Fixed Wings Find Their Way

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Dynamic presentations by Sebastian Thrun and Nicholas Roy have alerted and informed CAFE Foundation’s Electric Aircraft Symposia attendees of highly sophisticated efforts to allow autonomous full-size automobiles and miniature helicopters to navigate through or over unfamiliar terrain. Using clues from lasers, infrared sensors, inertial guidance systems and sometimes GPS coordinates, the vehicles use control algorithms to guide themselves around obstacle-strewn courses. As noted in Science Daily and the The Massachusetts Institute of Technology’s press office this week, “Dozens of research teams have competed in a series of autonomous-helicopter challenges posed by the Association for Unmanned Vehicle Systems International (AUVSI); progress has been so rapid that the last two challenges have involved indoor navigation without the use of GPS.” Mini-copters have shown an amazing ability to not only navigate, but to perform complex tasks in swarms, such as building large architectural assemblies – all without human intervention (other than, one assumes, someone pushing a “go” button). MIT’s Robust Robotics Group has …

The Artificial Leaf

Dean Sigler Electric Powerplants Leave a Comment

Daniel Nocera, Henry Dreyfus Professor of Energy and professor of chemistry at Massachusetts Institute of Technology (MIT), has caused a stir in the scientific community and attracted press attention including a recent feature article in the May 14 New Yorker. MIT’s own press release makes it sound all too simple and immediately appealing. “The artificial leaf — a silicon solar cell with different catalytic materials bonded onto its two sides — needs no external wires or control circuits to operate. Simply placed in a container of water and exposed to sunlight, it quickly begins to generate streams of bubbles: oxygen bubbles from one side and hydrogen bubbles from the other. If placed in a container that has a barrier to separate the two sides, the two streams of bubbles can be collected and stored, and used later to deliver power: for example, by feeding them into a fuel cell that combines them once again into water while delivering an electric …

MIT Solar Findings Mirror Those of 13 Year Old’s Tree Research

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

A recent report from MIT, replete with computer algorithms and graduate level insights, made your editor dip back into a story about a young naturalist who saw a model in nature that could lead to more efficient solar arrays.  Both produced works of genius and give us hope for some real breakthroughs in solar power deployment. The Massachusetts Institute of Technology announced that, “Innovative 3-D designs from an MIT team can more than double the solar power generated from a given area,” and suggested that models of their new approach, “show power output ranging from double to more than 20 times that of fixed flat panels with the same base area.” Jeffrey Grossman, the Carl Richard Soderberg Career Development Associate Professor of Power Engineering at MIT and leader of the research team, reports in a paper published in the journal Energy and Environmental Science that the greatest improvements came in “locations far from the equator, in winter months and on cloudier …

Better Batteries: Wrap It in Seaweed

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

MIT’s Technology Review reported last September that researchers at the Georgia Institute of Technology and Clemson University had formulated a way to keep silicon anodes in lithium batteries from cracking under the strain of expending and contracting while they charge and discharge. They added a “binding agent and food additive derived from algae” that is in turn derived from seaweed. This enables the anode to charge and discharge at an eight times greater rate than an equivalent carbon anode without breaking down, a common problem for “raw” silicon. Environmentally friendly, the manufacturing processes for this type of anode are claimed to be clean and inexpensive. According to the Technology Review, “Lithium-ion batteries store energy by accumulating ions at the anode; during use, these ions migrate, via an electrolyte, to the cathode. The anodes are typically made by mixing an electroactive graphite powder with a polymer binder—typically polyvinylidene fluoride (PVDF)—dissolved in a solvent called NMP (N-Methylpyrrolidone). The resulting slurry is spread …

Matters of Note for the Green Flight Expo

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

One humanitarian business organization that will display at the Green Flight Expo following the completion of that seven-day event uses the type of technology the CAFE Foundation espouses for carrying medicines and supplies to remote parts of the third world that otherwise do not easily permit transport of any kind. Matternet’s slogan, “Lifting the Rising Billion” refers to those living primarily in Africa and is explained in their statement of belief.  “By increasing the access to reliable transportation for people living in poverty, we will enable them to find a sustainable path out of poverty. “We will connect people from geographically isolated communities to local and global markets through the Matternet.”  This credo applies to poor communities throughout the world, and Matternet is committed to creating airborne supply networks worldwide. Mechanisms are simple enough, with quadrotor helicopters, much like those used by Stanford Professor Sebastian Thrun and his alumni, Nicholas Roy (now assistant professor at MIT) in their investigations of …

