The Aggregates & Recycling Information Network

Glossary: U

  • UBR

    abbr. uniform business rate.

  • Ultrabasic Rock

    Igneous rock containing less than 45% silica.

  • Ultrasonic Test

    A test for comparing the strengths of concretes as described in British Standard 1881: Part 203.

  • Unbound Aggregate

    Drystone which is not mixed with cement or bitumen.

  • Underflow

    That proportion of the feed which has passed through the apertures in a screen deck.

  • Undersize

    Material in a product of a size smaller than the lower nominal size; may be expressed as a percentage of the product.

  • Uni-flow

    In washers, the mineral being treated and the wash water flow in the same direction and, in screening, the direction of vibration of an inclined screen is such as to assist the passage of mineral along the screen.

  • Universal Coupling

    Couplings used on the ends of the propeller shaft of motor vehicles to allow for the movement of the rear axle relative to the gear box. It consists of a modern version of Hooke’s coupling in which two yokes set at 90° to each other are joined by a trunnion block.

  • Universal Motor

    A fractional-horsepower motor which can work on both direct current and single-phase alternating current.

  • Upthrow

    The amount, measured vertically, of upward displacement of beds caused by a fault.