Forced sound transmission through a finite-sized single leaf panel subject to a point source excitation

2018 ◽  
Vol 143 (3) ◽  
pp. 1567-1577
Author(s):  
Chong Wang
Keyword(s):  
Point Source ◽  
Sound Transmission ◽  
Single Leaf ◽  
Source Excitation

Microphotometry of Underwater Shadowing by a Moss from a Niagara Escarpment Waterfall

2010 ◽  
Vol 17 (1) ◽  
pp. 125-131
Author(s):  
Howard J. Swatland
Keyword(s):  
Point Source ◽  
Single Cells ◽  
Incident Light ◽  
Polarized Light ◽  
Specular Reflectance ◽  
Light Spectra ◽  
Niagara Escarpment ◽  
Single Leaf ◽  
Diffuse Illumination ◽  
Air Water Interface

AbstractMicroscope and fiber-optic spectrophotometry of transmittance and backscattering both showed moss leaves to be capable of casting strong shadows, with a single leaf blocking approximately 90% of incident light from a point source. In leaves with only one layer of cells, the transmittance through the cytoplasm of single cells was similar to that for whole leaves. Analysis of cell wall birefringence by polarized-light interferometry indicated that cell walls might normally scatter rather than transmit light. Spectra transmitted through, or backscattered from, the upper green layers of moss were dominated by selective absorbance from chlorophyll, but there was also evidence of wavelength-dependent scattering, as detected in the lower layers of brown, dead moss. Specular reflectance from moss leaves was detected by polarimetry and may have contributed to the relatively high macroscopic transmittance of stationary moss in water. Shadowing by moss leaves was confirmed by dynamic measurements of mosses in turbulent water without bubbles. Flicker patterns from leaves were superimposed on the underwater flicker pattern created at the air-water interface, thus flecks of light were reduced in intensity, increased in frequency, and decreased in duration. This was detected with both point source and diffuse illumination of samples.

Effect of porous material compression on the sound transmission of a covered single leaf panel

2012 ◽  
Vol 73 (8) ◽  
pp. 791-797 ◽  
Author(s):  
B. Campolina ◽  
N. Dauchez ◽  
N. Atalla ◽  
O. Doutres
Keyword(s):  
Porous Material ◽  
Sound Transmission ◽  
Single Leaf

Radiation patterns: Possibility for monitoring seismic sources

Geophysics ◽  
1996 ◽  
Vol 61 (1) ◽  
pp. 282-287
Author(s):  
Philip Carrion ◽  
José Carcione ◽  
Edson E. S. Sampaio
Keyword(s):  
Point Source ◽  
Field Measurements ◽  
Seismic Sources ◽  
Seismic Events ◽  
Elastic Media ◽  
Radiation Patterns ◽  
Source Radiation ◽  
Earth Environment ◽  
Source Excitation ◽  
Homogeneous Media

Recent field measurements of the radiation in boreholes indicate that the radiation patterns of real seismic sources are not always in agreement with those corresponding to the point‐source excitation in unbounded homogeneous and isotropic acoustic or elastic media [we refer the reader to Aki and Richards (1980) for the basic discussion on the radiation patterns in homogeneous media]. This mismatch results from the fact that the point‐source radiation patterns corresponding to homogeneous media are too simplistic to satisfy any experiment in the more realistic Earth environment. A study of radiation patterns is certainly important not only to predict possible seismic events but also to analyze the source performance itself by recording seismic arrivals.

Scattering relations for point-source excitation in chiral media

2005 ◽  
Vol 29 (1) ◽  
pp. 27-48 ◽  
Author(s):  
Christodoulos Athanasiadis ◽  
Nikolaos Berketis
Keyword(s):  
Point Source ◽  
Chiral Media ◽  
Source Excitation
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