Red Light-emitting Diodes Research Articles

The effect of light emitting diode (LED) spectrum and light duration on growth and yield of Brassica sinensis L. grown on floating raft hydroponic system

Recent technology in agriculture allows vegetable cultivation in controlled environment by utilizing energy derived from an artificial lighting. Light Emitting Diodes (LED) is a source of artificial light which produce light with the wavelength ranged from ultraviolet - 100 nm to infrared - 3,000 nm. Under natural or artificial lighting condition, plants require energy for photosynthesis from light between 380 nm to 700 nm. In this study we examined the use of two types of 45-watt LED (red and blue – C1, full spectrum – C2) with three different light durations (12 h – D1, 16 h – D2, and 18 h – D3) on the growth and yield performance of brassica under hydroponic technique. Research result showed that full spectrum LED provided better performance in plant height, leaves number and width, fresh yield, root length, and biomass in all combinations with light duration as compared to red and blue LED. The combination of full spectrum LEDs with a duration of 16 h showed the best fresh yield (3.96 kg m-2) followed by 18 h (3.57 kg m-2) and 12 h (3.22 kg m-2). Although the highest production was resulted from the combination of full spectrum LED and 16 h light duration, the most efficient in electric energy utilization was showed in the combination of full spectrum LED and 12 h light duration. All in all, we concluded that the use of full spectrum LED in combination with 16 h light duration feasible to be implemented in brassica cultivation under controlled environment.

Application of Red and Blue LED Light on Cultivation and Postharvest of Tomatoes (Solanum lycopersicum L.).

Currently, light-emitting diode (LED) technology has produced a more energy-efficient and versatile technology as an artificial lighting system that can be applied in the agricultural sector. Artificial lighting technology has been proven to be effective in increasing the production of agricultural products, especially horticultural commodities. As one of the primary horticulture commodities, tomatoes are the most common crop produced in controlled environments with LED artificial lighting. The focus of this study is to describe the application of LED lights in tomato cultivation and postharvest. We provide an amalgamation of the recent research achievements on the impact of LED lighting on photosynthesis, vegetative growth, flowering, production, and postharvest of tomatoes. Red-blue (RB) lighting induces photosynthesis; increases the content of chlorophyll a, chlorophyll b, and carotenoids in tomato leaves; regulates vegetative growth in tomatoes; and increases the production of tomatoes. In postharvest tomatoes, blue LED lighting treatment can slowly change the color of the tomato skin to red, maintain hardness, and increase shelf life. Future research may be carried out on the effect of LED artificial lighting on tomatoes' phytochemical, antioxidant and other crucial nutritional content. Different LED wavelengths can be explored to enhance various bioactive compounds and health-promoting components.

A thermally activated delayed fluorescent platinum(ii) complex for red organic light emitting diodes with high efficiencies and small roll-off

A design of Pt(ii)–TADF emitters based on metal-perturbed intraligand charge-transfer excited states towards high-performance red organic light-emitting diodes is presented.

Fully solution-processed red tandem quantum dot light-emitting diodes with an EQE exceeding 35%

By balancing carrier injection and improving charge generation efficiency, the EQE of red tandem QLEDs obtained by all-solution processing exceeds 35%.

Strategic defect control of perovskite nanocrystallites with octylammonium iodide toward efficient red perovskite light-emitting diodes with high operative stability

Octylammonium iodide (OIAI) incorporated into pure-red PeLEDs with high EQE and narrow bandwidth, along with high operative stability.

Frequency Reconfigurable Antenna Design and Analysis with White LED Lamp, Red and Infra-red LEDs

Frequency Reconfigurable Antenna Design and Analysis with White LED Lamp, Red and Infra-red LEDs

Evaluation of broiler performance reared under monochromatic light emitting diode (LED) tubes vis-a-vis incandescent light supplemental lighting

This study was conductedto evaluate the effect of different monochromatic LED lightson the performance of broiler chickens. A total of 120 day-old Lohmann Meat (Indian River) broiler chicks were randomly assigned to three treatment groups: incandescent light (control), red LED light and white LED light, with each group consisting of four replicates of 10 chicks. The chicks exposed to LED lighting showed higher average live weight and liveweight gain compared to the control group, while no significant differences(P>0.05)were observed in feed intake, feed conversion ratio and survivability. Carcass yields, including breast, thigh, drumstick, wing, neck, liver, heart, and spleen, were not significantly affected by the different monochromatic lighting sources (P>0.05). However, significant differences(P˂0.05)in the weights of the back and proventriculus were observed between the white LED group and the other treatment groups. These results suggest that LED lighting could serve as a better alternative to incandescent bulbs in broiler houses, with the potential to enhance broiler performance and carcass yield.

