Comment

Comment by Dr. Krishna Kumari Challa on December 12, 2023 at 11:36am

Corrosion at atomic level

The cost of repairing corrosion worldwide is estimated at $2.5 trillion a year, which is more than 3% of the global GDP—so developing better ways to manage oxidation would be an economic boon.

When water vapor meets metal, the resulting corrosion can lead to mechanical problems that harm a machine's performance. Through a process called passivation, it also can form a thin inert layer that acts as a barrier against further deterioration.

A technique called environmental transmission electron microscopy (TEM),  allows researchers to directly view molecules interacting on the tiniest possible scale.

Researchers  introduced water vapour to clean aluminum samples and observed the surface reactions. They discovered something that had never been observed before: In addition to the aluminum hydroxide layer that formed on the surface, a second amorphous layer developed underneath it, which indicates there is a transport mechanism that diffuses oxygen into the substrate.

Understanding how a water molecule's hydrogen and oxygen atoms break apart to interact with metals could lead to clean-energy solutions.

Xiaobo Chen et al, Atomistic mechanisms of water vapor–induced surface passivation, Science Advances (2023). DOI: 10.1126/sciadv.adh5565

Comment by Dr. Krishna Kumari Challa on December 12, 2023 at 10:39am

Scientists are trying to test this now . They are trying to   launch a rocket from Alaska through these phenomena and measure the strength and direction of the electric and magnetic fields. SSL scientists specialize in designing and building instruments that do just that. Many of these instruments are on spacecraft now orbiting Earth and the sun.

Initially, the target would be what's known as an enhanced aurora, which is a normal aurora with picket fence-like emissions embedded in it.

The enhanced aurora is basically this bright layer that's embedded in the normal aurora. The colors are similar to the picket fence in that there's not as much blue in them, and there's more green from oxygen and red from nitrogen. The hypothesis is that these are also created by parallel electric fields, but they are a lot more common than the picket fence.

The plan is not only to fly a rocket through that enhanced layer to actually measure those parallel electric fields for the first time but also to distinguish the conditions from those that cause the auroras. Eventually, researchers hope  for a rocket that will fly directly through Steve and the picket fence.

 L. Claire Gasque et al, It's Not Easy Being Green: Kinetic Modeling of the Emission Spectrum Observed in STEVE's Picket Fence, Geophysical Research Letters (2023). DOI: 10.1029/2023GL106073

Part 3

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Comment by Dr. Krishna Kumari Challa on December 12, 2023 at 10:35am

The common auroras are produced when the solar wind energizes particles in Earth's magnetosphere, often at altitudes higher than 1,000 kilometers above the surface. These energized particles spiral around Earth's magnetic field lines toward the poles, where they crash into and excite oxygen and nitrogen molecules in the upper atmosphere. When those molecules relax, oxygen emits specific frequencies of green and red light, while nitrogen generates a bit of red, but primarily a blue, emission line.

The colorful, shimmering curtains that result can extend for thousands of kilometers across the northern or southern latitudes.

Steve, however, displays not individual emission lines, but a broad range of frequencies centered around purple or mauve. And unlike auroras, neither Steve nor the picket fence emit blue light, which is generated when the most energetic particles hit and ionize nitrogen. Steve and the picket fence also occur at lower latitudes than the aurora, potentially even as far south as the equator.

Some researchers proposed that Steve is caused by ion flows in the upper atmosphere, referred to as subauroral ion drift, or SAID, though there's no well accepted physical explanation for how SAID could generate the colorful emissions.

There are also other suggestions that the picket fence's emissions could be generated by low-altitude electric fields parallel to Earth's magnetic field, a situation thought to be impossible because any electric field aligned with the magnetic field should quickly short out and disappear.

One model showed that a moderate parallel electric field—around 100 millivolts per meter—at a height of about 110 km could accelerate electrons to an energy that would excite oxygen and nitrogen and generate the spectrum of light observed from the picket fence. Unusual conditions in that area, such as a lower density of charged plasma and more neutral atoms of oxygen and nitrogen, could potentially act as insulation to keep the electric field from shorting out.

