Light incandescence

Other ions interfere only when they are present in such concentration that with sodium hydroxide they yield precipitates whose colors prevent the observation of the color change due to magnesium. When very small quantities of magnesium are suspected, it is best to conduct the test under artificial light (incandescent bulbs) rather than in daylight. 

Light sources can either be broadband, such as a Globar, a Nemst glower, an incandescent wire or mercury arc lamp or they can be tunable, such as a laser or optical parametric oscillator (OPO). In the fomier case, a monocln-omator is needed to achieve spectral resolution. In the case of a tunable light source, the spectral resolution is detemiined by the linewidth of the source itself In either case, the spectral coverage of the light source imposes limits on the vibrational frequencies that can be measured. Of course, limitations on the dispersing element and detector also affect the overall spectral response of the spectrometer. 

Bromination in polar solvents usually gives /n j -3,4-dibromo-2-methyl-3-buten-2-ol in nonpolar solvents, with incandescent light, the cis isomer is the principal product (194). Chlorine adds readily up to the tetrachloro stage, but yields are low because of side reactions (195). 

Blue gas, or blue-water gas, so-called because of the color of the flame upon burning (10), was discovered in 1780 when steam was passed over incandescent carbon (qv), and the blue-water gas process was developed over the period 1859—1875. Successfiil commercial appHcation of the process came about in 1875 with the introduction of the carburetted gas jet. The heating value of the gas was low, ca 10.2 MJ /m (275 Btu/fT), and on occasion oil was added to the gas to enhance the heating value. The new product was given the name carburetted water gas and the technique satisfied part of the original aim by adding luminosity to gas lights (10). 

The ribbon machine employs a puff-and-blow method to make incandescent light bulb envelopes (1200/min), dashbulb envelopes (2000/min), Christmas tree ornaments, and the like (Fig. 15). For larger articles, the turret chain machine also uses the puff-and-blow method, but produces less cuUet and uses individual glass gobs rather than ribbon. 

Hafnium nitride s high, emissivity in the visible spectmm at high temperature has led to a proposed use (52) as a coating on incandescent light filaments to improve visible light output. 

The same properties that make molybdenum metal effective in high temperature furnace appHcations make it useful as support wires for tungsten filaments in incandescent light bulbs and as targets in x-ray tubes. 

Clearly, standardized light sources are desirable for color matching, particularly in view of the phenomenon of illuminant metamerism described below. Over the years CIE has defined several standard illuminants, some of which can be closely approximated by practical sources. In 1931 there was Source A, defined as a tungsten filament incandescent lamp at a color temperature of 2854 K. Sources B and C used filtering of A to simulate noon sunlight and north sky daylight, respectively. Subsequently a series of D illuminants was estabUshed to better represent natural daylight. Of these the most important is Illuminant E). ... 

Color from Incandescence. Any object emits light when heated, with the sequence of blackbody colors, black, red, orange, yellow, white, and bluish-white as the temperature increases. The locus of this sequence is shown on a chromaticity diagram in Eigure 14. 

Real or gray bodies deviate from these ideal blackbody values by the A-dependent emissivity, but the color sequence remains essentially the same. This mechanism explains the color of incandescent light sources such as flames in a candle, tungsten filament light bulb, flash bulb, carbon arc, limelight, lightning in part, and the incandescent part of pyrotechnics (qv). 

Such as motors (not really but can be considered so being balanced loads) heating loads, capacitor and incandescent lighting loads etc. Of the linear loads, the following will require special consideration. 

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