Impact of LED Color Temperatures on Perception Luminance in the Interior Zone of a Tunnel considering Fog Transmittance

Abstract

LEDs are widely applied in highways and tunnels for their long life, low light attenuation, and being environment friendly in recent years. The influence of correlated color temperature (CCT) of LED on lighting safety has attracted people’s attention as the demand increased. In this paper, a calculation model of perception luminance of human eye considering mesopic vision and fog concentration was proposed. The influence of different CCTs on perception luminance of human eye under different levels of fog concentration and luminance was calculated and analyzed. The CCT of LED employed in the interior zone of a tunnel was selected based on the highest perception luminance in mesopic vision. Seven kinds of LEDs with different CCTs (3000–6500K) were applied in the experimental system with adjustable fog concentrations. The results showed that the main factors affecting visual perception are luminance and fog concentration. Higher luminance or lower fog concentration provides drivers with higher perception luminance. In contrast, although CCT has a less effect on perception luminance, LEDs with higher CCT (about 6500K) can provide higher perception luminance considering fog in mesopic vision. This paper provides technical support for tunnel lighting and guaranteeing traffic safety.

The Relationship between Photoluminescence Emissions and Photocatalytic Activity of CeO2 Nanocrystals

“…Ethanol produces PL emission in the “ultra-warm” white region (3000 K) characteristic of incandescent light bulb emissions, whereas acetone-synthesized samples “are on” the “cool white” zone (4660 K) of the CIE diagram, related to daylight or an RGB monitor reference white point. A warm light region appears less bright to humans and is generally associated with resting areas (acetone, ∼3000 K), whereas samples emitting in cooler regions are indicated for working environments (ethanol, 4660 K) …”

“…A warm light region appears less bright to humans and is generally associated with resting areas (acetone, ∼3000 K), whereas samples emitting in cooler regions are indicated for working environments (ethanol, 4660 K). 88 Figure 7a−c shows photodegradation experiments using RhB dye solution as a model molecule to evaluate photocatalytic activity. Photocatalysis may be described as a threestep process: (I) target molecules are adsorbed on the surface of the catalyst; (II) radiation is absorbed by the catalyst producing photogenerated pairs (e − −h + ); and (III) redox reactions between molecules of the medium and the photogenerated pairs occur.…”

The influence of horizontal projection angle of low-position road light on visibility under fog conditions

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