Category Archives: Engineering

Gecko’s stick inspires adhesives and even superheroes

November 9th, 2012

By Ashley Yeager

A single hair on a gecko’s foot has enough “stickiness” to pick up an ant. Credit: Kellar Autumn, Lewis & Clark College.

Sticky feet driving you up the wall?

Well, maybe not. But they are for Cicak, or Gecko-Man. After a few sips of coffee contaminated by a virus-infected gecko, a loser lab scientist suddenly becomes a Malaysian superhero, sticking to walls, using his tongue to scale skyscrapers and even eating bugs.

“Gecko feet are nature’s best adhesion and removal device,” said Lewis & Clark College biologist Kellar Autumn. He gave the keynote speech during the awards ceremony of the third annual Abhijit Mahato photo contest on Nov. 7.

While Autumn riled up the audience with his images and videos of the science behind gecko feet and their inspiration for new adhesives, robots and superheroes, he also used the talk to remind the photographers in the audience that appearance and scientific images can be misleading.

The science of how geckos climb up walls and across ceilings is at least a 200-year-old question, one that even Aristotle tried to answer. In the late 1960s, one scientist took some scanning electron microscope images of gecko feet and thought they revealed suction cups as the mechanism that let geckos scale walls and ceilings. But that idea was wrong.

It wasn’t until Autumn and his collaborators began looking more closely at the creature’s feet in the late nineties and early 2000s that scientists realized it wasn’t suction, but nanometer-scale interactions between a surface and the gecko’s foot hairs, or setae, that let them stick, release and climb. His team took a single gecko foot hair and made the first direct measurement of its adhesive function. Turns out the stickiness in one hair is so strong it can lift the weight of an ant.

The team also discovered that geckos release their feet as they climb by changing the angle of their feet hairs. That means that the contact geometry of setae are more important that any other factor in their ability to climb, Autumn said, adding that the discovery demonstrated “we could make this stuff.”

Tom Cruise climbs a skyscraper with “gecko gloves: in MI:Ghost Protocol. Image courtesy of: Danny Baram.

He showed videos of both the kinematics and kinetics of the way geckos climb and compared and contrasted the physics the creatures use to the human-engineered “nanopimples” and wedge-shaped nanoridges that resemble geckos’ sticky feet. The animal’s foot physics is “different than pretty much everything else out there,” Autumn said, though he did describe several developing projects to try to mimic the animals’ movements.

Still, he said, he’s convinced that “had geckos not evolved their sticky feet, humans would not have invented adhesive nanostructures.” And, there’s no way we’d have gecko gloves or could even think of gecko band-aides and the other cool applications of gecko-feet science, he said.

Citations:

“Adhesive force of a single gecko foot-hair.” Autumn, K., et. al. (2000). Nature 405, 681-685.

“Evidence for van der Waals adhesion in gecko setae.” Autumn, K., et. al. (2002). Proc. Natl. Acad. Sci. USA 99, 12252-12256.

“Evidence for self-cleaning in gecko setae.” Hansen, W. and Autumn, K. (2005). Proc. Nat. Acad. Sci. U. S. A. 102, 385-389.

Student Cameron Kim, Working to Reprogram Cells

October 8th, 2012

By Nonie Arora

Meet Cameron Kim – a Pratt Engineering student working on synthetic biology who also officiates for the Duke Quidditch team. Originally from Brandon, Florida, Cameron became interested in molecular biology and engineering in high school.

Kim Observing His DNA Gel Credit: Cameron Kim

“I see most people identify biomedical engineering as biomechanics, neural engineering, and electrophysiology,” he says, “but there’s really this other side growing quicker and quicker, which is using the tools of molecular biology to control how we as humans function and interact with the environment.”

In Dr. Charles Gersbach’s lab, he has been working to create artificial transcription factors. Being able to control gene expression through transcriptional factors is vital to modulate cell behavior and human functions, Kim says.

Kim drew an analogy between a transcription factor and a light switch dimmer, saying that transcription factors allow for a range when turning on and off specific genes. He says that artificial transcription factors would allow him to influence a cell’s own genome without having to add extra copies of a gene. The goal is to develop a tool to reprogram cells that his lab can use to study muscle development and to hopefully repair muscles. His lab is looking at different ways to develop therapies for Duchenne muscular dystrophy.

