Product standard covering luminous signs with discharge lamps and/or LED (light emitting diodes) and/or EL (electroluminescent) lightsources with a nominal voltage not exceeding 1000 V, with the exclusion of general lighting, traffic- or emergency related purpose

2018 ◽  
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
Led Light ◽  
Nominal Voltage ◽  
Product Standard

scholarly journals Utjecaj različitog tipa umjetnog osvjetljenja na klijavost sjemena matovilca i kres salate

2017 ◽  
Vol 40 (6) ◽  
pp. 70-76
Author(s):  
Tomislav Vinković ◽  
Monika Tkalec ◽  
Nada Parađiković ◽  
MIro Stošić ◽  
Krunoslav Zmaić ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
Led Light

Cilj rada je bio utvrditi utjecaj LED (Light Emitting Diodes) i FLUO (fluorescentno svjetlo) osvjetljenja na klijavost i energiju klijanja sjemena te masu i visinu klijanaca matovilca i kres salate. Sjetva naturalnog sjemena provedena je u Petrijeve zdjelice u komori opremljenoj LED i FLUO lampama. LED lampe su bile opremljene crvenim (650-670 nm) i plavim (440-460 nm) LED diodama u omjeru 3:1. Istraživanje je provedeno u Laboratoriju za povrćarstvo, cvjećarstvo, ljekovito i začinsko bilje Poljoprivrednog fakulteta u Osijeku. Utvrđen je statistički opravdan utjecaj tipa osvjetljenja na energiju klijanja i klijavost sjemena matovilca, a veće vrijednosti utvrđene su uslijed primjene LED lampi. Suprotno, pod FLUO lampama je utvrđena značajno veća masa i visina klijanaca matovilca te visina klijanaca kres salate. Međutim, tip osvjetljenja nije značajno utjecao na klijavost i energiju klijanja te masu klijanaca kres salate. Prema tome, može se zaključiti da je odgovor na tip osvjetljenja uvjetovan biljnom vrstom već od samih početaka rasta i razvoja.

scholarly journals Compressive strength measurements of hybrid dental composites treated with dry heat and light emitting diodes (LED) post cure treatment

2014 ◽  
Vol 26 (3) ◽  
Author(s):  
Jenny Krisnawaty ◽  
Setiawan Natasasmita ◽  
Dudi Aripin
Keyword(s):  
Compressive Strength ◽  
Hybrid Composite ◽  
Light Emitting Diodes ◽  
Composite Resin ◽  
Hybrid Composites ◽  
Testing Machine ◽  
Dental Composite ◽  
Light Emitting ◽  
Led Light ◽  
Dry Heat

Hybrid composites are mostly used on large cavities as restorative dental materials, whether it is used directly or indirectly. The mechanical properties of composite resin shall increase if it is treated with post cure treatment. The aim of this study is to evaluate compressive strength differences between dry heat and Light Emitting Diodes (LED) treatment on the hybrid dental composite. A quasi-experimental was applied on this research with a total of 30 samples that were divided into two groups. Each sample was tested using LLOYD Universal Testing Machine with 1 mm/min speed to evaluate the compressive strength. The compressive strength results were marked when the sample was broken. The results of two groups were then analyzed using t-test statistical calculation. The results of this study show that post cure treatment on hybrid composite using LED light box (194.138 MPa) was lower than dry heat treatment (227.339 MPa), which was also significantly different from statistical analysis. It can be concluded that compressive strength of LED light box was lower than dry heat post-cure treatment on the hybrid composite resin.

scholarly journals Supplemental Lighting Orientation and Red-to-blue Ratio of Light-emitting Diodes for Greenhouse Tomato Production

HortScience ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 448-452 ◽  
Author(s):  
Paul Deram ◽  
Mark G. Lefsrud ◽  
Valérie Orsat
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Tomato Fruit ◽  
Fruit Production ◽  
Plant Production ◽  
Tomato Production ◽  
Light Emitting ◽  
Led Light ◽  
Red Led ◽  
Supplemental Lighting

