Magnetocuring: Curing Epoxy With A Magnetic Field

December 30, 2020 by Maya Posch 20 Comments

Who doesn’t love epoxy? Epoxy resins, also known as polyepoxides, are an essential adhesive in many applications, both industrially and at smaller scales. Many polyepoxides however require the application of heat (around 150 °C for most types) in order to cure (harden), which can be complicated when the resin is applied to or inside layers of temperature sensitive materials. Now researchers at Nanyang Technological University (NTU) in Singapore have found a way to heat up resins using an alternating magnetic field (PDF), so-called magnetocuring.

As detailed in the research article by R. Chaudhary et al., they used commercially available epoxy resin and added nano particles of a Mn_xZn_1-xFe₂O₄ alloy. This mixture was exposed to an alternating magnetic field to induce currents in the nano particles and subsequently produce heat that served to raise the temperature of the surrounding resin to about 160 °C in five minutes, allowing the resin to cure. There is no risk of overheating, as the nano particles are engineered to reach their Curie temperature, at which point the magnetic field no longer affects them. The exact Curie temperature was tweaked by changing the amount of manganese and zinc in the alloy.

After trying out a number of different alloy formulations, they settled on Mn_0.7Zn_0.3Fe₂O₄ as the optimal formulation at which no resin scorching occurred. As with all research it’s hard to tell when (and if) it will make it into commercial applications, but if this type of technology works out we could soon be gluing parts together using epoxy resin and an EM field instead of fumbling with the joys of two-component epoxy.

(Thanks, Qes)

The High-Tech Valor Glass Vials Used To Deliver The Coronavirus Vaccine

December 28, 2020 by Kristina Panos 70 Comments

As the world waits for COVID-19 vaccines, some pharmaceutical companies stand armed and ready with an exciting improvement: better vials to hold the doses. Vials haven’t changed much in the last 100 years, but in 2011, Corning decided to do something about that. They started developing an alternative glass that is able to resist damage and prevent cracks. It’s called Valor glass, and it’s amazingly strong stuff. Think Gorilla glass for the medical industry.

Traditionally, pharmaceutical vials have been made from borosilicate glass, which is the same laboratory-safe material as Corning’s Pyrex. Borosilicate glass gets its strength from the addition of boron. Although borosilicate glass is pretty tough, it comes with some issues. Any type of glass is only as strong as its flaws, and borosilicate glasses are prone to some particularly strength-limiting flaws. Pharmaceutical glass must stand up to extreme temperatures, from the high heat of the vial-making process to the bitterly cold freeze-drying process and storing temperature required by the fragile viral RNA of some COVID-19 vaccines. Let’s take a look at how Valor glass vials tackle these challenges.

Continue reading “The High-Tech Valor Glass Vials Used To Deliver The Coronavirus Vaccine” →

How Researchers Used Salt To Give Masks An Edge Against Pathogens

December 19, 2020 by Donald Papp 32 Comments

Masks are proven tools against airborne diseases, but pathogens — like the COVID-19 virus — can collect in a mask and survive which complicates handling and disposal. [Ilaria Rubino], a researcher at the University of Alberta, recently received an award for her work showing how treating a mask’s main filtration layer with a solution of mostly salt and water (plus a surfactant to help the wetting process) can help a mask inactivate pathogens on contact, thereby making masks potentially re-usable. Such masks are usually intended as single-use, and in clinical settings used masks are handled and disposed of as biohazard waste, because they can contain active pathogens. This salt treatment gives a mask a kind of self-cleaning ability.

Analysis showing homogenous salt coating (red and green) on the surface of fibers. NaCl is shown here, but other salts work as well.

How exactly does salt help? The very fine salt coating deposited on the fibers of a mask’s filtration layer first dissolves on contact with airborne pathogens, then undergoes evaporation-induced recrystallization. Pathogens caught in the filter are therefore exposed to an increasingly-high concentration saline solution and are then physically damaged. There is a bit of a trick to getting the salt deposited evenly on the polypropylene filter fibers, since the synthetic fibers are naturally hydrophobic, but a wetting process takes care of that.

The salt coating on the fibers is very fine, doesn’t affect breathability of the mask, and has been shown to be effective even in harsh environments. The research paper states that “salt coatings retained the pathogen inactivation capability at harsh environmental conditions (37 °C and a relative humidity of 70%, 80% and 90%).”

Again, the salt treatment doesn’t affect the mask’s ability to filter pathogens, but it does inactivate trapped pathogens, giving masks a kind of self-cleaning ability. Interested in the nuts and bolts of how researchers created the salt-treated filters? The Methods section of the paper linked at the head of this post (as well as the Methods section in this earlier paper on the same topic) has all the ingredients, part numbers, and measurements. While you’re at it, maybe brush up on commercially-available masks and what’s inside them.

Machining Without Machines

December 18, 2020 by Bryan Cockfield 22 Comments

It’s a luxury to be able to access a modern machine shop, complete with its array of lathes, mills, and presses. These tools are expensive though, and take up a lot of space, so if you want to be able to machine hard or thick metals without an incredible amount of overhead you’ll need a different solution. Luckily you can bypass the machines in some situations and use electricity to do the machining directly.

This project makes use of a process known as electrochemical machining and works on the principle that electricity passed through an electrolyte solution will erode the metal that it comes in contact with. With a well-designed setup, this can be used to precisely machine metal in various ways. For [bob]’s use this was pretty straightforward, since he needed to enlarge an existing hole in a piece of plate steel, so he forced electrolyte through this hole while applying around half an amp of current in order to make this precise “cut” in the metal, avoiding the use of an expensive drill press.

