Showing posts with label nano. Show all posts
Showing posts with label nano. Show all posts

Monday, July 26, 2021

Meta-Materials Mega-Thread

The phrase "metallic-organic framework" (MOF) has been appearing in headlines with more frequency, seemingly out of nowhere. Then again, when the material science revolution is fully underway, we will also wonder where the heck it came from. 

MOFs fall into the same general category as meta-materials, related to nano-this and graphene-that. These articles are a reminder that we're in for a whole new world. Kind of like what plastic did for the post-war world we live in today, or the synthetic chemical revolution of the late 1800's that gave our world "colors". 

Image credit: Metal Organic Framework by Mike Gipple at NETL

Programmable synthetic materials
Aug 2020, phys.org
In the future, MOFs could form the basis of programmable chemical molecules: for instance, an MOF could be programmed to introduce an active pharmaceutical ingredient into the body to target infected cells and then break down the active ingredient into harmless substances once it is no longer needed. Or MOFs could be programmed to release different drugs at different times.

via University of California Berkeley: Sequencing of metals in multivariate metal-organic frameworks, Science (2020). DOI: 10.1126/science.aaz4304 
Breakthrough technology purifies water using the power of sunlight
Aug 2020, phys.org
Metal-organic frameworks are a class of compounds consisting of metal ions that form a crystalline material with the largest surface area of any material known. In fact, MOFs are so porous that they can fit the entire surface of a football field in a teaspoon.

via Monash University: A sunlight-responsive metal–organic framework system for sustainable water desalination, Nature Sustainability (2020). DOI: 10.1038/s41893-020-0590-x
Study shows promising material can store solar energy for months or years
Dec 2020, phys.org
In tests, the researchers exposed the material to UV light, which causes the azobenzene molecules to change shape to a strained configuration inside the MOF pores. This process stores the energy in a similar way to the potential energy of a bent spring. Importantly, the narrow MOF pores trap the azobenzene molecules in their strained shape, meaning that the potential energy can be stored for long periods of time at room temperature.

The energy is released again when external heat is applied as a trigger to 'switch' its state, and this release can be very quick—a bit like a spring snapping back straight. This provides a heat boost which could be used to warm other materials of devices.

Further tests showed the material was able to store the energy for at least four months. This is an exciting aspect of the discovery as many light-responsive materials switch back within hours or a few days. The long duration of the stored energy opens up possibilities for cross-seasonal storage.

via by Lancaster University: Kieran Griffiths et al, Long-Term Solar Energy Storage under Ambient Conditions in a MOF-Based Solid–Solid Phase-Change Material, Chemistry of Materials (2020). DOI: 10.1021/acs.chemmater.0c02708
Physicists create tunable superconductivity in twisted graphene 'nanosandwich'
Feb 2021, phys.org

Come on with that name though.

via Massachusetts Institute of Technology: Tunable strongly coupled superconductivity in magic-angle twisted trilayer graphene, Nature (2021). DOI: 10.1038/s41586-021-03192-0

Flash graphene rocks strategy for plastic waste
Oct 2020, phys.org
It's called flashing -- expose plastic waste to eight seconds of high-intensity alternating current, followed by the DC jolt. You'll get turbostratic graphene. Yes, graphene from garbage. $125 of electricity turns a ton of plastic into a ton of graphene.
via Rice University: Wala A. Algozeeb et al, Flash Graphene from Plastic Waste, ACS Nano (2020). DOI: 10.1021/acsnano.0c06328
Researchers use origami to solve space travel challenge
Dec 2020, phys.org

Origami bellow-bag fuel storage containers.

via Washington State University: Kjell Westra et al, Compliant Polymer Origami Bellows in Cryogenics, Cryogenics (2020). DOI: 10.1016/j.cryogenics.2020.103226

DNA origami enables fabricating superconducting nanowires
Jan 2021, phys.org
 
via the American Institute of Physics: "DNA origami-based superconducting nanowires" AIP Advances, aip.scitation.org/doi/10.1063/5.0029781

Researchers turn coal powder into graphite in microwave oven
Jan 2021, phys.org
Using copper foil, glass containers and a conventional household microwave oven, University of Wyoming researchers have demonstrated that pulverized coal powder can be converted into higher-value nano-graphite.

