scholarly journals Photosynthetic efficiency, growth and secondary metabolism of common buckwheat (Fagopyrum esculentum Moench) in different controlled-environment production systems

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Marta Hornyák ◽  
Michał Dziurka ◽  
Monika Kula-Maximenko ◽  
Jakub Pastuszak ◽  
Anna Szczerba ◽  
...  
Keyword(s):  
Secondary Metabolism ◽  
Production Systems ◽  
Soluble Carbohydrates ◽  
Controlled Environment ◽  
Light Sources ◽  
Common Buckwheat ◽  
Light Emitting ◽  
Led Light ◽  
Plant Cultivation ◽  
Fagopyrum Esculentum Moench

AbstractLight-emitting diodes (LEDs) and high-pressure sodium lamps (HPS) are among the most commonly used light sources for plant cultivation. The objective of this study was to evaluate the effect of two controlled-environment production systems differing in light sources on growth, photosynthetic activity, and secondary metabolism of common buckwheat. We hypothesized that LED light with the majority of red and blue waves would increase physiological and biochemical parameters compared to sunlight supplemented with HPS lamps. The experiment was performed in a phytotronic chamber (LEDs) and in a greenhouse (solar radiation supplemented with HPS lamps as a control). The effects were analyzed at the flowering phase with biometric measurements, leaf chlorophyll index, the kinetics of chlorophyll a fluorescence, content of soluble carbohydrates and phenolics in the leaves. Applied LED light decreased the biomass but stimulated the production of phenolics compared to control plants. In control plants, a positive correlation between flavonoid content and energy dissipation from photosystem II (DIo/CSm) was found, while in plants under LEDs total pool of phenolic content correlated with this parameter and the quantum yield of electron transport (φ Ro and ψ Ro) was lower than that of the control, probably affecting buckwheat biomass.

scholarly journals A Practical Method to Design Reflector-Based Light-Emitting Diode Luminaire for General Lighting

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Jinren Yan
Keyword(s):  
Light Emitting Diode ◽  
Spherical Surface ◽  
Target Surface ◽  
Practical Method ◽  
Optical Simulation ◽  
Light Sources ◽  
Aspheric Surface ◽  
Light Emitting ◽  
Led Light ◽  
Spherical Reflector

A reflector-based light-emitting diode (LED) luminaire structure that can achieve a large cut-off angle for general lighting is presented in this work. The proposed lighting unit mainly consists of a spherical reflector and a primary packaging lens that contains an aspheric surface and a spherical surface. The light rays emitted from the LED light source are well controlled by the spherical reflector and the aspheric surface of the lens for the purpose of obtaining a uniform illumination on the target surface. Both the ideal Lambertian LED and non-Lambertian LED light sources were employed to validate the proposed structure and the performance of the designed lighting units was analyzed by optical simulation. The results show that the light utilization efficiencies and the estimated uniformities are 92.96% and 91.11% for ideal Lambertian LED-based lighting unit and 93.31% and 91.64% for non-Lambertian LED-based lighting unit, respectively. Further analysis shows that the tolerances of horizontal, vertical, and rotational deviation of the both lighting units were about 2.0 mm, 1.0 mm, and 1.0°, respectively.

Responses of Favorita Potato Plantlets Cultured in Vitro under Fluorescent and Light-Emitting Diode (LED) Light Sources

2019 ◽  
Vol 96 (4) ◽  
pp. 396-402 ◽  
Author(s):  
Lili Jiang ◽  
Ziquan Wang ◽  
Guanghui Jin ◽  
Dianqiu Lu ◽  
Xuezhan Li
Keyword(s):  
Light Emitting Diode ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Potato Plantlets

scholarly journals Lifetime Prediction method of LED Light-emitting Device Based on Approximate Analysis

2021 ◽  
Vol 271 ◽  
pp. 01031
Author(s):  
Cai Wenting ◽  
Li Sheng ◽  
Meng Qinghui ◽  
Huang Haisong
Keyword(s):  
Approximate Method ◽  
Light Source ◽  
High Efficiency ◽  
Light Flux ◽  
Prediction Method ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Long Life ◽  
Application Requirements

Compared with other light sources, LED light source has a longer service life and will not suddenly fail. Due to its high efficiency, energy saving and long life, LED has become the most popular light source at present. However, it is no longer considered to meet the application requirements, and the time that the light flux decays to this level is considered to be the life of the LED. This paper introduces the approximate method used to predict the lumen maintenance life of LED lamps. The experimental results obtained by the approximate method are compared with the TM-21 standard. Eventually, it is concluded that the approximate method provides more reliability information than the original TM-21 standard, and the obtained results are more reference, more accurate and more reliable.

