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Subject: Basic Sciences

  • National Hydrogen Mission

    During his I-Day speech, the PM has announced a National Hydrogen Mission and said India will become the world’s largest exporter of green hydrogen in the years to come.

    National Hydrogen Mission

    • The PM’s announcement takes forward the proposal, made in the 2021 Budget, for the launch of NHM that would enable the generation of hydrogen “from green power sources”.
    • The added advantage of hydrogen is that, apart from transportation, it can be a “decarbonizing agent” for industries like chemicals, iron, steel, fertilizer and refining, transport, heat and power.
    • While the details of the NHM are yet to emerge, India has taken several exploratory steps.
    • India has been working on a pilot project on Blue Hydrogen, Hydrogen CNG (H-CNG), and Green Hydrogen.
    • Several programs are focusing to blend hydrogen with compressed natural gas for use as a transportation fuel as well as an industrial input to refineries.

    Hydrogen as a fuel

    • Hydrogen is the fuel of stars and packs awesome energy. It is also the most abundant element in the universe.
    • But on Earth, it is found in complex molecules such as water or hydrocarbons.
    • Hydrogen is not a source of energy, like fossil fuels or renewable sources like sunlight and air, but an energy carrier, which means it has to be produced, or extracted, and stored before it can be used.
    • But no matter how it is used, the by-product the burning of hydrogen produces is water.

    How is Hydrogen produced?

    • There are several ways of extracting hydrogen and, depending on the method, the hydrogen produced is classified as ‘grey’, ‘blue’, or ‘green’ hydrogen.
    • According to WEC, as of 2019, 96 percent of hydrogen is produced from fossil fuels via carbon-intensive processes.
    • Hydrogen thus obtained is called ‘grey’ hydrogen as the process, though not as expensive as the other methods, releases a lot of carbon dioxide.

    What Is Grey, Blue, Green Of Hydrogen?

    • ‘Grey’ hydrogen becomes ‘blue’ hydrogen when the CO2 given out during its production is locked up through carbon capture and storage (CCS) processes.
    • But while the CO2 output is lowered, this process is quite expensive.
    • ‘Grey’ and ‘blue’ hydrogen, thus, are both produced by the same processes, the only difference for ‘blue’ hydrogen being that the CO2 produced is sequestered.
    • But it is ‘green’ hydrogen that governments are aiming at. This is any hydrogen that is produced from clean energy sources like renewables.
    • ‘Green’ hydrogen is released via the electrolysis of energy from renewable sources. This process, though it gives rise to no CO2 emissions, is expensive and not commercially viable yet.

    Key challenges

    • Lack of infrastructure:  India does not have enough storage capacity for the current state of domestic consumption.
    • Safety concerns: Hydrogen is highly inflammable.

    Way ahead

    • Developing technologies to produce ‘green’ hydrogen is cost-intensive.
    • However, falling renewable energy and fuel cell prices and stringent climate change requirements have provided an impetus for investments in this area.
    • In India, the IITs, IISc, Benaras Hindu University, Council for Scientific and Industrial Research laboratories etc. are exploring different aspects of hydrogen production.

    UPSC 2022 countdown has begun! Get your personal guidance plan now! (Click here)

    Also read:

    [Burning Issue] India’s push for a Gas-based Economy

  • What is Absorption Spectroscopy?

    Researchers from IIT Madras and IISER Kolkata have developed a method to detect minute quantities of chemicals in solution using Absorption Spectroscopy.

    Note: These days there has been a rise in questions from biology (rather cell biology in particular).

    Absorption Spectroscopy

    • Absorption spectroscopy is a tool to detect the presence of elements in a medium.
    • Light is shone on the sample, and after it passes through the sample is examined using a spectroscope.
    • Dark lines are seen in the observed spectrum of the light passed through the substance, which correspond to the wavelengths of light absorbed by the intervening substance and are characteristic of the elements present in it.
    • In usual methods, about a cubic centimeter of the sample is needed to do this experiment.
    • In the method developed here, minute amounts of dissolved substances can be detected easily.
    • Usually in absorption spectroscopy, the principle used is that light because of its wavelike nature, shows diffraction patterns, that is, dark and light fringes, when it scatters off any object.

