z of steel and GFRP (1) are defined as a product of their densities p and acoustic velocity c 
This is due to a better adaptation of acoustic impedances
between the medium and the ceramic, through the glass of the vessel .
We have also observed that some attributes such as P wave, S wave acoustic impedances
and P to S waves velocity ratio (VPNs) have different variation response, when gas hydrates occurred as part of host So it is expected that these results Leeds us to interpret gas hydrates accurately in Makran offshore Pakistan.
Royston, United Kingdom, August 21, 2014 --(PR.com)-- Regulations put pressure on aerospace engineers to improve liner attenuation - and this drives the need for improved acoustic impedances
in jet aircraft acoustic liners.
In the case of single material, the wave is almost reflected when it meets boundaries that have a significant difference in acoustic impedances
(Z) of the materials on each side of the boundary, such as a discontinuity or the back wall [33, 34].
The upstream and downstream acoustic impedances
([Z.sub.u] and [Z.sub.d]) can be determined using a model based on transfer matrix theory (Munjal 1987; Munjal et al.
where: R is the reflecting factor [-]; [Z.sub.1] and [Z.sub.2] are the acoustic impedances
of the materials realising the interface [kg x [m.sup.-2] x [s.sup.-1]].
Not precisely coordinated piezo and the outer surface acoustic impedances
can cause problems with the quality of transmission and reception of the signal and the appearance of false reflections.
In our case, we used simulated annealing to find the optimum number of layers, the length and the acoustic impedances
which give the best fit with an experimental or predicted behavior.
Where [Z.sub.a2] and [Z.sub.a1] are acoustic impedances
of layers 2 and 1 respectively.
The acoustic impedances
of delay line [Z.sub.D] and polymer melt [Z.sub.P] are calculated from Eq.
Instead of relying on the relative indices of refraction to obtain an image of the finger, as optical scanners do, the Series 500 relies on the relative acoustic impedances
between the ridges and valleys of the fingerprint.