Australian researchers figure out a new way to apply extreme pressure and squeeze out diamonds.
- Diamonds aren't just beautiful. They're also excellent at cutting through most anything.
- Researchers have worked out how to create the gems without the high temperatures that accompany their natural formation.
- The researchers were able to create two different types of diamonds that also occur naturally.
The totally crushed it<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDgyNzYxOC9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYxMjc2MjA5OH0.Td-IiqixMYd-0OEn3vunxg5gFbPEyzKiSVOcxr6rdDs/img.png?width=980" id="75686" class="rm-shortcode" data-rm-shortcode-id="fe32f066e6fc40c8b19a793828a97b4b" data-rm-shortcode-name="rebelmouse-image" />
The telltale clue<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDgyNzYyNi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY2NDAxODQ2Nn0.yVllyyJOAk7No8cnTPyQQMky00Q8awt0KfPDHF95ud4/img.png?width=980" id="45646" class="rm-shortcode" data-rm-shortcode-id="b3d62e6d2b2a26dc2cc73b4de24519e6" data-rm-shortcode-name="rebelmouse-image" />
Credit: kento/Adobe Stock<p>The rest of the team's formula has to do with how the pressure is applied.</p><p>Co-leader of the research, <a href="https://www.rmit.edu.au/contact/staff-contacts/academic-staff/m/mcculloch-professor-dougal" target="_blank">Dougal McCullough</a>, and his team working at RMIT used cutting-edge advanced electron microscopy to image slices of experimental diamond samples that provided a peak into their formation.</p><p>One revelation was the relationship between the two diamond types. "Our pictures showed that the regular diamonds only form in the middle of these Lonsdaleite veins," says McCulloch. "Seeing these little rivers of Lonsdaleite and regular diamond for the first time was just amazing and really helps us understand how they might form."</p><p>"The twist in the story ," says Bradby, "is how we apply the pressure. As well as very high pressures, we allow the carbon to also experience something called 'shear' — which is like a twisting or sliding force. We think this allows the carbon atoms to move into place and form Lonsdaleite and regular diamonds."</p><p>The diamonds produced by the team confirm this idea. Bradby recalls, "Seeing these little rivers of Lonsdaleite and regular diamond for the first time was just amazing and really helps us understand how they might form [in nature]."</p>
New diamonds made to order<p>"Creating more of this rare but super-useful diamond is the long-term aim of this work," says Bradby.</p><p>While many may think of diamonds only for their ornamental value, their hardness makes them excellent for cutting through most anything, and they're used in some of the world's most advanced precision cutting systems.</p><p>Bradby notes that, "Lonsdaleite [in particular] has the potential to be used for cutting through ultra-solid materials on mining sites."</p><p>Next up: flight and x-ray vision. (Joking.)</p>
While it's always been a boon to Popeye's "muskles," it looks like spinach may also have a role to play in clean future batteries.
- Scientists are seeking sustainable, clean chemicals for use in future fuel cell and metal-air batteries.
- Platinum is the current go-to substance for battery cathode catalysts, but it poses a number of problems, including high cost and instability.
- Chemists at American University have developed a new high-performance catalyst from simple spinach, although its preparation as a catalyst is anything but simple.
