Cool STEM News

Scientists develop a truly recyclable plastic. | Fast company (01:13)

• It was estimated that back in 2010 that 5 to 13 million metric tons (Mt) of plastic waste entered the ocean from both developing countries and high-income countries.
  • From 2010 to 2016, it is estimated that global plastic production increased 26% from 334 to 422 Mt
  • An estimated 91% of all plastic isn’t recycled at all.
• Researchers from the Lawrence Berkeley National Laboratory and the Department of Energy have been studying an enticing, new type of plastic.
  • Polydiketoenamine, or PDK
• “The idea here is that we’re designing new polymers with ease of recycling in mind,” says Corinne Scown, staff scientist and deputy division director at Lawrence Berkeley National Lab.
• Plastics are chains of identical molecules called monomers, which link together into the polymers we know as plastic.
  •  Additives can enter the mix to customize the material for different purposes.
• Unlike usual plastics that are melted down utilizing heat, PDK plastics are manufactured in such a way that they can be melted down by acid.
  • Cleanly separating the monomers from additives.
  • Allowing for monomers to be reused in the next batch of plastic creation.
• Scown talks about the applicability of this new polymer: “There’s still a lot of testing to be done to understand what applications, packaging, and durable product applications this is good for, and how we might tailor new monomers in the future to get the specifications we want … It’s not like this is going to replace all plastics tomorrow. There will be some applications where it works and others where it doesn’t in its current form.”
  • Costs 10 to 20 times more than regular plastics for virgin batches due to production not being scaled or becoming more efficient.
• Could be good for higher-end products, that cost more where plastic creation is a small part of the overall cost. 

High-tech contact lenses are straight out of science fiction | The Conversation (08:43)

• Monitoring Pressure:
  • Researchers at the University of Illinois at Chicago have developed a prototype of a contact lens that continuously monitors changes in intraocular pressure, the pressure within the eyeball. 
  • Normal pressure is 10 and 21 mmHg.
  • The shape of the eyeball varies in response to changes in intraocular pressure allowing for the contact utilizing an embedded thin capacitor to correlate the shape change to the pressure. 
  • The lens could continuously monitor for glaucoma (increase in pressure) and could indicate it early enough to release a drug to combat it.
    • A similar lens, called Sensimed Triggerfish, has received regulatory approval in the United States and Japan.

• Built-in LCD Display:
  • California-based tech start-up Mojo Vision is working on contact lenses with an inbuilt LCD display.
  • The contact lens can provide a wide range of information, from phone notifications, map directions, and more.

• Read the final paragraph of the article which I thought was a good way to end it:
  • “The global contact lens market is predicted to expand, and we can expect to see a plethora of ground-breaking products being released. And as technology continues to develop contact lenses, smart contact lenses may one day replace smartphones and screens.” 

Lobster Underbelly Inspires Nanofibrous Hydrogel Tech for Tissue Engineering | GenEngNews (15:29)

• A team of Massachusetts Institute of Technology (MIT) researchers has developed a nanofibrous hydrogel-based material that mimics the structure of a lobster’s underbelly and is potentially strong and stretchy enough to be used to make replacement tissues such as artificial tendons and ligaments. 
• A lobster’s underbelly is lined with a thin, translucent membrane that is stretchy and surprisingly tough.
  • Protects the lobster as it moves across the seafloor, while also allowing it to flex back and forth to swim.
• The researchers stated that the extraordinary mechanical properties of the underbelly are “mainly attributed to its unique multi-layered nanofibrous structure”
• Nanofibrous hydrogels are found in both animal and plant bodies and are also seen in engineering applications.
  • As noted by the researchers: “[N]anofibrous hydrogels have been explored in diverse applications, including tissue regeneration, ionic skin, hemostatic dressings, cartilage repair, imperceptible textile sensors, printable electrodes for flexible implants, tissue adhesives, and small-scale bio-robots.”
  • Hydrogel – a gelatin-like class of materials made primarily of water and cross-linked polymers.
• In 2019 these same researchers created a fatigue-resistant material by utilizing ultrathin fibers of hydrogel. 
• For their newly reported development, the researchers combined a number of techniques to create stronger hydrogel nanofibers. 
  • Utilizing these techniques to mimic the lobster’s underbelly in the material. 
  • For example: “We prepared aligned nanofibers by electrospinning to mimic the chitin fibers that existed in the lobster underbelly,” according to Jiahua Ni co-author on the paper.
• The researchers ran the material through a battery of stretch and impact tests, and showed that the synthetic material is remarkably “fatigue resistant,” and able to withstand repeated stretches and strains without tearing. 
  • 50 times more fatigue resistant than the conventional nanofibrous hydrogels
• The team concluded, “In this work, we provide a general strategy to design fatigue-resistant nanofibrous hydrogels by engineering nanofibers and nanocrystalline domains across varying length scales … This work suggests an avenue toward the next generation of nanofibrous hydrogels for diverse emerging applications, including lightweight physical protection, textile electronics, smart clothing, and tissue engineering scaffolds.”

