Michael Sama,John Evans 2016-08-24 04:06:05
Biosystems Engineering Design I and II, commonly referred to as Senior Design, is a two-semester Capstone series that provides real-world experience with discipline-specific design projects for seniors in biosystems engineering. In recent years, 10 to 30 students have been enrolled in Senior Design. The students are assigned to teams of three or four based on their area of interest. Teams are assigned a faculty mentor and, in many cases, a client who has requested engineering support to solve a real-world problem. The projects typically fall into one of four disciplines within BAE: bioenvironmental, food and bioprocessing, machine systems, and pre-biomedical. The teams are required to formulate a problem statement, determine the motivating economics, produce a preliminary design, report on their design, consult with advisors and the client, produce a final design, and then fabricate and test the end product. Throughout the year, the teams are also given formal lectures on ethics, economics, statistics, drafting, and written and oral communication to make sure they have all of the tools needed to successfully complete their project and effectively present the results. A notable project during the 2012-2013 academic year was proposed by Robert Klingenfus, owner and operator of Harvest Home Dairy in Oldham County, Kentucky. Mr. Klingenfus had recently converted his 110-cow freestall barn to a compost bedded pack (CBP) barn. CBP barns replace the individual stalls found in freestall barns with a large open bedding area, where manure is composted in place rather than being removed daily. Controlling moisture is crucial for proper operation. Excessively high moisture impedes aerobic decomposition, which causes CBP barns to fill up faster and produce greenhouse gases (e.g., NH3 and CH4) at a higher rate. Regular aeration and incorporation of a carbon source (typically wood shavings) are key management practices to ensure thorough composting and a dry bedding environment for the cows. Mr. Klingenfus was particularly concerned about the need to aerate the CBP. Unlike windrow composting, the CBP must be mixed in situ, which limits the types of tractors and implements that can be used inside the facility. In Kentucky, many producers use older model tractors of 44 to 60 kW with rototillers or cultivators to aerate CPBs. Rototillers, while providing an excellent surface finish, do not aerate and mix the material below 20 cm. Cultivators tend to leave large clumps of material on the surface, which limits the drying rate. Both tools result in a partially composted system in which only a portion of the CBP is actually aerobically decomposing. Other available tools, such as rotary spaders, require more power than is typically available. This concern led Mr. Klingenfus to inquire about developing a custom tillage tool that would provide a good surface finish while digging deeper, to increase the depth at which aerobic decomposition could occur. It was a great opportunity for undergraduate students in need of their first comprehensive design project. John Evans, Jeff Clark, and Stephanie Hunt were given the task. The team ultimately settled on a hybrid tillage system that included a traditional rototiller coupled with an adjustable-depth deep-shank tillage tool. Designing the custom tillage tool required applying the engineering principles they had learned in tillage, traction, mechanics, and hydraulics to a real-world problem for which many of the parameters and constraints were unknown or difficult to predict. The team worked alongside staff engineers and machinists at the Agricultural Machinery Research Laboratory (aka “The Shop”) to fabricate the system, and they ultimately tested it at Mr. Klingenfus’ farm. The results were greater than anyone expected. Not only did the custom tillage tool function, it worked so well that we had to pry it away from Mr. Klingenfus just to make modifications the following year! The same tool has been in use at the farm for over three years now. Mr. Klingenfus reports that the tool has improved herd health and reduced the amount of bedding material needed to operate, providing an annual cost savings of $10,000 to $35,000. Editor’s note: John Evans went on to complete an MS under Dr. Michael Sama, where he continued to develop the system by adding forced aeration and a novel data acquisition system for wireless monitoring of the spatial distribution of oxygen within the CBP to measure the system’s effectiveness. Evans is currently pursuing a PhD in biological engineering at the University of Nebraska-Lincoln. He credits his experience with Senior Design for giving him the inspiration to pursue his graduate degrees, with the goal of providing engineered solutions for the problems that producers face.
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