Abstract: A waveguide carbon dioxide (CO.sub.2) laser includes a six-sided laser block comprising first and second triangular end sections and a rectangular insert block. The two triangular end sections include a waveguide grid comprising two sets of parallel waveguide channels intersecting at right angles and optically coupled by strip mirrors disposed along the edges of the triangular sections. The rectangular insert block also includes a set of parallel waveguide channels which are congruent with and aligned parallel to the waveguide channels of the two triangular end sections, thereby extending the cavity length of a multiply folded waveguide laser without a corresponding increase in the number of optical folds, the number of folding mirrors, or the value of distributed loss.

Abstract: The present invention describes a water retardant material produced by a mixture of earthen clay and 15% to 25% by weight of recycled paper pulp sludge. Paper pulp sludge is incinerated in a rotary kiln, typically a rotary cement kiln asphalt dryer, or fluidized bed incinerator. Paper pulp sludge is fed continuously into said rotary kiln while temperature are maintained in the range of approximately 800.degree. to 3500.degree. F. During incineration, mixing catalysts (typically casein or soy protein) and wood pulp fibers are burned while moisture is evaporated. The resulting incinerated product consists essentially of carbonate particles which are collected for subsequent use. Use of this material as a water retardant covering for landfills is described.

Abstract: This invention provides a method and apparatus for recycling paper pulp sludge. Paper pulp sludge is incinerated in a rotary kiln, typically a rotary cement kiln, asphalt dryer, or fluidized bed incinerator. Paper pulp sludge is fed continuously into said rotary kiln while temperatures are maintained in the range of approximately 800.degree. to 3500.degree. F. During incineration, mixing catalysts (typicaly casein or soy protein) and wood pulp fibers are burned, while moisture is evaporated. The resulting incinerated product consists essentially of carbonate particles which are collected for subsequent use. Typically, but not exclusively, later use of the resulting product could be as mineral filler binding agents in the manufacture of construction products such as concrete, asphalt and others; or in gravel-based construction operations; or in earthen-fill constructions operations; or in other ways.

Abstract: Low density, high temperature and aluminum-rich intermetallic alloys displaying excellent elevated temperature properties, including oxidation resistance, are disclosed. Based on the aluminum/titanium system, specifically modifications of Al.sub.3 Ti compositions, useful alloys are derived from changes in crystal structure and properties effected by selected-site substitution alloying with manganese and/or chromium, and, where used, vanadium, or equivalent site-substituting alloying elements.

Abstract: An improved method and apparatus for underwater communication, the apparatus comprising two dipoles disposed in a common body of water, both dipoles including a pair of separated electrodes, a transmitter connected to one dipole, a receiver connected to the other dipole and a nonconducting hose or tube extending between one of the electrodes of a first dipole and one of the electrodes of the second dipole.

Abstract: A moisture protective housing for a sound transducer located inside the face mask of a diver which face mask is vented to a breathing apparatus, such as a scuba tank with regulator, to maintain the air breathed by the diver at substantially the same pressure as the water surrounding the diver. The housing includes a deformable portion having pin prick perforations or pores therethrough to make that portion porous when formed. The number of perforations or pores, as well as their size, are selected such that the porous portion becomes permeable to air and/or water only if the pressure differential across it exceeds a preselected value.

Abstract: A switch which is activated by a voice signal which is higher than the normal voice signal but which is sustained by the normal voice signal and which is disabled by the absence of any voice signal much below the normal voice signal for a predetermined period of time. The voice actuated switch is particularly useful inside a high noise environment, such as the mask of a scuba diver or aviator in which the breathing noise is of the same order of magnitude as ordinary speech noise. The voice activated switch includes a HI comparator which provides an activation signal only when a word is spoken above a certain HI loudness level, and a LO comparator which provides a sustaining level when exposed to a signal from noise or voice at a normal level for a selected time interval.

Abstract: A pulse width modulated power supply contains an inverter circuit which includes a plurality of transistors connected to a drive transformer. The transistors are caused to conduct alternatively to provide a switching waveform at an output, which waveform is filtered to provide a regulated DC output voltage.The supply includes means for preventing switch-through of the transistors while providing regulation of the output voltage to keep the same constant over a wide range of operating conditions.Other means provide an efficient drive for the inverter as well as the capability of operating the supply at either of two input voltage levels.