbon grease as the electrode. We derived analytical solutions for the deformation of the DEA based on structural mechanical models. Additionally, we compared the deformation shapes obtained by theoretical analysis and experimental results. Our model can partially predict the deformation shape of the DEA with good accuracy. In addition, we discuss the applicable range of the theoretical model and error relative to the experimental results.

scholarly journals Fractal Derivative Model for Air Permeability in Hierarchic Porous Media

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jie Fan ◽  
Jihuan He
Keyword(s):  
Porous Media ◽  
Theoretical Model ◽  
Theoretical Analysis ◽  
Air Permeability ◽  
Experimental Results ◽  
The Novel ◽  
Geometric Properties ◽  
Fractal Derivative ◽  
Derivative Method ◽  
First Time

Air permeability in hierarchic porous media does not obey Fick's equation or its modification because fractal objects have well-defined geometric properties, which are discrete and discontinuous. We propose a theoretical model dealing with, for the first time, a seemingly complex air permeability process using fractal derivative method. The fractal derivative model has been successfully applied to explain the novel air permeability phenomenon of cocoon. The theoretical analysis was in agreement with experimental results.

Elastohydrodynamic Film Collapse During Rapid Deceleration. Part II—Theoretical Analysis and Comparison of Theory and Experiment

2000 ◽  
Vol 123 (2) ◽  
pp. 262-267 ◽  
Author(s):  
R. P. Glovnea ◽  
H. A. Spikes
Keyword(s):  
Theoretical Model ◽  
Analytical Solution ◽  
Theoretical Analysis ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Experimental Results ◽  
Rapid Deceleration ◽  
Film Collapse ◽  
Theory And Experiment

This paper presents a theoretical model for the behavior of elastohydrodynamic films subjected to transient speed conditions, based on Grubin’s analytical solution for elastohydrodynamic lubrication. This model is applied to predict film thickness in high deceleration conditions. The model’s predictions are compared with the experimental results presented in an accompanying paper entitled “Elastohydrodynamic Film Collapse During Rapid Deceleration. Part I: Experimental Results.”

Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

2020 ◽  
Vol 14 (4) ◽  
pp. 7396-7404
Author(s):  
Abdul Malek Abdul Wahab ◽  
Emiliano Rustighi ◽  
Zainudin A.
Keyword(s):  
Theoretical Model ◽  
Resonance Frequency ◽  
Dynamic Testing ◽  
Experimental Results ◽  
Percentage Error ◽  
Initial Tension ◽  
Average Percentage ◽  
Soft Actuator ◽  
Average Percentage Error ◽  
Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

scholarly journals A Framework for Modelling Economic Regional Location Processes Under Uncertainty

2021 ◽  
Author(s):  
Roy Cerqueti ◽  
Eleonora Cutrini
Keyword(s):  
Theoretical Model ◽  
Theoretical Analysis ◽  
Site Selection ◽  
Decision Problem ◽  
Stochastic Theory ◽  
Spatial Location ◽  
Probabilistic Framework ◽  
Location Patterns ◽  
Regional Location ◽  
Quantitative Tool

AbstractThis paper deals with the theoretical analysis of the spatial concentration and localization of firms and employees over a set of regions. In particular, it provides a simple site-selection theoretical model to describe the probabilistic framework of the location patterns. The adopted quantitative tool is the stochastic theory of urns. The model moves from the empirical evidence of the deviation of the spatial location of companies from the uniform distribution and of employees from the distribution of firms. Factors leading to such deviations are taken into consideration. Specifically, we formalize a decision problem grounded on the economic attributes of the regions and also on the distribution of the existing firms and employees in the territory. To our purpose, the site-selection model is presented as a stepwise process.

Implementation of a High-Precision Ultrasonic Rain Gauge

2013 ◽  
Vol 300-301 ◽  
pp. 382-388
Author(s):  
Zhan Wei Xu ◽  
Gui Lin Zheng
Keyword(s):  
Theoretical Analysis ◽  
High Precision ◽  
Rain Gauge ◽  
Experimental Results ◽  
Full Description ◽  
Self Calibration ◽  
Velocity Of Ultrasound

A novel rain gauge based on acoustic self-calibration principle is proposed in the paper. Acoustic self-calibration principle can eliminate the uncertainty of the velocity of ultrasound and achieve accurate measurement of rainfall. The rain gauge not only overcomes the influence on the rainfall measurement under intensive rainfall conditions, but also improves the precision of rain gauge. Plenty of experiments have been done to validate the design. Both theoretical analysis and experimental results show the effectiveness of the rain gauge. A full description of the rain gauge and implementation are presented.

scholarly journals New Topologies of Lossless Grounded Inductor Using OTRA

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Rajeshwari Pandey ◽  
Neeta Pandey ◽  
Sajal K. Paul ◽  
A. Singh ◽  
B. Sriram ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Experimental Results ◽  
Pspice Simulation ◽  
Operational Transresistance Amplifier

Two alternate topologies of lossless grounded inductor have been proposed using operational transresistance amplifier (OTRA). Three applications using the proposed inductors are also included. PSPice simulation and experimental results have been included to demonstrate the performance and verify the theoretical analysis.

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