If you look at the spectrum of the picket fence, it's much more green than you would expect. And there's none of the blue that's coming from the ionization of nitrogen. What that's telling us is that there's only a specific energy range of electrons that can create those colors, and they can't be coming from way out in space down into the atmosphere, because those particles have too much energy.

Instead the light from the picket fence is being created by particles that have to be energized right there in space by a parallel electric field, which is a completely different mechanism than any of the aurora that researchers have studied or known before.

They also suspect that Steve itself may be produced by related processes. Their calculations also predict the type of ultraviolet emissions that this process would produce, which can be checked to verify the new hypothesis about the picket fence.

Though some calculations don't directly address the on-off glow that makes the phenomenon look like a picket fence, it's likely due to wavelike variations in the electric field. And while the particles that are accelerated by the electric field are probably not from the sun, the scrambling of the atmosphere by solar storms  probably triggers Steve and the picket fence, as it does the common aurora.

Part 2

Comment by Dr. Krishna Kumari Challa on December 12, 2023 at 10:00am

Phenomena called 'Steve' and 'picket fence' are masquerading as auroras

The shimmering green, red and purple curtains of the northern and southern lights—the auroras—may be the best-known phenomena lighting up the nighttime sky, but the most mysterious are the mauve and white streaks called Steve and their frequent companion, a glowing green "picket fence."

First recognized in 2018 as distinct from the common auroras, Steve and its associated picket fence were nevertheless thought to be caused by the same physical processes. But scientists were left scratching their heads about how these glowing emissions were produced.

Vibrant auroras and glowing phenomena such as Steve and the picket fence are becoming more common as the sun enters the active period of its 11-year cycle.

Because all these transient luminous phenomena are triggered by solar storms and coronal mass ejections from the sun, the approaching solar maximum is an ideal time to study rare events like Steve and the picket fence.

In a region of the upper atmosphere farther south than that in which auroras form, electric fields parallel to Earth's magnetic field could produce the color spectrum of the picket fence. If correct, this unusual process has implications for how physicists understand energy flow between Earth's magnetosphere, which surrounds and protects Earth from the solar wind, and the ionosphere at the edge of space.

A new  paper  showed that parallel electric fields are capable of explaining this exotic spectrum.

Part 1

Comment by Dr. Krishna Kumari Challa on December 12, 2023 at 9:50am

Biocrusts on Great Wall of China found to be protecting it from erosion

A small international team of soil and water ecosystem conservation specialists has found that biocrusts clinging to parts of the Great Wall of China have been serving to protect the famous structure from erosion. In their paper published in the journal Science Advances (1), the group describes their study and analysis of material growing on the wall.

The Great Wall of China was built over several centuries starting approximately 221 BC—its function was to protect the people living behind it from enemies attempting to invade from the other side. Prior research has shown that different parts of the wall were made with different materials—mostly rammed earth or stone.

Rammed earth is made by mixing organic materials with inorganic materials. Because of their nature, such materials are more susceptible to erosion. That has led to questions regarding how sections of the wall made with the material have survived for so many years. In this new effort, the researchers wondered if perhaps biocrusts may have played a role.

For many years, scientists have assumed that such biocrusts, which are generally made of cyanobacteria, lichen and mosses, speed up the erosion process. To find out if that is the case, the research team collected samples of the biocrusts from several points along the wall and brought them back to a lab for study.

The researchers measured the mechanical strength and soil stability of the samples. They also tested parts of the wall directly comparing those covered in biocrusts and those that were directly exposed to the elements.

They found that the biocrusts were stronger than the rammed earth material upon which they were growing—in some cases, three times as strong. The researchers also found the strength in the biocrusts was due to secretion of tightly bound polymers.

