scholarly journals The Experimental Registration of the Evanescent Acoustic Wave in YX LiNbO3 Plate

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2238
Author(s):  
Andrey Smirnov ◽  
Boris Zaitsev ◽  
Andrey Teplykh ◽  
Ilya Nedospasov ◽  
Egor Golovanov ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Three Dimensional ◽  
Evanescent Waves ◽  
Electrical Boundary Conditions ◽  
3D Finite Element Method ◽  
First Time ◽  
Theoretical Results ◽  
Good Agreement ◽  
Piezoelectric Plates

Evanescent acoustic waves are characterized by purely imaginary or complex wavenumbers. Earlier, in 2019 by using a three dimensional (3D) finite element method (FEM) the possibility of the excitation and registration of such waves in the piezoelectric plates was theoretically shown. In this paper the set of the acoustically isolated interdigital transducers (IDTs) with the different spatial periods for excitation and registration of the evanescent acoustic wave in Y-cut X-propagation direction of lithium niobate (LiNbO3) plate was specifically calculated and produced. As a result, the possibility to excite and register the evanescent acoustic wave in the piezoelectric plates was experimentally proved for the first time. The evanescent nature of the registered wave has been established. The theoretical results turned out to be in a good agreement with the experimental ones. The influence of an infinitely thin layer with arbitrary conductivity placed on a plate surface was also investigated. It has been shown that the frequency region of an evanescent acoustic wave existence is very sensitive to the changes of the electrical boundary conditions. The results obtained may be used for the development of the method of the analysis of thin films electric properties based on the study of evanescent waves.

Waves of Acoustically Induced Transparency in Bubbly Liquids: Theoretical Prediction and Experimental Validation

2013 ◽  
Author(s):  
Nail A. Gumerov ◽  
Iskander S. Akhatov ◽  
Claus-Dieter Ohl ◽  
Sergei P. Sametov ◽  
Maxim V. Khasimulin ◽  
...  
Keyword(s):  
Acoustic Field ◽  
Acoustic Waves ◽  
Three Dimensional ◽  
Self Organization ◽  
Nonlinear Phenomenon ◽  
Three Dimensional Model ◽  
Bubbly Liquids ◽  
Strongly Nonlinear ◽  
Induced Transparency ◽  
Good Agreement

Self-organization of bubbles in acoustic fields, or self-action of the acoustic waves in bubbly liquids is a strongly nonlinear phenomenon due to two-way interaction of the bubbles and the acoustic field. Theoretical model and preliminary computations predict that waves of self-induced acoustic transparency may exist. Such effect is confirmed in the experiments presented in this paper. Formation of a wave of void fraction which rapidly propagates through the bubbly medium leaving a region almost free of bubbles behind its front is observed in the experiments. Measurements of the dynamics of such a wave at different acoustic frequencies and amplitudes are carried out. A three dimensional model of self-organization of a polydisperse bubble continuum in acoustic field is developed and the results of simulations are compared with experiments. A good agreement of the theory and experiment is found.

A New Method to “Lock-in” Elastic Effects for Experimental Stress Analysis

1958 ◽  
Vol 25 (2) ◽  
pp. 189-195
Author(s):  
J. W. Dally ◽  
A. J. Durelli ◽  
W. F. Riley
Keyword(s):  
Three Dimensional ◽  
New Method ◽  
Experimental Stress Analysis ◽  
Gravitational Loading ◽  
Distorted Grid ◽  
Gravitational Stress ◽  
Lock In ◽  
Modified Epoxy ◽  
Theoretical Results ◽  
Good Agreement

Abstract A new method is described for “locking-in” an optical interference pattern and a mechanical distortion. The transparent model is cast from a modified epoxy resin with an embedded rubber-thread grid. The model is permitted partially to cure before it is loaded, then held under load while the plastic continues to cure. Upon removal of the load an isochromatic fringe pattern remains which is proportional to the elastic distribution of the maximum shearing stress. In addition, the permanently distorted grid has deformations which are proportional to the elastic distribution of strains. The method is applied to a disk under diametrical compression and a disk under gravitational loading. A comparison of experimental and theoretical results for these two cases shows, in general, good agreement. Most of the discrepancies between experimental and theoretical results are due to the large deformations in the neighborhood of the points of load application. An application of the method to the solution of a three-dimensional problem, namely, the gravitational stress distribution in a buttress-type dam, is discussed briefly.

