More Quickly Predict Phosphor Materials for LEDs

Jakoah Brgoch, assistant professor of chemistry at the University of Houston, and members of his lab published a paper on Oct. 22 in Nature Communications describing how machine learning speeds discovery of new materials. By scanning a huge number of compounds for their key attributes they were looking for a new light conversion material that could be used in white LEDs.

The researchers have devised a new machine learning algorithm that is efficient enough to run on a personal computer and predict the properties of more than 100,000 compounds in search of those most likely to be efficient phosphors for LED lighting. They then synthesized and tested one of the compounds predicted computationally – sodium-barium-borate – and determined it offers 95 percent efficiency and outstanding thermal stability. 

Machine Learning

The researchers used machine learning to quickly scan huge numbers of compounds for key attributes, including Debye temperature and chemical compatibility. Brgoch previously demonstrated that Debye temperature is correlated with efficiency. 

LED, or light-emitting diode, based bulbs work by using small amounts of rare earth elements, usually europium or cerium, substituted within a ceramic or oxide host – the interaction between the two materials determines the performance. The paper focused on rapidly predicting the properties of the host materials. 

Brgoch said the project offers strong evidence of the value that machine learning can bring to developing high-performance materials, a field traditionally guided by trial-and-error and simple empirical rules. “It tells us where we should be looking and directs our synthetic efforts,” he said. 

Collaboration

Brgoch collaborates with the UH Data Science Institute and has used the computing resources at the UH Center for Advanced Computing and Data Science for previous work. The algorithm used for this work, however, was run on a personal computer. 

The project started with a list of 118,287 possible inorganic phosphor compounds from the Pearson’s Crystal Structure Database; the algorithm whittled that to just over 2,000. Another 30 seconds and it had produced a list of about two dozen promising materials. That process would have taken weeks without the benefit of machine learning, Brgoch said. 

His lab does machine learning and prediction, as well as synthesis, so after agreeing the algorithm-recommended sodium-barium-borate was a good candidate, researchers created the compound. It proved to be stable, with a quantum yield or efficiency of 95 percent, but Brgoch said the light produced was too blue to be commercially desirable. That wasn’t discouraging, he said. “Now we can to use the machine learning tools to find a luminescent material that emits in a wavelength that would be useful. 

“Our goal is to make LED light bulbs not only more efficient but also improve their color quality, while reducing the cost.” 

More to the point, the researchers said, they demonstrated that machine learning can dramatically speed the process of discovering new materials. This work is part of the Brgoch research group’s broader efforts to using machine learning and computation to guide their discovery of new materials with transformative potential.

Source: LED Professional

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Digital Lighting Innovation - LED Lighting in St. Peter’s Basilica

Initial lighting tests show that illumination of the domes is 10 times brighter than before.

Planning for the new LED lighting system for the world’s largest church has entered its final phase: The lighting calculations and simulations have been successfully completed. In the basilica, the LED lighting system has been tested in many areas, and everyone involved is really pleased with the results. Tests show that the illumination level of the domes is 10 times brighter than before. The new indirect lighting system also eliminates unsightly drop shadows on the circular inscription, which is carved into the wall below the cornices of the basilica.

“At St. Peter’s Basilica, we are able to demonstrate our lighting expertise once again,” says Olaf Berlien, CEO of OSRAM Licht AG. “A total of 700 custom-made luminaires with more than 100,000 powerful light-emitting diodes from Regensburg brilliantly illuminate this tremendous building in a way never seen before. And the technology of our Italian subsidiary Clay Paky bathes individual works of art and statues at the Basilica in dazzling light.” 

New Lighting System

“We are really pleased with the new lighting system for St. Peter's Basilica,” said Monsignore Rafael De La Serrana Villalobos, Director Department Technical Services of the Governorate of the Vatican State (Servizi Tecnici del Governatorato dello Stato della Città del Vaticano). “During the first tests, we could clearly see details of artwork in the domes that we could only guess at in the past.”

The innovative LED light sources will create an unforgettable visitor experience, much like the brilliant results achieved by Osram at the Sistine Chapel and the Raphael Rooms. The new lighting system also will lower energy usage by about 85 percent. 

St. Peter's Basilica, a church that can hold up to 20,000 people, is about 190 meters long. The three naves are each 58 meters wide. The maximum height of the vault in the nave is nearly 46 meters, and the dome rises approximately 136 meters to the top of the cross. The interior rooms decorated with large mosaics serve as valuable jewelry boxes for some of the world’s most famous artwork, including the Baldachin by Bernini and the Pietà statue by Michelangelo. 

