Combining the Best Features of Balsa Wood, Ceramics and NERF®

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

California Institute of Technology (CalTech) floats this imaginary trial balloon to elicit interest in a new material developed by materials scientist Julia Greer and her colleagues.  “Imagine a balloon that could float without using any lighter-than-air gas. Instead, it could simply have all of its air sucked out while maintaining its filled shape. Such a vacuum balloon, which could help ease the world’s current shortage of helium, can only be made if a new material existed that was strong enough to sustain the pressure generated by forcing out all that air while still being lightweight and flexible.” Not only are the scientists achieving the strong, lightweight part of the equation, they are “on the path” to making their new material …

99.99 Percent Air, Thinner Than a Human Hair

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

ScienceDaily reports that, “A team of researchers from UC Irvine, HRL Laboratories and the California Institute of Technology have developed the world’s lightest material — with a density of 0.9 mg/cc — about one hundred times lighter than Styrofoam™.” Their findings appear in the Nov. 18 issue of Science. Looking a bit like a jacks matrix, this “micro-lattice” cellular architecture consists of 99.99 percent air and a lattice of interconnected hollow tubes with a wall thickness 1,000 times thinner than a human hair, according to Dr. Tobias Schaedler of HRL. Despite its extreme lightness, the advanced material is not flimsy.  Squeezing it to 50 percent of its original dimensions does not destroy the lattice.  Instead, it handles the high strain …

Solar Cells – All That Glitters Need Not Be Gold

Dean Sigler Sustainable Aviation Leave a Comment

The search for less expensive solar cells drives many lines of research these days, with trends toward smaller collectors and less expensive materials leading the way.  Many solar cells use gold and other pricey metals to provide junctions within the cell structure.  Gold closed Friday at $1,204.00 per troy ounce on the London Metal Exchange, and nickel at $10.01 per pound.  That would make gold worth $17,558 per avoirdupois pound (14.583 troy ounces per pound), or 1,754 times more expensive than nickel.    According to Gizmag, University of Toronto investigators found that substituting nickel for the previously used gold as collection contacts in their colloidal quantum dot solar cells provided equal performance, at a 40 to 80-percent drop in solar …

Doing More With Much, Much Less

Dean Sigler Uncategorized 1 Comment

This dictum from Paul MacCready that we can do a great deal more with far less material expenditure is well realized in a big way by researchers at the California Institute of Technology (Caltech) with their new type of solar cell. Using about two percent of the silicon semiconductor material normally required for crystalline cells, and achieving a high level of energy conversion, the new cells may also be relatively inexpensive to manufacture. As noted by Harry Atwater in Caltech’s press release, “These solar cells have, for the first time, surpassed the conventional light-trapping limit for absorbing materials…” Atwater is Howard Hughes Professor, professor of applied physics and materials science, and director of Caltech’s Resnick Institute, which according to the …