Yellow LED Research Articles

Analysis of Wireless Fire Detector Application to Detect Peat land Fire Based on Temperature Characteristic

Fires of land and forest happened in Riau, give negative impacts to people and its environment. This research discusses about analysis of Wireless Fire Detector as Early Warning System of Peat-land Fire using LM35 Temperature-Sensor, Transmitter-Module(HC-12), Receiver-Module(HC-12), Arduino-ProMini, to produce outputs on LED, LCD, Buzzer. Peat-land fire Detector works when peat land is burning, so its heat spreads through aluminum stem. This temperature is read by Temperature-Sensor1-Temperature-Sensor4. Output of every sensor is sent to each Transmitter-Module(FU1–FU4) in Arduino-ProMini control block. After that, Transmitter-Modules(FU1–FU4) send the readings of sensor to Receiver-Module(FU5). In one time, only one data is received by Receiver-Module from Transmitter-Module. Then, it goes to Arduino-ProMini and processed to get outputs on LCD that display ID of FU1–FU4, Peat-land Status by three activated LEDs, Peat-land temperature. If Green LED is active, means Peat-land not burned. Its temperature is 0°C–21.9°C. LCD displays of SAFE Condition, Buzzer OFF. If Yellow LED is ON, means Peat-land burned underground. Its temperature is 22°C–28.4°C. LCD shows BE-CAREFUL Condition, Buzzer ON. If Red LED is active, means Peat-land burned on the ground. Its temperature is 28.5°C–50°C. LCD displays DANGER Condition, Buzzer ON. This equipment works as its framework.

Analysis on the Optical Response of Ldr and Phototransistor in Photoplethysmography

In photoplethysmography, light source and light detector are employed such that the received signal corresponds to a particular information needed. This research used five different LEDs as light sources. Phototransistor and LDR, on the other hand, were used as light detectors to assess the photosensitivity of human skin. Backscatter simulation was used to compare the photoplethysmographic detection of LDR and phototransistor. The aims of this study include: determine the optical response of a human skin, particularly the skin on the dorsal and palmar parts of the hand; conduct simultaneous simulation using modular and backscattered setup; provide measured value based on the conducted simulations. In every LED color and for both light detectors, ten test conditions were performed, namely: (1) room light on; (2) room light off; (3) room light on - black paper; (4) room light off - black paper; (5) room light on - white paper; (6) room light off – white paper; (7) room light on – dorsal skin; (8) room light off – dorsal skin; (9) room light on – palmar skin; and (10) room light off – palmar skin. Two different simulations were conducted involving all test conditions. The second simulation used light meter which showed similarity in behaviour of obtained values vis-à-vis barcode meter and ADC voltage. The modular involved a lux sensor which checked the findings on the reflectivity of skin Types III and IV of the Fitzpatrick scale and melanocytic naevi skin. The series of simulations conducted proved that the yellow LED provided highest sensor response and phototransistor greater sensitivity than LDR in detecting the received signals. Room light off condition was necessary to reduce the effects of ambient light.

Effects of light quality and photoperiod on growth and photosynthetic pigment content of a Rhodophyta, Gloiopeltis furcata

The objective of the present study was to determine the optimal incubation conditions for Gloiopeltis furcata culture. Three experiments, each lasting 30 days, were conducted to study the effects of photoperiod (6:18, 8:16, 12:12, 14:10, and 16:8 h light/dark), different wavelengths of LED light (blue, green, yellow, red, and white), and solar radiation filtered through different plastic films (blue, green, yellow, red, and white) on the growth and photosynthetic pigment content of G. furcata. The results of these experiments demonstrated that the growth rate of G. furcata was significantly higher under 14:10 and 16:8 light/dark than under 6:18 and 8:16 light/dark, while the pigment content of G. furcata was significant higher under 6:18 and 8:16 than under 14:10 and 16:8 light/dark. The growth rate of G. furcata was the lowest when the algae were exposed to blue LED and the highest under yellow LED illumination, while the phycobiliprotein content was the highest under blue LED and the lowest under yellow LED. Solar radiation filtered through different plastic films had no significant effect on the growth rate of G. furcata, but affected its pigment content. The results indicate that a photoperiod of 12 h or more of light and yellow LED are the optimal parameters for culturing of G. furcata thalli on land.

