Measurements of the dielectric and viscoelastic constants in mixtures of 4,4′-n-octyl-cyanobiphenyl and biphenyl

2014 ◽  
Vol 89 (3) ◽  
Author(s):  
Patrick Oswald ◽  
Camille Scalliet
2019 ◽  
Vol 24 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Kumar Vemaganti ◽  
Sandeep Madireddy ◽  
Sayali Kedari

2009 ◽  
Vol 46 (3) ◽  
pp. 268-274 ◽  
Author(s):  
M. J. Birch ◽  
P. D. Srodon

Objective: To measure biomechanical properties of the human soft palate and the variation across anatomic regions. Design: Ex vivo analysis of human tissue. Patients/participants: Ten palates harvested from 10 normal adult human cadavers (age range, 37 to 90 years). Interventions: Computer-controlled uniaxial stress-relaxation mechanical properties tested in physiological saline at 37°C. Main Outcome Measures: Measurement of Young modulus, Poisson ratio, and determination of viscoelastic constants c, τ1, and τ2 by curve-fitting of the reduced relaxation function to the data. Results: One hundred sections were tested from the 10 palates, representative of 10 anatomic zones. The mean Young modulus range was 585 Pa at the posterior free edge to 1409 Pa at regions of attachment. The mean Poisson ratio in the inferior-superior direction was 0.45 (SD 0.26) and in the lateral direction, was 0.30 (SD 0.21). The mean viscoelastic constants for 1-mm extensions were C  =  −0.1056 (±0.1303), τ1  =  11.0369 (±9.1865) seconds, and τ2  =  0.2128 (±0.0792) seconds, and for 2-mm extensions were C  =  −0.1111 (±0.1466), τ1  =  14.3725 (±5.2701) seconds, and τ2  =  0.2094 (±0.0544) seconds. Conclusions: The results show agreement with values of the Young modulus estimated by authors (Ettema and Kuehn, 1994; Berry et al., 1999) undertaking finite element modeling of the palate. However, other modulus measurements based on closing pressure are considerably different. The spatial distribution of viscoelastic parameters across the palate shows good consistency.


1950 ◽  
Vol 23 (1) ◽  
pp. 163-171
Author(s):  
R. S. Witte ◽  
B. A. Mrowca ◽  
E. Guth

Abstract Velocity and attenuation measurements were made in thin strips of rubber from 0.5 to 5 kc and from −5° to 90° C to obtain the dynamic viscoelastic constants of Butyl and GR-S gum stocks. Above room temperature velocity and attenuation are higher in Butyl gum than in GR-S. In all cases, the velocity increases with decreasing temperature and increasing frequency. The attenuation shows a peak with temperature. For Butyl, the peaks are broad and occur at higher temperatures than for GR-S. For both stocks an increase in frequency gives peaks which are higher, sharper, and shifted to higher temperatures. In some instances, there are indications of peaks in the attenuation versus frequency at frequencies beyond our range of measurement. The behavior of the dynamic modulus in the temperature and frequency range studied is similar to that of the velocity. These results, combined with low temperature static measurements and very low frequency dynamic measurements, indicate a U-shaped modulus-temperature curve whose minimum broadens and shifts to higher temperatures with increasing frequency. This may be explained by a generalization of the kinetic theory of rubber elasticity, taking into account intra- and intermolecular forces, and considering time effects.


1964 ◽  
Vol 35 (5) ◽  
pp. 582-586
Author(s):  
Edward L. Spitznagel ◽  
James E. Potzick ◽  
Carmen A. Catanese

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