Search

Droplets capture an environment-dictated equilibrium state of a liquid material. Equilibrium, however, often necessitates nanoscale interface organization, especially with formation of a passivating layer. Herein, we demonstrate that this kinetics-driven organization may predispose a material to autonomous thermal-oxidative composition inversion (TOCI) and texture reconfiguration under felicitous choice of trigger. We exploit inherent structural complexity, differential reactivity, and metastability of the ultrathin (∼0.7-3 nm) passivating oxide layer on eutectic gallium-indium (EGaIn, 75.5% Ga, 24.5% In w/w) core-shell particles to illustrate this approach to surface engineering. Two tiers of texture can be produced after ca. 15 min of heating, with the first evolution showing crumpling, while the second is a particulate growth above the first uniform texture. The formation of tier 1 texture occurs primarily because of diffusion-driven oxide buildup, which, as expected, increases stiffness of the oxide layer. The surface of this tier is rich in Ga, akin to the ambient formed passivating oxide. Tier 2 occurs at higher temperature because of thermally triggered fracture of the now thick and stiff oxide shell. This process leads to inversion in composition of the surface oxide due to higher In content on the tier 2 features. At higher temperatures (≥800 °C), significant changes in composition lead to solidification of the remaining material. Volume change upon oxidation and solidification leads to a hollow structure with a textured surface and faceted core. Controlled thermal treatment of liquid EGaIn therefore leads to tunable surface roughness, composition inversion, increased stiffness in the oxide shell, or a porous solid structure. We infer that this tunability is due to the structure of the passivating oxide layer that is driven by differences in reactivity of Ga and In and requisite enrichment of the less reactive component at the metal-oxide interface.

Public officials are oath takers and expected to uphold the law, but criminal convictions provide evidence that corruption exists. When public officials violate their oath, these violations evade ethical norms of behavior important to protecting the integrity inherent in the public office. This article synthesizes the literature on public corruption and related fields and presents a conceptual model to help us understand public leader violations of the oath and factors that enable corrupt behavior more broadly. Through an exploratory analysis of news articles and local government websites of examples of federal corruption convictions from the top ten most corrupt juridictions in the United States, this preliminary model finds six factors influence corruption within a jurisdiction at two collective levels: (1) organizational, and (2) institutional. A case study of an independent nonprofit's experience in anti-corruption further informs a claim that corrupt leaders (i.e., oath-takers) often involve and exert corrupt influence on subordinates. Findings on convicted corruptions expands the conceptual model to inform on institutional factors that may mitigate corruption. Failure to act on corruption creates a distributional consequence for society. Public corruption minimizes equal access to public goods and services, diverts public finances for personal gain, and undermines public confidence. [ABSTRACT FROM AUTHOR]