Abstract: A shutter assembly comprising a first planar member and a second planar member opposed from one another and forming a sleeve having a cavity therebetween, the sleeve having a pair of side rails adjacent the cavity along sides of the sleeve. A first shutter member having a first end is disposed in the cavity and slidingly disposed along one of the side rails, and a second shutter member having a second end is disposed in the cavity and slidingly disposed along the other side rail. The first end is opposed to the second end and is configured to be selectively advanced towards, and retracted from, the second end so as to define an aperture therebetween having a first shape when disposed in a first position, and wherein the aperture has a second larger shape when the first end is disposed in a second position. The first shutter member and the second shutter member maintain a thermal contact with the side rails and the planar members in all positions.

Abstract: A device operable in a ultra-high vacuum and in a cryogenic environment. The device has bi-stable solenoid motors configured to drive a shutter assembly defining an aperture having a first shape when the motors are each disposed in the respective first position, and wherein the aperture has a second shape when the motors are each disposed in the respective second position. Actuators responsive to the motors are thermally isolated from the cryogenic shutter assembly except when the motors position the shutter assembly to change a shape of the aperture. The device is suitable for use in FLIR and other thermally sensitive devices.

Abstract: A device operable in a ultra-high vacuum and in a cryogenic environment. The device has bi-stable solenoid motors configured to drive a shutter assembly defining an aperture having a first shape when the motors are each disposed in the respective first position, and wherein the aperture has a second shape when the motors are each disposed in the respective second position. Actuators responsive to the motors are thermally isolated from the cryogenic shutter assembly except when the motors position the shutter assembly to change a shape of the aperture. The device is suitable for use in FUR and other thermally sensitive devices.

Abstract: A shutter assembly comprising a first planar member and a second planar member opposed from one another and forming a sleeve having a cavity therebetween, the sleeve having a pair of side rails adjacent the cavity along sides of the sleeve. A first shutter member having a first end is disposed in the cavity and slidingly disposed along one of the side rails, and a second shutter member having a second end is disposed in the cavity and slidingly disposed along the other side rail. The first end is opposed to the second end and is configured to be selectively advanced towards, and retracted from, the second end so as to define an aperture therebetween having a first shape when disposed in a first position, and wherein the aperture has a second larger shape when the first end is disposed in a second position. The first shutter member and the second shutter member maintain a thermal contact with the side rails and the planar members in all positions.

Abstract: According to one embodiment, an optical device includes a variable aperture mechanism configured on a structure having a radiation detector that receives radiation through an aperture of the variable aperture mechanism. The aperture is selectively movable from a first position to a second position in which the aperture has a different size relative to the aperture in the first position. The structure is configured with one or more magnets that function with one or more magnetically permeable members configured on the variable aperture mechanism to hold the variable aperture mechanism in at least one position using a magnetic force between the magnets and magnetically permeable members.

Abstract: According to one embodiment, an optical device includes a variable aperture mechanism configured on a structure having a radiation detector that receives radiation through an aperture of the variable aperture mechanism. The aperture is selectively movable from a first position to a second position in which the aperture has a different size relative to the aperture in the first position. The structure is configured with one or more magnets that function with one or more magnetically permeable members configured on the variable aperture mechanism to hold the variable aperture mechanism in at least one position using a magnetic force between the magnets and magnetically permeable members.

Abstract: A revetment block for use forming an articulating revetment mat. The revetment block has first and second ends and first and second sidewalls. The sidewalls have a first lower vertical surface, first and second upper vertical surfaces, and transition surfaces between the upper and lower vertical surfaces. The sidewalls define interlocks which extend outward from the sidewalls and are either normal to the upper vertical surfaces or angled. The sidewalls also design corner spaces comprising a transition surface and at least on vertical surface for operably communicating with an interlock. The revetment block may also comprise a plurality of ducts extending therethrough as well as a dome extending from the top surface of the revetment block. The revetment block may also comprise at least one aperture extend vertically through the block. The aperture may have tapered walls.

Abstract: A revetment block for use forming an articulating revetment mat. The revetment block has first and second ends and first and second sidewalls. The sidewalls have a first lower vertical surface, first and second upper vertical surfaces, and transition surfaces between the upper and lower vertical surfaces. The sidewalls define interlocks which extend outward from the sidewalls and are either normal to the upper vertical surfaces or angled. The sidewalls also design corner spaces comprising a transition surface and at least on vertical surface for operably communicating with an interlock. The revetment block may also comprise a plurality of ducts extending therethrough as well as a dome extending from the top surface of the revetment block. The revetment block may also comprise at least one aperture extend vertically through the block. The aperture may have tapered walls.

Abstract: A revetment block for use as end blocks with an articulating revetment mat. The revetment mat end blocks having a size of about one and a half times larger than the standard blocks of the revetment mat and are formed of precast concrete. The block preferably has four sidewalls each with a vertical portion and a tapered portion. The sidewalls have a plurality of projections and recesses for interlocking with adjacent revetment blocks, wherein some of the recesses form openings with adjacent blocks. The revetment block also has at least one dome with a pair of openings extending from an upper dome plateau to a lower surface of the block. The revetment block further comprises a pair of openings extending from the lower surface of the block to an upper surface. Extending through parallel sides of the revetment block are a plurality of ducts for cable which interlocks the revetment mat rows.

Abstract: A sensor/support system includes a sensor assembly having a planar radiation detector lying parallel to a reference plane, a readout circuit, and an interconnect joining the radiation detector to the readout circuit. The system further includes a support structure, the support structure having a platform with a first side to which the sensor assembly is affixed and a second side oppositely disposed from the first side. A shim is affixed to the second side of the platform. The shim is made of a shim material different from the detector material and the platform material. The shim reduces the strain in the interconnect when the temperature of the sensor/support system is changed, as compared with the strain in the interconnect in the absence of the stabilization structure.

Abstract: Concrete blocks with an open cell structure extending throughout the block are assembled in substantially parallel columns and rows to from a mat structure capable of articulating over underwater structures. The blocks are assembled by flexible cables that pass through the center of each block through perpendicular apertures, which are located on different horizontal planes to prevent intersection of the cables. A removable abrasive resistant pad is placed on one surface of the blocks to prevent the concrete block from causing damage to the structure. The pad is comprised of a solid base with an opening matching the opening on the block. It also has a plurality of upwardly extending post which serve as a contact point between the pad and the underwater structure and at least one self-locking dowel extending downward, which are inserted into dowel holes on one surface of the block, after the concrete has hardened. The entire pad is one homogeneous material.

Abstract: A lifting and placement device for seabed mats. The device has a frame made of a first and second support beam each of which have a release shaft located adjacent thereto. The release shafts are rotatably engaged to a central actuation shaft that when turned cause the release shafts to rotate thereby removing displaceable support pins from retaining supports. Once the support pins are released from the supports, a seabed mat which is supported below the device is released on all sides of the frame. The device has the ability to connect a plurality of frames in end to end relationship allowing a single rotational force applied to an actuation lever to be transmitted along the conjoined frames.