Kim thinks that engineering design principles that he has learned through his Pratt coursework are really important to his project. “When I explain my research to a lot of people, they think I’m just doing molecular biology,” he says, “but by knowing the parts and understanding my materials, I can design biological molecules and tools do what I want them to do.” While we may traditionally associate engineers observing factors like the terrain or landscape to build a bridge, he looks at factors like energy barriers and cell functions to apply design principles to molecular biology.

Kim Presenting at the Howard Hughes Research Symposium Credit: Cameron Kim

Research is full of challenges, and Kim’s projects have been no exception. He says it has been challenging to develop his tool. While it looks great in one test, it does not work with another one. He is still investigating whether he should be looking for other factors to control or whether the challenges are due to biological limits.

When asked what advice he would give to other undergrads excited about delving into research, Kim said to recognize that “you’re not going to know everything and even brightest minds in the field don’t know everything,” and to also “find out more about whatever you’re interested and take advantage of wide base of knowledge around you.”

His project initially came out of the Howard Hughes Research Fellows Program, which he encourages first-year students to consider. Kim says, “An immersion program in research can be a just as exciting new environment as an immersion language program in another country.”

After Duke, Kim hopes to pursue medical research. He wants to ask questions like: “How can I bridge the gap from bench to bedside? What tools can I develop to reach a clinical applications?” He feels lucky to have been mentored by excellent scientists and would like to do the same for others in the future.

Third Mahato Viz Contest, Deadline Oct. 21

October 3rd, 2012

2011 People's Choice "Cold Atom Cloud," by Yinghi Zhang - Duke Graduate Student in Physics

Nearly 5 years after the tragic death of engineering graduate student Abhijit Mahato, the Duke community will once again honor his memory with a photography and visualization contest.

Deadline for entries is October 21, 2012. Rules are here: http://mahato.pratt.duke.edu/contest

This year’s awards ceremony and exhibit of entries will be Nov. 7 at 5 p.m. in Schiciano Auditorium. The keynote speaker at this year’s event will be Kellar Autumn, professor and chair of biology at Lewis & Clark College, who led a research team that discovered the trick gecko feet use to stick to any surface without an adhesive.

The first two contests produced a spectacular collection of beautiful images from scientific research to exotic locations to mundane objects like lightbulbs and jelly glasses viewed in startling new ways.

 

Learn More: http://mahato.pratt.duke.edu/

Reading between the lines of light

August 10th, 2012

By Ashley Yeager

Harry Potter's invisibility cloak is not exactly what scientists have in mind for their light tricks. Credit: Warner Brothers.

The way we understand light is largely based on how we see it. To our eyes, light is like a stream of particles.

Scientists usually study these particle streams by measuring their wavelengths and how they interact with objects. But over the last decade, researchers have begun to realize that light particles can interact with objects within wavelengths too.

Now, scientists are looking inside wavelengths to control and manipulate light, which is transforming the traditional field of optics, according to Duke engineer David Smith and his colleagues.

They describe the changes to the field of optics in a review article appearing online Aug. 2 in Science, and they describe how, at a tenth or even a hundredth of the wavelength of visible light, the classic picture of how we see breaks down.

In this regime, streams of light particles can bend away from an object, essentially tricking the eye into thinking the object is not there. As a result, scientists can no longer think of light in terms of particle streams. Instead, they must think of it as a manipulation of electric and magnetic field lines.

Thinking of light this way, Smith and other scientists are beginning to understand how they can hide one object within another and even harvest energy. The new understanding “will be the design tool of choice” as scientists continue to play with the forces between electrically charged particles, the authors argue.

Citation:

“Transformation Optics and Subwavelength Control of Light.” Pendry, J., et. al. 2012. Science 337: 549-552.
DOI: 10.1126/science.1220600

Friends in High Places

April 16th, 2012
tom katsouleas

Engineering Dean Tom Katsouleas has been instrumental in advancing the NAE's "Grand Challenges" strategy and establishing related programs at Duke and at USC.

