Conference Paper Submission System, ASEE North Central Section Conference April 3-4, 2009 (S)

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Designing Tools for Harvesting Amaranth in Developing Countries

Aubrey Sykes

Last modified: 2009-03-23


Amaranth is one of the most promising solutions for providing protein and beneficial byproducts to developing countries. As a high-protein grain that grows under less than desirable conditions, its current obstacle to widespread use is the lack of simple-to-use farm implements.
The engineering students at Calvin College in Grand Rapids, Michigan, took on the challenge of developing appropriate tools to recover a clean product. Three separate projects focused on each of three processing steps: (1) thrashing to separate some 6000 seeds from a dense head, (2) winnowing to clean the seed of its hull and chaff at a high recovery rate, and (3) efficiently popping the seed to produce the major component of a super-nutritious, delicious bar. For each of these, the ultimate goal was a seed that could be eaten in some form.
Students began each project by analyzing the current practices of farmers in developing countries; each practice was evaluated for appropriate mechanization. An undergraduate in a summer research project undertook a preliminary study of thrashing. Seniors, in teams of three to five students, also designed and built prototype machines to winnow and pop amaranth. These machines were built to standards of minimal complexity, easy maintainability, pictographic operation and maintenance manuals, transparency and safety.
Most engineering education focuses heavily on the deployment of state-of-the-art technology; high effectiveness and efficiency with minimal capital and energy expense are held up as high standards. However, deploying technology into developing countries in an appropriate way requires engineering students to rethink many of their fundamental assumptions. For example, the thrashing and winnowing machines both have specifications that the machines must be easily moved from field to field or village to village by two women on “roads” that are often heavily rutted paths cleared through trees and brush. Both of these machines need to be people powered, typically by young boys or women, so great forces are not possible. Frequently, the power mechanism is bicycle pedal power, and the mechanisms must be guarded so that women in long, flowing dresses can deliver the power. The transparency of the operation must be impeccable, since many different users with no operational training will likely use it.
The prototype machines for winnowing and popping have been copied and are now being deployed into developing countries. The winnowing machine has over 90% recovery of the amaranth seed and produces a clean product that is ready for grinding into flour--for meal or mush--or for popping. The winnowing machine was equipped with a “mini-thrasher” to remove seeds from tiny branches and twigs that came from the thrashing. When 12 of these machines were deployed across the globe over a short period, some of the early adopters took this thrasher as intended for the entire amaranth head! This thrasher was not designed for the full head; addressing this misunderstanding has been a challenge, requiring case-by-case discussion.
When the popping machine was first analyzed for feasibility, the Senior Design Student Team strongly recommended that the heat source be a hydrocarbon fuel; however, the client maintained his specification for a 220-v electricity-based design. The students designed, built and operated a prototype as specified, but also did a preliminary design for a natural gas or propane fired popping machine. Upon delivery of the prototype, along with its design and testing results, the Senior Design Team again strongly recommended that the prototype be converted to a hydrocarbon fuel. Upon taking the prototype, the client then worked with a graduate student engineer from a university near to his operation base to convert the prototype to propane. After operational testing, copies of this modified prototype are now being deployed into Africa.
In the early studies of the thrashing machine challenge, information came forth that there were two different varieties of amaranth being introduced in developing countries. Agronomists are not yet able to give guidance on the preferred variety. However, field data has indicated that the maturation process for these two varieties is different—affecting the type of processing within the thrasher and the yield from each amaranth plant head. Furthermore, local weather and climate seem to affect the condition of the seed head at the time of its thrashing. A multi-page specification sheet has been distributed to representative field sites to collect the information required to delineate an effective design. Work is underway to collect this information with potential users of the thrasher in various regions of the globe. More development and design studies are needed for the thrashing machine before production is begun.
These projects have provided students a great opportunity to reframe their engineering education—leading to a deeper understanding and improved application, to rethink their career options, and to provide a valuable service to people in developing countries.

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