Abstract: A continuous stream binary array ink jet print head comprising: an elongate cavity for containing the ink; an array of nozzle orifices (37) formed so as to extend through a wall of said cavity for passing ink from the cavity to form jets, said nozzle orifices (37) extending along the length of said cavity, said cavity being divided up along its length by at least one internal wall (33) thereby to create a plurality of sub-cavities (35) substantially acoustically isolated from one another, said dividing up of the cavity to form sub-cavities (35) correspondingly dividing up said array of nozzle orifices (37) between the sub-cavities (35) such that each sub-cavity communicates with one or more of the nozzle orifices (37) of the array; one or more actuator (39) means associated with each said sub-cavity for cyclically varying the dimensions of the sub-cavity thereby to cause the or each jet emanating from the nozzle orifice(s) of that sub-cavity to break up into ink droplets at a predetermined distance therefrom;

Abstract: A continuous stream ink jet print head has a droplet generator with an elongate cavity for containing the ink, and nozzle orifices in a wall of the cavity for passing ink from the cavity to form jets. The nozzle orifices are disposed at spaced positions along the length of the cavity. An actuator for vibrating the ink in the cavity is provided such that each jet breaks up into ink droplets at the same predetermined distance from the wall of the cavity. The actuator is disposed on the opposite side of the cavity to the wall, includes a vibrator which is divided up along the length of the cavity at least partially into at least two parts, and includes a backing member disposed further from the cavity than the vibrator and secured to and bridging the parts into which the vibrator is at least partially divided. The vibrator is interposed in line between the backing member and the cavity.

Abstract: A variable gain optical amplifier, in which homogeneous gain broadening is dominant, has first and second fixed gain rare-earth doped optical waveguide amplifiers (21, 23) optically in series together with an intervening variable attenuation optical attenuator (22). This arrangement circumvents the problem of gain tilt encountered when operating such amplifiers under variable gain conditions. An alternative form of the module has variable gain waveguide amplifiers, but these are co-regulated so that the aggregate of their gain at a wavelength within the gain spectrum is maintained constant. A further alternative form of module is employed in a concatenation of such modules. In such a concatenation, the gain of individual modules is allowed to vary, but the aggregate of the gain, at a wavelength within the gain spectrum, of all the waveguide amplifiers of all the modules of the concatenation is maintained constant.

Abstract: A Web browser (210) is configured to run in a middle compartment (206) of a Compartmented Mode Workstation (CMW) (200). The operation of the Web browser (210) is prevented from accessing or damaging other compartments of the CMW machine (200) as a result of mandatory access control (MAC), which is configured appropriately. The Web browser (210) communicates with Web servers (252) attached to the internet (240), the Internet being connected to an outside compartment of the CMW machine (210), via a trusted outside process (TPO) (214). TPO (214) has the privileges required to override MAC. The Web browser (210) communicates with a display server (232), which is attached to an inside compartment (204) of the CMW machine (210), via a trusted inside process (TPI) (204). TPI also has privileges to override MAC. The Web browser (210) can request and receive Web pages incorporating mobile code, and can process the mobile code safely within the middle compartment (206).

Abstract: A variable gain optical amplifier, in which homogeneous gain broadening is dominant, has first and second fixed gain rare-earth doped optical waveguide amplifiers (21, 23) optically in series together with an intervening variable attenuation optical attenuator (22). This arrangement circumvents the problem of gain tilt encountered when operating such amplifiers under variable gain conditions. An alternative form of the module has variable gain waveguide amplifiers, but these are co-regulated so that the aggregate of their gain at a wavelength within the gain spectrum is maintained constant. A further alternative form of module is employed in a concatenation of such modules. In such a concatenation, the gain of individual modules is allowed to vary, but the aggregate of the gain, at wavelength within the gain spectrum, of all the waveguide amplifiers of all the modules of the concatenation is maintained constant.

Abstract: A droplet generator for a continuous stream ink jet print head has a cavity for containing ink, and nozzle orifices passing ink from the cavity to form jets. An actuator means vibrates the ink in the cavity such that each jet breaks up into ink droplets. The actuator means is disposed on the opposite side of the cavity to the nozzle orifices, and a surrounding wall of the cavity extends between the actuator means and nozzle orifices for containing the ink therebetween. The surrounding wall has inner and outer constituent wall. The resistive component of the wave impedance of the outer wall passively damps vibration of the inner wall by dissipating its vibration; the reactive component of the wave impedance of the outer wall actively restrains vibration of the inner wall, ensuring that each jet breaks up into ink droplets at the same predetermined distance from its respective nozzle orifice.

Abstract: In an optical transmission system employing optical amplifiers a method of regulating the gain of such an amplifier uses a non-linear control system whose non-linearity of operation is provided at least in part by the enabling/disabling of a portion of the control system by the operation of a transient magnitude threshold sensor.

Abstract: A droplet generator for a continuous stream ink jet print head has a cavity (3, 23) for containing the ink; nozzle orifices (17, 27) in a wall (9) of the cavity (3, 23) for passing the ink from the cavity (3, 23) to form jets; and first (11, 21) and a second (13, 25) actuator device for establishing in combined operation a travelling wave. The travelling wave travels from the fist actuator device (11, 21) through the ink to the second actuator device (13, 25) and passes in a direction substantially parallel to the wall (9) containing the nozzle orifices (17, 27).

Abstract: An optically amplifying waveguide guides both the LP.sub.01 and the LP.sub.02 mode. Its erbium distribution profile is preferentially matched with the modal field distribution of the LP.sub.02 mode. The waveguide is provided with long period perturbations of a pitch and strength that resonantly couples signal power of different wavelengths from propagation in the LP.sub.01 mode to propagation in the LP.sub.02 mode and back again to propagation in the LP.sub.01 mode whereby the longitudinal distribution of gain along the waveguide at one wavelength is longitudinally displaced with respect to that at least one other wavelength.

Abstract: A patient subjected to laryngectomy is provided surgically with a fistula intended to serve as a pseudo-glottis, and a tracheostome, these two tracts being sited in the midline region of the neck surface. A laryngeal prosthesis for the patient is of generally symmetrical form comprising a hollowed main body with two external tubes to respectively engage the surgically-formed tracts, the fistular tube being sufficiently short to avoid inhibiting the pseudo-glottis function. The prosthesis body is apertured to provide a valve function communicating the tracheal tube with atmosphere for respiration, or with the fistular tube for phonation. This function can be effected by a normally-open flap valve closable by a first high pressure in the body, and a normally-closed blow-out valve may then be appropriate to open at second higher pressure to remove secretions, together with a further normally-open valve to close the fistular tube at the higher pressure.

Abstract: A patient subjected to laryngectomy is provided surgically with a fistula intended to serve as a pseudo-glottis, and a tracheostome, these two tracts being sited in the midline region of the neck surface. A laryngeal prosthesis for the patient is of generally symmetrical form comprising a hollowed main body with two external tubes to respectively engage the surgically formed tracts, the fistular tube being sufficiently short to avoid inhibiting the psuedo-glottis function. The prosthesis body is apertured to provide a valve function communicating the tracheal tube with atmosphere for respiration, or with the fistular tube for phonation. This function can be effected by a normally open flap valve closable by a first high pressure in the body, and a normally closed blow-out valve may then be appropriate to open at second higher pressure to remove secretions, together with a further normally open valve to close the fistular tube at the higher pressure.