scholarly journals Multi-Wavelength Densitometer for Experimental Research on the Optical Characteristics of Smoke Layers

2021 ◽  
Author(s):  
Wojciech Węgrzyński ◽  
Piotr Antosiewicz ◽  
Jadwiga Fangrat
Keyword(s):  
Blue Light ◽  
Red Light ◽  
Test Chamber ◽  
Added Value ◽  
Light Extinction ◽  
Warm Up ◽  
Light Emitting ◽  
Light Obscuration ◽  
Multi Wavelength ◽  
In Fire

AbstractA novel multi-wavelength densitometer was built for the purpose of continuous and simultaneous measurements of light obscuration in smoke layers, concurrently in five bands (λ = 450 nm, 520 nm, 658 nm, 830 nm and 980 nm). This device was used for determining transmittance and visibility in smoke parameters of a smoke layer from the fire of 1.00 dm3 of n-Heptane in a 0.33 × 0.33 m tray located in a test chamber (9.60 × 9.80 × 4.00 m3). The performance of the device was compared with a commercial Lorenz densitometer at 880 nm. Significant differences in measured value of transmittance were observed between the different sensors – from 65% at 450 nm (blue light), 80% at 658 nm (red light) to 95% at 980 nm (IR). The visibility in smoke, estimated following the theory of Jin for light reflecting signs (K = 3), ranged from 7.5 m (blue light) to 12 m (red light) and for the light-emitting (K = 8) signs from 18 to 32 m, respectively. The performed experiment has confirmed the applicability and added value of multi-wavelength measurements of light-extinction in fire experiments. The device was sensitive to temperature variations and requires active cooling and careful warm-up prior to experiments, to reach the expected sensitivity.

(K0.5Na0.5)NbO3:Eu3+/Bi3+: a novel, highly efficient, red light-emitting material with superior water resistance behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao
Keyword(s):  
Blue Light ◽  
White Light ◽  
High Performance ◽  
Water Resistance ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Light Emitting ◽  
Highly Efficient ◽  
White Light Emitting Diodes

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).

scholarly journals Suppression of Cucumber Powdery Mildew by Supplemental UV-B Radiation in Greenhouses Can be Augmented or Reduced by Background Radiation Quality

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1349-1357 ◽  
Author(s):  
A. Suthaparan ◽  
A. Stensvand ◽  
K. A. Solhaug ◽  
S. Torre ◽  
K. H. Telfer ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Blue Light ◽  
Background Radiation ◽  
Red Light ◽  
Ultraviolet B ◽  
Disease Suppression ◽  
Radiation Quality ◽  
Light Emitting ◽  
Cucumber Powdery Mildew ◽  
Yellow Orange

This study demonstrates that the spectral quality of radiation sources applied with ultraviolet-B (UV-B; background radiation) affects the suppression of cucumber powdery mildew (Podosphaera xanthii) by UV-B. Suppression provided by daily UV-B exposure of 1 W/m2 for 10 min was greatest in the presence of red light or by a complete lack of background light, and powdery mildew suppression was least in the presence of ultraviolet-A (UV-A) or blue radiation compared with plants exposed only to 16 h of daily natural light supplemented with high-pressure sodium lamps that supply broad-spectrum radiation with peaks in the yellow-orange region. Exposure of powdery mildew-inoculated plants to supplemental red light without UV-B, beginning at the end of the daylight period, also reduced disease severity; however, supplemental blue light applied in the same fashion had no effect. Daily application of UV-B at 1 W/m2 beginning on the day of inoculation significantly reduced the severity of powdery mildew to 15% compared with 100% severity on control plants. Maximum suppression of powdery mildew was observed following 15 min of exposure to UV-B (1.1% severity compared with 100% severity on control plants) but exposure time had to be limited to 5 to 10 min to reduce phytotoxicity. There was no additional disease suppression when plants were exposed to UV-B beginning 2 days prior to inoculation compared with plants exposed to UV-B beginning on the day of inoculation. UV-B inhibited germination, infection, colony expansion, and sporulation of P. xanthii. The results suggest that efficacy of UV-B treatments, alone or in combination with red light, against P. xanthii can be enhanced by exposure of inoculated plants to these wavelengths of radiation during the night, thereby circumventing the counteracting effects of blue light and UV-A radiation. The effect of UV-B on powdery mildew seemed to be directly upon the pathogen, rather than induced resistance of the host. Night exposure of plants to 5 to 10 min of UV-B at 1 W/m2 and inexpensive, spectral-specific, light-emitting diodes may provide additional tools to suppress powdery mildews of diverse greenhouse crops.

