Archive for March, 2012



15
Mar
12

sonic illusions from ancient civilizations

Post from Alan Brown:

When Lincoln Center concert hall opened in 1962, not everyone loved the sound. It took nearly 40 years and numerous minor and two major renovations to create the right acoustic environment for the New York Philharmonic Orchestra.

This story helped me put the accomplishments of ancient civilizations into perspective.

While attending the annual meeting of the American Association for the Advancement of Science (AAAS) in Vancouver, I stepped into a session on archeoacoustics—the study of acoustics in ancient structures—that left me spellbound. It turned out that past civilizations could teach us a lot about sound.

Humanity’s connection with sound traces back to our deepest roots. Paleolithic cave artwork is most often found in caves with the greatest echoes, where small groups of people might have bonded while playing music, singing, and dancing. Similarly, artwork along canyons, such as Utah’s Horseshoe Canyon, occurs in places with greatest echoes.

Archeology’s focus on the physical world blinded past generations of researchers to the sonic quality of the ruins they were investigating.

Not any more.

Take, for example, the sonic illusions at the 1,000-year-old Mayan ceremonial complex at Chichen Itza, a few hours south of Cancun. The main pyramid features 91 steps. If you stand in front and clap your hands, the stairs scatter the sound and reflect it back, with each step having a slightly different time delay. Instead of the sharp clapping sound we expect, it comes back as a chirping sound.

Researcher David Lubman claims the chirps are similar to those of the quetzal, a sacred bird of the Maya. (Click here to listen to two quetzal chirps followed by two handclaps.)

The nearby ball court, about the size of two football fields, is bound on opposite sides by two small temples. They form a whispering court that lets a person in one listen to a conversation in the other. They also let speakers project words onto the playing field, or sound like a whooping bird flying left to right.

In the Peruvian Andes, 1,500 years earlier, the Chavin people built a ceremonial building that also played sonic tricks. One example, according to Stanford University graduate student Miriam Kolar, is the waterway under the stairs leading to the entrance. Pouring water into the channel creates a sound like thunder.

Building itself is a complicated maze of hallways, vents, and chambers. The surprise is that they all work together to amplify sound and direct it towards three openings in the front. Think of it as the ancient equivalent of a bass reflex speaker.

She tested her theory by having musicians play two conch sell trumpets. She said the sound felt like it was coming out of the floor, and vibrated her whole body.

How did they learn to do this? No one knows. Perhaps it was all trial and error. But like Lincoln Center, they eventually got it right.

14
Mar
12

free heat transfer webinar

On Wednesday, March 28, Mechanical Engineering magazine will be having a free webinar, Conjugate Heat Transfer with COMSOL Multiphysics. If you’re invovled with heat transfer, and are interested in tuning in, you can register by clicking here.

14
Mar
12

In the air again

Post from Harry Hutchinson:

My head’s in the clouds. That’s because the rest of me is going to be up there in a few days: I’m going to be traveling again.

There is something unique about being in a place, almost any place. Sure, the Internet has brought the world to our computer screens—or at least, many and various interpretations of the world.

But it isn’t the same as sitting in your hotel in Chiang Mai and hearing the monks chant next door, or having the pork knuckle and black ale at U Fleku in Prague, or watching “As You Like It” at the New Globe in London.

This time, I’ll be flying out of Newark, changing planes and sampling beers in Atlanta, and then pushing on to Sarasota. My destination is a small island that separates Tampa Bay from the Gulf of Mexico. When I get there, I’ll take my tie off, sit in the kayak, and shake fins with the dolphins.

I’m going primitive, right? When I’m on dry land, I’ll be taking photos with a digital camera, speaking asides into a digital voice recorder, updating my friends by e-mail (on a Macintosh notebook computer), and riding a bicycle.

Well, the bicycle sounds a little on the primitive side, yes, but if you caught Frank Wicks’s article “Credit to the Bicycle” in the July 2010 issue of Mechanical Engineering, you were reminded that a bike is a pretty sophisticated instrument. It spurred the refinement of bearings and other mechanical advances that led to later developments. It laid the manufacturing groundwork for the automobile.

