Abstract: The invention disclosed herein provides a subsonic wind tunnel capable for accurately maintaining a desired Mach number, pressure and temperature for use in aerothermal testing of materials. The invention allows the Mach number to be precisely controlled in the test section of the wind tunnel by employing a restricted outlet acting as a sonic throat for the wind tunnel. In the preferred embodiment, the restricted outlet is constructed to be variable in cross sectional area allowing a range of Mach numbers to be tested. The variable outlet is varied during the operation of the wind tunnel so that an actual trajectory with changing Mach numbers, pressure, and temperature is simulated.

Abstract: A method for identifying memory modifications includes designating a first portion of a first memory as read-only. An abort condition is identified responsive to receiving a write instruction having a target address within the first portion. In response to the abort condition, a second portion of the first memory including at least the target address is flagged as being modified. The write instruction is executed.

Abstract: A voice bridge for a telephone relay for the hearing impaired is constructed so as to pass voice data to and/or from a user who is capable of either speaking or hearing voice. The voice bridge is capable of passing voice communication between a pair of telephone lines while excluding data carrier TDD signals from passage. Several methods are possible to achieve TDD signal exclusion. A privacy option is also included to exclude the relay station operator from overhearing parts of conversation when the operator's assistance is not required.

Abstract: An ozone generating unit comprises a number of dielectric tube and electrode assemblies bundled together in confronting contacting relationship, each dielectric tube and electrode assembly preferably comprising a number of concentrically related and spaced dielectric tubes. The ends of the dielectric tubes into which gas is to be ozonized is to flow terminate at different points located progressively axially inwardly thereof proceeding from the outermost to the innermost dielectric tube. An outer cylindrical conductive electrode is rigidly frictionally fitted over the outermost of the dielectric tubes. Supported on the inner surface of each dielectric tube is an inner cylindrical electrode made of a sheet of resilient flexible conductive mesh material initially deformed into a given curvature different from that of the cylindrical inner surface of the associated dielectric tube so that the inner cylindrical electrode expands into contact with the cylindrical inner surface of the associated dielectric tube.