Integrating perennial groundcovers (PGC) — sometimes referred to as living mulches or perennial cover crops — into annual cash-crop systems could address root causes of bare-soil practices that lead to negative impacts on soil and water quality. Perennial groundcovers bring otherwise absent functional traits — namely perenniality — into cash-crop systems to preserve soil and regenerate water, carbon, and nutrient cycles. However, if not optimized, they can also cause competitive interactions and yield loss. When designing PGC systems, the goal is to maximize complementarity — spatial and temporal separation of growth and resource acquisition — between PGC and cash crops through both breeding and management. Traits of interest include complementary root and shoot systems, reduced shade avoidance response in the cash-crop, and PGC summer dormancy. Successful deployment of PGC systems could increase both productivity and profitability by improving water- and nutrient-use-efficiency, improving weed and pest control, and creating additional value-added opportunities like stover harvest. Many scientific questions about the inherent interactions at the cell, plant, and ecosystem levels in PGC systems are waiting to be explored. Their answers could enable innovation and refinement of PGC system design for multiple geographies, crops, and food systems, creating a practical and scalable pathway towards resiliency, crop diversification, and sustainable intensification in agriculture.

Technoeconomic analyses using established tools such as SuperPro Designer^® require a level of detail that is typically unavailable at the early stage of process evaluation. To facilitate this, members of our group previously created a spreadsheet-based process modeling and technoeconomic platform explicitly aimed at joint fermentative‒catalytic biorefinery processes. In this work, we detail the reorganization and expansion of this model—ESTEA2 (Early State Technoeconomic Analysis, version 2), including detailed design and cost calculations for new unit operations. Furthermore, we describe ESTEA2 validation using ethanol and sorbic acid process. The results were compared with estimates from the literature, SuperPro Designer^® (Version 8.5, Intelligen Inc., Scotch Plains, NJ, 2013), and other third-party process models. ESTEA2 can perform a technoeconomic analysis for a joint fermentative‒catalytic process with just 12 user-supplied inputs, which, when modeled in SuperPro Designer^®, required approximately eight additional inputs such as equipment design configurations. With a reduced amount of user information, ESTEA2 provides results similar to those in the literature, and more sophisticated models (ca. 7%–11% different).

Many experiences in engineering education boast positive gains to students’ learning and achievement. However, current literature is less clear on the economic costs associated with these efforts, or methods for performing said analyses. To address this gap, we proposed a structured approach to analyzing the incremental costs associated with an experience in engineering education. This method was modeled after those found in medicine and early childhood education. We illustrated our methodology using marginal (above baseline) time and cost ingredients that were collected during the development, pilot, and steady-state phases of a mechatronic experience in a first-year undergraduate engineering technology course. Specifically, our method included descriptive analysis, Pareto analysis, and cost per capacity estimate analysis, the latter of which has received limited discussion in current cost analysis literature. The purpose of our illustrated explanation was to provide a clear method for incremental cost analyses of experiences in engineering education.We found that the development, pilot, and steady-state phases cost just over $17.1k (approximately $12.4k for personnel and approximately $4.7k for equipment), based on 2015 US$ and an enrollment capacity of 121 students. Cost vs. capacity scaled at a factor of – 0.64 (y = 3,121x–0.64, R2 = 0.99), which was within the 95% interval for personnel and capital commonly observed in the chemical processing industry. Based on a four-year operational life and a range of 20–400 students per year, we estimated per seat total costs to range from roughly $70–$470, with our mechatronic experience averaging just under $150 per seat. Notably, the development phase cost, as well as the robot chassis and microcontroller capital cost were the primary cost terms of this intervention.

Iowa's livestock produces over 50 million tons of wet-basis manure each year. Biogas production from the manure can provide additional income to farmers, reduce greenhouse gas emissions, control odors, and provide a renewable energy source. Despite these benefits, biogas production is rarely deployed at swine farms. In this work, we explore the system economics to understand better the reasons for low deployment, as well as the benefits that might be realized via several additional steps, including: (1) cleaning and injection into the natural gas grid, (2) amending manure with biomass, and (3) digester centralization. Specifically, we present a static, spreadsheet-based techno-economic model that allows examining these scenarios and combinations thereof. We also present our results and the uncertainties therein. This work shows that under the model assumptions, distributed, farm-scale digesters are not competitive with natural gas prices in Iowa, while some centralized production scenarios can be competitive, providing that fertilizer value and RIN credits are sufficiently high.

Amaranth (Amaranthus spp.) is used as a vegetable, food, forage, and sometimes an ornamental. Amaranth grain has higher protein content than other cereals, making it a good choice for human consumption. Maize is among the three most widely grown grains in the world, but it can experience large postharvest losses during storage due to infestation by the maize weevil (Sitophilus zeamais). Due to the small size of amaranth seeds, this study postulated that amaranth grain can be blended with maize during storage to fill the intergranular spaces between maize kernels, reducing the overall void volume to minimize maize weevil movements to access the kernels, and thereby controlling the maize weevil population. The objective of this study was to investigate the effects on maize weevil control of blending maize with amaranth grain during storage versus storing maize alone. Three 208 L (55 gal) steel barrels were loaded with 160 kg (353 lb) of maize, and three were loaded with a maize-amaranth mixture (1:1 by volume), all with initial weevil populations of 25 live weevils per kg of maize. Blending maize with amaranth for storage reduced the number of live weevils after 160 days by 66% compared to storing maize alone. Additional reduction of live weevils could be accomplished if the maize were completely covered by amaranth grain, further restricting maize weevil access to the maize kernels.

Bioenergy cropping systems afford the prospect to provide a more socially and ecologically sustainable bioeconomy. By creating opportunities to diversify agroecosystems, bioenergy crops can be used to fulfill multiple functions in addition to providing more environmentally benign fuels. Bioenergy crops can be assembled into cropping systems that provide both food and energy and which also provide cleaner water, improved soil quality, increased carbon sequestration, and increased biological diversity. In so doing, they improve the resilience of agroecosystems and reduce risks associated with climate change. Beyond the farmgate, bioenergy crops can improve the economic prospects of rural communities by creating new jobs and providing opportunities for local investment.

Educational literature has long supported strong correlations between student motivation and academic success. STEM literature has more recently shown mechatronic experiences to have positive impacts on these constructs, albeit limited empirical grounding. Therefore, the purpose of this study was to conduct a pilot experiment to empirically quantify differences in undergraduate student motivation and academic success in a mechatronic vs. a non-mechatronic experience, as well as examine the correlation between student motivation and academic success in both groups. We used a quasiexperimental, non-equivalent control vs. treatment design to collect n = 84 responses from multiple sections of a single undergraduate course. The multivariate dependent variable of student motivation was measured using the Motivated Strategies for Learning Questionnaire’s motivational orientation items. Our multivariate dependent variable of academic success was based on final course grades, final project scores, and quiz scores. Using ANCOVA and differences of proportions, we found no statistical difference in motivational orientation—specifically value choices and expectancy beliefs—in the mechatronic vs. non-mechatronic experience. In contrast, statistically significant differences in project scores and final course grades were observed in the mechatronic experience group. Additionally, we found no significant correlation between student motivation and academic success. These results indicated that students in the mechatronic experience, while earning significantly higher grades, did not exhibit different levels of motivation, leading to no association between student motivation and academic success. Even so, future research is needed to further understand the nuanced dynamics of motivational orientation within a mechatronic experience.