@Ann: Although steel is stronger than aluminum, it's not really too surprising that forged aluminum wheels are stronger than steel wheels made from sheet metal -- the designs and manufacturing processes are completely different. A forged steel wheel would be much stronger than a forged aluminum wheel, but would also weigh a lot more. (Forged steel wheels make sense for railroad cars, but definitely not for on-road applications).
The lifecycle analysis is very interesting. It is very comprehensive, and all of the assumptions seem to be reasonable. It makes a convincing case.
Lou, you're certainly right about the recyclability of aluminum, and steel too to a somewhat lesser extent. But it's also true that LCA has to look at everything. In fact, the latest concept of the life cycle is "cradle-to-cradle", not "cradle-to-grave." CtoC includes that last link in the chain that closes the loop (to mix metaphors) of recycled material going back into the product.
Ann, you mention end of life phases when talking about the life cycle cost analysis. You mention recycling and disposal. Steel and aluminum of this type will certainly be recycled. It has been known for some time that aluminum recycling is extremely effecient. I think it uses about 5% of the energy to recycle aluminum as it does to refine it from bauxite. Steel is also effecient, although I am not sure of the ratio. Steel mini-mills are the most effecient steel mills becuase they use scrap. So, I assume in this case the wheels of both types will be recycled.
It is good, though to see such comprehensive analysis. If you are looking at full lifecycle costs, then you really have to look at everything.
The company that brought you 3D-printed eyeglasses has launched both an improved clear polymer material for 3D printing optical components and a high-speed, precision, 3D-printing process for making small- and medium-sized batches in a few days.
We've found an amazing variety of robot hands & arms in medicine, space, and service robots, as well as R&D and assembly. Some are based on industrial designs modified for speed or dexterity, while others more closely emulate human movements, as well as human size and shape.
To give engineers a better idea of the range of resins and polymers available as alternatives to other materials, this Technology Roundup presents several articles on engineering plastics that can do the job.
The first photos made with a 3D-printed telescope are here and they're not as fuzzy as you might expect. A team from the University of Sheffield beat NASA to the goal. The photos of the Moon were made with a reflecting telescope that cost the research team £100 to make (about $161 US).
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.