an oxygen concentrator is a device that concentrates the oxygen from a gas supply typically ambient air by selectively removing nitrogen to supply an oxygen-enriched product gas stream.. two methods in common use are pressure swing adsorption and membrane gas separation
copper concentrate is traded either via spot contracts or under long term contracts as an intermediate product in its own right. often the smelter sells the copper metal itself on behalf of the miner. the miner is paid the price at the time that the smelter-refiner makes the sale, not at the price on the date of delivery of the concentrate .
a polished object is heated in hot oil to 150–200 c for 10 minutes then cooled below 20 c, forming a sparkly surface covered with tiny facets. the alloy of 76% gold, 19% copper, and 5% aluminium yields a yellow color; the alloy of 76% gold, 18% copper and 6% aluminium is pink. green gold
hot rod was released by paramount pictures on august 3, 2007, and was a box office failure, grossing only $14 million of its $25 million budget. as the film's producers predicted, it received mixed reviews, with critics criticizing the film's script and humor. it has become a popular
a solar thermal collector collects heat by absorbing sunlight.the term 'solar collector' commonly refers to a device for solar hot water heating, but may refer to large power generating installations such as solar parabolic troughs and solar towers or non water heating devices such as solar air heaters.. solar thermal collectors are either non-concentrating or concentrating.
the axis of rotation for horizontal single axis tracker is horizontal with respect to the ground. the posts at either end of the axis of rotation of a horizontal single axis tracker can be shared between trackers to lower the installation cost. this type of solar tracker is most appropriate for low latitude regions. field layouts with .
in chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. several types of mathematical description can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration. a concentration can be any kind of chemical mixture, but most frequently solutes and solvents in solutions.