UPSC Prelims Research: Science and Tech 2024

Q. Consider the following:

1. Battery storage
2. Biomass generators
3. Fuel cells
4. Rooftop solar photovoltaic units

How many of the above are considered “Distributed Energy Resources”?

(a) Only one
(b) Only two
(c) Only three
(d) All four

Answer: (d) All four

Distributed Energy Resources (DERs)

• Distributed Energy Resources (DERs) are small-scale energy systems that generate, store, and consume energy locally, often near the point of consumption.
• These resources are typically connected to the local distribution grid and can provide electricity, thermal energy, and/or mechanical energy.
• DERs can include renewable energy sources, energy storage systems, demand response technologies, and other energy-efficient devices.

Types of Distributed Energy Resources:

• Renewable Energy Systems:
  • i) Solar Photovoltaic (PV) Panels convert sunlight directly into electricity.
  • ii) Wind Turbines generate electricity from wind energy.
  • iii) Small-Scale Hydropower uses flowing water to generate electricity.
• Energy Storage Systems:
  • i) Batteries store excess electricity generated by renewable sources for later use.
  • ii) Thermal Storage stores heat or cold for later use, helping to balance supply and demand.
• Combined Heat and Power (CHP) Systems: It generate electricity and capture usable heat simultaneously, improving overall efficiency.
• Microgrids are localized grids that can disconnect from the traditional grid to operate autonomously, enhancing resilience.
• Demand Response Technologies are systems and programs that reduce or shift electricity usage during peak demand times.
• Electric Vehicles (EVs) can act as mobile energy storage units and provide power back to the grid when needed.

Benefits of DERs:

• Increased Resilience and Reliability: It enhance the reliability of the power grid by reducing dependence on large, centralized power plants. It improves grid resilience during extreme weather events or other disruptions.
• Environmental Benefits: It reduce greenhouse gas emissions by integrating more renewable energy sources. It decreases air pollution and reliance on fossil fuels.
• Cost Savings: It lowers electricity costs for consumers by reducing transmission losses and avoiding the need for expensive grid upgrades. It has potential for revenue generation through net metering and participation in energy markets.
• Energy Independence: It enhance energy security by diversifying energy sources and reducing reliance on imported fuels.
• Grid Modernization facilitate the transition to a smarter, more flexible, and decentralized energy grid.

Challenges of DERs:

• Integration and Coordination: Managing the intermittent nature of renewable energy sources, such as solar and wind, is crucial to ensure grid stability. Also, coordinating multiple DERs and integrating them into the existing grid infrastructure poses significant challenges.
• Regulatory and Policy Barriers: Navigating complex regulatory environments and ensuring the development of supportive policies for DER deployment are critical for their widespread adoption.
• Economic and Financial Considerations: High upfront costs for certain DER technologies necessitate financing solutions. Moreover, developing business models that incentivize the adoption and operation of DERs is essential for their economic viability.
• Technical Challenges: Ensuring the interoperability and communication between different DER systems is vital for their effective integration. Additionally, addressing cybersecurity risks associated with the increased digitalization of energy systems is a major concern.

Q. Which one of the following words/phrases is most appropriately used to denote “an interoperable network of 3D virtual worlds that can be accessed simultaneously by millions of users, who can exert property rights over virtual items”?

(a) Big data analytics

(b) Cryptography

(c) Metaverse

(d) Virtual matrix

Answer: (c) Metaverse

Metaverse:

• The term “metaverse” is widely used to describe an interoperable network of 3D virtual worlds.
• It encompasses virtual spaces where millions of users can interact, create, and exert property rights over virtual items. It is the most appropriate term for the given description.
• Technology:
  • Virtual Reality (VR): Creates immersive experiences.
  • Augmented Reality (AR): Overlays digital information on the physical world.
  • Blockchain: Enables digital ownership and decentralized transactions.
  • Artificial Intelligence (AI): Enhances interactions and personalizes experiences.
• Applications:
  • Gaming: Enhanced multiplayer experiences.
  • Social Interaction: Virtual meetups, events, and socializing.
  • Commerce: Virtual shopping, virtual real estate.
  • Education: Immersive learning environments and virtual classrooms.
  • Work: Virtual offices and remote collaboration.

