scholarly journals Method to improve the survival of night-swarming mayflies near bridges in areas of distracting light pollution

2017 ◽  
Vol 4 (11) ◽  
pp. 171166 ◽  
Author(s):  
Ádám Egri ◽  
Dénes Száz ◽  
Alexandra Farkas ◽  
Ádám Pereszlényi ◽  
Gábor Horváth ◽  
...  
Keyword(s):  
Detrimental Effect ◽  
Light Emitting Diode ◽  
Egg Laying ◽  
Small Rivers ◽  
Light Pollution ◽  
Simple Method ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Quality Degradation ◽  
Oviposition Sites

Numerous negative ecological effects of urban lighting have been identified during the last decades. In spite of the development of lighting technologies, the detrimental effect of this form of light pollution has not declined. Several insect species are affected including the night-swarming mayfly Ephoron virgo : when encountering bridges during their mass swarming, these mayflies often fall victim to artificial lighting. We show a simple method for the conservation of these mayflies exploiting their positive phototaxis. With downstream-facing light-emitting diode beacon lights above two tributaries of the river Danube, we managed to guide egg-laying females to the water and prevent them from perishing outside the river near urban lights. By means of measuring the mayfly outflow from the river as a function of time and the on/off state of the beacons, we showed that the number of mayflies exiting the river's area was practically zero when our beacons were operating. Tributaries could be the sources of mayfly recolonization in case of water quality degradation of large rivers. The protection of mayfly populations in small rivers and safeguarding their aggregation and oviposition sites is therefore important.

scholarly journals A Supervisory Control Strategy for Improving Energy Efficiency of Artificial Lighting Systems in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 202
Author(s):  
Gianluca Serale ◽  
Luca Gnoli ◽  
Emanuele Giraudo ◽  
Enrico Fabrizio
Keyword(s):  
Control Strategy ◽  
Light Emitting Diode ◽  
Cost Savings ◽  
Energy Performance ◽  
Lighting System ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Lighting Control ◽  
Lighting Systems ◽  
Power Densities

Artificial lighting systems are used in commercial greenhouses to ensure year-round yields. Current Light Emitting Diode (LED) technologies improved the system efficiency. Nevertheless, having artificial lighting systems extended for hectares with power densities over 50W/m2 causes energy and power demand of greenhouses to be really significant. The present paper introduces an innovative supervisory and predictive control strategy to optimize the energy performance of the artificial lights of greenhouses. The controller has been implemented in a multi-span plastic greenhouse located in North Italy. The proposed control strategy has been tested on a greenhouse of 1 hectare with a lighting system with a nominal power density of 50 Wm−2 requiring an overall power supply of 1 MW for a period of 80 days. The results have been compared with the data coming from another greenhouse of 1 hectare in the same conditions implementing a state-of-the-art strategy for artificial lighting control. Results outlines that potential 19.4% cost savings are achievable. Moreover, the algorithm can be used to transform the greenhouse in a viable source of energy flexibility for grid reliability.

scholarly journals The Influence of Artificial Lighting Systems on the Cultivation of Algae: The Example of Chlorella vulgaris

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5994
Author(s):  
Beata Brzychczyk ◽  
Tomasz Hebda ◽  
Norbert Pedryc
Keyword(s):  
Chlorella Vulgaris ◽  
Light Emitting Diode ◽  
Radiant Energy ◽  
Biodiesel Production ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Single Side ◽  
Biological Compounds ◽  
Lower Light ◽  
Lighting Systems

Microalgae are a practical source of biological compounds for biodiesel production. This study examined the influence of three different light-emitting diode (LED) systems on the biomass production of green algae Chlorella vulgaris BA0002a. The cultivation was carried out in a photobioreactor illuminated from the bottom with a single side light jacket (PBR I), in a photobioreactor illuminated from the bottom with a double side light jacket (PBR II) and in a photobioreactor illuminated only from the top (PBR III). Research has shown that the intensification of algae cell production and growth depends on the light distribution and exposure time of a single cell to radiation. In the experiment, the highest growth of algae cells was obtained in the photobioreactor with double jacket and lower light panel. The lowest cell growth was observed in the photobioreactor illuminated only from above. For cultures raised in the PBR I and PBR II photobioreactors, increased oxygen production was observed, which was directly related to the increased production of biomass, which in turn was dependent on the increased amount of radiant energy.

