Liquids evaporating into vapour is a daily occurrence, and yet the time it takes a liquid droplet to completely evaporate has remained a mysteryResearchers at the University of Warwick have analysed this process down to the nano-scale to reveal fascinating new physics in the vapour's flowThe new theory, which accurately predicts the lifetime of droplets can now be exploited for engineering designThe lifespan of a liquid droplet which is transforming into vapour can now be predicted thanks to a theory developed at the University of Warwick.The new understanding can now be exploited in a myriad of natural and industrial settings where the lifetime of liquid drops governs a process' behaviour and efficiency.Water evaporating into vapour forms part of our daily existence, creating plumes emanating from a boiling kettle and bulging clouds as part of the earth's water cycle.
They shape-shift into their surroundings as puddles and streams, largely beyond human control.Lauren Zarzar is trying to make more obedient liquids.Zarzar, a materials scientist at Pennsylvania State University, designs liquids that she can tame—fluids that move or change shape on command.When she changes the temperature of the droplet’s surroundings, she can make the droplet turn inside out.They’re not sure what they want to do with the droplets, but Zarzar imagines that you could use them to trigger chemical reactions: Place a catalyst inside some droplets, dump them into a container of reactants, and when you want the reaction to begin just flip the droplets inside out.Or, she thinks they could be fashioned into liquid lenses for a microscopic camera that change their focus by morphing in real time.
BUFFALO, N.Y. -- University at Buffalo physicists are using innovative tools to study the properties of a bizarre class of molecules that may play a role in disease: proteins that cluster together to form spherical droplets inside human cells.Published on Feb. 19 in the journal Biomolecules as a featured article, the study finds that certain protein droplets harden, becoming gelatinous in crowded environments (such as test tubes where lots of other molecules are present, mimicking the congested conditions inside living cells)."Prior research has focused on the structure of the proteins themselves, but our work shows that environmental factors are equally important.We see that external conditions can alter the internal state of the droplets, which may affect their function in human cells."Recent studies point to potential roles for these droplets in such diverse functions as gene expression, stress response and immune system function.The new paper investigates a droplet-forming protein called fused in sarcoma (FUS).
The creation of membranes is of enormous importance in biology, but also in many chemical applications developed by humans.These membranes are shaped spontaneously when soap-like molecules in water join together.Researchers at Eindhoven University of Technology now have a clear picture of the entire process.The results are published in Nature Chemistry.These molecules have a head that bonds with water, but a tail that turns away from water.You can imagine that a group of such molecules in water, preferably puts the tails together, and sticks the heads out, towards the water.
Academics from Northumbria University are to continue their ground-breaking research into the behaviour of liquids, leading a new project to investigate how to control the way liquids form into droplets.The team from Northumbria's Smart Materials and Surfaces Laboratory will work in partnership with Nottingham Trent University on the three-year study, which has received £700,000 funding from the Engineering and Physical Sciences Research Council.To initiate a process called 'Dynamic Dewetting,' the researchers will use electrical voltages to force liquids placed on certain types of surface to form specific shapes, such as triangles and squares, and then retract.This enables them to form the final shapes that you want them to appear in.Thanks to their work, the techniques they discovered have been implemented into software for use throughout the printing industry.Professor Glen McHale is the principal investigator on the study.
Hold a cold drink on a hot day, and watch as small droplets form on the glass, eventually coalescing into a layer of moisture (and prompting you to reach for a coaster).This basic physical process, condensation, is what refrigerators and air conditioners use to remove heat from vapor by turning it into a liquid.Just like the cold glass, the surfaces of metal condensers form thin layers of moisture as they work.The liquid layer acts as a thermally resistant barrier between the warm vapor and the cold condenser surface, decreasing the condenser's heat transfer efficiency.Materials scientists at Colorado State University have spent time thinking about this problem.Their new strategy could potentially increase the efficiency of condensers, used in many domestic and industrial products.
Tokyo, Japan - Researchers from Tokyo Metropolitan University have discovered a new way of controlling the drying patterns formed by re-crystallizing salt.Anyone who has visited the beach this summer would have felt large chunks of salt form on their skin after a splash in the sea.The drying of salt solution is actually a very complex phenomenon involving the interplay of many variables, including concentration and density profiles, heat transfer, as well as a wide range of environmental factors such as temperature and humidity.Understanding and controlling the mechanisms behind re-crystallization is crucial to understanding drying-related industrial processes like the adhesion of printer ink, the manufacture of devices based on thin films, as well as phenomena like salt damage in brick and the dissolving of pharmaceuticals in the human body.Drying droplets of solid-laden solution often leaves large, uneven chunks deposited at the edge.This so-called coffee ring effect is a result of different rates of evaporation on the top and at the edge of droplets, leading to a flow inside the droplet which drives an accumulation of solid particles at the edge.
