scholarly journals First Estimation of Global Trends in Nocturnal Power Emissions Reveals Acceleration of Light Pollution

2021 ◽  
Vol 13 (16) ◽  
pp. 3311
Author(s):  
Alejandro Sánchez de Miguel ◽  
Jonathan Bennie ◽  
Emma Rosenfeld ◽  
Simon Dzurjak ◽  
Kevin J. Gaston
Keyword(s):  
Light Emitting Diode ◽  
Visible Spectrum ◽  
Light Pollution ◽  
Limited Evidence ◽  
Night Time ◽  
Global Trends ◽  
Light Emitting ◽  
Global Spread ◽  
Satellite Sensors ◽  
Visible Wavelengths

The global spread of artificial light is eroding the natural night-time environment. The estimation of the pattern and rate of growth of light pollution on multi-decadal scales has nonetheless proven challenging. Here we show that the power of global satellite observable light emissions increased from 1992 to 2017 by at least 49%. We estimate the hidden impact of the transition to solid-state light-emitting diode (LED) technology, which increases emissions at visible wavelengths undetectable to existing satellite sensors, suggesting that the true increase in radiance in the visible spectrum may be as high as globally 270% and 400% on specific regions. These dynamics vary by region, but there is limited evidence that advances in lighting technology have led to decreased emissions.

scholarly journals Can light emitting diode-based road studs improve vehicle control in curves at night? A driving simulator study

2016 ◽  
Vol 50 (2) ◽  
pp. 266-281 ◽  
Author(s):  
A Shahar ◽  
R Brémond ◽  
C Villa
Keyword(s):  
Driving Simulator ◽  
Light Emitting Diode ◽  
Lateral Position ◽  
Vehicle Control ◽  
Night Time ◽  
Light Emitting ◽  
Road Lighting ◽  
Country Road ◽  
Simulator Study ◽  
Subjective Level

Road delineation treatments enhance the ability of drivers to control their vehicle safely on winding roads. A simulator experiment compared night-time driving on a country road under three conditions: on an unlit road, on a road illuminated on curves by typical road luminaires, and on a road with an active lane delineation application, where self-luminous road studs are turned on to outline the lane and road edges as the driver approaches and passes the curves. The unlit condition induces greater lateral position variability and longer crossovers relative to the studs condition, demonstrating better lateral vehicle control in the latter. The luminaires condition induce greater lateral position variability in left curves, and longer crossovers in right curves, relative to the studs condition, which also demonstrates a better lateral vehicle control in the studs condition. At a subjective level, the participants perceived both the studs condition and the luminaires condition as safer, more comfortable and allowing better control than the unlit road. It was concluded that the tested application enhanced the ability of drivers to control the virtual car, as compared to an unlit road or road lighting.

scholarly journals Visible blue light inhibits infection and replication of SARS-CoV-2 at doses that are well-tolerated by human respiratory tissue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nathan Stasko ◽  
Jacob F. Kocher ◽  
Abigail Annas ◽  
Ibrahim Henson ◽  
Theresa S. Seitz ◽  
...  
Keyword(s):  
Visible Light ◽  
Blue Light ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Spectral Band ◽  
Dependent Manner ◽  
Light Emitting ◽  
Biological Surfaces ◽  
Visible Wavelengths ◽  
High Doses

AbstractThe delivery of safe, visible wavelengths of light can be an effective, pathogen-agnostic, countermeasure that would expand the current portfolio of SARS-CoV-2 intervention strategies beyond the conventional approaches of vaccine, antibody, and antiviral therapeutics. Employing custom biological light units, that incorporate optically engineered light-emitting diode (LED) arrays, we harnessed monochromatic wavelengths of light for uniform delivery across biological surfaces. We demonstrated that primary 3D human tracheal/bronchial-derived epithelial tissues tolerated high doses of a narrow spectral band of visible light centered at a peak wavelength of 425 nm. We extended these studies to Vero E6 cells to understand how light may influence the viability of a mammalian cell line conventionally used for assaying SARS-CoV-2. The exposure of single-cell monolayers of Vero E6 cells to similar doses of 425 nm blue light resulted in viabilities that were dependent on dose and cell density. Doses of 425 nm blue light that are well-tolerated by Vero E6 cells also inhibited infection and replication of cell-associated SARS-CoV-2 by > 99% 24 h post-infection after a single five-minute light exposure. Moreover, the 425 nm blue light inactivated cell-free betacoronaviruses including SARS-CoV-1, MERS-CoV, and SARS-CoV-2 up to 99.99% in a dose-dependent manner. Importantly, clinically applicable doses of 425 nm blue light dramatically inhibited SARS-CoV-2 infection and replication in primary human 3D tracheal/bronchial tissue. Safe doses of visible light should be considered part of the strategic portfolio for the development of SARS-CoV-2 therapeutic countermeasures to mitigate coronavirus disease 2019 (COVID-19).

