High pressure sodium lamp

Lamp types (a) incandescent and tungsten-halogen lamp shapes (b) fluorescent and compact fluorescent lamp shapes (c) typical high-pressure sodium lamp (d) typical metal halide lamp. 

Electrical Niobium is finding growing use in components for high-pressure sodium lamps. 

We wish to test a new type of ceramic tube to the AljOg tube normally used to fabricate high-pressure sodium lamps in order to eompare lamp qualities and life-time operation. Select a method which would produce the desired results and describe how this would be accomplished. Note that the ceramic tube requires both strength and a high melting point. 

Figure 2.2 The emission spectra of different spectral lamps (a) a low-pressure sodium lamp (b) a low-pressure mercury lamp (c) a high-pressure sodium lamp (d) a high-pressure mercury lamp.

Physics and Chemistry of High Pressure Sodium Lamps... 

In this review of the high pressure sodium lamp, emphasis is placed on evidence concerning the interaction of resonantly excited sodium atoms with sodium, mercury or xenon atoms, which modifies the spectral radiance of lamps to improve the color or efficacy. The influence of mercury and xenon buffer gases on tne thermal and electrical conductivities and hence on lamp efficacy are also indicated. 

The rest of this review will be limited to the high pressure sodium lamp. 

Recent reviews by deGroot et (1), Wharmby 2) and by McVey (3) summarize the scientific and technical aspects of the high pressure sodium lamp. Thus the present report has less need to be comprehensive and will tend instead to emphasize aspects of sodium and sodium-buffer gas interactions of interest to this symposium. We shall attempt to indicate areas where basic material data are either unknown or are inadequate. 

Finally, photolysis of 1-cyclopropyl-l-nitro-l-nitrosoethane at — 20°C, using a 400-W high-pressure sodium lamp, gave several products, which included cyclopropyl methyl ketone. The amount of this product produced was sensitive to the reaction conditions. ... 

High-pressure sodium lamps (sodium vapor pressure lO Pa). 

Plant growth conditions All A. thaliana plants were grown in controlled growth chambers, under continuous fluorescent illumination (150-200 pE m sec" ) at 22°C. All B. napus plants were grown under natural light supplemented with high pressure sodium lamps with a 16 hour photoperiod (16 h light/8 h dark), at 22°C, and a relative humidity of 25-30%. 

How effectively shonld yonr light source render colors The higher the color rendering index (CRI) of a lamp, the better individual colors will be rendered. The CRI compares how closely a light sonrce will render colors to a standard.The standard is usually an incandescent lamp, which is, by definition, a black body and has a CRI of 100, the highest rating (Table 5.40). Metal halide lamps nsnally have a CRI between 65 and 85. By comparison, high-pressure sodium lamps have a CRI of 22. 

Fig. 99.4 High-pressure sodium lamps that light Wallens Ridge are visible for miles...

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