Cathodes and anodes, oh my<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2OTU5MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNDQ0NjA0OH0.Fe2eDSkzfzSBG3bGwDsEdrxOy14JYGuhJGjm9shhtkg/img.jpg?width=980" id="5e913" class="rm-shortcode" data-rm-shortcode-id="22095dc5998edbe5c1e27ec10b5a4cc9" data-rm-shortcode-name="rebelmouse-image" />
Flow of energy when battery is in use, discharging
Credit: VectorMine/Shutterstock/Big Think<p>Electrons travel within a battery from one electrode, called the anode, through the battery's electrolyte — either a powder or liquid barrier — to another electrode, called the cathode. The anode releases these electrons through a chemical process called oxidation, while the cathode accepts them through another, an oxygen reduction reaction. Together, this exchange is called a "<a href="https://en.wikipedia.org/wiki/Redox" target="_blank">redox</a>."</p><p>The electrons' return trip back to the anode, however, requires a "load" provided by an external device, which is fine, since that device — a flashlight, a phone, or a car, for example — operates on the energy produced by the battery's electrons passing through.</p><p>The electrons travel out from the cathode's positive terminal to the device then return to the battery's negative anode terminal. In this way the energy travels <a href="https://www.explainthatstuff.com/batteries.html#parts" target="_blank">round and round</a> the battery-device circuit. (When charging a battery, electrons go in the opposite direction connected to a charger.)</p><p>The new study is concerned with the <a href="https://en.wikipedia.org/wiki/Catalysis" target="_blank" rel="noopener noreferrer">catalyst</a> that produces the cathode's oxygen reduction reaction.</p>
Replacing a problematic, pricey catalyst<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2OTU5Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMjYyNDI1Nn0.pI9itmS82CPFV4nUOAURwP9amjNi6HpPpU2biikLxYs/img.jpg?width=980" id="9685a" class="rm-shortcode" data-rm-shortcode-id="3a29c292ad8026d129250d041f1fac9e" data-rm-shortcode-name="rebelmouse-image" alt="platinum bricks" />
Credit: AlexLMX/Shutterstock<p><a href="https://en.wikipedia.org/wiki/Fuel_cell" target="_blank" rel="noopener noreferrer">Fuel cell batteries</a> and <a href="https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell" target="_blank">metal-air batteries</a> use the surrounding air outside the battery as their cathode. It's clean, free, plentiful, and it works, as long as there's a catalyst that can adequately prompt the requisite oxygen reduction reaction.</p><p>The most commonly used catalysts for such batteries have been based on platinum. There are problems with these, though. Of course, platinum is expensive. Also, as the study notes, "the lack of long-term stability and the vulnerability to surface poisoning by various chemicals such as methanol and carbon monoxide, call for the development of non-Pt group metal (NPGM) catalysts."</p><p>Researchers have therefore been exploring non-toxic, carbon-based catalyst alternatives since they may be more stable and exhibit resistance to surface poisoning. And because carbon is everywhere, they'd be inexpensive to produce. However, some of the materials being investigated don't do the job as well as platinum-based catalysts. The chemical reaction they produce is slow, posing a speed bottleneck to the flow of electrons.</p>
Enter spinach<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2OTYwMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjIxNzI1MX0.Ru_hwAVllm7R2mCfu0X94MdVXpCYbZz3VjcfvsRMaTo/img.jpg?width=980" id="6321d" class="rm-shortcode" data-rm-shortcode-id="f8285054c63c2fc02bef8fba3b29a7cf" data-rm-shortcode-name="rebelmouse-image" />
Credit: Liu, et al./ACS Omega 2020, 5, 38, 24367-24378<p><span style="background-color: initial;"><a href="https://www.american.edu/cas/faculty/szou.cfm" target="_blank">Shouzhong Zou</a></span>, of American University's <a href="https://www.american.edu/cas/chemistry/" target="_blank">Department of Chemistry</a>, is the paper's senior author. The lead author is Xiaojun Liu, with Wenyue Li as co-author. Professor Zou reports:</p><p style="margin-left: 20px;">"The method we tested can produce highly active, carbon-based catalysts from spinach, which is a renewable biomass. In fact, we believe it outperforms commercial platinum catalysts in both activity and stability. The catalysts are potentially applicable in hydrogen fuel cells and metal-air batteries."