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Type: Prelims Only

  • 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.

  • Person in news: Abanindranath Tagore

    Year-long celebrations marking 150 years of Abanindranath Tagore have been kicked off in Kolkata.

    Abanindranath Tagore (1871-1951)

    • Tagore CIE was the principal artist and creator of the “Indian Society of Oriental Art”.
    • A nephew of Rabindranath Tagore and a decade younger to the poet, he helped shape modern Indian art and was the creator of the iconic ‘Bharat Mata’ painting.
    • He was also the first major exponent of Swadeshi values in Indian art, thereby finding the influential Bengal school of art, which led to the development of modern Indian painting.
    • He was also a noted writer, particularly for children.
    • Tagore sought to modernize Mughal, Rajput styles to counter the influence of Western models of art, as taught in art schools under the British Raj.
    • Along with other artists from the Bengal school of art, Tagore advocated in favor of a nationalistic Indian art derived from Indian art history, drawing inspiration from the Ajanta Caves.

    Q. Which among the following event happened earliest? (CSP 2018)

    (a) Swami Dayanand established Arya Samaj.

    (b) Dinabandhu Mitra wrote Neeldarpan.

    (c) Bankim Chandra Chattopadhyay wrote Anandmath.

    (d) Satyendranath Tagore became the first India to succeed in the Indian Civil Services Examination.

    [wpdiscuz-feedback id=”g8kqy5pabf” question=”Please leave a feedback on this” opened=”1″]Answer this PYQ in the comment box:[/wpdiscuz-feedback]

     

  • Indigenous Aircraft Carrier 1 (INS Vikrant)

    The much-awaited sea trials of India’s maiden indigenous aircraft carrier (IAC-1), built by the public sector Cochin Shipyard Ltd (CSL) have begun.

    Indigenous Aircraft Carrier 1

    • IAC is the first aircraft carrier designed and built in India.
    • It has been designed by the Indian Navy’s Directorate of Naval Design (DND), and is being built at Cochin Shipyard Limited (CSL), a public sector shipyard under the Ministry of Shipping.
    • The IAC-1, the biggest warship made indigenously, has an overall length of 263 m and a breadth of 63 m.
    • It is capable of carrying 30 assorted aircraft including combat jets and helicopters.
    • Propelled by four gas turbines, it can attain a top speed of 30 knots (about 55 kmph).
    • The vessel will have a complement of 1,500 personnel.

    Significance of IAC 1

    • An aircraft carrier is one of the most potent marine assets for a nation, which enhances a Navy’s capability to travel far from its home shores to carry out air domination operations.
    • Many experts consider having an aircraft carrier as essential to be considered a ‘blue water’ navy — one that has the capacity to project a nation’s strength and power across the high seas.
    • An aircraft carrier generally leads as the capital ship of a carrier strike/battle group.
    • As the carrier is a valuable and sometimes vulnerable target, it is usually escorted in the group by destroyers, missile cruisers, frigates, submarines, and supply ships.

    Why does it matter that this is a Made-in-India warship?

    • Only five or six nations currently have the capability of manufacturing an aircraft carrier — India joins this elite club now.
    • According to the Navy, over 76 per cent of the material and equipment on board IAC-1 is indigenous.
    • India’s earlier aircraft carriers were either built by the British or the Russians.
    • The INS Vikramaditya, currently the Navy’s only aircraft carrier that was commissioned in 2013, started out as the Soviet-Russian Admiral Gorshkov.
    • The country’s two earlier carriers, INS Vikrant and INS Viraat, were originally the British-built HMS Hercules and HMS Hermes before being commissioned into the Navy in 1961 and 1987 respectively.

    Why will this warship be named INS Vikrant?

    • INS Vikrant, a Majestic-class 19,500-tonne warship, was the name of India’s much-loved first aircraft carrier, a source of immense national pride over several decades of service before it was decommissioned in 1997.
    • India acquired the Vikrant from the United Kingdom in 1961, and the carrier played a stellar role in the 1971 war with Pakistan that led to the birth of Bangladesh.

    Now that India has the capability, will it build more carriers?

    • Since 2015, the Navy has been seeking approval to build a third aircraft carrier for the country, which, if approved, will become India’s second Indigenous Aircraft Carrier (IAC-2).
    • This proposed carrier, to be named INS Vishal, is intended to be a giant 65,000-tonne vessel, much bigger than IAC-1 and the INS Vikramaditya.
    • The Navy has been trying to convince the government of the “operational necessity” of having a third carrier.

  • Strategic Petroleum Reserves

    Under Phase II of the petroleum reserve program, the Government has approved two additional commercial-cum-strategic facilities at Chandikhol (Odisha) and Padur (TN) on Public-Private Partnership (PPP) model.