Driving and Application of Blue Light Organic Light Emitting Devices

2019 ◽  
Vol 11 (5) ◽  
pp. 711-717
Author(s):  
Hongbo Liu ◽  
Minghui Liu ◽  
Lin Cong ◽  
Lizhong Wang ◽  
Tao Huang ◽  
...  
Keyword(s):  
Blue Light ◽  
High Efficiency ◽  
Low Voltage ◽  
Red Light ◽  
Portable Devices ◽  
Driving Voltage ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Organic Light ◽  
Organic Light Emitting Devices

The DPVBi (4,4′-bis(2,2-diphenylvinyl-1,1′-biphenyl) is a blue-light organic fluorescence doped material, which can be used as a hole barrier layer or a luminescent layer for fabricating organic light-emitting devices. A blue light device with stable color stability and high efficiency was prepared by co-doping blue light dye DPVBi and red light dye DCJTB as light-emitting layer. In order to prevent the infiltration of O2 and moisture inside the device from affecting the luminescence lifetime of the device, the device was encapsulated by atomic layer deposition. Since the driving voltage of the organic light-emitting device is generally above 5 V and the power consumption is low, in order to facilitate driving with a low voltage, a boost driving circuit based on the XL6009 chip was designed. The driver of the fabricated blue-light device was tested. The results showed that circuit had low-voltage drive characteristics and could be widely used in small toys, lighting, and portable devices. Through the test to achieve the desired goal, the requirements of low voltage and low energy consumption were realized, and the life of the light-emitting device can be tested, which has certain practicability and reference value.

scholarly journals Growth and Bioactive Compound Synthesis in Cultivated Lettuce Subject to Light-quality Changes

HortScience ◽  
2017 ◽  
Vol 52 (4) ◽  
pp. 584-591 ◽  
Author(s):  
Ki-Ho Son ◽  
Jin-Hui Lee ◽  
Youngjae Oh ◽  
Daeil Kim ◽  
Myung-Min Oh ◽  
...  
Keyword(s):  
Blue Light ◽  
Bioactive Compounds ◽  
Light Quality ◽  
Red Light ◽  
Monochromatic Light ◽  
Bioactive Compound ◽  
Light Emitting ◽  
Compound Synthesis ◽  
Plant Factory ◽  
Ferulic Acids

This study aimed to determine the effect of changes in light quality on the improvement of growth and bioactive compound synthesis in red-leaf lettuce (Lactuca sativa L. ‘Sunmang’) grown in a plant factory with electrical lighting. Lettuce seedlings were subjected to 12 light treatments combining five lighting sources: red (R; 655 nm), blue (B; 456 nm), and different ratios of red and blue light combined with three light-emitting diodes [LEDs (R9B1, R8B2, and R6B4)]. Treatments were divided into control (continuous irradiation of each light source for 4 weeks), monochromatic (changing from R to B at 1, 2, or 3 weeks after the onset of the experiments), and combined (changing from R9B1 to R8B2 or R6B4 at 2 or 3 weeks after the onset of the experiments). Growth and photosynthetic rates of lettuce increased with increasing ratios of red light, whereas chlorophyll and antioxidant phenolic content decreased with increasing ratios of red light. Individual phenolic compounds, including chlorogenic, caffeic, chicoric, and ferulic acids, and kaempferol, showed a similar trend to that of total phenolics. Moreover, transcript levels of phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) genes were rapidly upregulated by changing light quality from red to blue. Although the concentration of bioactive compounds in lettuce leaves enhanced with blue light, their contents per lettuce plant were more directly affected by red light, suggesting that biomass as well as bioactive compounds’ accumulation should be considered to enhance phytochemical production. In addition, results suggested that growth and antioxidant phenolic compound synthesis were more sensitive to monochromatic light than to combined light variations. In conclusion, the adjustment of light quality at a specific growth stage should be considered as a strategic tool for improving crop yield, nutritional quality, or both in a plant factory with electrical lighting.

