It emits a deep-red light at a wavelength of 660 nanometers, which is perfect for plant photosynthesis. With an efficiency of 37 percent — one of the highest for a light source of this color — it also yields considerable energy savings compared to conventional lamps. In a pilot project in Denmark, which used around 50,000 LEDs to illuminate a cultivation area of several thousand square meters, power consumption in the greenhouse fell by 40 percent.
Relatively little of the light used by plants for their growth is from the visible light spectrum. Chlorophyll molecules mostly absorb deep-red and blue light for the purposes of photosynthesis. Osram Opto Semiconductors has therefore developed an extremely efficient red LED with an emission curve that is very closely matched to the spectral sensitivity of chlorophyll. The new LED is based on the thin-film technology used for high power semiconductor chips.
In greenhouse cultivation, some plants are grown on several levels stacked on top of one another. For this reason, the new LED is available in two variants, each with a different beam angle. The Golden Dragon Plus has a beam angle of 170 degrees and is therefore well suited for use in reflector lamps for illuminating large areas under cultivation. By contrast, the Oslon SSL LED, with a beam angle of 80 degrees, is designed for use in multi-level applications, such as those for the cultivation of lettuce. Using LED light, it is also possible to promote different growth phases of the plant under cultivation. Red light, for example, encourages plants to grow in length, whereas blue light fosters bud formation, for example. Controlled variation of the proportion of blue light between ten and 30 percent reduces use of fertilizer and other chemicals.
Compared to conventional high-pressure sodium lamps, the luminous efficacy of the system as a whole is 60 percent higher with red and blue LEDs. And with a service life of 100,000 hours, the LEDs provide maintenance-free operation for many years. Also involved in the pilot project with Osram were Arrow Electronics and Fiona Lighting A/S, a Danish company specializing in LED lighting for commercial horticulture. Highly efficient LED lighting forms part of the Siemens environmental portfolio, which generated around €28 billion in sales for the company in fiscal year 2010.
Dr. Norbert Aschenbrenner | Siemens InnovationNews
Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH
Engineers find better way to detect nanoparticles
14.08.2017 | Washington University in St. Louis
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
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