    Strategic Petroleum Reserves Programme

    • To ensure energy security, the govt had decided to set up 5 million metric tons (MMT) of strategic crude oil storage at three locations namely, Visakhapatnam, Mangalore, and Padur (near Udupi).
    • These strategic storages would be in addition to the existing storage of crude oil and petroleum products with the oil companies and would serve as a cushion during any supply disruptions.
    • The petroleum reserves established are strategic, and the crude oil stored in these reserves will be used during an oil shortage event, as and when declared so by the Government of India.
    • The construction of the Strategic Crude Oil Storage facilities is being managed by Indian Strategic Petroleum Reserves Limited (ISPRL), a Special Purpose Vehicle.

    Why need SPR?

    • The Gulf War in 1990 caused a sharp rise in oil prices and a massive increase to India’s imports.
    • During the subsequent 1991 Indian economic crisis, foreign exchange reserves could barely finance three weeks’ worth of imports while the government came close to defaulting on its financial obligations.
    • India was able to resolve the crisis through policies that liberalized the economy. However, India continued to be impacted by the volatility of oil prices.
    • In 1998, the AB Vajpayee administration proposed building petroleum reserves as a long-term solution to managing the oil market.
    • Three storage facilities were built in underground locations in Mangalore, Visakhapatnam and Padur.

    Construction of ISPR

    • The crude oil storages are constructed in underground rock caverns and are located on the East and West coasts of India.
    • Crude oil from these caverns can be supplied to the Indian Refineries either through pipelines or through a combination of pipelines and coastal movement.
    • Underground rock caverns are considered the safest means of storing hydrocarbons.

  • NASA-ISRO Synthetic Aperture Radar

    The NASA-ISRO Synthetic Aperture Radar satellite, aimed at making global measurement of land surface changes using advanced radar imaging, is proposed to be launched in early 2023, informed Earth Sciences Minister.

    Note the key features of the Mission. Every statement has a unique information.

    NASA-ISRO SAR

    • NISAR is a joint collaboration for a dual-frequency L and S-band SAR for earth observation.
    • NASA and Bengaluru-headquartered ISRO signed a partnership on September 30, 2014, to collaborate on and launch NISAR.
    • The mission is targeted to launch in early 2022 from ISRO’s Sriharikota spaceport in Andhra Pradesh’s Nellore district, about 100km north of Chennai.
    • It is capable of producing extremely high-resolution images for a joint earth observation satellite mission with NASA.
    • It will be the first satellite mission to use two different radar frequencies (L-band and S-band) to measure changes in our planet’s surface less than a centimeter across.

    Objectives of the NISAR

    • NISAR will observe Earth’s land and ice-covered surfaces globally with 12-day regularity on ascending and descending passes, sampling Earth on average every six days for a baseline three-year mission.
    • It will measure Earth’s changing ecosystems, dynamic surfaces, and ice masses, providing information about biomass, natural hazards, sea-level rise, and groundwater, and will support a host of other applications.
    • It would also provide data on natural hazards including earthquakes, tsunamis, volcanoes, and landslides.

    What are L and S Bands?

    • L band waves are used for GPS units because they are able to penetrate clouds, fog, rain, storms, and vegetation.
    • The S-band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station.
    • NISAR uses a sophisticated information-processing technique known as SAR to produce extremely high-resolution images.
    • Radar penetrates clouds and darkness, enabling NISAR to collect data day and night in any weather.

    What is collaboration?

    • NASA is providing the mission’s L-band SAR, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder, and payload data subsystem.
    • ISRO is providing the spacecraft bus, the S-band radar, the launch vehicle, and associated launch services for the mission, whose goal is to make global measurements of the causes and consequences of land surface changes using advanced radar imaging.

  • Stellar Mid-life Crisis: What ails the middle-aged Sun?

    Stars like our Sun can go through a mid-life crisis, according to new research carried out by scientists from IISER Kolkata.

    Stellar Middle Age

    • At about 4.6 billion years of age, the sun is middle-aged, that is, it will continue to live for roughly the same period.
    • There are accurate methods for estimating the age of the Sun, such as by using radioactive dating of very old meteorites that have fallen on the Earth.
    • However, for more distant stars which are similar in mass and age to the Sun, such methods are not possible.
    • One of the methods used is called gyrochronology.
    • There is a relationship between rotation rate and age, that is the rotation rate of a star slows down with age.

    How does it occur?

    • When the stellar wind escapes from the star, it carries away with it a part of the angular momentum of the star, which results in its slowing down.
    • The stellar wind has two drivers: one is the high temperature of the outer atmosphere of stars – the corona – which results in an outward expansion and hence plasma winds that emanate out.
    • The other is the magnetic field.
    • The magnetic field actually heats the corona and so when magnetic activity is strong the winds are strong and since wind carries away the internal (rotational) angular momentum of the star, it slows down its rotation.
    • This is called magnetic braking.
    • As the star ages, due to this mechanism, its rotation slows down and this relationship is used in gyrochronology to estimate the age of the star.

