Lifeboat Foundation

Study is first demonstration of a fully 3D-printed thruster using pure ion emission for propulsion.

A 3D-printed thruster that emits a stream of pure ions could be a low-cost, extremely efficient propulsion source for miniature satellites.

The nanosatellite thruster created by MIT researchers is the first of its kind to be entirely additively manufactured, using a combination of 3D printing and hydrothermal growth of zinc oxide nanowires. It is also the first thruster of this type to produce pure ions from the ionic liquids used to generate propulsion.

Metallurgists have all kinds of ways to make a chunk of metal harder. They can bend it, twist it, run it between two rollers or pound it with a hammer. These methods work by breaking up the metal’s grain structure—the microscopic crystalline domains that form a bulk piece of metal. Smaller grains make for harder metals.

Now, a group of Brown University researchers has found a way to customize metallic grain structures from the bottom up. In a paper published in the journal Chem, the researchers show a method for smashing individual metal nanoclusters together to form solid macro-scale hunks of solid metal. Mechanical testing of the metals manufactured using the technique showed that they were up to four times harder than naturally occurring metal structures.

“Hammering and other hardening methods are all top-down ways of altering grain structure, and it’s very hard to control the grain size you end up with,” said Ou Chen, an assistant professor of chemistry at Brown and corresponding author of the new research. “What we’ve done is create nanoparticle building blocks that fuse together when you squeeze them. This way we can have uniform grain sizes that can be precisely tuned for enhanced properties.”

When sheets of two-dimensional nanomaterials like graphene are stacked on top of each other, tiny gaps form between the sheets that have a wide variety of potential uses. In research published in the journal Nature Communications, a team of Brown University researchers has found a way to orient those gaps, called nanochannels, in a way that makes them more useful for filtering water and other liquids of nanoscale contaminants.

“In the last decade, a whole field has sprung up to study these spaces that form between 2-D nanomaterials,” said Robert Hurt, a professor in Brown’s School of Engineering and coauthor of the research. “You can grow things in there, you can store things in there, and there’s this emerging field of nanofluidics where you’re using those channels to filter out some molecules while letting others go through.”

There’s a problem, however, with using these nanochannels for filtration, and it has to do with the way those channels are oriented. Like a notebook made from stacked sheets of paper, graphene stacks are thin in the vertical direction compared to their horizontal length and width. That means that the channels between the sheets are likewise oriented horizontally. That’s not ideal for filtration, because liquid has to travel a relatively long way to get from one end of a channel to the other. It would be better if the channels were perpendicular to the orientation of the sheets. In that case, liquid would only need to traverse the relatively thin vertical height of the stack rather than the much longer length and width.

The SonoMask displayed an ability to neutralize the novel coronavirus at an effectiveness of 99.34% within trials performed by the ATCCR Testing laboratory in China, Ramat Gan-based Israeli fabric maker and developer Sonovia announced on Saturday. Sonovia’s reusable anti-viral masks are coated in zinc oxide nanoparticles that destroy bacteria, fungi and viruses, which it says can help stop the spread of the coronavirus. Results from the most recent round of testing showed that the mask has the ability to neutralize fallen traces of SARS-COV-2 within 30 minutes after making contact with the fabric. The SonoMask was also proven to maintain its protective properties throughout 55 wash cycles.” Following this outstanding result – the product of several months of dedicated anti-viral sonochemistry formulation – we can now assure the public that our SonoMask is working continuously, permanently and rapidly to neutralize the spread of COVID-19,” said Sonovia CEO Joshua Hershcovici. “We are proud of our latest accomplishment that will help people feel safe and protect their loved ones, all the while remaining the most ecologically sound option upon the PPE market.” Sonovia also participated in trials with Adler Plastic in Italy earlier this year, working toward creating a solution for carpets and other types of fabrics. The company boasted a 99.999% efficiency rate against bacteria during the pilot testing round. Furthermore, the Israeli fabric maker has attracted the cooperation of top brands such as Gucci, Chanel and Adidas, working on the Fashion for Good Plug and Play accelerator project – and earning a $250000 investment for their innovation.” We see our breakthrough technology transforming our everyday life, implemented in all textiles surrounding us: from the clothes we wear, to the textiles in our home, the textiles in our public spaces, in public transportation and of course as a protective measure in the workplaces & medical institutes – in a manner that ensures safer surroundings during these unusual times,” said Sonovia’s Chief Technology Officer Liat Goldhammer.

Advanced optoelectronics require materials with newly engineered characteristics. Examples include a class of materials named metal-halide perovskites that have tremendous significance to form perovskite solar cells with photovoltaic efficiencies. Recent advances have also applied perovskite nanocrystals in light-emitting devices. The unusually efficient light emission of cesium lead-halide perovskite may be due to a unique excitonic fine structure made of three bright triplet states that minimally interact with a proximal dark singlet state. Excitons are electronic excitations responsible for the emissive properties of nanostructured semiconductors, where the lowest-energy excitonic state is expected to be long lived and hence poorly emitting (or ‘dark’).