-- When spraying paint or coatings onto a surface, or fertilizers or pesticides onto crops, the size of the droplets makes a big difference.Bigger drops will drift less in the wind, allowing them to strike their intended targets more accurately, but smaller droplets are more likely to stick when they land instead of bouncing off.Now, a team of MIT researchers has found a way to balance those properties and get the best of both -- sprays that don't drift too far but provide tiny droplets to stick to the surface.The team accomplished this in a surprisingly simple way, by placing a fine mesh in between the spray and the intended target to break up droplets into ones that are only one-thousandth as big.The findings are reported today in the journal Physical Review Fluids, in a paper by MIT associate professor of mechanical engineering Kripa Varanasi, former postdoc Dan Soto, graduate student Henri-Louis Girard, and three others at MIT and at CNRS in Paris.The runoff of pesticides that miss their target and fall on the ground can be a significant cause of pollution and a waste of the expensive chemicals.
DURHAM, N.C. -- Engineers at Duke University have developed a way to manipulate, split and mix droplets of biological fluids by having them surf on acoustic waves in oil.The technology could form the basis of a small-scale, programmable, rewritable biomedical chip that is completely reusable for disparate purposes from on-site diagnostics to laboratory-based research.The study appears on July 26 in the journal Nature Communications.While ubiquitous in the modern biomedical research and pharmaceutical industries, these systems are bulky, expensive and do not handle small volumes of liquids well.Lab-on-a-chip systems have been able to fill this space to some extent, but most are hindered by one major drawback -- surface absorption."There are a lot of protein-laden fluids and certain reagents that tend to stick to the chips that are handling them," said Tony Jun Huang, the William Bevan Professor of Mechanical Engineering and Materials Science at Duke.
Tokyo, Japan - Researchers from Tokyo Metropolitan University have observed the formation of holes that move by themselves in droplets of ionic liquids (IL) sitting inside water-ethanol mixtures.This curious, complex phenomenon is driven by an interplay between how ionic liquids dissolve, and how the boundary around the droplet fluctuates.Self-driven motion is a key feature of active matter, materials that use ambient energy to self-propel, with potential applications to drug delivery and nano-machine propulsion.How well they mix depends on the environment the mixture is in, like temperature and pressure.However, dissolution takes a complex turn when we add another component.Ionic liquids are liquids composed entirely of ions in ambient conditions; properties like their resistance to drying and ability to dissolve otherwise difficult materials have led to their being referred to as a "solvent of the future" [1], with a focus on how they might play a role in industrial processes e.g.
An international team of researchers, affiliated with UNIST has discovered a novel method for the synthesis of ultrathin semiconductors.In the study, the research team has successfully fabricated MoS2 nanoribbons via vapour-liquid-solid (VLS) growth mechanism, a type of chemical vapour deposition (CVD) process."Synthesis of vertically elongated structure via VLS growth mechanism.""The range of structures that can be controllably synthesized by the current methods is still limited in terms of morphology, spatial selectivity, crystal orientation, layer number and chemical composition," the research team noted."Therefore, developing versatile growth methods is essential to the realization of highly integrated electronic and photonic devices based on these materials."The current CVD-based growth process relies on the inherent dynamics of the precursors to diffuse and self-organize on the substrate surface, which results in crystallites with characteristic triangular or hexagonal shapes," says Dr. Zhao.
We are used to solar panels which can harvest power from sunlight during the day.Yes, it sounds impossible, but it’s actually just been demonstrated by researchers at China’s Soochow University.The new type of solar panel incorporates a triboelectric nanogenerator (TENG), a means of converting mechanical energy, aka motion into electricity.“Solar cells have become one of the most widespread solutions in the crisis issues of the environment and energy,” Zhen Wen, an assistant professor in the Institute of Functional Nano and Soft Materials at Soochow, told Digital Trends.“However, the power generation from a solar cell is affected by various weather conditions — for example, rainy weather.The intermittent and unpredictable nature of solar energy is an inevitable challenge for its expansion as a reliable power supply system.
WASHINGTON -- In a new study, researchers showed that using sound waves to levitate droplets of water in midair can improve the detection of harmful heavy metal contaminants such as lead and mercury in water.Detecting small amounts of heavy metals in water is important because these contaminants are harmful to human health and the environment.The new technique could eventually lead to instruments that perform real-time, on-site contaminant monitoring, which could help prevent future lead contamination problems like the Flint, Michigan, water crisis or detect contaminated wastewater from industrial sites."Despite the large variety of water sensors that offer continual monitoring, detection of multiple heavy metals dissolved in water can only be performed by sending samples off for specialized laboratory analysis," said the research team leader Victor Contreras, from Instituto de Ciencias Físicas UNAM, Mexico.In The Optical Society (OSA) journal Optics Letters, the researchers detail their new approach, which uses a sensitive technique known as laser induced breakdown spectroscopy (LIBS) to analyze heavy metals present in levitating drops of water.The researchers showed that their new approach can reliably detect very low levels of the heavy metals like barium, cadmium and mercury with analysis times of just a few minutes.
