A5047019239- Arctic and Antarctic ice dynamics
- nanoparticles nucleation surface interactions
- Cryospheric studies and observations
- Climate change and permafrost
- Material Dynamics and Properties
- Climate variability and models
- Fluid Dynamics and Turbulent Flows
- Advanced Thermodynamics and Statistical Mechanics
- Methane Hydrates and Related Phenomena
- Theoretical and Computational Physics
- Solidification and crystal growth phenomena
- Geology and Paleoclimatology Research
- Fluid Dynamics and Thin Films
- Micro and Nano Robotics
- stochastic dynamics and bifurcation
- Lattice Boltzmann Simulation Studies
- Complex Systems and Time Series Analysis
- Icing and De-icing Technologies
- Oceanographic and Atmospheric Processes
- Meteorological Phenomena and Simulations
- Freezing and Crystallization Processes
- Composite Material Mechanics
- Phase Equilibria and Thermodynamics
- Plant Water Relations and Carbon Dynamics
- Advanced Materials and Mechanics
Yale University
2016-2025
Stockholm University
2016-2025
Whitney Museum of American Art
2025
KTH Royal Institute of Technology
2015-2024
Nordic Institute for Theoretical Physics
2011-2024
Planetary Science Institute
2022-2024
Applied Mathematics (United States)
2010-2023
Indian Institute of Technology Bombay
2023
University of Oxford
2013-2020
University of New Haven
2014-2020
The surface of ice exhibits the swath phase-transition phenomena common to all materials and as such it acts an ideal test bed both theory experiment. It is readily available, transparent, optically birefringent, probing in laboratory does not require cryogenics or ultrahigh vacuum apparatus. Systematic study reveals range critical phenomena, equilibrium nonequilibrium phase-transitions, and, most relevant this review, premelting, that are traditionally studied more simply bound solids....
Several mechanisms can extend the equilibrium domain of a liquid phase into solid region normal diagram. The causes premelting, which include surface melting, interface curvature and substrate disorder, occur in all types substances, including H2O. In case H2O, premelting have important environmental consequences, among are heaving frozen ground, breakdown rock concrete, sintering snow, flow glaciers, scavenging atmospheric trace gases by snow ice, electrification thunderclouds. article...
Our understanding of the ``long range'' electrodynamic, electrostatic, and polar interactions that dominate organization small objects at separations beyond an interatomic bond length is reviewed. From this basic-forces perspective, a large number systems are described from which one can learn about these organizing forces how to modulate them. The many practical harness nanoscale then surveyed. survey reveals not only promise new devices materials, but also possibility designing them more...
Droplets deform soft substrates near their contact lines. Using confocal microscopy, we measure the deformation of silicone gel due to glycerol and fluorinated-oil droplets for a range droplet radii substrate thicknesses. For all droplets, takes universal shape close line that depends on liquid composition, but is independent size thickness. This determined by balance interfacial tensions at provides novel method direct determination surface stresses substrates. Moreover, change in angle...
Numerous cell types have shown a remarkable ability to detect and move along gradients in stiffness of an underlying substrate—a process known as durotaxis. The mechanisms durotaxis are still unresolved, but generally believed involve active sensing locomotion. Here, we show that simple liquid droplets also undergo By modulating substrate stiffness, obtain fine control droplet position on soft, flat substrates. Unlike other mechanisms, works without imposing chemical, thermal, electrical, or...
Frost heave is the process by which freezing of water-saturated soil causes deformation and upward thrust ground surface. We describe fundamental interactions between phase change fluid flow in partially frozen, saturated porous media (soils) that are responsible for frost heave. Water remains only frozen a medium at temperatures below C owing both to depression temperature curved boundaries interfacial premelting caused long-range intermolecular forces. show while former contributes...
The effect of impurities on the surface and interfacial melting ice is investigated in context Derjaguin-Landau-Verwey-Overbeek theory by calculating van der Waals Coulombic interactions within solution films. At high temperatures, classical solute dominates behavior. However, depending amount impurity, as temperature decreases slope film-thickness versus curve changes a manner that depends relative strengths interactions. results explain wide range experimental discrepancies hence impact...
In light of the rapid recent retreat Arctic sea ice, a number studies have discussed possibility critical threshold (or “tipping point”) beyond which ice–albedo feedback causes ice cover to melt away in an irreversible process. The focus has typically been centered on annual minimum (September) cover, is often seen as particularly susceptible destabilization by feedback. Here, we examine central physical processes associated with transition from ice-covered ice-free Ocean conditions. We show...
When the free surfaces of most solids approach their bulk melting temperatures from below, molecular structure material gives way to a disordered with some attributes both solid and liquid phases. temperature is sufficiently close that transition, surface melts literally flows as viscous fluid. This phenomenon, called interfacial premelting, lies at heart microscopic theory matter, captures interest condensed matter physicists physical chemists alike. The process ubiquitous responsible for...
