There are two main challenges in the discovery of new high pressure phases (HPPs) and transforming this discovery into technologies: finding conditions to synthesize new HPPs and finding ways to reduce the phase transformation (PT) pressure to an economically reasonable level. Based on the results of pressure-shear experiments in the rotational diamond anvil cell (RDAC), superposition of plasti...

Seismological observations show that many destructive earthquakes nucleate within, or propagate through, thick sequences of carbonates and evaporites. For example, along the Apennines range (Italy) carbonate and evaporite sequences are present at hypocentral depths for recent major earthquakes (5.0oMwo6.3). However, little is known about the frictional properties of these rocks, which are domin...

-Theoretical constraints on the stress-dilation relation for a deforming Coulomb material require v -< 0 if C = 0 and v -< sin-l(Tm/e,n) always, where v is the dilation angle, 0 is the friction angle, C is cohesion, z,, is the maximum shear stress, and a,~ is the mean effective stress. Recent laboratory measurements of friction and dilatancy of simulated fault gouge show that small amplitude sh...

[1] We examine the frictional behavior of a range of lithified rocks used as analogs for fault rocks, cataclasites and ultracataclasites at seismogenic depths and compare them with gouge powders commonly used in experimental studies of faults. At normal stresses of ∼50 MPa, the frictional strength of lithified, isotropic hard rocks is generally higher than their powdered equivalents, whereas fo...

Further developments are described for the dislocation mechanics based constitutive equation analysis previously used to describe the separate dynamic stress-strain behavior of fcc and bcc metal polycrystals. An enhanced hardening and ductility in copper and certain tantalum materials at higher strain rates in split Hopkinson pressure bar tests and in shock loading are attributed to enhanced di...

Along the base of glaciers and ice sheets, the sliding of ice over till depends critically on water drainage. In locations where drainage occurs through Röthlisberger channels, the effective pressure along the base of the ice increases and can lead to a strengthening of the bed, which reduces glacier sliding. The formation of Röthlisberger channels depends on two competing effects: (1) melting ...

A molecular dynamics simulation study on the interfacial strengthening between defected graphene and polypropylene matrix is implemented. As intrinsic defects in single layer graphene, oxidation, Thrower-Stone-Wales(TSW) defect, and Adatom defect are considered. On the transversely isotropic nanocomposites unit cell embedding different defected graphene, transversely isotropic stress-strain rel...

Sn–9Zn solder joints containing Ag nano particles were prepared by mechanically mixing Ag nano particles (0.3, 0.5 and 1 wt%) with Sn–9Zn solder paste. In the monolithic Sn–Zn solder joints, scallop-shaped AuZn3 intermetallic compound layers were found at their interfaces. However, after the addition of Ag nano particles, an additional uniform AgZn3 intermetallic compound layer well adhered to ...