Synthesis of Co(CO3)0.5(OH)/Ni2(CO3)(OH)2 nanobelts and their application in flexible all-solid-state asymmetric supercapacitor

Design and synthesis of flexible electrode materials with high specific capacitance and rate capability is critical to supercapacitors. In this work, Co(CO3)0.5(OH)/Ni2(CO3)(OH)2 nanobelts with controllable size were successfully synthesized for the first time in the presence of appropriate amount ammonia. And we found that by adjusting the amount of ammonia, the size, morphology and phase composition proportion of Co(CO3)0.5(OH)/Ni2(CO3)(OH)2 could also be controlled. Impressively, benefiting from its special structure and large specific surface area (191.3 m2 g−1), the obtained nanobelts exhibited superior supercapacitor performance with the specific capacitance of 987 F g−1 at 1 A g−1 and 720 F g−1 at 30 A g−1, and an excellent rate performance. The all-solid-state asymmetric supercapacitor (ASC) assembled by using Co(CO3)0.5(OH)/Ni2(CO3)(OH)2 nanobelts as positive materials showed a high specific capacitance of 110.3 F g−1 at 1 A g−1 and 83.3% retention after 5000 cycles, which could provide an energy density of 22.7 Wh kg−1 at a power density of 24019 W kg−1, demonstrating a powerful energy storage capability at high power density for ASC. Moreover, the assembled ASC exhibited an outstanding flexibility, and its supercapacitor properties hardly changed after undergoing the different bending angles. In addition, the two ASCs in series could illuminate a yellow LED for 15 min. These results indicated that the Co(CO3)0.5(OH)/Ni2(CO3)(OH)2 nanobelts had great potential application prospects as a high power density all-solid-state flexible asymmetric supercapacitor electrode materials.

Exposure to blue LED light before the onset of darkness under a long-day photoperiod alters melatonin secretion, feeding behaviour and growth in female dairy calves.

The effect of blue LED on melatonin secretion, feeding behaviour and growth was addressed in Holstein female dairy calves. In Exp.1, six animals (8weeks old, 97±4.1kg BW) were exposed to yellow or blue LED for 2hr before darkness over 7days under a long-day photoperiod (LDPP). In Exp. 2, six animals (8weeks old, 88.5±4.8kg BW) were exposed to blue light from a white LED all daytime or a yellow LED for 2hr before the darkness of LDPP (blue light cut) over 3weeks. In Exp. 1, blue light mildly suppressed melatonin secretion during the 2-hr treatment but did not affect the timing of the nightly melatonin rise. However, the rise in nighty melatonin levels was higher with yellow than blue LED. In Exp. 2, white LED completely suppressed melatonin secretion during the 2-hr treatment, but plasma melatonin concentrations were similar during the darkness. Grass hay intake, rumination time, frequency of water intake and body weight gain were higher in animals exposed to the yellow rather than the white LED. Overall results indicate that exposure to blue light from white LEDs under an LDPP suppresses melatonin secretion and might negatively impact the development of female dairy calves.

Harmful Algal Blooms Associated with Volcanic Eruptions in Indonesia and Philippines for Korean Fishery Damage

