Yvette Leal and Fernando Medina, both graduates of UTPA’s engineering program, designed a mesquite seed processor for a senior design project while they were students in the program. The device is designed to separate mesquite seeds from the hard outer hull, making the germination process much more efficient. The two and their faculty advisers, UTPA’s Dr. Robert Jones and Dr. Subhash Bose, donated the machine to Santa Ana in September to aid in habitat restoration efforts.
"We’re trying to restore native vegetation on about a thousand acres of refuge cropland every year," said Chris Best, a plant ecologist with the U.S. Fish and Wildlife Service working at Santa Ana. "We’re trying to restore the native type of forest and brushland and savannah that once occurred here.
"Of course, mesquite is one of the many species that occurred in this area. Sometimes ranchers don’t think too highly of mesquite, but it’s a fantastic species for wildlife. Deer, javelina — many different species feed on those mesquite beans," he said.
At the wildlife refuge, biologists currently grow the mesquite trees from seeds, then plant the seedlings. Planting seeds that will not germinate because of damage from insects or for other reasons means lost time.
"The fact that the seeds are in these little hulls and you can’t get them out means that we have no idea how high a quality they are. You can’t tell if they’ve been consumed by weevils or not, and it just makes it harder to work with. Being able to get the seed out of that little hull would just make our nursery operations a lot more efficient.
"The way we have to do it right now, we have to pregerminate the seeds to see which ones are going to come up, and then they’re transplanted into containers. That involves a certain amount of manual labor. It also means that every day — sometimes twice a day — you have to check to see which ones are germinating. If you wait one day too long, the roots get too long and they become very difficult to transplant.
"By having real high quality seed…we’re going to know that probably better than 95 percent of seeds are going to germinate," he said.
Leal and Medina, who were then seniors in mechanical engineering, designed and built the mesquite seed processor.
"We designed a machine to help separate the shell — the hull — from the seed itself to help them increase their germination rate," Leal said. "Right now they’re not having a very good germination rate, and what we tried to do is speed up that process so the seeds can start to grow."
Seeds within the hulls are placed into a hopper that feeds the seeds through a sand belt. When the seeds are put through the belt, the hulls are crushed off the seeds and the seeds and hulls come off the belt and drop into containers. Two passes through the machine, which cost only $470 in materials and $600 in labor to build, will remove the hulls from 90 percent of the seeds.
Leal, who is now a graduate student at UTPA, said the design project was an important learning experience.
"It wasn’t just all papers and calculations. We actually did it from the beginning, doing the design," she said. "It helps you, starting from scratch to actually design and build a machine and have an outcome that was actually going to help the (wildlife) refuge."
Jones, an assistant professor of engineering who served as one of the advisers to the students on the project, said that the idea for the project came out of a chance meeting with Best at the wildlife refuge. "He was telling us about how they’re restoring the lands that have been purchased for the South Texas Wildlife Refuge, and we started talking about some of the technical problems they deal with in sorting seeds and the poor yields they get," Jones said. "I said, ‘You know, that’s a good idea for a student senior design project at Pan Am. We’re looking for project ideas, and this would have a benefit for us as an educational opportunity and for the refuge.’"
A final requirement for all students graduating from UTPA’s engineering program is what is called a "capstone" engineering design project.
"The students take many of the things they’ve learned in their four or five years of study, and they have to put it together in an integrated engineering design problem," he said. "They design a product, build it, test it and verify that all the engineering of it was done correctly. The idea is that in the real world, that is what an engineer does."