Abstract: The invention provides an ability to determine a position of a growing plant in a field such that automated or semi-automated means can be deployed more effectively to provide plant maintenance processes during a natural crop cycle. A control system for an agricultural implement may detect detectable elements dispersed between seeds of a seed tape. The control system may determine at least one of a weed zone and a plant zone and may actuate a ground engaging device accordingly.

Abstract: A system for forcibly ventilating a multi-story building connected to a main sewer line includes at least one generally vertical sanitary stack in gaseous communication adjacent the top thereof with atmosphere and adjacent the bottom thereof with a ventilating pipe. The ventilating pipe is in gaseous communication with each stack (below the lowermost sanitary inlet to the stack) for receiving the gaseous content from adjacent the bottom thereof. A stack fan in gaseous communication with each stack adjacent the top thereof forcibly and continuously blows air down the stack to the ventilating pipe, and a pipe fan in gaseous communication with the ventilating pipe adjacent the exhaust end thereof forcibly and continuously exhausts off the gaseous content of the ventilating pipe to atmosphere at a location remote from the stacks.