Harmful Algal Blooms (HAB) were analyzed to trace the outbreak of dinoflagellate Cochlonidium polykrikoides on the Korean coast from 1993 to 2019 along with relationship to volcanic eruptions. Parameters associated with blooms and fishery damage were sunspot number, El Niño/La Niña events, Kuroshio Current, and volcanic eruptions in the South China Sea including Indonesia and the Philippines. HAB development was halted in seawater due to the sulfur compounds (H2S, SO2, sulfates) from volcanic eruptions inducing the deficiency of the dissolved iron (Fe) in the seawater. Cochlonidium polykrikoides blooms could be predicted by the minimal sunspot number during La Niña event or weak volcanic eruptions in Indonesia and the Philippines. On line monitoring of HAB was suggested using a prototype detector of Cochlonidium polykrikoides at wavelength of 300 nm with the concentration linearity (R2 = 0.9972) between 1000 and 6000 cells/ml. HABs on the Korean coast were negligible when there were volcanic eruptions in either Indonesia or Philippines from May to August. Fishery damage was linearly proportional (R2 = 0.2986) to the maximal concentration of HAB while 5000 cells/ml was the minimal concentration of HAB with high linearity (R2 = 0.7629), caused by old cysts of Cochlonidium polykrikoides on the Korean coast rather than the fresh ones carried by the Kuroshio Current from the Philippines. Fishery damage was reversely proportional to the number of sunspots; the maximal number of sunspots induced frequent volcanic eruption in Indonesia and the Philippines for retardation of HAB with less fishery damage in Korea while the minimal number of sunspots caused less volcanic eruptions for thereby enhancing HAB resulting in more fishery damage. It was proposed that a yellow LED be used at 590 nm as a photochemical expellent as well as H2S gas bubbling at a 0.5 meter depth on the surface of the fish cage to inactivate chemically Cochlonidium polykrikoides due to the deficiency of essential iron in the seawater. In addition, the physical method of blanketing the cage cloth with smaller pore diameter than that of HAB was used for prevention of Cochlonidium polykrikoides penetrating into the fish cage.

시뮬레이션을 통한 455nm 청색 LED 여기 광원과 형광체 조합에 따른 연색특성 변화 연구

Recently, studies have been performed regarding to various methods of improving color rendering properties of white LEDs by mixing warm white (WW) and cool white (CW) or red (R), green (G), blue (B), and yellow (Y) LED spectra. However, the previous researches have been insufficient in presenting maximum optical characteristics over all correlated color temperature (CCT) ranges or representing recently suggested evaluation methods of color rendering properties. In this paper, color rendering properties including the recent methods at all CCTs will be investigated through simulation combining various kinds of phosphors excited by a 455nm blue LED. For evaluating CRI values, general and special color rendering indices (RSUBa/SUB and RSUB9∼14/SUB), general color quality scale (QSUBa/SUB), fidelity index (RSUBf/SUB), and color gamut (RSUBg/SUB) will be examined and compared by root mean square (RMS) values. 2-phosphor combination with a blue LED resulted in RSUBa/SUB≥95, RSUB1∼14/SUB≥75, and QSUBa/SUB≥90, 3-phosphor in RSUBa/SUB≥98, RSUB1∼14/SUB≥75, and QSUBa/SUB≥97, and 4-phosphor in RSUBa/SUB≥94, RSUB1∼14/SUB≥71, and QSUBa/SUB≥90.

Improvement in efficiency of yellow Light Emitting Diode using InGaN barriers and modified electron injection layer

InGaN based MQW-LEDs (Multiple Quantum Well Light Emitting Diodes) are now the new generation of light sources for displays and general lightening applications. The efficiency of blue InGaN LEDs has been matured very much (>80%), but efficiency of yellow LEDs based on InGaN quantum wells still lags behind. In this paper, we have proposed a new structure for yellow LEDs based on InGaN MQW to increase the efficiency of these LEDs. A simulation approach has been used to model and simulate MQW yellow LED based on InGaN quantum wells by using k.p theory. The simulation results show that the proposed structure provides much better output characteristics than the conventional structure. Using the proposed structure, about 18% increment in internal quantum efficiency (IQE) and a decrease of about 36% in efficiency droop of the yellow LED has been successfully achieved.

Photoredox Decarboxylative C(sp3)-N Coupling of α-Diazoacetates with Alkyl N-Hydroxyphthalimide Esters for Diversified Synthesis of Functionalized N-Alkyl Hydrazones.

Herein we report a metal-free photocatalytic coupling reaction for the synthesis of structurally and functionally diverse N-alkyl hydrazones from α-diazoacetates and N-alkyl hydroxyphthalimide esters. By employing Rose Bengal as a photocatalyst with yellow LEDs irradiation, over 60 N-alkyl hydrazones were synthesized. Fluorescence quenching analysis and deuterium incorporation experiments reveal that Hantzsch ester serves as both an electron donor and proton source for the reaction. This strategy offers a simple retrosynthetic disconnection for conventionally inaccessible C(sp3)-rich N-alkyl hydrazones.

