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Can cryptocurrencies ever be green?

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Can cryptocurrencies ever be green?


green crypto
Credit: Pixabay/CC0 Public Domain

Cryptocurrencies have been condemned over their environmental record at a time when traditional investments have been rapidly moving towards greener environmental, social and governance (ESG) values. So how long will it be until crypto earns its green credentials?

Green investments are assets like bonds that pay for projects with positive environmental and social outcomes. Green bonds for example, contribute to cuts in greenhouse gas emissions, an increase of renewable energy capacity and uptake in clean transport infrastructures.

Crypto investments on the other hand are widely seen as environmentally unfriendly, mainly because of crypto mining and the huge energy it demands. Mining in the context of crypto refers to a mechanism called “proof of work” (POW) where crypto “miners” use specialized computers to solve complex mathematical equations to secure transactions and create new coins. This is where the energy use comes in.

Agencies and organizations like the International Energy Agency and the United Nations have raised concerns about the effects of crypto mining—particularly Bitcoin, the best-known crypto asset.

The environmental footprint of crypto

The United Nations University Institute for Water, Environment and Health estimated that in 2020-2021, Bitcoin networks had significant carbon, water and land footprints. Bitcoin’s carbon footprint was equivalent to burning 38 billion tons of coal, while its water footprint (mainly used for cooling systems) would have met the domestic water needs of more than 300 million people in sub-Saharan Africa.

The Cambridge Blockchain Network Sustainability Index puts the electricity consumption of Bitcoin networks above those of several developed countries, including Norway and Sweden. For investors who are serious about achieving ESG goals, this aspect of crypto would likely be a deal-breaker.

It is also made difficult by the lack of regulations around crypto activities. After years of being on the fringes of financial markets and being considered a “get-rich-quick” venture, crypto investments are becoming mainstream. But there is still little regulation to protect investors and ensure participants adopt practices that are in line with ESG values.

Skeptics point out the major issues plaguing these markets including the use of cryptocurrencies and platforms for money-laundering, scamming, and price manipulation.

So it is certainly hard to make a green case for crypto. But at the same time, it would be misleading to look only at one side of the coin. The fact is that crypto has a challenging but reachable path towards being widely accepted as green.

Decarbonizing the crypto industry

First and foremost, the industry itself has recognized the need to change practices and processes to become more sustainable. In 2021, a significant number of players in the crypto industry signed the crypto climate accord (CCA) with the long-term target of decarbonizing the global crypto industry by 2040.

The CCA set two interim objectives. The first was the development of standards and technologies to have 100% renewably powered blockchains as soon as 2025. The second aim states that signatories should achieve net-zero emissions from electricity consumption by 2030.

Recent developments in technology suggest the industry has started putting plans into action, with the appearance of sustainable tools and infrastructures.

Several companies such as Mara and Argo are working on technologies like energy-efficient immersion cooling systems that significantly reduce the energy consumption required for mining.

These companies are also developing systems that can recycle heat produced by digital assets and from data centers, and redirect it to provide energy to communities. The implementation of these technologies is facilitated by the relative mobility of crypto miners and the opportunities that some governments and regions offer to them.

In addition, the crypto industry has seen the emergence of self-proclaimed environmentally friendly cryptocurrencies, such as Cardano public blockchain and Powerledger. These currencies use a less energy-intensive mechanism called “proof-of-stake” (POS) rather than POW.

Unlike POW, POS miners must stake their holdings (the amount of cryptocurrency) when validating and verifying transactions and records. So if a miner tries to falsify records, they could potentially lose their stake. The process removes the need for the complex computer calculations and so cuts the energy use dramatically. In fact, in 2022, the cryptocurrency Ethereum transitioned from POW to POS, reducing its energy consumption by nearly 100%.

The path towards green crypto is being eased by institutions like the Financial Stability Board, which is taking steps to provide frameworks for understanding, compliance and achievements of ESG goals and values.

Together, these elements could open the door to a future where conscious investors can take a chance on cryptocurrencies.

