Long-Term Comparison of Attraction of Flying Insects to Streetlights after the Transition from Traditional Light Sources to Light-Emitting Diodes in Urban and Peri-Urban Settings

Among the different light sources used for street lighting, light-emitting diodes (LEDs) are likely to dominate the world market in the coming years. At the same time, the spectral composition of nocturnal illumination is changing. Europe and many other areas worldwide have implemented bans on energy-inefficient lamps, such as the still very common mercury vapor lamps. However, the impact of artificial light on insects is mostly tested with light-traps or flight-intercept traps that are used for short periods only. By comparing the numbers of insects attracted by street lamps before and after replacing mercury vapor light sources (MV) with light emitting diodes, we assessed the impact in more typical (urban and peri-urban) settings over several years. We found that LED attracted approximately half of the number of insects compared to MV lights. Furthermore, most insect groups are less drawn by LED than by MV, while Hymenoptera are less attracted by MV than by LED. Thus, the composition of the attracted communities differed between the light sources, which may impact ecosystem processes and functions. In green peri-urban settings more insects are attracted than in an urban setting, but the relative difference between the light sources is the same.

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Cuttings of Impatiens, Pelargonium, and Petunia Propagated under Light-emitting Diodes and High-pressure Sodium Lamps Have Comparable Growth, Morphology, Gas Exchange, and Post-transplant Performance

HortScience ◽

10.21273/hortsci.48.4.428 ◽

2013 ◽

Vol 48 (4) ◽

pp. 428-434 ◽

Cited By ~ 26

Author(s):

Christopher J. Currey ◽

Roberto G. Lopez

Keyword(s):

High Pressure ◽

Gas Exchange ◽

Light Emitting Diodes ◽

Dry Mass ◽

Stem Length ◽

Light Sources ◽

Growth Morphology ◽

Light Emitting ◽

Supplemental Lighting ◽

The Impact

Increasing photosynthetic daily light integral (DLI) by supplementing with high-pressure sodium (HPS) lamps during propagation has been shown to enhance photosynthesis and biomass accumulation of cuttings. The development of high-intensity light-emitting diodes (LEDs) is a promising technology with potential as a greenhouse supplemental lighting source. Our objective was to quantify the impact of narrow spectra supplemental lighting from LEDs on growth, morphology, and gas exchange of cuttings compared with traditional HPS supplemental lighting. Cuttings of Impatiens hawkeri W. Bull ‘Celebrette Frost’, Pelargonium ×hortorum L.H. Bailey ‘Designer Bright Red’, and Petunia ×hybrida Vilm. ‘Suncatcher Midnight Blue’ were received from a commercial propagator and propagated in a glass-glazed greenhouse at 23 °C air and substrate temperature set points. After callusing (≈5 mol·m−2·d−1 for 7 days), cuttings were placed under 70 μmol·m−2·s−1 delivered from HPS lamps or LED arrays with varying proportions (%) of red:blue light (100:0, 85:15, or 70:30). After 14 days under supplemental lighting treatments, growth, morphology, and gas exchange of rooted cuttings were measured. There were no significant differences among Impatiens and Pelargonium cuttings grown under different supplemental light sources. However, compared with cuttings propagated under HPS lamps, stem length of Petunia cuttings grown under 100:0 red:blue LEDs was 11% shorter, whereas leaf dry mass, root dry mass, root mass ratios, and root:shoot ratio of cuttings grown under 70:30 red:blue LEDs were 15%, 36%, 17%, and 24% higher, respectively. Supplemental light source had minimal impact on plants after transplant. Our data suggest that LEDs are suitable replacements for HPS lamps as supplemental light sources during cutting propagation.

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Application of Light-Emitting Diodes for Improving the Nutritional Quality and Bioactive Compound Levels of Some Crops and Medicinal Plants

Molecules ◽

10.3390/molecules26051477 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1477

Author(s):

Woo-Suk Jung ◽

Ill-Min Chung ◽

Myeong Ha Hwang ◽

Seung-Hyun Kim ◽

Chang Yeon Yu ◽

...

