Effects Of LED Light Research Articles

LED照明的非视觉生物效应随色温变化研究

LED照明的非视觉生物效应随色温变化研究

The Effect of Light-Emitting Diode Light on the Physical Traits of Chicks

Environmental conditions including light are considered a critical element of chicks well-being. The aim of the present study was to investigate the effect of LED light on the physical traits of chicks. We took forty-one-day-old chicks and randomly separated it into two groups. The chicks in the first group were reared under the effect of incandescent lamp light and in the second one were under the effect of white LED lighting. Chicks were daily monitored for individual chick body, weight gain, feed intake, feather color and fear responses. The distance between chicks and source of light was 50 cm. Student’s t-test test was used for statistical evaluation at p < 0.05 level. The results of the current study showed that chicks reared under incandescent light bulb had significantly higher body weight compared with chicks reared under LED light. The magnitude of body weight in LED group was lower (1192.75 ± 149.9 g) compared to incandescent light group (1307.75 ± 110.5 g). The obtained results revealed that LED light reared chicks were more active; it showed long mobility duration and high levels of exploration in the farm as compared to those in incandescent light group. The results also indicated that incandescent light chicks were less fearful than LED chicks. Furthermore, the study showed that LED light reared chicks have pale pink combs and white feathers that cover all over the body. On the other hand, incandescent light reared chicks have dark red combs and whitish-yellow feathers that cover certain areas of the body especially chick wings, tail and head.

Sustainable crop production in greenhouses based on understanding crop physiology

More precise control of growth conditions has led to a strong increase in crop yield in greenhouses. To further improve crop production, product quality and sustainability, we need profound knowledge of the responses of plants to environmental conditions as well as crop management by growers (e.g., pruning and plant density). In young plants, rapid leaf formation initially boosts production through its role in intercepting light. However, we propose that many full-grown crops invest too much assimilate in new leaves. Responses of plants to the environment are seldom linear, and show many interactions. Furthermore, short- and long-term responses can be very different because of acclimation and feedback mechanisms. Therefore, research should not only study plant responses under constant conditions, but also analyse multiple interacting factors under fluctuating conditions. Controlling the climate should focus more on the microclimate near plant organs than on the average greenhouse climate. For instance, the temperature of the apical meristem may deviate by 4°C from that of the air. Leaf initiation rate depends on the temperature of the apical meristem, independent of the temperature of the other plant organs, and this has a significant impact on the plant phenotype. LED lamps open opportunities for energy saving while improving growth, yield and product quality, as they allow the instantaneous control of spectrum, intensity and direction of light, and the decoupling of lighting from heating. Effects of LED light on yield can be attributed to effects on leaf photosynthesis, plant morphology, which affects the absorption of light, and dry-matter partitioning. LED light can also trigger secondary metabolite production, resulting in increased disease resistance, or increased antioxidants such as vitamin C or anthocyanins. A next step in the control of the production process is indoor production without solar light in vertical farms. This step is boosted by developments in LED technology.

Effect of led light on in vitro growth and developmentof Anoectochilus roxburghii

Recently, LED lighting technology has been developed fast and strongly. It has been widely used in many new fields. LEDs have been tested as an artificial light source during micropagation and tissue culture of various plants species as an alternative to traditional light sources to save energy and improve the efficiency of the culture process. In this study, effects of LED light at different wavelengths and luminous intensities on growth of Anoectochilus roxburghii's buds in vitro were investigated. Anoectochilus's buds were cultured under the different light conditions, such as LED in monochromatic red (R), LED in monochromatic green (B) , LED in the green and red light combining with warm white light (W) in different ratios (BRW 1, BRW2, BRW3 and BR). After 3 months of culture, the results showed LED B at strong luminous intensity (79 ± 3 μmol.m-2.s-1) inhibited the growth and development of Anoectochilus roxburghii. In contrast, BR LED with low luminous intensity (30 ± 1μmol.m-2.s-1) had made a positive effect on growth and development of Anoectochilus roxburghii. The plant height (5,88 cm), root length (1,33 cm), fresh plant weight (0,169 g/plant), leaf area (0,82 cm2), fresh leaf weight (18,33 mg/leaves) of plants in vitro were found higher than those of plants grown under T5 fluorescent lighting conditions (as control). Besides, chlorophyll a, chlorophyll b and total chlorophyll content of leaves (285,40 µg/g, 196,40 µg/g, 481,80 µg/g respectively) were higher than in the control and other versions of LED combine. The results also showed that the LED light with combined ratio of BR = 1: 4 at luminous intensity of 30 μmol.m-2.s-1 were suitable for the growth of Anoectochilus roxburghii. Therefore, BR LED (1:4) light condition should be replaced fluorescent light sources in vitro culture of Anoectochilus roxburghii in future.