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Can cryptocurrencies ever be green? (2024, September 25)
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Ingredients used in chewing gum help tilapia survive cold climates

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Ingredients used in chewing gum help tilapia survive cold climates


Ingredients in chewing gum help tilapia survive cold climates
Measured amounts of Arabic gum and lecithin are kneaded into fish food before being dropped into fish tanks containing Nile tilapia fingerlings. Credit: Benha University / National Institute of Oceanography and Fisheries, Egypt

Two common ingredients in ordinary chewing gum—Arabic gum and lecithin—have been found to help improve the overall health of tilapia, helping these fish survive better even in cold climates. This discovery paves the way for raising tilapia for food outside of the tropical regions where they are commonly farmed.

Native to Africa, the Nile tilapia (Oreochromis niloticus) has been raised for food since ancient times due to its fast rate of reproduction. It is now a common sight in markets across tropical countries, including the Philippines and Indonesia. However, O. niloticus is sensitive to cold and only thrives in warm water within the range of 26°C to 30°C.

A recent study by an international team of researchers from Egypt and the Philippines, including Ateneo de Manila University Department of Biology’s Dr. Janice Alano Ragaza, tracked the weight, growth, blood chemistry, and enzyme levels of Nile tilapia fingerlings fed on varying amounts of Arabic gum and lecithin.

Arabic gum and lecithin are common ingredients found in chewing gum and other foodstuffs. Arabic gum is made from sap, usually from the Acacia senegal or Sengalia senegal tree. Lecithin is a common emulsifier derived from a variety of sources, including eggs, soy beans, and sunflower seeds. Both have a wide variety of food uses, including in off-the-shelf chewing gum.

The researchers found that Nile tilapia fingerlings fed on 4 grams of Arabic gum and 10 grams of lecithin per kilogram of fish food over the course of three months led to increased levels of minerals, enzymes, and antioxidants that help the fish overcome the stresses of living in winter.

This change was more than just physiological, as it was found that the diet even activated specific genes associated with surviving cold temperatures.

The study, published in Aquaculture Reports, was jointly undertaken by Benha University, the National Institute of Oceanography and Fisheries in Egypt, and Atene de Manila University in the Philippines.

More information:
Mohamed R. Soaudy et al, The modulatory impact of Arabic gum and lecithin on the efficiency of cold-stressed Nile tilapia (Oreochromis niloticus), Aquaculture Reports (2024). DOI: 10.1016/j.aqrep.2024.102332

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Ingredients used in chewing gum help tilapia survive cold climates (2024, September 25)
retrieved 25 September 2024
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There’s two sides to this semiconductor, and many simultaneous functions

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There’s two sides to this semiconductor, and many simultaneous functions


There's two sides to this semiconductor, and many simultaneous functions
Schematic showing plasma-assisted molecular-beam epitaxial growth of the HEMT-LED. Credit: Nature (2024). DOI: 10.1038/s41586-024-07983-z

Gallium nitride-based semiconductors have been a boon for high-frequency and power electronics. They’ve also revolutionized energy-efficient LED lighting. But no semiconductor wafer has been able to do both at the same time efficiently.

Now Cornell researchers, in collaboration with a team at the Polish Academy of Sciences, have developed the first dual-sided—or “dualtronic”—chip that combines its photonic and electronic functions simultaneously, an innovation that could shrink the size of functional devices, make them more energy efficient and reduce manufacturing costs.

The team’s paper, “Using Both Faces of Polar Semiconductor Wafers for Functional Devices,” published Sept. 25 in Nature. The co-lead authors are doctoral students Len van Deurzen and Eungkyun Kim.

The project was led by Debdeep Jena, the David E. Burr Professor of Engineering in the School of Electrical and Computer Engineering and Department of Materials Science and Engineering, and Huili Grace Xing, the William L. Quackenbush Professor of Electrical and Computer Engineering and of Materials Science and Engineering, both in Cornell Engineering.

Gallium nitride (GaN) is unique among wide-bandgap semiconductors because it has a large electronic polarization along its crystal axis, which gives each of its surfaces dramatically different physical and chemical properties. The gallium, or cation, side has proved useful for photonic devices such as LEDs and lasers, while the nitrogen, or anion, side can host transistors.

