Science Monitor: 29 August 2020
Science Monitor: 29 August 2020
1. Indian satellite AstroSat discovers one of the earliest galaxies of Universe
India’s first multi-wavelength space observatory AstroSat has outperformed Hubble Space Telescope by detecting extreme ultraviolet light eminating from a galaxy about 9.3 billion light years away from Earth. The breakthrough discovery was made by Dr. Kanak Saha of Inter-University Centre for Astronomy and Astrophysics, Pune and his team comprising of National and International Astronomers. According to the scientist, the discovery is crucial for understanding the reionization of cosmos.
About the galaxies:
- Indian space observatory AstroSat has discovered one of the primitive galaxies called AUDFs01. The major breakthrough is the result of an in-depth study by a global team of Astronomers led by Prof. Kanak Saha of IUCAA.
- The team has scientists from India, Switzerland, France, USA, Japan and the Netherland. The astronomers observed galaxy for nearly 28 hours on October, 2016 and the data was carefully analysed for the next two years to ascertain that the emission was indeed from the galaxy called AUDFs01, which is located 9.3 billion light years away from the Earth.
- Astronomers have been looking for the first sources that reionize the early universe, but observing ionizing radiation from the sources is next to impossible, because these photons get absorbed by the gas in the galaxy or the matter between the galaxy and Earth.
- NASA placed Hubble Space Telescope to discover such radiation in space, but it could not detect this emission, although it is much larger than the Astrosat’s UltraViolet Imaging Telescope (UVIT). Therefore, this is a unique achievement by Indian space observatory AstroSat.
- AstroSat was launched on 28th September 2015 by the ISRO. It has the 38 cm diameter, UVIT onboard, which is capable of simultaneous imaging in far and near ultraviolet bands with a wide field of view. It has helped in detection of AUDFs01 is in the middle of red shift range, where previously no similar sources were detected.
- According to astronomers, it is also the beginning of new exploration of star forming galaxies at extreme UV wavelength. The discovery has been published in the journal ‘Nature Astronomy’.
2. ARCI developed high-performance tin anodes for lithium-ion battery used in Electric Vehicles
To make electric vehicles a viable option of transport, there is a need to develop stable and fast charging batteries. To cater to this need Chennai based centre of ARCI, an autonomous institute under the Department of Science and Technology has developed a unique technology to transform commercially available micron sized tin into high performance anode material for lithium-ion batteries that are used in electric vehicles. The tin anodes are fabricated by this method are also very low cost.
About this technology:
- The use of electric vehicles is now being encouraged to save the environment. All electric vehicles such as Cars, Scooters and Public transport make use of lithium-ion batteries, but the capacity of batteries and their need for charging at regular intervals is a major hindrance in the use of these vehicles.
- Scientists at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI) have now developed a solution for this problem. Located at the research park of the IIT Madras, ARCI, Chennai Centre or Automotive Energy Materials has developed low cost micron tin based anodes, which proved to be high performance and stable anode material for lithium-ion batteries (LIBs). These anodes will increase lifecycle and charging capability of batteries.
- The conventional lithium-ion batteries used graphite as an anode as it has minimal volume expansion of 12 percent during charge/discharge cycle. But these batteries suffer from moderate capacity and limited fast charging capability.
- Commercially available tin with its low cost high capacity and fast charging capability can replace graphite, but it has a major drawback of high volume expansion during charge/discharge cycle, which leads to cracking of electrodes. To solve this problem ARCI Chennai scientists have developed a unique technology with which high performance and stable anodes can be fabricated using commercially available micron tin.
- The technology involves noble and harmless binder which establishes multidimensional contact points with the tin particles and acts as a buffer against high volume expansion.
- This technology gives results as good as using nano tin for anodes. The study has been published in the journal ‘Energy Technology’.
- Apart from electric vehicles these batteries can also be used for various other applications. The method will not only reduce the cost of the battery but also improve their cycle life and charging capability. Such batteries will give a push to the electric vehicles sector and make electric vehicles more users friendly.