Big Data Analytics:

• Big data analytics: This term refers to the process of examining large and varied data sets to uncover hidden patterns, unknown correlations, market trends, customer preferences, and other useful information.
• Big data analytics allows for the uncovering of trends, patterns and correlations in large amounts of raw data to help analysts make data-informed decisions. This process allows organizations to leverage the exponentially growing data generated from diverse sources, including internet-of-things (IoT) sensors, social media, financial transactions and smart devices to derive actionable intelligence through advanced analytic techniques.
  • It is not related to 3D virtual worlds or property rights over virtual items.

Cryptography:

• Cryptography: Cryptography involves the practice of secure communication in the presence of third parties.
• It involves creating written or generated codes that allow information to be kept secret.
• Types of Cryptography:
  • Symmetric-Key Cryptography
    • Description: Uses the same key for both encryption and decryption.
    • Examples: DES (Data Encryption Standard), AES (Advanced Encryption Standard).
  • Asymmetric-Key Cryptography
    • Description: Uses a pair of keys – a public key for encryption and a private key for decryption.
    • Examples: RSA (Rivest-Shamir-Adleman), ECC (Elliptic Curve Cryptography).
• Key Concepts in Cryptography:
  • Encryption: The process of converting plain text into coded text to prevent unauthorized access.
  • Decryption: The process of converting coded text back into plain text using a key.
  • Hash Functions: Produce a fixed-size hash value from input data of any size. They are used for ensuring data integrity.
  • Digital Signatures: Provide authenticity and integrity to digital messages by combining hashing and asymmetric cryptography.

Virtual Matrix:

• Virtual Matrix: While this term suggests a structured and interconnected system of virtual environments. It generally refers to a technology or system that allows for the control and display of video or data across multiple monitors or displays as if they were part of a physical matrix.
  • This is often used in surveillance systems, data visualization, and communication software.

Q. With reference to radioisotope thermoelectric generators (RTGs), consider the following statements :

1. RTGs are miniature fission reactors.
2. RTGs are used for powering the onboard systems of spacecrafts.
3. RTGs can use Plutonium-238, which is a by-product of weapons development.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (b) 2 and 3 only

Radioisotope thermoelectric generators (RTGs):

• Radioisotope thermoelectric generators (RTGs) are power sources that convert the heat released by radioactive decay into electricity. They are commonly used in space missions to power spacecraft, especially in deep space where solar power is insufficient.
• RTGs work by using radioactive materials like plutonium-238 or Strontium-90, which naturally decay and emit heat. This heat is then converted into electricity through thermocouples.
• RTGs are usually the most desirable power source for unmaintained situations that need a few hundred watts (or less) of power for durations too long for fuel cells, batteries, or generators to provide economically, and in places where solar cells are not practical.
• Sometimes referred to as “nuclear batteries,” RTGs are not fission reactors, nor is the plutonium the type that is used for nuclear weapons.
• Applications:
  • RTGs are used in a variety of space missions, including:
    • Interplanetary probes: Voyager 1 and 2, Cassini, and New Horizons.
    • Lunar missions: Apollos 12 and 14-17, China’s Chang’e landers.
    • Martian rovers: Viking 1 and 2, Curiosity.
• Advantages:
  • Long-lasting power: RTGs can provide reliable power for decades, making them ideal for long-duration missions.
  • No moving parts: This simplifies their design and increases their reliability, as they are less prone to mechanical failure.
  • Independence from solar power: RTGs can provide power in areas with low or no sunlight, such as deep space or shadowed regions of planets.
• Disadvantages:
  • Radioactive material: The use of radioactive material raises safety concerns, especially during launch and reentry.
  • Cost: RTGs are generally more expensive than other power sources, such as solar panels.
  • Heat dissipation: RTGs generate a significant amount of heat, which needs to be managed to prevent overheating and damage to the surrounding components.

