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Blog – Page 7274

A new study lead by GSI scientists and international colleagues investigates black-hole formation in neutron star mergers. Computer simulations show that the properties of dense nuclear matter play a crucial role, which directly links the astrophysical merger event to heavy-ion collision experiments at GSI and FAIR. These properties will be studied more precisely at the future FAIR facility. The results have now been published in Physical Review Letters. With the award of the 2020 Nobel Prize in Physics for the theoretical description of black holes and for the discovery of a supermassive object at the center of our galaxy, the topic currently also receives a lot of attention.

But under which conditions does a black hole actually form? This is the central question of a study lead by the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt within an international collaboration. Using , the scientists focus on a particular process to form namely the merging of two stars.

Neutron stars consists of highly compressed dense matter. The mass of one and a half is squeezed to the size of just a few kilometers. This corresponds to similar or even higher densities than in the inner of atomic nuclei. If two neutron stars merge, the matter is additionally compressed during the collision. This brings the merger remnant on the brink to collapse to a black hole. Black holes are the most compact objects in the universe, even light cannot escape, so these objects cannot be observed directly.

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A team of researchers at Samsung has developed a slim-panel holographic video display that allows for viewing from a variety of angles. In their paper published in the journal Nature Communications, the group describes their new display device and their plans for making it suitable for use with a smartphone.

Despite predictions in science-fiction books and movies over the past several decades, 3D holographic players are still not available to consumers. Existing players are too bulky and display video from limited viewing angles. In this new effort, the researchers at Samsung claim to have overcome these difficulties and built a demo device to prove it.

To build their demo device, which was approximately 25 cm tall, the team at Samsung added a steering-backlight unit with a beam deflector for increasing viewing angles. The demo had a viewing angle of 15 degrees at distances up to one meter. The beam deflector was made by sandwiching liquid crystals between sheets of glass. The end result was a device that could bend the light that came through it very much like a prism. Testing showed the beam deflector combined with a tilting mechanism increased viewing angles by 30 times compared to conventional designs. The new design also allows for a slim form at just 1 cm thick. It also has a light modulator, geometric lens and a holographic video processor capable of carrying out 140 billion operations per second. The researchers used a new algorithm that uses lookup tables rather than math operations to process the video data. The demo device was capable of displaying 4K resolution holographic video running at 30 frames per second.

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Nanographene is a material that could radically improve solar cells, fuel cells, LEDs and more. Typically, the synthesis of this material has been imprecise and difficult to control. For the first time, researchers have discovered a simple way to gain precise control over the fabrication of nanographene. In doing so, they have shed light on the previously unclear chemical processes involved in nanographene production.

Graphene, one-atom-thick sheets of carbon molecules, could revolutionize future technology. Units of graphene are known as ; these are tailored to specific functions, and as such, their fabrication process is more complicated than that of generic graphene. Nanographene is made by selectively removing from organic molecules of carbon and hydrogen, a process called dehydrogenation.

“Dehydrogenation takes place on a such as that of silver, gold or copper, which acts as a catalyst, a material that enables or speeds up a reaction,” said Assistant Professor Akitoshi Shiotari from the Department of Advanced Materials Science. “However, this surface is large relative to the target organic molecules. This contributes to the difficulty in crafting specific nanographene formations. We needed a better understanding of the catalytic process and a more precise way to control it.”

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Even with decades of unprecedented development in computational power, the human brain still holds many advantages over modern computing technologies. Our brains are extremely efficient for many cognitive tasks and do not separate memory and computing, unlike standard computer chips.

In the last decade, the new paradigm of neuromorphic computing has emerged, inspired by neural networks of the brain and based on energy-efficient hardware for information processing.

To create devices that mimic what occurs in our brain’s neurons and synapses, researchers need to overcome a fundamental molecular engineering challenge: how to design devices that exhibit controllable and energy-efficient transition between different resistive states triggered by incoming stimuli.

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Engineers at Cornell University have developed a new technique for 3D printing metallic objects – and it involves blasting titanium particles at supersonic speeds. The resulting metals are very porous, which makes them particularly useful for biomedical objects like implants and replacement joints.

Traditional 3D printing involves a nozzle depositing plastic, hydrogels, living cells or other materials layer by layer to build up an object. Metal parts and objects are usually 3D printed in other ways, such as firing a laser at a bed of metal powder to selectively melt sections into the desired shape, or firing metal powder at high speeds at a substrate to fuse the particles together.

The latter method is known as “cold spray,” and the new technique expands on that base. The Cornell team blasted titanium alloy particles, each measuring between 45 and 106 microns wide, at speeds up to 600 m (1,969 ft) per second (for reference, the speed of sound in air is around 340 m (1,115 ft) per second). The team calculated this as the ideal speed – any faster, and the particles would disintegrate too much on impact to bond to each other.

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Aging link

~~~ “The telomere biology of humans is closer to the telomere biology of birds than those of traditional laboratory models. In both humans and birds, telomere length is measured in a minimally-invasive way from small blood samples,” says Collegium Researcher Antoine Stier from the University of Turku (Finland), the main author of the research article.

While authors of the study had reasons to expect shorter telomeres in chicks born from eggs injected with thyroid hormones, they were quite surprised to find that those chicks actually exhibited longer telomeres right after birth.” “Based on the natural decline of telomere length observed with age in the same collared flycatcher population, we estimated that chicks hatching from thyroid hormones injected eggs were approximately four years younger at birth than chicks hatched from control eggs,” adds Collegium Researcher Suvi Ruuskanen.

Although the molecular mechanisms underlying such effects remain to be discovered, the new findings suggest that prenatal thyroid hormones might have a role in setting the ‘biological age’ at birth.

Continue reading “Born to be young? Prenatal thyroid hormones influence ‘biological age’ at birth” | >