The research team concluded that rather than speeding up erosion, the biocrusts have been slowing the process, helping to preserve the famed structure. Somewhat analogous to their findings were those by a team from the University of Granada working in Honduras that found that organic plant materials added to plasters by early Mayan people have served to reduce weathering of the stone structures they built(2). 

Footnotes:

1.Yousong Cao et al, Biocrusts protect the Great Wall of China from erosion, Science Advances (2023). DOI: 10.1126/sciadv.adk5892

2. Carlos Rodriguez-Navarro et al, Unveiling the secret of ancient Maya masons: Biomimetic lime plasters with plant extracts, Science Advances (2023). DOI: 10.1126/sciadv.adf6138

Comment by Dr. Krishna Kumari Challa on December 10, 2023 at 1:50pm

Modelling the effects of this pulse through the Earth System shows that this new, suddenly disrupted, climate pattern is here for at least 50,000 years and probably far longer. It's a large part of the way our planet has changed fundamentally and irreversibly, to become comparable to some of the great climate change events in deep Earth history.

So will this particular COP meeting, with fossil fuel interests so strongly represented, make a difference? The bottom line is that attaining, and stabilising carbon emissions at "net zero" is only a crucial first step.

This latest warming step has already taken the Earth into levels of climate warmth not experienced for some 120,000 years, into those of the last interglacial phase, a little warmer than the current one. There is yet more warming in the pipeline over coming centuries, as various feedbacks take effect. A recent study on the effects of this warming on Antarctica's ice suggests that "policymakers should be prepared for several metres of sea-level rise over the coming centuries" as the pulse of warmth spreads through the oceans to undermine the great polar ice-sheets.

https://theconversation.com/the-climate-change-we-caused-is-here-fo...

Part 2

Comment by Dr. Krishna Kumari Challa on December 10, 2023 at 1:48pm

The Climate Change We've Already Created Will Last 50,000 Years, Scientists Warn

The idea of an entirely new and human-created geological epoch is a sobering scenario as context for the current UN climate summit, COP28. The impact of decisions made at these and other similar conferences will be felt not just beyond our own lives and those of our children, but perhaps beyond the life of human society as we know it.

Enormous deforestation, the mushrooming of dams across the world's large rivers, overfishing, a planet's nitrogen cycle overwhelmed by fertiliser use, the rapid rise in greenhouse gases.....

As for climate change itself, well, the warning bells were ringing, certainly. Global mean surface temperatures had risen by about half a degree since the mid-20th century. But, they were still within the norm for an interglacial phase of the ice ages. Among many emerging problems, climate seemed one for the future.

A little more than two decades on, the future has arrived. By 2022, global temperature had climbed another half a degree, the past nine years being the hottest since records began. And 2023 has seen climate records being not just broken, but smashed.

With this leap in temperatures came record-breaking heatwaves, wildfires and floods, exacerbated by other local human actions. Climate has moved centre stage on an Anthropocene Earth.

To see how this might play out on a geological timescale, we need to look through the lens of the Anthropocene. A delicately balanced planetary machinery of regular, multi-millennial variations in the Earth's spin and orbit has tightly controlled patterns of warm and cold for millions of years.

Now, suddenly, this control machinery has been overridden by a trillion tons of carbon dioxide injected into the atmosphere in little more than a century.

Part 1

Comment by Dr. Krishna Kumari Challa on December 9, 2023 at 11:31am

‘Tweezers’ hold quantum molecule
Physicists have used lasers as ‘optical tweezers’ to position molecules so precisely that the molecules can be used as qubits to process quantum information. Pairs of calcium monofluoride molecules were gingerly manoeuvred so that they became entangled and behaved as a single collective quantum system. The molecules were cooled to close to absolute zero, making them almost completely still. When their rotation was completely stopped, they represented the ‘0’ state of the qubit. Meanwhile, molecules allowed to rotate with just one quantum of rotational momentum represented the ‘1’ state. Molecules have some advantages over other qubit candidates, such as atoms. For example, molecules could be pushed into service as ‘qutrits’, which have three possible states: −1, 0 and +1.

https://www.science.org/doi/10.1126/science.adf8999

https://www.science.org/doi/10.1126/science.adf4272

Comment by Dr. Krishna Kumari Challa on December 9, 2023 at 10:35am

Catalyst makes drugs inside the body to minimize side effects

A highly active catalyst capable of synthesizing drug molecules within the body has been developed by  chemists. In mice, an anticancer drug assembled near tumors using the injected catalyst suppressed tumour growth.