Effect of LED Lighting on Hatchability and Chick Performance of Chicken Eggs

Effect of LED Lighting on Hatchability and Chick Performance of Chicken Eggs

Effects of LED Lighting on Visual Comfort with Respect to the Reading Task

Effects of LED Lighting on Visual Comfort with Respect to the Reading Task

Effect of LED Lighting during Incubation of Fayoumi Eggs on Hatchability and Chick Performance

Effect of LED Lighting during Incubation of Fayoumi Eggs on Hatchability and Chick Performance

Effects of LED lighting on in vitro growth and long term survival of shoot cultures of potato and Brazilian ginseng

Effects of LED lighting on in vitro growth and long term survival of shoot cultures of potato and Brazilian ginseng

低照度LED光下人眼瞳孔的非视觉生物效应

低照度LED光下人眼瞳孔的非视觉生物效应

LED照明节律效应随年龄的变化

LED照明节律效应随年龄的变化

低照度LED光下人眼瞳孔的非视觉生物效应

低照度LED光下人眼瞳孔的非视觉生物效应

Effects of LED light on the production of strawberry during cultivation in a plastic greenhouse and in a growth chamber

This study was aimed at investigating the production of phytochemicals that determine fruit quality, and evaluating growth characteristics of mature strawberry plants during cultivation under three different wavelengths (blue, red and blue plus red) of LED light. Cultivation was conducted in two separate locations, namely, a growth chamber (GC) illuminated with LED lights as the sole light source and a plastic greenhouse (PG) which was given supplemental LED light in addition to ambient light. It was noted that leaves of plants cultivated in the GC under LED lights displayed elevated levels of chlorophyll compared with those cultivated in the PG. In contrast, plants cultivated in the PG with supplementary LED lights yielded much higher production of fruits than those cultivated in the GC. Moreover, fruits harvested in the PG were demonstrated to contain higher levels of organic acids than those harvested in the GC. When the effects of different LED lights were examined, a remarkably higher production of fruits was achieved in the PG when ambient light was supplemented with either blue LED light or combined blue and red LED light. Furthermore, it was also noted that greater accumulation of organic acids and phytochemicals such as phenolic compounds were observed in the fruits that had been cultivated in the PG when ambient light was supplemented with either red LED light or combined blue and red LED lights.

Effect of LED lighting on the cooling and heating loads in office buildings

LED lighting has the potential to provide energy savings, and in many countries, there are policies to encourage its use owing to its higher efficiency and longer life in comparison to other lighting fixtures. However, since 75–85% of the light electric power in LED lights is still generated as heat, the sole use of LED lighting in a building could have a negative effect on the cooling load. In this paper, we study the heating properties of LED lighting and establish a management strategy to exploit these properties to reduce the energy used for heating and cooling of buildings. Using a simulation program, the energy consumption of the Green Building in Daejeon, Korea, and the virtual building provided by the U.S. Department of Energy (DOE) was computed according for different light fixtures. A control strategy is more applicable to LED lighting than to general fluorescent lighting, especially for the cooling of a building, because the use of a return-air duct and the heat sinks on the LED fixtures allow the heat to be better directed. Deployment of LED lights in combination with such a control strategy can help to increase the energy efficiency of a building.

