MBOD People Research Publications Collaborators Contact
boat

Oh snap! We just showed you a modal..

Because we can

Cool huh? Ok, enough teasing around..

Go to our W3.CSS Tutorial to learn more!

Ongoing projects

Mechanical Biomimetics

Ecological pressure and natural selection lead to clever manipulation of materials, geometry, and forces toward crucial function. We are interested in principles underlying natural solutions and how they may be directed toward pressing human problems, especially those of sustainability.

In coastal deserts, moist air can frequently blow over dry land, without ever coalescing or precipitating down on the surface. These regions often also suffer economic hardship and lack of infrastructure, such that harnessing airborne moisture can be a basis for life. Humans have spent some decades developing meshes to intercept and collect fog. The living world has spent eons whimsically mixing physical and chemical mechanisms. A Namib desert beetle, which collects fog from the morning wind atop sand dunes near the coast, has raised the prospect of transformative biomimetic solutions, but nearly all research has focused on the surface transport mechanism, particularly with respect to wettability. We are investigating the fluid dynamics of the other crucial step: droplet interception before coalescence and collection, focusing on the role of surface morphology (ie. bumps like those of beetle elytra) and non-trivial flow geometries, to find new angles on improved collection efficiency, and insight into the antithetical problem of icing in flight and wind power.

Fluid dynamics of bio-inspired fog collection

A cardinal will use its own body as template in building its cup-nest. Found, filamentous material are added and randomly packed against the bird-defined boundaries. The resulting structure will not be very stiff, but it will reliably hold its shape, enough to protect its valuable contents against various disturbances. This seemingly simple, naturally-selected engineering solution for keeping one’s offspring safe, is instead the result of a subtle interplay between geometry, topology, elasticity, and friction. Using experimental approaches adapted from granular physics, and in close collaboration with simulators at UIUC, we are characterizing the emergent quasi-static and dynamic mechanical behavior of "nest" materials, and their dependence on constituent fiber properties and the distribution of their disordered, impermanent contacts.

Emergent mechanics of the artificial "bird nest"

The ant Philidris nagasau sows and maintains its plant-hosts (Squamellaria) in the trees of Fiji. In return, squamellaria offer both food and ready-made housing in an obligate mutualist relationship: the ants cannot build their own nests, and the plants do not propagate on their own. The strategy involves conflicting goals: squamellaria planted high in the canopy give more sugar, but exposure to high temperatures can harm ant broods. The morphologically distinct, farmed (specialized) Squamellaria appear to be cooler than their non-ant-farmed (generalist) counterparts when exposed to the same conditions. In order to extract the evolved, architectural design principle(s) responsible for this passive thermoregulation, we are developing and deploying custom sensor modules to thoroughly document, in-situ, relevant heat transfer parameters and exploring minimal models for leading-order mechanisms.

Thermoregulation in a plant ant-house

Open Design

The lab explores bridges between open-source, DIY, maker methods, those of academic laboratory, and citizen science. This effort reaches from both ends: minimally implementing conventional laboratory technique for broader and interdisciplinary purposes; also developing and rigorously testing ideas from open-source communities.

With the increasing stresses of nutrient loading and climate change, engagement of local communities in monitoring and stewardship of their water resources will be vital. Minimal, inexpensive, and accurate-enough devices can facilitate that engagement and connect schools, volunteer groups, and the environmental research community. The lab is currently developing a smart-phone based, pedagogic tool, based on the optics and chemistry of conventional spectroscopic methods, to measure nitrate and phosphate concentrations.

Open-source hardware for water quality monitoring

Past projects

Many termite species live in large colonies and harvest fungus to supplement nutrition. Living underground keeps them cool and protected, but creates a serious issue for respiration. The tall mounds that protrude above the nests are effectively lungs, which harness oscillations of ambient temperature to drive bulk flow between the nest and mound, while gases exchange via diffusion through the porous walls. Mound architecture amplifies transient thermal gradients along connected conduits to facilitate the internal convection, in an inspirational example of emergent engineering.