A highly efficient deep red-emitting Mn4+-powered oxyfluoride nanophosphor developed for plant growth and optical thermometric applications.

This research mainly highlighted an intense deep red-emitting and Mn4+-powered oxyfluoride nanophosphor, Mg14Ge4.99O16F8:0.01Mn4+ (MGOF:Mn), which was synthesized via adopting a scalable synthesis route for commercial temperature sensing and artificial plant growth applications. The electron microscopic analysis confirmed the formation of nanosized particles without any defined shape or size distribution. The obtained nanophosphor exhibited sharp emission peaks at 659 nm and 631 nm under UV (317 nm) and blue excitation (417 nm) owing to Mn4+:2Eg → 4A2g and Mn4+:2T1g → 4A2g transitions, respectively. The emission spectrum is situated in the deep red region of the CIE color diagram where the red color purity approached 100% under both the excitations. The absorption efficiency and the internal and external quantum efficiencies of this red-emitting system were calculated to be 53%, ∼77%, and ∼41%, respectively, under blue excitation of 417 nm, which indicated its potential for indoor plant cultivation. A prototype red LED was fabricated by pasting the red-emitting MGOF:Mn4+ nanophosphor powder on a 410 nm blue LED chip. The resulting electroluminescence spectrum overlapped with those of the important organic pigments of normal plants. Importantly, the thermometric properties of the nanophosphor were evaluated in detail for FIR and lifetime-based thermometry applications. The examined nanophosphor showed an extreme absolute sensitivity of 0.00326 K-1 at 373 K with excellent reproducibility and temperature resolution. Because of the small particle size and high luminescence efficiency, the nanophosphor could be implemented in various nano-devices where non-contact optical thermometry is necessary for high performance.

COMPARISON OF THE EFFECTIVENESS OF MYOFASCIAL PAIN REDUCTION USING LOW-INTENSITY LASER AND RED LED LIGHT THERAPY IN PATIENTS WITH TEMPORO¬MANDIBULAR JOINT DYSFUNCTION

Introduction: Today, there is a significant prevalence of temporomandibular joint (TMJ) dysfunction, which currently ranges from 21.5 % to 50.5 %. This disease can worsen the patient's quality of life due to the presence of pain, which is the main symptom of this pathology. To reduce the intensity of pain in patients with TMJ dysfunction, low-level laser and red LED light therapy is used. There are a significant number of studies proving clinical efficacy in alleviating the symptoms of TMJ dysfunction using various methods of light therapy, but the number of studies comparing the effectiveness of different light therapy options among themselves is quite limited. The aim of the study was to compare the effectiveness of pain relief and the number of trigger points in patients with TMJ dysfunction using a low-level laser and red LED light. Materials and methods: 60 patients were randomised into 2 groups. Randomisation for patient allocation was performed using Microsoft Excel 2016. Patients of group I received red LED light therapy, radiation sources were applied to the trigger points of the masticatory muscles extracorporeally for 5 minutes. Patients in group II received low-intensity laser therapy for 30 seconds on the trigger points of the masseter muscles extracorporeally. Patients in both study groups received therapy weekly for 4 weeks. The effectiveness of the treatment was assessed by filling out a visual analogue scale (VAS), the number of trigger points of the masticatory muscles and the force of contraction of the masticatory muscles at rest and during tooth contact in patients with temporomandibular joint dysfunction. Results: the VAS scores in group I decreased by 47.02 % from the start of treatment, in group II – by 53.7 %. The number of trigger points in the projection of the masticatory, temporal muscles and parotid region in group I decreased by 62.34 %, in group II – by 72.21 %. According to electromyography, in group I, the amplitude of bioelectrical impulses of the masticatory muscles at rest decreased by 20.58 % on average, and in the state of voluntary teeth clenching – by 22.89 %. In group II, the amplitude of bioelectrical impulses of the masticatory muscles at rest decreased by 25.58 % on average, and in the state of voluntary teeth clenching – by 28.37 %. Conclusions: red LED light therapy and low-level laser therapy reduces pain intensity and the number of trigger points in patients with myofascial pain. Comparison of the effectiveness of red LED light therapy and laser therapy in reducing pain syndrome showed a higher ability of laser therapy to reduce myofascial pain and the number of trigger points in patients with temporomandibular joint dysfunction (p<0.01).

