Category Archives: Engineering

Statistics for Experimenters Review

Disclosure, I am a bit biased – William G. Hunter was my father. But I agree with this review of Statistics for Experimenters: Design, Innovation, and Discovery , 2nd Edition posted by George Samaras

Superb! If you are involved, in any way, with science or engineering, you need this book on your shelf (after you have carefully read it twice). My only complaint is that I found out about it circuitously reading Prof. Box’s “Improving Almost Anything”; I was curious what the often cited BHH reference was. I think someone should have a word with the publisher’s marketing department; if we don’t know about it, how are we supposed to buy it?

George Box, Stu Hunter and Bill Hunter authored the first edition book in 1978 and the second edition in 2005.

I maintain Statistics for Experimenters web site. Visit the page to find resources, or to let us know about resources (data sets, exercises, etc.) for those using the book.

The Loop Stitch

The how stuff works site does a great job of providing interesting explanations of. un-surprisingly, how things work. The design of of the web site is less good, in my opinion – way to much non-content (the content fills up maybe 15% of my screen on this link for example (once I scroll down it might improve to about 30% content): The Loop Stitch:

The most important element of a lock-stitch mechanism is the shuttle hook and bobbin assembly. The bobbin is just a spool of thread positioned underneath the fabric. It sits in the middle of a shuttle, which is rotated by the machine’s motor in synch with the motion of the needle.

Just as in a chain-stitch machine, the needle pulls a loop of thread through the fabric, rises again as the feed dogs move the fabric along, and then pushes another loop in. But instead of joining the different loops together, the stitching mechanism joins them to another length of thread that unspools from the bobbin.

When the needle pushes a loop through the thread, the rotary shuttle grips the loop with a hook. As the shuttle rotates, it pulls the loop around the thread coming from the bobbin. This makes for a very sturdy stitch.

See the site for a graphic that does a much better job of making it clear, how it works, I think.

Rubick’s Cube Solving Lego Mindstorms Robot

Lego Mindstorms have really really provided some great tools for home robot engineering. JP Brown has several examples on his web site including this CubeSolver:

The longest part of the this project involved writing the color-recognition software. I downloaded the Logitech Quick Cam SDK from the Logitech Developer’s site (the LEGO Vision Cam is a repackaged Logitech Quick Cam) and used VB5 to write a fairly decent program (click the Code link for source). The color recognition is fairly robust (about one error every two cubes when well-calibrated), but not perfect, so I incorporated a feature that requires you to confirm that each face has been correctly scanned (and, optionally, allows you to correct the input manually) before it scans the next face.
…
My early attempts at building a cube solver were all stymied by grips that slipped. The worm-56t gave enough torque to turn, but the fingers couldn’t hang on and the grip was simply pried apart as the grabber rotated around the stationary cube face. I thought about changing the device’s name to ButterFingers.

I rebuilt the left and right grabbers six times (and the bottom grabber four times) trying elastic bands, Technic shocks, and pneumatics, before I came up with an adequate grip mechanism. In the present version, an axle runs from a motor through the center of the large Technic turntable to a worm screw. The worm screw turns two 24t gears mounted either side of the worm inside the body of the grabber.

Other home engineering favorites: Awesome Cat Cam – Windmill for Electricity – Lego Autopilot First Flight

Super Soaker Inventor Aims to Cut Solar Costs in Half

[Lonnie ] Johnson, a nuclear engineer who holds more than 100 patents, calls his invention the Johnson Thermoelectric Energy Conversion System, or JTEC for short. This is not PV technology, in which semiconducting silicon converts light into electricity. And unlike a Stirling engine, in which pistons are powered by the expansion and compression of a contained gas, there are no moving parts in the JTEC. It’s sort of like a fuel cell: JTEC circulates hydrogen between two membrane-electrode assemblies (MEA). Unlike a fuel cell, however, JTEC is a closed system. No external hydrogen source. No oxygen input. No wastewater output. Other than a jolt of electricity that acts like the ignition spark in an internal-combustion engine, the only input is heat.

Here’s how it works: One MEA stack is coupled to a high- temperature heat source (such as solar heat concentrated by mirrors), and the other to a low-temperature heat sink (ambient air). The low-temperature stack acts as the compressor stage while the high-temperature stack functions as the power stage. Once the cycle is started by the electrical jolt, the resulting pressure differential produces voltage across each of the MEA stacks. The higher voltage at the high-temperature stack forces the low-temperature stack to pump hydrogen from low pressure to high pressure, maintaining the pressure differential. Meanwhile hydrogen passing through the high-temperature stack generates power.

“It’s like a conventional heat engine,” explains Paul Werbos, program director at the National Science Foundation, which has provided funding for JTEC. “It still uses temperature differences to create pressure gradients. Only instead of using those pressure gradients to move an axle or wheel, he’s using them to force ions through a membrane. It’s a totally new way of generating electricity from heat.”

Very cool and yet another example of the benefits of educated engineers. The positive externalities are large for engineering education.