scholarly journals Controllable Synthesis of All Inorganic Lead Halide Perovskite Nanocrystals with Various Appearances in Multiligand Reaction System

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1751 ◽  
Author(s):  
Chen Chen ◽  
Louwen Zhang ◽  
Tielin Shi ◽  
Guanglan Liao ◽  
Zirong Tang
Keyword(s):  
Light Emitting Diode ◽  
Dominant Role ◽  
Photophysical Properties ◽  
Reaction System ◽  
Visible Spectrum ◽  
Peanut Oil ◽  
Light Emitting ◽  
Perovskite Nanocrystals ◽  
Halide Perovskite ◽  
Lead Halide

All inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals (PNCs) exhibit promising applications in light-emitting devices due to their excellent photophysical properties. Herein, we developed a low-cost and convenient method for the preparation of CsPbX3 PNCs in a multiligand-assisted reaction system where peanut oil is applied as a ligand source. The mixed-halide PNCs with tunable optical-band gap were prepared by mixing the single-halide perovskite solutions at room temperature. The resulting PNCs had good monodispersity, with dimensions of 8–10 nm, high photoluminescence quantum yield (96.9%), narrow emission widths (15–34 nm), and tunable emission wavelength (408–694 nm), covering the entire visible spectrum. Additionally, various morphologies of PNCs, such as nanospheres, nanocubes, and nanowires, were obtained by controlling reaction temperature and time, and the amount of oleamine with multiple ligands in peanut oil potentially playing a dominant role in the nucleation/growth processes of our PNCs. Finally, the resulting CsPbBr3 PNCs were employed to develop a white light-emitting diode (WLED), demonstrating the potential lighting applications for our method.

Behavioral response of adult caddisflies (Trichoptera) to blue and green light-emitting diode lamps

Zoosymposia ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 59-62
Author(s):  
GORO KIMURA ◽  
GORO TAJIKA ◽  
TOSHIHIRO KUSAMA ◽  
TSUTOMU TANIKAWA
Keyword(s):  
Uv Light ◽  
Diversity Index ◽  
Light Emitting Diode ◽  
Broad Band ◽  
Green Light ◽  
Visible Spectrum ◽  
Ultraviolet Spectrum ◽  
White Led ◽  
Light Emitting ◽  
Wiener Diversity Index

To clarify the effect of the visible spectrum, we collected Trichoptera adults using blue, green, and white light-emitting diode (LED) lamps and black light (BL) lamps. Except for white LED lamps, all lamps emitted broad-band wavelengths in the ultraviolet spectrum. A total of 212 adult Trichoptera were trapped. The most individuals were attracted by BL (96), followed blue (74), green (32), and white (10). Hydroptilidae spp. was the most abundant taxa among the lamps (183 individuals, 86.3%), followed by Cheumatopsyche brevilineata (23 individuals, 10.8%). Only Hydroptilidae spp. was common to all lamps. The Shannon–Wiener diversity index (H’) was highest at 0.96 for BL, followed by green (0.53), and blue (0.28). Trichoptera were attracted to both UV light and visible light. These results suggest that BL is the most useful for faunistic investigations of Trichoptera.

scholarly journals Multiple night-time light-emitting diode lighting strategies impact grassland invertebrate assemblages

2017 ◽  
Vol 23 (7) ◽  
pp. 2641-2648 ◽  
Author(s):  
Thomas W. Davies ◽  
Jonathan Bennie ◽  
Dave Cruse ◽  
Dan Blumgart ◽  
Richard Inger ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Night Time ◽  
Light Emitting ◽  
Invertebrate Assemblages

A Study on Energy Saving and Light Pollution of LED Advertising Signs

2011 ◽  
Vol 121-126 ◽  
pp. 2979-2984 ◽  
Author(s):  
Chen Ying Ho ◽  
Hsien Te Lin ◽  
Kuang Yu Huang
Keyword(s):  
Energy Consumption ◽  
Urban Areas ◽  
Light Emitting Diode ◽  
Outdoor Environment ◽  
Light Pollution ◽  
Light Emitting ◽  
Full Color ◽  
Average Luminance ◽  
Color Screens ◽  
Color Screen

Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.

scholarly journals Towards rare-earth-free white light-emitting diode devices based on the combination of dicyanomethylene and pyranine as organic dyes supported on zinc single-layered hydroxide

2019 ◽  
Vol 10 ◽  
pp. 760-770 ◽  
Author(s):  
Jeff L Nyalosaso ◽  
Rachod Boonsin ◽  
Pierre Vialat ◽  
Damien Boyer ◽  
Geneviève Chadeyron ◽  
...  
Keyword(s):  
White Light ◽  
Fluorescent Dyes ◽  
Light Emission ◽  
Organic Dyes ◽  
Light Emitting Diode ◽  
Composite Films ◽  
Visible Spectrum ◽  
Light Emitting ◽  
Blue Led ◽  
Display Devices

A new luminescent composite film resulting from the dispersion of luminescent organic dyes in a single-layered hydroxide (SLH)-type inorganic matrix has been developed. Two fluorescent organic dyes emitting visible light upon blue LED excitation were investigated in this study: dicyanomethylene (DCM) and pyranine (HPTS). These dyes exhibit broad emission bands that cover a large part of the visible spectrum. The concept developed in our work consisted in keeping SLH in its wet form to ensure a good dispersion of the fluorescent dyes prior to immobilizing the hybrid materials in a silicone polymer to achieve luminescent composite films. We demonstrate that these coatings stacked upon each other and placed above a blue LED lead to white-light emission with suitable photometric parameters for applications in lighting or display devices: colour temperature of 5409 K and colour rendering index (CRI) of 81.