Effect of light and cytokinin on growth and curculin gene expression of Curculigo latifolia on in vitro culture.

Despite being valuable for producing a natural sweetener Curculin, Curculigo latifolia has a low growth and difficult to domestificate. So, to solve this problem, propagation on in vitro culture will be an alternative method to propagated this spesies under different cytokinins and light condition. Cytokinins and light has major role in organogenesis, growth and gene expression of many species. Thus, in this study, we aimed to improve the Curculigo latifolia growth on in vitro condition and expression of curculin gene by combining cytokinins addition and different light exposure. Four weeks seedlings were sub-cultured into medium (MS free hormone) containing 3 mg/L benzyladenine (BA) and various concentrations of meta-Topolin (mT) including 0.1 mg/L, 0.5 mg/L, and 5 mg/L. The cultures then incubated under different light types (red, blue, white LED lights and white fluorescence light) with 16-h light/ 18-h dark photoperiod for 14 weeks at 25 ± 2°C. Several parameters, including plant height, leaf number, chlorophyll contents, stomatal structure, and density and curculin expression, were observed every week. Unexpectedly, our results showed that C. latifolia growth displayed significant improvement when it was treated under white LED light without any additional cytokinins. In sum, white LED light further improves plantlets phenotype, such as plant height, leaf number, chlorophyll production, and stomatal number and structure, whereas, red LED light lead to a decreased phenotypes but increase the curculin gene expression.

Peanut Oil Cake Biomass‐Derived Hierarchical Porous Carbon by Dual Step Activation as Potential Electrodes for Fabrication of Prototype Symmetric Supercapacitor Device

Peanut oil cake biomass is a major by‐product of oil industry and can be a suitable precursor for the production of biomass‐based porous carbon. Herein, dual‐stage activation, physical activation at 400°C, and chemical activation using KOH between 600 and 900°C are adopted to prepare hierarchical porous carbons (HPCs) from peanut oil cake biomass for use as electrode material in electrochemical supercapacitors. The textural and structural properties of the HPC were evaluated by N2‐adsorption/desorption, X‐ray diffraction, Raman, FT‐IR spectroscopy, and scanning electron microscopy. The prepared HPC inherited sufficient micropores and mesopores distribution with a maximum BET surface area of 640 m2/g. The electrochemical properties of the HPC electrodes were evaluated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopic analysis. Among different HPC electrodes prepared, the carbon prepared at 800°C (HPC‐P8) electrode material exhibited a high specific capacitance of 187 F/g at 0.5 A/g in 1M Na2SO4 electrolyte in three‐electrode systems. Symmetric supercapacitors were also fabricated using HPC‐P8//HPC‐P8 as positive and negative electrodes using 1M Na2SO4 electrolyte, in a two‐electrode cell configuration via split cell method. Maximum specific capacitance of 30 F/g was achieved with superior cycle stability of 93.8% capacitance retention over 5,000 cycles for the symmetric device. The device operated at a wide potential window (0–2.0 V) resulted in appreciable specific energy and power density of 15.89 Wh/kg and 493 W/kg, respectively. HPC‐P8 had an ion diffusion coefficient of 7.79 × 10−8 cm2/s which is higher than the other prepared carbon samples. The symmetric device showed relatively high charge storage capacity and cyclic stability without any material degradation. The fabricated prototype portable supercapacitor module was tested for red LED glow with maximum intensity brightness up to 4 min. Thus, the present study reveals that HPC derived from peanut oil cake biomass can behave as a promising electrode material for supercapacitor applications.