We describe a series of laboratory experiments in which aqueous salt solutions were cooled and solidified from above. These serve as model systems metallic castings, magma chambers sea ice. As the freeze they form matrix ice crystals interstitial brine, called mushy layer. The brine initially remains confined to Convection interior layer begins abruptly once depth exceeds critical value. principal path for expelled is through ‘brine channels’, vertical channels essentially zero solid...
Sea ice is a two‐phase, two‐component, reactive porous medium: an example of what known in other contexts as mushy layer. The fundamental conservation laws underlying the mathematical description layers provide robust foundation for prediction sea‐ice evolution. Here we show that general equations describing reduce to model Maykut and Untersteiner (1971) under same approximations employed therein.
Eshelby's theory of inclusions has wide-reaching implications across the mechanics materials and structures including theories composites, fracture, plasticity. However, it does not include effects surface stress, which recently been shown to control many processes in soft such as gels, elastomers biological tissue. To extend materials, we consider liquid within an isotropic, compressible, linear-elastic solid. We solve for displacement stress fields around individual stretched inclusions,...
We use highly resolved numerical simulations to study turbulent Rayleigh-B\'enard convection in a cell with sinusoidally rough upper and lower surfaces two dimensions for $\mathrm{Pr}=1$ $\mathrm{Ra}=[4\ifmmode\times\else\texttimes\fi{}1{0}^{6},3\ifmmode\times\else\texttimes\fi{}1{0}^{9}]$. By varying the wavelength $\ensuremath{\lambda}$ at fixed amplitude, we find an optimal ${\ensuremath{\lambda}}_{\mathrm{opt}}$ which Nusselt-Rayleigh scaling relation is...
Deforming a porous material can squeeze out interstitial fluid, as we know from washing with kitchen sponge. Many of these materials, including soils, gels, and biological tissues, are soft experience very large deformations, which require complex, highly nonlinear mathematical models. The authors discuss an exact kinematic model for show when how deformations change the mechanics two example problems. Their findings lend deep physical perspective to applications ranging biomedical...
We calculate the van der Waals contribution to surface free energy of ice-water-substrate systems as a model for interfacial melting. The result each substrate is excess per unit area F(L) function thickness L hypothetical water layer between ice and substrate. A minimum in this funciton L\ensuremath{\rightarrow}\ensuremath{\infty} necessary condition complete melting, equivalent wetting at melting point. Retarded potential effects ensure that fulfilled large L, consequence relative...
We describe an experimental test of a new theory the unidirectional freezing aqueous colloidal suspensions. At low speeds planar ice lens completely rejects particles, forming steady-state compacted boundary layer in liquid region. higher interface becomes thermodynamically unstable and breaks down geometrically to trap bulk regions colloid within. The theoretical stability threshold is determined experimentally, thereby demonstrating that suspensions can be treated analogously atomic or...
Antifreeze proteins (AFPs) evolved in many organisms, allowing them to survive cold climates by controlling ice crystal growth. The specific interactions of AFPs with determine their potential applications agriculture, food preservation and medicine. control the shapes crystals a manner characteristic particular AFP type. Moderately active cause formation elongated bipyramidal crystals, often seemingly defined facets, while hyperactive produce more varied shapes. These different morphologies...
We present a physically intuitive model of ice-lens formation and growth during the freezing soils other dense, particulate suspensions. Motivated by experimental evidence, we consider an ice-filled crack in soil. At low temperatures, ice exerts large pressures on walls that will eventually cause to split open. show then propagate across soil form new lens. The process is controlled two factors: cohesion geometrical supercooling water soil, concept introduced measure energy available When...
Recent studies have argued that global warming is responsible for a wavier jet stream, thereby driving midlatitude extreme flooding and drought. Polar amplification—the relative enhancement of high-latitude temperatures under warming—is to be the principal climate state extremes. Namely, decreased meridional temperature gradient suppresses mean zonal winds, leading jets. However, although observations are consistent with such linkage, detailed dynamical mechanism still debated. Here, we...
We present new experimental results relating to the growth and evolution of sea ice. These show, in particular, that brine initially remains trapped interstices ice, only draining into underlying ocean once depth sea-ice layer exceeds a critical value. A general theory for convection within mushy layers is applied develop hypothesis when drainage occurs, which tested against results.
The presence of a substrate can alter the equilibrium state another material near their common boundary. Examples include wetting and interfacial premelting. In latter case, temperature gradients induce spatial variations in thickness premelted film that reflect changes strength repulsion between solid. We show net thermomolecular force on macroscopic is equivalent to thermodynamic buoyancy force-proportional mass solid occupy volume enclosed by gradient.