scholarly journals Effect of the Spectral Quality and Intensity of Light-emitting Diodes on Several Horticultural Crops

HortScience ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 268-271 ◽  
Author(s):  
Miguel Urrestarazu ◽  
Cinthia Nájera ◽  
María del Mar Gea
Keyword(s):  
Plant Growth ◽  
Light Emitting Diode ◽  
Photon Flux ◽  
Photosynthetic Response ◽  
Light Spectrum ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Horticultural Crops ◽  
Distribution Study ◽  
Environment Chamber

Light-emitting diode (LED) lamps signify one of the most important advances in artificial lighting for horticulture over the last few decades. The objective of this study was to compare the cultivation of four horticultural plants using a conventional white LED tube (T0) light against one with a good spectral fit to the maximum photosynthetic response (T1) at two intensities. The experiment was carried out with two types of young lettuce, tomato, and bell pepper plants. In a controlled environment chamber, six and four lamps per square meter were used to achieve high (H) and low (L) intensity, respectively. We measured the lighting parameters illuminance (lux) and photosynthetic photon flux (PPF) intensity (µmol·m−2·s−1). The dry and fresh weight, leaf area (LA), and specific index were measured to gauge plant growth. The photosynthetic activity and energy efficiency (EE) were recorded for each species over 60 days of cultivation. The results clearly demonstrate that, compared with conventional LED lamps, the specific horticultural LED lamps with an improved light spectrum increased the EE of the evaluated vegetables by 26%. At both the studied light intensities, plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance (lux). We therefore suggest that a specific, detailed spectral distribution study be conducted to predict the effect of the specific quantity and quality of light used in this study on a single parameter of plant growth.

A Study on Energy Saving and Light Pollution of LED Advertising Signs

2011 ◽  
Vol 121-126 ◽  
pp. 2979-2984 ◽  
Author(s):  
Chen Ying Ho ◽  
Hsien Te Lin ◽  
Kuang Yu Huang
Keyword(s):  
Energy Consumption ◽  
Urban Areas ◽  
Light Emitting Diode ◽  
Outdoor Environment ◽  
Light Pollution ◽  
Light Emitting ◽  
Full Color ◽  
Average Luminance ◽  
Color Screens ◽  
Color Screen

Lighting advertising signs not only play an important role in outdoor lighting environment in Taiwan, but also become the main factor of energy consumption in urban areas at night. Light-emitting diode (LED) has been gradually used in advertising signs due to its advantages. However, in order to be conspicuous and legible in the daytime, signs that are excessively bright may result in considerable light pollution and energy waste at nighttime. Therefore, this research aims to measure the luminance of LED signs and traditional internally lighted signs, and analyze the light trespass from each signage. Based on the research results, the energy consumption from a LED full color screen is 12 times more than a traditional internally lighted sign per day. Statistically, all kinds of LED signs are much higher than traditional internally lighted signs in the percentage of excessive brightness and average luminance value. As for the light trespass, since the vertical illuminance on facade facing the signs increases with the increase of the sign area or the decrease of the distance between the sign and the facade, the vertical illuminance on facade facing the signs would exceed the limit of CIE even if the luminance of the signs achieves the standard of CIE in terms of the general conditions in Taiwan. This happens to LED full color screens in particular and thus results in considerable obtrusive light. To sum up, in order to reduce unnecessary energy consumption and improve the nighttime lighting quality for outdoor environment, this research recommends the luminance limitation for light dimming of LED advertising signs should refer to the zoning, time period, and sign area.

scholarly journals Encapsulation method developed for OLED devices mounted at laboratory

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Emerson Roberto Santos ◽  
Erik Yassuo Yuki ◽  
Wang Shu Hui
Keyword(s):  
Thin Film ◽  
Indium Tin Oxide ◽  
Electrical Resistance ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Simple Method ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Polymer Semiconductor ◽  
Encapsulation Process

