'New light-absorbent material to cool buildings, cars'

February 5, 2017

Los Angeles, Feb 5: Scientists have developed a thin, flexible, lightweight material that can block thermal detection and absorb light from every angle to keep buildings and cars cool on hot summer days.

absorbentThe material, developed by engineers at the University of California San Diego in the US, is called a near-perfect broadband absorber.

It absorbs more than 87 per cent of near-infrared light (1,200 to 2,200 nanometre wavelengths), with 98 per cent absorption at 1,550 nanometres, the wavelength for fiber optic communication.

The material is capable of absorbing light from every angle. It also can theoretically be customised to absorb certain wavelengths of light while letting others pass through.

Materials that "perfectly" absorb light already exist, but they are bulky and can break when bent. They also cannot be controlled to absorb only a selected range of wavelengths, which is a disadvantage for certain applications.

Imagine if a window coating used for cooling not only blocked infrared radiation, but also normal light and radio waves that transmit television and radio programmes.

By developing a novel nanoparticle-based design, a team led by professors Zhaowei Liu and Donald Sirbuly at the UC San Diego has created a broadband absorber that is thin, flexible and tunable.

"This material offers broadband, yet selective absorption that could be tuned to distinct parts of the electromagnetic spectrum," said Liu.

The absorber relies on optical phenomena known as surface plasmon resonances, which are collective movements of free electrons that occur on the surface of metal nanoparticles upon interaction with certain wavelengths of light.

Metal nanoparticles can carry a lot of free electrons, so they exhibit strong surface plasmon resonance - but mainly in visible light, not in the infrared.

The researchers reasoned that if they could change the number of free electron carriers, they could tune the material's surface plasmon resonance to different wavelengths of light.

"Make this number lower, and we can push the plasmon resonance to the infrared. Make the number higher, with more electrons, and we can push the plasmon resonance to the ultraviolet region," said Sirbuly.

The problem with this approach is that it is difficult to do in metals. To address this challenge, engineers designed and built an absorber from materials that could be modified, or doped, to carry a different amount of free electrons: semiconductors.

Researchers used a semiconductor called zinc oxide, which has a moderate number of free electrons, and combined it with its metallic version, aluminium-doped zinc oxide, which houses a high number of free electrons — not as much as an actual metal, but enough to give it plasmonic properties in the infrared.

The study was published in the journal Proceedings of the National Academy of Sciences.

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News Network
February 5,2020

Feb 5: Tesla is making Elon Musk a lot richer without paying him a dime.

A blistering stock rally has bolstered the value of CEO Musk's 19% stake in the electric car maker by $16 billion since the start of 2020, to $30 billion.

Tuesday's steep climb in the share price could sweeten Musk's payday under his record-breaking compensation package, which is built on stock options that rely on market value targets. Two milestones have now been achieved that could see Musk unlock options worth $1.8 billion.

The controversial chief executive, who is also the majority owner and CEO of rocket maker SpaceX, recently testified that he did not have a lot of cash as he successfully defended himself in a defamation lawsuit. He previously has taken loans using his Tesla shares as collateral.

Musk does not take a salary, choosing instead a risky options package that envisions the stock market value of Tesla rising to $650 billion over 10 years, a prospect that was derided by some investors when the deal was announced in 2018.

That target now looks less crazy. Shares of Tesla have rallied over 50% since the company posted its second consecutive quarterly profit last Wednesday, which was viewed as a major accomplishment for a company competing against established automotive heavyweights including General Motors Co  and BMW.

Tesla shares have climbed about 400% since early June, helped by the company's better-than-expected financial results and ramped-up production at its new car factory in Shanghai.

On Tuesday, Tesla surged as much as 24% before falling back in the final minutes of the trading session to end the day up 13.7%. That put its market capitalization at $160 billion, almost twice the combined value of Ford Motor and General Motors.

The shares had also rallied on Monday, partly fueled by Panasonic Corp's 6752.T saying its automotive battery venture with Tesla was profitable for the first time.

The options Musk was awarded in 2018 vest incrementally based on targets for Tesla's stock market value and its financial performance. The market capitalization would have to sustainably rise by $50 billion increments over the agreement's 10-year period, with the full package payout reached if the market cap reaches $650 billion, as well as the company's meeting revenue and profit targets.

Musk is on his way to seeing his first two tranches of options vest. He achieved operational targets on revenue and adjusted earnings last year.

The rise in Tesla's market capitalization last month to a target of $100 billion opened the way for Musk's first tranche of options to vest. With Tuesday's surging share price, the market capitalization blew past the second target of $150 billion, opening the way for the second tranche to vest. Tesla's market capitalization must stay at or above each target level for one- and six-month averages for each set of options to vest.

Tesla was valued at about $52 billion when shareholders approved the pay package in March 2018, a time when the company faced a cash crunch, production delays and increasing competition from rivals.

