Traditionally, mercury lamps have supplied this UV light, however mercury release from power generation and lamp disposal have generated discussion of harmful environmental impact. A potentially energy efficient and non-toxic alternative is the light-emitting diode, or LED, which can be made to emit at almost any desired wavelength.
LEDs are also more rugged and operate at lower voltages than glass containing mercury bulbs. Thus, LEDs are more compatible with portable water disinfection units, which could also be solar-powered and used in situations where centralized facilities are not available, such as disaster relief. LEDs currently require a lot of electricity to produce UV light, but researchers from around the world are focused on improving this efficiency.
LEDs are semiconductor devices that operate in much the same way as the tiny elements on a computer chip. The difference is that some of the electrons flowing into an LED are captured and release their energy as light. Because these are solid materials rather than gas-filled bulbs, LEDs are more compact and durable than alternative light sources. The first commercial LEDs were small red indicator lights, but engineers have developed new materials that emit in a rainbow of colors. Nitride-based LEDs are the most promising for pushing beyond the visible into the ultraviolet. Some of these UV LEDs are already being used in the curing of ink and the testing for counterfeit money, but for sterilization, shorter wavelength light is required. These short wavelength, or “Deep UV” LEDs, present a number of technical challenges and are predominantly implemented in highly specialized disinfection systems in industrial and medical applications, as well as other non-disinfection markets.
The Joint Symposium on Semiconductor Ultraviolet LEDs and Lasers (CLEO: 2011, May 1-6 in Baltimore) will feature several talks addressing these challenges, while highlighting current efforts to improve the efficiency of nitride-based LEDs. Max Shatalov of Sensor Electronic Technology in Columbia, S.C., will report an improved design for making high-power UV LEDs that would be especially good for knocking out bacteria. From the birthplace of nitride (blue and white) LEDs, Motoaki Iwaya from Meijo University in Japan will describe a joint effort with Nagoya University to extend the range and improve the efficiency of UV LEDs.
The application of these UV LEDs is also being pursued in a related CLEO: 2011 session. Gordon Knight from Trojan Technologies in Canada will review advances in production of novel UV light sources, along with necessary validation procedures for verifying the operation of water disinfection systems in a one-hour tutorial.
Presentation JTuD1, “High Power III-Nitride UV Emitters,” by Max Shatalov et al. is at 11 a.m. Tuesday, May 3.
Presentation JTuD2, “IQE and EQE of the nitride-based UV/DUV LEDs,” by Motoaki Iwaya et al. is at 11:30 a.m. Tuesday, May 3.
Tutorial ATuD1, “Water and Air Treatment Using Ultraviolet Light Sources,” by Gordon Knight is at 1:45 p.m. Tuesday, May 3.CLEO: 2011 Program Information
Plenary Session keynote speakers include Donald Keck, retired vice president of Corning, talking about making the first low-loss optical fibers; James Fujimoto of MIT, talking about medical imaging using optical coherence tomography (OCT); Mordechai (Moti) Segev of the Technion-Israel Institute of Technology, speaking about the localization of light; and Susumu Noda of Kyoto University, talking about the control of photons in photonic crystals.
Online resources:• Conference program: http://www.cleoconference.org/Conference_Program
• Conference Registration: http://www.cleoconference.org/registrationPress Registration
Angela Stark | Newswise Science News
Illinois team finds Wigner crystal -- not Mott insulator -- in 'magic-angle' graphene
25.09.2018 | University of Illinois College of Engineering
Measuring Smallest Magnetic Fields in the Brain Using Diamond and Laser Technology
25.09.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF
Our brain is a complex network with innumerable connections between cells. Neuronal cells have long thin extensions, so-called axons, which are branched to increase the number of interactions. Researchers at the Max Planck Institute of Biochemistry (MPIB) have collaborated with researchers from Portugal and France to study cellular branching processes. They demonstrated a novel mechanism that induces branching of microtubules, an intracellular support system. The newly discovered dynamics of microtubules has a key role in neuronal development. The results were recently published in the journal Nature Cell Biology.
From the twigs of trees to railroad switches – our environment teems with rigid branched objects. These objects are so omnipresent in our lives, we barely...
The Fraunhofer FEP has been involved in developing processes and equipment for cleaning, sterilization, and surface modification for decades. The CleanHand Network for development of systems and technologies to clean surfaces, materials, and objects was established in May 2018 to bundle the expertise of many partnering organizations. As a partner in the CleanHand Network, Fraunhofer FEP will present the Network and current research topics of the Institute in the field of hygiene and cleaning at the parts2clean trade fair, October 23-25, 2018 in Stuttgart, at the booth of the Fraunhofer Cleaning Technology Alliance (Hall 5, Booth C31).
Test reports and studies on the cleanliness of European motorway rest areas, hotel beds, and outdoor pools increasingly appear in the press, especially during...
The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.
This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.
Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...
Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.
"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...
A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.
Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...
21.09.2018 | Event News
03.09.2018 | Event News
27.08.2018 | Event News
26.09.2018 | Trade Fair News
26.09.2018 | Life Sciences
25.09.2018 | Health and Medicine