Physics of termite mound respiration

When a thin sheet is compressed in one thin direction, it readily buckles outward, demonstrating the relative ease in storing energy in bending rather than in-plane stresses. If the sheet is adhered to a soft (or liquid) substrate, the same Euler instability leads to a pattern of smooth wrinkles, caused by competition between the bending modulus of the sheet and the stiffness (or weight) of the substrate. This buckling motif fundamentally differs from that observed when one crumples a piece of paper: pointy cusps connected by ridges. The sharpness in the crumpled shape illustrate the phenomenon of stress focusing, in which the sheet chooses to concentrate elastic energy in small regions in response to confinement from the boundaries. By confining a flat sheet to a slightly, variably curved, liquid meniscus and optically measuring its deformation, we tested predictions for wrinkle extent in the simplest case of non-uniform confinement, and discovered a generic route by which a featureless sheet assumes a crumpled shape.

Wrinkling and crumpling of thin sheets

People


Boss

Aida Shahrokhian

Polymers PhD student

Boss

Nicholas Weiner

Polymers PhD student

Boss

Mengyue Sun

Polymers PhD student

Boss

Meron Dibia

Integrated Biosciences PhD student


Boss

Kelly Siman

Biomimicry Fellow

Boss

Jiansheng Feng

Research Scientist

Boss

Yanxi Li

Polymers MS student

Boss

Banafsheh Khakipoor

Biomimicry Fellow (honorary member)


Boss

Hunter King

PI

Publications

  1. S. Ocko*, H. King* D. Andreen, P. Bardunias, R. Soar, J. S. Turner and L. Mahadevan. (2017) Solar-powered ventilation of African termite mounds. Journal of Experimental Biology 10.1242. (Featured in Inside JEB)
  2. H. King. (2016) The superorganism behind nature's skyscraper. Laboratory News (Invited feature)
  3. J. D. Paulsen, E. Hohlfeld, H. King, J. Huang, Z. Qui, T. P. Russell, N. Menon, D. Vella and B. Davidovitch. (2016) Curvature-induced stiffness and the spatial variation of wavelength in wrinkled sheets PNAS 10.1073.
  4. H. King*, S. Ocko* and L. Mahadevan. (2015). Termite mounds harness diurnal temperature oscillations for ventilation PNAS 10.1073. (Publicity: Harvard Magazine, Science News, CBC's As It Happens interview, Boston Globe)
  5. J. Chung, H. King, and L. Mahadevan. (2014). Evaporative microclimate driven hygrometers and hygromotors EPL 107, 64002 (U.S. Patent Application No.: 15/358,025, filed November 21, 2016)
  6. H. King*, R. Schroll*, B. Davidovitch and N. Menon. (2012). A sheet on a drop reveals wrinkling and crumpling as distinct symmetry-breaking instabilities, PNAS (cover) 109.25, 9716-9720. (Publicity: New England Public Radio interview, sciencedaily)
  7. H. King, R. White, I. Maxwell, and N. Menon. (2011). Inelastic impact of a sphere on a massive plane: Nonmonotonic velocity-dependence of the restitution coefficient, EPL 93, 14002.
  8. J. A. Hanna and H. King. (2011). An Instability in a Straightening Chain DFD Gallery of Fluid Motion

Support

Collaborators

  1. Mattia Gazzola -- Mechanical Science and Engineering at University of Illinois, Urbana Champaign
  2. Andres Concha -- Physics at Adolfo Ibañez University, Santiago
  3. Darrell Reneker -- Polymer Science at UAkron
  4. Petra Gruber -- Art and Biology at UAkron
  5. Ali Dhinojwala -- Polymer Science at UAkron
  6. Adam W. Smith -- Chemistry at UAkron
Contact Us

Goodyear Polymer Center

    Department of Polymer Science
    University of Akron
    Akron, OH 44325-3909 

  +1 330-972-6370

  hking@uakron.edu

Vernazza