Engineering Solutions the Hands-On Way

November 14, 2008

This fall, students in Laurens Howle’s ME141L course were given a challenge and their mission was to conceive of a solution, design it, and finally build it. The challenges for this course may change semester to semester, but the goal is the same: giving students the experience of developing something from beginning to end.

ME141L student teamThe current class has been charged with designing and building the next generation of flippers for SCUBA divers based on the same principles that guide the propulsion of fish or aquatic birds. The project is a part of Howle’s work with the Defense Advanced Research Projects Agency (DARPA) to improve the swimming capabilities of combat or reconnaissance swimmers.

Coming up with solutions for real-life challenges is one of the hallmarks of the course. Students are divided into small groups and presented with a real problem from a real client who could use the solution in the real world. In short, they are asked in the span of one semester to analyze a problem, design a solution, fabricate the device and demonstrate its functionality.

“Experiences like this harken back to ‘70s when engineering education was more a combination of the theoretical and the practical,” Howle said. “After that the pendulum swung to the theoretical side of things, but we are now seeing a resurgence in hands-on courses in engineering.”

Howle’s previous ME141L course is a telling example of this soup-to-nuts approach.

Dr. Rendon Nelson, a radiologist at Duke Hospital, brought a clinical problem to the class to solve. He had worked with Howle before on other projects and thought the class could help him solve a challenge he faced in the hospital.

In order to interpret an image and diagnose a patient, Nelson must obtain clear pictures of such soft tissues as the liver, spleen or pancreas. He often uses computed tomography (CT) technology to take these pictures. To get the clearest image possible, Nelson must give the patient an intravenous injection of a contrast agent. The agent needs to be given in one steady and continuous dose, and many patients need doses as large as 150 milliliters.

“Most nurses are not strong enough to push the plunger in a syringe that large,” Nelson explained. “To compensate, the agent is often administered from a series of smaller syringes. While that makes it easier for the nurses, it can lead to less-than-optimal images because the doses rise and fall as each syringe is used. We needed a device that nurses could use to deliver a steady dose of the agent.”

At the beginning of the semester, Nelson came to the class and explained the problem and provided the technical specifications of what was needed. Within a month, each group presented a PowerPoint presentation of their ideas, and not long after that they had fashioned prototypes for Nelson to evaluate.

“Even though each team came up with a different approach to the same problem, I could tell they were all really engaged and had put a lot of thought into it,” Nelson said.

The course not only gave students firsthand experience in developing an idea from beginning to end, but also exposed them to other important aspects of product development, such as working with a client and incorporating their input, dealing with costs and ordering issues, and overcoming unforeseen roadblocks.

“We were under a tight deadline, so we had to delegate all the different aspects of the project,” said Scott Steinberg, a senior biomedical engineering major. His team’s prototype was selected as the class’s best. Other students in the team were Ryan Ptera, Mark Riherd, Alexander Robinson, Todd Stamp, Scott Steinberg, Bryan Stem, Maryanne Uselton, Anne Vanderschueren, Andrew Ward and Miles Whitten.

“Each person had a specific responsibility, ranging from ordering parts to constructing the device to finite element analysis,” Steinberg said. “We also got the opportunity to use tools like the jigsaw, lathe and milling machine. That was the first hands-on experience I had since high school.”

The final product made use of gears turned by a large “steering” wheel. As the wheel is turned, the device easily pushed the plunger into the syringe, dispensing the contrast agent.

While the appearance of the prototype will likely change, the students are planning to patent the device in hopes that a medical instrument company will become interested in developing it into a product.

“All the teams did a great job,” Howle said. “What I especially liked about it is that they used what they learned during the class to guide the development of the device they ended up building. I was also impressed how they were able to overcome the obstacles and setbacks that they all encountered.”