Incandescent light bulb Small variations in resistivity along the filament cause "hot spots" to form at points of higher resistivity; a variation of diameter of only 1% will cause a 25% reduction in service life. These hot spots evaporate faster than the rest of the filament, which increases the resistance at that point—this creates a positive feedback that ends in the familiar tiny gap in an otherwise healthy-looking filament. Irving Langmuir found that an inert gas, instead of vacuum, would retard evaporation. General service incandescent light bulbs over about 25 watts in rating are now filled with a mixture of mostly argon and
Multiple inert gas elimination technique Multiple inert gas elimination technique The multiple inert gas elimination technique (MIGET) is a medical technique used mainly in pulmonology that involves measuring the concentrations of various infused, inert gases in mixed venous blood, arterial blood, and expired gas of a subject. The technique quantifies true shunt, physiological dead space ventilation, ventilation versus blood flow (V/Q) ratios, and diffusion limitation. Hypoxemia is generally attributed to one of four processes: hypoventilation, shunt (right to left), diffusion limitation, and ventilation/perfusion (V/Q) inequality. Moreover, there are also "extrapulmonary" factors that can contribute to fluctuations in arterial PO. There are several measures of hypoxemia