scholarly journals Acoustic emission study of microcracking in 123-type ceramic superconductors

1990 ◽  
Vol 5 (10) ◽  
pp. 2066-2074 ◽  
Author(s):  
T. J. Richardson ◽  
L. C. De Jonghe
Keyword(s):  
Grain Size ◽  
Acoustic Emission ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Ybco Superconductor ◽  
Sintered Ceramic ◽  
Average Grain Size ◽  
Superconducting Compounds ◽  
Emission Study ◽  
Acoustic Emission Study

Acoustic emission from sintered ceramic YBa2Cu3O7−x (YBCO) superconductor pellets provides a direct measure of microcracking behavior during processing. By detection and statistical analysis of acoustic events, the effects of cooling rates, processing atmosphere, average grain size, additives, and grain alignment on microcracking in YBCO have been studied. The onset temperature and duration of acoustic emission during cooling correlate well with the oxygen partial pressure in the furnace. Rapid changes in oxygen partial pressure at constant temperature produce acoustic emission that is characteristic of microcracking. A reported critical grain size for microcracking in sintered polycrystalline YBCO of about 1 μm has been confirmed. Two superconducting compounds, YSrBaCu3O7−x and LaBaCaCu3O7−x with the 123 structure but with smaller crystallographic anisotropy were also examined. Recommendations are made for minimizing microcracking during processing of superconducting ceramics.

Recrystallization of Oxygen Contaminated Al Films

1986 ◽  
Vol 71 ◽  
Author(s):  
G.J. Van Der Kolk ◽  
M.J. Verkerk
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Substrate Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Relative Increase ◽  
Partial Pressures ◽  
Average Grain Size

AbstractAl was evaporated at oxygen partial pressures, PO2, varying between 10−7 and 10−4 Pa on substrates of silicon nitride. The substrate temperature was varied between 20 °C and 250°C. The films were annealed at temperatures up to 500°C.For Al films deposited at 20°C, it was found that the average grain size decreases with increasing oxygen partial pressure. After annealing recrystallization was observed. The relative increase of grain size was less for higher values of pO2. Annealing gave rise to a broad grain size distribution.For Al films deposited at 250°C, the presence of oxygen caused the growth of rough inhomogeneous films. This inhomogeneous structure remained during annealing.

Impedance spectroscopy of grain boundaries in nanophase ZnO

1995 ◽  
Vol 10 (9) ◽  
pp. 2295-2300 ◽  
Author(s):  
J. Lee ◽  
J.-H. Hwang ◽  
J.J. Mashek ◽  
T.O. Mason ◽  
A.E. Miller ◽  
...  
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Electrical Properties ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Grain Boundaries ◽  
Defect Characterization ◽  
Impedance Spectra ◽  
Gas Condensation ◽  
Average Grain Size

Sintered compacts of nanophase ZnO (∼60 nm average grain size, presintered at 600 °C) were made from powders (∼13 nm) prepared by the gas-condensation technique. Impedance spectra were taken as a function of temperature over the range 450–600 °C and as a function of oxygen partial pressure over the range 10−3−1 atm (550 and 600 °C only). The activation energy was determined to be 55 kJ/mole (0.57 eV) and was independent of oxygen partial pressure. The oxygen partial pressure exponent was −1/6. Impedance spectra exhibited nonlinear I-V behavior, with a threshold of approximately 6 V. These results indicate that grain boundaries are governing the electrical properties of the compact. Ramifications for oxygen sensing and for grain boundary defect characterization are discussed.

