scholarly journals An Ultrasonic Technique for Testing the Orthotropic Symmetry of Polymeric Sheets by Measuring Their Elastic Shear Coupling Coefficients

1990 ◽  
Vol 112 (3) ◽  
pp. 366-371 ◽  
Author(s):  
C. C. Habeger
Keyword(s):  
Ultrasonic Method ◽  
Thin Sheets ◽  
Ultrasonic Technique ◽  
Coupling Coefficients ◽  
Principal Axes ◽  
Self Consistent ◽  
Elastic Shear ◽  
Shear Coupling ◽  
Good Agreement

An ultrasonic method, which allows the determination of the in-plane elastic stiffnesses of thin polymeric sheets, is described. The determination is complete, as it includes the shear coupling coefficients. Sheets are often assumed to display orthotropic symmetry, which means that the shear coupling coefficients are zero along the principal axes. With this technique, the shear coupling coefficients can be independently calculated, and the validity of the orthotropic assumption can be tested. A quantity called the nonorthotropic angle is presented as a coordinate-independent measure of the lack of orthotropic response. Results from a polyester sheet demonstrate that significant nonorthotropic behavior is encountered in commercial plastic sheets. Stiffnesses, calculated from tests conducted on laminated sheets, are shown to be in good agreement with stiffnesses predicted from measurements on individual plies. The technique is argued to be self-consistent and an attempt is made to convince the reader that this is a legitimate way to characterize all the in-plane elastic stiffnesses of thin sheets.

X-ray-Raman-scattering-based EXAFS beyond the dipole limit

2011 ◽  
Vol 19 (1) ◽  
pp. 106-113 ◽  
Author(s):  
Simo Huotari ◽  
Tuomas Pylkkänen ◽  
J. Aleksi Soininen ◽  
Joshua J. Kas ◽  
Keijo Hämäläinen ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Multiple Scattering ◽  
Light Element ◽  
Polycrystalline Diamond ◽  
Real Space ◽  
X Ray ◽  
Self Consistent ◽  
X Ray Absorption ◽  
Good Agreement

X-ray Raman scattering (XRS) provides a bulk-sensitive method of measuring the extended X-ray absorption fine structure (EXAFS) of soft X-ray absorption edges. Accurate measurements and data analysis procedures for the determination of XRS-EXAFS of polycrystalline diamond are described. The contributions of various angular-momentum components beyond the dipole limit to the atomic background and the EXAFS oscillations are incorporated using self-consistent real-space multiple-scattering calculations. The properly extracted XRS-EXAFS oscillations are in good agreement with calculations and earlier soft X-ray EXAFS results. It is shown, however, that under certain conditions multiple-scattering contributions to XRS-EXAFS deviate from those in standard EXAFS, leading to noticeable changes in the real-space signal at higher momentum transfers owing to non-dipole contributions. These results pave the way for the accurate application of XRS-EXAFS to previously inaccessible light-element systems.

Elastic constants of parahydrogen determined by Brillouin scattering

1978 ◽  
Vol 56 (11) ◽  
pp. 1494-1501 ◽  
Author(s):  
P. J. Thomas ◽  
S. C. Rand ◽  
B. P. Stoicheff
Keyword(s):  
Elastic Constants ◽  
Elastic Anisotropy ◽  
Brillouin Scattering ◽  
Direct Determination ◽  
Experimental Measurements ◽  
Frequency Shifts ◽  
Self Consistent ◽  
Good Agreement ◽  
Phonon Calculation

Five single crystals of parahydrogen were grown near the triple point, and their Brillouin spectra examined in known crystal directions. An analysis of the measured frequency shifts of longitudinal and transverse components led to the direct determination of the adiabatic elastic constants at 13.2 K: C11 = 3.34 ± 0.05, C13 = 0.56 ± 0.03, C33 = 4.08 ± 0.06, C44 = 1.04 ± 0.03 kbar. The fifth elastic constant C12 = 1.30 ± 0.05 kbar was evaluated from the relation C11 + C12 = C13 + C33. Values of the following constants were calculated: elastic anisotropy, A = 1.02 ± 0.06, adiabatic bulk modulus, Bs = 1.73 ± 0.04 kbar, and Debye temperature, θD = 111.2 K. All of these values were compared with earlier experimental measurements. The elastic constants were found to be in good agreement with a recent self-consistent phonon calculation by Goldman.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

A Practical Ultrasonic Inspection Method for Detecting and Characterising Defects Found Within Composite Repairs

2018 ◽  
Author(s):  
J Downing ◽  
A Hook
Keyword(s):  
Wall Thickness ◽  
Steel Substrate ◽  
Ultrasonic Method ◽  
Ultrasonic Inspection ◽  
Heat Exposure ◽  
Matrix Cracking ◽  
Ultrasonic Technique ◽  
Inspection Method ◽  
Composite Repairs ◽  
Layered Matrix

Two steel substrate test panels were developed to represent common plate thicknesses found on naval vessels and scanned using the Babcock developed ultrasonic technique. One sample comprised of a series of slotted surface breaking flaws of varying widths and through thicknesses to represent fracturing/cracking. The inspection method detected simulated cracking to a depth of 2mm and 0.5mm in width. The second sample included numerous loss of wall thickness areas of varying diameters and through thicknesses, with the smallest detectable loss of wall thickness being 0.1mm at a 15mm diameter. After proving confidence in detection, there was a need to characterise flaws to provide support and ascertain a repair action. Samples were produced that were subjected to either impact or heat exposure to induce realistic representative damage. The practical ultrasonic method was successfully used to independently characterise between the samples, with induced de-laminations caused by blisters, and multi layered matrix cracking caused by varying levels of projectile impacts, due to their unique morphology.

An Automated Method for the Determination of Serum Calcium with Glyoxal Bis (2-Hydroxyanil)

1967 ◽  
Vol 13 (6) ◽  
pp. 515-520 ◽  
Author(s):  
Genevieve Farese ◽  
Janice L Schmidt ◽  
Milton Mager
Keyword(s):  
Serum Calcium ◽  
Automated Analysis ◽  
Automated Method ◽  
Good Agreement

Abstract A completely automated analysis is described for the determination of serum calcium with glyoxal bis (2-hydroxyanil) solution (GBHA). The method is simple and precise, and the data obtained are in good agreement with results obtained by the manual GBHA procedure.

Sign in / Sign up

Export Citation Format

Share Document