Really Widescreen Monitor (2880×900)

I foolishly bought a 22 inch “widescreen” monitor (I guess I can’t call it that now) last week. What was I thinking? Seriously the video shows a 2880×900 curved monitor from Alienware is scheduled to be released in the second half of this year. No price estimate is available yet. It is actually a rear projection DLP system. Last year, in Two Screens Are Better Than One we showed a Microsoft prototype very similar to this.

UbuntuScience

UbuntuScience is a great source of information on hundreds of freeware and open source science software for the unbuntu operating system (linux), including:

KStars – A virtual planetarium
Coot – Superb tool for crystallographers
R – for statistical computing and graphics
LaTeX – text mark up system used by scientists in several fields (e.g., physics, mathematics) to write papers
BOINC – A software platform for distributed computing using volunteered computer resources. Projects include: Climateprediction.net, Einstein@Home, LHC@home, Predictor@home and SETI@home.

Science and Engineering Education Collaboration in Virginia

Two new schools to focus on technology

Two new schools focused on career, technology and engineering for high school and college students will open in Newport News and Suffolk. But while the Suffolk school will have a home in the Pruden Center for Industry, the other will look more like a network, reaching out from a base at the New Horizons Regional Education Center into six school districts, two colleges, at least one government agency and several area businesses.
…
The Newport News academy is aimed at high school students and will focus on electrical and mechanical engineering, Johnson said. Students will follow the curriculum requirements for an associate of arts degree available at academy partner Thomas Nelson Community College, which can lead to a bachelor’s degree at another partner, Old Dominion University. Russo said emphasis will include robotics, modeling and simulation technology and engineering.

Instead of housing the school at New Horizons or Thomas Nelson, the academy’s classes will be taught in public high schools in Gloucester County, Newport News, Hampton, York County, Poquoson and Williamsburg-James City County, at New Horizons and at Thomas Nelson. Additional courses will be available online.

Robot Fly

Tinker, Tailor, Robot, Fly

Designing an automated fly implied having the ability to make lightweight, miniature working parts, a process that Wood says took up the bulk of his doctoral study, because of the lack of any previous research on which to draw. “For years, the thrust of our work was ‘How do we do this?'” says Wood. “There was no existing fabrication paradigm, given the scale we were operating on, the speed we wanted to operate with, and things like cost, turnaround, and robustness.” His research group developed and fabricated a laser carving system that could meticulously cut, shape, and bend sheets of carbon fiber and polymer – both strong but lightweight materials – into the necessary microparts.

And how to power those wings to beat 120 times per second? To keep this 60-milligram robot (the weight of a few grains of rice) with a 3-centimeter wingspan to a minimal size and weight, Wood says, you can’t simply use a shrunken version of the heavy DC (direct current) motors used in most robots. So he and his team settled on a simple actuator: in this case, a layered composite that bends when electricity is applied, thereby powering a micro-scale gearbox hooked up to the wings. Wood says the actuator works even better than its biological inspiration. The power density – a measure of power output as a function of mass – of a fly’s wing muscles is around 80 watts per kilogram; Wood’s wing design produces more than 400 watts per kilogram.

The first takeoff occurred late one evening last March, as Wood worked alone in his office, his colleagues gone for the evening. As the fly rose, Wood jumped up in celebration, quickly verified that his camera had captured the flight, and let out a sigh of relief.

LEGO Project Inspires Students

LEGO project inspires students

After school every Thursday at New Haven Elementary more than 60 students gather to discuss energy sources, plan building models, and learn more about science and engineering. The group, made up of first-, second- and third-graders, is participating in Junior First LEGO League (JFLL). JFLL is a worldwide organization that introduces children to concepts of teamwork and basic design skills.

Karen Cheser, elementary director of teaching and learning for Boone County Schools, brought the program to the district. It relies on 10 volunteer coaches including school teachers, a robotics engineer, parents, and business owners to guide students.
…
“Participation is very active because of the hands-on component of the work,” Fortner said. “Students see it as a club, but we look at it as an extension of the school day, because it teaches fundamental science concepts, it encourages teamwork, and builds social skills.”

The First Lego League web site provides information on local programs all over the world.

Africa Turning to China and India for Engineering and Science Education

‘Browning’ the technology of Africa by G. Pascal Zachary

The sudden influx of Chinese and Indian technologies represents the “browning” of African technology, which has long been the domain of “white” Americans and Europeans who want to apply their saving hand to African problems.

“It is a tectonic shift to the East with shattering implications,” says Calestous Juma, a Kenyan professor at Harvard University who advises the African Union on technology policy. One big change is in education. There are roughly 2,000 African students in China, most of whom are pursuing engineering and science courses. According to Juma, that number is expected to double over the next two years, making China “Africa’s leading destination for science and engineering education.”

China’s technology inroads are usually less dramatic, but no less telling. In African medicine, Chinese herbs and pharmaceuticals are quietly gaining share. For example, the Chinese-made anti-malarial drug artesunate has become part of the standard treatment within just a few years. Likewise, Chinese mastery over ultra-small, cheap “micro-hydro” dams, which can generate tiny amounts of electricity from mere trickles of water, appeals to power-short, river-rich Africans. Tens of thousands of micro-hydro systems operate in China, and nearly none in Africa.