3. Centre for Nano and Soft Matter Sciences has developed an invisible and flexible electromagnetic interference shield using Copper metal mesh
For uninterrupted use of electronic devices or systems, it is very important to save them from electromagnetic interference or EMI and when such system are used in critical applications like medical and defence, then it becomes all the more important to save them from EMI. Traditionally opaque metal films have been used as shields to solve this problem, but now Bengaluru based Centre for Nano and Soft Matter Sciences (CeNS) has developed an invisible and flexible EMI shields using copper metal mesh.
About the EMI shield:
- While using TV, Radio, Cell phone or Internet, we all have encountered at some point of time a disturbance in sound, picture or a sudden loss of contact. This happens due to the radio frequency interference or electromagnetic interference also known as EMI.
- It is basically a disturbance that affects an electrical circuit when it comes in the vicinity of electromagnetic radiation from an external source. It is also used deliberately by security agencies to intercept radio or phone signals and is very common in radio broadcasting.
- Now, scientists of Bengaluru based Centre for Nano and Soft Matter Sciences, an an autonomous institute under the Department of Science and Technology, GoI have developed an invisible or transparent shield to protect electromagnetic wave emitter or observe a devices from EMI without compromising the transparency and aesthetics. The shield can be very useful for various military stealth applications like to hide fighter plane from radar signals.
- Usually, for EMI shielding a continuous film of metal coating is used, but it ceases or reduces the transparency of many materials. To overcome this problem, Scientists at CeNS made very fine copper metal mesh on polyethylene terephthalate or PET substrate.
- Using the Crack templating method with spray coating which maintains up to 85 percent transparency provides a better electromagnetic shielding. This metal mesh can be created on any desired substrates, such as polycarbonate or glass without compromising the conductivity of the electrodes.
- CeNS in collaboration with its industrial partner Hind high vacuum (HHV) Private Limited has also set up DST funded semi automated production plant for producing transparent conducting glasses for making transparent EMI shields. The innovation will satisfy the huge demand for highly effective transparent and flexible EMI shield.
4. Ground water crisis in Northwestern India
The Northwestern plain of India also known as the bread basket of India these plains are suffering from ground water crisis due to the over exploitation of ground water resources for irrigation purposes. To check this, the government of India targeted to improve the efficient use of ground water by 20 percent. Now a model based study anticipated the future trend of the ground water level in this area with and without the efficient use.
About the study:
- The Northwestern region of India has been catering to the tremendous food needs of the country, but inefficient irrigation practices, over exploitation of ground water resources and low ground water recharge have made it one of the largest centre of ground water degradation in the world.
- Recently, researchers from IIT, Kanpur, University of Delhi, BHU and National Geophysical Research Institute collaborated with the researchers of England based Durham University to conduct a study in the Northwestern India especially in Haryana and Punjab.
- The results of this study have revealed that the groundwater crisis in this region is getting more serious. The study shows that without any mitigation efforts, by the year 2028, the groundwater level will fall by about 28 metres in Kurushetra district of Haryana that is at the rate of 2.8 metres per year. Whereas, groundwater level in some part of Punjab and Haryana will decrease by 5 to 10 metre in the next decade.
- The study has used a calibrated and validated regional scale 3D ground water flow model to assess the groundwater decline under baseline scenario and mitigation scenario.
- According to the study, a reduction in groundwater abstraction by 20 per cent has the potential to generate a significant positive impact on groundwater level within a decade. It could retard the rate of groundwater decline by up to 67 percent in areas that are currently overexploited.
- Apparently, the use of groundwater was introduced to increase and stabilise agriculture produce, but excessive pumping has created a very critical situation. On the other hand change in rainfall pattern and Urbanisation have reduced the recharging capacity of groundwater.
- Therefore, agriculture water management practices incorporating groundwater use efficiency, water efficient cropping pattern and rain water harvesting for agricultural use is strongly needed to deter the impending groundwater crisis, combining such efforts can yield better results in a shorter period.