A simple method with low cost of encapsulation for organic light emitting diode (OLED) devices mounted at laboratory was proposed to obtain considerable increase of the lifetime. In this study, it was used a capsule formed by: glass slide as substrate, a layer of polyvinyl acetate glue diluted in methyl alcohol, a layer of calcium oxide as secant and epoxy placed at the edges of capsule. The performance of this capsule was analyzed using a thin film of polymer semiconductor called as PEDOT:PSS, that is sensitive to moisture and oxygen from atmospheric air. The PEDOT:PSS thin layer was deposited between anode and cathode electrodes using commercial indium tin oxide (ITO) thin film deposited on glass substrate. The capsule was placed covering completely the PEDOT:PSS thin film, and the electrical resistance was measured by elapsed days. This result revealed lowest electrical resistance compared with other methods, showing also good performance as encapsulation process.

scholarly journals Growth and Flowering Responses of Seed-propagated Strawberry Seedlings to Different Photoperiods in Controlled Environment Chambers

2018 ◽  
Vol 28 (4) ◽  
pp. 453-458 ◽  
Author(s):  
Johshin Tsuruyama ◽  
Toshio Shibuya
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Photon Flux ◽  
Controlled Environment ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Daily Light Integral ◽  
Growth Properties ◽  
Performance System ◽  
Light Integral

The present study investigated growth properties and flowering response of seed-propagated strawberry (Fragaria ×ananassa) seedlings under artificial lighting with different photoperiods to support the development of a high-performance system for the indoor production of strawberry plug transplants. Seedlings of ‘Elan’ and ‘Yotsuboshi’ were grown for 38 days under sunlight in a greenhouse or under light-emitting diode (LED) illumination with photoperiods of 8/16, 12/12, 16/8, or 24/0 hours (light/dark) in growth chambers. The photosynthetic photon flux (PPF) in these photoperiods was maintained at 350, 230, 175, or 115 μmol·m−2·s−1, respectively, to provide the same daily light integral (DLI) of 10 mol·m−2·d−1. The average of DLI of sunlight was 9.9 mol·m−2·d−1. Seedling growth was greater with the 16- and 24-hour photoperiods than with sunlight even though all three treatments provided about the same DLI. Flower buds of the seedlings grown under longer photoperiods started significantly earlier after transplanting in ‘Elan’ but not in ‘Yotsuboshi’. Thus, strawberry transplant production under artificial lighting with an optimized photoperiod can provide high-quality transplants, although the effectiveness is cultivar-specific.

scholarly journals Light emitting diode (LED) use in artificial lighting for broiler chicken production

2014 ◽  
Vol 34 (3) ◽  
pp. 422-427 ◽  
Author(s):  
Mayara R. de Santana ◽  
Rodrigo G. Garcia ◽  
Irenilza de A. Naas ◽  
Ibiara C. de L. A. Paz ◽  
Fabiana R. Caldara ◽  
...  
Keyword(s):  
Weight Gain ◽  
Feed Intake ◽  
Broiler Chickens ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Carcass Weight ◽  
Feed Conversion ◽  
Carcass Yield ◽  
Light Emitting ◽  
Artificial Lighting

Light emitting diode (LED) has been used in commercial poultry industry by presenting superior energy savings and providing feasibility on production process. The objective of this research was to evaluate performance and carcass yield of broiler chickens exposed to different LED colors compared with fluorescent lamps. For that, two experiments (E1 and E2) were performed and 2,646 Cobb® chickens were used. In experiment E1, male birds were exposed to 20 lux artificial lighting with red, yellow, blue, and white LED bulbs; and fluorescent bulb. In experiment E2, male and female birds were exposed to 15 lux artificial lighting with red and blue LED bulbs; and fluorescent bulb. Cumulative weight gain (kg), feed intake (kg), feed conversion, hot carcass weight (kg), carcass yield (%), and breast and thigh + drumstick yield (%) were used as response variables. Results showed no difference (p > 0.05) among treatments for performance, carcass yield, and cut yield in experiment E1. In experiment E2 there was only difference between genders (p < 0.05) and males showed higher total weight gain, feed intake, hot carcass weight and thigh + drumstick yield. Different LED color use had same effect as fluorescent lights on broiler performance and carcass yield.

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