Q. Consider the following statements :

Statement-I : Giant stars live much longer than dwarf stars.

Statement-II : Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.

Which one of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

(c) Statement-I is correct, but Statement-II is incorrect

(d) Statement-I is incorrect, but Statement II is correct

Answer: (d) Statement-I is incorrect, but Statement II is correct

Notes:

• Giant stars do not live much longer than dwarf stars. In fact, giant stars have shorter lifespans than dwarf stars. Giant stars, due to their larger mass and higher core temperatures, burn through their nuclear fuel much more rapidly, leading to shorter lifespans.
  • Dwarf stars, especially red dwarfs, can have lifespans of tens to hundreds of billions of years, while giant stars typically live for millions to a few billion years.
• Giant stars have a much higher rate of nuclear reactions compared to dwarf stars. This is because they have larger masses and hotter, denser cores, which accelerate the fusion processes.

Feature	Giant Stars	Dwarf Stars
Mass	8-100 times the mass of the Sun	Less than 5 times the mass of the Sun
Size	Much larger than the Sun (up to 1,000 times wider)	Smaller than the Sun
Lifespan	Shorter, millions to a few billion years	Longer, tens to hundreds of billions of years
Luminosity	Much brighter than the Sun	Dimmer than the Sun
Core Temperature	Higher than dwarf stars	Lower than giant stars
Nuclear Reactions	Higher rate of nuclear reactions	Lower rate of nuclear reactions
Evolutionary Path	Can become red giants or supergiants before ending as neutron stars or black holes	Typically become white dwarfs or red dwarfs after the main sequence

Q. Which one of the following is synthesised in human body that dilate blood vessels and increases blood flow?

(a) Nitric oxide

(b) Nitrous oxide

(c) Nitrogen dioxide

(d) Nitrogen Pentoxide

Answer: (a) Nitric oxide

Notes:

• Nitric Oxide (NO): Nitric oxide is a molecule synthesized in the human body that plays a crucial role in various physiological processes, including the dilation of blood vessels (vasodilation) and increasing blood flow.
  • It is produced by endothelial cells lining the blood vessels and works by relaxing the smooth muscles in the vessel walls, leading to dilation and improved blood circulation.

• Nitrous Oxide (N2O): Nitrous oxide, also known as laughing gas, is an anesthetic and analgesic used in medical settings.
  • It’s a colorless, non-flammable gas with a slightly sweet scent and taste.
  • In addition to its recreational use, nitrous oxide is also used in various medical and industrial applications, including as an anesthetic and an engine performance enhancer.
• Nitrogen Dioxide (NO2): Nitrogen dioxide (NO2) is a reddish-brown, toxic gas that is a major air pollutant.
  • It’s primarily produced by burning fuels like coal, oil, and gas.
  • NO2 contributes to the formation of ozone and other harmful pollutants, negatively impacting human health and the environment.
• Nitrogen Pentoxide (N2O5): Dinitrogen pentoxide, also known as nitrogen pentoxide or nitric anhydride, is a chemical compound with the formula N2O5. It’s a colorless solid that sublimes slightly above room temperature and is a potent oxidizer.
  • The uses of dinitrogen pentoxide are-
    • It is used as a robust oxidizer in high-fuel rockets.
    • It is used to ease nitration in non-water based solvents.
    • It is used for making explosives.
    • It is used to denote the light intensities transmitted when the cell was occupied by the decomposing nitrogen pentoxide and when occupied by the completely decomposed nitrogen pentoxide.

