CURRENT AFFAIRS GIST in S&T

CURRENT AFFAIRS GIST in S&T

1. IN what could be a significant development for both Russia and India, two VVER-1200 reactors of Russian design will be built near Rooppur in Bangladesh. The first pour of concrete for the foundation of the first unit took place on November 30, 2017, at Ishwardi village, near Rooppur, about 160 km from Dhaka.

2. Researchers at the Indian Institute of Science (IISc) in Bengaluru have created a novel hybrid of two remarkable materials called graphene and quantum dots in a breakthrough that may inspire highly efficient and controllable next-generation displays and LEDs.

Quantum dots are semiconductor nanocrystals with the potential to revolutionise diverse technologies, from photovoltaics and medical imaging to quantum computing. They can absorb ultraviolet (UV) light and produce sharp, bright colours, making them especially attractive for TVs, smartphones and LEDs. They are extremely tiny particles with properties vastly superior to conventional semiconductors. When activated by UV light, they can produce visible light in different colours depending on their size. Small dots produce blue light, for example, while large ones radiate red.

Quantum dots absorb light very well, but they are poor electrical conductors; quantum dot-based devices that convert light to electricity are, therefore, not very efficient.

Graphene, on the other hand, is almost transparent to light, but it is an excellent electrical conductor. When the two are combined, graphene could, in principle, quickly pull the absorbed energy away from quantum dots—cutting down energy loss—and convert it to an electrical signal, for example. This makes it possible to create devices such as photodetectors with extremely high efficiency. Adding graphene would also confer the ability to tinker with the output even after fabrication, or turn the device on and off at will.

Although the combination works well for photodetectors and sensors, it is practically useless for displays and LEDs because quantum dots lose their ability to emit light when fused with graphene. By modifying some experimental conditions, the IISc scientists have found a way to eliminate this effect and create a highly efficient and tunable hybrid material. The results of the study were published in ACS Photonics.

3. IceCube had detected a neutrino—the highly elusive, very weakly interacting and nearly massless elementary particle—with the highest energy ever. Its energy was above a whopping two million billion electronvolts (2 × 1015 eV), or 2 peta eV (PeV). This’ is about 1,000 times the energy to which protons are accelerated at the Large Hadron Collider (LHC), the highest-energy man-made particle accelerator, which is 3.5 tera, or trillion (1012), electronvolt (TeV).

4. Indian scientists have made major contributions to GW physics over the past 25 years. In the late 1980s and early 1990s, Bala Iyer’s group at the Raman Research Institute (RRI), Bengaluru, in collaboration with a group of French scientists, pioneered the mathematical calculations used to model the GW signals expected from orbiting black holes and neutron stars. These calculations, using the so-called post-Newtonian methods, form the basis for computing the theoretical “templates” of the expected signals employed in GW detection.

5. A team of Indian scientists studying ancient rock art discovered in present-day Kashmir has stumbled upon what it believes could be the first-ever depiction of a supernova, an exploding supergiant star.

The carving on a stone slab measuring 48 cm by 27 cm was discovered many decades ago in Burzahom—a settlement that dates back to circa 4100 BCE—in the Kashmir valley.

The carving depicts what at first glance appear to be hunters and animals beneath a sky with not one but two bright sun-like objects. Now, the researchers led by Mayank Vahia, an astrophysicist with the Mumbai-based Tata Institute of Fundamental Research, have reinterpreted the depiction to argue that one of the bright objects shown in the carving could be a supernova.