The performance of an active system, whether it is optical, electrical, or mechanical, is often described by its quality ( Q ) factor. Typically, one learns the rule that the higher the Q factor, the sharper the resonance?that is, the bandwidth of the device is reduced. Tsakmakidis et al.
The Roomba 650 Vacuuming Robot provides a thorough clean, all at the push of a button. The patented, 3-Stage Cleaning System easily picks up dust, pet hair and large debris like cereal. Preset Roomba to clean when it?s convenient for you, so you can keep up with everyday mess.
An ancient river erodes the landscape in Namibia.
PHOTO: ERIC NATHAN/ALAMY STOCK PHOTO
Earth, Mars, and Titan have all hosted rivers at some point in their histories. Rivers erode the landscape, leaving behind signatures that depend on whether the surface