Arrested Dynamics of Droplet Spreading on Ice.

We investigate the arrested spreading of room temperature droplets impacting flat ice. The use of an icy substrate eliminates the nucleation energy barrier, such that a freeze front can initiate as soon as the droplet's temperature cools down to 0 °C. We employ scaling analysis to rationalize distinct regimes of arrested hydrodynamics.

Development of a Translational Model to Assess the Impact of Opioid Overdose and Naloxone Dosing on Respiratory Depression and Cardiac Arrest.

In response to a surge of deaths from synthetic opioid overdoses, there have been increased efforts to distribute naloxone products in community settings. Prior research has assessed the effectiveness of naloxone in the hospital setting; however, it is challenging to assess naloxone dosing regimens in the community/first-responder setting, including reversal of respiratory depression effects of fentanyl and its derivatives (fentanyls). Here, we describe the development and validation of a mechanistic model that combines opioid mu receptor binding kinetics, opioid agonist and antagonist pharmacokinetics, and human respiratory and circulatory physiology, to evaluate naloxone dosing to reverse respiratory depression.

Using Frost to Promote Cassie Ice on Hydrophilic Pillars.

We develop a novel approach to suspend ice in the air-trapping Cassie state without requiring any fragile hydrophobic coatings or nanostructures. First, frost was preferentially grown on the tops of hydrophilic aluminum pillars due to their sharp corners and elevation over the noncondensable gas barrier. Subsequently, Cassie ice was formed by virtue of the impacting droplets getting arrested by the upper frost tips.

How Multilayered Feathers Enhance Underwater Superhydrophobicity.

Inspired by ducks, we demonstrate that air pockets within stacked layers of porous superhydrophobic feathers can withstand up to five times more water pressure compared to a single feather. In addition to natural duck feathers, this "layer effect" was replicated with synthetic feathers created by laser cutting micrometric slots into aluminum foil and imparting a superhydrophobic nanostructure. It was revealed that adding layers promotes an increasingly redundant pathway for water impalement, which serves to pressurize the enclosed air pockets.

Electrostatic Jumping of Frost.

The electrification of ice has been a subject of research since 1940, mostly in the context of charge generation in thunderstorms. This generation of electric charge is spontaneous, distinct from applying an external electric field to affect the diffusive growth of ice crystals. Here, we exploit the spontaneous electrification of ice to reveal a surprising phenomenon of jumping frost dendrites.

Suppressing Condensation Frosting Using an Out-of-Plane Dry Zone.

The vapor pressure above ice is lower than that above supercooled water at the same temperature. This inherent hygroscopic quality of ice has recently been exploited to suppress frost growth by patterning microscopic ice stripes along a surface. These vapor-attracting ice stripes prevented condensation frosting from occurring in the intermediate regions; however, the required presence of the sacrificial ice stripes made it impossible to achieve the ideal case of a completely dry surface.

A Low-loss and Lightweight Magnetic Material for Electrical Machinery.

A low-loss and lightweight core material, with applications in electrical machinery, is made of highly packed and insulated magnetic microwires (MWs). These MWs are aligned in such a way as to guide the flux in the rotor/stator, with the ultimate goal of increasing efficiency and substantially reducing core losses. Commercial FeNiCo-based MWs with a 127 m diameter and a 33 m insulation coating are utilized.

Guidelines for establishing a 3-D printing biofabrication laboratory.

Advanced manufacturing and 3D printing are transformative technologies currently undergoing rapid adoption in healthcare, a traditionally non-manufacturing sector. Recent development in this field, largely enabled by merging different disciplines, has led to important clinical applications from anatomical models to regenerative bioscaffolding and devices. Although much research to-date has focussed on materials, designs, processes, and products, little attention has been given to the design and requirements of facilities for enabling clinically relevant biofabrication solutions.

How ice bridges the gap.

When supercooled dew droplets form on a chilled surface, the subsequent freezing process is driven by a fascinating phenomenon of propagating inter-droplet ice bridges. Here, we explore the range of conditions under which an individual ice dendrite can successfully bridge the gap from a frozen droplet to its nearest liquid neighbor. Ranging the droplet sizes from 1 μm-10 mm, we find that the criterion for ice bridging is purely geometric and independent of temperature, ambient humidity, and surface wettability.

How soap bubbles freeze.

Droplets or puddles tend to freeze from the propagation of a single freeze front. In contrast, videographers have shown that as soap bubbles freeze, a plethora of growing ice crystals can swirl around in a beautiful effect visually reminiscent of a snow globe. However, the underlying physics of how bubbles freeze has not been studied.

'Sneezing' plants: pathogen transport via jumping-droplet condensation.

We show that condensation growing on wheat leaves infected with the leaf rust fungus, Puccinia triticina, is capable of spontaneously launching urediniospores off the plant. This surprising liberation mechanism is enabled by the superhydrophobicity of wheat leaves, which promotes a jumping-droplet mode of condensation powered by the surface energy released from coalescence events. We found that urediniospores often adhere to the self-propelled condensate, resulting in liberation rates of approximately 10 cm h for leaves infected with rust.

Passive Antifrosting Surfaces Using Microscopic Ice Patterns.

Despite exceptional recent advances in tailoring the wettability of surfaces, to date, no engineered surface can passively suppress the in-plane growth of frost that invariably occurs in humid, subfreezing environments. Here, we show that up to 90% of a surface can exhibit passive antifrosting by using chemical or physical wettability patterns to template "ice stripes" across the surface. As ice exhibits a depressed vapor pressure relative to liquid water, these sacrificial ice stripes siphon the supersaturated water vapor to keep the intermediate surface areas dry from dew and frost.

Tuning Superhydrophobic Nanostructures To Enhance Jumping-Droplet Condensation.

It was recently discovered that condensation growing on a nanostructured superhydrophobic surface can spontaneously jump off the surface, triggered by naturally occurring coalescence events. Many reports have observed that droplets must grow to a size of order 10 μm before jumping is enabled upon coalescence; however, it remains unknown how the critical jumping size relates to the topography of the underlying nanostructure. Here, we characterize the dynamic behavior of condensation growing on six different superhydrophobic nanostructures, where the topography of the nanopillars was systematically varied.