</p><p>While other catalyst research has involved plants such as rice and cattails, Zou believes spinach has a few things that make it a superior candidate as a catalyst material. For one thing, it's rich in iron and nitrogen, both essential catalyst ingredients. In addition, it's easy and inexpensive to grow, and it's abundant.</p><p>Zou and his students developed spinach-based carbon nanosheets a thousand times thinner than a human hair. The process is complex, a combination of basic and advanced techniques.</p><p>To begin, the researchers washed, juiced, and freeze-dried the vegetable before grinding it by hand into a fine powder using a mortar and pestle. Next, the spinach powder was dissolved and mixed with <a href="https://en.wikipedia.org/wiki/Melamine" target="_blank">melamine</a>, sodium chloride, and potassium chloride in water and cooked together at 120°C. This mixture was then rapid-cooled in liquid nitrogen and freeze-dried. Then it was <a href="https://en.wikipedia.org/wiki/Pyrolysis" target="_blank">pyrolized</a> twice.</p><p>It may well have been worth the effort. Measurements of the resulting nanosheet indicated that it can out-perform platinum as a catalyst in both speed and stability. Of course, that's on top of being made from such an unassuming, inexpensive, and widely available plant.</p><p>"This work," says Zou, "suggests that sustainable catalysts can be made for an oxygen reduction reaction from natural resources." The next step for Zou and his students is to try out their spinach catalyst in prototype fuel cells to assess its performance in action. They're also looking into the use of other plant materials for catalysts.</p><p>Finally, Zou understandably hopes to develop a simple, less energy-intensive way to make their catalyst nanosheets.</p>
New prototype Petri dishes let ordinary scientists in on the advanced technology.
- Acoustic tweezers allow bioparticles and cells to be precisely manipulated without touching them.
- Sound waves grab and move very tiny objects as desired.
- Previously available only in expensive and complex devices, acoustic tweezers have now been built into Petri dishes.
When a tweezer is not a tweezer<p>To understand how the "tweezers" work, it's important to know that they're tweezers only in that they grab objects so that they can be manipulated. That's the extent of their similarity to household tweezers: Acoustic tweezers are not small hand-held devices to pinch with. They're much more high-tech than that. <a href="https://en.wikipedia.org/wiki/Acoustic_tweezers" target="_blank">Acoustic tweezers</a> use pairs of sound waves directed at the object to be manipulated. (NASA has an <a href="https://www.nasa.gov/specials/X59/science-of-sound.html" target="_blank">excellent pair of short videos</a> explaining how sound waves work.)</p><p>In an acoustic tweezer, sound waves directed toward each other push an object into the location at which the waves meet, called a "trapping node." Once the object is trapped there, the node's position can be repositioned as desired by adjusting the strength, or amplitude, of the sound waves. As the node moves, so does the object trapped within it.</p><p>Acoustic tweezers provide a touch-free, gentle and non-destructive means of holding on to and manipulating even very tiny objects — a single cell or particle, for example. Using multiple sound waves emitted from opposite each other, and above and below, objects can be moved in three dimensions. This allows scientists to mix objects together with tremendous precision and to construct two-dimensional and three-dimensional structures from trapped objects. </p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzk5MjAyOC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MDY2Mjg4Mn0.5cMqhSjZa6eo8ISWnY37j3R9UtMsEHV9qGAh2EC53i4/img.jpg?width=980" id="fb16a" class="rm-shortcode" data-rm-shortcode-id="2acb472e02638d001a5e0ccdc9c8b6e8" data-rm-shortcode-name="rebelmouse-image" alt="graphic explaining how sound waves move objects" />
Graphic explaining how sound waves move objects
Credit: Big Think