Current greenhouse supplemental lighting technology uses broad-spectrum high-pressure sodium lamps (HPS) that, despite being an excellent luminous source, are not the most efficient light source for plant production. Specific light frequencies in the 400- to 700-nm range have been shown to affect photosynthesis more directly than other wavelengths (especially in the red and blue ranges). Light-emitting diodes (LEDs) could diminish lighting costs as a result of their high efficiency, lower operating temperatures, and wavelength specificity. LEDs can be selected to target the wavelengths used by plants, enabling growers to customize the light produced, to enable maximum plant production and limit wavelengths that do not significantly impact plant growth. In our experiment, hydroponically grown tomato plants (Solanum lycopersicum L.) were grown using a full factorial design with three light intensities (high: 135 μmol·m−2·s−1, medium: 115 μmol·m−2·s−1, and low: 100 μmol·m−2·s−1) at three red (661 nm) to blue (449 nm) ratio levels (5:1, 10:1, and 19:1). Secondary treatments for comparison were 100% HPS, 100% red LED light supplied from above the plant, 100% red LED light supplied below the plant, a 50%:50% LED:HPS mixture, and a control (no supplemental lighting). Both runs of the experiment lasted 120 days during the Summer–Fall 2011 and the Winter–Spring 2011–12. The highest biomass production (excluding fruit) occurred with the 19:1 ratio (red to blue) with increasing intensity resulting in more growth, whereas a higher fruit production was obtained using the 5:1 ratio. The highest marketable fruit production (fruit over 90 g) was obtained with the 50%:50% LED:HPS followed by 5:1 high and 19:1 high. Consistently the 5:1 high performed well in every category. LEDs have been shown to be superior in fruit production over HPS alone, and LEDs can improve tomato fruit production when mixed with HPS. LEDs provide a promising mechanism to enhance greenhouse artificial lighting systems.

scholarly journals Increases in Shoot Tissue Pigments, Glucosinolates, and Mineral Elements in Sprouting Broccoli after Exposure to Short-duration Blue Light from Light Emitting Diodes

2013 ◽  
Vol 138 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Dean A. Kopsell ◽  
Carl E. Sams
Keyword(s):  
Blue Light ◽  
Short Duration ◽  
Light Emitting Diodes ◽  
Mineral Elements ◽  
Light Emitting ◽  
Blue Led ◽  
Led Light ◽  
Shoot Tissue ◽  
Phytochemical Compounds ◽  
The Impact

Microgreens are specialty leafy crops harvested just above the roots after the first true leaves have emerged and are consumed fresh. Broccoli (Brassica oleacea var. italica) microgreens can accumulate significant concentrations of cancer-fighting glucosinolates as well as being a rich source of other antioxidant phytochemicals. Light-emitting diodes (LEDs) now provide the ability to measure impacts of narrow-band wavelengths of light on seedling physiology. The carotenoid zeaxanthin has been hypothesized to be a blue light receptor in plant physiology. The objective of this study was to measure the impact of short-duration blue light on phytochemical compounds, which impart the nutritional quality of sprouting broccoli microgreens. Broccoli microgreens were grown in a controlled environment under LEDs using growing pads. Seeds were cultured on the pads submerged in deionized water and grown under a 24-hour photoperiod using red (627 nm)/blue (470 nm) LEDs (350 μmol·m−2·s−1) at an air temperature of 23 °C. On emergence of the first true leaf, a complete nutrient solution with 42 mg·L−1 of nitrogen (N) was used to submerge the growing pads. At 13 days after sowing, broccoli plantlets were grown under either: 1) red and blue LED light (350 μmol·m−2·s−1); or 2) blue LED light (41 μmol·m−2·s−1) treatments for 5 days before harvest. The experiment was repeated three times. Frozen shoot tissues were freeze-dried and measured for carotenoids, chlorophylls, glucosinolates, and mineral elements. Comparing the two LED light treatments revealed the short-duration blue LED treatment before harvest significantly increased shoot tissue β-carotene (P ≤ 0.05), violaxanthin (P ≤ 0.01), total xanthophyll cycle pigments (P ≤ 0.05), glucoraphanin (P ≤ 0.05), epiprogoitrin (P ≤ 0.05), aliphatic glucosinolates (P ≤ 0.05), essential micronutrients of copper (Cu) (P = 0.02), iron (Fe) (P ≤ 0.01), boron (B), manganese (Mn), molybdenum (Mo), sodium (Na), zinc (Zn) (P ≤ 0.001), and the essential macronutrients of calcium (Ca), phosphorus (P), potassium (K), magnesium (Mg), and sulfur (S) (P ≤ 0.001). Results demonstrate management of LED lighting technology through preharvest, short-duration blue light acted to increase important phytochemical compounds influencing the nutritional value of broccoli microgreens.

