Microstructure and surface texture driven improvement in in-vitro response of laser surface processed AZ31B magnesium alloy (open access)

Microstructure and surface texture driven improvement in in-vitro response of laser surface processed AZ31B magnesium alloy

This article explores the effects of laser surface melting on microstructure and surface topography evolution in AZ31B magnesium alloy.
Date: January 19, 2021
Creator: Wu, Tso-Chang; Joshi, Sameehan; Ho, Yee-Hsien; Pantawane, Mangesh V.; Sinha, Subhasis & Dahotre, Narendra B.
System: The UNT Digital Library
Ultrasound Imaging by Thermally Tunable Phononic Crystal Lens (open access)

Ultrasound Imaging by Thermally Tunable Phononic Crystal Lens

This article demonstrates the detections and mappings of a solid object using a thermally tunable solid-state phononic crystal lens at low frequency for potential use in future long-distance detection.
Date: July 26, 2021
Creator: Jin, Yuqi & Neogi, Arup
System: The UNT Digital Library
Thermally Tunable Acoustic Beam Splitter Based on Poly(vinyl alcohol) Poly(N-isopropylacrylamide) Hydrogel (open access)

Thermally Tunable Acoustic Beam Splitter Based on Poly(vinyl alcohol) Poly(N-isopropylacrylamide) Hydrogel

Article demonstrating a thermally tunable acoustic beam splitter using a poly(vinyl alcohol) poly(N-isopropylacrylamide) hydrogel (PVA-pNIPAM). The nature of PVA-pNIPAM hydrogel offers exceptional temperature-dependent physical properties due to its phase transition around its lower critical solution temperature. The acoustic impedance of the hydrogel can be tuned below, above, or matched to that of water by changing the environmental temperature. An acoustic wave propagating in water can be split into transmitted and reflected components by the PVA-pNIPAM hydrogel slab on varying its angle of incidence. The intensity ratio between the reflected and the transmitted componence can be adjusted by tuning the temperature of the medium. The acoustic beam can be entirely reflected at a temperature corresponding to the matched impedance between hydrogel and water. The beam-splitting behavior was observed for acoustic waves from both a monochromatic wave and broadband pulse source. In addition, the phase of beam split pulses can be reversed by selecting the hydrogel’s operating temperature.
Date: September 13, 2021
Creator: Jin, Yuqi; Zhou, Mi; Choi, Tae-Youl & Neogi, Arup
System: The UNT Digital Library