Abstract: Disclosed is an apparatus and method for producing frac sand, in order to meet size, sphericity and roundness standards, from a feedstock such as natural sand. The feedstock is rotated as slurry in a conditioning cell, so that it self abrades to produce frac sand with the required characteristics.

Abstract: Disclosed is an apparatus and method for producing frac sand, in order to meet size, sphericity and roundness standards, from a feedstock such as natural sand. The feedstock is rotated as slurry in a conditioning cell, so that it self abrades to produce frac sand with the required characteristics.

Abstract: An inflatable plug assembly suitable for use in the plugging of boreholes. The plug assembly having quick and slow inflation working modes selectable by the operator. The slow inflation working mode is obtained by orientation of the plug assembly such that the gas phase of the expandable working fluid is released on actuation by the operator. The quick inflation working mode is obtained by orientation of the plug assembly such that liquid phase expandable working fluid is released on actuation by the operator.

Abstract: A computing system with a SCSI controller includes SCSI transmission mode selection apparatus and method to switch the transmission line drivers between transmitting in SCSI 1, SCSI 2 or another mode. The controller selects a maximum data transmission rate compatible with each peripheral device connected to the controller. A user-defined option code is decoded by the controller to provide the user with control over transmission mode options for the drivers in the controller. Based on the data transmission rate and the selected option, the controller selects the SCSI transmission mode to use for each driver type, acknowledge line or data lines.