scholarly journals Elasticity of connected semiflexible quadrilaterals

Soft Matter ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 102-112
Author(s):  
Mohammadhosein Razbin ◽  
Alireza Mashaghi
Keyword(s):  
Thermal Fluctuations ◽  
Analytic Expressions ◽  
Probability Densities

The analytic expressions for the probability densities associated with the thermal fluctuations and the elasticity of the structure are obtained.

scholarly journals Thermodynamics of the Schwarzschild-AdS Black Hole with a Minimal Length

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Yan-Gang Miao ◽  
Yu-Mei Wu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Free Energy ◽  
Gibbs Free Energy ◽  
Mass Density ◽  
Minimal Length ◽  
Hydrogen Atoms ◽  
Analytic Expressions ◽  
Probability Densities ◽  
Fractional Function

Using the mass-smeared scheme of black holes, we study the thermodynamics of black holes. Two interesting models are considered. One is the self-regular Schwarzschild-AdS black hole whose mass density is given by the analogue to probability densities of quantum hydrogen atoms. The other model is the same black hole but whose mass density is chosen to be a rational fractional function of radial coordinates. Both mass densities are in fact analytic expressions of the δ-function. We analyze the phase structures of the two models by investigating the heat capacity at constant pressure and the Gibbs free energy in an isothermal-isobaric ensemble. Both models fail to decay into the pure thermal radiation even with the positive Gibbs free energy due to the existence of a minimal length. Furthermore, we extend our analysis to a general mass-smeared form that is also associated with the δ-function and indicate the similar thermodynamic properties for various possible mass-smeared forms based on the δ-function.

A theory of incoherent scattering of radio waves by a plasma II. Scattering in a magnetic field

1961 ◽  
Vol 263 (1313) ◽  
pp. 238-258 ◽  
Keyword(s):  
Magnetic Field ◽  
Frequency Spectrum ◽  
Exact Result ◽  
Thermal Fluctuations ◽  
Scattered Signal ◽  
Radio Waves ◽  
Doppler Shifts ◽  
Analytic Expressions ◽  
Nyquist Noise ◽  
The Magnetic Field

A general expression for the frequency spectrum of radio waves scattered by the random thermal fluctuations of electron density in a plasma in a magnetic field is derived. The derivation is based on the generalized Nyquist noise theorem used in part I. The exact result is then; simplified by means of an approximation which amounts to assuming the velocity of light to be infinite. It is shown that this approximation is quite adequate for ionospheric applications of the theory. Next it is proved, without appealing to any approximation, that the magnetic held can never alter the total scattered signal power; it can only redistribute this power over the spectrum. Finally, the detailed shape of the frequency spectrum of the scattered signal is examined. Analytic expressions are given for certain limiting cases, but for the cases of most interest, numerical methods must be used. The results of some numerical calculations are shown in figures 1 and 2. From these results, it can be seen that the magnetic field has a significant effect on the shape of the spectrum only if the incident radio beam is very nearly orthogonal to the magnetic lines of force. For example, for an operating frequency of 40 Mc/s, no significant magnetic effect is observed even when the beam is within 5 of orthogonality. As this angle is decreased further, however, the spectrum rapidly begins to develop spikes at Doppler shifts which are approximate multiples of the ion gyro-frequency. These spikes are quite pronounced when the beam is 2° from orthogonality. At higher operating frequencies, the beam must be proportionally closer to orthogonality to achieve the same effect.

CNN performance dependence on linear image processing

2020 ◽  
Vol 2020 (10) ◽  
pp. 310-1-310-7
Author(s):  
Khalid Omer ◽  
Luca Caucci ◽  
Meredith Kupinski
Keyword(s):  
Image Processing ◽  
Texture Classification ◽  
Full Rank ◽  
Detection Performance ◽  
Ideal Observer ◽  
Training Data ◽  
Image Texture ◽  
Training Images ◽  
Analytic Expressions ◽  
Linear Compression

This work reports on convolutional neural network (CNN) performance on an image texture classification task as a function of linear image processing and number of training images. Detection performance of single and multi-layer CNNs (sCNN/mCNN) are compared to optimal observers. Performance is quantified by the area under the receiver operating characteristic (ROC) curve, also known as the AUC. For perfect detection AUC = 1.0 and AUC = 0.5 for guessing. The Ideal Observer (IO) maximizes AUC but is prohibitive in practice because it depends on high-dimensional image likelihoods. The IO performance is invariant to any fullrank, invertible linear image processing. This work demonstrates the existence of full-rank, invertible linear transforms that can degrade both sCNN and mCNN even in the limit of large quantities of training data. A subsequent invertible linear transform changes the images’ correlation structure again and can improve this AUC. Stationary textures sampled from zero mean and unequal covariance Gaussian distributions allow closed-form analytic expressions for the IO and optimal linear compression. Linear compression is a mitigation technique for high-dimension low sample size (HDLSS) applications. By definition, compression strictly decreases or maintains IO detection performance. For small quantities of training data, linear image compression prior to the sCNN architecture can increase AUC from 0.56 to 0.93. Results indicate an optimal compression ratio for CNN based on task difficulty, compression method, and number of training images.