How the prototypes work<p>The researchers present three different prototypes in their paper. They all employ small <a href="https://en.wikipedia.org/wiki/Piezoelectricity" target="_blank">piezoelectric</a> <a href="https://blog.teufelaudio.com/transducers/" target="_blank">sound transducers</a> affixed to the edges and/or below Petri dishes. These transducers convert electrical energy into sound waves and can move objects in Petri dishes in pretty much any direction.</p><ul><li>The first prototype has four transducers arrayed around the four quadrants of a Petri dish, allowing the tweezers to move targeted objects laterally.</li><li>The second model uses a tilted sound transducer beneath the Petri dish that creates a whirlpool in its center capable of capturing, concentrating, and mixing the contents of a dish.</li><li>The third design fits two transducers beneath the dish together like a zipper, forming a holographic IDT (interdigital transducer.) This highly configurable arrangement generates high-frequency beam-like waves from below the dish. They can be programmed as 3D focused or vortex beams, for example, allowing them to perform a range of object manipulations.</li></ul><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzk5MjExOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyODA1ODkzM30.ypFFEBKMYg0iBNvAQ3aiF07-UK8OM8nACZTQTM9unds/img.jpg?width=980" id="120f9" class="rm-shortcode" data-rm-shortcode-id="dc8c535494b9830e1a1a594d8495b2c1" data-rm-shortcode-name="rebelmouse-image" />
Credit: Tian, et al./Scientific Advances
Moving forward<p>The primary purpose of this study was to work out how to implement already available acoustic tweezers in more compact, practical form for researchers, according to Huang.</p><p>As the paper notes: "Although previous acoustic tweezers have been demonstrated for the manipulation of cells, most of them require customized microfluidic channels/chambers, which usually require time-consuming and costly steps for fabrication and sterilization and hence are not frequently used in biological and biomedical laboratories." The authors' aim, says the paper, was to develop "acoustic tweezer devices that can directly manipulate bioparticles in the most common laboratory cell culture plate, the Petri dish."</p><p>The authors' next goal is to further catalogue the capabilities of their prototypes, in particular their configurable third design. Down the road, they hope, will be development of a device that combines all three types of functionality provided by the prototypes in a single device.</p>
Dust sticking to things on the moon is a serious problem researchers are trying to solve.
Sticky situation<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU5OTA1Mi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MDAyMzU0MH0.lfYLUy2mETdXOgEGdyEHPUJD2aXqab9qB-WoMp94ldk/img.jpg?width=980" id="a045b" class="rm-shortcode" data-rm-shortcode-id="40f701f33214c9cfdb248d88a49d0ca9" data-rm-shortcode-name="rebelmouse-image" />
Microscopic view of man-made "moon dust"
Credit: IMPACT lab/CU Boulder<p>Lunar dust is not much like the stuff settling on the surfaces of your home. For one thing, Wang reports, "Lunar dust is very jagged and abrasive, like broken shards of glass."</p><p>The reason that it's so stubbornly sticky is that it carries an electric charge not unlike that of a sock you've just removed from the dryer. The charge results from being continually exposed to the Sun's radiation as the dust sits on the lunar surface unprotected by an atmosphere like ours. The moon does have very thin atmosphere that contains odd gases such as sodium and potassium, <a href="https://www.nasa.gov/mission_pages/LADEE/news/lunar-atmosphere.html" target="_blank">says NASA</a>, but it isn't thick enough to afford much protection from radiation.</p>
Overload of electrons<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="ea957f6f96e5b4796909ee398cc65658"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/-aHHWAeda6o?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>The researchers explored the idea of shooting a beam of electrons at lunar dust to fill the spaces between its particles with negative charges that could push the particles further apart, away from each other and also off a surface to which they might be adhering. Says Wang, "The charges become so large that they repel each other, and then dust ejects off of the surface."<br></p><p>To test their concept, the researchers acquired <a href="https://www.nasa.gov/sites/default/files/atoms/files/nasa_tm_2010_216446_simuserg.pdf" target="_blank">lunar regolith stimulant</a> from NASA, a substance formulated on Earth that's designed to replicate lunar dust. They placed objects of various materials that had been coated with the stuff in a vacuum chamber and fired electron beams at them. (The video above shows the dust's response.)