It was recently announced that the planet Mars has at least one thing in common with planet Earth: all good things come to an end. In this case, the good thing is the recently announced and documented (Feb. 12) demise of the Mars rover Opportunity.

Free vibration and dynamic operation testing of hybrid gears at NASA Glenn Spur Gear Fatigue Test Facility; hybrid gears are compared to their steel counterparts.

For the lubrication of open gear drives used in different industrial applications such as cement and coal mills, rotary furnaces, or where the sealing conditions are difficult, semi-fluid greases are often used in preference to fluid oils. For girth gear applications the greases are used with a splash or spray lubrication system. The selection of such greases influences pitting lifetime and the load-carrying capacity of the gears, as well as wear behavior