Polypyrrole and activated carbon enriched MnCo2O4 ternary composite as efficient electrode material for hybrid supercapacitors.

The development of proficient electrode materials is one of the major tasks faced by modern techniques for energy storage. Integrating different materials with synergistic effects can be a valuable strategy for designing storage devices with high capacity and energy density. The spinel manganese cobaltite (MnCo2O4) is an outstanding candidate for supercapacitors owing to its remarkable pseudocapacitive behavior. However, it suffers from low electric conductivity and limited cyclic stability. To overcome its limitations, activated carbon with superior cyclic stability and polypyrrole with high electric conductivity can be incorporated in MnCo2O4. The synergistic effect of these components offers high capacitance, better conductivity, and superior cyclic performance to the ternary composite. Herein, the MnCo2O4/AC/PPY ternary composite has been synthesized by a facile approach. The optimized ternary composite (MAP-20) exhibited a wonderful capacitance of 945.77 F g-1 at five mV s-1 compared to pristine MnCo2O4 (254.98 F g-1). The real-time applicability of the optimized composite was tested with asymmetric device configuration. The asymmetric device with MAP-20 and MnO2/AC electrodes exhibited a wonderful Ed of 88.12 W h kg-1 (Pd ∼ 1.6 kW kg-1). The asymmetric device also exhibited excellent cyclic performance of 89.68% for 10 000 cycles. Further, the real-time applicability of the device was tested by illuminating a 39 red LED panel. Three asymmetric cells connected in series illuminated the panel for about 45 minutes. All these results suggest that the synergistic integration of various efficient electrode materials leads to enhanced electrochemical performance of supercapacitors.

Periodic and Local LED Light Switching Induces Broiler Locomotion.

Wooden breast myopathy and leg weakness are serious problems in the broiler chicken industry. The color and intensity of light in the chicken habitat affect behavior, including walking of chicks. The present study was conducted to determine whether periodic and local light switching induces locomotion and affects wooden breast myopathy and leg weakness in broiler chicks. Thirty five-day-old broiler chicks were assigned to two pens (4.72 m × 0.73 m each). In the control pen, chicks were reared under three white-light emitting diode (LED) lights until they were 42 days old. In the other pen, chicks were reared under a white LED light located in the center, supplemented with blue or red LED lights on either side of the pen. The color of the LED lights changed every 3 h, from blue and red to red and blue. From 21 d of age, all LED lights were changed and only one of the side lights was turned on every 3 h. From 35 d of age, all three white lights were turned on until 42 d of age. Periodic and local color switching and on-off switching significantly induced locomotion in broiler chicks. Wooden breast scores tended to improve with light-switching treatment. The tibia length, diameter, and breaking strength were not significantly affected. This is the first report showing that locomotion may be induced in broiler chicks by periodic and local lighting switching, and may be useful for improving the health status of broiler chicks.

A day-night solar thermoelectric generator enabled by phase change material and forced water cooling

Solar thermoelectric generators (STEGs), which are capable of directly converting solar energy to electricity, are essential to many potential applications in addition to photovoltaics. It is of great importance to advance the design of STEGs to significantly boost the output performance by combining solar selective absorbers, cooling technologies and phase change materials. In this work, a novel day-night STEG integrated with transparent phase change materials of methyl palmitate and forced water cooling (PCM-STEG-WC) is proposed. The fabricated solar selective absorber exhibits a high solar absorption of 96.05 %, leading to its surface temperature up to 100 °C under 1-sun illumination (1 kW m−2), while the surface temperature of conventional thermoelectric module is only about 44.4 °C. Consequently, the temperature difference between hot and cold ends can be significantly increased to 5.6 °C from 2 °C, about 2.8 times higher than the conventional thermoelectric module. Moreover, this unconcentrated PCM-STEG-WC can realize a power level of 6.42 mW associated with output voltage of 307.3 mV at a solar density of 1 kW m−2, which is about 9 times higher than that of conventional thermoelectric module (35.5 mV). Additionally, the hot end temperature of PCM-STEG-WC only decays by 17 % in 100 s without solar radiation. To demonstrate the effectiveness of the PCM-STEG-WC in power generation at night, a single red LED is completely powered. Finally, this study may provide a promising strategy to develop high-performance STEGs for remote applications.

