Extraordinary new material shows zero heat expansion from 4 to 1,400 K

 Australian researchers have created what may be one of the most thermally stable materials ever discovered. This new zero thermal expansion (ZTE) material made of scandium, aluminum, tungsten and oxygen did not change in volume at temperatures ranging from 4 to 1400 Kelvin (-269 to 1126 °C, -452 to 2059 °F).

That's a wider range of temperatures, say scientists from the University of New South Wales (UNSW), than any other material demonstrated to date, and it could make orthorhombic Sc_1.5Al_0.5W₃O₁₂ (catchy name, eh?) a very handy tool for anyone engineering something that needs to work in extremely varied thermal environments.

Examples of where this might come in handy include things like aerospace design, where components are exposed to extreme cold in space and extreme heat at launch or on re-entry. Famously, the SR-71 Blackbird was designed to expand so much at its Mach 3.4 top speed that it would liberally drizzle fuel on the runway at ground temperatures; the fuel tanks wouldn't even fully seal until they heated up. This new material stays exactly the same volume from close to absolute zero all the way up to comfortably over the heat you'd expect to get on the wing of a hypersonic aircraft traveling at Mach 5.

Or there's things like medical implants, where the range of expected temperatures isn't so varied but even a small amount of thermal expansion can cause critical issues.

The UNSW team made the discovery more or less by accident: "We were conducting experiments with these materials in association with our batteries-based research, for unrelated purposes, and fortuitously came across this singular property of this particular composition," says Associate Professor Neeraj Sharma.

 After measuring the material using the Echidna high-resolution powder diffractometer at ANSTO's Australian Synchrotron and the Australian Centre for Neutron Scattering, the team found an incredible degree of thermal stability. At the molecular level, materials usually expand because an increase in temperature leads directly to an increase in the length of the atomic bonds between elements. Sometimes it also causes atoms to rotate, resulting in more spacious structures that affect the overall volume.

Not with this stuff, which the team observed across that huge temperature spectrum demonstrating "only minute changes to the bonds, position of oxygen atoms and rotations of the atom arrangements." The team says the exact mechanism behind this extreme thermal stability isn't totally clear, but that perhaps bond lengths, angles and oxygen atom positions are changing in concert with one another to preserve the overall volume.

"Which part's acting at which temperature, well, that's the next question," says Sharma, who adds, “the scandium is rarer and more costly, but we are experimenting with other elements that might be substituted, and the stability retained,”

The other ingredients, however, are widely available, and bond together using a "relatively simple synthesis," so the team believes this material should present no impediments to large-scale manufacturing.

Source:https://lnkd.in/g-QqTDw

📢Spreading the Word!📢 Williams evolves composites-intensive EV platform!

 
Williams Advanced Engineering introduced its FW-EVX electric vehicle (EV) platform in 2017, designed to give vehicle manufacturers a modular system with which to develop new vehicles. 

''WAE reports that it is applying this innovative modular platform for use in a series of EVs with the top hats engineered for the vehicles by Italdesign, one of the leading transportation design and body engineering companies in the world.'' 

''The company's approach is, like many EV platforms being developed, skateboard-like in that the rolling chassis is integrated into a flat structure. However, what is different about the Williams solution is that the battery is housed in a molded composite case that is part of the vehicle load structure: front and rear chassis elements are attached to it. Crash loads are transferred through internal reinforcements that are within the side sills.'' 

To build this structure WAE is using both recycled composite material and aluminum; the company claims that the structure “sets new standards for static and torsional stiffness.” 

Source:Managing Composites

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Hints that century-old TB vaccine offers an immune boost against Covid-19

 There are indications that BCG revaccination might protect against Covid-19. The latest results come from a Greek study published as an as yet un-peer reviewed preprint on medRxiv.

BCG – Bacillus Calmette–Guérin – celebrates its 100th anniversary this summer and remains the only approved vaccine against tuberculosis. Developed by French bacteriologists Albert Calmette and Camille Guérin from a bovine relative of Mycobacterium tuberculosis, it was first given to an infant in a Parisian hospital in July 1921.

