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
May 27,2020

Due to impacts of COVID-19, shipments of total mobile phones are forecast to decline 14.6% in 2020, while smartphone shipments will achieve a slightly slower decline of 13.7 % year over year to total 1.3 billion units this year, according to a Gartner forecast on Tuesday.

"While users have increased the use of their mobile phones to communicate with colleagues, work partners, friends and families during lockdowns, reduced disposable income will result in fewer consumers upgrading their phones," Ranjit Atwal, Senior Research Director at Gartner, said in a statement.

"As a result, phone lifetimes will extend from 2.5 years in 2018 to 2.7 years in 2020," said Atwal.

In 2020, affordable 5G phones were expected to be the catalyst to increase phone replacements, but now it is unlikely to be the case.

5G phones are now forecast to represent only 11% of total mobile phone shipments in 2020.

"The delayed delivery of some 5G flagship phones is an ongoing issue," said Annette Zimmermann, Research Vice President at Gartner.

"Moreover, the lack of 5G geographical coverage along with the increasing cost of the 5G phone contract will impact the choice of a 5G phone."

Overall, spending on 5G phones will be impacted in most regions apart from China, where continued investment in 5G infrastructure is expected, allowing providers in China to effectively market 5G phones.

The combined global shipments PCs, tablets and mobile phones are on pace to decline 13.6% in 2020, according to the forecast.

PC shipments are expected to decline 10.5% this year. Shipments of notebooks, tablets and Chromebooks are forecast to decline slower than the PC market overall in 2020.

"The forecasted decline in the PC market in particular could have been much worse," said Atwal.

"However, government lockdowns due to COVID-19 forced businesses and schools to enable millions of people to work from home and increase spending on new notebooks, Chromebooks and tablets for those workers. Education and government establishments also increased spending on those devices to facilitate e-learning."

Gartner said that 48 per cent of employees will likely work remotely at least part of the time after the COVID-19 pandemic, compared to 30 % pre-pandemic.

Overall, the work from home trend will make IT departments shift to more notebooks, tablets and Chrome devices for work.

"This trend combined with businesses required to create flexible business continuity plans will make business notebooks displace desk based PCs through 2021 and 2022," said Atwal.

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Agencies
June 18,2020

New Delhi, Jun 18: Vodafone Idea on Thursday told the Supreme Court that it has incurred Rs 1 lakh crore losses as it insisted it is not in a position to furnish bank guarantees.

A bench comprising Justices Arun Mishra, S. Abdul Nazeer, and M.R. Shah, taking up the adjusted gross revenue (AGR) matter through video conferencing, directed the telecom companies to submit their financial documents and books for the last 10 years.

Asking Vodafone if it was a foreign company, the bench said that how can the company say it would not furnish any bank guarantee.

"What if you fly away overnight in future without paying anything?" it asked.

Senior advocate Mukul Rohatgi, representing Vodafone Idea, denied his client is a completely foreign firm and cited before the bench its tie-ups and investments.

Vodafone owes over Rs 58,000 crore as AGR dues and so far, has paid close to Rs 7,000 crore.

Rohatgi contended before the court that the telecom company is in a tough situation, and cannot furnish any fresh bank guarantee, as profits have eluded the company in past many quarters. He submitted before the bench that Rs 15,000 crore bank guarantees are lying with the government, and his client's losses are over Rs 1 lakh crore.

"I cannot offer any more surety," he informed the bench.

Justice Mishra noted that this is public money and these dues should be recovered. "Do not tell us that you will pay if you were to make profits... the money must come," he noted.

Justice Shah observed that the telecom industry is the only industry which earned during the Covid-19 pandemic. "After all, this money will be used for public welfare", he said.

Rohatgi argued that his client would have to fold up if orders were issued to clear dues tomorrow. "11,000 employees will have to go without notice, as we cannot pay them," he added.

Senior advocate Abhishek Manu Singhvi, appearing for Bharti Airtel, contended before the court that out of Rs 21,000 crore AGR dues, the company has already deposited a sum of Rs 18,000 crore.

He argued that his client has given a bank guarantee, in excess of demand, to DoT, and supported the proposal for phased repayment of remaining AGR dues. He insisted that the company needs to sit down with the government and calculate the dues. Airtel owes Rs 25,976 crore after paying Rs 18,000 crore, as per the government.

Senior advocate Arvind Datar, representing Tata Telecom, informed the bench that his client has paid Rs 6,504 crore in AGR dues so far, and furnishing a bank guarantee may adversely impact investments in the sector.

The total AGR dues are close to Rs 1.5 lakh crore.

The top court will now take up the matter in the third week of July.

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Agencies
February 26,2020

Unnao, Feb 26: Ever heard of someone wishing a 'bright future' for the dead? In a bizarre incident in Uttar Pradesh's Unnao district, a village head issued a death certificate with the wish for an elderly man who had died last month.

The incident took place in the Sirwariya village in Asoha block where an elderly person Laxmi Shankar died after a prolonged illness on January 22.

His son went to the village head Babulal and requested him to issue a death certificate that he needed for some financial transactions.

Babulal not only issued the death certificate, but also 'wished' 'a bright future for the deceased' on the document.

The village head wrote in the death certificate -- "Main inke ujjwal bhavishya ki kaamna karta hoon (I wish him a bright future)."

The letter went viral on the social media on Monday after which the village head apologised for the error and issued a new death certificate.

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