Abstract: An aeroponic grow tower is provided. The tower includes a modular wall system located between a cover and a base. The wall system includes a plurality of individual flat, four-sided wall panels. The identical wall panels are removably connected along their side edges into one or more levels having a polygonal shape. Levels are aligned and stack atop the base and each other. The wall panels have openings defining grow sites configured to support plants such that foliage extends to the outside and roots hang inside the tower. A pump delivers nutrient solution from the base to a high-rotational speed spray nozzle which aerosolizes the solution. The spray also impacts the interior surface further aerosolizing the solution. Channels direct the solution running down the interior surface to the grow sites which include secondary reservoirs to provide a further source of nutrient solution. A ventilation system and seedling covers are also provided.

Abstract: A nut-and-bolt fastener is provided. The nut and bolt are configured with a plurality of interlocking teeth that provide unidirectional travel of the nut with respect to the bolt. In particular, the configuration of the teeth arrest separation of the nut from the bolt while permitting the nut to move toward the head of the bolt into a fastened engagement. The teeth are non-helical and arranged concentrically around the longitudinal axis in evenly-spaced steps or segments along the longitudinal axis and around the shaft of the bolt and bore of the nut. Integral winged washers are provided on the bolt head as well as on the nut. Variations with different rake angles of the teeth as well as an expandable nut are also provided.