Abstract: A hot-water heating system for use by submarines, divers and the like in an underwater environment includes a heating-medium circuit and a hot-water circuit. The heating-medium circuit includes an electric-motor-driven compressor in a water-tight submersible housing for compressing a heating-medium fluid. The heating-medium circuit also includes a condenser heat exchanger, a throttle valve, and an evaporator heat exchanger connected in series between a discharge outlet and a suction inlet of the compressor. The evaporator heat exchanger can make thermal contact with water surrounding the water-tight housing to absorb heat from the water and the condenser heat exchanger make thermal contact with the water in the hot water circuit to transfer heat to the water.

Abstract: A modular system for performing optical spectroscopy measurements comprising enclosed modules with ports through which optical beams may pass into and out of the modules. The modules may be joined together with the ports aligned and are interchangeable in the sense that the focal point of the optical beam directed out of any output port has the same location relative to the output port.

Abstract: A sample chamber for an optical spectrometer comprising means for selecting one of two modes of operation: a transmission mode or a reflection mode. The mode-selecting means comprise optical elements for switching the path of the optical beam passing through the sample chamber so that the beam either passes through a sample or is incident upon and reflects off of a surface of a sample. Coupled to the path-selecting means are means for moving a sample to the position and orientation relative to the optical beam which is appropriate to the mode of operation selected.