Screens are all around us and are immensely useful in conveying information – but they can overwhelm us and take up more of our attention than we can afford.That’s why MIT Media Lab researcher Udayan Umapathi began work on a calm interface that had a closer connection to the physical elements around us – using water.Together with his colleagues – which include engineers and interaction designers – Umapathi created a project for his graduate thesis work called Programmable Droplets.Have a look in the clip below:This is made possible through a technique called electrowetting, which allows for manipulating dielectric materials like water with electric fields.Umapathi explained that he first worked out the physics for programming sand particles when he took Professor Neil Gernshenfeld’s class on the “Physics of Information Technology,” and that their discussions led to the idea that the derivations would apply to water as well.
OnePlus possibly teased the OnePlus 6’s water resistance on Twitter.If true, the OnePlus 6 would be the first OnePlus smartphone officially rated for water and dust resistance.OnePlus remains mum on launch details, though the OnePlus 6 could debut within the next two months.It took OnePlus four generations of smartphones, but the company might finally include some sort of water resistance for its upcoming flagship, the OnePlus 6.That is according to OnePlus’ recent tweet, which is a three-second video of raindrops hitting a surface.That surface could be the OnePlus 6’s display, but the company remains tight-lipped on details.
Whether it is gravity-defying phone chargers or human-floating tractor beams, we’re suckers for levitating technologies.A new Kickstarter campaign therefore hits our sweet spot with an “executive novelty” (read: a high-priced desk toy) that levitates water droplets entirely for your viewing pleasure.Called LeviZen, the retro-styled device itself is crafted out of high grade walnut wood and precision-machined aluminum with the necessary audio technology to float drops of liquid using high frequency sound waves not audible to regular ears.It also boasts some in-built LEDs to make sure the water droplets are properly illuminated so as to look their best.No, it doesn’t have any practical applications, but it certainly promises to be an attention-grabbing conversation starter.Unlike the majority of levitating gadgets we’ve written about in the past, LeviZen doesn’t use magnetic levitation to achieve its effect, due to the fact that this would not work with a liquid like water.
Forget everything you were taught in primary school.Not yet big enough for air resistance to have an influence, it’s this surface tension that determines the spherical shape of tiny raindrops.Air resistance starts to influence their shape, flattening the bottom of each droplet and morphing the sphere into a blob shaped like a hamburger bap.Following an upgrade to the Met Office’s 30-year-old rainfall radar network, we can now gain more real-time information from falling precipitation – rain, sleet, snow, hail and ice pellets – than ever before, including the size and shape of the droplets.The seven-year roll out of the new radar network across the UK was motivated by the need to replace an increasingly difficult to maintain radar network.Supported by a range of local suppliers as well as the Environment Agency, which co-funded the project, the UK’s rainfall radar network is now more resourceful than before.
MIT researchers have developed hardware that uses electric fields to move droplets of chemical or biological solutions around a surface, mixing them in ways that could be used to test thousands of reactions in parallel.The researchers view their system as an alternative to the microfluidic devices now commonly used in biological research, in which biological solutions are pumped through microscopic channels connected by mechanical valves."Traditional microfluidic systems use tubes, valves, and pumps," says Udayan Umapathi, a researcher at the MIT Media Lab, who led the development of the new system.I noticed this problem three years ago, when I was at a synthetic biology company where I built some of these microfluidic systems and mechanical machines that interact with them."Biology is moving toward more and more complex processes, and we need technologies to manipulate smaller- and smaller-volume droplets," Umapathi says.The system includes software that allows users to describe, at a high level of generality, the experiments they wish to conduct.
As it cools, it creates a crystal clear tadpole-like droplet that’s bulletproof on one end, but impossibly fragile on the other.We’ve known about these droplets for 400 years, but scientists have only recently figured out what makes them almost indestructible.In a video posted just a few weeks ago, SmarterEveryDay’s Destin Sandlin fired a .22 Magnum bullet with a full metal jacket at a Prince Rupert’s Drop, so-named after Germany’s Prince Rupert gifted five of the unusual glass objects to England’s King Charles II back in 1661.The baffling results of that experiment, with the bullet disintegrating as it collides with the thicker end of the glass teardrop, are no longer a mystery.Making a Prince Rupert’s Drop is easy, you just need to melt a glass with a high thermal expansion coefficient—glass that expands when heated—like soda-lime or leaded glass, and then drop a molten blob of it into a container of cold water, which immediately cools it down in a process known as quenching.As the drop quickly cools, its outer layer experiences a temperature drop faster than its interior, which results in extreme compressive forces on the outside, but strong tensile (pulling) stresses on the inside.
Thanks to the dirt beneath your feet, you just committed mass murder in your quest to taste the rain.For every raindrop that hits the ground, up to thousands of bacteria are catapulted into the air, trapped inside tiny beads of water.Some of these unwitting aeronauts fall right back to Earth, but other bacteria are swept skyward, potentially moving vast distances before finding a new home, according to Cullen Buie, a mechanical engineer at the Massachusetts Institute of Technology who has spent years studying the surprisingly beautiful physics of rainfall.It all started a few years back, when Buie and his colleagues used high-speed cameras to visualize raindrops striking a porous surface.They observed that when water droplets fall at speeds similar to those of a light rain, they trap tiny bubbles upon impact.“That’s the same process, only with CO2 bubbles bursting and releasing kinetic energy.”
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