Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: materials – Page 138

Thermoelectric devices convert thermal energy into electricity by generating a voltage from the difference in temperature between the hot and cold parts of a device.

To better understand how the conversion process occurs at the atomic scale, researchers used neutrons to study single crystals of tin sulfide and tin selenide. They measured changes that were dependent on temperature.

The measurements revealed a strong correlation between changes in the structure at certain temperatures and the frequency of atomic vibrations (phonons). This relationship affects how the materials conduct heat.

Read more | >

An unusual protein structure known as a “rippled beta sheet,” first predicted in 1953, has now been created in the laboratory and characterized in detail using X-ray crystallography.

The new findings, published in July in Chemical Science, may enable the rational design of unique materials based on the rippled sheet architecture.

“Our study establishes the rippled beta sheet layer configuration as a motif with general features and opens the road to structure-based design of unique molecular architectures, with potential for materials development and ,” said Jevgenij Raskatov, associate professor of chemistry and biochemistry at UC Santa Cruz and corresponding author of the paper.

Read more | >

A multidisciplinary team of Indiana University researchers have discovered that the motion of chromatin, the material that DNA is made of, can help facilitate effective repair of DNA damage in the human nucleus—a finding that could lead to improved cancer diagnosis and treatment. Their findings were recently published in the Proceedings of the National Academy of Sciences.

DNA damage happens naturally in and most of the damage can be repaired by the cell itself. However, unsuccessful repair could lead to cancer.

“DNA in the nucleus is always moving, not static. The motion of its high-order complex, chromatin, has a direct role in influencing DNA repair,” said Jing Liu, an assistant professor of physics in the School of Science at IUPUI. “In yeast, past research shows that DNA damage promotes chromatin motion, and the high mobility of it also facilitates the DNA repair. However, in human cells this relationship is more complicated.”

Read more | >

Atoms in magnetic materials are organized into regions called magnetic domains. Within each domain, the electrons have the same magnetic orientation. This means their spins point in the same direction. “Walls” separate the magnetic domains. One type of wall has spin rotations that are left-or right-handed, known as having chirality. When subjected to a magnetic field, chiral domain walls approach one another, shrinking the magnetic domains.

Researchers have developed a magnetic material whose thickness determines whether chiral domain walls have the same or alternating handedness. In the latter case, applying a leads to annihilation of colliding domain walls. The researchers combined and electron microscopy to characterize these internal, microscopic features, leading to better understanding of the magnetic behavior.

An emerging field of technology called spintronics involves processing and storing information by harnessing an electron’s spin instead of its charge. The ability to control this fundamental property could unlock new possibilities for developing electronic devices. Compared to current technology, these devices could store more information in less space and operate at higher speeds with less energy consumption.

Read more | >

The discovery of high temperature superconductors in polyhydrides encourages searching for new types of hydrogen rich superconductors. Most of experimentally reported high Tc polyhydride superconductors are binary hydrides of main group elements, rare earth metals (La, Y etc.) or alkali earth metal (Ca).

Prof. Jin team at Institute of Physics of Chinese Academy of Sciences (IOPCAS) recently discovered new hafnium polyhydrides using synergetic techniques based on diamond anvil cell in combination with in situ laser heating during a search for new types of hydrogen rich superconducting materials.

“The hafnium polyhydrides are synthesized at 243GPa and 2000 K high pressure high temperature conditions and exhibits superconductivity with Tc ~83 K at 243GPa,” explained coauthor Xiancheng Wang who is a professor at IOPCAS. The upper critical field was estimated to be ~24 Tesla while the Ginzburg Landau superconducting coherent length obtained is ~37Å.

Read more | >

Inserting any material into a special maze of mirrors and lenses can make it absorb light perfectly. This approach could be used to detect faint starlight or for charging faraway devices with lasers.

Ori Katz at the Hebrew University of Jerusalem in Israel and his colleagues created an almost perfect absorber of light by building an “anti-laser”.

In a laser, light bounces between mirrors until it becomes amplified enough to exit the device in a concentrated beam. In an “anti-laser”, says co-author Stefan Rotter at Vienna University of Technology in Austria, light enters the device then gets stuck in an inescapable series of bounces within it.

Read more | >

Ancient engineers might have built a canal on the Nile.

No one has solved the mystery of the Giza pyramids for centuries. Although archaeologists and scientists have tried to reveal how they were made over the years, it is difficult to say the “exact method” for sure. However, very recently, an idea has been put forward by researchers about how the pyramids were built.

According to a recent study — published in PNAS in August. 29 —the pyramids of Giza may have been built using a former arm of the Nile River. This river branch would have served as a navigable route for the transportation of goods not previously known.

The pyramids of Giza constitute one of the world’s most iconic cultural landscapes and have fascinated humanity for thousands of years. Indeed, the Great Pyramid of Giza (Khufu Pyramid) was one of the Seven Wonders of the Ancient World. It is now accepted that ancient Egyptian engineers exploited a former channel of the Nile to transport building materials and provisions to the Giza plateau. However, there is a paucity of environmental evidence regarding when, where, and how these ancient landscapes evolved. New palaeoecological analyses have helped to reconstruct an 8,000-year fluvial history of the Nile in this area, showing that the former waterscapes and higher river levels around 4,500 years ago facilitated the construction of the Giza Pyramid Complex.

Continue reading “Nile waterscapes facilitated the construction of the Giza pyramids during the 3rd millennium BCE” | >