scholarly journals A Novel Red-Emitting Na2NbOF5:Mn4+ Phosphor with Ultrahigh Color Purity for Warm White Lighting and Wide-Gamut Backlight Displays

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5317
Author(s):  
Jingshan Hou ◽  
Wenxiang Yin ◽  
Langping Dong ◽  
Yang Li ◽  
Yufeng Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Red Light ◽  
Luminescent Properties ◽  
Fluorescence Decay ◽  
Color Temperature ◽  
Color Purity ◽  
Zero Phonon Line ◽  
Light Emitting

In this work, a novel red-emitting oxyfluoride phosphor Na2NbOF5:Mn4+ with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of Na2NbOF5:Mn4+ were studied in detail. The photoluminescence excitation spectrum contains two intense excitation bands centered at 369 and 470 nm, which match well with commercial UV and blue light-emitting diode (LED) chips. When excited by 470 nm blue light, Na2NbOF5:Mn4+ exhibits red light emission dominated by ZPL. Notably, the color purity of the Na2NbOF5:Mn4+ red phosphor can reach 99.9%. Meanwhile, the Na2NbOF5:Mn4+ phosphor has a shorter fluorescence decay time than commercial K2SiF6:Mn4+, which is conducive to fast switching of images in display applications. Profiting from the intense ZPL, white light-emitting diode (WLED) with high color rendering index of Ra = 86.2 and low correlated color temperature of Tc = 3133 K is realized using yellow YAG:Ce3+ and red Na2NbOF5:Mn4+ phosphor. The WLED fabricated using CsPbBr3 quantum dots (QDs) and red Na2NbOF5:Mn4+ phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting Na2NbOF5:Mn4+ phosphor has potential application prospects in WLED lighting and display backlight.

scholarly journals Blue Light-emitting Diode Light Irradiation of Seedlings Improves Seedling Quality and Growth after Transplanting in Red Leaf Lettuce

HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1809-1814 ◽  
Author(s):  
Masahumi Johkan ◽  
Kazuhiro Shoji ◽  
Fumiyuki Goto ◽  
Shin-nosuke Hashida ◽  
Toshihiro Yoshihara
Keyword(s):  
Leaf Area ◽  
Blue Light ◽  
Antioxidant Activities ◽  
Light Emitting Diode ◽  
Red Light ◽  
Seedling Quality ◽  
Carotenoid Content ◽  
Light Emitting ◽  
Leaf Lettuce ◽  
Led Lights

