Gizmag and Science Daily both covered a propulsion system that’s been with us for many decades, but which is just now seeing practical applications in space flight, and may be adapted to terrestrial winged vehicles. Your editor might have passed it over as overhyped, but the research came from the Massachusetts Institute of Technology (MIT) and was published in The Proceeding of the Royal Academy – two good indicators of veracity. Jennifer Chu of MIT’s News Office explains, “When a current passes between two electrodes — one thinner than the other — it creates a wind in the air between. If enough voltage is applied, the resulting wind can produce a thrust without the help of motors or fuel.” That phrase, “If enough voltage is applied…” is a significant qualification. “Electrohydrodynamic thrust,” or “ionic wind” has been known since the 1960s, but limited to hobbyists and science fair projects. This video from China demonstrates the use of electric thrusters to …
A broader Overview of Biofuels
Are biofuels truly “green?” Gizmag this morning has an entry on Empa, the Swiss Federal Laboratories for Materials Science and Technology, which has just released a report showing that biofuels may not always be as green as we would like to think. Further, they note that gasoline, including that coming from shale oil sands (as in Keystone XL pipeline oil) may be cleaner than certain crop-derived combustibles. The headlines may stoke controversy, so it’s worthwhile to examine the short-form charts and press release, and compare the impressions gained from a quick glance with those from reading the 113-page study itself. Empa’s press release headline and lead give the impression that things are grim in the green world. The headline “Most biofuels are not ‘green’” is followed by “First tops, then flops. That is one way of summing up the history of biofuels so far. A new study led by Empa gives an up-to-date picture of the ecobalance of various biofuels …
Nano to Macro – Piezoelectrics Have Power
Two far-flung enterprises are using piezoelectric devices to generate answers to widely disparate questions. The first set of questions is intensely personal. “Can a heart implanted micro robot operate permanently? “Can cell phones and tiny robots implanted in the heart operate permanently without having their batteries charged? These provocative questions highlight a web page from KAIST, the Korea Advanced Institute of Science and Technology, which focuses on the Institute’s work with piezoelectric devices. Such devices can tranform vibrations, pressure, and other mechanical forces into an electric current. Older “hi-fi” systems used piezoelectric cartridges in their LP-playing tone arms to transduce the vibrations from a needle touching the record’s grooves into signals to the system’s amplifier. Dr. Zhong Lin Wang explains, “Our FAND (Flexible and Nano-bio-energy Device Lab) group has developed new forms of highly efficient flexible nanogenerator technology using freely bendable piezoelectric ceramic thin film nano-materials and nanocomposite materials that can convert the tiny movements of human body (such as …
How Many iPods in a BiPod?
David Bettencourt, a defense attorney in Hawaii and a regular reader of the blog, sent this note about Burt Rutan and his early interest in hybrid power for aircraft. According to David, “A July 2000 Road & Track interview of Burt Rutan regarding the hybrid Honda Insight might be of interest. It stated: “Does he see any application of hybrid propulsion for airplanes? An innocent question, although it leaves Rutan unusually silent. ‘Gee, maybe I shouldn’t disclose this in Road & Track. But at the risk of someone else doing this first, let me tell you about an airplane that would be really interesting to do. This is fascinating….’ “Rutan leans back and stares into middle distance. ‘Visualize an electric airplane with enough batteries to climb to about 500 feet. Actually, it would have several small electric motors with small propellers scattered all around the airplane—some on the tail, some on the wings—so if one motor seized, it’s just a …
Drs. Seeley and Moore Hit One Out of the Airpark
The January 2011 issue of Popular Mechanics resurrects the perennial hope for a flying automobile. The cover taunts, “(Go Ahead, Laugh) But NASA, DARPA & the FAA Are Serious.” Sharon Weinberger taunts some makers a bit in her article, “Driving on Air,” as she looks at a variety of Transformer-style vehicles that can travel by land or air with the fewest inconveniences. She notes the differences between propelling cars and planes, and looks at extremely different modes of giving people personal aerial transport, including the Moeller Skycar (“Inventor Paul Moeller has been developing the concept for nearly 50 years. To date, the M400X has only hovered on a tether.”), the Martin Jetpack, The Cartercopter, and the Terrafugia Transition that’s been getting an enormous press following (and a featured spot in the Hammacher Schlemmer Christmas catalog) lately. She ends with an overview of Dr. Mark Moore’s Puffin, detailed in this blog in January. After explaining that a commuter using the Puffin would rise …
Solar Cells – All That Glitters Need Not Be Gold
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 cell prices. Following that math, current pricing of solar cells such as Ascent’s thin film units at $6.00 per Watt could drop to $2.40 to $1.20 per Watt; near the $1.00 per Watt goal many cell makers have long sought. …