Abstract: A method is shown for testing a magnetic disk to be used in a disk drive. The method includes the steps of measuring a height profile of an outer radial edge of the disk, using the profile to determine a slope value for each of a pair of radial segments of the disk, calculating a difference value between the slope values of the pair, comparing the difference value to a preselected threshold difference value and indicating when the difference value is equal to or less than the threshold difference value. The threshold value indicates an outer most diameter of the disk where fly height operation for a head is still stable.

Abstract: A steam desuperheater comprising a liquid spray tube assembly positioned in a steam line and including a plurality of liquid outlet openings supplying liquid to plural spray nozzles, and a hollow piston plug axially movable therein upwardly from a lower valve seat to progressively open said outlet openings.

Abstract: The disclosure is related to a sound level meter including unique features for measuring, storing and displaying a maximum sound level generated by a passing motor vehicle or the like. The meter operates as an ordinary sound level meter until a predetermined threshold noise level is reached, at which time a novel circuit continuously detects the incoming sound level and electrically stores the maximum value detected. A comparison means compares the incoming sound level with the maximum stored level. When the incoming sound level decreases by a predetermined amount below the maximum stored value, a circuit is energized to lock the maximum value detected in a memory device. Additional means are provided to visually display the stored value.