I’m probably just getting old, but I always swallow hard when I see discussion of plastics in the popular media. The current issue of Time, for example, has a one page article titled “Freshen Up Your Drink” under the heading of “health”. The article tackles the subject of whether it’s OK to re-use water bottles, and looks at the case for single-use PET, polycarbonate, HDPE and stainless steel. A table with the article states that HDPE is “made from petroleum”. Are people supposed to believe that PET and polycarbonate are not derived from petroleum? Possibly they are made from some magical substance that is totally benign from an environmental and health viewpoint. The article states that “PET degrades with use”, but that there are “no known problems” with HDPE. My goodness, HDPE, which is a lower quality material than PET, does not degrade with use? And wait a minute, weren’t we just told five minutes ago by the green lobby that we want this stuff to degrade?
The article tells Time readers to dispose of PET containers after a single use (or re-use them as flower pots!), re-use HDPE containers because they are safe, and re-use stainless containers because they are as safe as glass. Time indicates that scientists have concerns with BPA leaching from PC even at room temperature. The article cautions readers not to fill stainless containers with hot water, but makes no such admonition for HDPE! The melting point for stainless is around 2600F; HDPE, 430F!
I remember 30 or so years ago how much I hated all of the broken glass litter left from people who smashed beer bottles. Today, I do see some trash of cans or plastic bottles, but at least they aren’t a safety hazard. And now we’re worrying about whether it’s safe to re-use plastic containers? OK, but let’s at least make sure we make some sense from a technical perspective.
Artificially created metamaterials are already appearing in niche applications like electronics, communications, and defense, says a new report from Lux Research. How quickly they become mainstream depends on cost-effective manufacturing methods, which will include additive manufacturing.
SpaceX has 3D printed and successfully hot-fired a SuperDraco engine chamber made of Inconel, a high-performance superalloy, using direct metal laser sintering (DMLS). The company's first 3D-printed rocket engine part, a main oxidizer valve body for the Falcon 9 rocket, launched in January and is now qualified on all Falcon 9 flights.
Lawrence Livermore National Laboratory and MIT have 3D-printed a new class of metamaterials that are both exceptionally light and have exceptional strength and stiffness. The new metamaterials maintain a nearly constant stiffness per unit of mass density, over three orders of magnitude.
Smart composites that let the material's structural health be monitored automatically and continuously are getting closer to reality. R&D partners in an EU-sponsored project have demonstrated what they say is the first complete, miniaturized, fiber-optic sensor system entirely embedded inside a fiber-reinforced composite.
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