It was recognized early on that BCG vaccination appeared to reduce death from diseases beyond just tuberculosis. Immunologists have long suspected that this live vaccine primes the immune system to better fight infection. Last year, it was hypothesized that BCG vaccination may protect against Covid-19.

The Greek preprint – yet to be peer-reviewed – reported that BCG revaccination resulted in a 68% risk reduction for Covid-19 infection, clinically or virologically confirmed. Five patients receiving placebo developed the severe disease but just one in the BCG vaccine group. However, the trial was relatively small with only around 300 volunteers. ‘It is interesting data, but a small study with high loss to follow-up,’ says Frederik Schaltz-Buchholzer, an epidemiologist at the University of Southern Denmark, who is involved in the Danish BCG trials. ‘We shouldn’t be opening champagne bottles just yet. We have a lot of trials still going on.’

Data from large trials of BCG revaccination in healthcare workers are now in the works. However, in January, a Dutch study of 6132 patients drew attention to initial findings that the vaccine did not offer protection against Covid-19 symptoms in elderly people.

Immunologist Mihai Netea, who was involved in the Greek and Dutch study, says an important difference between them may be that older Greeks received the BCG vaccine as children, whereas people in countries such as Italy, the Netherlands and Belgium never received one. ‘It might be that the T cell response is different in those who have previously been exposed to BCG, and that the innate immune response is also boosted further by a second administration,’ says Netea, who led studies showing how BCG re-programs immune cells.

Large BCG trials for Covid are underway

Most of the BCG trials worldwide for Covid-19 are in healthcare workers, with more than 2500 volunteers in Brazil. These are part of the Brace trial, which has recruited over 7500 healthcare workers at 34 sites in Brazil, the Netherlands, Spain, the UK and Australia. This study is led by Nigel Curtis, a vaccine scientist at the Murdoch Children’s Research Institute and University of Melbourne, Australia, with support from the Bill & Melinda Gates Foundation. The main question posed is whether the off-target effects of BCG boosts innate immunity and thereby lessens the severity of Covid-19, says Curtis.

A trial of over 1200 healthcare workers is also underway in Denmark and a trial with older volunteers is still recruiting there. The former trial was stopped early because healthcare workers began receiving Covid-19 vaccines. This is an issue with other BCG trials carried out in Europe and the US, where trial participants became eligible for Sars-CoV-2 vaccines. Epidemiologists at the University Medical Centre Utrecht, the Netherlands, have now invited BCG trials to take part in a meta-analysis. The aim is to increase the statistical power by combining the data from all ongoing trials now, rather than waiting until the trials are finished, explains immunologist Henri van Werkhoven at Utrecht.

BCG is not the only existing live vaccine under evaluation. The Washington University School of Medicine in St Louis is coordinating an international trial to investigate if the measles, mumps, and rubella (MMR) vaccine protects healthcare workers from Sars-CoV-2. Also, a recent observational study from India suggests that an immune therapy with killed mycobacterium reduced hospitalizations from Covid-19.

‘BCG revaccination in countries with high-pressure load may be useful in countries where classical vaccines are not available. Of course, larger studies from developing countries would be needed to definitively prove that,’ comments Netea. Production of BCG would also need to be ramped up.

These results will be important for future pandemics ‘in order to get even a partial protection from the beginning, so you don’t have to close economies and have so much suffering’, Netea says. He adds that thankfully ‘we have other vaccines that are much more effective [for Covid-19], so the efforts should be put in there.

Source:MedRxiv/Chemistry world

Carbon Fiber Knife

 📢It's time for our segment Endless Possibilities!📢

Carbon fiber knives are awesome!

As a wise man once said: ''Carrying a CARBON FIBER KNIFE makes you 100% more self-sufficient.''

