IAS Prelims GS Questions and Answers - Aug 31, 2016

ANSWER: Mars

Explanation:

• Mars had a warm and wet climate about four billion years ago and provided a more favourable environment for life, say scientists who have discovered fossilised riverbeds on an ancient region of the red planet.
• The study identified over 17,000 km of former river channels on a northern plain called Arabia Terra, providing further evidence of water once flowing on Mars.
• While a few valleys were identified, the team found the existence of many systems of fossilised riverbeds which are visible as inverted channels spread across the Arabia Terra plain.

ANSWER: Neither 1 nor 2

Explanation:

• Since the 1970s, scientists have identified valleys and channels on Mars which they think were carved out and eroded by rain and surface runoff, just like on Earth.
• Similar structures had not been seen on Arabia Terra until the team analysed high resolution imagery from NASA's Mars Reconnaissance Orbiter (MRO) spacecraft.
• While a few valleys were identified, the team found the existence of many systems of fossilised riverbeds which are visible as inverted channels spread across the Arabia Terra plain.
• The inverted channels are similar to those found elsewhere on Mars and Earth. They are made of sand and gravel deposited by a river and when the river becomes dry, the channels are left upstanding as the surrounding material erodes.
• On Earth, inverted channels often occur in dry, desert environments like Oman, Egypt, or Utah, where erosion rates are low - in most other environments, the channels are worn away before they can become inverted.

ANSWER: Startup Data Xgen Technologies

Explanation:

• Startup Data Xgen Technologies has started a paid email address service in Hindi characters or Devanagari script, and plans to roll out free registration of such IDs on the lines of Gmail, Outlook and Yahoo soon.
• A few hundred IDs have been created till now on .bharat domain, which is available in Devanagari script. Anyone interested in Hindi script ID can visit website and buy email package as per their need.
• Email sent from these addresses is supported by leading service providers like Gmail and Microsoft.
• Besides communicating in Hindi, people can send emails from addresses created in Hindi script to Gmail, Outlook and some of the other addresses. The company wishes to start a free email id on .bharat domain soon just like Gmail of India for Hindi domains and soon we will work with government to do that.
• To bring more people on Internet, government is pushing website and email addresses in Hindi or Devanagari scripts.
• The National Internet Exchange of India (NIXI) has asked domain or website name sellers to provide free .bharat (in Devanagari script) to everyone who buys a ".in" domain name.

ANSWER: Neither 1 nor 2

Explanation:

• Globally, many airlines are already offering Wi-Fi for passengers, but they currently have to switch off the facility when they enter the Indian airspace.
• Carriers will have the option to charge for the service though some of them can offer free usage up to a certain limit or in some specific flying classes.
• Availability of Wi-Fi is also expected to provide local airlines with an additional source of revenues amid stiff competition in the Indian aviation market, which has been witnessing one of the highest passenger traffic growth rates in the world.
• The facility will be available for domestic as well as foreign carriers flying in Indian skies, for which the technical and operational modalities are in the advanced stage of finalisation.
• Generally, Wi-Fi facility for fliers can be provided either through air-to-ground technology or satellite connectivity and the latter will be expensive.

ANSWER: Milk-Protein

Explanation:

• US scientists are developing an environment-friendly edible packaging film made of milk proteins that may help prevent food spoilage and reduce plastic waste.
• Made out of milk protein, the wrapping material could be on the shelves within three years.
• Most foods such as meats, breads, cheeses and snacks come wrapped in plastic packaging.
• Not only does this create a lot of non-recyclable, non-biodegradable waste, but thin plastic films are not good at preventing spoilage. Some plastics are also suspected of leaching potentially harmful compounds into food.