The lighting can be altered to suit the needs of the particular occasion. For television broadcasts from St. Peter's Basilica, the altar area will be lighted very brightly. The new lighting system accentuates the features of the materials used in the building and the architecture itself. In the process, the plasticity of the sculptures and marble surfaces, as well as the architecture itself, are highlighted. All interiors decorated with mosaics – including the world's largest mosaic, which is approximately 10,000 square meters – will radiate beauty never seen before. The decisions made in this area were made jointly: The Department of Utilities at the Governorate of Vatican City and the Fabric of St. Peter’s made key contributions to this work, and the Vatican Museums provided their artistic expertise. The lighting project is scheduled to be completed by Christmas 2018.

Source: LEDinside

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Guide to Outdoor Lighting

Outdoor lighting tips from landscape designer – from types of outdoor lighting to illuminating trees and LED outdoor lighting.

Outdoor lighting design enhances and extends the usability of outdoor spaces and should be integral to all garden design.

Garden lights are needed for safety after dark as well as aesthetic reasons.

TYPES OF OUTDOOR LIGHTING

There are many types of outdoor lights: spike lights (spotlights on spikes that you push into the ground), hanging lights, in-ground lights (which give a clean and flush finish), wall lights, step lights, bollards, pedestals, poles, feature lights and submersible lights for pools.

Landscape lighting needs to be either in sympathy with the architecture of your home, or invisible. Subtle bronze or tarnished copper fittings blend well with most settings. If you have painted walls, consider colored fittings to match a wall or accent colors.

The home entrance looks great framed by light at night; you can’t go wrong lighting either side of a gate. For this purpose, we use everything from wall-mounted coach lights to downlights and in-ground fittings.

A spike light is best for illuminating trees or garden features, and I always use LED outdoor lighting. For small trees I recommend using five watts; for trees taller than 15m, use eight watts. A trick I like to use is to angle the light to reflect off the tree trunk into the foliage.

FAVORITE LED LIGHT FITTING

I love the Accento 5 in-ground bronze spike light by Gardens at Night. It’s well-made, LED, blends with the landscape and casts a warm light.

OUTDOOR DINING

I recommend outdoor wall lights for dining alfresco; overhead lighting directly above a dining table can be too harsh. A well-lit outdoor entertaining area will usually provide enough light for dining.

However, if you’re lucky enough to be seated under a large tree, think about tree-mounted fittings to create pools of light, which can look very cool and casual.

PATHWAY LIGHTS

To light up a pathway, I find bollards are usually best. I prefer small, machined fittings made from bronze to blend with the plant material. Lots of people use spike lights for this purpose, but I find they produce too much light for paths, and often the light source is too much on display.

Source: Guide to Outdoor Lighting

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LED Lighting Technology - Vertical Farming

LED Grow Lights technology has started to replace the traditional lighting lamps such as HID, HM, Fluorescent in the horticulture sector. The reason for this is the fact that we can get more light output per Watt and to control the different growth stages of the plants by controlling the spectrum combination. LED Grow Lights are used in some horticulture applications such as Vertical Farming, Greenhouse Lighting, Plant Speed Breeding, Microgreen Growing, Algae Research and Production, Tissue Culture, Plant Grafting, Seedling Production, Phytopathology, Arabidopsis Practices, and Other Scientific Studies.

Why LED Grow Lights?

LED Grow Lights provide 70% energy saving more than traditional tech. The most important reason for this is that the spectrum of the LED grow lights can be filtered to provide high-quality lighting to plants because plants do not absorb all spectrums of the light perceived by the human eye. Therefore, unnecessary spectrum ranges in HPS, MH or fluorescent lamps can be filtered by this tech. At the same time, the filtered special spectrum values can be given to the plant at different rates according to the development stages of the plants. This is another case that is ensured to be efficiency.

In addition, LED technology produces less heat than other traditional lamps. The majority of the energy used in traditional lamps is transformed into heat. This ratio is lower with LED technology. Since LED systems can adapt to dimming technology and have a long lifespan, it provides more advantage to the customer during the plant production process in vertical farming, greenhouse, and all other applications.

Vertical Farming Technology

Vertical Farming is one of the most popular methods to grow special plants in the small growing area without external effects. Artificial LED lighting is one of the most important factors for high crop yield in vertical farming technology. The indoor farming method provides more facility to grow different plants in a controlled environment such as lettuce, spinach, cress, parsley, arugula, herbs, microgreen species and more…

Vertical farming technology is a special plant production method that is becoming widespread. It is the name given to the cultivation of plants in stable environments away from external factors in special closed areas. In this type of farming, there are considerable savings in the needed space, because many more areas can be made available by using layered systems in the unit area. In this technique, temperature, humidity, solution, pH, EC, and light can be easily controlled, and high-yielding healthy plant production is possible. In addition, bacterial, fungal and viral diseases are generally not present in these sterile environments, so chemical disinfection is not needed which positively affects the health of people. Some other names of vertical farming techniques that are used include Plant Factory, Urban Farming, City Farming.

Better quality plant production with suitable methods in Vertical farming technology is a topic that needs further study by vertical farming companies to protect the future of people and the world.

Source: Horticulture LED Grow Light Technology: Vertical Farming

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