A full payoff for Musk would surpass anything previously granted to U.S. executives, according to Institutional Shareholder Services, a proxy advisor that recommended investors reject the pay package deal at the time.

Musk currently owns about 34 million Tesla shares, and his compensation package would let him buy another 20.3 million shares if all his options tranches vest.

When Tesla unveiled Musk’s package, it said he could in theory reap as much as $55.8 billion if no new shares were issued. However, Tesla has since awarded stock to employees and last year sold $2.7 billion in shares and convertible bonds, diluting the value of the stock.

Musk has transformed Tesla from a niche car maker with production problems into the global leader in electric vehicles, with U.S. and Chinese factories. So far it has stayed ahead of more established rivals including BMW and Volkswagen.

Many investors remain skeptical that Tesla can consistently deliver profit, cash flow and growth. More Wall Street analysts rate Tesla "sell" than "buy," and the company's stock is the most shorted on Wall Street.

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Agencies
March 7,2020

New Delhi, Mar 7: The Union government has issued a Global Invite for Expression of Interest for disinvestment in Bharat Petroleum Corporation Limited (BPCL) from prospective bidders with a minimum net worth of $10 billion as of Saturday.

The EoI submissions can be made till May 2, whereas investor queries will be entertained till April 4.

Another condition pertains to a maximum of four members are permitted in a consortium, and the lead member must hold 40 per cent in proportion. Other members of the consortium must have a minimum $1 billion net worth.

The EOI allows changes in the consortium within 45 days, though the lead member cannot be changed.

The GoI proposes to disinvest its entire shareholding in BPCL comprising 1,14,91,83,592 equity shares held through the Ministry of Petroleum and Natural Gas, which constitutes 52.98 per cent of BPCL's equity share capital, along with the transfer of management control to the strategic buyer (except BPCL's equity shareholding of 61.65 per cent in Numaligarh Refinery Limited (NRL) and management control thereon).

The shareholding of BPCL in NRL will be transferred to a Central Public Sector Enterprise operating in the oil and gas sector under the Ministry and accordingly is not a part of the proposed transaction.

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Agencies
June 8,2020

Washington DC, Jun 8: Astronomers acting on a hunch have likely resolved a mystery about young, still-forming stars and regions rich in organic molecules closely surrounding some of them.

They used the National Science Foundation's Karl G Jansky Very Large Array (VLA) to reveal one such region that previously had eluded detection and that revelation answered a longstanding question.

The regions around the young protostars contain complex organic molecules which can further combine into prebiotic molecules that are the first steps on the road to life.

The regions, dubbed "hot corinos" by astronomers, are typically about the size of our solar system and are much warmer than their surroundings, though still quite cold by terrestrial standards.

The first hot corino was discovered in 2003 and only about a dozen have been found so far. Most of these are in binary systems, with two protostars forming simultaneously.

Astronomers have been puzzled by the fact that, in some of these binary systems, they found evidence for a hot corino around one of the protostars but not the other.

"Since the two stars are forming from the same molecular cloud and at the same time, it seemed strange that one would be surrounded by a dense region of complex organic molecules and the other wouldn't," said Cecilia Ceccarelli, of the Institute for Planetary Sciences and Astrophysics at the University of Grenoble (IPAG) in France.

The complex organic molecules were found by detecting specific radio frequencies, called spectral lines, emitted by the molecules. Those characteristic radio frequencies serve as "fingerprints" to identify the chemicals.

The astronomers noted that all the chemicals found in hot corinos had been found by detecting these "fingerprints" at radio frequencies corresponding to wavelengths of only a few millimetres.

"We know that dust blocks those wavelengths, so we decided to look for evidence of these chemicals at longer wavelengths that can easily pass through dust," said Claire Chandler of the National Radio Astronomy Observatory, and principal investigator on the project.

"It struck us that dust might be what was preventing us from detecting the molecules in one of the twin protostars," added Chandler.

The astronomers used the VLA to observe a pair of protostars called IRAS 4A, in a star-forming region about 1,000 light-years from Earth. They observed the pair at wavelengths of centimetres.

At those wavelengths, they sought radio emissions from methanol, CH3OH (wood alcohol, not for drinking). This was a pair in which one protostar clearly had a hot corino and the other did not, as seen using the much shorter wavelengths.

The result confirmed their hunch. "With the VLA, both protostars showed strong evidence of methanol surrounding them. This means that both protostars have hot corinos. The reason we did not see the one at shorter wavelengths was because of dust," said Marta de Simone, a graduate student at IPAG who led the data analysis for this object.

The astronomers cautioned that while both hot corinos now are known to contain methanol, there still may be some chemical differences between them. That, they said, can be settled by looking for other molecules at wavelengths not obscured by dust.

"This result tells us that using centimetre radio wavelengths is necessary to properly study hot corinos," Claudio Codella of Arcetri Astrophysical Observatory in Florence, Italy, said.

"In the future, planned new telescopes such as the next-generation VLA and SKA, will be very important to understanding these objects," added Codella.

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