To get to the island, I’ll drive my car to the airport, take a shuttle to the terminal, fly on two jet aircraft, and be met at the airport by my sister and brother-in-law in a late model SUV. In a matter of hours, I’m going to cover more than a thousand miles in the air and more distance than a day’s walk—close to 40 miles—on the ground. The jets are likely to be single-aisle narrow-body airplanes, which right now are a source of prosperity for gas turbine manufacturers. You can get more on that in the May issue, which will include Lee Langston’s report on the state of the turbine industry, “Breaking the Barriers.”

I’ll follow the same path in reverse on the way back.

I have a passion for travel. I get to see places that I only dreamed about when I was a kid. It’s time again to say thanks to all the inventors, builders, and others who make it possible.

13
Mar
12

Improving on DIY Wind Power

Post from Jeffrey Winters:

If you spend enough time digging around hobbyist and do-it-yourself websites–guilty as charged–you’ll inevitably run across dirt simple plans for building a vertical-axis wind turbine. Many of those plans tout the ability of the VAWT to turn in very low winds. That makes for a nice display, but it winds up being fairly worthless for capturing energy, since the power of the wind is proportional to the cube of the velocity. Half the speed means one-eighth the power.

The other problem is that while building a Savonius rotor is easy–basically, it’s a pair of half cylinders mounted on an axis–its efficiency is low. That’s because while the wind produces torque pushing on the concave side of one half-cylinder, it’s cancelling some of that torque by also pushing on the convex side of the other cylinder.

There are, as you might imagine, DIY solutions to that problem, and two of them were tested late last year in ASME’s Journal of Solar Energy Engineering. Binyet Emmanuel and Wang Jun of the Fluid Machinery Department of Huazhong University of Science and Technology in Wuhan used CFD modeling to test whether tripling the number of blades or placing a cowling or vanes around the rotating blades would cut down on negative torque and increase the turbine’s coefficient of power.

The results were interesting. The six-bladed Savonius rotor performed only marginally better than the traditional two-bladed one, maxing out at 30 percent efficiency rather than 25 percent. But by adding fixed vanes that funnel the wind into the concave side of the rotors, maximum efficiency jumped to nearly 50 percent.

The researchers cautioned that real-world efficiencies would be a little lower, but it’s gratifying to see that some of those backwoods engineers crafting gear from plywood and sheet aluminum might be onto something.

12
Mar
12

Japan’s Energy Conundrum

Post from Jean Thilmany:

This past weekend, many news outlets marked the one-year anniversary of the Japanese 2011 earthquake and tsunami that caused great damage to the country and 19,000 deaths, and that destabilized the Fukushima Daiichi nuclear plant.

With one year’s distance, the news outlets have checked in also with the state of Japan’s power industries. In an attempt to meet climate change goals set under the Kyoto Protocol, Japan had planned to increase nuclear power capacity to more than half of its total electricity requirement by 2030.

But with the earthquake, all that has changed.

A story on National Public Radio on March 10 reported that, according to an analysis by the International Energy Agency, replacing the electricity from idled nuclear plants is costing Japan an extra $100 million a day. Then there are the climate effects. The nuclear reactors were not emitting carbon dioxide, the main greenhouse gas. Oil, coal, and natural gas do.

Japan’s goal to reduce carbon dioxide emissions is now shelved. In fact, emissions are going up, Jesse Jenkins, an energy analyst at a research group called the Breakthrough Institute, told NPR. That’s because Japan is swapping fossil fuels for nuclear and that’s driving up their CO2 emissions and the carbon intensity of their electricity supply.

Most of the new fuel is liquefied natural gas. It’s cleaner than coal or oil, but Laszlo Varro, with the International Energy Agency, said Japan would need almost 20 percent of the entire global market of liquefied natural gas if it doesn’t return to nuclear power.

But buried amid the report—indeed little highlighted in any new commemoration of the earthquake, but there reported nonetheless—is this tidbit: The Japanese government has expressed a strong sentiment to adopt a new energy mix that relies mostly on wind and solar power.

That will take decades, though. Renewable energy in Japan now provides about 2 percent of the nation’s electricity; nuclear provided 30 percent. Still, there’s a great deal of hope for success. Last month, Japan’s environment ministry announced plans to allow power generation by extracting geothermal heat from the nation’s national parks.

According to the NPR report, Japanese engineers are second to none. American engineers may resent the hubris. But as Japan begins its recovery and starts turning its attention toward renewable energy sources, engineers around the globe may begin sharing strategies and projects to move all nations toward renewable sources.