The Jena-Xing Laboratory set out to make a functional device in which a high electron mobility transistor (HEMT) on one side drives light-emitting diodes (LEDs) on the other—a feat that hasn’t been achieved in any material.

“To our knowledge, nobody has made active devices on both sides, not even for silicon,” van Deurzen said. “One of the reasons is that there’s no additional functionality you get from using both sides of a silicon wafer because it’s cubic; both sides are basically the same. But gallium nitride is a polar crystal, so one side has different physical and chemical properties than the other, which gives us extra degree in designing devices.”

The project was initially conceived at Cornell by Jena and former postdoctoral researcher Henryk Turski, a co-senior author of the paper, along with Jena and Xing. Turski worked with a team at the Polish Academy of Sciences’ Institute of High Pressure Physics to grow transparent GaN substrates on a single crystal wafer roughly 400 microns thick.

The HEMT and LED heterostructures were then grown in Poland by molecular beam epitaxy. After the epitaxy was completed, the chip was shipped to Cornell, where Kim built and processed the HEMT on the nitrogen polar face.

“The nitrogen polar side is more chemically reactive, which means during device processing the electron channel can be damaged quite easily,” Kim said. “A challenge with nitrogen polar transistor fabrication is to make sure all the plasma processes and the chemical treatment do not damage the transistors. So there was a lot of process development that had to be done for fabricating and designing that transistor.”

Next, van Deurzen built the LED on the metal polar face, using a thick positive photo resist coating to protect the previously processed n-polar face. After each stage, the researchers measured their respective device characteristics and found they had not changed.

“It’s actually a very feasible process,” van Deurzen said. “The devices do not degrade. And this is obviously important if you want to use this as a real technology.”

Since no one has made a double-sided semiconductor device before, the team had to invent a new method to test and measure it. They assembled a “crude” double-side-coated glass plate and wire-bonded one side of the wafer to it, which allowed them to probe both sides from the top.

Because the GaN substrates were transparent for the entire visible range, the light was able to transmit through. The single HEMT device succeeded in driving a large LED, turning it on and off at kilohertz frequencies—plenty for a working LED display.

Currently, LED displays have a separate transistor and independent fabrication processes. An immediate application for the dualtronic chip is microLEDs: fewer components, occupying a smaller footprint and requiring less energy and materials, and manufactured quicker for lower cost.

“A good analogy is the iPhone,” Jena said. “It is, of course, a phone, but it is so many other things. It’s a calculator, it’s a map, it lets you check the internet. So there’s a bit of a convergence aspect of it. I would say our first demonstration of ‘dualtronics’ in this paper is convergence of maybe two or three functionalities, but really it’s bigger than that.

“Now you may not require the different processors to perform different functions, and reduce the energy and speed lost in the interconnections between them that requires further electronics and logic. Many of those functionalities shrink into one wafer with this demonstration.”

Other applications include Complementary Metal-Oxide-Semiconductor (CMOS) devices with a polarization-induced n-channel transistor (which uses electrons) on one side and a p-channel transistor (containing holes) on the other.

In addition, because the GaN substrates have a high piezoelectric coefficient, they can be used as bulk acoustic wave resonators for filtering and amplifying radio frequency signals in 5G and 6G communications. The semiconductors could also incorporate lasers instead of LEDs for “LiFi”—i.e., light-based—transmissions.

“You could essentially extend this to enable the convergence of photonic, electronic and acoustic devices,” van Deurzen said. “You’re essentially limited by your imagination in terms of what you could do, and unexplored functionalities can emerge when we try them in the future.”

More information:
Len van Deurzen, Using both faces of polar semiconductor wafers for functional devices, Nature (2024). DOI: 10.1038/s41586-024-07983-z. www.nature.com/articles/s41586-024-07983-z

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Nuking a huge asteroid could save Earth, lab experiment suggests

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Nuking a huge asteroid could save Earth, lab experiment suggests


A big asteroid could threaten life on Earth -- but nuclear bombs could come to the rescue, a new laboratory experiment suggests
A big asteroid could threaten life on Earth — but nuclear bombs could come to the rescue, a new laboratory experiment suggests.

