Scientists, philosophers, and policymakers disagree about how to define microaggression. Here, we offer a taxonomy of existing definitions, clustering around (a) the psychological motives of perpetrators, (b) the experience of victims, and (c) the functional role of microaggression in oppressive social structures. We consider conceptual and epistemic challenges to each and suggest that progress may come from developing novel hybrid accounts of microaggression, combining empirically tractable features with sensitivity to the testimony of victims.

Recent studies have indicated that droplet evaporation heat transfer can be substantially enhanced by fabricating a thin nanoporous superhydrophilic layer on a metal substrate. Such surfaces have immense potential to improve spray cooling processes, however, little durability testing of the surface has been performed. In spray cooling applications, as water evaporates any impurities in the water will be deposited onto the surface. Primarily, this investigation serves to demonstrate how minerals in hard water deposit on the surface and interact with the ZnO nanopillars of the superhydrophilic surface. Quantifying the effects of mineral scale on droplet spreading and vaporization heat transfer on the surface is important in determining implementation requirements to advance the surface into industry applications. Micrographs of the surface demonstrate minerals deposit nonuniformly and quickly fill the nanostructure. Despite a reduction in the extent of droplet spreading due to the mineral deposition, scaled surfaces still demonstrated improved thermal performance compared to an uncoated, smooth copper surface. Scale tended to build up on previously deposited scale, leaving largely uncoated areas where droplets chose to preferentially spread and resulting in a continued low contact angle. Maintaining these uncoated areas and reducing the contaminants present in the water will extend the life and performance of the nanostructured surface.

Microaggressions are seemingly negligible slights that can cause significant damage to frequently targeted members of marginalized groups. Recently, Scott O. Lilienfeld challenged a key platform of the microaggression research project: what's aggressive about microaggressions? To answer this challenge, Derald Wing Sue (the psychologist who has spearheaded the research on microaggressions) needs to theorize a spectrum of aggression that ranges from intentional assault to unintentional microaggressions. I suggest turning to Bonnie Mann's "Creepers, Flirts, Heroes and Allies" for inspiration. Building from Mann's richer theoretical framework will allow Sue to answer Lilienfeld's objection and defend the legitimacy of the concept, 'microaggression'.

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Recent studies of droplet spreading on nanostructured surfaces have demonstrated that the fluid motion and wicking effects impact the morphology of the liquid on the nanostructured surface and the thermophysics of the vaporization process. In the investigation summarized here, models of the spreading mechanism, and mechanisms of heat transport to the interface of a spreading droplet are used to explore the interaction of these mechanisms during the droplet vaporization process on nanostructured hydrophilic surfaces. Exploration of the trends in the model predictions and their comparison with experimental data suggests that the wickability of such surfaces causes an impinging droplet to quickly spread to form a thin liquid film with a somewhat curved interface. This liquid film has a mean thickness in the range of 10–100 microns near the contact line at the outer perimeter of the droplet footprint. If the surface is highly superheated, bubble nucleation and a nucleate boiling mechanism may augment conduction across the liquid film to facilitate evaporation. However, physical arguments and data from droplet evaporation experiments suggest that nucleation in the interstitial spaces of the nanoporous layer may be suppressed as a result of the extremely small size of those spaces. The role of these different mechanisms and the stages of the vaporization process for impinging droplets is discussed in detail. This exploration indicates that the wickability effect on droplet spreading strongly enhances the droplet evaporation heat transfer.