And Americans, who will need to rely more on renewable energy themselves in the near future, can only benefit as Japanese engineers pour their own energies into investigating new technologies that will allow them to source these projects.

09
Mar
12

Video: asme human powered vehicle challenge

The ASME Human Powered Vehicle Challenge provides an opportunity for undergraduate and graduate engineering students to demonstrate the application of sound engineering design principles in the development of sustainable and practical transportation alternatives.

Click here to see video

08
Mar
12

Secret Agent Drones

 Post from Jeffrey Winters

In April 2011, Brandon Basso of the University of California and his colleagues wrote “Airborne, Autonomous & Collaborative,” a cover article about the possibilities of collaborative swarms of UAVs. “With UAVs becoming both cheap and easy to build,” they wrote, “the field’s leading edge is now systems—squadrons of two or five or ten aircraft, collaborating to achieve a common goal. The ambition is to use teams of flying robots to develop vision-based maps of large areas, track moving objects, fuse information from multiple aircraft and multiple sensors, and perform high-level task planning.”

And that is still the long-term goal, I’m sure. But the ability to link up small quadrotors—pint-sized helicopters that have the ability to hover in mid-air as well as fly in any direction—has led researchers and hobbyists alike to use these minidrones for seemingly more frivolous activities. The video found by clicking here may seem like a stunt, but as the University of Pennsylvania’s Evan Lerner writes, “Lab members… assign each unit a series of waypoints in three-dimensional space that must be reached at an exact time…. Figuring out how to get from waypoint to waypoint most efficiently and without disturbing their neighbors is up to the robots.”

Building up expertise in swarm navigation will lead to all sorts of advances. One can imagine a swarm of mini-UAVs going house to house looking for enemy soldiers—or searching the countryside for missing children. But before we get to such serious work, these flying robots must first learn how to play.

07
Mar
12

does technology make great ideas?

The following is the first post by guest blogger Alan Brown, associate editor at Mechanical Engineering magazine. Look for his posts weekly.

Alan Brown

My guess is that most of us have heard Victor Hugo’s famous quote, “There is nothing as powerful as an idea whose time has come.” But doesn’t technology set the stage for many of those ideas?

I started speculating about this last week when I attended the Science Writers in New York annual party. At one point, I found myself talking to another writer about what makes people happy.

“If a woman wants a happy marriage,” she said, “she should marry a man who
will take her name.”

That was a challenging statement, and soon led to a discussion about how much the women’s movement really changed society. In her view, it hasn’t been that much. From my perspective (which probably included about 15 or 20 years of additional personal experience), quite a bit.

Afterwards, I started musing about why some changes take so long to take hold, while others percolate through society so quickly. What really struck me was how many were technological in nature.

While some will argue that personal computers changed the world, I think the real game-changer was the Internet. From America Online to Google and now Facebook and YouTube, it altered how we communicate, learn, shop, and interact with one another.

The Internet put the world on a 24/7 cycle. It nearly wiped out the music industry and changed how we learn about new products and new ideas. As Thomas Friedman has pointed out, it leveled the playing field. Today, anyone anywhere with an Internet connection, a thirst for knowledge, a good idea, or an innovative product can be part of the global marketplace.

Smartphones, which made the Internet portable, ushered in the third revolution of my lifetime. It is easy to argue that putting the Internet in our pocket is merely an extension of what has come before. But I think it changes how we do things in fundamental ways, whether it is learn the news, keep in touch with friends, read a book, watch a movie, or overthrow a dictatorial regime in the Middle East. This is a revolution that is only a few years old, yet I see profound changes in how people interact with one another, and in their expectations about privacy, friendship, and the ability to learn what they need to know (from train schedules to restaurant ratings to the score of your home team’s basketball
game) in an instant.

Before my lifetime, there were other massive changes. I would put the automobile first, followed by mass media (radio/TV/television) and airplanes.
 
I mentioned some of this to a fellow editor, and she suggested I add sewing machines to my list. I can see why. They made the ready-to-wear industry possible and freed women from the drudgery of making their own clothing. This gave them time to do others things, including moving into the public sphere in ways that would have been impossible 150 years ago.

So now I’m curious: Do you buy my thesis? I know that I have only sketched out my thoughts, but I believe technology sets the scene for Hugo’s powerful ideas.

Do you agree with my technology choices?

