That’s because it is, in fact, sugar — very thin layers of confectioners’ sugar from the grocers, burnt to a state called carbon black, interspersed between only slightly thicker layers of silica, which is the most common material on Earth, and baked. The result resembles a fine layer cake, or more precisely, the organic and inorganic layering of a seashell, each layer helping the next to contain and mitigate shock.

“A material that can survive a variety of insults — mechanical, shock and X-ray — can be used to withstand harsh environmental conditions,” said Sandia researcher Guangping Xu, who led development of the new coating. “That material has not been readily available. We believe our layered nanocomposite, mimicking the structure of a seashell, is that answer.”

Most significantly, Xu said, “The self-assembled coating is not only lightweight and mechanically strong, but also thermally stable enough to protect instruments in experimental fusion machines against their own generated debris where temperatures may be about 1,500 C. This was the initial focus of the work.”

“And that may be only the beginning,” said consultant Rick Spielman, senior scientist and physics professor at the Laboratory for Laser Energetics at the University of Rochester, credited with leading the initial design of Sandia’s Z machine, one of the destinations for which the new material is intended. “There are probably a hundred uses we haven’t thought of.” He envisions possible electrode applications delaying, rather than blocking, surface electron emissions. Aiding the nuclear survivability mission

The coating, which can be layered on a variety of substrates without environmental problems, was the subject of a Sandia patent application in June 2021, an invited talk at a pulsed power conference in December 2021 and again in a recent technical article in MRS Advances, of which Xu is lead author.

The work was done in anticipation of the increased shielding that will be needed to protect test objects, diagnostics and drivers inside the more powerful pulsed power machines of the future. Sandia’s pulsed-power Z machine — currently the most powerful producer of X-rays on Earth — and its successors will certainly require still greater debris protection against forces that could compare to numerous sticks of dynamite exploding at close range. Chad McCoy loads sample coatings at Sandia’s Z machine

Physicist Chad McCoy at Sandia National Laboratories’ Z machine loads sample coatings into holders. When Z fires, researchers will observe how well particular coatings protect objects stacked behind them. (Photo by Bret Latter) Click the thumbnail for a high-resolution image.

“The new shielding should favorably impact our nuclear survivability mission,” said paper author and Sandia physicist Chad McCoy. “Z is the brightest X-ray source in the world, but the amount of X-rays is only a couple percent of the total energy released. The rest is shock and debris. When we try to understand how matter — such as metals and polymers — interacts with X-rays, we want to know if debris is damaging our samples, has changed its microstructure. Right now, we’re at the limit where we can protect sample materials from unwanted insults, but more powerful testing machines will require better shielding, and this new technology may enable appropriate protection.”

Other, less specialized uses remain possibilities.

The inexpensive, environmentally friendly shield is light enough to ride into space as a protective layer on satellites because comparatively little material is needed to achieve the same resilience as heavier but less effective shielding currently in use to protect against collisions with space junk. “Satellites in space get hit constantly by debris moving at a few kilometers per second, the same velocity as debris from Z,” McCoy said. “With this coating, we can make the debris shield thinner, decreasing weight.”

Thicker shield coatings are durable enough to strengthen the walls of pressurized vessels when added ounces are not an issue. Dramatic cost reduction anticipated

According to Guangping, the material cost to fabricate a 2-inch diameter coating of the new protective material, 45 millionths of a meter and microns thick, is only 25 cents. In contrast, a beryllium wafer — the closest match to the thermal and mechanical properties of the new coating, and in use at Sandia’s Z machine and other fusion locations as protective shields — costs $700 at recent market prices for a 1-inch square, 23-micron-thick wafer, which is 3,800 times more expensive than the new film of same area and thickness.

Both coatings can survive temperatures well above 1,000 C, but a further consideration is that the new coating is environmentally friendly. Only ethanol is added to facilitate the coating process. Beryllium creates toxic conditions, and its environs must be cleansed of the hazard after its use. How testing proceeded

The principle of alternating organic and inorganic layers, a major factor in seashell longevity, is key to strengthening the Sandia coating. The organic sugar layers burnt to carbon black act like a caulk, said Sandia manager and paper author Hongyou Fan. They also stop cracks from spreading through the inorganic silica structure and provide layers of cushioning to increase its mechanical strength, as was reported 20 years ago in an earlier Sandia attempt to mimic the seashell mode.

Greg Frye-Mason, Sandia campaign manager for the Assured Survivability and Agility with Pulsed Power, or ASAP, Laboratory Directed Research and Development mission campaign funding the research, initially had his doubts about the carbon insertion.

“I thought that the organic layers would limit applicability since most degrade by 400 to 500 C,” he said.

But when the carbon-black concept demonstrated robustness to well over 1,000 C, the positive result overcame the largest risk Frye-Mason saw as facing the project.

Seashell-like coatings initially tested at Sandia varied between a few to 13 layers. These alternating materials were pressed against each other after being heated in pairs, so their surfaces crosslinked. Tests showed that such interwoven nanocomposite layers of silica with the burnt sugar, known as carbon black after pyrolysis, are 80% stronger than silica itself and thermally stable to an estimated 1,650 C. Later sintering efforts showed that layers, self-assembled through a spin-coating process, could be batch-baked and their individual surfaces still crosslinked satisfactorily, removing the tediousness of baking each layer. The more efficient process achieved very nearly the same mechanical strength.

