Abstract: The present invention relates to a new kinetic-energy projectile. The projectile of the invention comprises a piercing head consisting of:a head penetrating meansa main penetrating meansand a spacing means located between the head penetrating means and the main penetrating means.The projectile of the invention is used to pierce light, heavy and strongly sloping armor.

Abstract: Apparatus is described for releasing a storage container from an inflatable upport such as a parachute, comprising a container for holding the inflatable support, an attachment mechanism extending through the container, linear slide means engaging the attachment mechanism and a storage container when tension is applied to the attachment mechanism, and means for holding the attachment mechanism in tension until the inflatable support is inflated, whereby the storage container remains fixed to the inflatable support until tension on said attachment component is relieved.

Abstract: The primer comprises a conductive pyrotechnical priming composition 3, placed in contact with the useful pyrotechnical charge 2 of the primer and two electrodes 6 and 7 arranged in electrical contact with the conductive pyrotechnical composition 3.The two electrodes 6 and 7 are connected to a stable electric resistor 10, connected in parallel to the conductive pyrotechnical composition 3.

Abstract: A new piezoelectric transducer incorporated with a mechanical amplifier is described. The transducer comprises a rigid base plate; two lateral plates whose lower edge is connected to the plate by a thin portion; a stack of piezoelectric elements having alternate electrodes; a horn formed of a flexible elastic diaphragm which connects together the upper edges of the two plates; an enclosure and a sealing skin which is acoustically transparent. The tranducer is capable of emitting or receiving high power acoustic waves of very low frequencies including for instance, a few Hertz to 500 Hz.

Abstract: The invention relates to spiropyran compounds. They have the general formula (I): ##STR1## in which: X represents the CH.sub.2 group or a sulfur atom; R.sub.1 and R.sub.2 represent electron donor and/or acceptor groups selected for instance from the group NO.sub.2, COC.sub.6 H.sub.5, CN, the halogens, the acyl substituents, alkoxy substituents, the hydrogen atom, the alkyl and mercaptoalkyl groups, the ethers of the formula CH.sub.2 OR, thioethers of the formula CH.sub.2 SR and amines of the formula CH.sub.2 NR.sub.2 in which R represents an alkyl group; R.sub.3 is a linear or branched alkyl group, having 1 to 18 carbon atoms, or an arylalkyl or alkenyl group.--R.sub.4,R.sub.5,R.sub.6,R.sub.7,R.sub.8 and R.sub.9 have one of the meanings indicated for R.sub.3 or represent, two by two, with the group in ortho position, a --(CH.sub.2).sub.n -- group in which n is a number between 5 and 10.R.sub.10 represents a hydrogen atom if X=S and if X=CH.sub.

Abstract: A rivet apparatus is provided for securing together a first element to a second element made of solid metal. The apparatus comprises a support 3 which is common to the first element and to a hollow charge 4. A metal rivet or nail 5 embedded in the charge of the hollow charge, in the axis of a liner 6 of the hollow charge 4. The support 3 has a surface 7 intended to be applied against a second hard metal element 2 and approximately centered on the focal point F of the hollow charge 4. Upon detonation of the charge, the metal rivet or nail 5 enters the second element 2 thereby binding first and second elements together.

Abstract: A piezoelectric resonator comprises a crystal having an outer peripheral portion connected to a central portion by an intermediate zone which is short in the radial direction, is hollowed out over its major part and has at least two connector bridges between the outer and central portions. Electrodes are arranged facing one of the main portions of the crystal which then forms the vibrating portion of the resonator. The non-vibrating main portion serves as a support for the crystal. The surfaces of the connector bridges are continuous with the corresponding surfaces of the vibrating portion.

Abstract: An automatic two wavelength photoelasticimeter comprising, in succession, a light source for emitting light having at least two wavelengths, .lambda..sub.1 and .lambda..sub.2 ; a polarizer rotating at constant speed, an orientable quarter-wave plate of orientation .beta. with respect to a reference axis; a model to be analyzed exhibiting double-refraction and having a fast axis which forms an angle .theta. with respect to the reference axis and which provides a phase shift .phi. (which parameters .theta. and .phi. are to be measured) and three photodetectors 5, 6, and 7 preceded by analyzers 10, 11 and 12 respectively. The photodetectors 6 and 7 are preceded by filters 8 and 9 of wavelengths .lambda..sub.1 and .lambda..sub.2 respectively. The difference between the phases of the signals of the frequency 2.omega.

Abstract: Piezoelectric transducers and antennas comprising a plurality of identical transducers arranged coaxially, each transducer comprising a ring and a plurality of piezoelectric motor elements arranged radially against the inner wall of the ring. The rings form an envelope which is closed by two covers and the envelope encloses an axial cylindrical channel containing a piston. The inside of the envelope contains a solid material which is elastomeric or rigid and is separated from the inner walls of the envelope by a small clearance which communicates with the end of the cylinder. An application is the construction of acoustic antennas intended to be immersed to great depths.