Single-composition Al3+-singly doped ZnO phosphors for UV-pumped warm white light emitting diode applications

2021 ◽  
Author(s):  
Do Quang Trung ◽  
Nguyen Van Quang ◽  
Manh Trung Tran ◽  
Du Van Nguyen ◽  
Nguyen Tu ◽  
...  
Keyword(s):  
White Light ◽  
Light Quality ◽  
Light Emitting Diode ◽  
Broad Band ◽  
Visible Spectrum ◽  
Next Generation ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Warm White Light ◽  
Doped Zno

The development of full-visible-spectrum phosphors is essential for next-generation light-emitting devices with better light quality. Herein, we report on a novel broad-band-emitting phosphor based on single-composition Al-doped ZnO phosphor. Under...

Detection and Identification of Light-Emitting Diode Traffic Signals by Protan Observers

2003 ◽  
Vol 1844 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Michelle Kun Huang ◽  
John D. Bullough ◽  
Peter R. Boyce ◽  
Andrew Bierman
Keyword(s):  
Light Emitting Diode ◽  
Visible Spectrum ◽  
Normal Subjects ◽  
Traffic Signals ◽  
Detection Performance ◽  
Identification Accuracy ◽  
Dominant Wavelength ◽  
Light Emitting ◽  
Red Led ◽  
Color Identification

Protan observers have lower spectral sensitivity than color-normal observers at long wavelengths of the visible spectrum. Responses of protan and color-normal subjects to light emitting diode (LED) and incandescent traffic signals of red and yellow nominal color during simulated daytime viewing conditions are described. Reaction times, missed signal percentages, and color-identification accuracy were measured. The results indicate that for protans, detection performance to red LED signals was enhanced when the dominant wavelength was moved toward shorter wavelengths, but this shift also appeared to decrease their ability to correctly identify the signal color. Although the yellow LED signal used in this study provided similar detection performance for protans as a yellow incandescent signal, its dominant wavelength was sufficiently long for it to sometimes be confused with red. In general, the results of this study are consistent with the 1994 recommendations of the Commission Internationale de l’Éclairage for signal colors to be seen by color-normal and protan observers. Nonetheless, neither detection nor color identification for protans approached that of color-normal observers.

Estimating Fatality and Injury Savings Because of Deployment of Advanced Wrong-Way Driving Countermeasures on a Toll Road Network

2021 ◽  
pp. 036119812098657
Author(s):  
Adrian Sandt ◽  
Haitham Al-Deek
Keyword(s):  
Life Cycle ◽  
Capital Investment ◽  
Road Network ◽  
Light Emitting Diode ◽  
Night Time ◽  
Light Emitting ◽  
Limited Access ◽  
Toll Road ◽  
Improved Performance ◽  
Benefit Cost

Limited access facility wrong-way driving (WWD) crashes are typically more severe than other crashes. Deploying advanced WWD countermeasures, such as rectangular flashing beacon (RFB) and light-emitting diode (LED) technologies, at exit ramps can reduce WWD crashes, injuries, and fatalities. No previous research has developed a methodology to quantify the potential fatality and injury savings because of future countermeasure deployments. This paper developed such a methodology and applied it to Florida’s Turnpike Enterprise (FTE) toll road network. From 2011–2016, there were 53 FTE WWD crashes, resulting in 16 fatalities and annual injury costs of $37 million. The proportion of these crashes occurring during night-time was 87%. RFB and LED life-cycle injury savings and costs were determined for all 216 FTE exits. The total savings were $424 million for RFBs (benefit–cost [B/C] ratio of 23.20) and $144 million for LEDs (B/C ratio of 13.13). Deploying countermeasures at the 103 exits with the highest B/C ratios would provide 70% of the total possible savings by equipping 40% of the ramps. For the same capital investment, RFBs provide more savings than LEDs. Spending $1 million to deploy RFBs will provide similar savings as spending $3.4 million to deploy LEDs. Evaluating the existing FTE RFB and LED ramps shows that RFBs are more effective at night-time and can provide three times the savings of LEDs. The results of this paper show the improved performance of RFBs over LEDs and provide an example that other agencies could follow to identify savings and cost-effectively deploy advanced WWD countermeasures.

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