Harmonic emission of LED lighting

Networked light-emitting diode (LED) lighting systems form an important part of smart buildings and the Internet of Things. Plug-and-play extra-low-voltage LED lighting systems are attractive because they can be installed and reconfigured or expanded by the end user. Adding network/control/programming abilities to these LED lighting systems increases the appeal to the end user—to be in charge of electricity usage as well as the aesthetics involved. However, these LED lamps as well as billions of other proliferating dc-based electronic appliances all require some form of dc power supply which hampers power-line networking and is a threat to the future success of such systems in smart buildings. A novel power-line interfacing technique, coupling diversity, is tested and modeled to investigate its potential to mitigate this threat which is posed by the worldwide increasing number of dc power supplies. Simulations and live results have yielded gains of up to 2 dB for 12-V LED systems. However, the most important result is a more consistent performance displayed by the novel technique when parameters such as cable topology, cable length, voltage, and impedance levels are varied.

Libya is one of the countries blessed with high potential of renewable energy. Currently, the electricity in Libya is produced from fossil fuel to meet the demand on the local electricity market. In the near future, the demand on the energy will increase significantly. The growth in energy demand will lead to more oil and gas consumption in Libya. Additionally, the CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emissions will increase substantially. Therefore, Libya should make an urgent plan to use its alternative energy supplies to cover some of its load requirements. For example street lighting forms around 20% of the electricity consumption. The street lighting system in Libya is based on the high pressure sodium lamps which are powered from the electricity grid. The lamp rating ranges from 250 to 400 watts. As the country struggles to satisfy its electricity demands we propose replacing the conventional street lighting system with solar powered LED (Light emitting Diode) lighting system. The paper presents a case study for 4 km solar street lighting system in Almarj city. Two proposals are investigated, the conventional lighting system and the solar powered LED lighting system. A feasibility study of the street lighting system is carried out. The cost, energy savings and the CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emission of the two proposed systems are compared. The cost of the solar powered LED street lighting system is 1,250,200 LD, while the cost of the high pressure Sodium lamp street lighting system is 2,117,255 LD. Additionally, the solar powered LED street lighting system has no CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emissions.

Light-emitting diode (LED) airfield lighting is growing in use at airports in the United States and abroad. The objective of the present synthesis study is to provide documentation about the performance of LED airfield lighting systems, and it is primarily intended for airfield operations managers and airport electrical maintenance staff. Information about LED lighting systems in terms of performance, cost, and other operations issues is not readily found in a single location. This report is an effort to gather information about airport experiences and feedback with LED airfield lighting. A literature review and a survey of individuals representing airports having experience with LED airfield lighting were conducted. Individuals from 22 airports and aviation agencies agreed to participate in the survey and all 22 completed it (a 100% response rate).

We investigated the synergetic effect between light-emitting diode (LED) lighting efficiency and building energy savings in heating and cooling using an alternative thermal operating system (ATOS) of indoor LED lighting integrated with the ventilation system of a building as an active cooling device. The heat generated from LED lighting and the indoor lighting illuminance were experimentally determined. The indoor heat gains in cooling and heating periods were determined using measurement data; the annual energy savings of an office building in heating and cooling were calculated through simulation. The LED lighting illuminance increased by approximately 40% and the lighting contribution for indoor heat gain was 7.8% in summer, while 69.8% in winter with the ATOS. Consequently, the annual total energy use of the office building could be reduced by 5.9%; the energy use in cooling and heating was reduced by 18.4% and 3.3%, respectively.

Pinus pseudostrobus Lindl. is a species endemic to Mexico and is widely used in reforestation programmes, as it is highly adapted to poor, shallow, limestone soils and has high commercial importance. However, it is necessary to preserve this genetic material since it is in trouble due to high rates of deforestation, land use change, and forest fires, so it is necessary to have effective strategies to obtain good quality seedlings. Due to the properties of LED (light emitting diode) lamps used for illumination in the production of in vitro plants, the effects of two different lighting systems (LED and fluorescent) on an in vitro culture were analysed for the morphological characteristics of the growth and photosynthetic pigment content in P. pseudostrobus seedlings. The length and root size of the seedlings were affected by the type of illumination, where a red LED light was the most effective at 30 days of evaluation. However, a blue LED light was equally effective as a red LED light at 60 days of seedling development. On the other hand, the fluorescent light was better in terms of the number of needles in the first stage, but we found the blue LED light to be better in the second stage. For the photosynthetic pigment content, the highest values were found with the blue LED light. The results showed that the LED lighting system favours the growth, development, and photosynthetic pigment content of the species under study.