In this study, we determined the effects of raising seedlings with different light spectra such as with blue, red, and blue + red light-emitting diode (LED) lights on seedling quality and yield of red leaf lettuce plants. The light treatments we used were applied for a period of 1 week and consisted of 100 μmol·m−2·s−1 of blue light, simultaneous irradiation with 50 μmol·m−2·s−1 of blue light and 50 μmol·m−2·s−1 of red light, and 100 μmol·m−2·s−1 of red light. At the end of the light treatment, that is 17 days after sowing (DAS), the leaf area and shoot fresh weight (FW) of the lettuce seedlings treated with red light increased by 33% and 25%, respectively, and the dry weight of the shoots and roots of the lettuce seedlings treated with blue-containing LED lights increased by greater than 29% and greater than 83% compared with seedlings grown under a white fluorescent lamp (FL). The shoot/root ratio and specific leaf area of plants irradiated with blue-containing LED lights decreased. At 45 DAS, higher leaf areas and FWs were obtained in lettuce plants treated with blue-containing LED lights. The total chlorophyll (Chl) contents in lettuce plants treated with blue-containing and red lights were less than that of lettuce plants treated with FL, but the Chl a/b ratio and carotenoid content increased under blue-containing LED lights. Polyphenol contents and the total antioxidant status (TAS) were greater in lettuce seedlings treated with blue-containing LED lights than in those treated with FL at 17 DAS. The higher polyphenol contents and TAS in lettuce seedlings at 17 DAS decreased in lettuce plants at 45 DAS. In conclusion, our results indicate that raising seedlings treated with blue light promoted the growth of lettuce plants after transplanting. This is likely because of high shoot and root biomasses, a high content of photosynthetic pigments, and high antioxidant activities in the lettuce seedlings before transplanting. The compact morphology of lettuce seedlings treated with blue LED light would be also useful for transplanting.

scholarly journals The Effects of Various LED Light Wavelengths to the Physiological and Morphological Parameters of Stevia (Stevia rebaudiana) Bertoni

2016 ◽  
Vol 8 (3) ◽  
pp. 354-359
Author(s):  
Esra UCAR ◽  
Nuri CAGLAYAN ◽  
Kenan TURGUT
Keyword(s):  
Blue Light ◽  
Red Light ◽  
Stevia Rebaudiana ◽  
Stem Length ◽  
Electromagnetic Spectrum ◽  
Morphological Parameters ◽  
Light Emitting ◽  
Stevia Rebaudiana Bertoni ◽  
A Value ◽  
Yield Values

In this study, it was investigated the growth of stevia (Stevia rebaudiana Bertoni) under various wavelengths of LED lamp (Light Emitting Diodes), which can emit daylight (cool white; 400–700 nm), red (620–630 nm) and blue (465–485 nm) wavelengths of the light in the electromagnetic spectrum. In all applications, quantity of PAR (photosynthetically active radiation) was adjusted as 150 µmol.m-2 s-1. Study had maintained in plant breeding cabin 16 hours light and 8 hours dark environment. Results demonstrated that while the highest plant height was determined in the “30% blue light+ 70% red light” application, the highest stem length was found in the “50% blue light + 50% red light” application. In addition, the number of the stems reached the highest value in the “70% blue light + 30% red light” application. Consequently, a correlation was observed between negative “a” value and the amount of chlorophyll. Because of the hereby obtained results, comparing to other applications, the “50% blue light + 50% red light” was found as the best light application to obtain optimum yield values of stevia.

scholarly journals Growth of Potato Plantlets In Vitro Is Different When Provided Concurrent Versus Alternating Blue and Red Light Photoperiods

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 380-382 ◽  
Author(s):  
Ruey-Chi Jao ◽  
Wei Fang
Keyword(s):  
Blue Light ◽  
Red Light ◽  
Dry Weight ◽  
Optimal Growth ◽  
Similar Proportion ◽  
Light Emitting ◽  
Long Duration ◽  
Plantlet Growth ◽  
Potato Plantlets

Effects of concurrent vs. alternating blue and red light using light-emitting diodes (LEDs) on the photomixotrophic growth of potato plantlets in vitro were investigated. All seven treatments had the same 5.53 mol·m-2 daily light integral (DLI), photoperiod (16-hour day/8-hour night) and similar proportion of red light (45%) and blue light (55%). Results showed that the fresh/dry weight accumulation of potato plantlets in vitro under the concurrent blue and red light was superior than that under the alternating blue and red light, indicating that the simultaneous coexistence of blue and red light are necessary for optimum plantlet growth. Low PPF with long duration was better than high PPF with short duration under same DLI. Within the concurrent blue and red light treatments, when the duration of blue light was shorter than that of red light, timing of the blue light affected the growth of potato plantlets in vitro. Providing blue and red light together at the beginning of the photoperiod resulted in optimal growth, however plantlets illuminated with alternately blue and red light had significantly less fresh/dry weight accumulation.

