Abstract: A process for the predictive determination in the pre-critical range of the load at rupture of a structure, comprising subjecting the structure to a stress of the same type as the load and for a time according to a predetermined law, whilst recording the acoustical activity generated by the resulting damage, until a predetermined stress threshold is reached. A correlation is maintained between the registered acoustic emission and the relation ##EQU1## in which: ##EQU2## is the variation of acoustic energy generated by the damage, t is time,t.sub.r is the instant of rupture, .DELTA., .alpha., C, .lambda. and .phi. are coefficients, so as to predetermine the value of prediction of the load at rupture from the above law connecting time and load.

Abstract: The invention provides a device for delivering an indication about the mass per unit volume of the contents of an elementary volume, comprising a directional X or gamma radiation source and a directional photoelectronic photon detector, and wherein said source and/or said detector are mounted for rotation on a common support, about an axis orthogonal to the plane defined by the axis of the radiation beam emitted by said source and by the axis of the reception channel of said detector, and means are provided for moving said common support in a direction orthogonal to the axis of rotation of said source and/or of said detector.

Abstract: This invention concerns a device for the non-destructive inspection of a part (6) by means of optical holography. This device includes a source (2) emitting a laser beam and a holographic camera (4) placed at a certain distance from the source (2) and close to the part to be inspected (6); the laser beam is transmitted from the source (2) to the camera (4) by means of a beam of sequenced optical fibers (8) suitable for transmitting a high-powered laser beam, while maintaining the coherence of space and time of this laser beam. The device is suitable for interferometry nondestructive inspection applications.