Scholarly Work - Physics
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/3458
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Item A practical method for determining pit depths using X-ray attenuation in EDX spectra(2015-04) Avci, Recep; Davis, Bret H.; Wolfenden, Mark L.; Kellerman, Laura R.; Lucas, Kilean; Martin, Joshua; Deliorman, MuhammedinA practical method has been developed for rapidly determining the depth of a corrosion micro-pit from the path lengths of X rays passing through the walls of the pit on their way to an X-ray detector. The method takes advantage of the attenuation of the Bremsstrahlung and characteristic X-ray radiation accompanying each X-ray spectrum, and the results are verified independently using AFM and the special pit geometry surrounding MnS inclusions in 1018 carbon steel. The method has general validity and is especially valuable in those cases where the pit depth-to-width ratio is too steep to measure using the conventional methods.Item Determination of Landau free-energy parameters by dielectric measurements in the ferroelectric TSCC(1981-05) Bornarel, J.; Schmidt, V. HugoThe authors measured the adiabatic dielectric permittivity epsilon b of tris-sarcosine calcium chloride (TSCC) at 400 Hz near the ferroelectric transition for DC bias fields up to 5000 V cm-1. They found epsilon infinity =4.2+or-0.2, Curie-Weiss constant C+=38.3+or-0.3K, T0=129.4+or-0.1K, and Landau coefficients A=(2.95+or-0.2)*109 V m A-1 s-1 K-1 and B=(3.5+or-0.1)*1015 V m5 A-3 s-3. They observed evidence of an internal bias field as reported previously by others.Item Anomalies of hypersound velocity and attenuation in ferroelectric tris-sarcosine calcium chloride (TSCC) for small-angle and right-angle Brillouinscattering and Brillouin backscattering(1986-07) Wang, J. T.; Schmidt, V. HugoThe Brillouin spectra of ferroelectric tris-sarcosine calcium chloride have been observed using small-angle and right-angle scattering and also backscattering. For different-frequency phonons along the same direction, analogous anomalies in the sound velocity and the attenuation are seen. The smallest angle we have achieved is 7.48°. The temperature and frequency dependences of the sound velocity are discussed. The fact that the linewidth maximum for [001] phonons occurs somewhat below Tc seems to indicate that the anomalies are due to piezoelectric coupling induced by spontaneous polarization below Tc. For [010] phonons the elementary relaxation times which relate to the energy are estimated as τE0=5.25×10−13 sec above Tc and τE0=3.32×10−12 sec below Tc. The phonon attenuations are also estimated and compared with the observed ones. For the [001] phonons the elementary relaxation time is estimated as τ0=5.25×10−14 sec, in good agreement with the value obtained from right-angle Brillouin scattering.