Redox additive effects on the electrochemical performance of hydrothermally grown, binder-free CuO nanosheets in aqueous electrolytes

Adding redox additives into the traditional electrolytes is an efficient approach to achieving high-performance binary metal oxide electrode-based supercapacitors (SCs). Herein, binder-free CuO nanosheets are developed on nickel foams via a facile hydrothermal approach, and their charge storage performance in K3[Fe(CN)6] (KFCN) redox additive electrolyte is investigated. In a three-terminal (3T) configuration, the as-prepared electrode demonstrates a remarkable capacitance of 2755 mF cm−2 (2296 F g−1) in KFCN redox additive electrolyte, which is 10 times greater than that obtained in bare KOH electrolyte (266 mF cm−2 or 222 F g−1). Further, the 93 % capacitance retention after 2000 cyclic voltammetry cycles confirms the reasonable stability of the CuO electrode for SCs with redox additives electrolyte. Additionally, the assembled CuO electrodes-based solid state symmetric supercapacitor (SSC) with redox additive gel electrolyte achieves a maximum energy density (Es) of 31.5 Wh kg−1 at a power density (Ps) of 500 W kg−1. Furthermore, red LEDs are operated by the power source of two SSCs connected in the serial mode for 130 sec. This studies imply that utilizing CuO within redox additive electrolytes could present a simple and cost-effective approach for developing high-energy storage supercapacitors.

Effects of Auditory Cue Length and Visual Cue Superimposition on Gait Initiation in Parkinson’s Disease: A Pilot Study

Objectives: Effects of cues on gait disturbance in Parkinson’s disease (PD) depend on features of cue presentation. We investigated the effects of the length of simple auditory cues on cue-triggered gait initiation in PD. Methods: The subjects were 8 PD patients in OFF-state (6 women and two men, aged 50-75 years) and 8 normal controls (NCs) (5 women and three men, aged 55-77 years). For the assessment of gait initiation, the subjects were instructed to take three steps without the strong constraint of a quick start. The auditory cues consisted of long and short beeps, and the visual cue was a red light-emitting diode (LED) line projected across the floor 15 cm in front of the subjects’ toes. The four experimental conditions were: (1) short Beep condition (0.1 sec), (2) long Beep condition (3 sec), (3) short Beep/LED condition and (4) long Beep/LED condition. Results: The gait initiation time was delayed, and the initial step length was short under the Beep conditions in the PD patients compared with those in the NCs. Neither parameter differed between the short Beep and the long Beep conditions. Superimposition of the visual cues improved the gait initiation time under the short Beep condition and the initial step length under the short and long Beep conditions. Conclusion: The duration of single auditory cues does not contribute to the gait initiation time and initial step length in PD. Although large-sized studies are necessary to confirm the results, instantaneous auditory perception may be the primary driving force for the effects of single auditory cues on gait initiation.

Demonstration of 82% relaxed In0.18Ga0.82N on porous GaN pseudo-substrate by plasma-assisted molecular beam epitaxy

In this study, the impact of InGaN film thickness and different compositionally graded structures on InGaN relaxation grown on tiled GaN-on-porous-GaN pseudo substrates (PSs) were studied. In addition, the impact of the degree of porosification on the In incorporation and relaxation of InGaN were examined. 82% relaxed 1μm thick In0.18Ga0.82N, which is equivalent to a fully relaxed In-composition of 15%, on porous GaN PS was obtained. Additionally, multi-quantum wells (MQWs) grown on the MBE InGaN-on-porous GaN base layers by MOCVD showed ∼85 nm redshift in comparison with MQWs grown on planar GaN. The developed InGaN-on-porous-GaN PSs can provide an alternative route to grow MQW with a high In content which is essential for high-efficiency nitride-based red LEDs.