Red Sea corals under Artificial Light Pollution at Night (ALAN) undergo oxidative stress and photosynthetic impairment.

Coral reefs represent the most diverse marine ecosystem on the planet, yet they are undergoing an unprecedented decline due to a combination of increasing global and local stressors. Despite the wealth of research investigating these stressors, Artificial Light Pollution at Night (ALAN) or “ecological light pollution” represents an emerging threat that has received little attention in the context of coral reefs, despite the potential of disrupting the chronobiology, physiology, behavior, and other biological processes of coral reef organisms. Scleractinian corals, the framework builders of coral reefs, depend on lunar illumination cues to synchronize their biological rhythms such as behavior, reproduction and physiology. While, light pollution (POL) may mask and lead de‐synchronization of these biological rhythms process. To reveal if ALAN impacts coral physiology, we have studied two coral species, Acropora eurystoma and Pocillopora damicornis, from the Gulf of Eilat/Aqaba, Red Sea, which is undergoing urban development that has led to severe POL at night. Our two experimental design data revealed that corals exposed to ALAN face an oxidative stress condition, show lower photosynthesis performances measured by electron transport rate (ETR), as well as changes in chlorophyll and algae density parameters. Testing different lights such as Blue LED and White LED spectrum showed more extreme impact in comparison to Yellow LEDs on coral physiology. The finding of this work sheds light on the emerging threat of POL and the impacts on the biology and ecology of Scleractinian corals, and will help to formulate specific management implementations to mitigate its potentially harmful impacts.

Curcuminoid-Based Difluoroboron Dyes as High-Performance Photosensitizers in Long-Wavelength (Yellow and Red) Cationic Photopolymerization.

Difluoroboron β-diketonate dyes are reported to exhibit excellent photophysical properties (e.g., broad absorption and large extinction coefficients) and have the potential to act as high-performance photosensitizers in cationic photopolymerization (CP). In this study, four curcuminoid-based difluoroboron dyes (BF2 Curs) are prepared. Their ability to initiate the CP of epoxides or vinyl ethers in combination with an iodonium salt under yellow and red LEDs is investigated. Some of the BF2 Curs-based photoinitiating systems exhibit much higher efficiencies than the reported anthraquinone derivative Oil Blue N (OBN). The molecular structure of BF2 Curs is found to play a critical role in the photoinitiating efficiencies of cationic polymerization.

LumReader: Designing your luminescence experiment with R

During the last decades, luminescence dating has entered a phase of diversification. This evolution is strongly linked to a series of technical advances, including but not limited to the improvement of EMCCD cameras and the use of violet and yellow LEDs. New measurement techniques have been developed, such as post infra-red infra-red stimulated luminescence (postIR-IRSL) measurement protocols and thermally-transferred OSL (TT-OSL), and the luminescence properties of new materials, such as gypsum and apatite, have been reinvestigated.The appropriate configuration of detection equipment is key to the design of new experimental investigations. The R-package LumReader has been designed to simulate both the detection properties of luminescence readers and the emission properties of materials. It allows optimisation of the experimental detection window for a given filter and detector (PMT or EMCCD camera) combination through comparison of the detection window, the stimulation signal and the luminescence emission of the studied material. With the development of a reference database and its flexibility for accommodating user defined functions, this package will allow the spectral information of any luminescence experiment to be simulated, also facilitating experimental design.

Spectral changes associated with transmission of OLED emission through human skin

A recent and emerging application of organic light emitting diodes (OLEDs) is in wearable technologies as they are flexible, stretchable and have uniform illumination over a large area. In such applications, transmission of OLED emission through skin is an important part and therefore, understanding spectral changes associated with transmission of OLED emission through human skin is crucial. Here, we report results on transmission of OLED emission through human skin samples for yellow and red emitting OLEDs. We found that the intensity of transmitted light varies depending on the site from where the skin samples are taken. Additionally, we show that the amount of transmitted light reduces by ~ 35–40% when edge emissions from the OLEDs are blocked by a mask exposing only the light emitting area of the OLED. Further, the emission/electroluminescence spectra of the OLEDs widen significantly upon passing through skin and the full width at half maximum increases by >20 nm and >15 nm for yellow and red OLEDs, respectively. For comparison, emission profile and intensities of transmitted light for yellow and red inorganic LEDs are also presented. Our results are highly relevant for the rapidly expanding area of non-invasive wearable technologies that use organic optoelectronic devices for sensing.

