Measurement of acoustic impedance of perforated plates in the presence of mean through flow

1982 ◽  
Vol 71 (S1) ◽  
pp. S78-S78
Author(s):  
Joseph W. Sullivan ◽  
Allan G. Doige
Keyword(s):  
Acoustic Impedance ◽  
Perforated Plates ◽  
Through Flow

A New Type of Muffler Based on Microperforated Tubes

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
S. Allam ◽  
M. Åbom
Keyword(s):  
Acoustic Impedance ◽  
Noise Control ◽  
Wave Impedance ◽  
Sound Waves ◽  
Submillimeter Range ◽  
Perforated Plates ◽  
Characteristic Wave ◽  
Standard Temperature ◽  
New Type ◽  
Temperature And Pressure

Microperforated plate (MPP) absorbers are perforated plates with holes typically in the submillimeter range and perforation ratios around 1%. The values are typical for applications in air at standard temperature and pressure (STP). The underlying acoustic principle is simple: It is to create a surface with a built in damping, which effectively absorbs sound waves. To achieve this, the specific acoustic impedance of a MPP absorber is normally tuned to be of the order of the characteristic wave impedance in the medium (∼400 Pa s/m in air at STP). The traditional application for MPP absorbers has been building acoustics often combined with a so called panel absorber to create an absorption peak at a selected frequency. However, MPP absorbers made of metal could also be used for noise control close to or at the source for noise control in ducts. In this paper, the possibility to build dissipative silencers, e.g., for use in automotive exhaust or ventilation systems, is investigated.

EFFECT OF GRAZING–BIAS FLOW INTERACTION ON ACOUSTIC IMPEDANCE OF PERFORATED PLATES

2002 ◽  
Vol 254 (3) ◽  
pp. 557-573 ◽  
Author(s):  
X. SUN ◽  
X. JING ◽  
H. ZHANG ◽  
Y. SHI
Keyword(s):  
Acoustic Impedance ◽  
Perforated Plates ◽  
Flow Interaction ◽  
Bias Flow

A New Method for Measuring Acoustic Impedance of Perforated Plates with Grazing Flow

2018 ◽  
Vol 2018.56 (0) ◽  
pp. 703
Author(s):  
Daisuke SHIRAGA ◽  
Shunsuke NAKAMURA ◽  
Shotaro YAMAZAKI ◽  
Shinji AKAMATSU ◽  
Yuki MITSUI ◽  
...  
Keyword(s):  
Acoustic Impedance ◽  
New Method ◽  
Perforated Plates ◽  
Grazing Flow

Research on the Absorption Characteristic of Three-Layer Microperforate Plate of the Automotive Body

2011 ◽  
Vol 201-203 ◽  
pp. 2160-2166
Author(s):  
Cong Yun Zhu
Keyword(s):  
Absorption Coefficient ◽  
Equivalent Circuit ◽  
Acoustic Impedance ◽  
Perforated Plate ◽  
Absorption Characteristic ◽  
Perforated Plates ◽  
Automotive Body ◽  
Different Thickness

Three-layer micro perforated plate of the automotive body is researched. Acoustic impedance of the three-layer microperforated plate of the automotive body is attained according to the equivalent circuit, thus absorption coefficient is attained. Different microperforated plate with different porosity, different diameter, different thickness, different depth of cavity of the automotive body is analyzed and some conclusion is drawn to applied some theory to design these types of the micro perforated plates of the automotive body.

Acoustic impedance of perforated plates in the presence of bias flow

2019 ◽  
Vol 446 ◽  
pp. 159-175 ◽  
Author(s):  
Zhixiang Chen ◽  
Zhenlin Ji ◽  
Hongpu Huang
Keyword(s):  
Acoustic Impedance ◽  
Perforated Plates ◽  
Bias Flow

Acoustic-Reflex Dynamics for Pulsed Signals

1978 ◽  
Vol 21 (2) ◽  
pp. 295-308
Author(s):  
Terry L. Wiley ◽  
Raymond S. Karlovich
Keyword(s):  
Duty Cycle ◽  
Acoustic Impedance ◽  
Normal Hearing ◽  
Broadband Noise ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Acoustic Reflex ◽  
Stapedius Muscle ◽  
Duty Cycles

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

THE DYNACTOME: INVESTIGATING DYNAMIC KINASE NETWORKS IN CELLULAR DECISION-MAKING

2008 ◽  
Vol 31 (4) ◽  
pp. 22
Author(s):  
Jonathan So ◽  
Kelly Elder ◽  
Anna Dai ◽  
Claus Jorgensen ◽  
Rune Linding ◽  
...  
Keyword(s):  
Spectrometric Analysis ◽  
Phosphorylation Sites ◽  
Complex Samples ◽  
Downstream Signaling ◽  
Through Flow ◽  
Colorectal Cancer Cells ◽  
Induced Apoptosis ◽  
Cell Phenotypes ◽  
Kinase Phosphorylation ◽  
Kinase Expression

Networks of kinases play a role in the transmission and integration of signals from the membrane to the nucleus. We aim to elucidate kinase phosphorylation and interaction partners in these networks through the immuno-precipitation and mass spectrometric analysis of a representative set of 100 Flag-tagged kinases stably expressed in human colorectal cancer cells. The goal is to generate a comprehensive set of interactions and dynamic phosphorylation sites which correlate with cell phenotypes such as apoptosis and proliferation. The techniques of mass-spectrometry have allowed for the identification of proteins and their phosphorylation sites in complex samples. Various labeling methods such as iTRAQ has enabled the relative quantification of these sites as afunction of time (White et al. PNAS, 2007). However, kinases usually work in the context of particular signaling stimuli. We aim to characterize the role of these over-expressed kinases in the context of Trail-induced apoptosis. This isparticularly relevant to tumorigenesis in that many cancers are resistant to apoptosis and recombinant Trail therapies are currently undergoing clinical trials. We present assays to correlate the proliferative ability and sensitivity to apoptosis of various stable cell lines with kinase expression levels through flow cytometry. We also present efforts to trace downstream signaling through the monitoring of MAP kinase phosphorylation using a high-throughput bead array.

Sign in / Sign up

Export Citation Format

Share Document