</p><p>Speaking of the behavior of the electron-blasted dust on a number of tested surfaces, including spacesuit fabric and glass, "It literally jumps off," says lead author <a href="https://www.mendeley.com/authors/57218515747/" target="_blank" rel="noopener noreferrer">Benjamin Farr</a>. However, the finest-grained regolith, the kind that gets stuck in brushes, remained unperturbed by the electrons. Overall, the electrons cleaned off about 75 percent to 85 percent of the dust. "It worked pretty well, but not well enough that we're done," says Farr. Looking forward, the team is exploring ways in which the electron beam's cleaning power can be increased.</p><p>This is not the first attempt at using electrons to clean up lunar dust. For example, NASA has explored using <a href="https://www.seeker.com/space/exploration/new-spacesuit-system-could-repel-destructive-moon-dust" target="_blank">nanotube electrode networks</a> in spacesuits to keep dust off. <a href="https://www.nasa.gov/feature/goddard/2019/nasa-s-coating-technology-could-help-resolve-lunar-dust-challenge" target="_blank" rel="noopener noreferrer">To keep regolith off other materials</a>, NASA is also considered combining charge-dissipating indium tin oxide with paint that could then be applied to otherwise dust-collecting surfaces.</p><p>The CU Boulder team anticipates one day hanging up a spacesuit in a room or compartment where it can be bombarded with electrons for cleaning. Even more convenient would be facilities where "You could just walk into an electron beam shower to remove fine dust," says study coauthor <a href="https://www.colorado.edu/physics/mihaly-horanyi" target="_blank">Mihály Horányi</a> of CU Boulder's <a href="https://www.colorado.edu/physics/" target="_blank" rel="noopener noreferrer">Department of Physics</a>.</p>
Ever wonder how soft hair can dull a steel razor? So did scientists at MIT.
- Steel is fifty times harder than hair, yet shaving razors dull in a hurry.
- A new study finds much of this is caused by hair cracking razors at points of imperfection.
- The findings may lead to new ways of making razors that last longer.
An extremely magnified image of a razor blade cutting hair.
G. Roscioli<p>Lead author Gianluca Roscioli grew his facial hair out for three days before <a href="https://www.smithsonianmag.com/smart-news/why-razors-are-dull-within-weeks-according-science-180975534/" target="_blank">shaving</a>. He then brought his razors into the lab to examine them under an electron microscope. While the team expected to see even dulling on the blade edge, they instead noticed strange C-shaped chips missing. Intrigued, they attached a camera to the microscope so they could record the blade cutting the <a href="https://www.sciencemag.org/news/2020/08/your-hair-can-crack-steel-when-it-hits-right-spot" target="_blank">hair</a>. At the same time, they investigated the properties of the razors at the microscopic level.</p><p>This apparatus revealed that, when the razor blade hit the hairs at non-perpendicular angles, small cracks formed. These tended to develop in boundary areas between where the steel was harder and where it was softer due to differences in the properties at each location caused by the manufacturing <a href="https://www.newscientist.com/article/2251202-we-just-figured-out-why-shaving-soft-hair-blunts-steel-razor-blades/" target="_blank">process</a>. Over time, these cracks grew into chips. While these chips are too small to see with the naked eye, they were large enough to reduce the blade's effectiveness.</p><p>Roscioli told <a href="https://www.smithsonianmag.com/smart-news/why-razors-are-dull-within-weeks-according-science-180975534/" target="_blank" rel="noopener noreferrer dofollow">NPR</a>, "The size of the chips are about 1/10 of the diameter of a human hair."</p><p>The chips can be caused by hair of any thickness and appear to be unavoidable in blades with standard imperfections. </p><p>The finding surprised other scientists, who also quickly accepted the explanation. Professor Suveen Mathaudhu of UC Riverside explained to <a href="https://www.npr.org/2020/08/06/898577234/cutting-edge-research-shows-how-hair-dulls-razor-blades" target="_blank" rel="noopener noreferrer dofollow">NPR</a> that he had expected a larger role in the dulling process to be played by corrosion but that the findings made a great deal of sense. Other scientists expressed how impressed they were by the quality of the images and the difficulty of the study. </p>