Comparison of impulse peak insertion loss measured with gunshot and shock tube noise sources

2014 ◽  
Vol 136 (4) ◽  
pp. 2165-2165
Author(s):  
William J. Murphy ◽  
Elliott H. Berger ◽  
William A. Ahroon
Keyword(s):  
Shock Tube ◽  
Insertion Loss ◽  
Noise Sources

Quantifying the insertion loss of hearing protection using a compressed gas shock tube

2018 ◽  
Vol 143 (3) ◽  
pp. 1934-1934
Author(s):  
Theodore F. Argo ◽  
Nate Greene ◽  
James Easter ◽  
Daniel J. Tollin ◽  
Timothy J. Walilko
Keyword(s):  
Shock Tube ◽  
Insertion Loss ◽  
Hearing Protection ◽  
Compressed Gas ◽  
Loss Of Hearing

Assessing a parallel baffle splitter, an experimental and numerical study on insertion loss and pressure drop

2021 ◽  
Vol 263 (6) ◽  
pp. 194-205
Author(s):  
Juan Pablo Escudero ◽  
Hctor Fuentes
Keyword(s):  
Pressure Drop ◽  
Insertion Loss ◽  
Numerical Study ◽  
Hvac Systems ◽  
Mechanical Equipment ◽  
Noise Sources ◽  
Acoustic Comfort ◽  
Design Velocity ◽  
Method Analysis ◽  
Experimental Rig

HVAC systems are composed of different noise sources and paths. The non-attenuated propagation of noise through the system has detrimental effects on acoustic comfort of people inside the premises. In order to mitigate the propagated noise, classic parallel baffe splitters are used to reduce the transmitted noise through acoustic coatings. Different methods have been developed to predict the insertion loss of those elements, however, if the input data is not well known these models can lead to deviated results. Additionally, the use of splitters in HVAC systems produces pressure drop which can damage the installed mechanical equipment if that is not well predicted. Currently, the models that estimate pressure drop relate dimensional features and design velocity. However, these models can give overestimated results. In this work an experimental rig was implemented to assess a splitter installed inside of a test duct. Measurements were performed to estimate insertion loss and pressure drop coeffcient, following the guidelines exposed on the ISO 7235 standard. The results were compared with analytical methods. Finally, a numerical method analysis of the test rig was performed, showing the correlation between these results and the experimental data.

Insertion loss (IL) of finite sound barriers of different contours - An introduction to geometrical solutions in 3-D space

2021 ◽  
Vol 263 (6) ◽  
pp. 164-174
Author(s):  
Giora Rosenhouse
Keyword(s):  
Insertion Loss ◽  
Vector Analysis ◽  
Control Points ◽  
Noise Sources ◽  
3D Space ◽  
Sound Barriers ◽  
Environmental Acoustics ◽  
And Control ◽  
Rectangular Barrier

The design of finite sound barriers noise sources and control points requires calculations beyond those that are used when the Maekawa formula is applied, since the problem involves polygon sd barriers located in various possible orientations in 3D space. We present here some means that are linked to basic mathematical geometrical tools. Those means are relatively simple, as compared to the physical formulation of the relevant diffraction solutions for sound barriers (e.g. Rosenhouse, 2019, 2020). Such calculations can apply algebraic, trigonometric or vector analysis and their combinations to define the geometries of barrier IL. This approach includes the location of the sources and control points, which are essential as data for finding IL and other issues of environmental acoustics. We will show solutions including results of IL for a common rectangular barrier, as compared to IL of a barrier with a sloped top and side, among other possibilities.

scholarly journals Measurement of impulse peak insertion loss from two acoustic test fixtures and four hearing protector conditions with an acoustic shock tube

2015 ◽  
Vol 17 (78) ◽  
pp. 364 ◽  
Author(s):  
WilliamJ Murphy ◽  
CameronJ Fackler ◽  
ElliottH Berger ◽  
PeterB Shaw ◽  
Mike Stergar
Keyword(s):  
Shock Tube ◽  
Insertion Loss ◽  
Hearing Protector