    Studying small objects

    • A related concept called the Abbe criterion sets a natural limit on the size of the object being studied.
    • According to this criterion, the size of the observed object has to be at least of the order of the wavelength of the light being shone on it.
    • If one wants to perform absorption spectroscopy using visible light, namely, blue, green and red, the wavelengths [of these colours] are about 400 nm, 500 nm and 600 nm, respectively.

    What has Indian researchers achieved?

    • In the method used by the researchers here, tiny, nano-sized particles that can absorb light being shone on them and re-emit red, blue and green light were employed.
    • The particles emit electric fields that are analogous to how a tiny magnet would give off magnetic lines of force – this is called a dipole, and the particle is like a tiny mobile phone’s antenna.
    • This dipole generates an electromagnetic field depending upon the quantum properties of the erbium dopants in the glass.
    • The absorption leaves a gap in the reflected light, which is what is observed and used to analyse the nature of the absorbing material.

    Applications of this technology

    • There are many potential applications.
    • Small molecules almost ten-millionth of an mm in diameter can be detected while these pass the emission region of the glass particle.
    • The future is to use it to measure individual molecules, see absorption spectroscopy of a single DNA or protein molecule.

    Try this

    Q.Which of the following statements are correct regarding the general difference between plant and animal cells?

    1. Plant cells have cellulose cell walls whilst animal cells do not.
    2. Plant cells do not have plasma membranes unlike animal cells which do.
    3. Mature plant cell has one large vacuole whilst an animal cell has many small vacuoles.

    Select the correct answer using the code given below:

    (a) 1 and 2 only

    (b) 2 and 3 only

    (c) 1 and 3 only

    (d) 1, 2 and 3

    [wpdiscuz-feedback id=”zkyreycvm5″ question=”Please leave a feedback on this” opened=”1″]Answer this PYQ here: [/wpdiscuz-feedback]

  • What is Retractable Roof Polyhouse?

    The CSIR-CMERI has recently inaugurated a “naturally ventilated polyhouse facility” and laid the foundation stone of “retractable roof polyhouse”.

    What is a Polyhouse?

    • A polyhouse is a specially constructed structure like a building where specialized polythene sheet is used as a covering material under which crops can be grown in partially or fully controlled climatic conditions.
    • It is covered with a transparent material as to permit the entry of natural light. Polyhouses are also helpful in reducing threats such as extreme heat and pest attacks in crops.
    • This is especially important for crops growing in the open field with no protection from the weather, and therefore its yield, quality, and crop maturity timings are changed.

    Retractable Roof Polyhouse

    • The retractable roof system is a modular screen system for greenhouses that helps in saving costs and time along with providing stability, flexibility & durability for the greenhouse structure.
    • Such polyhouse will have an automatic retractable roof which will be operated based on weather conditions and crop requirements from the conditional database using the software.

    Advantages offered

    • Ability to use the benefits of natural weather conditions
    • Long life of the system and material used
    • Easy assembly and installation
    • Maximum insulation and complete protection from insecticides
    • Easy maintenance & even easier repair work during operation

    Why need such polyhouse?

    • With rapidly rising temperatures due to mounting greenhouse gases in the atmosphere from human activities, crops are increasingly facing both threats — extreme heat and pest attacks — simultaneously.
    • Crop losses in India due to insect pests are about 15 percent at present and this loss may increase as climate change lowers the plant defense system against insects and pests.
    • Conventional greenhouses have a stationary roof to reduce the effect of weather anomalies and pests.
    • However, there are still disadvantages due to roof covering which sometimes lead to excessive heat and insufficient light (early morning).
    • Besides this, they are also prone to insufficient levels of carbon dioxide, transpiration, and water stress.

  • [pib] Near-Surface Shear Layer (NSSL) of Sun

    Indian astronomers have found a theoretical explanation for the existence of the Near-Surface Shear Layer (NSSL) of the Sun for the first time.

    What is a Near-Surface Shear Layer?