In conventional medicines delivered by injection or pill, the active drug molecule circulates throughout the body, flooding not only the target site but also healthy tissues. The resulting side effects can be so serious that they can cause permanent damage and force treatment to be stopped. Assembling drug molecules at target sites within the body could make them more effective while minimizing their side effects.

The direct synthesis of drugs in the body would enable drugs to treat diseases without causing side effects in healthy tissues. That's why we need a biocompatible biocatalysis system to perform drug synthesis near target sites in the body.

The team targeted drug assembly in the body using a catalytic chemical reaction called olefin metathesis. Olefin metathesis is one of the most efficient methods for constructing carbon–carbon double bonds for synthesizing drugs. If it could be worked out in the body, it should enable us to synthesize many different types of drugs.

Most chemical catalysts are rapidly deactivated by biomolecules in the bloodstream. To overcome this problem, the team wrapped a ruthenium-based olefin metathesis catalyst inside a protective protein called human serum albumin.

Tanaka's team had previously shown that a ruthenium chloride complex embedded inside human serum albumin—forming a catalytic assembly called an artificial metalloenzyme—was somewhat active in blood. Now, they have shown that switching to a ruthenium iodide complex produces a far superior artificial metalloenzyme.

At low catalyst concentrations, the new albumin-based ruthenium iodide (AlbRuI) catalyst catalyzed three types of olefin metathesis reactions in blood at high yield.

AlbRuI also showed robust stability for 24 hours in blood.This expands the biocompatibility of artificial metalloenzymes and opens the door for developing general, metal-based artificial metalloenzymes for catalytic reactions in blood.

The team also showed that a low dose of cancer-targeting AlbRuI significantly inhibited tumour growth in mice through localized synthesis of an antitumour drug.

 Igor Nasibullin et al, Catalytic olefin metathesis in blood, Chemical Science (2023). DOI: 10.1039/D3SC03785A

Comment by Dr. Krishna Kumari Challa on December 9, 2023 at 10:27am

Rich nations need to ditch fossil fuels by 2040: scientists

Rich countries need to stop using coal by 2030 and oil and gas by 2040, with poorer nations following a decade behind, to give the world a chance of limiting warming to 1.5C, climate scientists told the UN this week.

In a note to the UN Secretary-General Antonio Guterres and UN Climate Change body, shared with AFP, climate scientists said there was very little room for anything but a total phase-out of fossil fuels.

The steep timeline they laid out comes as climate negotiators at the COP28 talks in Dubai are tussling over the future of oil, gas and coal, responsible for the lion's share of humanity's planet-heating emissions.

The UN climate negotiations are tasked with helping the world meet the Paris deal goal of limiting global warming to 1.5 degrees Celsius from pre-industrial levels, but have often been vague on how that target will be achieved.

The discussions should be around serious and fair efforts to start implementing a phase out plan: scientists

Source: AFP

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Israel's AI can produce 100 bombing targets a day in Gaza. Is this ...

Last week, reports emerged that the Israel Defense Forces (IDF) are using an artificial intelligence (AI) system called Habsora (Hebrew for "The Gospel") to select targets in the war on Hamas in Gaza. The system has reportedly been used to find more targets for bombing, to link locations to Hamas operatives, and to estimate likely numbers of civilian deaths in advance.

https://theconversation.com/israels-ai-can-produce-100-bombing-targ...

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