Experimental verification of a short method for the determination of the acoustical insulation index of party walls

1989 ◽  
Vol 28 (2) ◽  
pp. 83-94
Author(s):  
Alessandro Cocchi ◽  
Massimo Garai
2021 ◽  
Vol 185 ◽  
pp. 1-13
Author(s):  
Di Zhao ◽  
Chong Sun ◽  
Zhanxia Zhu ◽  
Wenya Wan ◽  
Zixuan Zheng ◽  
...  

1968 ◽  
Vol 22 (2) ◽  
pp. 261-270 ◽  
Author(s):  
P. Rispens ◽  
J.R. Brunsting ◽  
W.G. Zijlstra ◽  
E.J. Van Kampen

Tribologia ◽  
2019 ◽  
Vol 287 (5) ◽  
pp. 13-17
Author(s):  
Bartosz BASTIAN ◽  
Rafał GAWARKIEWICZ

The literature describes acoustic levitation phenomena with the utilization of air squeeze film between the vibrating inducer and the lifted object. The objective of the study is to determine the shape of the inducer with vibration characteristics that would allow the levitation of an object of the assumed geometry. In this paper, the influence of the dimension ratio of the inducer on the frequency of the first mode of vibration was presented. CFD calculations for a selected dimension series were performed with the goal of the determination of lifting conditions. The data obtained from the analysis will be used to manufacture an inducer that will serve as an experimental verification for the fluid dynamics calculation.


Author(s):  
Erik Prada

Urgency of the research. The potential of controlling the position of levitating objects has great application in deposition and in various positioning systems. Magnetic levitation eliminates direct mechanical friction between moving parts. Target setting. The measurement shielding method used is one of the methods of determining the position of a levitating object. By combining positioning and regulating elements, we achieve a feedback control. The use of a given type of measurement has advantages in places where the use of other methods is not appropriate. Actual scientific researches and issues analysis. The problem of magnetic levitation is addressed by several research laboratories with a direct connection to practice. The problem that is currently solved within magnetic levitation is the regulation of the levitating object using various types of regulators. The research objective. Derivation of mathematical model of magnetic levitation and examination of nonlinear system followed by linearization by Taylor series. Experimental determination of characteristics and dependence between object position, voltage and current. The statement of basic materials. The position of the levitating object is determined by the shading of the optical sensor. The light source is a laser light. Conclusions. In this work we defined the mathematical model of the magnetic levitation system and subsequently derived the transfer function of the levitation system and the position sensor. From the experimental verification of the shadow method for the determination of the position of the levitating object and the consequent need for regulation, we found that the dependence of the position of the levitating object on current and voltage on the photodiode is linear in the active region.


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