    • It was long known the Sun’s equator spins faster than the poles.
    • However, a peek into the internal rotation of the Sun using sound waves revealed the existence of an intriguing layer where the rotation profile of the Sun changes sharply.
    • The layer is called as a near-surface shear layer (NSSL), and it exists very close to the solar surface, where there is an outward decrease in angular velocity.

    What have researchers found?

    • They have used an equation called the thermal wind balance equation to explain how the slight difference in temperature between solar poles and equator, called thermal wind term.
    • It is balanced by the centrifugal force appearing due to solar differential rotation.
    • They have noted that if this condition is true near the solar surface, it can explain the existence of NSSL, which is inferred in helioseismology (technique of using sound waves to peek inside the Sun) based observation.

    Why study NSSL?

    • Understanding NSSL is crucial for the study of several solar phenomena like sunspot formation, solar cycle, and it will also help in understanding such phenomena in other stars.

  • Why does Mercury have such a big iron core?

    Researchers have developed a model showing that the density, mass and iron content of a Mercury’s core is influenced by its distance from the Sun’s magnetic field.

    About Mercury

    • Mercury is the first and the smallest planet in our solar system.
    • It is also the closest planet to Earth.
    • Like the other three terrestrial planets, Mercury contains a core surrounded by a mantle and a crust.
    • But unlike any other planet, Mercury’s core makes up a larger portion of the planet.
    • MESSENGER was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury’s chemical composition, geology, and magnetic field.
    • It was the analysis from the MESSENGER mission that tells: Mercury’s core is solid.

    Mystery over the core

    • It has long been known that Mercury’s core composition is made of liquid metal.
    • The core itself is about 3,600 km across. Surrounding that is a 600 km thick mantle.
    • And around that is the crust, which is believed to be 100-200 km thick.
    • The crust is known to have narrow ridges that extend for hundreds of kilometres.
    • This large core has long been one of the most intriguing mysteries about Mercury.

    Why does Mercury have a large core?

    • A new study reveals that the sun’s magnetism is the reason.
    • The sun’s magnetic field influences the density, mass, and iron content of Mercury’s core.
    • The four inner planets of our solar system—Mercury, Venus, Earth, and Mars—are made up of different proportions of metal and rock.
    • A gradient in which the metal content in the core drops off as the planets get farther from the sun.
    • The researchers explain how this happened by showing that the sun’s magnetic field controlled the distribution of raw materials in the early forming solar system.

    What are the key propositions?

    • During the early formation of the solar system, when a swirling dust storm and gas encircled the sun, iron’s grain was drawn toward the centre by the sun’s magnetic field.
    • At the time of planet formation from clumps of that dust and gas, planets nearer to the sun consolidated more iron into their centres than those farther away.
    • Scientists also found that the density and proportion of iron in the planet’s core correlate with the strength of the magnetic field around the sun during planetary formation.
    • Existing models on planetary formation were used to determine the speed at which gas and dust were pulled into the centre of our solar system during its formation.
    • The magnetic field that the sun would have generated as it burst into being and calculated how that magnetic field would draw iron through the dust and gas cloud.

    Cooling led solidification

    • As the early solar system began to cool, dust and gas that were not drawn into the sun started to clump together.
    • The clumps closer to the sun would have been exposed to a stronger magnetic field and thus would contain more iron than those farther away from the sun.
    • As the clumps coalesced and cooled into spinning planets, gravitational forces drew the iron into their core.

  • What are Doppler Radars?

    The India Meteorological Department’s (IMD) Doppler Radar in Mumbai, which surveys weather patterns and forecasts, stopped working after heavy rainfalls.

    How does a Doppler radar work?

    • In radars, a beam of energy– called radio waves– is emitted from an antenna.
    • When this beam strikes an object in the atmosphere, the energy scatters in all directions, with some reflecting directly back to the radar.
    • The larger the object deflecting the beam, the greater is the amount of energy that the radar receives in return.
    • Observing the time required for the beam to be transmitted and returned to the radar allows weather forecasting departments to “see” raindrops in the atmosphere, and measure their distance from the radar.

    What makes a Doppler radar special?