Cambridge Crude and Range Euphoria

Dean Sigler Electric Powerplants 1 Comment

Massachusetts Institute of Technology (MIT) scientists have announced what they claim is a “Significant advance in battery architecture [that] could be breakthrough for electric vehicles and grid storage.”    According to a story by David L. Chandler from the MIT News Office, the new battery system is lightweight and inexpensive, and could make recharging “as quick and easy as pumping gas into a conventional car.” Seemingly requiring some active components within the battery, this “semi-solid flow cell” pumps solid particles suspended in a carrier liquid which form the cathodes and anodes through the system.  According to the MIT news item, “These two different suspensions are pumped through systems separated by a filter, such as a thin porous membrane.”  Mechanically more complex than today’s batteries, the system still has a claimed “10-fold improvement over present liquid-flow batteries” (not necessarily that much better than lithium ion, then), but lower manufacturing costs. The different fluids are contained in two different containers and not …

A Pair of Viruses Good for Your Computer – and Maybe Your Electric Vehicle

Dean Sigler Electric Powerplants Leave a Comment

To say that your battery is “smoking” would normally be the sign of a failed circuit, but researchers at the A. James Clark School of Engineering and College of Agriculture and Natural Resources at the University of Maryland may be putting a virus that’s bad even for tobacco to good use in creating a battery that may be up to 10 times more powerful than today’s best lithium cells.   Professor Reza Ghodssi, director of the Institute for Systems Research and Herbert Rabin Professor of Electrical and Computer Engineering at the Clark School,  is “harnessing and exploiting the ‘self-renewing’ and ‘self-assembling’ properties” of the  Tobacco Mosaic Virus (TMV), which in its unrestrained natural state destroys tobacco, tomatoes, peppers and other leafy green things.   The idea that battery creation is a self-directing event is belied by the University’s video. Scientists found, “They can modify the TMV rods to bind perpendicularly to the metallic surface of a battery electrode and arrange the rods in intricate and orderly …

A Sweet Look Into the Future

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Zach Hoisington, an engineer with Boeing Research and Development, proposes an electric airliner concept through the Subsonic Ultra Green Aircraft Research (SUGAR) program.   During the CAFE Foundation’s fourth annual Electric Aircraft Symposium in Rohnert Park, California in April this year, he shared an amazing array of alternatives.   Making airliners viable in an era of disappearing fossil fuel has caused NASA and aircraft producers to explore different design approaches, including joined wing aircraft, strut-braced wings, and hybrid wing-body configurations. Strategies for doing more with less may include aerial refueling for extended range flight with larger payloads, and formation flights on common routes like those of migrating birds to reduce induced drag.  New sources of power may include hydrogen fuel cells and podded or integral batteries. Although the last option filled most of the talk, it came with the caveat that given current levels of battery development, it would take 5.5 million pounds of cells to produce the same energy derived from 60,200 pounds of …

The Light at the End of the Funnel

Dean Sigler Electric Powerplants Leave a Comment

In some exciting news that could make several quantum leaps in solar cell performance, Massachusetts Institute of Technology researchers have announced a hundred-fold increase in light gathering capabilities for solar cells. If a cell were able to exploit this increase, an aircraft such as the Solar Impulse could fly on 120 solar cells instead of the 12,000 now spread across its over 200-foot wingspan. We’ve reported on carpet-like light-capturing formats for increasing solar cell output, but the MIT approach funnels light down a multi-carbon nanotube filament, boosting the output of the “tiny” solar cell at the bottom. MIT’s press release explains the outcome. “’Instead of having your whole roof be a photovoltaic cell, you could have little spots that were tiny photovoltaic cells, with antennas that would drive photons into them,’ says Michael Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering and leader of the research team. “Strano and his students describe their new carbon nanotube antenna, …