Abstract: A burn-in resilient integrated circuit is provided. The burn-in resilient integrated circuit includes an inverter chain and a plurality of inverter circuits on the inverter chain. The burn-in resilient integrated circuit also includes a loop providing an electrical connection from an output of the inverter chain to an input of the inverter chain. The loop is selectable in accordance with a burn-in operation.

Abstract: A portable rebound net using a tension adjustable elastic net material lashed to a frame structure is provided. Adjusting the tension of the elastic netting material allows the user to alter the return speed of a ball hit against the rebound net.

Abstract: A system and support means for creating lateral and compressive forces in and for supporting mine roofs, and particularly in coal mines and the like, where the roofs frequently include, at least in part, layers of rock and shale in overlying strata, and are notoriously weak in tensile and shear strength. A plurality of individual support means or members are inserted vertically into holes bored in the mine roof, and each includes expansion means, operable by bolt means available below the mine roof, to activate the expansion means to thereby create lateral and compressive support forces within the various strata layers, thereby so strengthening the roof structure as to prevent collapse of a mine roof or portions thereof.

Abstract: Support means and system for supporting mine roofs, and particularly those areas of mine roofs between ribs of pillars in coal mines. Coal mine roofs frequently consist, at least in part, of shale in overlying strata, and are notoriously weak in tensile and shear strength. Heretofore, mine roof bolts for strengthening installation systems have been known. Bolts of different types, and different installation systems and patterns have been used. Various drawbacks have existed.The present invention teaches a roof bolt manufacture, and an improved installation use system and pattern. The bolts include a pair of coactive elongated steel members. One member is of a general U-shaped configuration and has edges of a generally undulating or stepped wavilinear configuration, with the formed apex portions slightly inturned.