Finite element analysis of fault bend influence on stick-slip instability along an intra-plate fault

Earthquakes have been recognized as resulting from stick-slip frictional instabilities along the faults between deformable rocks. A three-dimensional finite-element code for modeling the nonlinear frictional contact behaviors between deformable bodies with the node-to-point contact element strategy has been developed and applied here to investigate the fault geometry influence on the nucleation and development process of the stick-slip instability along an intra-plate fault through a typical fault bend model, which has a pre-cut fault that is artificially bent by an angle of 5.6degrees at the fault center. The numerical results demonstrate that the geometry of the fault significantly affects nucleation, termination and restart of the stick-slip instability along the intra-plate fault, and all these instability phenomena can be well simulated using the current finite-element algorithm.

40Ar/39Ar geochronology of gold mineralization in Brasiliano strike-slip shear zones in the Barborema province, NE Brazil

40Ar/39Ar geochronology of muscovite and biotite grains genetically related to gold and Be–Ta–Li pegmatites from the Seridó Belt (Borborema province, NE Brazil) yield well-defined, reliable plateau ages. This information, combined with data about paragenetic and field relationships, reveals Cambro-Ordovician mineralization ages (520 and 500–506 Ma) for the orogenic gold deposits in the Seridó Belt. Biotite ages of 525±2 Ma, which represent the mean weighted results of the incremental heating analysis of six biotite single crystals, record the time of pegmatite emplacement and reactivation of Brasiliano/Pan-African strike-slip shear zones. These results, along with previous structural evolution studies, suggest that shear zones formed during the Brasiliano/Pan-African event were reactivated in the Upper Cambrian–Lower Ordovician. Mineralization occurs late in the history of the orogen.

Unsafe driving behaviour and four wheel drive vehicles: observational study

Objective To assess the level of compliance with the new law in the United Kingdom mandating penalties for rising a hand held mobile phone while driving, to compare compliance with this law with the one on the use of seat belts, and to compare compliance with these laws between drivers of four wheel drive vehicles and drivers of normal cars. Design Observational study with two phases-one within the grace period, the other starting one week after penalties were imposed on drivers using such telephones. Setting Three busy sites in London. Participants Drivers of 38 182 normal cars and 2944 four wheel drive vehicles. Main outcome measures Proportions of drivers seen to be using hand held mobile phones and not using seat belts. Results Drivers of four wheel drive vehicles were more likely than drivers of other cars to be seen using hand held mobile phones (8.2% v 2.0%) and not complying with the law on seat belts (19.5% v 15.0%). Levels of non-compliance with both laws were slightly higher in the penalty phase of observation, and breaking one law was associated with increased likelihood of breaking the other. Conclusions The level of non-compliance with the law on the use of hand held mobile phones by drivers in London is high, as is non-compliance with the law on seat belts. Drivers of four wheel drive vehicles were four times more likely than drivers of other cars to be seen using hand held mobile phones and slightly more likely not to comply with the law on seat belts.

Entropy generation for microscale forced convection: effects of different thermal boundary conditions, velocity slip, temperature jump, viscous dissipation, and duct geometry

This work presents closed form solutions for fully developed temperature distribution and entropy generation due to forced convection in microelectromechanical systems (MEMS) in the Slip-flow regime, for which the Knudsen number lies within the range 0.001