A Nonhorseshoe Template in a Chaotic Laser Model

1998 ◽  
Vol 08 (05) ◽  
pp. 965-975 ◽  
Author(s):  
G. Boulant ◽  
M. Lefranc ◽  
S. Bielawski ◽  
D. Derozier
Keyword(s):  
Topological Analysis ◽  
Experimental Studies ◽  
Experimental System ◽  
Single Mode ◽  
Chaotic Regime ◽  
Chaotic Laser ◽  
Class B ◽  
Laser Model ◽  
The One ◽  
Parameter Values

We have performed a topological analysis of a chaotic regime of a modulated single-mode class-B laser model, at realistic parameter values. In contrast with previous numerical and experimental studies of this type of laser, we observe a topological structure which differs from the one described by the paradigmatic horseshoe template. In view of this result, class-B lasers appear to be good candidates for the first clear characterization of a nonhorseshoe template in an experimental system.

scholarly journals On the Collective Mode Spectrum in FQHE

1998 ◽  
Vol 12 (11) ◽  
pp. 1135-1146
Author(s):  
Alejandro Cabo ◽  
Aurora Pérez Martínez
Keyword(s):  
Collective Mode ◽  
Single Mode ◽  
Mode Spectrum ◽  
Wide Range ◽  
Single Mode Approximation ◽  
Zero Momentum ◽  
The One ◽  
Gap Parameter ◽  
Parameter Values ◽  
Particle Propagator

We consider the Bethe Salpeter Equation (BSE) for a fractionally filled Landau level. A phenomenological discussion of the 1/3 Laughlin's state is performed by assuming an ansatz for the one-particle propagator. The BSE is solved in this approach and it predicts an instability under the formation of charge density oscillations for a wide range of the one-particle gap parameter values in contrast with previous single mode approximation results. However, the conclusion is compatible with the one obtained within a composite fermion description done by us before and with the saturation of the zero momentum oscillator strength sum rule by the cyclotronic resonance. Further studies should be done in order to understand the discrepancy.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

COMPUTATIONAL AND EXPERIMENTAL STUDIES OF A LOW-EMISSION BURNER FOR A PERSPECTIVE TURBOJET ENGINE WITH THE COMPRESSION RATIO EXCEEDING 40

2020 ◽  
Author(s):  
M. A. Danilov ◽  
◽  
M. V. Drobysh ◽  
A. N. Dubovitsky ◽  
F. G. Markov ◽  
...  
Keyword(s):  
Compression Ratio ◽  
Experimental Studies ◽  
The Other ◽  
Aircraft Engines ◽  
Engine Efficiency ◽  
Other Hand ◽  
Turbojet Engine ◽  
Low Emission ◽  
Civil Aircraft ◽  
The One

Restrictions of emissions for civil aircraft engines, on the one hand, and the need in increasing the engine efficiency, on the other hand, cause difficulties during development of low-emission combustors for such engines.

scholarly journals Analytical solution of one-dimensional Pennes’ bioheat equation

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 1084-1092
Author(s):  
Hongyun Wang ◽  
Wesley A. Burgei ◽  
Hong Zhou
Keyword(s):  
Analytical Solution ◽  
Radiofrequency Energy ◽  
Bioheat Equation ◽  
Surface Cooling ◽  
One Dimensional ◽  
The Fourier Transform ◽  
The One ◽  
Parameter Values ◽  
Mathematical Derivation ◽  
Effect Of Surface

Abstract Pennes’ bioheat equation is the most widely used thermal model for studying heat transfer in biological systems exposed to radiofrequency energy. In their article, “Effect of Surface Cooling and Blood Flow on the Microwave Heating of Tissue,” Foster et al. published an analytical solution to the one-dimensional (1-D) problem, obtained using the Fourier transform. However, their article did not offer any details of the derivation. In this work, we revisit the 1-D problem and provide a comprehensive mathematical derivation of an analytical solution. Our result corrects an error in Foster’s solution which might be a typo in their article. Unlike Foster et al., we integrate the partial differential equation directly. The expression of solution has several apparent singularities for certain parameter values where the physical problem is not expected to be singular. We show that all these singularities are removable, and we derive alternative non-singular formulas. Finally, we extend our analysis to write out an analytical solution of the 1-D bioheat equation for the case of multiple electromagnetic heating pulses.

