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A team of researchers from Zhejiang University, Xi’an Jiaotong University and Monash University has developed a way to bind multiple strands of graphene oxide into a thick cable. In their paper published in the journal Science, the group describes their process and possible uses for it. Rodolfo Cruz-Silva and Ana Laura Elías with Shinshu University and Binghamton University have published a Perspectives piece in the same issue outlining the work by the researchers and explaining why they believe the technique could prove useful in manufacturing efforts.

In recent years, materials scientists have been exploring the possibility of making products using total or partial self-assembly as a way to produce them faster or at less cost. In biological systems where two materials self-assemble into a third material, scientists describe this as a fusion process, borrowing terminology from physics. So when a single material spontaneously separates into two or more other materials, they refer to it as a fission process. In this new effort, the researchers have developed a technique for creating graphene-oxide-based yarn that exploits both processes.

The work by the team is very basic. They created multiple strands of graphene oxide and then dunked them into a solvent solution for 10 minutes. When the strands were pulled from the solution, they banded together forming a cord, or single strand of yarn. They also developed a means for reversing the process—dunking the strand of yarn in a different solvent solution.

The intractable “three-body problem” gets closer to being solved with breakthrough study.

Past physics theories introduced several fundamental constants, including Newton’s constant G, which quantifies the strength of the gravitational interaction between two massive objects. Combined, these fundamental constants allow physicists to describe the universe in ways that are straightforward and easier to understand.

In the past, some researchers wondered whether the value of fundamental constants changed over cosmic time. Moreover, some alternative theories of gravity (i.e., adaptations or substitutes of Einstein’s theory of general relativity), predict that the constant G varies in time.

Researchers at the International Centre for Theoretical Sciences of the Tata Institute for Fundamental Research in India recently proposed a method that can be used to place constraints on the variation of G over cosmic time. This method, outlined in a paper published in Physical Review Letters, is based on observations of merging binary neutron stars.

A team of international scientists, led by the Galician Institute of High Energy Physics (IGFAE) and the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), has proposed a simple and novel method to bring the accuracy of the Hubble constant measurements down to 2% using a single observation of a pair of merging neutron stars.

The universe is in continuous expansion. Because of this, distant objects such as galaxies are moving away from us. In fact, the further away they are, the faster they move. Scientists describe this expansion through a famous number known as the Hubble constant, which tells us how fast objects in the universe recede from us depending on their distance to us. By measuring the Hubble constant in a precise way, we can also determine some of the most fundamental properties of the universe, including its age.

For decades, scientists have measured Hubble’s constant with increasing accuracy, collecting electromagnetic signals emitted throughout the universe but arriving at a challenging result: the two current best measurements give inconsistent results. Since 2015, scientists have tried to tackle this challenge with the science of gravitational waves, ripples in the fabric of space-time that travel at the speed of light. Gravitational waves are generated in the most violent cosmic events and provide a new channel of information about the universe. They’re emitted during the collision of two neutron stars —the dense cores of collapsed stars —and can help scientists dig deeper into the Hubble constant mystery.

A dynamo mechanism could explain the incredibly strong magnetic fields in white dwarf stars according to an international team of scientists, including a University of Warwick astronomer.

One of the most striking phenomena in astrophysics is the presence of magnetic fields. Like the Earth, stars and stellar remnants such as white dwarfs have one. It is known that the magnetic fields of white dwarfs can be a million times stronger than that of the Earth. However, their origin has been a mystery since the discovery of the first magnetic white dwarf in the 1970s. Several theories have been proposed, but none of them has been able to explain the different occurrence rates of magnetic white dwarfs, both as individual stars and in different binary star environments.

This uncertainty may be resolved thanks to research by an international team of astrophysicists, including Professor Boris Gänsicke from the University of Warwick and led by Professor Dr. Matthias Schreiber from Núcleo Milenio de Formación Planetaria at Universidad Santa María in Chile. The team showed that a dynamo mechanism similar to the one that generates magnetic fields on Earth and other planets can work in white dwarfs, and produce much stronger fields. This research, part-funded by the Science and Technology Facilities Council (STFC) and the Leverhulme Trust, has been published in the prestigious scientific journal Nature Astronomy.

Chemical organization in reaction-diffusion systems offer a strategy to generate materials with ordered morphologies and architecture. Periodic structures can be formed using molecules or nanoparticles. An emerging frontier in materials science aims to combine nanoparticles and molecules. In a new report on Science Advances, Amanda J. Ackroyd and a team of scientists in chemistry, physics and nanomaterials in Canada, Hungary and the U.S. noted how solvent evaporation from a suspension of cellulose nanocrystals (CNCs) and L-(+)-tartaric acid [abbreviated L-(+)-TA] caused the phase separation of precipitation to result in the rhythmic alteration of CNC-rich, L-(+)-TA rings. The CNC-rich regions maintained a cholesteric structure, while the L-(+)-TA-rich bands formed via radially elongated bundles to expand the knowledge of self-organizing reaction-diffusion systems and offer a strategy to design self-organizing materials.

Chemical organization

The process of self-organization and self-assembly occurs universally in non-equilibrium systems of living matter, geochemical environments, materials science and in industry. Existing experiments that lead to periodic structures can be divided into two groups including the classical Liesegang-type experiments and chemical organization via periodic precipitation to generate materials with ordered morphologies and structural hierarchy. In this work, Ackroyd et al. developed a strategy for solvent evaporation to phase separate an aqueous solution of tartaric acid/cellulose nanocrystals [L-(+)-TA/CNC or TA/CNC] for its subsequent precipitation to result in a rhythmic alternation of CNC-rich or CNC-depleted ring-type regions. The team developed a kinetic model which agreed with the experimental results quantitatively. The work expands the range of self-organizing reaction-diffusion systems to pave the way for periodically structured functional materials.

An international research team led by Michigan State University has helped create cosmic conditions at RIKEN’s heavy-ion accelerator in Japan.

Imagine taking all of the water in Lake Michigan — more than a quadrillion gallons — and squeezing it into a 4-gallon bucket, the kind you’d find at a hardware store.

A quick review of the numbers suggests that this should be impossible: that’s too much stuff and not enough space. But this outlandish density is a defining feature of celestial objects known as neutron stars. These stars are only about 15 miles across, yet they hold more mass than our sun thanks to some extreme physics.

A breakthrough astrophysics code, named Octo-Tiger, simulates the evolution of self-gravitating and rotating systems of arbitrary geometry using adaptive mesh refinement and a new method to parallelize the code to achieve superior speeds.

This new code to model stellar collisions is more expeditious than the established code used for numerical simulations. The research came from a unique collaboration between experimental computer scientists and astrophysicists in the Louisiana State University Department of Physics & Astronomy, the LSU Center for Computation & Technology, Indiana University Kokomo and Macquarie University, Australia, culminating in over of a year of benchmark testing and scientific simulations, supported by multiple NSF grants, including one specifically designed to break the barrier between computer science and astrophysics.

“Thanks to a significant effort across this collaboration, we now have a reliable computational framework to simulate stellar mergers,” said Patrick Motl, professor of physics at Indiana University Kokomo. “By substantially reducing the computational time to complete a simulation, we can begin to ask new questions that could not be addressed when a single-merger simulation was precious and very time consuming. We can explore more parameter space, examine a simulation at very high spatial resolution or for longer times after a merger, and we can extend the simulations to include more complete physical models by incorporating radiative transfer, for example.”

O,.o.

Livescience.com | By LIVESCIENCE

Gravitational wave detectors could soon uncover hints of new physics from exotic compact objects.