Abstract: An abrasion controlled caster wheel is described. When a sideways force is applied to a rear of a grocery shopping or material cart either during normal operation or when gathered in the parking lot, the caster wheel, at the rear position of the cart, will redirect its direction of travel or change its mount rigidity rather than scraping sideways across the wheel circumference.

Abstract: Method and apparatus are provided for treating (e.g., recycling) polystyrene foam scrap particulate in a manner which increases the density of the polystyrene while minimizing an amount of heat required to convert the polystyrene into densified solid polystyrene plastic (e.g., polystyrene flakes), thereby avoiding noticeable polymer degradation. The invention involves first heating polystyrene particulates to a semi-molten state in a heating zone so that polystyrene particulates coalesce. Pressure is then applied in a pressure zone to the polystyrene while the polystyrene is coalescing. The pressure is applied by a pressure mechanism which crushes the heated and softened polystyrene, and which preferably maintains the pressure on the polystyrene until the polystyrene cools below the softening temperature of the polystyrene. The pressure mechanism squeezes essentially all gases (entrained air and expansion gases) from the polystyrene, and thus precludes, e.g.