Q. Consider the following Activities:

1. Identification of narcotics on passengers at airports or in aircraft
2. Monitoring of Precipitation
3. Tracking the migration of animals

In how many of the above activities can the radars be used?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (b) Only two

Notes:

• Radars use radio waves to detect and locate objects by transmitting pulses and analyzing the reflected signals. They measure distance, speed, and direction, playing a vital role in aviation, maritime navigation, weather forecasting, and military applications. Radars enable precise tracking and surveillance over long distances and in various conditions.
• Radars are generally not used for the identification of narcotics. Instead, techniques such as X-ray scanners, chemical detection, and sniffer dogs are used for this purpose.
• Radars are widely used in weather forecasting to monitor precipitation. Weather radars, such as Doppler radar, can detect rain, snow, hail, and other forms of precipitation by measuring the return of radio waves that bounce off raindrops or snowflakes.
• Radars can be used to track the migration of animals, particularly birds. Radar technology can detect the movement of birds and other flying animals, providing valuable data for studying migration patterns and behavior.

Q. In which of the following are hydrogels used?

1. Controlled drug delivery in patients
2. Mobile air-conditioning systems
3. Preparation of industrial lubricants

Select the correct answer using the code given below:

(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3

Answer: (d) 1, 2 and 3

Hydrogels

• Hydrogels are three-dimensional, cross-linked polymer networks that can absorb and retain large amounts of water, forming a gel-like substance.
• These materials, composed of hydrophilic polymers, can expand in aqueous solutions and maintain their structure due to chemical or physical cross-linking. They exhibit high elasticity and can swell or collapse depending on their hydration level.
• Types of Hydrogels:
  • Hydrogels can be classified based on their composition (natural or synthetic), cross-linking mechanism (chemical or physical), and their ability to respond to external stimuli. Some examples include:
    • Natural hydrogels: Derived from natural polymers like collagen, hyaluronic acid, or starch.
    • Synthetic hydrogels: Made from synthetic polymers like polyacrylamide or polyvinyl alcohol.
    • Smart hydrogels: Responsive to external stimuli like pH, temperature, or light.
• Applications:
  • Hydrogels have a wide range of applications due to their unique properties, including:
    • Biomedical:
      • Drug delivery: They can be used to deliver drugs in a controlled manner.
      • Tissue engineering: Hydrogels can provide a three-dimensional environment for cell growth and tissue regeneration.
      • Wound dressing: They can help keep wounds moist and promote healing.
    • Hygiene products: Hydrogels are used in diapers and other absorbent products.
    • Agriculture: They can be used to improve soil water retention.
    • Cosmetics: Some hydrogels are used in cosmetics for moisturizing and other purposes.
    • Food industry: They can be used as food additives or for creating specific textures.
  • Hydrogels have applications in mobile air-conditioning systems due to their ability to absorb and release water. They can be used in evaporative cooling systems, where the hydrogel helps in maintaining humidity and cooling effects.
  • Hydrogels are also used in the preparation of industrial lubricants. They help in reducing friction and wear between mechanical parts by forming a lubricating layer that can retain moisture and provide smooth movement.

Q. Which one of the following is the exhaust Pipe emission from Fuel Cell Electric Vehicles powered by hydrogen?

(a) Hydrogen peroxide

(b) Hydronium

(c) Oxygen

(d) Water vapour

Answer: (d) Water vapour

Fuel Cell Electric Vehicle (FCEV)

• Fuel Cell Electric Vehicle (FCEV) is a type of electric vehicle that uses a fuel cell to generate electricity from hydrogen, instead of relying on a battery. This electricity then powers an electric motor, driving the vehicle.
  • FCEVs produce only water vapor as a byproduct, making them a zero-emissions alternative to traditional internal combustion engine vehicles.
• Mechanism: The Fuel Cell Electric Vehicle (FCEV) combines hydrogen and oxygen to generate an electric current and water is the only byproduct.
  • Hydrogen + Oxygen = Electricity + Water Vapour
    • 2H₂ (g) + O₂ (g) → 2 H₂O (l)
• Fuel Cell Electric Vehicle (FCEV) engines are similar to the conventional internal combustion engines because they also rely on a constant supply of fuel (hydrogen) and oxygen.
  • However, there are no moving parts in the fuel cell, so they are more efficient and reliable.
• Stationary fuel cells are the largest and most powerful fuel cells. These are being designed to provide a cleaner, reliable source of on-site power to hospitals, banks, airports and homes.
• The successful development of the technology would provide energy for transportation and electric power.
• Hydrogen fuel tanks are made from highly durable carbon fibre. Some FCEVs have a triple-layer hydrogen tank made of woven carbon fibre.

