Abstract: A slurry feeding assembly (A) feeds a mixture of water and rubber pellets to a comminuting region defined between a rotor (74) and a stator (66). As an electric rotor motor (70) rotates the rotor relative to the stator, a power monitor (114) monitors of a control circuit (D) the amount of electrical power drawn thereby. The control circuit controls a pressure regulator (C) to increase and decrease the pressure between the rotor and stator in such a manner that the power drawn by the electric rotor motor remains substantially constant. The control circuit further initiates operation of various components of the comminuting apparatus in a preselected order. Specifically, the control circuit first starts the feed of water or other fluid to the rotor and stator. Thereafter, the electric rotor motor is started, followed by enabling of the pressure regulator assembly.

Abstract: A pneumatic tire having a ground-engaging tread portion. The tread portion has at least two circumferentially extending grooves, each groove having a pair of oppositely disposed sidewalls. One groove sidewall having a first portion extending radially outward in a substantially vertical direction from the base of the groove to a first point spaced a distance from the bottom of the groove a distance no greater than about one-half of the groove depth and a second portion extending from the first point radially outward to the tread surface at an inclined angle. The second groove sidewall extending from the base of the groove to the tread surface at an inclined angle. The included angle between the second portion of the first groove sidewall and the second sidewall being at least thirty degrees (30.degree.).