Grain-Size-Governed Shear Failure Mechanism of Polycrystalline Methane Hydrates

Mechanical instability of monocrystalline and polycrystalline methane hydrates

Despite observations of massive methane release and geohazards associated with gas hydrate instability in nature, as well as ductile flow accompanying hydrate dissociation in artificial polycrystalline methane hydrates in the laboratory, the destabilising mechanisms of gas hydrates under deformation and their grain-boundary structures have not yet been elucidated at the molecular level. Here we...

Grain size control in polycrystalline colloidal

Recent experiments on the static and dynamic properties of polycrystalline colloidal solids show a pronounced influence of morphological details. Here we investigate several possibilities to vary systematically one key morphological parameter, namely the average crystallite radius rc of polycrystalline solids. We report measurements of rc as observed by microscopy in well-characterized Yukawa m...

Adaptive modeling of methane hydrates

We consider a computational model for the evolution of methane hydrates in subsurface. Methane hydrates, an ice-like compound abundant in subsea sediments and unstable in standard conditions, are an environmental hazard and simultaneously an energy source. Our multiphysics model includes multiphase multicomponent mass conservation equations and several variants of energy balance equation with o...

UNEP Global Outlook on Methane Gas Hydrates

EXECUTIVE SUMMARY The UNEP Global Outlook on Methane Gas Hydrates seeks to provide policy makers, the general public and the media with a synthesis of aspects of natural, social and applied sciences that relate to this type of natural gas occurrence. With an emphasis on visual media, the Outlook is working to define global methane gas hydrate occurrences in their natural settings and examine th...

Grain Boundaries in Polycrystalline Alumina