Effects of light-emitting diode light v. fluorescent light on growing performance, activity levels and well-being of non-beak-trimmed W-36 pullets

In recent years, the use of Light Emitting Diodes (LEDs) in the horticulture sector has gained popularity. LEDs can be utilized as supplemental illumination in greenhouse production systems or as the primary light source in indoor farming.In the current study, the impact of nighttime supplemental LED was compared with the use of natural light.The study revealed that the nighttime supplemental LED light for 8 hours increased the average daily light integral (DLI) by 10.72%.Hemp plants grow to a height of 70.8011.12cm when placed under natural light, compared to 83.6017.05cm under additional LED lighting at night.Hemp plants with LED light had an average of 16.201.79branches, whereas those with natural light had an average of 13.404.45.The average weight of dry inflorescences collected under LED light was 29.4011.84g, whereas those picked under natural light were 29.009.77g.The average cannabidiol (CBD) concentration was 10.310.33%when nighttime supplemental LED light was used, compared to 8.530.12%for natural light.The group that received nighttime supplemental LED light increased their CBD contents by 20.87%.This study has verified that nighttime supplemental LED lighting system can accelerate the secondary metabolism rate of C. sativa when compared with those plants cultivated under normal solar irradiance.

This study aims to analysis at the composition of fish catches and the fishing effectiveness of fixed lift nets fitted with LED lights of varying color combinations. This research was carried out from May to June 2019, located in the waters of Pangkajene Regency and the Islands. Two fixed lift nets units, 16 white light Emitting Diode (LED) lights and 16 pairs of white blue and yellow combination lights, Global Positioning System (GPS), Stop watch, Digital scale, Digital camera, Logbook, Meter, Current meter, Thermometer, Refractometer, and Lux meter. The research method used in this study is Experimental fishing in fixed lift nets fishing operations using LED lights. Experimental research of white and white combination LED light color (control), and blue, white and yellow LED light color (Treatment) used in 2 fixed lift nets. The fixed lift nets used is 15 meters long and 15 meters wide with a height of 25 meters from the seabed to the top pole with a building height of 10 meters above sea level. The data collection technique was carried out by following directly the catching operation of two fixed lift nets with different color combinations of lights. The data collected is the position of the fishing ground and catch data. Data analysis was carried out qualitatively and quantitatively. Qualitative analysis by looking at the technical aspects of operations on the fixed lift nets and data tabulation. Quantitative analysis was carried out using statistical methods and comparison of fish catches using two treatments using LED light colors. The results show that the composition of fish catches using color combinations (white, blue and yellow) shows higher yields when compared to white. The composition of the catch in the fixed lift nets is divided into three groups, namely the main catch (main catch), bycatch (bycatch) and discarded catch (discard). The use of a combination of LED lights on the fixed lift nets got a catch of 1,347.21 Kg, while the use of white LED lights got a catch of 906.21 Kg. The difference between the catches of the two treatments was 441 kg or 49% of the fish caught using white LEDs. From these results it can be concluded that the use of color combinations of LED lights is more effective than the use of white LED lights.

Lighting systems with a big number of luminaires in large halls are a case of distributed loads that need topologies with modularity, whenever possible to ensure a uniform distribution of the supplying circuits, an easier installation, management, and maintenance. The light emitting diode (LED) luminaires give a great impact on the system operation due to their auxiliary series devices and to the high inrush currents of the ac–dc switching power supplies. This article proposes a topology to design LED lighting systems, configured in a modular scheme of a main ac distribution and a branch dc distribution supplying luminaires clusters. Each cluster is provided as a “double-dual corded” equipment with double power supply and double control type, digital, and analogic. The suggested topology aims to make available a system that allows overcoming fault situations by design and permits maintenance activities limiting and recovering degradation conditions. In this way, the lighting system of special locations, for which there is the willingness-to-accept greater financial costs against loss service risks, can satisfy the requirement of continuous availability system. To provide more details on the proposed design criteria this article describes, as case study, the lighting system of a parliamentary hall with one thousands of luminaires.

To effectively introduce light-emitting diode (LED) lights into Japanese flying squid Todarodes pacificus fisheries, information is required regarding how LED lights affect physiological responses of the squid eye. In order to examine the effects of LED emission-color on squid eyes, we observed the pupillary constriction and migration of black-screening pigment in the retina. The pupils constricted in all squid after exposure to LED lights; the pupils gradually opened and pigment migration occurred. Both of the physiological responses to LED light were affected by blue, green, and white lights, which have wavelengths close to the visual pigment sensitivity peak in T. pacificus (482 nm). However, response rates were much lower under red colored LED, which comprises wavelengths that are far from the visual pigment sensitivity peak. Thus, the eyes of squid responded sensitively to light which included the wavelengths close to the visual pigment sensitivity peak of T. pacificus and responded little to the light which did not include these wavelengths. These results suggest that the eyes of T. pacificus react in different ways to various LED light colors, where the first reaction to a lighting change is the pupillary response, and pigment migration occurs only if the illumination continues.

