Abstract: The present invention is directed to isotopically enriched optical materials and methods of producing the same. The optical materials provide high isotopic purity silica, calcium, zinc, gallium and germanium materials with increased resistance to optical damage which can be used alone or in combination with other means of preventing damage to decrease lens degradation caused by energy-induced compaction during use.

Abstract: A core-chuck device having reusable parts as well as replaceable interchangeable-fins for use within the field of large-scale paper, film, or foil manufacturing. The reusable core-chuck device provides a versatile and lightweight core-chuck of plastic material, where the outermost diameter of the core-chuck can be modified by replacement of radially spaced interchangeable-fins of varying sizes on the core-chuck. The interchangeable-fins are matingly securable within the central-hub of the core-chuck device. The inner-core of the central-hub contains a metallic element that enables mechanical handling of a paper-roll having one core-chuck device inserted into each end of the paper-roll core. An optional end-cap is also included which secures the interchangeable-fins from longitudinal movement with respect to one another. The core-chuck device results in a cost-effective alternative to prior-art devices.

Abstract: The novel weight-balancing device of the present invention is adapted for use in the improved backpack of the present invention. The device comprises a set of two elongated tubes, disposed in telescoping relation to each other with a spring-loaded push button carried by the inner tube adjustably releasably locking the tubes together so that they can have various desired combined lengths. One of the tubes has a slip resistant backpack shoulder strap connector attached at its front end and the other of the tubes has a backpack rear frame connector pivotally secured to its rear end.The improved backpack utilizes a pair of the described novel devices, connected to opposite sides of the backpack rear frame and projecting forwardly to engage the two backpack shoulder straps. Thus, the two devices are disposed on opposite sides of the backpacker.