    Impact

    • This can lead to dramatic changes in their activity and rotation rates.
    • The study also provides an explanation for the breakdown of the long-established relation between rotation rate and age in middle-aged sunlike stars.
    • However, there is a breakdown of the gyrochronology relationship, because, after midlife, a star’s rate of spin does not slow down with age as fast as it was slowing down earlier.
    • Another intriguing fact is that the Sun’s activity level has been observed to be much lower than other stars of similar age.

  • Geo-imaging satellite EOS-03

    Geo-imaging satellite for earth observation EOS-03, which would enable near real-time monitoring of natural disasters like floods and cyclones, is scheduled for launch in the third quarter of 2021.

    EOS-03

    • ISRO has realized a geo-imaging satellite, “EOS-03”, for Earth Observation from Geostationary Orbit.
    • EOS-03 is capable of imaging the whole country four-five times daily and would enable near real-time monitoring of natural disasters like floods and cyclones.
    • In addition to natural disasters, EOS-03 would also enable monitoring of water bodies, crops, vegetation condition, forest cover changes.

    Other developments: Small Satellite Launch Vehicle (SSLV)

    • The first developmental flight of the Small Satellite Launch Vehicle (SSLV) is scheduled for the fourth quarter of 2021 from the Satish Dhawan Space Centre, Sriharikota.
    • The SSLV is a cost-effective, three-stage and all-solid launch vehicle with a payload capability of 500 kg to 500 km planar orbit or 300 kg to Sun-Synchronous Polar Orbit.
    • It is ideal for the on-demand, quick turn-around launch of small satellites.
    • The major technologies developed as part of SSLV are flexible nozzle control with electro-mechanical actuators for all stages, miniaturized avionics, and a velocity trimming module in the upper stage for precise satellite injection.

  • Russia’s Nauka Module for ISS

    Pirs, a Russian module on the International Space Station (ISS) used as a docking port for spacecraft and as a door for cosmonauts to go out on spacewalks. In its place, Russia’s space agency Roscosmos will be attaching a significantly larger module called Nauka.

    What does Russia’s new Nauka module do?

    • Nauka, which is 42 feet long and weighs 20 tonnes, was supposed to be launched as early as 2007, as per the ISS’s original plan.
    • Nauka — meaning “science” in Russian — is the biggest space laboratory Russia has launched to date, and will primarily serve as a research facility.
    • It is also bringing to the ISS another oxygen generator, a spare bed, another toilet, and a robotic cargo crane built by the European Space Agency (ESA).
    • The new module was sent into orbit using a Proton rocket — the most powerful in Russia’s space inventory — on July 21 and will take eight days to reach the ISS.

    What kind of research goes on at the International Space Station?

    • A space station is essentially a large spacecraft that remains in low-earth orbit for extended periods of time.
    • It is like a large laboratory in space and allows astronauts to come aboard and stay for weeks or months to carry out experiments in microgravity.
    • For over 20 years since its launch, humans have continuously lived and carried out scientific investigations on the $150 billion ISS under microgravity conditions, being able to make breakthroughs in research not possible on Earth.

    Back2Basics: International Space Station (ISS)

    • The International Space Station, which launched its first piece in 1998, is a large spacecraft that orbits around the Earth and is home to the astronauts.
    • The ISS is currently the only active space station in the earth’s orbit.
    • The first crew on the space station arrived on November 2, 2000.
    • The space station is home to a minimum of six astronauts, with two bathrooms, a gymnasium, and a big bay window.
    • It is a joint project between five participating space agencies -NASA (USA), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada).

  • Thane Creek Flamingo Sanctuary proposed as Ramsar Site

    The Mumbai Metropolitan Region is likely to get its first Ramsar site at the Thane Creek Flamingo Sanctuary.

    Thane Creek Flamingo Sanctuary

    • The Maharashtra Government has declared the area along the western bank of Thane Creek as the “Thane Creek Flamingo Sanctuary” since 2015.
    • It is Maharashtra’s second marine sanctuary after the Malvan sanctuary.
    • It is recognized as an “Important Bird Area” by the Bombay Natural History Society.

    About Ramsar Convention

    • The Convention on Wetlands of International Importance (better known as the Ramsar Convention) is an international agreement promoting the conservation and wise use of wetlands.
    • It is the only global treaty to focus on a single ecosystem.
    • The convention was adopted in the Iranian city of Ramsar in 1971 and came into force in 1975.
    • Traditionally viewed as a wasteland or breeding ground of disease, wetlands actually provide fresh water and food and serve as nature’s shock absorber.
    • Wetlands, critical for biodiversity, are disappearing rapidly, with recent estimates showing that 64% or more of the world’s wetlands have vanished since 1900.
    • Major changes in land use for agriculture and grazing, water diversion for dams and canals, and infrastructure development are considered to be some of the main causes of loss and degradation of wetlands.

    What does one mean by Ramsar Site?

    • A Ramsar Site is a wetland area designated to be of international importance under the Ramsar Convention.
    • It provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.