Humanity could use a nuclear bomb to deflect a massive, life-threatening asteroid hurtling towards Earth in the future, according to scientists who tested the theory in the laboratory by blasting X-rays at a marble-sized “mock asteroid”.

The biggest real-life test of our planetary defenses was carried out in 2022, when NASA’s fridge-sized DART spacecraft smashed into a 160-metre (525-feet) wide asteroid, successfully knocking it well off course.

But for bigger asteroids, merely crashing spaceships into them will probably not do the trick.

When the roughly 10-kilometer wide Chicxulub asteroid struck the Yucatan peninsula around 66 million years ago, it is believed to have plunged Earth into darkness, sent kilometers-high tsunamis rippling around the globe and killed three quarters of all life—including wiping out the dinosaurs.

We humans are hoping to avoid a similar fate.

There is no current threat looming, but scientists have been working on how to stave off any big asteroids that could come our way in the future.

A leading theory has been to be blow them up with a nuclear bomb—a last-ditch plan famously depicted in the 1998 sci-fi action movie “Armageddon”.

In the movie, Bruce Willis and a plucky team of drillers save Earth from an asteroid 1,000 kilometers wide—roughly the size of Texas.

For a proof-of-concept study published in the journal Nature Physics this week, a team of US scientists worked on a much smaller scale, taking aim at a mock asteroid just 12 millimeters (half an inch) wide.

The asteroid Dimorphos streaks through the sky after being hit by NASA's DART spacecraft, which altered its trajectory
The asteroid Dimorphos streaks through the sky after being hit by NASA’s DART spacecraft, which altered its trajectory.

To test whether the theory would work, they used what was billed as the world’s largest X-ray machine at Sandia National Laboratories in Albuquerque, New Mexico.

The machine is capable of generating “the brightest flash of X-rays in the world using 80 trillion watts of electricity”, Sandia’s Nathan Moore, the lead study author, told AFP.

Much of the energy created by a nuclear explosion is in the form of X-rays. Since there is no air in space, there would be no shockwave or fireball.

But the X-rays still pack a powerful punch.

Turned into a ‘rocket engine’

For the lab experiment, the X-rays easily vaporized the surface of the mock asteroid.

The vaporizing material then propelled the mock asteroid in the opposite direction, so that it effectively “turned into a rocket engine,” Moore said.

It reached speeds of 250 kilometers an hour, “about as fast as a high-speed train,” he added.

The test marked the first time that predictions about how X-rays would affect an asteroid had been confirmed, Moore said.

An artist's illustration of the DART spacecraft heading towards the asteroid that it would smash into
An artist’s illustration of the DART spacecraft heading towards the asteroid that it would smash into.

“It really proves this concept could work.”

The scientists used modeling to scale up their experiment, estimating that X-rays from a nuclear blast could deflect an asteroid up to four kilometers wide—if given enough advanced notice.

The biggest asteroids are the easiest to detect ahead of time, so “this approach could be quite viable” even for asteroids the size of the dinosaur-killing Chicxulub, Moore said.

The experiment was based on using a one-megaton nuclear weapon. The largest ever detonated was the 50-megaton Soviet Tsar Bomba.

If there was to be a planet-saving mission in the future, the nuclear bomb would need to be placed within a few kilometers of the asteroid—and millions of kilometers away from Earth, Moore said.

Asteroids come in many flavors

Testing out the theory using a real nuke would be dangerous, hugely expensive—and banned by international treaties.

But there is still plenty to be discovered before such a high-risk test.

The largest uncertainty right now is that asteroids can “come in many flavors”, Moore said.

The asteroid Bennu, from which a NASA spacecraft collected samples and brought them back to Earth
The asteroid Bennu, from which a NASA spacecraft collected samples and brought them back to Earth.

“We have to be prepared for every scenario.”

For example, the asteroid hit by DART, Dimorphos, turned out to be a loosely held-together pile of rubble.

The European Space Agency’s Hera mission is scheduled to launch next month on a mission to find out more about its composition—and the finer details about how DART sent it packing.

