Abstract: The transit time of acoustic waves between a generator and a receiver positioned across a fluid chamber is determined by generating acoustic waves using a self-purging pneumatic sound generator, a transducer adjacent the outlet of the sound generator, and a receiving transducer positioned away from the sound generator outlet so that the acoustic waves received by the receiving transducer pass through a portion of the fluid. The electrical signals generated by the transmitting transducer and the receiving transducer are processed to obtain the impulse response of these electrical signals, and the point of maximum value is determined. This point of maximum value corresponds to the arrival time of the acoustic waves at the receiving location. The transit time determination may be used to calculate the fluid temperature or other parameters.

Abstract: The average volumetric velocity U.sub.m of a fluid flowing within a large industrial flue stack is determined by a combination of measurement and calculation techniques. The temperature, velocity head and static pressure of the stack fluid are measured at two points within the bounded path of the flue stack. The flight time of a random acoustic noise wave is measured in both the upstream and downstream directions. The path average velocity U.sub.p is determined from the measured values of the upstream and downstream flight times. The fluid velocity is determined using the measured values of the flight times, the fluid temperature, velocity head and static fluid pressure. The determined values of the path average velocity U.sub.p and the fluid velocities are used to determine the average volumetric velocity U.sub.m. A curve fitting algorithm is employed to determine an approximation of the actual fluid flow distribution across the bounded path, and this approximation is used to calculate U.sub.m.

Abstract: The transit time of acoustic waves between a generator and a receiver positioned across a fluid chamber is determined by generating acoustic waves using a self-purging pneumatic sound generator, a transducer adjacent the outlet of the sound generator, and a receiving transducer positioned away from the sound generator outlet so that the acoustic waves received by the receiving transducer pass through a portion of the fluid. The electrical signals generated by the transmitting transducer and the receiving transducer are processed to obtain the impulse response of these electrical signals, and the point of maximum value is determined. This point of maximum value corresponds to the arrival time of the acoustic waves at the receiving location. The transit time determination may be used to calculate the fluid temperature or other parameters.

Abstract: A method and apparatus of measuring rock-stress uses a tapered sensing plug which is wedged into a conically shaped end portion of a borehole. A rod is used to place the sensing plug in position, to orient the plug relative to its longitudinal axis for sensing stress in a particular direction, and to prestress the sensing plug by causing same to be wedged in the tapered portion of the bore.

Abstract: An anchor device for securing a rock bolt in a borehole of predetermined diameter includes an elongated plastic cartridge having a first insertable end and a second end, a side wall extending between the ends, and stiffening ribs integrally formed in the sidewall for stiffening the cartridge to permit insertion thereof into the borehole.

Abstract: Anchor device for securing a rock bolt in a borehole, comprising an elongated cage having a perforated elongated wall confining an elongated chamber containing a bonding means for bonding the rock bolt within the borehole, the cage having a trailing end adapted to mount the anchor device onto the leading end of a rock bolt for insertion into the borehole.