These knives are perfect for everybody, from the businessman to someone who lives in the jungle. They allow you to always finish the job WITH STYLE. After all, we know that there is nothing more beautiful than a carbon fiber look, right?

But be careful when buying one... Just because it looks like carbon, doesn't mean that it is actually carbon fiber!

Would you have one? Do you believe that they can have the same performance as other luxury knives? Let us know in the comments!

Fiberglass Manufacturing process

Today we will dive deeper into the fiberglass world! 🧐

As in a common soda-lime glass, the principal ingredient in all fiberglasses is silica (SiO2). Other oxides, such as B2O3 and Al2O3, are added to modify the network structure of SiO2 as well as to improve its workability. The internal structure of fiberglasses is a three-dimensional, long network of silicon, oxygen, and other atoms arranged randomly.

But how is fiberglass manufactured?

It all starts once raw materials are mixed and placed on a glass batch, which has a screw feeder that connects it to the tank, which is heated to melt the glass (>1370°C). The molten glass is fed into electrically heated bushings, which are generally made of platinum or metal alloy, with up to 3,000 very fine orifices. The molten glass passes through the orifices and comes out as fine filaments. Special binders are added and the strands are caught up on a high-speed winder.

The basic continuous commercial fiberglass is a strand. The strands can be turned into many different forms, such as rovings, woven fabrics, pre-impregnated fabrics, chopped strands, or even milled.

Bibliographical Reference:
Fiber Reinforced Composites – Materials, Manufacturing, and Design - Page 61

Chloroplasts enhanced with artificial dyes adsorb more solar energy

Modifying chloroplasts with aggregation-induced emission luminogens, known as AIEgens, makes them better at splitting water, separating electrons and generating adenosine triphosphate (ATP). The AIEgens, which were attached using click chemistry, enhance the chloroplasts by harvesting light that is normally inaccessible to regular photosynthetic pigments.

Chloroplasts are the light-driven metabolic factories of higher plant cells that produce carbohydrates and oxygen from carbon dioxide and water during photosynthesis. Chlorophyll A and Chlorophyll B are the main photosynthetic pigments within the chloroplasts. However, the adsorption spectrums of those pigments do not cover the whole solar radiation spectrum and means chloroplasts cannot harness all the solar energy available to them. Chloroplasts mainly adsorb blue and red light and are unable to harness light in the non-visible ultraviolet region, which can damage DNA and protein.

Now, a team led by Zhiyang Liu, Ryan Kwok and Ben Zhong Tang from the Hong Kong University of Science and Technology, has created two AIEgens that can harvest both ultraviolet radiation and photosynthetically inefficient radiation, and convert that radiation into blue and red light.

AIEgens are molecules that emit intense fluorescence when they aggregate together. The AIEgens developed by Liu, Kwok and Tang’s team contain activated alkyne groups derived from tetraphenylethylene and triphenylamine. These groups allowed the team to attach the AIEgens to live chloroplasts using a metal-free click reaction, based on the high reactivity between alkynes and amines.
‘In comparison to the natural chloroplasts, the two AIEgen-modified chloroplasts showed 30% and 50% increases in ATP production under our experimental conditions. We are learning from nature and meanwhile trying to go beyond nature. This work demonstrates that we can modify photosynthetic units and enhance solar energy utilisation in common plants,’ says Tang.

Eva-Mari Aro, from the University of Turku in Finland, whose research focuses on photosynthesis and bioenergy, says the work highlights the importance of materials scientists and photosynthesis researchers working together. ‘Solar energy is the most promising option for displacing fossil resources and promoting the systemic transition to sustainable green and renewable chemicals and fuels, produced directly from sunlight. New materials presented here for broadening the solar spectrum, useful in photosynthetic energy conversion, are very inspiring and promote not only the design towards efficient bio-hybrid devices but also other solar energy conversion devices making use of natural photosynthesis.’

References

H Bai et al, Mater. Horiz., 2021, 8, 1433 (DOI: 10.1039/d1mh00012h)