Performance of Arabidopsis thaliana under different light qualities: comparison of light-emitting diodes to fluorescent lamp

2017 ◽  
Vol 44 (7) ◽  
pp. 727 ◽  
Author(s):  
Karin Köhl ◽  
Takayuki Tohge ◽  
Mark Aurel Schöttler
Keyword(s):  
Arabidopsis Thaliana ◽  
Light Source ◽  
Light Emitting Diodes ◽  
Seed Mass ◽  
Fluorescent Light ◽  
Chlorophyll Fluorescence Parameters ◽  
Light Emitting ◽  
Led Light ◽  
Improve Energy Efficiency ◽  
Fluorescent Lamps

For precise phenotyping, Arabidopsis thaliana (L.) Heynh. is grown under controlled conditions with fluorescent lamps as the predominant light source. Replacement by systems based on light emitting diodes (LED) could improve energy efficiency and stability of light quality and intensity. To determine whether this affects the reproducibility of results obtained under fluorescent lamps, four Arabidopsis accessions and a phytochrome mutant were grown and phenotyped under two different LED types or under fluorescent lamps. All genotypes had significantly higher rosette weight and seed mass and developed faster under LED light than under fluorescent lamps. However, differences between genotypes were reproducible independent of the light source. Chlorophyll content, photosynthetic complex accumulation and light response curves of chlorophyll fluorescence parameters were indistinguishable under LED and fluorescent light. Principal component analysis of leaf metabolite concentrations revealed that the effect of a change from fluorescent light to LED light was small compared with the diurnal effect, which explains 74% of the variance and the age effect during vegetative growth (12%). Altogether, the replacement of fluorescent lamps by LED allowed Arabidopsis cultivation and reproduction of results obtained under fluorescent light.

scholarly journals Comprehensive Study of Light-Emitting Diodes (LEDs) and Ultraviolet-LED Lights Application in Food Quality and Safety

2021 ◽  
Vol 15 (3) ◽  
pp. 1125-1135
Author(s):  
Sarah Finardi ◽  
Tuany Gabriela Hoffmann ◽  
Fernanda Raquel Wust Schmitz ◽  
Savio Leandro Bertoli ◽  
Mars Khayrullin ◽  
...  
Keyword(s):  
Fruits And Vegetables ◽  
Light Emitting Diodes ◽  
Food Preservation ◽  
Soluble Solids ◽  
Total Phenolic ◽  
Salmonella Spp ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Phenylalanine Ammonia Lyase Activity

Light-Emitting Diodes (LEDs) and Ultraviolet Light-Emitting Diodes (UV LEDs) consist in a semiconductor of light, that are emerging in the market, due to their singular characteristics, as being a solid-state cold source of light, which has potential application in food preservation. For this reason, this study lens to provide a review of the effects of LED and UV LED application in fresh fruits and vegetables, under refrigeration storage. Analyzing the LED role, in extending the shelf-life of postharvest food, these present the capability of improving the quality physicochemical and microbiological of fruits and vegetables, such as: color (chlorophyll), weight loss, total phenolic and flavonoid content, phenylalanine ammonia-lyase activity and total soluble solids. In addition, it’s able to stop chemical reactions and increasing the activity of fruits and vegetable defenses. UV LED light, on the other hand, operates in an effective and straightway in the inactivation the food pathogens, such as Escherichia coli, Pseudomonas fluorescens and Salmonella spp, for example. Therefore, UV LED light can be applied to delay the senescence of foods, however, the wavelength must match the target organism, depending on the food.

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.

Sign in / Sign up

Export Citation Format

Share Document