APPARATUS FOR ABSORBING ACOUSTICAL ENERGY AND USE THEREOF

2013 ◽  
Vol 133 (2) ◽  
pp. 1195
Author(s):  
Siwei Zou
Keyword(s):  
Acoustical Energy

103. Use of Acoustical Energy for Particle Resuspension

2000 ◽  
Author(s):  
S. Azadi ◽  
A. Afshari ◽  
D. Frazer
Keyword(s):  
Particle Resuspension ◽  
Acoustical Energy

Analysis of Acoustical Properties of a Gear Mechanism

1997 ◽  
Author(s):  
Evgueni I. Podzharov
Keyword(s):  
Noise Level ◽  
Wide Frequency Range ◽  
High Mode ◽  
Frequency Range ◽  
Dynamic Calculation ◽  
Acoustical Properties ◽  
Gear Mechanism ◽  
Surrounding Space ◽  
Gear Meshes ◽  
Acoustical Energy

Abstract For an analysis of the acoustical properties of a multistage gear mechanism, a technique was used that combines a dynamic calculation of the mechanism as multimass multicoupling system and the SEA method for the calculation of acoustical energy. The dynamic calculation was used to determine the energy introduced into the mechanism’s gear meshes and the energy transmitted to the housing. The SEA method was used for the calculation of propagation of acoustical energy in the structure and its radiation in the surrounding space. Such a combination permits us to utilize the advantage of dynamic calculation accurately describing the mechanism’s performance and the SEA method for describing an acoustical model having the elements of high mode density in a wide frequency range. Some useful results were obtained which permit us to reduce noise level of the mechanism.

Noise Reduction Using Finite-Length Flexible Segments

1999 ◽  
Vol 122 (2) ◽  
pp. 94-108 ◽  
Author(s):  
Brian Chapnik ◽  
I. G. Currie
Keyword(s):  
Mathematical Model ◽  
Finite Length ◽  
Experimental Work ◽  
Acoustic Noise ◽  
Characteristic Impedance ◽  
Fluid Loading ◽  
Piping Systems ◽  
And Performance ◽  
Insertion Losses ◽  
Acoustical Energy

In this work, the reduction of acoustic noise in piping systems through the installation of finite flexible segments is explored. A mathematical model describing the relevant parameters is developed. To verify the model, experimental work is undertaken using rubber hoses as flexible segments and air as the contained fluid. The effect of the segment on propagating acoustical energy is studied in terms of its insertion loss. Both theoretical and experimental results indicate that, for light fluid loading, the flexibility of the segment is only important when significant axial shell resonances exist, or when one or both acoustical termination impedances at the ends of the segment are much larger or smaller than the characteristic impedance of the medium. Further, the model indicates that for heavier fluid loading (i.e., when the compressibility of the flexible section is significant in relation to the bulk compliance of the fluid), in addition to higher associated insertion losses, the finite length resonances become more pronounced, and performance is less sensitive to small variations in the termination impedances. [S0739-3717(00)00402-5]

Transient growth of acoustical energy associated with mitigating thermoacoustic oscillations

2016 ◽  
Vol 169 ◽  
pp. 481-490 ◽  
Author(s):  
Xinyan Li ◽  
Dan Zhao ◽  
Xinglin Yang ◽  
Huabing Wen ◽  
Xiao Jin ◽  
...  
Keyword(s):  
Transient Growth ◽  
Thermoacoustic Oscillations ◽  
Acoustical Energy

Analysis-By-Synthesis of Timbre, Timing, and Dynamics in Expressive Clarinet Performance

2011 ◽  
Vol 28 (3) ◽  
pp. 265-278 ◽  
Author(s):  
Mathieu Barthet ◽  
Philippe Depalle ◽  
Richard Kronland-Martinet ◽  
Søølvi Ystad
Keyword(s):  
Paired Comparison ◽  
Mean Square ◽  
Acoustical Parameters ◽  
Comparison Task ◽  
Spectral Centroid ◽  
Musical Preference ◽  
Clarinet Performance ◽  
Analysis By Synthesis ◽  
Synthesis Approach ◽  
Acoustical Energy