scholarly journals The Proportion of Blue Light from Light-emitting Diodes Alters Microgreen Phytochemical Profiles in a Species-specific Manner

HortScience ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 13-20
Author(s):  
Qinglu Ying ◽  
Chase Jones-Baumgardt ◽  
Youbin Zheng ◽  
Gale Bozzo
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Total Carotenoids ◽  
Total Anthocyanin ◽  
Light Emitting ◽  
Red Cabbage ◽  
Species Specific ◽  
A Minor ◽  
The Impact

Microgreens are specialty vegetables that contain human health-promoting phytochemicals. Typically, microgreens are cultivated in controlled environments under red and blue light-emitting diodes (LEDs). However, the impact of varying the proportions of these light qualities on the composition of diverse phytochemicals in indoor-grown microgreens is unclear. To address this problem, the levels of chlorophylls, carotenoids, ascorbates, phenolics, anthocyanins, and nitrate were examined in arugula (Eruca sativa L.), ‘Red Russian’ kale [Brassica napus L. subsp. napus var. pabularia (DC.) Alef.], ‘Mizuna’ mustard (Brassica juncea L.), and red cabbage (Brassica oleracea L. var. capitata f. rubra) microgreens following cultivation under LEDs supplying varying proportions of blue light (5% to 30%) and red light (70% to 95%). Varying the proportion of blue light did not affect the extractable levels of total chlorophyll, total carotenoids, or nitrate in all four microgreen species. Generally, the levels of reduced and total ascorbate were greatest in arugula, kale, and mustard microgreens at 20% blue light, and a minor decrease was apparent at 30% blue light. These metabolite profiles were not impacted by the blue light percentage in red cabbage. Kale and mustard accumulated more total phenolics at 30% blue light than all other blue light regimens; however, this phytochemical attribute was unaffected in arugula and red cabbage. The total anthocyanin concentration increased proportionally with the percentage of supplied blue light up to 30% in all microgreens, with the exception of mustard. Our research showed that 20% blue light supplied from LED arrays is ideal for achieving optimal levels of both reduced and total ascorbate in all microgreens except red cabbage, and that 30% blue light promotes the greatest accumulation of total anthocyanin in indoor-grown Brassicaceae microgreens, with the exception of mustard.

scholarly journals The Effect of Different Doses of Blue Light on the Biometric Traits and Photosynthesis of Dill Plants

2016 ◽  
Vol 44 (1) ◽  
pp. 34-40
Author(s):  
Barbara FRĄSZCZAK
Keyword(s):  
Blue Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Dry Weight ◽  
Simple Relationship ◽  
Light Emitting ◽  
Weight Yield ◽  
Physiological Indexes ◽  
First Time ◽  
Different Doses

The supplementation of blue light to red light enhanced plant growth compared with the use of red alone. The aim of thestudy was to determine the effect of different doses of blue light on the biometric traits and photosynthesis of dill plants. Theplants were grown in pots in a growth chamber. They were grown in red light (100 μmol m-2 s-1) and blue light (from 10 to 50μmol m-2 s-1) in five combinations. Light emitting diode modules were the source of light. The plants were evaluated every 7days during vegetation, for the first time - seven days after germination and later on the 14th, 21st and 28th day aftergermination. The share of blue light in the spectrum significantly influenced the biometric traits of the dill plants. Itsignificantly inhibited the elongation growth of the plants and negatively affected the increase in fresh weight. A small dose ofblue light (20%) had positive effect on the plants’ area. The research did not reveal a simple relationship between the amountof blue light and dry weight yield. The value of physiological indexes depended both on the combination and measurementtime. The plants from the combination with 30% blue light were characterised by the greatest photosynthesis intensity. Aneffective share of blue light in the spectrum may range from 10 to 30% in relation to red light and depends on the plant’sdevelopment phase and on the result we want to achieve in the cultivation of plants.

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