"By cutting the copper foil into a fork shape, the sparks were induced by the microwave radiation, generating an extremely high temperature of more than 1,800 degrees Fahrenheit within a few seconds," says Masi, lead author of the paper. "This is why you shouldn't place a metal fork inside a microwave oven."

via University of Wyoming: Christoffer A. Masi et al, Converting raw coal powder into polycrystalline nano-graphite by metal-assisted microwave treatment. Nano-Structures & Nano-Objects Volume 25, 2021, 100660, ISSN 2352-507X, doi.org/10.1016/j.nanoso.2020.100660
'Magnetic graphene' forms a new kind of magnetism
Feb 2021, phys.org

via University of Cambridge: Matthew J. Coak et al. 'Emergent Magnetic Phases in Pressure-Tuned van der Waals Antiferromagnet FePS3.' Physical Review X (2021). DOI: 10.1103/PhysRevX.11.011024

A new way to make wood transparent, stronger and lighter than glass
Feb 2021, phys.org
The conventional method for making wood transparent involves using chemicals to remove the lignin—a process that takes a long time, produces a lot of liquid waste and results in weaker wood. In this new effort, the researchers have found a way to make wood transparent without having to remove the lignin.

The process involved changing the lignin rather than removing it. The researchers removed lignin molecules that are involved in producing wood color. First, they applied hydrogen peroxide to the wood surface and then exposed the treated wood to UV light (or natural sunlight). The wood was then soaked in ethanol to further clean it. Next, they filled in the pores with clear epoxy to make the wood smooth.

via University of Maryland: Qinqin Xia et al. Solar-assisted fabrication of large-scale, patternable transparent wood, Science Advances (2021). DOI: 10.1126/sciadv.abd7342
Japan developing wooden satellites to cut space junk
Dec 2020, BBC News

Monday, July 5, 2021

On Engineering Artificial Eyeballs

Enhanced vision -- seeing the invisible, zooming-in past the limits of microscopy, making artificial eyeballs from scratch to give sight to the blind -- nothing says welcome to the future like advances in vision technology. 

Image credit: Sorry I can't find the source for this, but you can call it face-rec camo-tech. It makes you invisible. 

New method could democratize deep learning-enhanced microscopy
Mar 2021, phys.org
Deep learning is a potential tool for scientists to glean more detail from low-resolution images in microscopy, but it's often difficult to gather enough baseline data to train computers in the process. Now, a new method developed by scientists at the Salk Institute could make the technology more accessible—by taking high-resolution images, and artificially degrading them.

The new tool, which the researchers call a "crappifier," could make it significantly easier for scientists to get detailed images of cells or cellular structures that have previously been difficult to observe because they require low-light conditions, such as mitochondria, which can divide when stressed by the lasers used to illuminate them. 
Yes, the crappifier. If you have any idea how neural network machine learning works, you will immediately get why this is some sneaky shit.

They take good microphotographs (example: Nikon Small World Gallery) and intentionally make them crappy and hard to see. They degrade the photo artificially, but then train the network backwards to learn how to make a good photo out of a bad one. Once it's trained, they start giving it "naturally" bad photos of things we can't get good pictures of with current microscopic technology, and let it apply what it learned about bad photos. 

via Salk Institute: Deep learning-based point-scanning super-resolution imaging, Nature Methods (2021). DOI: 10.1038/s41592-021-01080-z

Smartphone camera used to diagnose viral infections
Dec 2020, phys.org

Full circle, we will soon be tossing coffee grinds on the table to predict the future. Here's an exapmle of how we can now see things we didn't even know we were looking for, like how the bubbles in your body-fluid broth have written in them your viral exposome. 
Body fluid samples are placed into a channel on the catalytic microchip device, which is then doused with a small amount of hydrogen peroxide. The resulting reaction leads to the formation of bubbles. The bubbles develop in unique patterns based in part on viruses in the fluid sample. The user points their smartphone camera at the bubbling sample and launches the deep-learning algorithm that has already been trained to identify the patterns and thereby recognize the presence of viruses.