Assessing a parallel baffle splitter, an experimental and numerical study on insertion loss and pressure drop

2021 ◽  
Vol 263 (4) ◽  
pp. 2578-2589
Author(s):  
Juan Escudero ◽  
Héctor Fuentes
Keyword(s):  
Pressure Drop ◽  
Insertion Loss ◽  
Numerical Study ◽  
Hvac Systems ◽  
Test Rig ◽  
Noise Sources ◽  
Acoustic Comfort ◽  
Design Velocity ◽  
Method Analysis ◽  
Experimental Rig

HVAC systems are composed of different noise sources and paths. The non-attenuated propagation of noise through the system has detrimental effects on acoustic comfort of people inside the premises. To mitigate the propagated noise, parallel baffle splitters are used which reduce the transmitted noise through acoustic coatings. Different methods have been developed to predict the insertion loss of those elements, however, if the input data is not well known these models can lead to deviated results. On the other hand, the use of splitter in HVAC systems produces pressure drop which can damage the equipment used if that is not well predicted. Different models are available in the literature, which relates dimensional features and design velocity to estimate the pressure drop coefficient. However, models can give overestimated results. In this work an experimental rig was implemented to assess a splitter installed inside of a test duct. Measurements were performed to estimate insertion loss and pressure drop coefficient, following the guidelines exposed on the ISO 7235 standard. The results were compared with analytic methods. Finally, a numerical method analysis of the test rig was performed, showing the correlation between these results and the experimental data.

Using a shock tube to predict the response of polymeric foam to a blast loading

2006 ◽  
Vol 134 ◽  
pp. 783-787 ◽  
Author(s):  
S. Ouellet ◽  
D. Frost ◽  
A. Bouamoul
Keyword(s):  
Shock Tube ◽  
Blast Loading ◽  
Polymeric Foam

Pyrolysis of methane in a single pulse shock tube

1972 ◽  
Vol 22 (3) ◽  
pp. 303-317 ◽  
Author(s):  
D. H. Napier ◽  
N. Subrahmanyam
Keyword(s):  
Shock Tube ◽  
Single Pulse

Method for Evaluating Insertion Loss of EMI Filter Connected to Semiconductor Power Converters

2012 ◽  
Vol 132 (7) ◽  
pp. 727-735 ◽  
Author(s):  
Michio Tamate ◽  
Tamiko Sasaki ◽  
Akio Toba ◽  
Yasushi Matsumoto ◽  
Keiji Wada ◽  
...  
Keyword(s):  
Insertion Loss ◽  
Power Converters ◽  
Emi Filter

Performance and Reliability of a MEMS-based tunable optical filter operating in the 1565 nm-1525 nm wavelength range

2002 ◽  
Vol 722 ◽  
Author(s):  
T. S. Sriram ◽  
B. Strauss ◽  
S. Pappas ◽  
A. Baliga ◽  
A. Jean ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Line Width ◽  
Insertion Loss ◽  
Optical Filter ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Reliability Testing ◽  
Silicon Nitride Membrane ◽  
Tunable Optical Filter ◽  
Extensive Performance

AbstractThis paper describes the results of extensive performance and reliability characterization of a silicon-based surface micro-machined tunable optical filter. The device comprises a high-finesse Fabry-Perot etalon with one flat and one curved dielectric mirror. The curved mirror is mounted on an electrostatically actuated silicon nitride membrane tethered to the substrate using silicon nitride posts. A voltage applied to the membrane allows the device to be tuned by adjusting the length of the cavity. The device is coupled optically to an input and an output single mode fiber inside a hermetic package. Extensive performance characterization (over operating temperature range) was performed on the packaged device. Parameters characterized included tuning characteristics, insertion loss, filter line-width and side mode suppression ratio. Reliability testing was performed by subjecting the MEMS structure to a very large number of actuations at an elevated temperature both inside the package and on a test board. The MEMS structure was found to be extremely robust, running trillions of actuations without failures. Package level reliability testing conforming to Telcordia standards indicated that key device parameters including insertion loss, filter line-width and tuning characteristics did not change measurably over the duration of the test.

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