Ratchet mechanism of drops climbing a vibrated oblique plate

2017 ◽  
Vol 835 ◽  
Author(s):  
Hang Ding ◽  
Xi Zhu ◽  
Peng Gao ◽  
Xi-Yun Lu
Keyword(s):  
Contact Angle ◽  
Theoretical Analysis ◽  
Numerical Simulations ◽  
Contact Angle Hysteresis ◽  
Three Dimensional ◽  
Direct Numerical Simulations ◽  
Ratchet Mechanism ◽  
Wetted Area ◽  
First Time ◽  
Good Agreement

In this paper, we investigate the ratchet mechanism of drops climbing a vibrated oblique plate based on three-dimensional direct numerical simulations, which for the first time reproduce the existing experiment (Brunet et al., Phys. Rev. Lett., vol. 99, 2007, 144501). With the help of numerical simulations, we identify an interesting and important wetting behaviour of the climbing drop; that is, the breaking of symmetry due to the inclination of the plate with respect to the acceleration leads to a hysteresis of the wetted area in one period of harmonic vibration. In particular, the average wetted area in the downhill stage is larger than that in the uphill stage, which is found to be responsible for the uphill net motion of the drop. A new hydrodynamic model is proposed to interpret the ratchet mechanism, taking account of the effects of the acceleration and contact angle hysteresis. The predictions of the theoretical analysis are in good agreement with the numerical results.

Transient Radiation Element Method for Three-Dimensional Scattering, Absorbing, and Emitting Media

2001 ◽  
Author(s):  
Zhixiong Guo ◽  
Sunil Kumar ◽  
Shigenao Maruyama
Keyword(s):  
Radiative Transfer ◽  
Transient Analysis ◽  
Radiative Heat ◽  
Three Dimensional ◽  
The Media ◽  
Emitting Media ◽  
Inhomogeneous Properties ◽  
First Time ◽  
Good Agreement ◽  
Element Method

Abstract In this study transient radiative heat transfer is investigated in scattering, absorbing, and emitting media. The radiation element method is formulated for the first time to solve the transient radiative transfer equation in 3-D geometries. The sensitivity and accuracy of the method are examined. A good agreement of temporal transmittance predicted by the present method and Monte Carlo method is found. The characteristics of transient analysis are investigated via various problems of radiative transfer in inhomogeneous cubes. It is found that the transmitted signals are strongly affected by the inhomogeneous properties of the media through which the radiation has passed. In the position where the radiation travels a larger optical thickness, the broadening of the transmitted pulse width is more obvious and the magnitude of the transmittance is smaller.

Theoretical calculation of the low-lying quartet states of the CrF molecule

2011 ◽  
Vol 89 (10) ◽  
pp. 1304-1311 ◽  
Author(s):  
A. Hamdan ◽  
M. Korek
Keyword(s):  
Dipole Moment ◽  
Potential Energy ◽  
Ground State ◽  
Electronic States ◽  
Rotational Constant ◽  
Electronic Energy ◽  
Harmonic Frequency ◽  
First Time ◽  
Theoretical Results ◽  
Good Agreement

The potential energy curves have been investigated for the 11 lowest quartet electronic states in the 2s+1Λ± representation below 28 000 cm–1 of the molecule CrF via CASSCF and MRCI (single and double excitations with Davidson correction) calculations. Eight electronic states have been studied theoretically for the first time. The harmonic frequency ωe, the internuclear distance re, the rotational constant Be, the electronic energy with respect to the ground state Te, and the permanent dipole moment μ have been calculated. By using the canonical functions approach, the eigenvalues Ev, the rotational constant Bv, and the abscissas of the turning points rmin and rmax have been calculated for electronic states up to the vibrational level v = 38. The comparison of these values to the theoretical results available in the literature shows a very good agreement.

On the response of a poro-elastic bed to water waves

1978 ◽  
Vol 87 (1) ◽  
pp. 193-206 ◽  
Author(s):  
Tokuo Yamamoto ◽  
H. L. Koning ◽  
Hans Sellmeijer ◽  
Ep Van Hijum
Keyword(s):  
Porous Medium ◽  
Pore Water ◽  
Water Waves ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Fine Sand ◽  
Present Solution ◽  
Theoretical Results ◽  
Good Agreement

The problem of the response of a porous elastic bed to water waves is treated analytically on the basis of the three-dimensional consolidation theory of Biot (1941). Exact solutions for the pore-water pressure and the displacements of the porous medium are obtained in closed form for the case of waves propagating over the poro-elastic bed. The theoretical results indicate that the bed response to waves is strongly dependent on the permeabilitykand the stiffness ratioG/K’, whereGis the shear modulus of the porous medium andK’is the apparent bulk modulus of elasticity of the pore fluid. The earlier solutions for pore-water pressure by various authors are given as the limiting cases of the present solution. For the limitsG/K′→ 0 ork→ ∞, the present solution for pressure approaches the solution of the Laplace equation by Putnam (1949). For the limitG/K′→ ∞, the present solution approaches the solution of the heat conduction equation by Nakamuraet al.(1973) and Moshagen & Tørum (1975).The theoretical results are compared with wave tank experimental data on pore-water pressure in coarse and fine sand beds which contain small amounts of air. Good agreement between theory and experiment is obtained.

