Abstract: A process and apparatus for controlling the cleaning of a grille for filtering cooling air of a radiator particularly of engines, in which the cooling air is forced with the aid of a ventilation system and in which the cleaning is effected by blowing with the aid of at least jet cleaner assembly sweeping tangentially the surface of the grille. The jet cleaner assembly is controlled as a function of a parameter connected to the regime or the flow of the ventilation system and/or each time or the same time as the regime or flow falls to or below a predetermined level.

Abstract: A compound of formula (I) or a salt thereof, or a solvate thereof, wherein either (i) Ra represents a group R.sub.5 which is hydrogen, alkyl or optionally substituted aryl and R.sub.5 represents a moiety of formula (a); wherein X represents a hydroxy or an alkoxy group wherein the alkyl group may be substituted or unsubstituted or X represents a group NR.sub.s R.sub.t wherein R.sub.s and R.sub.t each independently represent hydrogen, alkyl, substituted alkyl, optionally substituted alkenyl, optionally substituted aryl, optionally substituted arylalkyl, an optionally substituted heterocyclic group or an optionally substituted heterocyclylalkyl group, or R.sub.s and R.sub.t together may form a heterocyclic group; R.sub.1 represents an alkyl or a substituted or unsubstituted aryl group; and R.sub.2, R.sub.3 and R.sub.4 each independently represent hydrogen, alkyl, aryl or substituted aryl or (ii) R.sub.a represents a moiety of the above defined formula (a) and R.sub.b represents the above defined R.sub.5 ; R.

Abstract: A package for a temperature sensitive optical component (20) includes inner (14) and outer (12) containers of low thermal conductivity plastics material, a foam insulation (18) being situated between the two containers. Within the inner container (14) are a thermally conductive plate to which the component (20), a temperature sensitive resistor, and a resistive heating element are affixed. A temperature compensating circuit (16) is located outside the inner container. The temperature sensitive resistor is part of a Wheatstone bridge at the input of the circuit (16), whereby the circuit compensates for variations in operating voltage. The output transistor of the circuit regulates the current through the resistive heating element in response to variations in the resistance of the temperature sensitive resistor. This transistor extends into the inner container (14) and is in contact with the thermally conductive plate, whereby heat from the transistor is dissipated into the plate.

Abstract: A method for forming a substantially flat planar lightwave optical circuit which has a substantially flat planar silica substrate and a sintered glassy lightguiding layer over the silica substrate. The structure is given a post treatment at an elevated temperature for a time sufficient to flatten said structure and overcome any distortion caused by the difference in the coefficient of thermal expansion of the substrate and any glassy layers formed over the substrate. Alternatively, the silica substrate may be heated and presagged to a predetermined degree to compensate for distortion or warpage which will occur in later processing.

Abstract: A thrust reverser is disclosed for a turbojet engine having a central axis and an exhaust nozzle wherein the thrust reverser has a plurality of deflectors pivotally attached to the turbojet engine so as to pivot about axes extending generally traverse to the central axis between a forward thrust position, wherein the plurality of deflectors form a downstream end of the exhaust nozzle, and a reverse thrust position wherein the deflectors deflect gases emanating from the engine to generate a reverse thrust. Each of the movable deflectors has a downstream trailing edge located such that all of the trailing edges of the deflectors lie in a common plane extending substantially transverse to the central axis.