Abstract: A light assembly (10) for installation in a greenhouse comprises a light unit (30) and at least one light fixture (20) mounted thereto. The light unit (30) comprises a light unit body comprising a light mounting structure (200), and a plurality of light sources mounted to the light unit body along a row. The light fixture (20) comprises a light fixture body comprising a light mounting structure (100) for mounting a light unit (30) thereto with thermal connection therebetween, a first passage (140) comprising an entry port (142) and an exit port (144) for a cooling fluid to circulate to dissipate heat conducted from the light unit (30) into the light fixture (20), a second passage (150) comprising an entry port (152) for receiving vaporizable compounds, and vaporization ports (160) fluidly connected to the second passage (150).

Abstract: A gas-metal-arc welding method is provided for high speed, high melting rate, substantially spatter-free, all-position welding. The method is particularly useful for out-of-position welding, that is, to produce vertical, inclined and overhead welds. A consumable wire electrode is held within and fed through the tubular contact tip of a continuous feed type welding gun having a tubular nozzle surrounding and extending beyond the tip. A shielding gas, formed of unique ratios of a minor proportion of a carbon dioxide and oxygen mixture combined with a major proportion of an argon and helium mixture, is flowed in a substantially longitudinally laminar pattern between the nozzle and contact tip and along the electrode extension from the tip. The contact tip is cooled, and sufficiently high power electrical current is passed through the contact tip and electrode extension to produce the arc and to melt the end of the electrode into molten drops for short-circuiting (e.g., low current) or for spray (e.g.