Advantages:

• FCEVs produce much smaller quantities of greenhouse gases and none of the air pollutants that cause health problems.
• Fuel cells emit only heat and water as a byproduct and are far more energy-efficient than traditional combustion technologies.
• FCEVs do not need to be plugged in for charging, like battery-powered EVs.
• There is a wide availability of resources for producing hydrogen.

Disadvantages:

• The process of making hydrogen needs energy, often from fossil fuel sources, which raises questions over hydrogen’s green credentials.
• Handling of hydrogen is a safety concern because it is more explosive than petrol.
• These vehicles are expensive and fuel dispensing pumps are scarce.

Q. Recently, the term “pumped-storage hydropower” is actually and appropriately discussed in the context of which one of the following?

(a) Irrigation of terraced crop fields

(b) Lift irrigation of cereal crops

(c) Long-duration energy storage

(d) Rainwater harvesting system

Answer: (c) Long-duration energy storage

Pumped storage hydropower (PSH):

• Pumped storage hydropower (PSH) is a method of storing energy by using excess electricity to pump water from a lower reservoir to a higher one. When electricity demand is high, the water is released back down, passing through turbines to generate power.
  • It essentially functions as a “battery” for the power grid, storing energy and releasing it as needed.
• PSH is a fundamentally simple system that consists of two water reservoirsat different elevations.
• Working:
  • When there is excess electricity available, such as during off-peak hours or from renewable sources like solar and wind, it is used to pump water from the lower reservoir to the upper reservoir.
  • When there is a demand for electricity, the water is released from the upper reservoir back down to the lower reservoir, passing through turbines that generate electricity.
  • The system also requires power as it pumps water back into the upper reservoir (recharge). 
• PSH plants operate much like conventional hydropower plants, except PSH has the ability to use the same water over and over again. 
• The technology absorbs surplus energy at times of low demand and releases it when demand is high.
• The energy storage capacity of a PSH depends on the size of its two reservoirs, while the amount of power generated is linked to the size of the turbine.
• There are two main types of PSH:

Q. “Membrane Bioreactors” are often discussed in the context of:

(a) Assisted reproductive technologies

(b) Drug delivery nanotechnologies

(c) Vaccine production technologies

(d) Wastewater treatment technologies

Answer: (d) Wastewater treatment technologies

Membrane Bioreactors:

• The membrane bioreactor is a highly efficient, low-cost, and environmentally friendly device for the in situ treatment of wastewater.
• Membrane Bioreactor (MBR) combines biological treatment with membrane filtration to remove both organic matter and suspended solids from wastewater.
• It uses membranes to filter the treated wastewater, separating it from the microorganisms. This allows for higher solids concentrations in the bioreactor, reducing the size of the treatment tanks.

Q. Consider the following aircraft:

1. Rafael
2. MiG-29
3. Tejas MK-1

How many of the above are considered fifth generation fighter aircraft?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (d) None

Notes:

• Rafael (Rafale): The Rafale is a French twin-engine, multirole fighter aircraft developed by Dassault Aviation.
  • It is considered a 4.5 generation fighter aircraft, incorporating advanced avionics and stealth features but not meeting all the criteria for a fifth-generation fighter.

• MiG-29: The MiG-29 is a fourth-generation jet fighter aircraft designed in the Soviet Union and is used by various countries. India is the second-largest operator of MiG-29s globally, following Russia.
  • It does not have the advanced stealth, sensor fusion, and avionics of fifth-generation fighters.

• Tejas MK-1: The Tejas MK-1 is an Indian single-engine, multirole light fighter developed by Hindustan Aeronautics Limited (HAL).
  • It is also considered a fourth-generation fighter aircraft.