Have others you would add to the list?

06
Mar
12

The Kids Clean Up Again

Post from Harry Hutchinson:

One of my favorite teams was back in the news a short while ago. The Kell High School Robotics Team had been invited to the White House Science Fair to exhibit the students’ latest invention, a remote-controlled device for skimming oil from the surface of shallow waters. Kell High is in Marietta, Ga., and a local Fox affiliate, Channel 5 in Atlanta, picked up the story.

The group had designed the remotely operated vehicle as a Lemelson-MIT Inventeam project. According to the team, the design is a response to the Deepwater Horizon oil spill. It has a conveyor system to transfer oil into a containment unit, a tread system to negotiate hazards in shallow waters, and solar panels to extend battery life. A GPS unit and camera help with navigation.

They call the device ORCA, for “oil recovery and capture.” The design landed a $10,000 Inventeam grant. The team took a one-third scale model first to EurekaFest at Massachusetts Institute of Technology, and then on to the White House Science Fair.  

The Kell team started as a competitor in the FIRST Robotics Competition, but caught the inventive bug in a bigger way. An earlier invention by the group was Corky, an ROV designed to pick up floating trash and litter from lakes and streams. Mechanical Engineering magazine carried a story about that one in the January 2010 issue. It made use of parts from old robotics kits left over from earlier FIRST seasons.

Corky went on to win a SeaWorld/Busch Gardens Environmental Excellence Award that netted the team a prize of 10 grand and a trip to Busch Gardens in Tampa Bay.

This doesn’t take anything away from kids who play ball. I tried and never got the hang of it. Too clumsy, too slow. But wow. These are kids who build robots. They work with engineers, teachers, grad students, and just about anyone else who can make a contribution. Talk about widening your horizons.

Their website, which has some elements under construction, contains some pretty sophisticated video, but better than that is the line that introduces them all: “We are the people who sit at the ‘cool table.’”

But why should anybody be surprised by that? After all, isn’t that what FIRST hopes to do for kids everywhere?

RuthAnn Bigley, who works for ASME in Georgia, keeps us in the New York office up to date on the Kell team’s doings.

05
Mar
12

become a celebrity engineer

The following is the first post by guest blogger Jean Thilmany, associate editor at Mechanical Engineering magazine. Look for her posts weekly.

Jean Thilmany

We’ve received an announcement here at Mechanical Engineering magazine that the casting crew for a new Discovery Channel reality show tentatively titled Top Engineer is looking for designers who can build, machinists who can design, and the like.

To my way of thinking, it’s about time engineers got a chance at the prime time (not that a cable TV show is exactly prime time. I get that.). Decades ago, the Indiana Jones movies portrayed a dorky professor who spent his not-so-off hours cracking whips in distant locales and racing through mines while outsmarting evil villains, all in a bid to recover important artifacts.

A slew of recent cable television shows, including MythBusters and even shows like Curiosity (which purports to answer pressing scientific questions like why is sex fun) presents engineering pursuits as interesting and valid, worthy of investigation by a crew from Hollywood. Far cry from the Dilbert cartoons of years past.

But I admit my thinking along these lines can diverge. When Mike Rowe, host of Dirty Jobs (also on Discovery Channel) spoke at the SolidWorks users conference last month in San Diego, I felt he stood out from the crowd, mostly due to his gym-toned body, his California tan, and his confessed-to long time interest in getting into show business. Rowe isn’t an engineer, but he can come into contact with them on his show.

Most engineers, like almost everyone, toil in obscurity, many at jobs they find challenging and fun. And many put their working hours and free time to use by calling upon their engineering skills to help others. See the Engineering for Change website for proof of that.

While Engineering for Change and programs like the FIRST Robotics Competition are good ways to reach out to kids who may be interested in engineering, television programs like Top Engineer may help get the job done too. After all, I majored in journalism at a time when programs were stuffed to the gills because of the popularity of the movie and book All the President’s Men. I believe L.A. Law had a similar effect on law schools for a while.

And while I know engineers without traditionally keen good looks or a controversial personality are unlikely to make the Top Engineer cut, at least popular culture is starting to reflect back the truth: engineers are smart, sociable characters who do challenging and interesting work.




The Editor

John G. Falcioni is Editor-in-Chief of Mechanical Engineering magazine, the flagship publication of the American Society of Mechanical Engineers.

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