In a new report now published in Science Advances, Albert Liu and a team of scientists in physics and chemistry at the University of Michigan, U.S., and Campinas State University, Brazil, used multidimensional coherent spectroscopy at cryogenic (ultra-cold) temperatures to study the fine structure without isolating the cube-shaped single nanocrystals. The work revealed coherences (wave properties relative to space and time) involving the triplet states of a cesium lead-iodide (CsPbI₃) nanocrystal ensemble. Based on the measurements of triplet and inter-triplet coherences, the team obtained a unique exciton fine structure level ordering composed of a dark state, energetically positioned within the bright triplet manifold.

Exotic and vibrant colors naturally occur in nature because of pigmentations. But nature is also capable of displaying a whole spectrum of eye-catching colors through building nano-scale surface structures. Creatures with intricate physical aesthetics, like a peacock’s feathers or the rich patterns on a butterfly’s wings, achieve this kind of high color resolution due to the small-scale arrays of distinctly shaped objects on their surfaces. This naturally occurring color structure was exploited by a team of researchers from the Technical University of Denmark (DTU). They developed a laser printing technique that doesn’t require ink.

Laser printing without ink

Continue reading “This Laser Printer Can Produce Vibrant Colors Without Ink” »

A team of biophysicists from the University of Massachusetts Amherst and Penn State College of Medicine set out to tackle the long-standing question about the nature of force generation by myosin, the molecular motor responsible for muscle contraction and many other cellular processes. The key question they addressed—one of the most controversial topics in the field—was: how does myosin convert chemical energy, in the form of ATP, into mechanical work?

The answer revealed new details into how myosin, the engine of muscle and related motor proteins, transduces energy.

In the end, their unprecedented research, meticulously repeated with different controls and double-checked, supported their hypothesis that the mechanical events of a molecular motor precede—rather than follow—the biochemical events, directly challenging the long-held view that biochemical events gate the force-generating event. The work, published in the Journal of Biological Chemistry, was selected as an Editor’s Pick for “providing an exceptional contribution to the field.”

Researchers develop the first nanomaterial that demonstrates “photon avalanching;” finding could lead to new applications in sensing, imaging, and light detection.

Researchers at Columbia Engineering report today that they have developed the first nanomaterial that demonstrates “photon avalanching,” a process that is unrivaled in its combination of extreme nonlinear optical behavior and efficiency. The realization of photon avalanching in nanoparticle form opens up a host of sought-after applications, from real-time super-resolution optical microscopy, precise temperature and environmental sensing, and infrared light detection, to optical analog-to-digital conversion and quantum sensing.

“Nobody has seen avalanching behavior like this in nanomaterials before,” said James Schuck, associate professor of mechanical engineering, who led the study published today (January 132021) by Nature. “We studied these new nanoparticles at the single-nanoparticle level, allowing us to prove that avalanching behavior can occur in nanomaterials. This exquisite sensitivity could be incredibly transformative. For instance, imagine if we could sense changes in our chemical surroundings, like variations in or the actual presence of molecular species. We might even be able to detect coronavirus and other diseases.”

Researchers at Columbia Engineering report today that they have developed the first nanomaterial that demonstrates “photon avalanching,” a process that is unrivaled in its combination of extreme nonlinear optical behavior and efficiency. The realization of photon avalanching in nanoparticle form opens up a host of sought-after applications, from real-time super-resolution optical microscopy, precise temperature and environmental sensing, and infrared light detection, to optical analog-to-digital conversion and quantum sensing.

“Nobody has seen avalanching behavior like this in nanomaterials before,” said James Schuck, associate professor of mechanical engineering, who led the study published today by Nature. “We studied these new nanoparticles at the single-nanoparticle level, allowing us to prove that avalanching behavior can occur in nanomaterials. This exquisite sensitivity could be incredibly transformative. For instance, imagine if we could sense changes in our chemical surroundings, like variations in or the actual presence of molecular species. We might even be able to detect coronavirus and other diseases.”

Avalanching processes—where a cascade of events is triggered by series of small perturbations—are found in a wide range of phenomena beyond snow slides, including the popping of champagne bubbles, nuclear explosions, lasing, neuronal networking, and even financial crises. Avalanching is an extreme example of a nonlinear process, in which a change in input or excitation leads to a disproportionate—often disproportionately large—change in output signal. Large volumes of material are usually required for the efficient generation of nonlinear optical signals, and this had also been the case for photon avalanching, until now.