Mohamed S. Draz et al. Virus detection using nanoparticles and deep neural network–enabled smartphone system, Science Advances (2020). DOI: 10.1126/sciadv.abd5354
Zoom hack reveals text contents by viewing shoulder movement
Nov 2020, phys.org

Jesus make it stop:
"They focused on the movement of their shoulders and arms to extrapolate the actions of their fingers as they typed."

"In a controlled setting, with specific chairs, keyboards and webcam, Jadiwala said he achieved an accuracy rate of 75 percent. However, in uncontrolled environments, accuracy dropped to only one out of every five words being correctly identified."

via the University of Texas: Zoom on the Keystrokes: Exploiting Video Calls for Keystroke Inference Attacks, Murtuza Jadiwala et al. arXiv:2010.12078 [cs.CR] arxiv.org/abs/2010.12078

Discovery makes the invisible visible
Jan 2021, phys.org

The nano-revolution comes to phase contrast microscopy. Sub-surface Nanoaperture Arrays.

via La Trobe Institute for Molecular Science: Eugeniu Balaur et al. Plasmon-induced enhancement of ptychographic phase microscopy via sub-surface nanoaperture arrays, Nature Photonics (2021). DOI: 10.1038/s41566-020-00752-0

Mantis shrimp inspires new breed of light sensors
Mar 2021, phys.org

The mantis shrimp strikes again, patron saint of all superhuman vision technology. Hyperspectral. 

via North Carolina State University: "Mantis shrimp-inspired organic photodetector for simultaneous hyperspectral and polarimetric imaging" Science Advances (2021).


For those artificial retinas you've been waiting for:
Color-sensitive inkjet-printed pixelated artificial retina based on semiconducting polymers
Jan 2021, phys.org

Manuela Ciocca et al. Colour-sensitive conjugated polymer inkjet-printed pixelated artificial retina model studied via a bio-hybrid photovoltaic device, Scientific Reports (2020). DOI: 10.1038/s41598-020-77819-z

Retinal implants can give artificial vision to the blind
Mar 2021, phys.org

via Ecole Polytechnique Federale de Lausanne: Naïg Aurelia Ludmilla Chenais et al. Photovoltaic retinal prosthesis restores high-resolution responses to single-pixel stimulation in blind retinas, Communications Materials (2021). DOI: 10.1038/s43246-021-00133-2

Color blindness-correcting contact lenses
Mar 2021, phys.org

via American Chemical Society: Ahmed E. Salih et al. Gold Nanocomposite Contact Lenses for Color Blindness Management, ACS Nano (2021). DOI: 10.1021/acsnano.0c09657

Saturday, November 26, 2016

Biobots


This image is an illustration by John Tenniel for Alice in Wonderland, and is noted for its ambiguous central figure, whose head can be viewed as being a human male's face with a pointed nose and protruding chin or being the head end of an actual caterpillar, with two "true" legs visible. It has nothing to do with this post really, I was just thinking "cool ass caterpillar picture."
source

Graphene is the world's first two-dimensional material (is it the universe's first...?), because it is one-atom thick, and which sucks because I can't tell my art students that there is no such thing as two dimenional things like circles and squares. I mean technically, graphene is still 3-D, because it's third dimension is as thick as a carbon atom (about 0.3 nanometers), but because no-thing is smaller than the atom-scale, then we can get away with calling it 2-D.

Graphene is a wonder material, and it will change the world "in the same way plastics did," says the guy in this article below. Thing is, it's hard to make. Like quantum computing is great and all, but a qubit is really hard to make. Anyway, that's a bit different now with this headline:

For super-strong silk threads, feed graphene to silkworms

Researchers at Tsinghua University in Beijing fed the one-atom-thick, tremendously tough material to silkworms in one of the first applications of graphene that could become mainstream.

Christian Science Monitor, Oct 2016
http://csmonitor.com/Science/2016/1011/Want-super-strong-silk-threads-Just-feed-the-silkworms-some-graphene