Acoustic emission study of the mechanical anisotropy of the extruded AZ31 alloy

2009 ◽  
Vol 100 (6) ◽  
pp. 888-891 ◽  
Author(s):  
Patrik Dobroň ◽  
František Chmelík ◽  
Jan Bohlen ◽  
Kerstin Hantzsche ◽  
Dietmar Letzig ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Az31 Alloy ◽  
Mechanical Anisotropy ◽  
Emission Study ◽  
Acoustic Emission Study

scholarly journals Acoustic emission study on the activity of slip and twin mechanisms during compression testing of magnesium single crystals

2016 ◽  
Vol 650 ◽  
pp. 20-27 ◽  
Author(s):  
Daria Drozdenko ◽  
Jan Bohlen ◽  
František Chmelík ◽  
Pavel Lukáč ◽  
Patrik Dobroň
Keyword(s):  
Acoustic Emission ◽  
Single Crystals ◽  
Compression Testing ◽  
Emission Study ◽  
Acoustic Emission Study

scholarly journals Cover Picture: The Sound of Batteries: An Operando Acoustic Emission Study of the LiNiO 2 Cathode in Li–Ion Cells (Batteries & Supercaps 10/2020)

2020 ◽  
Vol 3 (10) ◽  
pp. 961-961
Author(s):  
Simon Schweidler ◽  
Matteo Bianchini ◽  
Pascal Hartmann ◽  
Torsten Brezesinski ◽  
Jürgen Janek
Keyword(s):  
Acoustic Emission ◽  
Li Ion ◽  
Emission Study ◽  
Acoustic Emission Study

scholarly journals The Sound of Batteries: An Operando Acoustic Emission Study of the LiNiO 2 Cathode in Li–Ion Cells

2020 ◽  
Vol 3 (10) ◽  
pp. 965-965
Author(s):  
Simon Schweidler ◽  
Matteo Bianchini ◽  
Pascal Hartmann ◽  
Torsten Brezesinski ◽  
Jürgen Janek
Keyword(s):  
Acoustic Emission ◽  
Li Ion ◽  
Emission Study ◽  
Acoustic Emission Study

Influence of sand grain size and nest microenvironment on incubation success, hatchling morphology and locomotion performance of green turtles (Chelonia mydas) at the Chagar Hutang Turtle Sanctuary, Redang Island, Malaysia

2018 ◽  
Vol 66 (6) ◽  
pp. 356 ◽  
Author(s):  
Taylor A. Stewart ◽  
David T. Booth ◽  
Mohd Uzair Rusli
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Swimming Speed ◽  
Green Turtle ◽  
Chelonia Mydas ◽  
Sand Particle ◽  
Emergence Success ◽  
Sand Grain Size

The nest microenvironment affects hatching and emergence success, sex ratios, morphology, and locomotion performance of hatchling sea turtles. Sand grain size is hypothesised to influence the nest microenvironment, but the influence of sand grain size on incubation of sea turtle eggs has rarely been experimentally tested. At the Chagar Hutang Turtle Sanctuary, Redang Island, Malaysia, green turtle (Chelonia mydas) nests were relocated to sands with different sand grain sizes on a natural beach to assess whether grain size affects nest temperature, oxygen partial pressure inside the nest, incubation success, hatchling morphology and hatchling locomotion performance. Green turtle nests in coarse sand were cooler; however, hatching success, nest emergence success, oxygen partial pressure, incubation length and hatchling size were not influenced by sand particle size. Nests in medium-grained sands were warmest, and hatchlings from these nests were better self-righters but poorer crawlers and swimmers. Hatchling self-righting ability was not correlated with crawling speed or swimming speed, but crawling speed was correlated with swimming speed, with hatchlings typically swimming 1.5–2 times faster than they crawled. Hence, we found that sand particle size had minimal influence on the nest microenvironment and hatchling outcomes.

Acoustic Emission Study on Effect of Stress Triaxiality on Damage Micromechanisms in Near Alpha Titanium Alloy

2009 ◽  
Vol 28 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Jalaj Kumar ◽  
Sony Punnose ◽  
M. Mahesh Kumar ◽  
T. Jayakumar ◽  
Vikas Kumar
Keyword(s):  
Acoustic Emission ◽  
Titanium Alloy ◽  
Stress Triaxiality ◽  
Alpha Titanium ◽  
Emission Study ◽  
Acoustic Emission Study
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