This study demonstrated circular surface nanostructures and femtosecond laser-induced periodic surface structures (FLIPSS) for copper produced by a Ti:Sapphire femtosecond laser beam of wavelength 800 nm and duration 120 fs. The circular textured nanostrucres could be created by a single laser pulse. The nanostructures in the center of the heated spot diminish as laser fluence increases and a c...

Zircon and apatite crystals from the western Canadian shield yield (U-Th)/He dates that are the oldest yet reported for terrestrial rocks. Zircon dates from 1.73 to 1.58 Ga are consistent with independent geological and thermochronological constraints, and indicate that the rocks were at temperatures 180 C and crustal depths 7–10 km since ca. 1.7 Ga. Apatite dates from 0.95 to 0.55 Ga suggest r...

[1] We used dense linear seismic arrays across and along the San Andreas Fault (SAF) at Parkfield, California to record fault zone trapped waves generated by explosions and microearthquakes in 2002. Prominent trapped waves appeared at stations close to the SAF main fault trace while some energy was trapped in the north strand at the array site. Observations and 3-D finitedifference simulations ...

The plate boundary and major crustal blocks in southern California are imaged by a tomographic backprojection of the Pg first arrivals recorded by the Southern California Array. The method, formulated specifically for local earthquake arrival times, is a fast, iterative alternative to direct least-squares techniques. With it, we solve the combined problem of determining refractor velocity pertu...

This paper investigates experimentally the effect of compressed cold air (CCA) and vegetable oil on the surface integrity and residual tresses of ground tool steel components. It shows that CCA can reduce grinding temperature and produce a compressive residual stress up o the grinding depth of 30 m. CCA can also improve surface finish while keeping grinding forces low. Oil was found to be more ...