Abstract: An improved underwater arc-welding apparatus that includes a handheld torch assembly connected to an housing that delivers electrical power, a pressurized shielding gas, and a consumable wire electrode to the site of the weldment. The housing is configured such that the diver/operator, himself, can control such welding parameters as the voltage level of the electrical power, the duration of the flow of the shielding gas, and the delivery rate of the electrode. In addition, the housing is configured to allow the entry of water into the space between its components, and these components, including an electric motor that advances the consumable wire electrode, are sealed individually from the water. Electrical connections between the components are effected using underwater cables and connectors.

Abstract: The invention provides an improved mass spectrometer apparatus, and related method, that characterizes aerosol particles, in real time, according not only to their chemical composition, but also to their size. This added information can be of critical importance when evaluating risks associated with aerosol particles of particular chemical composition. The apparatus achieves this beneficial result in a reliable fashion by first detecting the presence and size of individual aerosol particles moving along a predetermined particle path and by then directing a pulse of high-intensity light at the particle, to desorb and ionize the particle, for analysis of its chemical composition.