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Design That Matters

Northwestern University

Olin College of Engineering

Innovate 3D

When most individuals think “future technology,” they probably imagine such things as personal helicopters, replicators, and even time-travel machines. But it can also be argued that there is a growing trend to bring technology back to earth, so to speak. Not everyone in the world has access to the tools needed to build hightech gizmos. So engineers and engineering schools are coming up with ways to help what is sometimes called “the other 90%” — that is, groups of people living in poverty, for instance, in the U. S., Asia, and Africa.

Cure for infants with jaundice
For example, a now-famous incubator for human infants was shown at a SolidWorks World event a few years ago. The device looked elegant and was easily made from cast-off car parts, which are handily had in most areas of the world. Better yet, the device cost a fraction of a conventional incubator. About two years ago, the same group, Design that Matters, Cambridge, Mass., began a project called Firefly, along with two partner organizations that have long-term experience serving communities in South East Asia, according to Director of Product Development Elizabeth Johansen.

“We are working with East Meets West Foundation and their local Vietnamese manufacturer, Medical Technology Transfer Services, to create all sorts of newborn-care devices,” says Johansen. “Our partners were looking for a device that would easily treat jaundice in rural hospitals. Jaundice affects 60% of all of newborns worldwide and can lead to permanent disabilities and severe brain damage, Johansen explains. If left untreated, as many as 10% of the infants that do have jaundice — or 6% worldwide — would end up permanently damaged. The most common treatment for infant jaundice is to shine blue-wavelength light on as much skin surface as possible. It penetrates into the blood and changes the bilirubin molecules (which cause the skin to look yellow) so they are cast out through the urine or stool.”

Newborn jaundice only happens during the first couple of weeks of life. “So once the baby is treated, it’s healthy for the rest of its life,” says Johansen.

Treatment devices don’t always reach rural hospitals because they are often made by local manufacturers and, thus, aren’t aesthetic enough to look professional. “The less training a doctor or nurse has, the less comfortable they feel using the devices,” says Johansen. “And some of the donated high-end devices look really good but often break quickly because they aren’t designed for use in the developing world.”

Project Firefly took a collaborative approach to the problem, marshalling hundreds of volunteers and contractors from academia and business to donate or charge very little for their expertise and resources. “Our approach leverages great technical expertise from the U. S., Europe, and parts of the Third World,” says Johansen.

The main challenges in designing the phototherapy device were designing something compatible with lowvolume manufacturing techniques or low-cost tooling so the Vietnamese group could take over the design, distribution, and servicing. “But the techniques still needed to give the device a high-quality, professional aesthetic,” says Johansen.

So, the bed the infant lies in is made from vacuum forming — a low-cost process, says Johansen. “The top light with the white housing is an aluminum extrusion. The extrusion tool is low cost. The two end caps are injection molded from plastic. A stainless-steel tube holds up the light. We were able to outfit the Vietnamese manufacturing company with its own tube-bending capabilities at a low cost,” she says.

The plastic base is made from reaction injection molding, where a high-tonnage press is not necessary. The injected plastic creates its own pressure through chemical reaction.

Other innovations for the device concerned the optics and thermal issues. “The problem was trying to find a setup that used high-power LEDs in the top lights in an aluminum extrusion and still have the light be even,” says Johansen. The solution was two strips of five LEDs that mount at an angle inside the light.

“The cost to manufacture the device is a fraction of the cost of the most-common overhead phototherapy devices in the U. S.,” she says. “Plus, almost no other device on the market produces both top and bottom lighting to reach more of the infant’s skin. So another challenge involved cooling. Most U. S. hospitals are air conditioned, but in this environment, the hospitals can be around 95°F. Therefore, managing heat in the LEDs in the base was a big deal. Thus, the base is completely sealed for thermal management, which also stops insects from crawling into the lamp. A metal heat sink in the bottom carries the heat away. The device has no fan either. A lot of donated equipment has fans and they are often one of the first things to break,” she says.

The group just completed the clinical trial in 2011 and has cured many newborns of jaundice so far, says Johansen. “We are getting the final vendors in place to ramp up production in 2012. The project has expanded into India, the Philippines, and Cambodia,” she says.

An inexpensive but elegant prosthetic foot
In the early 1990s, Dudley Childress, a professor at Northwestern University, and one of his graduate students, Erick Knox, were trying to understand the important features of prosthetic feet and how that relates to people walking. They found that the effective rocker shape — later called the rollover shape — that the ankle-foot combination makes during walking is a very important attribute for feet and determines whether the person perceives a smooth rollover.

Around the same time, Andrew Hansen, now a researcher at the Minneapolis VA Health Care System and an adjunct associate professor in physical medicine and rehabilitation at Northwestern University, started to research the rollover shape and understand how it changes for able-bodied people when they walk fast or slow, carry different amounts of weight, wear different shoes — all things that amputees would like to do. “The idea was that if we knew that information we could try to design prosthetic feet to mimic those changes. We found that the rollover shape is very consistent for different speeds and weights. So if you pick up a backpack and walk, the rollover shape stays the same. Even when wearing different shoes, people adapt their ankle movements to keep the rollover shape the same. This was an exciting thing to learn. About the same time, Childress was collaborating with an agency called the Center for International Rehabilitation (CIR), which funded us to apply some of this science toward the development of an inexpensive but biomimetic prosthetic foot that mimicked what able-bodied persons were doing with their ankle-foot system during walking,” he says.

