World's most heat resistant material found

December 25, 2016

London, Dec 25: Scientists have identified materials that can withstand temperatures of nearly 4,000 degrees Celsius, an advance that may pave the way for improved heat resistant shielding for the faster-than-ever hypersonic space vehicles.heat

Researchers from Imperial College London in the UK discovered that the melting point of hafnium carbide is the highest ever recorded for a material.

Tantalum carbide (TaC) and hafnium carbide (HfC) are refractory ceramics, meaning they are extraordinarily resistant to heat. Their ability to withstand extremely harsh environments means that refractory ceramics could be used in thermal protection systems on high-speed vehicles and as fuel cladding in the super-heated environments of nuclear reactors.

However, there has not been the technology available to test the melting point of TaC and HfC in the lab to determine how truly extreme an environment they could function in. The researchers developed a new extreme heating technique using lasers to test the heat tolerance of TaC and HfC.

They used the laser-heating techniques to find the point at which TaC and HfC melted, both separately and as mixed compositions of both.

They found that the mixed compound (Ta0.8Hf0.20C) was consistent with previous research, melting at 3,905 degrees Celsius, but the two compounds on their own exceeded previous recorded melting points. The compound TaC melted at 3,768 degrees Celsius, and HfC melted at 3,958 degrees Celsius.

The findings may pave the way for the next generation of hypersonic vehicles, meaning spacecraft could become faster than ever.

"The friction involved when travelling above Mach 5 -hypersonic speeds - creates very high temperatures," said Omar Cedillos-Barraza, currently an Associate Professor at the University of Texas.

"So far, TaC and HfC have not been potential candidates for hypersonic aircraft, but our new findings show that they can withstand even more heat than we previously thought - more than any other compound known to man," said Cedillos-Barraza, who carried out the research as a PhD student at Imperial College London

"This means that they could be useful materials for new types of spacecraft that can fly through the atmosphere like a plane, before reaching hypersonic speeds to shoot out into space," he said.

"These materials may enable spacecraft to withstand the extreme heat generated from leaving and re-entering the atmosphere," he added.

Examples of potential uses for TaC and HfC could be in nose caps for spacecraft, and as the edges of external instruments that have to withstand the most friction during flight.

Currently, vehicles going over Mach 5 speeds do not carry people, but Cedillos-Barraza suggests it may be possible in
the future.

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Agencies
February 5,2020

San Francisco, Feb 5: After a German artist, Simon Weckert, demonstrated how he "hacked" Google Maps with 99 smartphones and a wagon to create "virtual traffic jams" on the streets of Berlin, Google responded to the incident saying it "appreciates" creative use of maps.

Admitting that it has not quite cracked travelling by wagon, the tech giant also hinted that it might use cases like this to improve how its maps work.

"We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time," 9to5Google quoted a Google spokesperson as saying.

In a YouTube video, Weckert showed that he put 99 smartphones with Google Maps onto a small wagon cart and then wheeled that cart around various streets in Berlin, including outside the Google office, Android Authority reported on Monday.

The smartphones "apparently fooled Google Maps" into thinking that there was a high concentration of users on those streets.

Because the second-hand phones were in a cart, Maps was further tricked into believing that the traffic was slow-moving.

As a result, the navigation app started showing virtual traffic jams by turning green streets to red in the online navigational tool, showcasing how digital technology can have a real impact on the real world.

"Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymised data from people who have location services turned on and contributions from the Google Maps community," the Google spokesperson said.

"We've launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven't quite cracked travelling by wagon," the statement added. After a German artist, Simon Weckert, demonstrated how he "hacked" Google Maps with 99 smartphones and a wagon to create "virtual traffic jams" on the streets of Berlin, Google responded to the incident saying it "appreciates" creative use of maps.

Admitting that it has not quite cracked travelling by wagon, the tech giant also hinted that it might use cases like this to improve how its maps work.

"We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time," 9to5Google quoted a Google spokesperson as saying.

In a YouTube video, Weckert showed that he put 99 smartphones with Google Maps onto a small wagon cart and then wheeled that cart around various streets in Berlin, including outside the Google office, Android Authority reported on Monday.

