Report on Laminations in Plates - An Acoustical Method for Determination of

1936 ◽  
Author(s):  
NAVAL RESEARCH LAB WASHINGTON DC
Keyword(s):  
Acoustical Method

Determination of Physical Properties of Isotropic Porous Materials by Impedance Tube

2009 ◽  
Author(s):  
Sanjay Sharma ◽  
Dennis Siginer
Keyword(s):  
Porous Medium ◽  
Fluid Flow ◽  
Physical Properties ◽  
Porous Materials ◽  
Low Frequency ◽  
Permeability Measurement ◽  
Impedance Tube ◽  
Acoustical Properties ◽  
Acoustical Method

Simulation of fluid flow in porous materials depends upon the accuracy of permeability measurement. This study details the development of an acoustical method to determine permeability of porous medium. Standardized acoustical testing for low frequency using impedance tube is carried out to determine the acoustical properties of the fibers. Physical properties of porous medium are determined by reverse calculation from the acoustical properties. The acoustical method is validated by comparing the measured acoustical properties of the porous medium by the analytical method. A variety of foams and fibers are tested using this methodology.

scholarly journals Determination of the gas constant by an acoustical method

Nature ◽  
1974 ◽  
Vol 250 (5463) ◽  
pp. 218-218 ◽  
Author(s):  
T. J. QUINN ◽  
T. R. D. CHANDLER ◽  
A. R. COLCLOUGH
Keyword(s):  
Acoustical Method

A new determination of the gas constant by an acoustical method

1976 ◽  
Vol 283 (1314) ◽  
pp. 367-420 ◽  
Keyword(s):  
Pressure Range ◽  
Velocity Of Sound ◽  
Velocity Measurements ◽  
Acoustical Method

A new determination of the gas constant has been made using a method in which the velocity of sound in argon was measured by means of an acoustic inteferometer operated at a temperature close to 273.16 K. Ninety-eight independent velocity measurements were made over a pressure range from 30 to 200 kPa to enable the velocity at zero pressure to be deduced by extrapolation. By using this experimental value, a new value for the gas constant of 8315.73 + 0.17 J K _1kmol_1 was deduced. This is higher than the old value for R , obtained from measurements of the density oi oxygen, by 159 p.p.m. (parts/106).

scholarly journals Combined optical and acoustical method for determination of thickness and porosity of transparent organic layers below the ultra-thin film limit

2011 ◽  
Vol 82 (10) ◽  
pp. 103111 ◽  
Author(s):  
K. B. Rodenhausen ◽  
T. Kasputis ◽  
A. K. Pannier ◽  
J. Y. Gerasimov ◽  
R. Y. Lai ◽  
...  
Keyword(s):  
Thin Film ◽  
Organic Layers ◽  
Acoustical Method ◽  
Ultra Thin Film

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

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