scholarly journals Wicking of a liquid bridge connected to a moving porous surface

2012 ◽  
Vol 703 ◽  
pp. 315-325 ◽  
Author(s):  
A. D. Gat ◽  
H. K. Navaz ◽  
M. Gharib
Keyword(s):  
Relative Motion ◽  
Liquid Bridge ◽  
Integral Relation ◽  
Porous Surface ◽  
Opening Angle ◽  
Liquid Penetration ◽  
Coupled Problem ◽  
Arbitrary Cone ◽  
Analytic Expressions ◽  
Theoretical Results

AbstractWe study the coupled problem of a liquid bridge connected to a porous surface and an impermeable surface, where the gap between the surfaces is an externally controlled function of time. The relative motion between the surfaces influences the pressure distribution and geometry of the liquid bridge, thus affecting the shape of liquid penetration into the porous material. Utilizing the lubrication approximation and Darcy’s phenomenological law, we obtain an implicit integral relation between the relative motion between the surfaces and the shape of liquid penetration. A method to control the shape of liquid penetration is suggested and illustrated for the case of conical penetration shapes with an arbitrary cone opening angle. We obtain explicit analytic expressions for the case of constant relative speed of the surfaces as well as for the relative motion between the surfaces required to create conical penetration shapes. Our theoretical results are compared with experiments and reasonable agreement between the analytical and experimental data is observed.

scholarly journals MOVEMENT OF THE PARTICLE ON THE INTERNAL SURFACE OF THE SPHERICAL SEGMENT ROTATING ABOUT A VERTICAL AXIS

2020 ◽  
pp. 79-88
Author(s):  
Sergiy Pylypaka ◽  
Victor Nesvidomin ◽  
Tatiana Volina ◽  
Larysa Sirykh ◽  
Liudmyla Ivashyna
Keyword(s):  
Numerical Methods ◽  
Experimental Research ◽  
Relative Motion ◽  
Particle Motion ◽  
Internal Surface ◽  
Vertical Axis ◽  
Relative Displacement ◽  
Spherical Segment ◽  
Velocity Changes ◽  
Theoretical Results

The particle relative motion on a spherical segment rotating about a vertical axis was considered in the article. The differential equations of the relative displacement of a particle were completed and solved by numerical methods. The relative and absolute trajectories of particle motion and graphs of relative and absolute velocity changes were constructed. The regularity of particle motion as it is lifted over the surface was found out. The conducted experimental research has confirmed the received theoretical results.

Thermal expansion coefficient of BCC defective substitutional alloy AB with interstitial atom C

2019 ◽  
Vol 33 (13) ◽  
pp. 1950165
Author(s):  
Le Thi Cam Tuyen ◽  
Nguyen Quang Hoc ◽  
Bui Duc Tinh ◽  
Pham Thi Minh Hanh ◽  
Tran Dinh Cuong ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Interstitial Atom ◽  
Substitutional Alloy ◽  
Atom Concentration ◽  
Main Metal ◽  
Analytic Expressions ◽  
Substitutional Atom ◽  
Theoretical Results

The analytic expressions for the free energy, the concentration of equilibrium vacancies, the isothermal compressibility, the thermal expansion coefficient and the heat capacities at constant volume and at constant pressure of BCC substitutional alloy AB with interstitial atom C and with vacancy under pressure are derived by the statistical moment method. The theoretical results are applied to the thermal expansion coefficient of alloy FeCrSi in the interval of temperature from 700 K to 1100 K, in the interval of substitutional atom concentration from 0% to 10%, in the interval of interstitial atom concentration from 0% to 5% and in the interval of pressure from 0 GPa to 10 GPa. Our calculated results for main metal Fe are compared with the experimental data.