    • It can provide information on both the position of targets as well as their movement.
    • It does this by tracking the ‘phase’ of transmitted radio wave pulses; phase meaning the shape, position, and form of those pulses.
    • As computers measure the shift in phase between the original pulse and the received echo, the movement of raindrops can be calculated.
    • Thus it is possible to tell whether the precipitation is moving toward or away from the radar.

    Types of Doppler radar

    • In India, Doppler radars of varying frequencies — S-band, C-band and X-band — are commonly used.
    • They help track the movement of weather systems and cloud bands and gauge rainfall over its coverage area of about 500 km.
    • The radars guide meteorologists, particularly in times of extreme weather events like cyclones and associated heavy rainfall.
    • An X-band radar is used to detect thunderstorms and lightning whereas C-band guides in cyclone tracking.

    Why are they called ‘Doppler’ radars?

    • The phase shift in these radars works on the same lines as the “Doppler effect” observed in sound waves.
    • It tells that the sound pitch of an object approaching the observer is higher due to the compression of sound waves (a change in their phase).
    • As this object moves away from the observer, the sound waves stretch, resulting in lower frequency.
    • This effect explains why an approaching train’s whistle sounds louder than the whistle when the train moves away.
    • The discovery of the phenomenon is attributed to Christian Doppler, a 19th-century Austrian physicist.

  • What is UV-C technology?

    The Union Ministry for Science and Technology has informed that Ultraviolet-C or UV-C Disinfection Technology will soon be installed in Parliament for the mitigation of airborne transmission of SARS-COV-2.

    UV-C air duct disinfection system

    • The UV-C air duct disinfection system was developed by CSIR-CSIO (Central Scientific Instruments Organisation).
    • The system is designed to fit into any existing air-ducts and the virucidal dosages using UV-C intensity and residence time can be optimized according to the existing space.
    • The release adds that the virus is deactivated in any aerosol particles by the calibrated levels of UV-C light. It can be used in auditoriums, malls, educational Institutions, AC buses, and railways.

    What is Ultraviolet (UV)?

    • Ultraviolet (UV) is a type of light or radiation naturally emitted by the Sun. It covers a wavelength range of 100-400 nm. The human visible light ranges from 380–700 nm.
    • UV is divided into three bands: UV-C (100-280 nm), UV-B (280-315 nm) and UV-A (315-400 nm).
    • UV-A and UV-B rays from the Sun are transmitted through our atmosphere and all UV-C is filtered by the ozone layer.
    • UV-B rays can only reach the outer layer of our skin or epidermis and can cause sunburns and are also associated with skin cancer.
    • UV-A rays can penetrate the middle layer of your skin or the dermis and can cause ageing of skin cells and indirect damage to cells’ DNA.
    • UV-C radiation from man-made sources has been known to cause skin burns and eye injuries.

    So, can UV-C kill coronavirus?

    • UV-C radiation (wavelength around 254 nm) has been used for decades to disinfect the air in hospitals, laboratories, and also in water treatment.
    • But these conventional germicidal treatments are done in unoccupied rooms as they can cause health problems.
    • It can destroy the outer protein coating of the SARS-Coronavirus.

    Is it safe for humans?

    • The device is specifically developed to disinfect non-living things.
    • UV-C radiation used in this device could be harmful to the skin and eyes of living beings.

    Answer this PYQ in the comment box:

    Q.What is the role of ultraviolet (UV) radiation in the water purification systems?

    1. It inactivates/kills the harmful microorganisms in water.
    2. It removes all the undesirable odours from the water.
    3. It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of water.

    Which of the statements given above is/are correct? (CSP 2010)

    (a) 1 only

    (b) 2 and 3 only

    (c) 1 and 3 only

    (d) 1, 2 and 3

  • What is lightning, and how does it strike?

    With the monsoon making a slow revival over several parts of India, except the northwest region, there is a rise in lightning-linked deaths.

    What is lightning?

    • Lightning is a very rapid — and massive — discharge of electricity in the atmosphere, some of which is directed towards the Earth’s surface.
    • These discharges are generated in giant moisture-bearing clouds that are 10-12 km tall.
    • The base of these clouds typically lies within 1-2 km of the Earth’s surface, while their top is 12-13 km away.
    • Temperatures towards the top of these clouds are in the range of minus 35 to minus 45 degrees Celsius.