Research into the coating was funded by ASAP to develop methods to protect diagnostics and test samples on Z and on next-generation pulsed power machines from flying debris.

“This coating qualifies,” Frye-Mason said.

A new study published in BioMedical Engineering draws a link between mental illness and widely fluctuating blood pressure, which can lead to cardiovascular disease and organ damage.

UniSA researcher Dr Renly Lim and colleagues from Malaysian universities say there is clear evidence that mental illness interferes with the body’s autonomic functions, including blood pressure, heart rate, temperature and breathing.

“We reviewed 12 studies on people with anxiety, depression and panic disorders and found that, regardless of age, mental illness is significantly associated with greater blood pressure variations during the day,” Dr Lim says.

“We also found that for people who are mentally ill, their heart rate does not adapt to external stressors as it should.

“Contrary to what many people think, a healthy heart is not one that beats like a metronome. Instead, it should adjust to withstand environmental and psychological challenges. A constantly changing heart rate is actually a sign of good health.”

Reduced heart rate variation (HRV) is common in people with mental illness and indicates that the body’s stress response is poor, exacerbating the negative effects of chronic stress.

Unlike a person’s heart rate — how many times a heart beats in a minute — which is usually consistent, HRV is more complex and is the time between two heartbeats, which should change according to external stressors.

“What we aim for is not a constantly changing heart rate but a high heart rate variation. This is achieved through a healthy diet, exercise, low stress and good mental health.”

Low HRV occurs when a person’s body is in fight-or-flight mode, easily stressed and common in people with chronic diseases, including cardiovascular and mental health problems.

While large blood pressure variations (BPV) during the day are not ideal, at night the systolic pressure should dip by between 10-20 per cent to allow the heart to rest. The researchers found that in people with mental health issues, their blood pressure does not drop sufficiently at night.

The reduced dipping — under 10 per cent — can be caused by many factors, including autonomic dysfunction, poor quality of sleep and disrupted circadian rhythms that regulate the sleep-wake cycle.

“The takeout from this study is that we need to pay more attention to the physical impacts of mental illness,” Dr Lim says.

“It is a major global burden, affecting between 11-18 per cent (one billion) of people worldwide. Since mental illness can contribute to the deterioration of heart and blood pressure regulation, early therapeutic intervention is essential.”

The research was undertaken at the University of Malaya, University of South Australia, Universiti Kebangsaan Malaysia, and Universiti Tunku Abdul Rahman.

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Materials provided by University of South Australia. Note: Content may be edited for style and length.

Storms in the Sahel region, which can reach over 100km in size, have become more extreme since the 1980s due to global warming, with more intense rainfall.* Severe flooding during the monsoon from June to September causes human and livestock deaths, plus damages property and infrastructure, leaving thousands of people without homes and livelihoods.

State-of-the-art weather forecast models struggle to predict where new storms will hit and how strong they will be, which makes it difficult to provide warnings to people in affected areas so they can protect their property and livestock or get out of harm’s way.

National forecasting agencies in Africa can already make predictions of how storms will behave in the next couple of hours by observing current atmospheric conditions, and analysing hundreds of historical storms.

Now, thanks to a recent breakthrough by UKCEH scientists, they can make these short-term forecasts, known as ‘nowcasts’, for six hours ahead and with a higher degree of accuracy. The new research found drier soils can increase the intensity of storms when they are on the move, affecting where they travel and the amount of rainfall they produce.

These novel nowcasting predictions and related satellite observations for West Africa are available via UKCEH’s new free portal, which has been funded by the Natural Environment Research Council (NERC).

National forecasters can interpret the data and make localised forecasts, sending out warnings to people in areas that are expected to be hit by a storm. Last year, as part of a trial of the nowcasting tool, forecasters in Senegal used it to issue a severe weather warning to the public via text message.

Dr Steven Cole of UKCEH says: “The portal is a great example of how new scientific understanding can be translated into useable real-time tools by working with forecasters. Importantly, this will support communities in West Africa to better manage flood risk from intense rainfall.”

A recent study found that using data about land surface temperatures improves predictions about the path and strength of an approaching mesoscale convective system (MCS) up to 12 hours ahead. These ‘megastorms’ can be bigger than the size of England and unleash over 100mm of rainfall in just an hour.

“We found a surprising level of predictability of storms from land surface temperatures when testing our methodology on historical data, and West African forecasters are finding our approach very useful for their work,” says Professor Chris Taylor of UKCEH.

“We would expect mesoscale convective systems elsewhere in the world to also be influenced by drier soils. Therefore, our methodology could potentially be used to improve storm and flood warning systems in tropical regions such as South Asia and Australia, as well as parts of USA and South America.”

The new nowcasting portal allows forecasters to observe storm clouds in near real-time via satellite and compare them with historical storm behaviour, plus view data on current land surface conditions. The online tool then uses these data, updated every 15 minutes, to calculate the probability of a mesoscale convective system reaching different areas of the Sahel between the current time and six hours ahead.

UKCEH scientists are continuing to work with forecasting services in West Africa to increase the advance warning time and its reliability by combining more factors influencing storm behaviour within their nowcast modelling, in addition to land surface temperature. These include soil moisture, atmospheric humidity, wind conditions and the amount of rainfall there has been in preceding days.

As part of a collaboration with ANACIM, the national meteorological service in Senegal, UKCEH has also developed short-term forecasts of potential flood impacts and risk in Dakar which are available on the portal. It also hopes to work with other forecasting services to provide this service for other areas.