Jetoptera VTOL aircraft design features “bladeless fans on steroids” | New Atlas (21:33)

• Jetoptera’s J-2000 concept is a remarkably different take on the VTOL inter-city aircraft, designed to make use of the company’s own unique propulsion system.
• Fluidic propulsion systems (FPS) 
  • Uses a small, quiet impeller to generate pressure around an aerodynamically shaped loop until it exits at high speed through a slit running around the ring.
  •  air is forced back over a wing-shaped surface all around the ring generating a “lift”
  • That lift is canceled out by equal negative pressure zones all around the ring
  • Creating a pressure vortex in the center of the ring that pulls ambient air through at a great rate.
• These designs can end up sucking through 15 times the volume of air initially fed through the ring by the compressor.
• It is using gas generators, including a 75-kW turboshaft system for larger propulsion system tests. Since the technology to utilize an electric compressor is not there yet.
  • Will need batteries to reach energy density figures around 1,500 Wh/kg.
  • Current state-of-the-art batteries are around 260 Wh/kg. (600% Improvement)
• According to the company, this kind of system “improves propulsive efficiency by more than 10 percent while lowering fuel consumption by more than 50 percent compared to small turbojets. The propulsion system saves approximately 30 percent in weight compared to turbofans or turboprops and also significantly reduces complexity.”
• Provides flexibility to how the VTOLs are designed, taking up much less space on a vertipad than most transitioning lift/cruise eVTOLs or traditional helicopters.
• Jetoptera is planning an entire family of aircraft around this design. 
• Still at the prototyping phase. 
  • Flown several subscale models but not to the extreme-scale they are referencing in the J-2000 design (2,000lbs).
• Jetoptera only plans for this machine to be a demonstrator platform; it doesn’t want to get caught up in the certification nightmare of aircraft development and would prefer just to be building propulsion systems for other aircraft manufacturers.

Meet the World’s Most Powerful Tidal Turbine: The O2 | Interesting Engineering (28:26)

• The Orbital 02, purportedly the “world’s most powerful” tidal turbine successfully launched from the Port of Dundee on Thursday, April 22nd.
  • Designed and built by Orbital Marine Power
  • Video of the Design on Youtube
• Once operational, the turbine will kick out nearly 2 megawatts of power. That is enough to power at least 2,000 homes in the UK every year.
• The turbine will be connected to the European Marine Energy Centre off the Orkney Islands. 
  • Orkney Island – Part of the UK (North of UK)
• The Orbital O2 will comprise of a 73m long floating superstructure, with rotor diameters of 64 feet, it will have an over 6400 sq feet rotor area, the largest ever on a single tidal generating platform to date. 
• The turbine will also feature something called a “gull-wing” style set of retractable legs.
  • Especially for ease of maintenance and repair. 
• Each turbine can rotate a full 360-degrees, which will allow the turbine to generate power without the need for the entire turbine to change direction when the tides do. 
• Dynamic control of the rotors will enable power to be captured from various tidal directions without the need to yaw the entire platform. 
• Speaking of the launch, Orbital’s CEO, Andrew Scott, said: “This is a huge milestone for Orbital; the O2 is a remarkable example of British cleantech innovation, and the build we have completed here is an inspiring display of what a UK supply chain can achieve if given the opportunity – even under the extraordinary pressures of a pandemic.”