Abstract: A fishhook is described which disintegrates upon standing for prolonged periods of time in an aqueous environment such as within biological tissue. In one embodiment, the fishhook comprises a biodegradable polymeric hook-shaped structure with at least one metal tip affixed thereto providing a sharp piercing element. Upon exposure to the chemical environment of the fish's tissue the polymer biodegrades. In another embodiment, a substantially insoluble or non-biodegradable body portion of the hook has a separable point and barb portion affixed to the insoluble portion by means of a biodegradable adhesive. When the fishhook penetrates the fish's tissue, the solvents and/or enzymes present in the tissue environment causes the adhesive to release the barb and/or the point of the fishhook and the fish may shed the disintegrated fragments. In yet another embodiment, the entire fishhook is fabricated from a biodegradable polymer such as polylactide or polyglycolide or a copolymer thereof.

Abstract: A hydraulic control system for a vacuum sweeper truck including a hydraulic pump coupled to the truck's engine, a reservoir of hydraulic fluid, a hydraulic fan motor, a hopper actuator, and a valve assembly having three operative positions. In a first position the hopper actuator is deactivated and full power goes to the vacuum fan motor. In a second position the hydraulic fluid is diverted to the hopper actuator to raise the hopper and the vacuum fan motor is run at a reduced speed by hydraulic fluid returning to the reservoir. In a third position, the hydraulic fluid is again diverted to the hopper actuator to drive the hopper in a second direction, and again the fan motor is run at a reduced power level. A compensator is coupled to the hydraulic pump and is responsive to a cut-off setting and to the hydraulic pressure produced by the pump.