Implication of Melanopsin and Trigeminal Neural Pathways in Blue Light Photosensitivity in vivo.

Photophobia may arise from various causes and frequently accompanies numerous ocular diseases. In modern highly illuminated world, complaints about greater photosensitivity to blue light increasingly appear. However, the pathophysiology of photophobia is still debated. In the present work, we investigated in vivo the role of various neural pathways potentially implicated in blue-light aversion. Moreover, we studied the light-induced neuroinflammatory processes on the ocular surface and in the trigeminal pathways. Adult male C57BL/6J mice were exposed either to blue (400–500 nm) or to yellow (530–710 nm) LED light (3 h, 6 mW/cm2). Photosensitivity was measured as the time spent in dark or illuminated parts of the cage. Pharmacological treatments were applied: topical instillation of atropine, pilocarpine or oxybuprocaine, intravitreal injection of lidocaine, norepinephrine or “blocker” of the visual photoreceptor transmission, and intraperitoneal injection of a melanopsin antagonist. Clinical evaluations (ocular surface state, corneal mechanical sensitivity and tear quantity) were performed directly after exposure to light and after 3 days of recovery in standard light conditions. Trigeminal ganglia (TGs), brainstems and retinas were dissected out and conditioned for analyses. Mice demonstrated strong aversion to blue but not to yellow light. The only drug that significantly decreased the blue-light aversion was the intraperitoneally injected melanopsin antagonist. After blue-light exposure, dry-eye-related inflammatory signs were observed, notably after 3 days of recovery. In the retina, we observed the increased immunoreactivity for GFAP, ATF3, and Iba1; these data were corroborated by RT-qPCR. Moreover, retinal visual and non-visual photopigments distribution was altered. In the trigeminal pathway, we detected the increased mRNA expression of cFOS and ATF3 as well as alterations in cytokines’ levels. Thus, the wavelength-dependent light aversion was mainly mediated by melanopsin-containing cells, most likely in the retina. Other potential pathways of light reception were also discussed. The phototoxic message was transmitted to the trigeminal system, inducing both inflammation at the ocular surface and stress in the retina. Further investigations of retina-TG connections are needed.

Influence of thiourea concentration on the CuS nanostructures and identification of the most suited electrolyte for high energy density supercapacitor

The energy density of a supercapacitor is largely reliant on functional parameters of electrode material and electrolyte. To improve the energy density of the CuS asymmetric device, optimization of sulfur concentration (thiourea) in the precursor and identification of the most suited electrolyte have been attempted. The changes in thiourea concentration greatly affect the physical and electrochemical features of CuS. The highest specific capacitance of 298 F g−1 at 2 A g−1 was obtained for copper sulfide nanoparticles prepared with 1:2 ratio of copper acetate and thiourea (C3). It exhibits excellent cycling stability in 2 M KOH electrolyte. In addition, to evaluate the most suited electrolyte, electrochemical studies were performed with different electrolytes (H2SO4, Na2SO4, KOH and LiClO4 in propylene carbonate). Based on the electrochemical results, it was found that an outstanding performance has originated from H2SO4 electrolyte (773 F g−1 at 2 A g−1). The C3 electrode exhibits no perceptible degradation in capacity even after 4000 charge-discharge cycles in acidic electrolyte. Further, for real-life applications, an asymmetric device was fabricated using C3 as a cathode and PVA/ H2SO4 as electrolyte. The device attained a highest energy density of 21 W h kg−1 at a power density of 310 W kg−1. Furthermore, lighting up of red and yellow LEDs is demonstrated using the fabricated asymmetric device. The efficient device performances concluded that C3 is a potential cathode material for future supercapacitor applications.

