Natural gears

Optimal Shapes for Gears

| Gear theory is reexamined and we nd optimal shapes for gears. As optimality criteria, we allow: (1) minimal frictional losses (highest eeciency) assuming linear law of friction or (2) uniform maximum stress (it will wear out slowly and last the longest) assuming Hertzian contacts or (3) uniform maximal temperature, assuming we are in a high power limit in which all heat is removed by the lubr...

Condition Indicators for Gears

Diagnostics of faults in gears requires development of reliable condition indicators. A large number of condition indicators, which are based on statistical moments of the synchronous average and its derivatives (difference and residual signals) were previously suggested. This study evaluates the efficiency of different gear condition indicators that are based on statistical moments and compare...

Battery – Motor – Gears Paper

How Bacteria Shift Gears

Bacteria can change course almost instantaneously, zipping towards food or away from toxins. How do such simple organisms do something so complex? It’s all in the flagella, a tail-like structure with rotating helical filaments. The flagella work in unison to propel the cell forward by rotating counterclockwise and thus bundling together. When the flagella reverse their rotation to clockwise, th...

Vibration Health Monitoring of Gears