Radiometric and Spectrophotometric Analysis of Third Generation Light-Emitting Diode (LED) Light-Curing Units

2007 ◽  
Vol 8 (2) ◽  
pp. 43-51 ◽  
Author(s):  
Barry M. Owens ◽  
Kelbin H. Rodriguez
Keyword(s):  
Spectral Distribution ◽  
Light Emitting Diode ◽  
Spectrophotometric Analysis ◽  
Battery Life ◽  
Light Sources ◽  
Third Generation ◽  
Light Emitting ◽  
Led Light ◽  
Restorative Materials ◽  
Light Curing

Abstract Aims Light-emitting diode (LED) polymerization of dental restorative materials has become increasingly popular. However, individual light-curing unit (LCU) functions (intensity and/or wavelength emission) may not conform to manufacturer specifications due to quality control issues. The purpose of this study was to evaluate the quality of irradiance, in terms of power density (intensity) and spectral distribution (peak wavelength), emitted from LED and quartz-tungsten halogen (QTH) LCUs in vitro. The battery expenditure of these LED units was also tested. Methods and Materials The intensity and spectral distribution from four third generation LED (Smartlite PS, Coltolux LED, radii Plus, Diopower) and one QTH (Schein Visible Cure) light sources were measured using six different dental curing light meters (Coltolux, Cure Right, Demetron 100, Demetron LED., Hilux, and Light Meter-200) and a visible-ultraviolet light spectrophotometer (Hitachi Elmer-Perkins). The battery life was also plotted for each light source following a 1500 second duration period. The data obtained from radiometric and spectrophotometric analysis was compared to manufacturer specifications. Results Radiometric evaluation revealed LED light units tested did not satisfy manufacturer claims for minimum intensities. Spectral emissions from the LED light sources did meet manufacturer requirements. No clinically appreciable battery drain was evidenced from testing all re-chargeable LED units. Conclusion Despite limitations LED technology appears to be an effective alternative for curing of lightactivated esthetic restorative materials. Additional advantages associated with LED curing lights include ergonomic handling capabilities, negative heat generation, and minimal maintenance concerns. Citation Owens BM, Rodriguez KH. Radiometric and Spectrophotometric Analysis of Third Generation Light- Emitting Diode (LED) Light-Curing Units. J Contemp Dent Pract 2007 February;(8)2:043-051.

PHOTOTHERAPY FOR MILD TO MODERATE ACNE VULGARIS WITH PORTABLE BLUE AND RED LED

2011 ◽  
Vol 04 (01) ◽  
pp. 45-52 ◽  
Author(s):  
GUANGDA LIU ◽  
CHANGE PAN ◽  
KAI LI ◽  
YUAN TAN ◽  
XUNBIN WEI
Keyword(s):  
Side Effects ◽  
Light Emitting Diode ◽  
Acne Vulgaris ◽  
Red Light ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Led Phototherapy ◽  
Red Led ◽  
Complete Treatment

In this paper, we studied portable blue and red light-emitting-diode (LED) light sources in phototherapy for mild to moderate acne vulgaris to evaluate the efficacy and tolerance of patients. Patients, randomly divided into blue and red groups, received either blue or red LED phototherapy twice a week for four weeks. After complete treatment, the number of lesions reduced by 71.4% in the blue group, in contrast to 19.5% in the red group. No obvious side effects were observed during and one month after the treatment, except for some mild dryness mentioned by several patients.

scholarly journals Determination of the effective operating hours of the intermittent lighting system for growing vegetables

2021 ◽  
Vol 935 (1) ◽  
pp. 012004
Author(s):  
N Kondrateva ◽  
D Filatov ◽  
R Bolshin ◽  
M Krasnolutskaya ◽  
A Shishov ◽  
...  
Keyword(s):  
Operating Time ◽  
Electricity Consumption ◽  
Operating Mode ◽  
Farming System ◽  
Controlled Environment ◽  
Light Sources ◽  
Lighting System ◽  
Light Emitting ◽  
Vertical Farming ◽  
The Cost