Knox had similar ideas and developed what he called the Shape Foot.

“The Shape Foot was made from a 2 × 4 and cut to a rocker shape, then connected to the prosthesis,” says Hansen. “Sounds hard to believe but people could actually walk quite well with it. The Shape Foot doesn’t have all the important features of a foot, of course, but people could get pretty good walking function. The problem was the Shape Foot really wouldn’t fit into a shoe — and if it did, it would curl up the shoe and look funny.”

Childress then worked with his team to convert that prosthetic foot into something that could be made easily and in resource-limited areas. “I was a grad student at the time helping other people on the design of the foot. We were trying to come up with a foot that would conform to a rocker shape and then stop. Childress pulled a comb out of his pocket and bent the tines of the comb together saying what if we did something like this. That is the basic idea that led to the final design.”

The design is now a plastic foot with a series of saw cuts in the forefoot, which are placed in such a way that the cuts close in succession and create a biomimetic rollover shape for walking. “We put a lot of effort into the design and verifying that we were getting the right rocker shape,” says Hansen. “We did fatigue testing of the foot and also had some studies of the foot in Chicago as well as El Salvador. Since that time CIR has done more extensive testing and dissemination of the foot in other areas of the world.”

The project is open source with downloadable instructional manuals (http://www.nupoc.northwestern.edu/research/lowerlimb/sr_footkit.html) on how to make the feet and the compression molding devices for the feet. “In the end, we used a lever-compression mold, which we liked because it uses gravity to get the compressive forces,” says Hansen. “It’s kind of like a large nutcracker that squeezes plastic into a shape instead of cracking nuts.”

In more detail, the way to make the feet is to first put two layers of plastic in an oven. Next, put the floor of the mold in the lever, then some plastic, then a mandrel, then more plastic. Then close the lever. “We let everything cool on the mandrel and then pull it out of the plastic piece,” says Hansen. The resulting blank can be used to create one of eight different feet — four different sizes, right or left. We tried to keep the number of molds low and make the feet different by how they are cut out in second operations.”

The group also considered what kind of plastics would be available in the target areas. “Many emerging areas are already doing prosthetics and orthotics types of fabrication and they would have plastics like polypropylene and polypropylene-polyethylene copolymers. “In testing, polypropylene had a brittle failure mode, so we use copolymer plastics,” says Hansen. “We could use thinner layers of plastic — the same plastics used in making prosthetics sockets for the residual limb. Better yet, we can use scraps that were too small to make prosthetic sockets or orthoses. The materials to make the foot are around $10 to $20. The thought was to try to use as much material as possible, which would otherwise be wasted. The copolymer plastics don’t have the brittle failure, more of a ductile failure; and the feet passed the test modeled after the ISO testing for prosthetic feet.”

Engineering for the other 90%
Professor Benjamin Linder of Olin College of Engineering in Needham, Mass., believes there is a trend in engineering schools towards meeting the needs of people living in poverty. “Our joint program with Babson College, Babson Park, Mass., is called Affordable Design and Entrepreneurship. The aim is to provide students with the education to design for and with the other 90%. The idea popularized by Paul Polak is that design should not just be aimed at the world’s better-off 10%. That is, we need to also design for the base of the pyramid and emerging markets, where many people live on the equivalent of $1 or $2 a day or less.” Paul Polak is the founder of International Development Enterprises and cofounder of Windhorse International, both located in Denver.

What is needed are strategies that are sustainable and scalable, says Linder. “We go after all of the innovation options available — whether it’s technology or business innovation, or both,” he says. “In some cases it might be a new technology, in some cases the needed technology exists but it can’t be delivered without a business innovation.”

The program runs every semester as a “firm within a course” in which students work to deploy products and social ventures around the world. “We are now working in communities with partners in the U. S. (Alabama), Ghana, India, and Morocco,” says Linder.

One student team is working with Rickshaw Bank, a rickshaw manufacturer in India. “They provide microfinancing so that rickshaw pullers can own their rickshaws and increase their incomes,” says Linder. “Students designed a retrofit kit that gives pullers two speeds, which they did in collaboration with Gwyn Jones and his Cycle Ventures course at the Massachusetts Institute of Technology. Their design really reduces the burden on pullers that is so high when it is loaded with passengers and stuff, which is to say most of the time. The team went back and forth between the U. S. and India to prototype and test the kit. The mechanism is being made in India locally.”

The design was a significant mechanical challenge, says Linder. “Rickshaw pullers are opposed to cables, road conditions are punishing, and chain hopping is common. Plus, the design had to be low cost.”

In another project, a team is exploring a mobile phone app that lets riders call a rickshaw for pickup. “Many rickshaw pullers have mobile phones,” says Linder. “So this approach can provide a better service for riders and more income for rickshaw owners without much added cost.”

© 2012 Penton Media, Inc.