    How does it strike?

    • As water vapour moves upward in the cloud, the falling temperature causes it to condense.
    • Heat is generated in the process, which pushes the molecules of water further up.
    • As they move to temperatures below zero degrees Celsius, the water droplets change into small ice crystals. They continue to move up, gathering mass — until they are so heavy that they start to fall to Earth.
    • This leads to a system in which, simultaneously, smaller ice crystals are moving up and bigger crystals are coming down.
    • Collisions follow and trigger the release of electrons — a process that is very similar to the generation of sparks of electricity.
    • As the moving free electrons cause more collisions and more electrons, a chain reaction ensues.
    • This process results in a situation in which the top layer of the cloud gets positively charged, while the middle layer is negatively charged.

    Making of the thunder

    • The electrical potential difference between the two layers is huge — of the order of a billion to 10 billion volts.
    • In very little time, a massive current, of the order of 100,000 to a million amperes, starts to flow between the layers.
    • An enormous amount of heat is produced, and this leads to the heating of the air column between the two layers of the cloud.
    • This heat gives the air column a reddish appearance during lightning. As the heated air column expands, it produces shock waves that result in thunder.

    How does this current reach the Earth from the cloud?

    • While the Earth is a good conductor of electricity, it is electrically neutral.
    • However, in comparison to the middle layer of the cloud, it becomes positively charged.
    • As a result, about 15%-20% of the current gets directed towards the Earth as well.
    • It is this flow of current that results in damage to life and property on Earth.
    • There is a greater probability of lightning striking tall objects such as trees, towers or buildings.
    • Once it is about 80-100 m from the surface, lightning tends to change course towards these taller objects.
    • This happens because air is a poor conductor of electricity, and electrons that are travelling through air seek both a better conductor and the shortest route to the relatively positively charged Earth’s surface.

    What precautions should be taken against lightning?

    • Lightning rarely hits people directly — but such strikes are almost always fatal.
    • People are most commonly struck by what are called “ground currents”.
    • The electrical energy, after hitting a large object (such as a tree) on Earth, spreads laterally on the ground for some distance, and people in this area receive electrical shocks.
    • It becomes more dangerous if the ground is wet (which it frequently is because of the accompanying rain), or if there is metal or other conducting material on it.
    • Water is a conductor, and many people are struck by lightning while standing in flooded paddy fields.
    • For the reasons given above, taking shelter under a tree is dangerous. Lying flat on the ground too can increase risks.
    • People should move indoors in a storm; however, even indoors, they should avoid touching electrical fittings, wires, metal, and water.

    Answer this PYQ in the comment box:

    Q.During a thunderstorm, the thunder in the skies is produced by the:

    1. meeting of cumulonimbus clouds in the sky
    2. lightning that separates the nimbus clouds
    3. violent upward movement of air and water particles

    Select the correct option using the codes given below (CSP 2011):

    (a) 1 only

    (b) 2 and 3 only

    (c) 1 and 3 only

    (d) None of the above

  • What is a Bitcoin Hardware Wallet and how it works?

    Last week, Twitter CEO announced his payments firm Square would soon build a hardware wallet to store bitcoin.

    Bitcoin Hardware Wallet

    • The wallet will be a type of plug-in device, much like a USB pen drive that stores, manages and secures a user’s crypto assets.
    • Each digital asset is linked to a cryptographic password called a ‘private key’ to allow users to access it.
    • This key safeguards cryptocurrencies from theft and unauthorized access.
    • The asset owner, with the help of a secure hardware wallet, can access the private key to buy and sell crypto assets from anywhere.
    • Most hardware wallets allow users to manage multiple accounts; some even allow users to connect to their Google or Facebook accounts.
    • Popular hardware wallets include Trezor, Ledger, KeepKey and Prokey.

    How is it different from a software wallet?

