scholarly journals Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods

2015 ◽  
Vol 370 (1667) ◽  
pp. 20140125 ◽  
Author(s):  
Travis Longcore ◽  
Hannah L. Aldern ◽  
John F. Eggers ◽  
Steve Flores ◽  
Lesly Franco ◽  
...  
Keyword(s):  
Los Angeles ◽  
White Light ◽  
Light Emitting Diode ◽  
Spectral Composition ◽  
Unintended Consequences ◽  
Light Spectrum ◽  
Ecological Processes ◽  
Light Emitting ◽  
Study Sites ◽  
Indoor Lighting

Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods.

The Color Mixing White-Light LEDs

2013 ◽  
Vol 378 ◽  
pp. 440-443
Author(s):  
Chiu Jung Yang ◽  
Chien Sheng Huang ◽  
Chih Wei Chen ◽  
Po Wen Chen
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Optical Power ◽  
Integrating Sphere ◽  
Light Spectrum ◽  
Light Emitting ◽  
Driver Circuit ◽  
Color Mixing ◽  
Color Rendering

Thepaperis discussedin coloruniformity study.The experiment divided into two steps in this study,first is modules design and simulation. Second is fabrication and measurement.After measure the LEDs property, calculating the ratio of each colored LEDs by using Grassmanns Law,modeling by Solidworks, and simulating the front study by optical software TracePro.Using four-color mixing with self-developed formula to avoid the present white light emitting diode patent, and the four-color grains are Red, Green, Blue and adding Y to modify the overall quality of the mixed light.The phosphorproduceSteabler-Wronsk hardly in the high temperatureas compared tofour-color mixing.Using four-color mixing to producehigher color rendering index than yellow phosphor.Series-parallel array of grain arrangement adopted to achieve the high demand for uniformity, while simplifying the design conditions by a certain current instead of the general mixed light-driven complex driver circuit,the completion of the mixing module using integrating sphere, light spectrum on the spectrophotometer, optical power, color coordinates values, such as mixing uniformity measurements.The chromaticity coordinates errors after complete results of the mixing module measurement and simulation can be controlled under (0.01x, 0.01y).

A low-cost spectrometer to analyse the purity of honey

2021 ◽  
Vol 57 (2) ◽  
pp. 025004
Author(s):  
L F Bestari ◽  
Sarwanto ◽  
Pujayanto ◽  
W P Syam ◽  
D Harjunowibowo
Keyword(s):  
Light Source ◽  
White Light ◽  
Measurement Accuracy ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Light Spectrum ◽  
Light Emitting ◽  
Average Accuracy

Abstract Light spectrum dispersion is an exciting subjectin science because of its beautiful atmospheric colour phenomenon which attracts students. However, to see the phenomenon is not easy since it needs a spectrometer, which is commonly expensive. Therefore, the present study aims to describe a low-cost spectrometer for investigating lighting spectrum and analysing the purity of honey as a pedagogical students’ project. The spectrometer was constructed from a webcam connected to a laptop, a free spectrometer software, DVD disk, and black cardboard. The calibration of the developed spectrometer used an Argon (Ar) lamp. Afterwards, measurement tests were carried out by using Neon (Ne) and Xenon (Xe) lamps. A white light-emitting diode was used as a light source to measure several types of honey wavelengths. The results from the experiment show that the wavelength of Ar, Ne, and Xe are (503 ± 4) nm, (463 ± 3) nm, and (451 ± 3) nm respectively. The measurement accuracy of the spectrometer is 99.5%. In addition, the commercial honey characterisations show that pure honey tends to have an excellent and smooth spectrum with one peak. On the contrary, the adulteries honeys show a rough wave with many peaks representing the inhomogeneous ingredients. It is found that the average accuracy for honey spectrum is 99.8%. Moreover, the low-cost spectrometer can be built and used easily by students for educational purposes.

scholarly journals Increased Plant Quality, Greenhouse Productivity and Energy Efficiency with Broad-Spectrum LED Systems: A Case Study for Thyme (Thymus vulgaris L.)

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 960
Author(s):  
Jenny Manuela Tabbert ◽  
Hartwig Schulz ◽  
Andrea Krähmer
Keyword(s):  
Broad Spectrum ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Thymus Vulgaris ◽  
Light Spectrum ◽  
Light Emitting ◽  
Biomass Yields ◽  
Lighting Systems

A light-emitting diode (LED) system covering plant-receptive wavebands from ultraviolet to far-red radiation (360 to 760 nm, “white” light spectrum) was investigated for greenhouse productions of Thymus vulgaris L. Biomass yields and amounts of terpenoids were examined, and the lights’ productivity and electrical efficiency were determined. All results were compared to two conventionally used light fixture types (high-pressure sodium lamps (HPS) and fluorescent lights (FL)) under naturally low irradiation conditions during fall and winter in Berlin, Germany. Under LED, development of Thymus vulgaris L. was highly accelerated resulting in distinct fresh yield increases per square meter by 43% and 82.4% compared to HPS and FL, respectively. Dry yields per square meter also increased by 43.1% and 88.6% under LED compared to the HPS and FL lighting systems. While composition of terpenoids remained unaffected, their quantity per gram of leaf dry matter significantly increased under LED and HPS as compared to FL. Further, the power consumption calculations revealed energy savings of 31.3% and 20.1% for LED and FL, respectively, compared to HPS. In conclusion, the implementation of a broad-spectrum LED system has tremendous potential for increasing quantity and quality of Thymus vulgaris L. during naturally insufficient light conditions while significantly reducing energy consumption.

scholarly journals The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1211
Author(s):  
Barbara Frąszczak ◽  
Monika Kula-Maximenko
Keyword(s):  
Chlorophyll Content ◽  
Blue Light ◽  
White Light ◽  
Leaf Shape ◽  
Red Light ◽  
Spectral Composition ◽  
Fresh Weight ◽  
Light Spectrum ◽  
Dark Green ◽  
Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

Solution-Processed White Light-Emitting Diode Utilizing Hybrid Polymer and Red–Green–Blue Quantum Dots

2012 ◽  
Vol 51 ◽  
pp. 09MH03
Author(s):  
Byoung Wook Kwon ◽  
Dong Ick Son ◽  
Dong-Hee Park ◽  
Heon-Jin Choi ◽  
Won-Kook Choi
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emitting Diode ◽  
Hybrid Polymer ◽  
Solution Processed ◽  
Light Emitting
Sign in / Sign up

Export Citation Format

Share Document