Theory, numeric, and experiment studies on stability of two homodromy vibrators in a vibrating system with double rigid frames

2020 ◽  
pp. 107754632093818
Author(s):  
Xueliang Zhang ◽  
Zhenmin Li ◽  
Ming Li ◽  
Dawei Gu ◽  
Bangchun Wen
Keyword(s):  
Mathematical Modeling ◽  
Relative Motion ◽  
Average Method ◽  
Stable States ◽  
Dynamical Characteristics ◽  
Rigid Frames ◽  
Motion Characteristics ◽  
Theoretical Results ◽  
Qualitative Analyses ◽  
Vibrating Systems

The synchronization and stability of two or more vibrators in vibrating systems with double rigid frames are rarely investigated in previous studies. To make up this drawback, we take a dynamical model with double rigid frames driven by two homodromy vibrators, for example the synchronous and stable states of the corresponding system, as well as the relative motion characteristics between the two rigid frames, are analyzed in detail. First, the mathematical modeling of the system is given; the absolute motion and relative motion differential equations of the system are deduced. After that, the theory conditions of implementing synchronization and those of stability are obtained, by using the average method and Hamilton’s principle, respectively. Based on the theoretical results, some numerical qualitative analyses are provided to reveal the coupling dynamical characteristics of the system, and the corresponding ideal working regions are suggested. Finally, experiments are carried out to further examine the validity of the theoretical and numerical results. The present work can offer a reference to design some new vibrating machines such as the considered model.

Reinjection Probability Density for Type-III Intermittency With Noise and Lower Boundary of Reinjection

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Sergio Elaskar ◽  
Ezequiel del Rio ◽  
Andrea Costa
Keyword(s):  
Numerical Simulations ◽  
Probability Density ◽  
Noise Intensity ◽  
Lower Boundary ◽  
Nonlinear Behavior ◽  
Exponential Functions ◽  
Type Iii ◽  
Analytic Expressions ◽  
Study Type ◽  
Theoretical Results

In this paper, we extend a methodology developed recently to study type-III intermittency considering different values of the noise intensity and the lower boundary of reinjection (LBR). We obtain accurate analytic expressions for the reinjection probability density (RPD). The proposed RPD has a piecewise definition depending on the nonlinear behavior, the LBR value, and the noise intensity. The new RPD is a sum of exponential functions with exponent α + 2, where α is the exponent of the noiseless RPD. The theoretical results are verified with the numerical simulations.

NGHIÊN CỨU SỰ KHUẾCH TÁN CỦA NGUYÊN TỬ XEN KẼ TRONG HỢP KIM XEN KẼ AuSi VỚI CẤU TRÚC LẬP PHƯƠNG TÂM DIỆN

2021 ◽  
Vol 66 (1) ◽  
pp. 30-41
Author(s):  
Hoc Nguyen Quang ◽  
Hien Nguyen Duc ◽  
Le Nguyen Ngoc ◽  
Linh Vu Thuy ◽  
Trang Pham Huyen ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Moment Method ◽  
Statistical Moment ◽  
Numerical Results ◽  
Arrhenius Law ◽  
Analytic Expressions ◽  
Theoretical Results ◽  
Fcc Structure ◽  
Statistical Moment Method

The paper derives analytic expressions of the diffusion coefficient depending on strain and pressure for the interstitial alloy AB with FCC structure by the statistical moment method based on previous studies for metals and semiconductors. Theoretical results are applied to alloy AuSi. Our numerical results satisfy the Arrhenius law

scholarly journals Synchronizability of Multilayer Star and Star-Ring Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Yang Deng ◽  
Zhen Jia ◽  
Feimei Yang
Keyword(s):  
Structural Parameters ◽  
Interlayer Coupling ◽  
Ring Networks ◽  
Stability Function ◽  
Eigenvalue Spectrum ◽  
Number Of Layers ◽  
Analytic Expressions ◽  
Coupling Strengths ◽  
The Relationship ◽  
Theoretical Results

Synchronization of multilayer complex networks is one of the important frontier issues in network science. In this paper, we strictly derived the analytic expressions of the eigenvalue spectrum of multilayer star and star-ring networks and analyzed the synchronizability of these two networks by using the master stability function (MSF) theory. In particular, we investigated the synchronizability of the networks under different interlayer coupling strength, and the relationship between the synchronizability and structural parameters of the networks (i.e., the number of nodes, intralayer and interlayer coupling strengths, and the number of layers) is discussed. Finally, numerical simulations demonstrated the validity of the theoretical results.

scholarly journals Sampling Errors in Ensemble Kalman Filtering. Part II: Application to a Barotropic Model