Keyword(s):

Plant Growth ◽

In Vitro Culture ◽

Light Emitting Diodes ◽

Photosynthetic Pigment ◽

Antioxidant Properties ◽

Light Sources ◽

Light Emitting ◽

Cell Defense ◽

Led Irradiation

Light is a key factor that affects phytochemical synthesis and accumulation in plants. Due to limitations of the environment or cultivated land, there is an urgent need to develop indoor cultivation systems to obtain higher yields with increased phytochemical concentrations using convenient light sources. Light-emitting diodes (LEDs) have several advantages, including consumption of lesser power, longer half-life, higher efficacy, and wider variation in the spectral wavelength than traditional light sources; therefore, these devices are preferred for in vitro culture and indoor plant growth. Moreover, LED irradiation of seedlings enhances plant biomass, nutrient and secondary metabolite levels, and antioxidant properties. Specifically, red and blue LED irradiation exerts strong effects on photosynthesis, stomatal functioning, phototropism, photomorphogenesis, and photosynthetic pigment levels. Additionally, ex vitro plantlet development and acclimatization can be enhanced by regulating the spectral properties of LEDs. Applying an appropriate LED spectral wavelength significantly increases antioxidant enzyme activity in plants, thereby enhancing the cell defense system and providing protection from oxidative damage. Since different plant species respond differently to lighting in the cultivation environment, it is necessary to evaluate specific wavebands before large-scale LED application for controlled in vitro plant growth. This review focuses on the most recent advances and applications of LEDs for in vitro culture organogenesis. The mechanisms underlying the production of different phytochemicals, including phenolics, flavonoids, carotenoids, anthocyanins, and antioxidant enzymes, have also been discussed.

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Electrically driven single microribbon based near-infrared exciton-polariton light-emitting diode

CrystEngComm ◽

10.1039/d1ce00419k ◽

2021 ◽

Author(s):

Mingming Jiang ◽

Fupeng Zhang ◽

Kai Tang ◽

Peng Wan ◽

Caixia Kan

Keyword(s):

High Performance ◽

Near Infrared ◽

Light Emitting Diodes ◽

Light Emitting Diode ◽

Light Sources ◽

Coherent Light ◽

Light Emitting ◽

Exciton Polaritons ◽

Laser Devices

Achieving electrically-driven exciton-polaritons has drawn substantial attention toward developing ultralow-threshold coherent light sources, containing polariton laser devices and high-performance light-emitting diodes (LEDs). In this work, we demonstrate an electrically driven...

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Four color stacked white organic light-emitting diodes utilizing the concept of triplet harvesting

MRS Proceedings ◽

10.1557/opl.2011.3 ◽

2011 ◽

Vol 1286 ◽

Author(s):

Th. C. Rosenow ◽

S. Olthof ◽

S. Reineke ◽

B. Lüssem ◽

K. Leo

Keyword(s):

Light Emitting Diodes ◽

Blue Emission ◽

Organic Light Emitting Diodes ◽

Light Sources ◽

Emission Layer ◽

Light Emitting ◽

Organic Light ◽

Blue Emitters ◽

Color Rendering ◽

Triplet Harvesting

ABSTRACTOrganic light-emitting diodes (OLEDs) are developing into a competitive alternative to conventional light sources. Nevertheless, OLEDs need further improvement in terms of efficiency and color rendering for lighting applications. Fluorescent blue emitters allow deep blue emission and high stability, while phosphorescent blue emitter still suffer from insufficient stability. The concept of triplet harvesting is the key for achieving internal quantum efficiencies up to 100 % and simultaneously benefiting from the advantages of fluorescent blue emitters. Here, we present a stacked OLED consisting of two units comprising four different emitters in total. The first unit takes advantage of the concept of triplet harvesting and combines the light emission of a fluorescent blue and a phosphorescent red emitter. The second unit emits light from a single emission layer consisting of a matrix doped with phosphorescent green and yellow emitters. With this approach, we reach white color coordinates close to the standard illuminant A and a color rendering index of above 75. The presented devices are characterized by high luminous efficacies of above 30 lm/W on standard glass substrates without outcoupling enhancement.