Thermal fluctuations of non-motile magnetotactic bacteria in AC magnetic fields

2008 ◽  
Vol 44 (3) ◽  
pp. 223-236 ◽  
Author(s):  
K. Ērglis ◽  
L. Alberte ◽  
A. Cēbers
Keyword(s):  
Magnetic Fields ◽  
Magnetotactic Bacteria ◽  
Thermal Fluctuations

Casimir forces and vacuum energy

2017 ◽  
Author(s):  
Serge Reynaud ◽  
Astrid Lambrecht
Keyword(s):  
Casimir Force ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Model Systems ◽  
Vacuum Field ◽  
Force Measurements ◽  
Casimir Forces ◽  
Current State ◽  
Field Fluctuations

The Casimir force is an effect of quantum vacuum field fluctuations, with applications in many domains of physics. The ideal expression obtained by Casimir, valid for perfect plane mirrors at zero temperature, has to be modified to take into account the effects of the optical properties of mirrors, thermal fluctuations, and geometry. After a general introduction to the Casimir force and a description of the current state of the art for Casimir force measurements and their comparison with theory, this chapter presents pedagogical treatments of the main features of the theory of Casimir forces for one-dimensional model systems and for mirrors in three-dimensional space.

The Fluctuating Lattice Boltzmann

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Brownian Motion ◽  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Thermal Fluctuations ◽  
Directed Motion ◽  
Statistical Fluctuations ◽  
Lattice Boltzmann Models ◽  
Motion Versus ◽  
The Way

Fluid flow at nanoscopic scales is characterized by the dominance of thermal fluctuations (Brownian motion) versus directed motion. Thus, at variance with Lattice Boltzmann models for macroscopic flows, where statistical fluctuations had to be eliminated as a major cause of inefficiency, at the nanoscale they have to be summoned back. This Chapter illustrates the “nemesis of the fluctuations” and describe the way they have been inserted back within the LB formalism. The result is one of the most active sectors of current Lattice Boltzmann research.

scholarly journals POSSIBILITY OF FORMING A LARGE DCC IN ULTRA-RELATIVISTIC HEAVY-ION COLLISIONS

2000 ◽  
Vol 15 (15) ◽  
pp. 2269-2288
Author(s):  
SANATAN DIGAL ◽  
RAJARSHI RAY ◽  
SUPRATIM SENGUPTA ◽  
AJIT M. SRIVASTAVA
Keyword(s):  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Heavy Ion ◽  
High Energy ◽  
Chiral Condensate ◽  
Relativistic Heavy Ion Collisions ◽  
Maximum Temperature ◽  
Chiral Field ◽  
Heavy Nuclei ◽  
True Vacuum

We demonstrate the possibility of forming a single, large domain of disoriented chiral condensate (DCC) in a heavy-ion collision. In our scenario, rapid initial heating of the parton system provides a driving force for the chiral field, moving it away from the true vacuum and forcing it to go to the opposite point on the vacuum manifold. This converts the entire hot region into a single DCC domain. Subsequent rolling down of the chiral field to its true vacuum will then lead to emission of a large number of (approximately) coherent pions. The requirement of suppression of thermal fluctuations to maintain the (approximate) coherence of such a large DCC domain, favors three-dimensional expansion of the plasma over the longitudinal expansion even at very early stages of evolution. This also constrains the maximum temperature of the system to lie within a window. We roughly estimate this window to be about 200–400 MeV. These results lead us to predict that extremely high energy collisions of very small nuclei (possibly hadrons) are better suited for observing signatures of a large DCC. Another possibility is to focus on peripheral collisions of heavy nuclei.

scholarly journals Thermal fluctuations in nuclear pasta

2021 ◽  
Vol 103 (5) ◽  
Author(s):  
M. E. Caplan ◽  
C. R. Forsman ◽  
A. S. Schneider
Keyword(s):  
Thermal Fluctuations
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