    • Cryptocurrency keys can be stored in two kinds of wallets – software and hardware.
    • Software wallets are like smartphone apps that digitally store private keys.
    • Most software wallets don’t charge users to store private keys but may collect a commission for trading via the app.
    • These wallets can be vulnerable to malware.
    • Hardware wallets and physical devices act like cold storage for confidential keys. The passwords are protected by a PIN, making it difficult for hackers to extract private keys as the information is not exposed to the Internet.

    The upsides of a hardware wallet

    • Hardware wallets are said to be convenient as they can be connected to trading exchanges to complete transactions.
    • Hardware wallets are often stored in a protected microcontroller and cannot be transferred out of the device, making them secure.
    • Their isolation from the Internet also mitigates the risk of the assets being compromised. Moreover, it does not rely on any third-party app.

    Limitations

    • Since the wallet is in physical form, the device could be stolen or destroyed.
    • They could be used by malicious actors to steal confidential data.
    • The device can also be expensive as compared to software wallets.
    • Some hardware wallets can also have complex features, making it difficult for first-timers to understand.

    Answer this PYQ in the comment box:

    Q.With reference to “Blockchain Technology”, consider the following statements:

    1. It is a public ledger that everyone can inspect but which no single user controls.
    2. The structure and design of block chain is such that all the data in it are about crypto currency only.
    3. Applications that depend on basic features of blockchain can be developed without anybody’s permission.

    Which of the statement given above is/are correct?

    (a) 1 only

    (b) 2 only

    (b) 1 and 2 only

    (d) 1 and 3

    Back2Basics: Cryptocurrencies

    • A cryptocurrency is a digital asset designed to work as a medium of exchange wherein individual coin ownership records are stored in a ledger existing in a form of a computerized database.
    • It uses strong cryptography to secure transaction records, control the creation of additional coins, and verify the transfer of coin ownership.
    • It typically does not exist in physical form (like paper money) and is typically not issued by a central authority.
    • Cryptocurrencies typically use decentralized control as opposed to centralized digital currency and central banking systems.

  • 2020 Millennium Technology Prize  

    The 2020 Millennium Technology Prize has been awarded to Shankar Balasubramanian and David Klenerman, for their development of revolutionary Next-generation DNA sequencing techniques.

    About Millennium Technology Prize

    • The Millennium Technology Prize is one of the world’s largest technology prizes.
    • It is awarded once every two years by Technology Academy Finland, an independent fund established by Finnish industry and the Finnish state in partnership.

    What is next-generation DNA sequencing?

    • Next-generation sequencing (NGS) is a massively parallel sequencing technology that offers ultra-high throughput, scalability, and speed.
    • The technology is used to determine the order of nucleotides in entire genomes or targeted regions of DNA or RNA.
    • These technologies allow for sequencing of DNA and RNA much more quickly and cheaply than the previously used sequencing.
    • NGS has revolutionized the biological sciences, allowing labs to perform a wide variety of applications and study biological systems at a level never before possible.
    • More than a million base pairs can be sequenced, which translates to hundreds of genes or even the whole genome of an organism.
    • This is made possible by simultaneously sequencing hundreds of pieces of DNA at the same time.

    What is sequencing, btw?

    • DNA (or RNA, in some viruses), the genetic material of life forms, is made of four bases (A, T, G and C; with U replacing T in the case of RNA).
    • A chromosome is the duplex of a long linear chain of these – and in the DNA sequence is information – the blueprint of life.
    • Life famously can replicate, and DNA replicates when an enzyme, DNA polymerase, synthesises a complementary strand using an existing DNA strand as the template.
    • The breakthrough idea of Balasubramanian and Klenerman was to sequence DNA (or RNA) using this process of strand synthesis.
    • They cleverly modified their ATGC bases so that each shone with a different colour.
    • When copied, the “coloured” copy of DNA could be deciphered from the colours alone, using miniature optical and electronic devices.

    What about the cost of all this sequencing?

    • When the Human Genome Project delivered the first, near-complete sequence of our genome, the cost was estimated to have been 3 billion dollars.
    • As all our chromosomes together have 3 billion base pairs, it becomes an easy calculation – One dollar per sequenced base.
    • By the year 2020, NGS technologies has pushed the price for sequencing to a few thousands of rupees.

    Back2Basics:

    What is the Human Genome Project?