Duke’s Pratt School of Engineering  earned a tip of the hat from one of the White House’s blogs recently.

The President is interested in pursuing a  ”grand challenges” strategy to identify big goals and inspire government agencies, universities, corporations, philanthropists, and presumably the general public, to pull together and tackle them.

In a post about the program last week,  Cristin Dorgelo and Tom Kalil  of the White House Office of Science and Technology Policy explicitly mentioned the Grand Challenge Scholars program at Duke as an example of how this approach can help.

Following on the National Academy of Engineering’s identification of 14 “Grand Challenges” in engineering, Duke introduced a special honors program for 20 students per year to identify and execute  a project related to one of the NAE challenges, culminating in a honors thesis at least, and perhaps a better world as well.

Fracking

April 11th, 2012

Source: Marcellus Effect

By Becca Bayham

You may wonder: what the frack is fracking?

Hydraulic fracturing, or fracking, is the process by which water, sand, and chemical additives are pumped into a well to fracture deep underground formations and allow natural gas to flow to the surface. Fracking has reduced our dependence on foreign oil, decreased carbon emissions and made significant contributions to our nation’s economy. However, the technology can have significant social and environmental impacts, according to Duke professor Avner Vengosh.

Vengosh joined Brooks Rainey Pearson from the Nicholas Institute, David Burnett from Texas A&M’s Global Petroleum Research Institute and Keith McLeroy from Texas’ Engineering Extension Service for an in-depth discussion about fracking, April 9. The event was sponsored by Environmental Alliance and the Drilling, Environment, and Economics Network, two on-campus student groups.

Vengosh described how shale gas drilling and fracking can disturb residents of formerly quiet towns with nearly-constant noise, odor and truck traffic.

“This is changing the dynamics of small towns in Pennsylvania [and other states] pretty significantly,” he said.

Vengosh said that fracking can also impact air and water quality — and thus human health. Earlier this year, he published the first peer-reviewed paper to examine well-water contamination from shale-gas drilling and hydrofracking. He and his colleagues found that drinking water wells within 1 km of a drilling operation were more likely to have high concentrations of methane, the primary component of natural gas.

Fracking is also very water-intensive, requiring millions of gallons of water at drilling each site. In areas experiencing drought conditions, this presents a serious problem, Vengosh said.

Many companies recycle the water they produce. However, the water that flows out differs significantly from water that went in, often containing high levels of salts, heavy metals and naturally-occurring radionuclides that can be difficult to remove. According to Vengosh, some companies bypass that difficulty by discharging their wastewater to nearby rivers or streams.

“It’s not nice, but it’s done,” he said.

According to Pearson, fracking exists within a unique regulatory environment. The technology is exempt from several national environmental policies that regulate hazardous waste disposal and environmental cleanup, among other things. Environmentalists often cite the so-called “Halliburton loophole,” which exempts fracking from the Safe Drinking Water Act.

Pearson insists that “these exclusions occurred over time — there’s no one bad guy.”

Many states include fracking under the umbrella of their existing oil and gas regulations, but those regulations aren’t necessarily sufficient, Pearson said.

“States are retroactively seeing the unique regulatory needs of shale gas production, such as the need for baseline water quality data.”

Baseline data — such as air and water quality information — is collected before drilling begins and allows researchers to assess the direct environmental impacts of fracking.

“Without baseline data, it’s very hard for regulatory agencies to say ‘the industry caused this contamination,’” Pearson said.

Burnett discussed efforts to “reach across the aisle between the environmentalists and the oilmen” to develop environmentally-friendly drill programs. The first step is measurement, he said.

“You’ve got to find out what you’re doing wrong, then you’ve got to fix it.”

The panel concluded by emphasizing that, for all its problems, natural gas will help us reduce our reliance on oil and coal and transition to an an era of cleaner energy.

“The effects are there, but you have to see the environmental impacts of the alternatives, which perhaps are worse,” Vengosh said.

April 17 — Goo, Goop, Gack (and Snot!)

