Invigorating the idea of computers based on fluids instead of silicon, researchers at the National Institute of Standards and Technology (NIST) have shown how computational logic operations could be performed in a liquid medium by simulating the trapping of ions (charged atoms) in graphene (a sheet of carbon atoms) floating in saline solution. The scheme might also be used in applications such as water filtration, energy storage or sensor technology.
The idea of using a liquid medium for computing has been around for decades, and various approaches have been proposed. Among its potential advantages, this approach would require very little material and its soft components could conform to custom shapes in, for example, the human body.
NIST’s ion-based transistor and logic operations are simpler in concept than earlier proposals. The new simulations show that a special film immersed in liquid can act like a solid silicon-based semiconductor. For example, the material can act like a transistor, the switch that carries out digital logic operations in a computer. The film can be switched on and off by tuning voltage levels like those induced by salt concentrations in biological systems.
Scientists boost the accuracy of optical microscopes to image microdroplets in flight and apply the method to analyze the concentration of plastic nanoparticles.
Sneezes, rain clouds, and ink jet printers: They all produce or contain liquid droplets so tiny it would take several billion of them to fill a liter bottle.
Measuring the volume, motion and contents of microscopic droplets is important for studying how airborne viruses spread (including those that cause COVID-19), how clouds reflect sunlight to cool the Earth, how ink jet printers create finely detailed patterns, and even how a soda bottle fragments into nanoscale plastic particles that pollute the oceans.
By improving the calibration of a conventional optical microscope, researchers at the National Institute of Standards and Technology (NIST) have for the first time measured the volume of individual droplets smaller than 100 trillionths of a liter with an uncertainty of less than 1%. That is a tenfold improvement over previous measurements.
Can a mix of solids form a liquid? In a “deep eutectic system” (DES), yes. In these cases—which includes some mixtures of sugars, amino acids, and organic acids—compounds that are typically solid at room temperature lower each other’s melting points when combined in some ratios. As a result, they melt. Starting at the left, this picture shows two natural compounds, menthol and lauric acid. Combined in a certain molar fraction as they were heated and stirred, the compounds formed the eutectic liquid in the flask on the right. After the liquid is formed, it remains stable at room temperature. This is also what happens with honey, a naturally occurring DES that is a viscous liquid resulting from the mixture of various sugars. Project Des.Solve, funded by the European Research Council, aims to extend knowledge of these systems, focusing on their characterization and boosting application to fields including extraction, biocatalysis, green chemistry, and biomedical science. — Craig Bettenhausen
Submitted by Liane Meneses and Luísa Pereira/Project Des.Solve
A new mathematical model describes how highly concentrated antibody solutions separate into different phases, similar to an oil and water mixture. This separation can reduce the stability and shelf-life of some drugs that use monoclonal antibodies, including some used to treat autoimmune diseases and cancer. A team of scientists from Penn State and MedImmune, LLC (now AstraZeneca) investigated the thermodynamics and kinetics, the relationships between temperature, energy, and the rates of chemical reactions, of the phenomenon using an innovative method that allows for the rapid study of multiple samples at once. A paper describing their model appears July 22, 2019, in the journal Proceedings of the National Academy of Sciences.
Many drugs today are stored as solids and dissolved in IV bags for delivery to patients, but the pharmaceutical industry has been moving toward drugs that can be stored as liquids and given via a shot. Some of these drug solutions, like those used to treat autoimmune diseases and some cancers, contain high concentrations of monoclonal antibodies—proteins that attach to foreign substances in the body, like bacteria and viruses, flagging them for destruction by the patient’s immune system.
After many decades of astonishing developments, advances in semiconductor-based computing are beginning to slow as transistors reach their physical limits in size and speed. However, the requirements for computing continue to grow, especially in artificial intelligence, where neural networks often have several millions of parameters. One solution to this problem is reservoir computing, and a team of researchers led by Osaka University, with colleagues from the University of Tokyo and Hokkaido University, have developed a simple system based on electrochemical reactions in Faradic current that they believe will jump-start developments in this field.
Reservoir computing is a relatively recent idea in computing. Instead of traditional binary programs run on semiconductor chips, the reactions of a nonlinear dynamical system—the reservoir—are used to perform much of the calculation. Various nonlinear dynamical systems from quantum processes to optical laser components have been considered as reservoirs. In this study, the researchers looked at the ionic conductance of electrochemical solutions.
Inspired by healing wounds in skin, a new approach protects and heals surfaces using a fluid secretion process. In response to damage, dispersed liquid-storage droplets are controllably secreted. The stored liquid replenishes the surface and completes the repair of the polymer in seconds to hours.
The fluid secretion approach to repair the material has also been demonstrated in fibers and microbeads. This bioinspired approach could be extended to create highly desired adaptive, resilient materials with possible uses in heat transfer, humidity control, slippery surfaces, and fluid delivery.
A polymer that secretes stored liquid in response to damage has been designed and created to function as a self-healing material. While human-made material systems can trigger the release of stored contents, the ability to continuously self-adjust and monitor liquid supply in these compartments is a challenge. In contrast, biological systems manage complex protection and healing functions by having individual components work in concert to initiate and self-regulate a coordinated response. Inspired by biological wound-healing, this new process, developed by researchers at Harvard University, involves trapping and dispersing liquid-storage droplets within a reversibly crosslinked polymer gel network topped with a thin liquid overlayer. This novel approach allows storage of the liquid, yet is reconfigurable to induce finely controlled secretion in response to polymer damage.
