A molecular dynamics study on the mechanical response of thermal-pressure rejuvenated CuxZr100-x metallic glasses.

A molecular dynamics study was performed on the mechanical response of thermal-pressure rejuvenated CuxZr100-x metallic glasses. The effect of temperature (50, 300, 600 K) and pressure (0-50 GPa) on the rejuvenation process and the mechanical properties of CuxZr100-x including stress-strain response, shear localization formation and elastic modulus were investigated. The thermal-pressure rejuvenation process involves transitioning the system to a higher potential energy state and a lower atomic volume, demonstrating the significant influence of pressure on rejuvenation. Our findings reveal that increasing pressure at specific temperatures and material compositions results in reduced yield stress and stress drop. They also indicate that with increasing pressure, the system undergoes a transition towards homogeneity, resulting in enhanced ductility compared to its initial amorphous state. Additionally, high temperatures contribute to lower values of Young's, shear, and bulk moduli, as well as decreased yield stress and stress drop. Consequently, the system becomes more homogeneous, promoting rejuvenation. Furthermore, we observed that the final yield strength of the system increases with higher Cu content for all structures at specific pressures and temperatures. The level of rejuvenation is additionally impacted by the amount of Cu, and structures containing varying content of Cu demonstrate varying degrees of rejuvenation. To validate our findings, we utilized Voronoi analysis, which revealed a higher fraction of densely-packed clusters in the samples. Finally, a total of 10 materials properties were calculated and explored using statistical analysis which shows there are different correlations between pressure, temperature and atomic composition with mechanical properties.

Dual functionality of surface plasmon resonance and barrier layer on the photosensing and optical nonlinearity of ZnO nanorod arrays.

The dual functionality of plasmonic light harvesting and barrier spacing between Au nanoparticles (NPs) and ZnO nanorod arrays (NRsA) are spotlighted to investigate their impact on the photoconversion and optical nonlinearity in the present study. The passivating Al2O3 barrier layer permits high-energy hot electron tunneling and injection from Au to the ZnO NRsA. The structural, vibrational, morphological/elemental, and optical properties of ZnO NRsA/a-Al2O3/Au were characterized by X-ray diffraction (XRD), Raman scattering, field emission scanning electron microscopy/energy dispersive X-ray spectroscopy (FE-SEM/EDX), and ultraviolet-visible-near IR (UV-Vis-near IR) absorption, respectively. The optoelectronic and nonlinear optical properties were analyzed by current-voltage measurement and z-scan tests under red laser (655 nm) irradiation, respectively. To highlight the effect of surface plasmon charge transport-based photosensing and photo-harvesting, the irradiated light source is selected to have a photon energy lower than the ZnO bandgap energy and detuning from LSPR. The transfer of photo-induced hot electrons from the Au NPs localized surface plasmon resonance (LSPR) to the ZnO NRsA translates into photocurrent generation in photosensing performance. The reverse saturable absorption process is changed to saturable absorption after intercalating the Al2O3 spacing layer into the ZnO NRsA/Au interface. The typical values of the nonlinear refraction index and absorption coefficient are calculated as n2 = +2.38 × 10-5 cm2 W-1 and ß = -0.17 cm W-1 for the sandwiched ZnO NRsA/Al2O3/Au heterostructure, respectively. The sandwiched ZnO NRsA/amorphous Al2O3/Au heterostructure exhibits strong nonresonant optical nonlinearity, which has an excellent figure of merit for optical switching.

Formaldehyde exposure, acute pulmonary response, and exposure control options in a gross anatomy laboratory.

Formaldehyde exposure, acute pulmonary response, and exposure control options were evaluated in a group of 34 workers in a gross anatomy laboratory. Time-weighted average (TWA) exposure to formaldehyde ranged from 0.07-2.94 parts per million (ppm) during dissecting operations. More than 94% were exposed to formaldehyde in excess of the ceiling value of 0.3 ppm recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The eight-hour TWA exposure of 31.7% of the subjects exceeded the action level of 0.5 ppm set by the Occupational Safety and Health Administration (OSHA). Reported symptoms included irritation of eye (88%), nose (74%), throat (29%), and airways (21%). Forced vital capacity (FVC) and forced expiratory volume in 3 seconds (FEV3) decreased, and FEV1/FVC increased during the exposure. The changes of FEV3 were statistically different from those of the controls. The results strongly support the necessity for designing and testing special local exhaust-ventilated worktables with necessary flexibility for dissecting operations.