2009 ◽  
Vol 137 (5) ◽  
pp. 1640-1654 ◽  
Author(s):  
William Sacher ◽  
Peter Bartello
Keyword(s):  
Kalman Filter ◽  
Kalman Filtering ◽  
Ensemble Kalman Filter ◽  
Computational Cost ◽  
Sampling Errors ◽  
Analytic Expressions ◽  
Quasigeostrophic Model ◽  
Filter Divergence ◽  
Ensemble Kalman Filtering ◽  
Theoretical Results

Abstract In the current study, the authors are concerned with the comparison of the average performance of stochastic versions of the ensemble Kalman filter with and without covariance inflation, as well as the double ensemble Kalman filter. The theoretical results obtained in Part I of this study are confronted with idealized simulations performed with a perfect barotropic quasigeostrophic model. Results obtained are very consistent with the analytic expressions found in Part I. It is also shown that both the double ensemble Kalman filter and covariance inflation techniques can avoid filter divergence. Nevertheless, covariance inflation gives efficient results in terms of accuracy and reliability for a much lower computational cost than the double ensemble Kalman filter and for smaller ensemble sizes.

Kinetic theory and simulation of electron-strahl scattering in the solar wind

2020 ◽  
Author(s):  
Daniel Verscharen ◽  
Seong-Yeop Jeong ◽  
Benjamin Chandran ◽  
Chadi Salem ◽  
Marc Pulupa ◽  
...  
Keyword(s):  
Solar Wind ◽  
Numerical Solutions ◽  
Mathematical Framework ◽  
Physical Mechanisms ◽  
The Core ◽  
Hot Plasma ◽  
Analytic Expressions ◽  
Core Electrons ◽  
Electron Gyrofrequency ◽  
Theoretical Results

<p>We investigate the scattering of strahl electrons by microinstabilities as a mechanism for creating the electron halo in the solar wind. We develop a mathematical framework for the description of electron-driven microinstabilities and discuss the associated physical mechanisms. We find that an instability of the oblique fast-magnetosonic/whistler (FM/W) mode is the best candidate for a microinstability that scatters strahl electrons into the halo. We derive approximate analytic expressions for the FM/W instability threshold in two different β<sub>c </sub>regimes, where β<sub>c</sub> is the ratio of the core electrons' thermal pressure to the magnetic pressure, and confirm the accuracy of these thresholds through comparison with numerical solutions to the hot-plasma dispersion relation. We find that the strahl-driven oblique FM/W instability creates copious FM/W waves under low-β<sub>c</sub> conditions when U<sub>0s</sub>>3w<sub>c</sub>, where U<sub>0s</sub> is the strahl speed and w<sub>c </sub>is the thermal speed of the core electrons. These waves have a frequency of about half the local electron gyrofrequency. We also derive an analytic expression for the oblique FM/W instability for β<sub>c</sub>~1. The comparison of our theoretical results with data from the <em>Wind</em> spacecraft confirms the relevance of the oblique FM/W instability for the solar wind. In addition, we find a good agreement between our theoretical results and numerical solutions to the quasilinear diffusion equation. We make predictions for the electron strahl close to the Sun, which will be tested by measurements from <em>Parker Solar Probe</em> and <em>Solar Orbiter</em>.</p>

The restoration of blurred electron micrographs

1986 ◽  
Vol 44 ◽  
pp. 180-181
Author(s):  
Bridget Carragher ◽  
David A. Bluemke ◽  
Michael J. Potel ◽  
Robert Josephs
Keyword(s):  
Cross Section ◽  
Electron Micrographs ◽  
Relative Motion ◽  
Finite Thickness ◽  
Image Plane ◽  
Helical Axis ◽  
Thin Sections ◽  
Structural Details

We have investigated the feasibility of restoring blurred electron micrographs. Two related problems have been considered; the restoration of images blurred as a result of relative motion between the specimen and the image plane, and the restoration of images which are rotationally blurred about an axis. Micrographs taken while the specimen is drifting result in images which are blurred in the direction of motion. An example of rotational blurring arises in micrographs of thin sections of helical particles viewed in cross section. The twist of the particle within the finite thickness of the section causes the image to appear rotationally blurred about the helical axis. As a result, structural details, particularly at large distances from the helical axis, will be obscured.

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