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Material gain

first_imgScientists from Harvard University and the Massachusetts Institute of Technology have developed a theoretical model of a material that one day could anchor the development of highly efficient solar panels.Traditional organic solar panels work by combining photons with light-sensitive materials, creating particles called excitons. Those particles are then channeled through the material to an interface, where they dump energy into electrons that flow along wires, producing electricity. The problem is that excitons aren’t easy to control. The particles are often trapped by defects in the material, and release their energy as light, reducing the efficiency of the panels.Inspired by cutting-edge theories in condensed matter physics and the development of quantum computers, the Harvard-MIT group used magnetic fields to force excitons to move in a specific direction, avoiding the traps that plague traditional materials. The system is described in a paper in Nature Materials.The research team was led by Professor of Chemistry and Chemical Biology Alan Aspuru-Guzik and included Joel Yuen-Zhou, a former Ph.D. student in Aspuru-Guzik’s lab who is now a postdoctoral fellow at MIT, and research associate Semion Saikin.“This effect has been identified in physics, in what’s called the quantum Hall effect, and in topological insulators, but we believe this is the first time this has been proposed in a practical way for excitons in molecular layers,” Aspuru-Guzik said. “What we wanted to ask was, can this be done in organic materials? Can you custom-tailor an organic material in such a way that, for certain excitation energies, excitons move in one direction, and when they confront obstacles, they can move around them?”Yuen-Zhou and Saikin began searching for molecules that fit a tightly defined set of criteria, and eventually settled on porphyrins, in part because they have been extensively studied.“These are just one example of a molecule that could work in this system,” said Saikin. “We don’t want to say that, experimentally, one has to do it with these molecules, but conceptually, we’ve shown that the electronic structure of these molecules is convenient for this system.”The system described in the paper, however, is about more than simply creating a film of porphyrin molecules.For the design to work, the team outlined how magnets could be used to prepare the molecules in specific quantum states to ensure they don’t interfere with one another.“In the absence of a magnetic field, it’s equally likely the excitons would go in one direction or another,” Aspuru-Guzik said. “We use some very clever quantum tricks, to ensure that, when we apply the field, one direction becomes more preferential.”Just as cars sitting in traffic on the highway are unable to turn around and drive in the opposite direction, Aspuru-Guzik said, excitons in this system are able to flow in only one direction, around the edges of the film.What’s more, Yuen-Zhou said, the quantum mechanics of the system permit a good deal of flexibility, allowing excitons to flow around defects in the material, just as a stream flows around obstructions.While it may be years before the material finds its way into commercial solar panels, Aspuru-Guzik believes it has the potential to increase their efficiency by creating a flow of excitons that moves along the panel’s interface, more efficiently transferring energy into electricity.“What we’ve done with this paper is a proof of concept, and we hope it’s the opening to a new era of excitonics.”last_img read more

Thursday Order of Events

first_imgTRACK PREP 5 – STOCK CAR HEATS (8 laps) MODIFIED “A2” (25 laps) TRACK PREP 2 – MODIFIED B’s (8 laps) 10 – MODIFIED HEATS (8 laps) 4 – MODIFIED B’s (8 laps) LATE MODEL DASH FOR CASH (10 laps) TRACK PREP LATE MODEL DASH FOR CASH (10 laps) LATE MODEL HOT LAPS 2 – MODIFIED B’s (8 laps) STOCK CAR “A1” (25 laps) 10 – MODIFIED HEATS (8 laps) TRACK PREP(Wednesday Modified Top 8 Qualifiers to Fan Zone) TRACK PREP (Wednesday Stock Car Top 8 Qualifiers in Fan Zone) 2 – STOCK CAR B’s (8 laps) TRACK PREP 2 – STOCK CAR B’s (8 laps) MODIFIED “A1” (25 laps) 10 – MODIFIED HEATS (8 laps) TRACK PREP (Wednesday Stock Car Top 8 Qualifiers in Fan Zone) TRACK PREP (Casey’s Late Model redraw in Fan Zone) STOCK CAR “A2” (25 laps) TRACK PREP 5 – STOCK CAR HEATS (8 laps) 4 – MODIFIED B’s (8 laps),LATE MODEL HOT LAPS LATE MODEL “A” (50 laps) TRACK PREP 4 – LATE MODEL HEATS (10 laps) 2 – LATE MODEL B’s (12 laps) 5 – STOCK CAR HEATS (8 laps) TRACK PREP(Wednesday Modified Top 8 Qualifiers to Fan Zone) TRACK PREP 2 – LATE MODEL B’s (12 laps) 2 – STOCK CAR B’s (8 laps) 2 – STOCK CAR B’s (8 laps) 10 – MODIFIED HEATS (8 laps) STOCK CAR “A2” (25 laps) 10 – STOCK CAR HEATS (8 laps) STOCK CAR “A1” (25 laps) TRACK PREP MODIFIED “A1” (25 laps) TRACK PREP TRACK PREP 10 – STOCK CAR HEATS (8 laps) 4 – LATE MODEL HEATS (10 laps) 10 – MODIFIED HEATS (8 laps) TRACK PREP (Casey’s Late Model redraw in Fan Zone) 5 – STOCK CAR HEATS (8 laps) LATE MODEL “A” (50 laps) MODIFIED “A2” (25 laps) 10 – MODIFIED HEATS (8 laps)last_img read more

FIFA says GFF has the authority to decide Elite League competition

first_imgWORLD governing body of football, FIFA, has confirmed that the Guyana Football Federation Inc. (GFF) has the right and authority to decide the composition of its competitions, including the Elite League.Four clubs have breached their obligations under the 2015 GFF Constitution by boycotting the 2016-2017 Elite League, after the GFF Executive Committee decided to include a further two teams in the league.In a letter to the GFF dated 1st February, 2017, FIFA’s General Secretary Fatma Samoura said: “It is within the power of the GFF Executive Committee to change the regulations of the Elite League, including determining the number of participating Clubs, unless there is a binding written agreement between the GFF and the Elite League which would state otherwise – to the best of our knowledge, however, such an agreement does not exist.”FIFA’s confirmation follows a similar move by the regional body CONCACAF.The GFF Executive Committee, elected with a mandate to reform football in Guyana, took the decision to expand the Elite League in order to broaden the geographical reach, commercial potential and competitiveness of the league, and to accelerate the development of football across the country.In her letter, Samoura referred to Article 36.2.i. of the GFF Constitution, which states that it is within the powers of the GFF Executive Committee to “draw up regulations governing the conditions of participation in and the staging of competitions organised by the Federation, including the playing schedule.”last_img read more