The smartphones "apparently fooled Google Maps" into thinking that there was a high concentration of users on those streets.

Because the second-hand phones were in a cart, Maps was further tricked into believing that the traffic was slow-moving.

As a result, the navigation app started showing virtual traffic jams by turning green streets to red in the online navigational tool, showcasing how digital technology can have a real impact on the real world.

"Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymised data from people who have location services turned on and contributions from the Google Maps community," the Google spokesperson said.

"We've launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven't quite cracked travelling by wagon," the statement added.

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Agencies
June 29,2020

New Delhi, Jun 29: Witnessing azure skies and breathable air for the last three months, Delhi on Monday recorded deterioration in its air quality, with particulate matter with diameter of 2.5 and 10 microns -- too small to be filtered out of the human body -- standing at 52 and 297 micrograms per cubic respectively.

Gufran Beig, Project Director of System of Air Quality Weather Forecasting and Research (SAFAR), said that the sudden spike in air pollution is due to a mild dust storm blowing from Rajasthan.

"Since the wind direction is changing and moist air is coming in, the air quality in Delhi will become better by tomorrow," Beig told IANS.

Central Pollution Control Board (CPCB) data showed that the overall air quality near Delhi Technical University (DTU) area stood at 326 micrograms per cubic, followed by 308 at Narela and 307 at Mundka.

Out of 36 stations, the AQI in as many as 30 stations was above 200 micrograms per cubic till 1 pm on Monday.

The System of Air Quality Weather Forecasting and Research categorises air quality in the 0-50 range as good, 51-100 as satisfactory, 101-200 as moderate, 201-300 as poor, 301-400 as very poor, and above 400 as severe.

According to SAFAR's website, "PM 10 (coarser dust particle) is the lead pollutant. AQI is likely to improve to moderate category by tomorrow, and further improvement is expected by July 1."

Researchers indicated that PM 10 and PM 2.5 will be 170 and 47 micrograms per cubic on Tuesday.

With no vehicles plying on the roads or industries shut due to the lockdown since March 25, Delhi's air quality had improved drastically.

According to a study conducted by the Indian Institute of Technology (IIT), Delhi, if the low levels of air pollution reached during the lockdown period are maintained, India's annual death toll could reduce by 6.5 lakh.

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Agencies
July 4,2020

The Mars Colour Camera (MCC) onboard ISRO's Mars Orbiter Mission has captured the image of Phobos, the closest and biggest moon of Mars.

The image was taken on July 1 when MOM was about 7,200 km from Mars and 4,200 km from Phobos.

"Spatial resolution of the image is 210 m.

This is a composite image generated from 6 MCC frames and has been color corrected," ISRO said in an update along with the image.

Phobos is largely believed to be made up of carbonaceous chondrites.

According to ISRO, "the violent phase that Phobos has encountered is seen in the large section gouged out from a past collision (Stickney crater) and bouncing ejecta."

"Stickney, the largest crater on Phobos along with the other craters (Shklovsky, Roche & Grildrig) are also seen in this image," it said.

The mission also known as Mangalyaan was initially meant to last six months, but subsequently ISRO had said it had enough fuel for it to last "many years."

The country had on September 24, 2014 successfully placed the Mars Orbiter Mission spacecraft in orbit around the red planet, in its very first attempt, thus breaking into an elite club.

ISRO had launched the spacecraft on its nine-month- long odyssey on a homegrown PSLV rocket from Sriharikota in Andhra Pradesh on November 5, 2013.

It had escaped the earth's gravitational field on December 1, 2013.

The Rs 450-crore MOM mission aims at studying the Martian surface and mineral composition as well as scan its atmosphere for methane (an indicator of life on Mars).

The Mars Orbiter has five scientific instruments - Lyman Alpha Photometer (LAP), Methane Sensor for Mars (MSM), Mars Exospheric Neutral Composition Analyser (MENCA), Mars Colour Camera (MCC) and Thermal Infrared Imaging Spectrometer

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