Mary Burkey, a staff scientist at California’s Lawrence Livermore National Laboratory that was not involved in the new study, has run computer simulations about using nukes on asteroids.

She praised the study, saying that “being able to match my calculations to real-life data increases the credibility of my results.”

Her simulations have also demonstrated that such a mission “would be a very effective means to defend planet Earth”, Burkey told AFP.

“However, in order for it to work, there must be enough time after a mission for the extra push of velocity to move the asteroid’s trajectory off Earth.”

More information:
Nathan Moore, Simulation of asteroid deflection with a megajoule-class X-ray pulse, Nature Physics (2024). DOI: 10.1038/s41567-024-02633-7. www.nature.com/articles/s41567-024-02633-7

© 2024 AFP

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Nuking a huge asteroid could save Earth, lab experiment suggests (2024, September 25)
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Small firms may offer higher pay due to a lack of market power

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Small firms may offer higher pay due to a lack of market power


low wage work
Credit: Unsplash/CC0 Public Domain

Small companies may post higher wages for entry level positions than large companies—potentially attracting better talent, even though the larger companies have more influence on the market, according to new Cornell research.

“When firm productivity and worker skills are complementary, we actually want to see more-skilled workers at more-productive firms,” said Thomas Jungbauer, assistant professor of strategy and business economics in the Samuel Curtis Johnson Graduate School of Management, part of the SC Johnson College of Business.

And when firms hire similar numbers of workers, or when the applicant pool is large enough, we do in fact expect more-productive firms to post higher wages, thereby attracting more-qualified workers.

“But in high-skill labor markets, with a limited set of workers to choose from, market power matters,” he said, “because vacant positions within larger firms rival each other for workers.”

This rivalry may lead to mismatch through lower wages at big firms, according to Jungbauer, author of “Strategic Wage Posting, Market Power, and Mismatch,” published in the Journal of Labor Economics.

The other key finding: The benefits of offering different wages for the same job openings within a company are limited. “Even the small benefits of equal starting wages—from avoiding tensions or haggling over salaries—may compel firms not to post different wages for their vacancies,” he said.

Jungbauer began pondering this line of research nearly a decade ago, as a Ph.D. student at Northwestern University’s Kellogg School of Management. He was bothered, he said, by the fact that most of the research in this area only looked at one-to-one models, in which each firm hires a single worker, as opposed to scenarios in which firms have varying numbers of openings, and thus differ in their market power as is common in real-world labor markets.

“I was just irked by the fact that you have a model which doesn’t take into account that firms hiring needs are often very different for a myriad of reasons,” he said, “but all the early models assumed that every firm is hiring one worker.”

Jungbauer shows that when worker skills are fairly uniformly distributed, firms are indifferent between posting equal wages for all their openings and posting different wages. He shows that the presence of the above-mentioned labor market power, that is, firms hiring different numbers of workers, may have detrimental effects on the distribution of workers across firms.

More-productive firms may hire less-skilled workers than their smaller competitors because of a lack of “within-firm rivalry,” according to Jungbauer.

“While the openings of larger firms rival each other for workers,” he said, “these vacancies do not bid against each other, translating into lower wages in equilibrium.”

“If I’m a big firm, I’m hurting all my other vacancies if I post a higher wage,” Jungbauer said. “In equilibrium, I have less of an incentive to post high wages than a small firm with a single opening for example.”

Despite firms with more vacancies hiring less-skilled workers, Jungbauer finds, equilibrium wages are such that more productive firms always accrue higher profits. And added profit per worker decreases, so firms may want to reduce the number of their vacancies in order to obtain more-skilled workers.

It would stand to reason that the bigger, more productive firms got that way by hiring superior talent, but that’s not necessarily true, according to Jungbauer.

“A lot of market power initially originates from the output side,” he said. “Take Amazon, for example. A top entrepreneurial idea coupled with excellent execution exploded and much of the resulting market power translated to the input side.”

More information:
Thomas Jungbauer, Strategic Wage Posting, Market Power, and Mismatch, Journal of Labor Economics (2024). DOI: 10.1086/733046

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Small firms may offer higher pay due to a lack of market power (2024, September 25)
retrieved 25 September 2024
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