scholarly journals Thermal-stress analysis of a damaged solid sphere using hyperbolic two-temperature generalized thermoelasticity theory

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamdy M. Youssef ◽  
Alaa A. El-Bary ◽  
Eman A. N. Al-Lehaibi
Keyword(s):  
Mechanical Damage ◽  
Generalized Thermoelasticity ◽  
Solid Sphere ◽  
Thermoelasticity Theory ◽  
Mechanical Waves ◽  
Temperature Parameter ◽  
Thermoelastic Solid ◽  
The One ◽  
Parameter Values ◽  
Two Temperature

AbstractThis work aims to study the influence of the rotation on a thermoelastic solid sphere in the context of the hyperbolic two-temperature generalized thermoelasticity theory based on the mechanical damage consideration. Therefore, a mathematical model of thermoelastic, homogenous, and isotropic solid sphere with a rotation based on the mechanical damage definition has been constructed. The governing equations have been written in the context of hyperbolic two-temperature generalized thermoelasticity theory. The bounding surface of the sphere is thermally shocked and without volumetric deformation. The singularities of the studied functions at the center of the sphere have been deleted using L’Hopital’s rule. The numerical results have been represented graphically with various mechanical damage values, two-temperature parameters, and rotation parameter values. The two-temperature parameter has significant effects on all the studied functions. Damage and rotation have a major impact on deformation, displacement, stress, and stress–strain energy, while their effects on conductive and dynamical temperature rise are minimal. The thermal and mechanical waves propagate with finite speeds on the thermoelastic body in the hyperbolic two-temperature theory and the one-temperature theory (Lord-Shulman model).

Analysis of Beam-Like Structures With Displacement-Dependent Friction Forces: Part I — Single-Degree-of-Freedom Model

1995 ◽  
Author(s):  
Wayne E. Whiteman ◽  
Aldo A. Ferri
Keyword(s):  
Dry Friction ◽  
Damping Ratio ◽  
Strong Dependence ◽  
Time Integration ◽  
Single Mode ◽  
Stick Slip ◽  
Friction Forces ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Parameter Values

Abstract The dynamic behavior of a beam-like structure undergoing transverse vibration and subjected to a displacement-dependent dry friction force is examined. In Part I, the beam is modeled by a single mode while Part II considers multi-mode representations. The displacement dependence in each case is caused by a ramp configuration that allows the normal force across the sliding interface to increase linearly with slip displacement. The system is studied first by using first-order harmonic balance and then by using a time integration method. The stick-slip behavior of the system is also studied. Even though the only source of damping is dry friction, the system is seen to exhibit “viscous-like” damping characteristics. A strong dependence of the equivalent natural frequency and damping ratio on the displacement amplitude is an interesting result. It is shown that for a given set of parameter values, an optimal ramp angle exists that maximizes the equivalent damping ratio. The appearance of two dynamic response solutions at certain system and forcing parameter values is also seen. Results suggest that the overall characteristics of mechanical systems may be improved by properly configuring frictional interfaces to allow normal forces to vary with displacement.

Crashworthiness Performance of Mass-Efficient Extruded Structures

2002 ◽  
Author(s):  
Robert R. Mayer ◽  
Weigang Chen ◽  
Anil Sachdev
Keyword(s):  
Numerical Simulations ◽  
Single Cell ◽  
Experimental Testing ◽  
Experimental Studies ◽  
Nonlinear Material ◽  
Dynamic Strain ◽  
Cell Design ◽  
Explicit Finite Element ◽  
The One ◽  
Crushing Behavior