The Influence of LED Light on Basil Seeds Before Sowing and its Effects on Growing and Germination

The effects of LED light on plants after sowing are presented. In this research, we expose basil seeds with LED light before sowing them and we investigate influences on plant germination after sowing. Basil seeds were divided into four groups. First group was the control group and received no radiation. Second, third and fourth group were irradiated 6, 12, 24 hours ,respectively by the LED lamp with wavelength of 620-625 nm and 500-600 mcd from a distance of 1 cm. Exposure time was adjusted so that the end of exposure time was Simultaneity for all samples. Samples were implanted immediately after exposure. Control on samples showed that LED irradiate light on seeds before implantation increases the growth rate of this plant. Seeds that had been irradiated before implantation demonstrated more fertilization, better growth, average height and more uniformity.

48 Anti-inflammatory and bactericidal action of LED medolight device at treatment of dental diseases

48 Anti-inflammatory and bactericidal action of LED medolight device at treatment of dental diseases

GROWTH OF TOMATOES UNDER HYBRID LED AND HPS LIGHTING

The use of LEDs can be promising for greenhouse horticulture, but before it can be put into practice on a large scale more knowledge must be acquired on effects of LED lighting on crops. Furthermore, the growers will have to learn to grow their crops under LEDs and the efficiency of LEDs must increase even more. In order to gain more insight into the influence of LEDs on crop growth and production, an experiment was performed in the Wageningen UR greenhouses with a small Santa type tomato (‘Sunstream’) from October 2009 to June 2010. Four lighting treatments were applied, with each treatment in a separate greenhouse compartment: top lighting with HPS (1) or LED (2), and hybrid lighting with HPS above the crop in combination with LED lighting above the crop (3) or in between the canopy (interlighting) (4). The light intensity from the lamps in all treatments was maintained at 170 µmol m-2 s-1. The light was 50/50 divided between HPS and LED in the hybrid treatments. The climate in each treatment was adapted to the needs of the crop in each lighting system. The various lighting systems resulted in different greenhouse climates, in which more heating was required in the LED treatment and the least heating in the hybrid with interlighting. A strong crop developed under LED alone, and to maintain a proper crop balance the fruit load was altered by maintaining an extra tomato fruit per truss and increasing the stem density relative to that under HPS. The leaves of tomato grown under HPS were thinner and aged more rapidly in the winter than in the other treatments. Leaves lower in the canopy under LED alone or hybrid treatments had a higher photosynthesis capacity in the winter than leaves developed under HPS lighting. Differences in production were small, although the production under all LEDs was lower. There were only small differences in fruit quality. The amount of energy required per kilogram tomato was highest in the LED treatment and hybrid with top LED lighting. This was primarily due to the fact that a higher air temperature was necessary and these LEDs were cooled and the cost of cooling added to the use of energy. The consequences and future perspectives of the different types of supplementary lighting for crop growth and production as well as for crop management practices will be discussed.

Retraction of “The effect of LED lighting on color discrimination and preference of the elderly”

The following article from Human Factors and Ergonomics in Manufacturing & Service Industries, “The Effect of LED Lighting on Color Discrimination and Preference of the Elderly,” by Wenting Cheng, Jiaqi Ju, Yaojie Sun and Yandan Lin, published online on December 12, 2011 in Wiley Online Library (www.onlinelibrary.wiley.com), has been retracted by agreement between the authors, the journal Editors-in-Chief, Waldemar Karwowski and Gavriel Salvendy, and Publisher Wiley Periodicals, Inc. The retraction has been agreed as these articles were mistakenly published after being rejected.

Raman Study of the Effect of LED light on Grafted Bone Defects

Raman Study of the Effect of LED light on Grafted Bone Defects

ＬＥＤ照明が視認性・作業性に及ぼす影響に関する研究-高齢者を対象として-

ＬＥＤ照明が視認性・作業性に及ぼす影響に関する研究-高齢者を対象として-

Effects of LED Light on Synnema Formation in Isaria japonica

Effects of LED Light on Synnema Formation in Isaria japonica