Lumen depreciation, the condition that the light output falls below a fraction of its peak output, is known to be the main failure mode in light emitting diodes (LEDs). In lighting systems comprising multiple LEDs, lumen depreciation leads to reduced average illuminance and a distorted illumination rendering. Diagnosing lumen depreciation in LED lighting systems is thus an important problem. We propose an estimation approach to diagnosing individual LED failures using a photosensor system. We specifically study the impact of perturbations in the photosensor positions on diagnosability by analyzing the sensor output matrix-the matrix relating the luminous flux values of the multiple LEDs to the measurements at the photosensor system. The conditions on diagnosability are first derived in terms of bounds on the smallest singular value of the sensor output matrix. Subsequently, sufficient conditions are derived on the photosensor positions to ensure that individual LED lumen depreciations are diagnosable. Numerical results are provided to validate our analytical results.

The rapid development of Virtual Reality (VR) technology and the Internet of Things (IoT) is enabling innovative user experiences across various fields.In particular, the integration of Head-Mounted Display (HMD) based controllers with LED (Light Emitting Diode) lighting systems serves as a prime example of such technological innovation, elevating the interaction between virtual spaces and the real environment to a new dimension.Based on this technological backdrop, this study develops a system that allows multiple users to control LED lighting within a virtual reality environment simultaneously, thereby proposing a new

The objectives of the study were to analyse the response of dominant fish to different light colours that reflect the wavelength of light and to analyse the species composition of the gillnet catch to determine the fish that are positively phototaxis to LED light. Data collection was conducted using the experimental method. The experimental design used 1 unit of bottom gillnet gear with a mesh size of 4 inches, and used LED (Light Emitting Diode) lights. Trials using green LED lights and white LED lights were operated simultaneously between the control gillnet (without LED lights) and the experimental gillnet (with LED lights). The results of statistical analysis of gillnet catches with green LED light aids with white LED light aids and control nets have a significant effect on the number of gillnet catches. The results were: (1) The number of fish caught at a distance of &lt; 1 m and at a distance of 1-2 m, this proves that many fish are attracted to light (positive phototaxis); (2) Proven by gill net fishing gear using green LED light aids obtained fish weighing up to 77.7 kg. (3) It is proven that the distance of the lamp with the position of the fish caught on the net sheet can produce the highest weight of fish caught, on green LED lights at a distance of &lt;1 m the weight of the fish reached 30.89 kg.

Objective:To evaluate the microhardness of resin-modified glass-ionomer cements (RMGICs) photoactivated with a blue light-emitting diode (LED) curing light.Material and Methods:Thirty specimens were distributed in 3 groups: Fuji II LC Improved/GC (RM1), Vitremer/3M ESPE (RM2) and Filtek Z250/ 3M ESPE (RM3). Two commercial light-curing units were used to polymerize the materials: LED/Ultrablue IS and a halogen light/XL3000 (QTH). After 24 h, Knoop microhardness test was performed. Data were submitted to three-way ANOVA and Tukey's test at a pre-set alpha of 0.05.Results:At the top surface, no statistically significant difference (p>0.05) in the microhardness was seen when the LED and QTH lights were used for all materials. At the bottom surface, microhardness mean value of RM2 was significantly higher when the QTH light was used (p<0.05). For RM1, statistically significant higher values (p<0.05) were seen when the LED light was used. No statistically significant difference (p>0.05) was seen at the bottom surface for RM3, irrespective of the light used. Top-to-bottom surface comparison showed no statistically significant difference (p>0.05) for both RMGICs, regardless of the light used. For RM3, microhardness mean value at the top was significantly higher (p<0.05) than bottom microhardness when both curing units were used.Conclusion:The microhardness values seen when a LED light was used varied depending on the restorative material tested.

This study examined the interactive effects of supplemental LED (Light-emitting diode) lighting and foliar silicon application on the growth, physiology, and nutrient status of Physalis angulata under different levels of salinity-alkalinity stress in a hydroponic system. Plants were exposed to three stress levels (control, moderate, severe), two silicon concentrations, and four light regimes (natural, blue: red, red, blue). Salinity-alkalinity stress significantly reduced plant height, stem diameter, leaf area, shoot and root biomass, and physiological characteristics, but these negative effects were alleviated by silicon and LED treatments. Both red and blue LED lights benefited plant growth and physiology, with red light being generally more effective than blue for increasing vegetative growth and nutrient uptake, especially under stress. Blue light alone had a moderate effect, enhancing certain growth aspects. The combination of blue and red light (blue:red) consistently outperformed either color alone across most traits. The combined use of blue: red light and silicon further increased plant height, stem diameter, leaf area, and shoot biomass compared to the control. Overall, integrating silicon nutrition with targeted LED lighting improved plant growth and nutrient acquisition, enhancing the tolerance of Physalis angulata to salinity-alkalinity stress and offering a promising strategy for crop resilience in challenging environments.