scholarly journals Dynamic invariance in near field acoustic levitation

2021 ◽  
pp. 1-8
Author(s):  
Nicolas Elie ◽  
Antoinette Blouin ◽  
Noel Brunetiere
Keyword(s):  
Energy Efficiency ◽  
Moving Objects ◽  
Theoretical Study ◽  
Near Field ◽  
Acoustic Levitation ◽  
Plate Vibration ◽  
Unusual Behavior ◽  
Flat Disk ◽  
Input Signals ◽  
Air Film

Abstract It is possible to levitate a mass by vibrating a flat disk located under the mass. This near-field acoustic levitation is particularly useful for eliminating friction between moving objects. This paper presents an experimental and theoretical study of the dynamic behavior of a levitating mass for different magnitudes of oscillation of the flat disk. The magnitude of the vibration of the mass appears to be independent of the amplitude of the vibration of the disk over a range of two orders of magnitude. This unusual behavior is due to the simultaneous changes of the stiffness of the air film and the natural frequency of the system as the plate vibration is changed. As the plate oscillation is reduced, the distance to resonance decreases, allowing an increase of the ratio of the output to input signals in such a way that the output remains constant. This result can be useful for improving the energy efficiency of the levitation.

Acoustic radiation simulation and pre-stress effect on compact acoustic levitation platform

2019 ◽  
Vol 33 (07) ◽  
pp. 1950080 ◽  
Author(s):  
Bin Wei ◽  
Yongyong He ◽  
Wei Wang
Keyword(s):  
Pressure Distribution ◽  
Acoustic Radiation ◽  
Near Field ◽  
Parameters Optimization ◽  
Squeeze Film ◽  
Acoustic Levitation ◽  
Stress Effect ◽  
Biological Engineering ◽  
Loop Control ◽  
Close Loop Control

In order to satisfy the requirements of precise components with tidiness, low power and high stability in the field of biological engineering, medical equipment and semiconductors etc. a pre-stress acoustic transport prototype without horn was proposed in this paper. The mechanism of levitation and transport which is driven by orthogonal waves was revealed by the analysis of waveform and squeeze film characteristics in high-frequency exciting condition; also, the electric, solid and acoustic coupled finite element method (FEM) was established to investigate the effect of pre-stress and acoustic pressure distribution in the near field. The levitation and driving capacity of near field acoustic levitation (NFAL) transport platform without horns can be proved in this experiment and further to achieve the goal of parameters optimization. The theoretical and experimental results indicate that the pre-stress has a significant effect on resonant frequency and levitating stability, the pre-stress are determined by the DC voltage offset which is related to the system working point so that we cannot increase the offset and exciting voltage unlimitedly to improve the stability. At the same time, the calculated pressure distribution of acoustic radiation can generally reflect the regional bearing capacity in near and far field for levitation. These achievements can partly solve the problem of accuracy design of prototype and thickness of gas film, supporting for accuracy close loop control of levitating height.

scholarly journals Theoretical study of nanophotonic directional couplers comprising near-field-coupled metal nanoparticles

2011 ◽  
Vol 19 (8) ◽  
pp. 7885 ◽  
Author(s):  
Petter Holmström ◽  
Jun Yuan ◽  
Min Qiu ◽  
Lars Thylén ◽  
Alexander M. Bratkovsky
Keyword(s):  
Metal Nanoparticles ◽  
Theoretical Study ◽  
Near Field ◽  
Directional Couplers

scholarly journals Model of Window Able to Create Regenerated Interior Cold Air Film

2021 ◽  
Author(s):  
Mahmoud Majzoub
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Residential Buildings ◽  
Engineering Majors ◽  
Architectural Engineering ◽  
Building Energy Conservation ◽  
Strongly Connected ◽  
Building Life Cycle ◽  
Air Film ◽  
Building Engineering

Building Engineering or Architectural engineering, is a major of science that deals with engineering aspects in buildings, such as structure, construction, site management, mechanical, electric, lighting, acoustic, and energy efficiency. Building engineering is one of unique sciences that is strongly connected with all other types of engineering majors. In addition, it is connected to human basic life directly, and its application is able to noticed easily. However, this research will focus on the field of energy efficiency and opening construction in buildings. The reason why building energy conservation grab more researchers ‘attention is the fact of its relation with all other engineering aspects, and it is a building property that is very important along building life cycle. Currently humanity are living in world that energy market is biggest market in the world after weapons(Levy 2010). Nevertheless, energy in middle east is an important factor, especially when we know that country like Saudi Arabia, 75% of inside energy consumption goes to residential buildings(Of and Audits n.d.). And the reason why these buildings consume that much refers to high usage of energy in building applications, and leak of using eco-friendly building material that able to reduce energy consumption in buildings.

Theoretical study of an absorbing sample in infrared near-field spectromicroscopy

2004 ◽  
Vol 235 (4-6) ◽  
pp. 351-360 ◽  
Author(s):  
A. Dazzi ◽  
S. Goumri-Said ◽  
L. Salomon
Keyword(s):  
Theoretical Study ◽  
Near Field

scholarly journals Near-field acoustic levitation and applications to bearings: a critical review

2019 ◽  
Vol 1 (3) ◽  
pp. 032002 ◽  
Author(s):  
Minghui Shi ◽  
Kai Feng ◽  
Junhui Hu ◽  
Jiang Zhu ◽  
Hailong Cui
Keyword(s):  
Critical Review ◽  
Near Field ◽  
Acoustic Levitation
Sign in / Sign up

Export Citation Format

Share Document