Unevenly distributed LED light produces distinct behavioral preferences and production performance of broilers

LED has shown great advantages in poultry husbandry. This study focused on the behavioral preferences and production performance of chicken broilers reared under unevenly distributed yellow LED light. Four pens were divided into two groups adopting respective maximum light intensities (MLIs, 60 lx and 30 lx). Because of different distances from the installation position of the LED pipe, each pen was distributed with unevenly distributed light. Each pen consisted of four subzones indicated by their light intensities-high intensity (HI), medium intensity (MI), low intensity (LI) and weak intensity (WI). Four subzones were the same size and provided with a feeder and a drinker, respectively. The broilers moved freely across the four subzones. No significant differences in body weight (BW), uniformity of final BW and feed conversion ratio (FCR) were observed between the two experimental groups. However, greater feed intake and water intake were found in HI than those in other subzones. The drinking preference changed with age for four subzones and was more likely to appear at the later stage, despite substantial fluctuations within the replicates. The feeding preference was more constant than the drinking preference and appeared mainly at the early and middle stages of this study. These findings could provide implications for broiler production reared under unevenly distributed LED light condition. Keywords: LED, unevenly distributed light, behavioral preference, broiler production performance, light intensity, artificial lighting, animal welfare DOI: 10.25165/j.ijabe.20191202.4689 Citation: Pan C H, Lu M S, Zhang Y P, Yu Y, Lu Q Y, Yang Y F, et al. Unevenly distributed LED light produces distinct behavioral preferences and production performance of broilers. Int J Agric & Biol Eng, 2019; 12(2): 49–53.

Non-destructive evaluation of tomato based on optical scattering.

Equipment for the non-destructive evaluations of a tomato has been developed based on the scattering spectra, the angular distributions of the scattering intensities, and the scattering images from the specimens. The sugar concentrations of tomato can be estimated optically based on the scattering intensities using a halogen lamp, a white light-emitting diode (white LED), a yellow LED, a red LED, and near infrared LEDs (λ = 850 nm and 940 nm) as the incident lights. The scattering intensity is found to vary linearly with sugar concentrations of tomato with any wavelengths at which the scattering light can be observed. The gradient of calibration lines of the sugar concentrations against the scattering intensities varies with scattering angles, θ. Evaluations at around θ = 160° are found to be suitable because of the large gradient and good linearity with the correlation coefficient, R, close to 1.

Non-destructive evaluation of orange juice based on optical scattering intensities

Optical scattering spectra and angular distribution of scattering intensities were evaluated using concentrated orange juice. The concentrated orange juice was opaque due to the scattering particles included. In these specimens, the scattering intensities and angular distribution of the scattering intensities varies with the refractive index ratio of the scattering particles against the liquid surrounding the particles. The sugar concentrations of orange juice, which are linearly correlated with the refractive index of the specimens, can therefore be measured by the scattering intensities and their angular distributions. The scattering intensities measured using a halogen lamp, a white LED, a yellow LED, a red LED and near-infrared LEDs (λ = 850 nm and 940 nm) vary linearly with the sugar concentrations of the specimens. The gradient and correlation coefficient of the calibration lines fitted are found to vary with the scattering angles, θ. A non-destructive evaluation of the sugar concentrations of orange juice can be measured sensitively at θ = 170 or 160 °s with any incident lights which are scattered from the specimens.

異常3 色覚者の錐体基本感度に関する新提案をふまえたある2 型3 色覚者の黄色LED 光の色の見えについての考察

異常3 色覚者の錐体基本感度に関する新提案をふまえたある2 型3 色覚者の黄色LED 光の色の見えについての考察

Efficient InGaN-based yellow-light-emitting diodes

Realization of efficient yellow-light-emitting diodes (LEDs) has always been a challenge in solid-state lighting. Great effort has been made, but only slight advancements have occurred in the past few decades. After comprehensive work on InGaN-based yellow LEDs on Si substrate, we successfully made a breakthrough and pushed the wall-plug efficiency of 565-nm-yellow LEDs to 24.3% at 20 A/cm2 and 33.7% at 3 A/cm2. The success of yellow LEDs can be credited to the improved material quality and reduced compressive strain of InGaN quantum wells by a prestrained layer and substrate, as well as enhanced hole injection by a 3D pn junction with V-pits.