Developed by researchers at the University of Texas, Austin, the new membrane-free semi-liquid battery, consisting of a liquid ferrocene electrolyte, a liquid cathode and a solid lithium anode, exhibited encouraging early results, encompassing many of the features desired in a state-of-the-art…
Animals have evolved all manner of adaptations to get the nutrients they need. For nectar-feeding bats, long snouts and tongues let them dip in and out of flowers while hovering in mid-air. To help the cause, their tongues are covered in tiny hairs that serve as miniature spoons to scoop and drag up the tasty sap.
Now engineers at MIT have found that, for bats and other hairy-tongued nectar feeders, the key to drinking efficiently lies in a delicate balance between the spacing of hairs on the tongue, the thickness of the fluid, and the “speed of retraction,” or how fast an animal darts its tongue back to slurp up the nectar. When all three of these parameters are in balance, a good amount of nectar reaches the animal’s mouth instead of dribbling away.
As it happens, the same goes for other hairy-tongued nectar feeders, such as honeybees and honey possums, which the researchers found also exhibit optimal “viscous entrainment,” which refers to the amount of fluid that hairy surfaces can drag up from a bath.
“There are lots of different drinking techniques for animals, and what we think is normal when we drink is really a singular way of drinking,” says Pierre-Thomas Brun, a former instructor in MIT’s Department of Mathematics. “We hope that our theory explains what are the main trending mechanisms of this hairy drinking method, and we believe we have rationalized this peculiar drinking technique.”
A small team of researchers with the Technical University of Denmark and Drexel University in the U.S. has found that it is possible to cause a liquid to crack under the right conditions. In their paper published in the journal Physical Review Letters, the team describes their experiments, what they learned and outline ways in which their findings may be suitable for use in industrial applications in the future.
A lot of study has been done regarding cracksinsolid materials to learn what causes them, how to prevent them, etc. Doing so has helped to create materials that better suit our purposes and which are, in some cases, safer for us to use, e.g. for airplane components. But up till now, little work has been done to study cracks in liquids, in part because it would seem logical to assume that they don’t exist. But as the researchers with this new effort found, they not only do exist, but take on many of the same properties as cracks that occur and propagate through solid materials.
We normally consider liquid water as disordered with the molecules rearranging on a short time scale around some average structure. Now, however, scientists at Stockholm University have discovered two phases of the liquid with large differences in structure and density. The results are based on experimental studies using X-rays, which are now published in Proceedings of the National Academy of Science(US).
Most of us know that water is essential for our existence on planet Earth. It is less well-known that water has many strange or anomalous properties and behaves very differently from all other liquids. Some examples are the melting point, the density, the heat capacity, and all-in-all there are more than 70 properties of water that differ from most liquids. These anomalous properties of water are a prerequisite for life as we know it.
“The new remarkable property is that we find that water can exist as two different liquids at low temperatures where ice crystallization is slow”, says Anders Nilsson, professor in Chemical Physics at Stockholm University. The breakthrough in the understanding of water has been possible through a combination of studies using X-rays at Argonne National Laboratory near Chicago, where the two different structures were evidenced and at the large X-ray laboratory DESY in Hamburg where the dynamics could be investigated and demonstrated that the two phases indeed both were liquid phases. Water can thus exist as two different liquids.
Supercooled water is really two liquids in one. That’s the conclusion reached by a research team at the U.S. Department of Energy’s Pacific Northwest National Laboratory after making the first-ever measurements of liquid water at temperatures much colder than its typical freezing point.
The finding, published today in the journal Science, provides long-sought experimental data to explain some of the bizarre behavior water exhibits at extremely cold temperatures found in outer space and at the far reaches of Earth’s own atmosphere. Until now, liquid water at the most extreme possible temperatures has been the subject of competing theories and conjecture. Some scientists have asked whether it is even possible for water to truly exist as a liquid at temperatures as low as -117.7 F (190 K) or whether the odd behavior is just water rearranging on its inevitable path to a solid.
The argument matters because understanding water, which covers 71 percent of the Earth’s surface, is critical to understanding how it regulates our environment, our bodies and life itself.
From common soot to precious diamonds, carbon is familiar in many guises, but there have been little more than glimpses of carbon in the liquid form. Researchers at the FERMI Free Electron Laser (FEL) source have now not only generated a liquid carbon sample, but have characterized its structure, tracking the ultrafast rearrangements of electron bonding and atomic coordinates that take place as their carbon samples melt. “As far as I know, that is the fastest structural transition in condensed matter,” says Emiliano Principi, principal investigator on the project.
The work fills in some of the gaps in the element’s phase diagram—a plot of its phases at different temperatures and pressures. Despite the ubiquity of carbon and the interest it garners in so many facets of science—from sensorsandsolar cellstoquantum computingandspace rocket protection systems—knowledge of its phase diagram remains patchy. Typically, as soon as solid carbon can’t take the heat, it sublimates to gas. For other materials, researchers can enroll high-pressure cells to prevent the sample expanding straight into a gas at high temperatures, but these are usually diamond, precisely the element the conditions are designed to melt.
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