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Assessing the impact of the transition to Light Emitting Diodes based solar lighting systems in India

Energy for Sustainable Development ◽

10.1016/j.esd.2013.03.005 ◽

2013 ◽

Vol 17 (4) ◽

pp. 363-370 ◽

Cited By ~ 9

Author(s):

Santosh M. Harish ◽

Shuba V. Raghavan ◽

Milind Kandlikar ◽

Gireesh Shrimali

Keyword(s):

Light Emitting Diodes ◽

Light Emitting ◽

Solar Lighting ◽

Lighting Systems ◽

The Impact

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Characterization of a simple and homogeneous irradiation device based on light-emitting diodes: A possible low-cost supplement to conventional light sources for photodynamic treatment

Medical Laser Application ◽

10.1016/j.mla.2006.07.004 ◽

2006 ◽

Vol 21 (4) ◽

pp. 277-283 ◽

Cited By ~ 28

Author(s):

Anja Pieslinger ◽

Kristjan Plaetzer ◽

Christian Benno Oberdanner ◽

Juergen Berlanda ◽

Heidemarie Mair ◽

...

Keyword(s):

Light Emitting Diodes ◽

Low Cost ◽

Light Sources ◽

Photodynamic Treatment ◽

Light Emitting ◽

Homogeneous Irradiation ◽

Irradiation Device

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Centers for Disease Control-type light traps equipped with high-intensity light-emitting diodes as light sources for monitoring Anopheles mosquitoes

Acta Tropica ◽

10.1016/j.actatropica.2018.04.013 ◽

2018 ◽

Vol 183 ◽

pp. 61-63 ◽

Cited By ~ 7

Author(s):

Benedita Maria Costa-Neta ◽

Abdias Ribeiro Lima-Neto ◽

Apoliana Araújo da Silva ◽

Jefferson Mesquita Brito ◽

João Vitor Castro Aguiar ◽

...

Keyword(s):

Disease Control ◽

High Intensity ◽

Light Emitting Diodes ◽

Light Sources ◽

Light Traps ◽

Light Emitting ◽

Anopheles Mosquitoes ◽

Centers For Disease Control ◽

High Intensity Light

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Studies of Degradation in Nichia AlGaN/InGaN/GaN Blue Light Emitting Diodes Under Close to Normal Operating Conditions

MRS Proceedings ◽

10.1557/proc-421-183 ◽

1996 ◽

Vol 421 ◽

Author(s):

M. Osiński ◽

D. L. Barton ◽

C. J. Helms ◽

P. Perlin ◽

N. H. Berg ◽

...

Keyword(s):

Blue Light ◽

Light Emitting Diodes ◽

Defect Density ◽

Degradation Process ◽

Operating Conditions ◽

Similar Amount ◽

Life Testing ◽

Light Emitting ◽

High Pulsed Current ◽

The Impact

AbstractThe reliability of devices fabricated in GaN and related alloys, especially under high current densities as would be found in lasers, has yet to be fully characterized. Our previous work [1] investigated the degradation of GaN-based blue light emitting diodes (LEDs) under high pulsed current stress. This work indicated a possible correlation between the high crystal defect density and failures caused by metal migration along these defect tubes. To assess the impact of this data on devices under more normal conditions, several LEDs from both older and more recent production lots were placed in a controlled temperature and current environment for several thousand hours. The test started with a constant 20 mA current for the first 1000 hours and continued for another 1650 hours at various currents up to 70 mA, all at a temperature of 23 °C. During this test, one of the older generation LED's output degraded by more than 50%. Subsequent failure analysis showed that this was caused by a crack which isolated part of the active region from the p-contact. The remaining LEDs were returned to life testing where the temperature was subsequently increased by 5 °C after each 500 hours of testing. The output from one of the newer LEDs dreiven at 70 mA degraded to 55% of its original value after 3600 hours and a second newer LED degraded by a similar amount after 4400 hours. The first failure, LED #16, did not exhibit a significant change in its I-V characteristics indicating that a change in the package transparency was a likely cause for the observed degradation. The second failure, LED #17, did show a noticeable change in its I-V characteristics. This device was subsequently returned to life testing where the degradation process will be monitored for further changes.

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