A comparative study on porous activated carbon derived from waste biomass with varying oxygen functionalities as supercapacitor electrodes

AbstractActivated carbon derived from biomasses with different oxygen‐bearing chemical constituents has been explored as supercapacitor electrode. The rice straw (RS) and eucalyptus wood biomasses were selected owing to their contrasting composition of cellulose, hemicellulose, and lignin contents. The activated carbons of these biomasses are obtained by pyrolysis at 550°C followed by thermal activation (700°C) after treatment with optimized KOH. The specific capacitance of RS‐based activated carbon (ACRS‐700), measured from galvanostatic charging‐discharging studies at 0.5 A g−1, is much higher (eg, 365 F g−1) than that of ACEW‐700 (168 F g−1). The higher specific capacitance of ACRS‐700 is attributable to: (i) significantly higher surface area (3345 m2 g−1) comprising of interconnected micro‐ and mesoporous structure; (ii) porosity of about 2.0 cm3/g; and (iii) oxygen‐rich hemicellulose contents. The possible charge storage mechanism in ACRS‐700 has been discussed. The real‐time application of ACRS‐700 has been demonstrated by lighting up red LEDs using ACRS‐700//ACRS‐700 symmetric supercapacitor device, operated with aqueous and freshly synthesized [Bu4N+][NO3−] ionic liquid as electrolytes. The maximum energy density (42.7 Wh kg−1) and the power density (1.9 kW kg−1) for ionic liquid electrolyte are favourable for supercapacitor applications.

Holştayn İneklerde Kırmızı Işıkla Gece Aydınlatmasının Melatonin ve Süt Kalite Parametrelerine Etkileri

In this study, it was aimed to investigate the effects of red lighting on blood and milk melatonin levels, and milk quality. The experiment was carried out on 6 lactating Holstein Dairy cows, which were being reared at the Hümeyra Özgen Research and Application Farm, affiliated to Selcuk University Faculty of Veterinary Medicine. After a control period of 15 days in which night lighting was not applied (control group), night lighting was provided by LED bulbs emitting red light with a wavelength of 652 nm during the following 15-day trial period (experimental group). On days 5th, 10th and 15th days of the control and experimental groups, milk and blood samples were taken at the 06:00 am and at 06:00 pm.Serum and milk melatonin concentrations in the morning of the control, on days 5th, 10th and 15th; were 8.64±1.4, 7.02±0.97, 8.71±2.3, and 5.01±0.92, 5.23±0.35 , 3.93±0.81pg/ml, respectively while control evening group were respectively 8.59±1.8,7.53±2.14,8.35±0.94, 6.91±1.73, 6.8±1.27. It was obtained as 3.67±0.97 pg/ml. Serum and milk melatonin levels in the trial morning group were 10.93±2.06, respectively, on the same days; 15.37±2.6; 11.25±1.71 and 2.97±0.64; 5.7±1.06; While it was measured as 3.33±0.73 pg/ml, it was 14.83±3.11 in the trial evening group; 14.5±3.57; 12.95±4.09 and 4.42±0.61; 2.51±0.56; It was obtained as 2.48±0.79 pg/ml.It was observed that serum and milk melatonin levels and milk parameters were not adversely affected in the use of red LED lamps (652 nm) at night for 12h.

Designing Prototype of Volume Detector for Medical Oxygen Cylinder Using NodeMCU ESP8266

The COVID-19 pandemic posed significant challenges to the healthcare sector, particularly due to the imbalance between patient numbers and available medical staff, resulting in difficulties during emergencies. One such challenge was the prompt replacement of oxygen cylinders. Leveraging Internet of Things (IoT) technology, we developed a prototype oxygen cylinder volume detector aimed at providing early notifications to healthcare professionals. This prototype incorporates the NodeMCU ESP8266, equipped with an Infrared (IR) Obstacle Sensor. The sensor communicates with a relay to activate an MP3 module, delivering audible alerts. Furthermore, the NodeMCU ESP8266 system integrates CTBot to send text notifications through the Telegram application to the nearest healthcare personnel. Visual alerts are also provided through red LED lights attached to the cylinders, indicating which oxygen cylinder is approaching depletion. Comprehensive testing validated the proper functionality of all system components. This innovative oxygen cylinder detector prototype is designed to streamline healthcare worker and nurse workflows by offering quicker access to accurate information regarding the status of medical oxygen cylinders. Not only does this enhance patient care efficiency, but it also ensuring the availability of oxygen is crucial for critical patients.