April 10th, 2012

Gooey, goopy materials and a lecture about the wonders of snot are the stars of a family-friendly, hands-on evening of science on the Duke University campus  from 5–8 p.m. on Tuesday, April 17.

oobleck

A quivering mass of cornstarch "oobleck." Image by Collin Mel Cunningham via Flickr

The event will be in the Fitzpatrick CIEMAS building on Duke’s West Campus. Public parking is available in the Bryan Center structure on Research Drive, near the Duke Chapel.

Faculty and students will share experiences with oobleck cornstarch polymers, origami that folds itself magically, and  ‘soft matter,’ which is a polite term for other kinds of goopy stuff.

The evening also features tours of facilities including the DiVE virtual reality simulator, and a guest lecture, “The Science of Snot,” by Dr. Richard Superfine of UNC-Chapel Hill’s physics department.

All this edutaining fun is sponsored by The Materials Research Science and Engineering Center of the Research Triangle, a collaborative effort of Triangle universities funded by the National Science Foundation.  It’s also a part of the state wide North Carolina Science Festival being held April 13-29.

For more information on this event and the NC Science Festival, go to: http://www.ncsciencefestival.org/event/duke-goo/

Solving the world’s humanitarian problems

February 15th, 2012

By Becca Bayham

What will the world of 2050 look like?

Popular fiction tells us we’ll have hoverboards, spaceships and artificial intelligence. According to USAID advisor (and Duke alum) Alex Dehgan, we’ll also have new ways of addressing humanitarian challenges — and we’ll need them. Dehgan kicked off the Student International Discussion Group‘s Water & Energy Symposium, Feb. 10.

“We know that climate change is going to affect the U.S., the Middle East, Central Asia and North Africa. This is actually a national security issue for us,” Dehgan said. “One thing that I think has been forgotten is, it’s not just climate, it’s climate times the environment. It’s the interaction of these two pieces.”

Dehgan described a patch of tropical forest where all the trees had been cut down. Trees send moisture back to the atmosphere via transpiration. No trees, no rain. The ground dried up, and the area is now 30 degrees warmer than it was before.

The world of the future may look different in other ways. According to Dehgan, 51 countries will lose population between now and 2050, largely due to declining birth rates. Other countries such as India, Pakistan, Nigeria, Bangladesh, the Democratic Republic of the Congo, China, Uganda, Ethiopia and the U.S. will experience massive population growth. Some of those countries already face problems providing their people with sufficient food, energy and clean water.

“[USAID] sees the developing world as the future of the U.S. economy,” Dehgan said. “Many of these challenges aren’t just bad news. They’re challenges we can take on to develop our markets.”

To that end, Dehgan cited five trends that will help organizations tackle humanitarian challenges in the future:

  1. Democratization of Science
    It took researchers 13 years and 2.7 billion dollars to sequence a single human genome for the first time. Now a company can sequence 100 genomes a day for less than $100 each. Lower costs allow humanitarian groups to deploy innovative technologies (such as vaccines) on a large scale.
  2. Increase in Computing Power
    “The power of computing is increasing exponentially, while the cost is decreasing exponentially. This provides us with exceptional ability to use computer power to help understand and solve problems,” Dehgan said.
  3. Data, Data, Data
    “A kid in Africa has more power and knowledge in his hand with a smart phone than President Clinton had 15 years ago,” Dehgan said. Technologies such as remote sensing, crowd sourcing and bioinformatics will add new types of data to our pool of knowledge.
  4. Connectivity
    Cellphones act as gateways to human knowledge, providing people with access to information they didn’t have before.
  5. Decentralization of Manufacturing
    Certain 3D printers, for example, now have the ability to produce 70 percent of the parts needed for another 3D printer. Online course materials such as iTunesU and MIT OpenCourseWare help support individuals that are trying to solve their own problems.

Dehgan also says he hopes that a sort of “humanitarian X Prize” could identify solutions to our changing world by catalyzing new research.

In 1996, the X Prize Foundation announced a $10 million reward for the first group to launch a manned, reusable vehicle into space twice within two weeks. The foundation hoped to spur innovation that would make low-cost space flight possible, and they succeeded. The winning team claimed the prize in 2004, after investing $100 million in new technologies.

“With grants, you don’t know what you’re going to get,” Dehgan said. “If you have a prize, you only win the prize once you’ve actually solved the problem. And one of the great things about it is that you get more than one solution.”