Analysis on vibration energy concentration of the one-dimensional wedge-shaped acoustic black hole structure

2018 ◽  
Vol 29 (10) ◽  
pp. 2137-2148 ◽  
Author(s):  
Xi Li ◽  
Qian Ding
Keyword(s):  
Black Hole ◽  
Strain Energy ◽  
Energy Ratio ◽  
Energy Concentration ◽  
Vibration Energy ◽  
Maximum Height ◽  
The One ◽  
Hole Structure ◽  
Hole Effect ◽  
Strain Energy Ratio

The transverse vibration energy of a plate with a wedge-shaped profile can be trapped by acoustic black hole effect to its edge portion, in case the wedge thickness is diminished according to the power-law h( x) =  εxm with m ≥ 2.0. The acoustic black hole effect exhibits potential ability for passive vibration control and energy harvesting. In this article, the transfer matrix method is adopted to establish and solve the dynamical model of acoustic black hole structure. Energy ratio is defined as a ratio of the energy trapped within the edge portion to that of the whole wedge, to illustrate the energy concentration effect. Analyses show that both the strain energy ratio and kinetic energy ratio of the acoustic black hole structure achieve the minimum when the wedge is in resonances, although these two kinds of energy come to peaks at this case. However, in the case of small length of the edge portion, the strain energy ratio reaches the highest peaks at the second and higher resonances, rather than at the first one. Generally, the best effect of energy concentration occurs when m ranges from 2.5 to 3.0. Reducing the truncation thickness and increasing the maximum height can improve the energy trapping.

Surfing the Quantum World

2017 ◽  
Author(s):  
Frank S. Levin
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Musical Instrument ◽  
Popular Science ◽  
Quantum Spin ◽  
Exclusion Principle ◽  
Maximum Height ◽  
Core Concepts ◽  
The Many ◽  
The One

Surfing the Quantum World bridges the gap between in-depth textbooks and typical popular science books on quantum ideas and phenomena. Among its significant features is the description of a host of mind-bending phenomena, such as a quantum object being in two places at once or a certain minus sign being the most consequential in the universe. Much of its first part is historical, starting with the ancient Greeks and their concepts of light, and ending with the creation of quantum mechanics. The second part begins by applying quantum mechanics and its probability nature to a pedagogical system, the one-dimensional box, an analog of which is a musical-instrument string. This is followed by a gentle introduction to the fundamental principles of quantum theory, whose core concepts and symbolic representations are the foundation for most of the subsequent chapters. For instance, it is shown how quantum theory explains the properties of the hydrogen atom and, via quantum spin and Pauli’s Exclusion Principle, how it accounts for the structure of the periodic table. White dwarf and neutron stars are seen to be gigantic quantum objects, while the maximum height of mountains is shown to have a quantum basis. Among the many other topics considered are a variety of interference phenomena, those that display the wave properties of particles like electrons and photons, and even of large molecules. The book concludes with a wide-ranging discussion of interpretational and philosophic issues, introduced in Chapters 14 by entanglement and 15 by Schrödinger’s cat.

scholarly journals VIBRATION ENERGY DISSIPATION OF A COMPOSITE MATERIAL/KOMPOZICINĖS MEDŽIAGOS VTRPESIŲ ENERGIJOS DISIPACIJA

1998 ◽  
Vol 4 (4) ◽  
pp. 280-282
Author(s):  
Petras Baradokas
Keyword(s):  
Composite Material ◽  
Energy Dissipation ◽  
Strain Energy ◽  
Vibration Energy ◽  
Separate Component ◽  
Dissipation Coefficient ◽  
Energy Dissipation Coefficient

The paper discusses the problem of evaluating vibration energy dissipation of a composite material. It is suggested to express the dissipation cofficient in a line (2). The reduced component dissipation coefficients c i φi are the members of the line. The ratio of reduction c i , shows the proportion by which a separate component adds to the energy dissipation of the entire composition. By analysing the accumulated and dissipated strain energy of a composite material were obtained (6). On the basis of these expressions, formulas for calculating the dissipation coefficients of a three-layer bar and that with a galvanic covering were devised. The analysis made leads to the following conclusions: - the vibration energy dissipation coefficient of a composite material is equal to the sum of the reduced dissipation coefficients of the composition component materials; - the ratio of reduction c i depends on the value of the component accumulated energy; - for comparing separate components as to the energy dissipation, the product φ i E i should be used.

BLACK HOLE - DESTROYER

2021 ◽  
Author(s):  
Иштимер Шагалиевич Хурамшин
Keyword(s):  
Black Hole ◽  
The Other ◽  
Baryonic Matter ◽  
Evolution Of The Universe ◽  
The Galaxy ◽  
The One ◽  
The Universe

В статье обсуждается вопрос о двух противоположных функциях черной дыры. С одной стороны она является творцом для галактики, а с другой - разрушителем барионной материи. Предполагается, что эти функции заложены самой эволюцией Вселенной. Деструкция материи до фотонов в ЧД считается наиболее вероятным событием. The question of two opposite functions of a black hole is discussed. On the one hand, it is the creator for the galaxy, and on the other-the destroyer of baryonic matter. It is assumed that these functions were laid down by the evolution of the Universe itself. The destruction of matter to photons in BH is considered the most likely event.

Interpretation of the Acoustic Black Hole effect based on the concept of critical coupling

2020 ◽  
Vol 471 ◽  
pp. 115199 ◽  
Author(s):  
J. Leng ◽  
V. Romero-García ◽  
A. Pelat ◽  
R. Picó ◽  
J.-P. Groby ◽  
...  
Keyword(s):  
Black Hole ◽  
Critical Coupling ◽  
Hole Effect
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