Torque and Cavitation Characteristics of Butterfly Valves

1961 ◽  
Vol 28 (4) ◽  
pp. 511-518 ◽  
Author(s):  
Turgut Sarpkaya
Keyword(s):  
Approximate Solution ◽  
Three Dimensional ◽  
Relaxation Technique ◽  
Dimensional Case ◽  
Practical Case ◽  
Two Dimensional ◽  
Actual Flow ◽  
Theoretical Results ◽  
Good Agreement

The present study deals with torque and cavitation characteristics of idealized two-dimensional and axially symmetrical butterfly valves. Theoretical results obtained for the two-dimensional case are compared with the ones obtained experimentally and by a relaxation technique. Based on the results of the two-dimensional case, an approximate solution is presented for the more general and practical case of three-dimensional butterfly valves. The results are in good agreement with the actual flow tests.

Understanding how cAMP-dependent protein kinase can catalyze phosphoryl transfer in the presence of Ca2+and Sr2+: a QM/MM study

2017 ◽  
Vol 19 (16) ◽  
pp. 10377-10394 ◽  
Author(s):  
Ayax Pérez-Gallegos ◽  
Mireia Garcia-Viloca ◽  
Àngels González-Lafont ◽  
José M. Lluch
Keyword(s):  
Alkaline Earth ◽  
Transfer Reaction ◽  
Earth Metal ◽  
Phosphoryl Transfer ◽  
Dependent Protein Kinase ◽  
Alkaline Earth Metal Ions ◽  
Dependent Protein ◽  
First Time ◽  
Theoretical Results ◽  
Good Agreement

Theoretical results demonstrate for the first time at the molecular level that the overall PKAc-catalyzed phosphoryl-transfer reaction is plausible with Ca2+and Sr2+, alkaline earth metal ions other than Mg2+, which is in good agreement with experiments.

APPLICATION OF ELASTIC MATERIALS IN PROTECTION FROM STRONG IMPACTS

2004 ◽  
Vol 18 (14) ◽  
pp. 1977-1990
Author(s):  
MASKOVIC D. LJILJANA ◽  
MOHORA EMILIJAN ◽  
TOSIC S. BRATISLAV ◽  
VUJOVIC R. RATKO
Keyword(s):  
Elastic Material ◽  
Short Pulse ◽  
Three Dimensional ◽  
Polymer Materials ◽  
Elastic Materials ◽  
One Dimensional ◽  
Spherical Surfaces ◽  
The Impact ◽  
Theoretical Results ◽  
Good Agreement

The analysis of the behavior of elastic material subject to strong short pulse impact has shown that only one-dimensional structures support the impact without destruction. Compact two- and three-dimensional structures are destroyed during the impact along circular lines and spherical surfaces. For that reason, web-like shields are proposed for the protection of man and equipment. Polymer materials are most suitable for the production of web-like shields since they are made of fibers and highly stress resistant. Theoretical results are experimentally tested and the good agreement with theory was found.

scholarly journals Polarization-insensitive 3D conformal-skin metasurface cloak

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
He-Xiu Xu ◽  
Guangwei Hu ◽  
Yanzhao Wang ◽  
Chaohui Wang ◽  
Mingzhao Wang ◽  
...  
Keyword(s):  
3D Printing ◽  
Incident Light ◽  
Three Dimensional ◽  
Free Form ◽  
Polarization Insensitive ◽  
Wavelength Scale ◽  
First Time ◽  
Printing Techniques ◽  
Flat Ground ◽  
Good Agreement

AbstractElectromagnetic metasurface cloaks provide an alternative paradigm toward rendering arbitrarily shaped scatterers invisible. Most transformation-optics (TO) cloaks intrinsically need wavelength-scale volume/thickness, such that the incoming waves could have enough long paths to interact with structured meta-atoms in the cloak region and consequently restore the wavefront. Other challenges of TO cloaks include the polarization-dependent operation to avoid singular parameters of composite cloaking materials and limitations of canonical geometries, e.g., circular, elliptical, trapezoidal, and triangular shapes. Here, we report for the first time a conformal-skin metasurface carpet cloak, enabling to work under arbitrary states of polarization (SOP) at Poincaré sphere for the incident light and arbitrary conformal platform of the object to be cloaked. By exploiting the foundry three-dimensional (3D) printing techniques to fabricate judiciously designed meta-atoms on the external surface of a conformal object, the spatial distributions of intensity and polarization of its scattered lights can be reconstructed exactly the same as if the scattering wavefront were deflected from a flat ground at any SOP, concealing targets under polarization-scanning detections. Two conformal-skin carpet cloaks working for partial- and full-azimuth plane operation are respectively fabricated on trapezoid and pyramid platforms via 3D printing. Experimental results are in good agreement with numerical simulations and both demonstrate the polarization-insensitive cloaking within a desirable bandwidth. Our approach paves a deterministic and robust step forward to the realization of interfacial, free-form, and full-polarization cloaking for a realistic arbitrary-shape target in real-world applications.

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