Morphology and Size of Bacterial Colonies Control Anoxic Microenvironment Formation in Porous Media.

Bacterial metabolisms using electron acceptors other than oxygen (e.g., methanogenesis and fermentation) largely contribute to element cycling and natural contaminant attenuation/mobilization, even in well-oxygenated porous environments, such as shallow aquifers.

Comparative assessment of continuum-scale models of bimolecular reactive transport in porous media under pre-asymptotic conditions.

We compare the ability of various continuum-scale models to reproduce the key features of a transport setting associated with a bimolecular reaction taking place in the fluid phase and numerically simulated at the pore-scale level in a disordered porous medium. We start by considering a continuum-scale formulation which results from formal upscaling of this reactive transport process by means of volume averaging. The resulting (upscaled) continuum-scale system of equations includes nonlocal integro-differential terms and the effective parameters embedded in the model are quantified directly through computed pore-scale fluid velocity and pore space geometry attributes.

Chemical Mass Production of Graphene Nanoplatelets in ∼100% Yield.

Successful application of graphene is hampered by the lack of cost-effective methods for its production. Here, we demonstrate a method of mass production of graphene nanoplatelets (GNPs) by exfoliation of flake graphite in the tricomponent system made by a combination of ammonium persulfate ((NH4)2S2O8), concentrated sulfuric acid, and fuming sulfuric acid. The resulting GNPs are tens of microns in diameter and 10-35 nm in thickness.

Three-dimensional patterning of solid microstructures through laser reduction of colloidal graphene oxide in liquid-crystalline dispersions.

Graphene materials and structures have become an essential part of modern electronics and photovoltaics. However, despite many production methods, applications of graphene-based structures are hindered by high costs, lack of scalability and limitations in spatial patterning. Here we fabricate three-dimensional functional solid microstructures of reduced graphene oxide in a lyotropic nematic liquid crystal of graphene oxide flakes using a pulsed near-infrared laser.