Abstract Around the world, one of the key challenges is the provision of food for a growing urbanized population. A vertical farming system will help solve this problem. Vertical farming in a controlled environment provides 4-6 times higher yields per unit area, but requires more electricity. The most economical light sources are light-emitting diodes but it is important to determine the rational operating mode of the lighting system. The aim of the study was to determine the specific operating hours of the intermittent lighting system to reduce the cost of electricity consumption when growing vegetables in vertical farming in a controlled environment. Continuous and periodic modes of operation of the lighting system with a total operating time of 16 hours per day were considered. In Russia, there are six price categories for consumed electricity. Research has shown that price level II is economically viable. and a rational operating mode: 8 hours of light/4 hours of darkness, etc. Thus, the intervals of operation of the lighting system are 11.00-19.00 and 23.00-7.00. The study of this regime for microgreening of Mitsun head cabbage showed that the productivity of the plants was preserved, since the length of the leaves did not change.

scholarly journals Studies Regarding Treatments of Led-s Emitted Light on Sprouting Fagopyrum Esculentum Moench

2017 ◽  
Vol 74 (2) ◽  
pp. 102
Author(s):  
Oana LIVADARIU ◽  
Carmen MAXIMILIAN
Keyword(s):  
Phenolic Compounds ◽  
Antioxidant Capacity ◽  
Light Emitting Diodes ◽  
Fagopyrum Esculentum ◽  
Bioactive Components ◽  
Fresh Weight ◽  
Light Emitting ◽  
Led Light ◽  
Adverse Influence ◽  
Fagopyrum Esculentum Moench

The present study presents the influence exercised by LED (light emitting diodes)-s emitted white (W), red (R), blue (B) light on sprouting of buckwheat seeds and evaluated the effects on content of phenolic compounds, antioxidant capacity and flavonoids.The fresh weight of hypocotyls, showed that the R light has generated the best influence for sprouts and W light has generated the most adverse influence. The content of flavonoids was stimulated by R LED for variant sprouts with testa (V3), while both B and R LED inhibited for variant without testa (V4, V6). The higher concentration of polyphenols was obtained for V5 variant illuminated with B LED and increased for V4 variant illuminated with R LED. The antioxidant capacity was higher for V3 variant illuminated with B light and stimulated by R LED in V4 variant.The results contribute to the establishment an efficient working protocol, for obtaining sprouts from buckwheat seeds, with a comprehensive content of bioactive components, various nutrients by applying the R LED treatment.

A novel Cr3+-doped Lu2CaMg2Si3O12 garnet phosphor with broadband emission for near-infrared applications

2021 ◽  
Author(s):  
Wendong Nie ◽  
Liqin Yao ◽  
Guang Chen ◽  
Shihao Wu ◽  
Zhijian Liao ◽  
...  
Keyword(s):  
Plant Growth ◽  
Environmental Science ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Light Emitting ◽  
Broad Application ◽  
Led Light ◽  
Broadband Emission ◽  
Application Prospects

The near-infrared (NIR) phosphor-converted light emitting diode (pc-LED) light sources have broad application prospects in environmental science, biomedical and plant growth fields. However, NIR phosphor still suffers from narrowband emission...

Evaluation of Color Rendering Index for LED and Fluorescent Light Sources

2015 ◽  
Vol 731 ◽  
pp. 22-26
Author(s):  
Huan Jiang ◽  
Min Huang ◽  
Fu Song Yang ◽  
Yu Liu
Keyword(s):  
Light Emitting Diode ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Led Light ◽  
Color Science ◽  
Color Rendering Index ◽  
Different Color ◽  
Color Rendering

In order to assess the performances of different color rendering index (Ra, CRI, CQS, nCRI, R96a). The LED (light-emitting diode), fluorescent light sources and 30 printed color samples were used in our experiment. 20 observers were organized to carry out the color preference experiment, the visual data were accumulated to test the performances of the light sources and the results indicated that existing color rendering index have some deficiencies to assess the quality of the light source, which were needed to be modified for the theory of color science and industry application. The new CQS additional scales were calculated and the improvements were still insufficient for the LED light sources.

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