ANSWER: Only 1

Explanation:

• When used in packaging, they could prevent food waste during distribution along the food chain.
• It also does not degrade, creating tonnes of plastic waste that sits in landfills for years. To create an all-around better packaging solution, researchers are developing an environmentally friendly film made of the milk protein casein.
• These casein-based films are up to 500 times better than plastics at keeping oxygen away from food and, because they are derived from milk, are biodegradable, sustainable and edible.
• Some commercially available edible packaging varieties are already available, but these are made of starch, which is more porous and allows oxygen to seep through its microholes.
• The milk-based packaging, however, has smaller pores and can thus create a tighter network that keeps oxygen out.
• In addition to being used as plastic pouches and wraps, this casein coating could be sprayed onto food, such as cereal flakes or bars.

ANSWER: Supersonic combustion ramjets

Explanation:

• Scramjet programs refer to research and testing programs for the development of supersonic combustion ramjets, known as scramjets.
• The collection and use of atmospheric air involves challenges as the launch vehicle speeds through atmosphere at supersonic speeds. This calls for the development of ramjet or scramjet (supersonic combustion ramjet) technologies.

ANSWER: 1, 3

Explanation:

• India is the fourth country to demonstrate the flight testing of Scramjet Engine after the United States, Russia and European Space Agency.
• The Scramjet engine will also be used eventually to power ISRO’s reusable launch vehicle at hypersonic speed.
• The Scramjet engine designed by ISRO uses Hydrogen as fuel and the Oxygen from the atmospheric air as the oxidiser.
• The test was the maiden short duration experimental test of ISRO’s Scramjet engine with a hypersonic flight at Mach 6.

ANSWER: Only 2

Explanation:

• A scramjet (supersonic combusting ramjet) is a variant of a ramjet air breathing jet engine in which combustion takes place in supersonic airflow.
• As in ramjets, a scramjet relies on high vehicle speed to forcefully compress the incoming air before combustion (hence ramjet), but a ramjet decelerates the air to subsonic velocities before combustion, while airflow in a scramjet is supersonic throughout the entire engine.
• This allows the scramjet to operate efficiently at extremely high speeds.
• In a ramjet, the combustion chamber - where the air is mixed with fuel and ignited - only works at subsonic speeds. So the intake slows the air down, releasing some of its energy as a shock wave, but this reduces fuel efficiency.

ANSWER: Neither 1 nor 2

Explanation:

• A dual mode ramjet (DMRJ) is a type of jet engine where a ramjet transforms into scramjet over Mach 4-8 range, which means it can efficiently operate both in subsonic and supersonic combustor modes.
• The Dual Mode Ramjet (DMRJ), the ramjet-scramjet combination, is currently under development, which will operate during the crucial Mach 3 to Mach 9 ascend flight of the launch vehicle.
• An Advanced Technology Vehicle (ATV) based on sounding rocket was developed for DMRJ Flight Technology demonstration and one developmental flight, ATV-D01, was conducted.

ANSWER: 1, 2

Explanation:

• With this flight, critical technologies such as ignition of air breathing engines at supersonic speed, holding the flame at supersonic speed, air intake mechanism and fuel injection systems have been successfully demonstrated.
• Some of the technological challenges handled by ISRO during the development of Scramjet engine include the design and development of Hypersonic engine air intake, the supersonic combustor, development of materials withstanding very high temperatures, computational tools to simulate hypersonic flow, ensuring performance and operability of the engine across a wide range of flight speeds, proper thermal management and ground testing of the engines.

ANSWER: Mach 3-6

Explanation:

• Ramjets work most efficiently at supersonic speeds around Mach 3 (three times the speed of sound) and can operate up to speeds of Mach 6. However, the ramjet efficiency starts to drop when the vehicle reaches hypersonic speeds (above Mach 5).
• A scramjet engine is an improvement over the ramjet engine as it efficiently operates at hypersonic speeds and allows supersonic combustion. Thus it is known as Supersonic Combustion Ramjet, or Scramjet.
• A dual mode ramjet (DMRJ) is a type of jet engine where a ramjet transforms into scramjet over Mach 4-8 range, which means it can efficiently operate both in subsonic and supersonic combustor modes.