In a Previous Study, Mechanical and Expressive clarinet performances of Bach's Suite No. II and Mozart's Quintet for Clarinet and Strings were analyzed to determine whether some acoustical correlates of timbre (e.g., spectral centroid), timing (intertone onset interval), and dynamics (root mean square envelope) showed significant differences depending on the expressive intention of the performer. In the present companion study, we investigate the effects of these acoustical parameters on listeners' preferences. An analysis-by-synthesis approach was used to transform previously recorded clarinet performances by reducing the expressive deviations from the spectral centroid, the intertone onset interval and the acoustical energy. Twenty skilled musicians were asked to select which version they preferred in a paired comparison task. The results of statistical analyses showed that the removal of the spectral centroid variations resulted in the greatest loss of musical preference.

Aeroacoustical Coupling and Its Structural Effects on a PWR Steam Line: Part 2 — Vibroacoustical Analysis of Pipe Shell Deformations

2002 ◽  
Author(s):  
Se´bastien Caillaud ◽  
Christophe Lambert ◽  
Jean-Paul Devos ◽  
Philippe Lafon
Keyword(s):  
Energy Transfer ◽  
Finite Elements ◽  
Modal Analysis ◽  
Steam Line ◽  
Accurate Analysis ◽  
Analysis Of Dispersion ◽  
Fully Coupled ◽  
Finite Elements Model ◽  
Acoustical Energy ◽  
The Way

A pure tone phenomenon has been observed at 460 Hz in a PWR steam line. The acoustical energy has been identified to be generated in an open gate valve. The objective here is to understand the way of energy transfer from the fluid to the main pipe using two fully coupled methods. The first method consists in a modal analysis of the line using a fluid-structure finite elements model. The second one is based on the analysis of dispersion diagrams derived from the local equations of cylindrical shells filled with fluid. The way of energy transfer in transverse acoustical waves induced combined flexion-ovalisation deformations of the pipe is highlighted using both methods. The dispersion diagrams allow a fast and accurate analysis. The modal analysis using a finite elements model may complete the first one with quantitative data.

Development of an acoustical energy harvester

2005 ◽  
Vol 118 (3) ◽  
pp. 1945-1945
Author(s):  
Stephen B. Horowitz ◽  
Toshikazu Nishida ◽  
Louis N. Cattafesta ◽  
Mark Sheplak
Keyword(s):  
Energy Harvester ◽  
Acoustical Energy

Use of Echocardiography in Evaluation of General Pediatric Diseases

1981 ◽  
Vol 3 (5) ◽  
pp. 137-146
Author(s):  
Roberta G. Williams ◽  
Fredrick Z. Bierman
Keyword(s):  
Time Course ◽  
Cardiac Involvement ◽  
Soft Tissues ◽  
Spatial Information ◽  
Medical Personnel ◽  
The Body ◽  
Rapid Expansion ◽  
Pediatric Diseases ◽  
Serial Evaluation ◽  
Acoustical Energy

A variety of general pediatric diseases cause secondary cardiovascular abnormalities. Echocardiography and other noninvasive techniques have provided a better understanding of the incidence, time course, and degree of cardiac involvement in these disorders. Echocardiography yields anatomic and physiologic information with little patient discomfort and a relatively small investment in medical personnel and equipment and therefore offers a practical means for both population screening and serial evaluation of individual patients. When an ultrasound beam, produced by the rapid expansion and contraction of a rare earth crystal, is directed through the soft tissues of the body, some of the acoustical energy is absorbed and a portion is reflected back to the transducer. The depth and intensity of the returning signal can be displayed on an oscilloscope (A mode), or the signal can be swept across an oscilloscope or strip chart to record both depth and time (M-mode) as seen in Figs 1 and 2. Cardiac structures are identified by their characteristic motion and distance from the transducer. The transducer can be rotated or scanned from one structure to another in order to gain spatial information.

Sign in / Sign up

Export Citation Format

Share Document