There are some downsides to the use of this process as [bob] notes in his build, namely that any piece of the working material that comes in contact with the electrolyte will be eroded to some extent. This can be mitigated with good design but can easily become impractical. It’s still a good way to avoid the expense of some expensive machining equipment, though, and similar processes can be used for other types of machine work as well.

The Protein Folding Break-Through

December 4, 2020 by Matthew Carlson 22 Comments

Researchers at DeepMind have proudly announced a major break-through in predicting static folded protein structures with a new program known as AlphaFold 2. Protein folding has been an ongoing problem for researchers since 1972. Christian Anfinsen speculated in his Nobel Prize acceptance speech in that year that the three-dimensional structure of a given protein should be algorithm determined by the one-dimensional DNA sequence that describes it. When you hear protein, you might think of muscles and whey powder, but the proteins mentioned here are chains of amino acids that fold into complex shapes. Cells use these proteins for almost everything. Many of the enzymes, antibodies, and hormones inside your body are folded proteins. We’ve discussed why protein folding is important as well covered recent advancements in cryo-electron microscopy used to experimentally determine the structure of folded proteins.

The shape of proteins largely controls their function, and if we can predict their shape then we get much closer to predicting how they interact. While AlphaFold 2 just predicts the static state, the sheer number of interactions that can change a protein, dynamic protein structures are still out of reach. The technical achievement of DeepMind is not to be understated. For a typical protein, there are an estimated 10^300 different configurations.

Out of the 180 million protein sequences in the Protein database, only 170,000 have had their structures identified. Technologies like the cryo-electron microscope make the process of mapping their structure easier, but it is still complex and tedious to go from sequence to structure. AlphaFold 2 and other folding algorithms are tested against this 170,000 member corpus to determine their accuracy. The previous highest-scoring algorithm of 2016 had a median global distance test (GDT) of 40 (0-100, with 100 being the best) in the most difficult category (free-modeling). In 2018, AlphaFold made waves by pushing that up to the high 50’s. AlphaFold 2 brings that GDT up to 87.

At this point in time, it is hard to determine what sort of effects this will have on the drug industry, healthcare, and society in general. Research has always been done to create the protein, identify what it does, then figure out its structure. AlphaFold 2 represents an avenue towards doing that whole process completely backward. Whether the next goal is to map all the proteins encoded in the human genome or find new, more effective drug treatments, we’re quite excited to see what becomes of this landmark breakthrough.

Continue reading “The Protein Folding Break-Through” →

Recovering Metal From Waste

November 30, 2020 by Bryan Cockfield 10 Comments

Refining precious metals is not as simple as polishing rocks that have been dug out of the ground. Often, complex chemical processes are needed to process the materials properly or in high quantities, but these processes leave behind considerable waste. Often, there are valuable metals left over in these wastes, and [NerdRage] has gathered his chemistry equipment to demonstrate how it’s possible to recover these metals.

The process involved looks to recover copper and nitric acid from copper nitrate, a common waste byproduct of processing metal. While a process called thermal decomposition exists to accomplish this, it’s not particularly efficient, so this alternative looks to improve the yields you could otherwise expect. The first step is to react the copper nitrate with sulfuric acid, which results in nitric acid and copper sulfate. From there, the copper sulfate is placed in an electrolysis cell using a platinum cathode and copper anodes to pass current through it. After the process is complete, all of the copper will have deposited itself on the copper electrodes.

The other interesting thing about this process, besides the amount of copper that is recoverable, is that the sulfuric acid and the nitric acid are recoverable, and able to be used again in other processes. The process is much more efficient than thermal decomposition and also doesn’t involve any toxic gasses either. Of course, if collecting valuable metals from waste is up your alley, you can also take a look at recovering some gold as well.

Thanks to [Keith] for the tip!

Continue reading “Recovering Metal From Waste” →

Lithium: What Is It And Do We Have Enough?

November 30, 2020 by Matthew Carlson 138 Comments

Lithium (from Greek lithos or stone) is a silvery-white alkali metal that is the lightest solid element. Just one atomic step up from Helium, this magic metal seems to be in everything these days. In addition to forming the backbone of many kinds of batteries, it also is used in lubricants, mood-stabilizing drugs, and serves as an important additive in iron, steel, and aluminum production. Increasingly, the world is looking to store more and more power as phones, solar grids, and electric cars continue to rise in popularity, each equipped with lithium-based batteries. This translates to an ever-growing need for more lithium. So far production has struggled to keep pace with demand. This leads to the question, do we have enough lithium for everyone?

It takes around 138 lbs (63 kg) of 99.5% pure lithium to make a 70 kWh Tesla Model S battery pack. In 2016, OICA estimated that the world had 1.3 billion cars in use. If we replace every car with an electric version, we would need 179 billion pounds or 89.5 million tons (81 million tonnes) of lithium. That’s just the cars. That doesn’t include smartphones, laptops, home power systems, massive grid storage projects, and thousands of other products that use lithium batteries.

In 2019 the US Geological Survey estimated the world reserves of identified lithium was 17 million tonnes. Including the unidentified, the estimated total worldwide lithium was 62 million tonnes. While neither of these estimates is at that 89 million ton mark, why is there such a large gap between the identified and estimated total? And given the general rule of thumb that the lighter a nucleus is, the more abundant the element is, shouldn’t there be more lithium reserves? After all, the US Geological Survey estimates there are around 2.1 billion tonnes of identified copper and an additional 3.5 billion tonnes that have yet to be discovered. Why is there a factor of 100x separating these two elements?

Continue reading “Lithium: What Is It And Do We Have Enough?” →