Latest news with #ScienceTokyo
Yahoo
30-06-2025
- Science
- Yahoo
Five-dimensional physics solves decades-old mystery of mercury fission
An international team of researchers, including scientists from Science Tokyo, has developed a five-dimensional Langevin model that accurately reproduces the complex fission fragment distributions and kinetic energies of medium-mass mercury isotopes like 180Hg and 190Hg. Unlike previous models that struggled to explain mercury's asymmetric fission, this approach captures the unusual double-humped mass distribution seen in mercury-180, revealing how nuclear shell effects continue to shape fission dynamics even at higher excitation energies than previously assumed. By demonstrating that these structural effects persist beyond heavy elements like uranium and plutonium, the findings enhance the understanding of nuclear fission processes and could improve predictive models for unexplored isotopes across the nuclear chart. Aiming to uncover the reasons behind mercury's unusual fission behavior, Associate Professor Chikako Ishizuka and her international team at the Institute of Zero-Carbon Energy, Science Tokyo, developed a five-dimensional Langevin model. Published online in Physical Review C on May 20, 2025, their study offers precise predictions of fragment distributions and total kinetic energy, earning recognition as an Editor's Suggestion by the journal. Unlike the well-studied fission of heavy elements such as uranium and plutonium, the way lighter nuclei like mercury split remains poorly understood. Experiments have revealed that mercury-180 undergoes an unusual asymmetric fission, producing fragments of very different sizes. These surprising results challenge current theories and highlight the need to understand how nuclear structure influences fission in elements with atomic numbers below 82. The Langevin model tracks the changing shape of the nucleus in real time, from its initial equilibrium state to the point of scission when it splits into smaller fragments. Developing consistent models for these lighter elements is crucial, as they often behave very differently from well-studied heavy isotopes. In their study, the team focused on two mercury isotopes: 180Hg, created by colliding 36Ar with 144Sm, and 190Hg, formed from 36Ar and 154Sm. They calculated how the fission fragments split and their total kinetic energies. One major improvement in the model was the introduction of a soft wall at the edges of the deformation space, allowing it to more accurately simulate how the nucleus changes shape during fission. The researchers also included the way shell effects evolve with rising excitation energy, a factor often oversimplified in earlier models. Additionally, the simulation closely matched experimental results for both the fragment mass distributions and total kinetic energy. For 180Hg, it successfully recreated the unusual double-peaked mass pattern observed in experiments. The study also revealed that shell effects remain important even at higher excitation energies of 40–50 MeV, contradicting earlier assumptions that they disappear. The researchers also included multichance fission, where the nucleus releases neutrons before splitting. They found this has little impact on fragment masses at low energies but strongly affects the total kinetic energy, making TKE a useful way to study multichance fission. According to Ishizuka, these findings offer valuable new insights into the fission process, deepening our fundamental understanding of nuclear behavior, and they confirm that the 5D Langevin approach is a reliable and effective tool for accurately predicting key fission observables.
Yahoo
25-06-2025
- Science
- Yahoo
Researchers discover game-changing method to unlock clean water for billions of people: 'Can also be used to distill groundwater'
What if a hunk of hot metal could unlock clean water for billions of people? A team of researchers in Japan has developed a groundbreaking new method — and it's powered by something as abundant as sunlight. A team led by associate professor Masatoshi Kondo at the Institute of Science Tokyo, has developed a method to use liquid tin to desalinate seawater and recover valuable metals simultaneously, utilizing solar heat as the primary energy source. Unlike traditional desalination, which consumes significant amounts of electricity and generates toxic brine, this method is low-waste, low-energy, and high-reward. "Unlike conventional methods, large consumption of electricity is not necessary, enabling the development of a sustainable process," said Dr. Kondo. Over four billion people experience water scarcity each year, and the demand for clean drinking water continues to increase. Traditional desalination can help — but it's costly, energy-hungry, and generates an estimated over five billion cubic feet of brine daily. That's enough to fill around 50,000 Olympic-sized swimming pools, often dumped back into oceans where it harms marine life. This is where Dr. Kondo and his research team come in. Co-authored by doctoral student Toranosuke Horikawa, then-bachelor student Mahiro Masuda, and assistant professor Minho Oh from Science Tokyo, their study aims not only to find a simple solution to desalination but also to transform the brine from an environmental issue into a resource. Kondo's team flips the script by using the brine as a resource instead of waste. Here's how it works. Brine is sprayed onto molten tin. The heated tin evaporates the water, leaving behind a mix of useful metals, including magnesium, calcium, and potassium. As the tin cools, it releases these metals for recovery. Meanwhile, the steam condenses into distilled fresh water. This isn't just a lab curiosity — it's a game-changer for public health, especially in areas hardest hit by drought, contamination, or poor infrastructure. Researchers can also adapt the process to treat polluted groundwater, including arsenic-contaminated sources that pose a threat to millions worldwide. And because it relies on heat — ideally from solar power — it could bring clean water access to off-grid or resource-limited communities. "The proposed technology … can also be used to distill groundwater polluted with arsenic without consuming large amounts of energy or producing waste," Dr. Kondo added. Though still in the research phase, this discovery could mark a major leap forward in sustainable water treatment. It tackles two issues at once — clean water access and resource recovery — while keeping environmental impact low. If scaled successfully, it could reduce costs, decrease pollution, and help stabilize ecosystems affected by over-extraction and drought. Join our free newsletter for weekly updates on the latest innovations improving our lives and shaping our future, and don't miss this cool list of easy ways to help yourself while helping the planet.