Theoretical, numerical and experimental studies were conducted on the axial crushing behavior of traditional single-cell and innovative four-cell extrusions. Two commercial aluminum alloys, 6061 and 6063, both with two tempers (T4 and T6), were considered in the study. Testing coupons taken from the extrusions assessed the nonlinear material properties. A theoretical solution was available for the one-cell design, and was developed for the mean crushing force of the four-cell section. Numerical simulations were carried out using the explicit finite element code LS-DYNA. The aluminum alloy 6063T4 was found to absorb less energy than 6061T4, for both the one-cell and four-cell configurations. Both 6061 and 6063 in the T6 temper were found to have significant fracture in the experimental testing. Theoretical analysis and numerical simulations predicted a greater number of folds for the four-cell design, as compared to the one-cell design, and this was confirmed in the experiments. The theoretical improvement in energy absorption of 57% for the four-cell in comparison with the one-cell design was confirmed by experiment. The good agreement between the theoretical, numerical and experimental results allows confidence in the application of the theoretical and numerical tools for both single-cell and innovative four-cell extrusions. It was also demonstrated that these materials have very little dynamic strain rate effect.

scholarly journals Signaling pathways have an inherent need for noise to acquire information

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Eugenio Azpeitia ◽  
Eugenio P. Balanzario ◽  
Andreas Wagner
Keyword(s):  
Signaling Pathways ◽  
Information Acquisition ◽  
Cellular Level ◽  
Kinetic Properties ◽  
Positive Role ◽  
Binding Interactions ◽  
Reversible Binding ◽  
Wide Range ◽  
The One ◽  
Parameter Values

Abstract Background All living systems acquire information about their environment. At the cellular level, they do so through signaling pathways. Such pathways rely on reversible binding interactions between molecules that detect and transmit the presence of an extracellular cue or signal to the cell’s interior. These interactions are inherently stochastic and thus noisy. On the one hand, noise can cause a signaling pathway to produce the same response for different stimuli, which reduces the amount of information a pathway acquires. On the other hand, in processes such as stochastic resonance, noise can improve the detection of weak stimuli and thus the acquisition of information. It is not clear whether the kinetic parameters that determine a pathway’s operation cause noise to reduce or increase the acquisition of information. Results We analyze how the kinetic properties of the reversible binding interactions used by signaling pathways affect the relationship between noise, the response to a signal, and information acquisition. Our results show that, under a wide range of biologically sensible parameter values, a noisy dynamic of reversible binding interactions is necessary to produce distinct responses to different stimuli. As a consequence, noise is indispensable for the acquisition of information in signaling pathways. Conclusions Our observations go beyond previous work by showing that noise plays a positive role in signaling pathways, demonstrating that noise is essential when such pathways acquire information.

scholarly journals Plasmodium infection decreases fecundity and increases survival of mosquitoes

2012 ◽  
Vol 279 (1744) ◽  
pp. 4033-4041 ◽  
Author(s):  
J. Vézilier ◽  
A. Nicot ◽  
S. Gandon ◽  
A. Rivero
Keyword(s):  
Life History ◽  
Insecticide Resistance ◽  
Life History Traits ◽  
Experimental System ◽  
Adaptive Strategy ◽  
Genetic Variations ◽  
The Other ◽  
Plasmodium Infection ◽  
Trade Off ◽  
The One

Long-lived mosquitoes maximize the chances of Plasmodium transmission. Yet, in spite of decades of research, the effect of Plasmodium parasites on mosquito longevity remains highly controversial. On the one hand, many studies report shorter lifespans in infected mosquitoes. On the other hand, parallel (but separate) studies show that Plasmodium reduces fecundity and imply that this is an adaptive strategy of the parasite aimed at redirecting resources towards longevity. No study till date has, however, investigated fecundity and longevity in the same individuals to see whether this prediction holds. In this study, we follow for both fecundity and longevity in Plasmodium- infected and uninfected mosquitoes using a novel, albeit natural, experimental system. We also explore whether the genetic variations that arise through the evolution of insecticide resistance modulate the effect of Plasmodium on these two life-history traits. We show that (i) a reduction in fecundity in Plasmodium- infected mosquitoes is accompanied by an increase in longevity; (ii) this increase in longevity arises through a trade-off between reproduction and survival; and (iii) in insecticide-resistant mosquitoes, the slope of this trade-off is steeper when the mosquito is infected by Plasmodium (cost of insecticide resistance).

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