Engineering Commons^™

Representativeness Evaluation Of Delta-Flux Eddy Covariance Towers For Assessing Greenhouse Gas Emissions From Rice Fields In The Mid-South Region, Katherine Skiles

Biological and Agricultural Engineering Undergraduate Honors Theses

Rice grown in 5 states across the Mid-South (AR, LA, MS, TX, and MO) account for nearly 80% of all domestic U.S. rice production. Methane emissions produced during rice farming and the large seasonal water demand to maintain flooded fields have created a need for alternative irrigation research that can reduce methane emissions and conserve water. Structures called eddy covariance towers (ECTs) can observe methane and other flux responses to changing irrigation styles, and their data is shared across flux tower networks such as Delta-Flux in the Mid-South. The Delta-Flux network is relatively new, and its data-sharing capacity is not …

Non-Energy Circular Economy Potential Of Rice Husks: A Techno-Eco-Environmental Assessment, Winfred Oppong Yeboah

Graduate Theses and Dissertations

The non-energy circular bioeconomy potential of rice husks was examined via sustainability assessments, namely life cycle assessment (LCA), life cycle impact cost assessment (LCICA), and techno-economic assessment (TEA). The study was conducted with three objectives. The first objective was to review previous studies on the non-energy utilization potential of rice husks by the method of meta-analysis. This review followed a systematic approach where research papers were collected following a defined set of criteria. The study revealed 16 key utilization pathways, all of which showed promising results. However, a comprehensive sustainability assessment was lacking in all of the pathways. The second …

The Influence Of Pesticides On Us Corn Production Environmental Impact: A Comparative Life Cycle Assessment Of Dominant Production Practices, Kyle Marinoni Lawrence

Graduate Theses and Dissertations

In recent years there has been increasing interest in reducing agricultural environmental footprints in the United States, particularly for commodity crops like corn grain. Pest management is one aspect of agricultural production that is often identified as having potential for improvement with regard to environmental impact, but there is not a robust body of literature to identify the wide-scale influence of pesticides on yield and environmental impact. In this study, we hypothesized that the use of different classifications of pesticides has a significant impact on the overall environmental impact. To test this, agricultural models were created to represent the dominant …

Analyzing Energy Use From Arkansas Public School Buildings, Oscar Morton

Biological and Agricultural Engineering Undergraduate Honors Theses

Energy is a key global resource in society and greenhouse gas (GHG) emissions related to the consumption of energy have detrimental effects on the planet. With energy consumption increasing, exponential population growth, and diminishing natural resources necessary for energy production, the relevance of energy efficiency is dramatically increasing. In this project, I analyzed energy usage data from a set of public school buildings from one school district in northwest Arkansas from 2018, before targeted energy efficiency practices were implemented, through 2022 to see if energy usage changed over this short period. The objectives of analyzing energy data were to determine …

Sustainability And Health Impacts Of Pulse Crops In The United States Using Life Cycle Assessment, Prathamesh A. Bandekar

Graduate Theses and Dissertations

Environmental sustainability and human health impact of pulses produced and consumed in the United States was assessed using life cycle assessment (LCA). The study included three objectives 1) to estimate environmental impact of current production and consumption practices in the United States using attributional LCA; 2) to estimate environmental and human health impact of iso-caloric diets containing varying amounts of pulses using Hybrid-LCA and Combined Nutritional and Environmental-LCA (CONE-LCA); and 3) to estimate environmental impact of increased demand for pulses using consequential LCA. Scope of the study varied for each objective with system boundary encompassing cradle-to-grave activities for objective 1 …

Precision Weed Management Based On Uas Image Streams, Machine Learning, And Pwm Sprayers, Jason Allen Davis

Graduate Theses and Dissertations

Weed populations in agricultural production fields are often scattered and unevenly distributed; however, herbicides are broadcast across fields evenly. Although effective, in the case of post-emergent herbicides, exceedingly more pesticides are used than necessary. A novel weed detection and control workflow was evaluated targeting Palmer amaranth in soybean (Glycine max) fields. High spatial resolution (0.4 cm) unmanned aircraft system (UAS) image streams were collected, annotated, and used to train 16 object detection convolutional neural networks (CNNs; RetinaNet, Faster R-CNN, Single Shot Detector, and YOLO v3) each trained on imagery with 0.4, 0.6, 0.8, and 1.2 cm spatial resolutions. Models were …

The Effect Of Water Management And Ratoon Rice Cropping On Methane Emissions And Harvest Yield In Arkansas, Marguerita Leavitt

Graduate Theses and Dissertations

Sustainable intensification of rice farming is crucial to meeting human food needs while reducing environmental impacts. Rice produces 8% of all anthropogenic CH4, which is a potent greenhouse gas. CH4 emissions can potentially be reduced by cultivation practices that minimize the number of days the fields are saturated, such as dry-seeding instead of water-seeding and irrigation using the alternate wetting and drying (AWD) technique instead of delayed, continuous flooding (DF). Ratoon cropping, wherein a second crop of rice is grown from the harvested stubble of the first crop, can be used to produce additional yield with minimal labor, but may …

Cyanobacterial And Microcystin Response To Nutrient Additions At Lake Fayetteville Throughout The 2021 Growing Season, Lillie Haddock

Graduate Theses and Dissertations

Harmful Algal Blooms (HABs) are becoming a global concern due to their increasing distribution, frequency, intensity, and the occurrence of toxins. While it is known that eutrophication influences algal blooms, there is less known about what triggers these HABs to produce toxins, especially microcystin. In this study, we conducted 21 community bioassays at Lake Fayetteville, a hypereutrophic reservoir in Fayetteville, Arkansas, from April-November 2021 to examine how the addition of phosphorous and nitrogen influence cyanobacteria concentrations, microcystin concentrations, and microcystin toxin production. These experiments included a control, nitrogen (1.0 mg/L as KNO3), low phosphorus (0.025 mg/L as K2HPO4), high phosphorus …

The Environmental And Nutritional Dilemma Of Beef Production And Consumption, Hannah A. Swilling, Stefano De Rosmini, Brooke Lovan

Chemical Engineering Undergraduate Honors Theses

Based on previous studies, it has been stated that beef production and consumption in the United States is detrimental to the environment. However, in depth studies analyzing the change of beef production and consumption, the environmental impacts, the external costs, the lifestyle implications as well as the nutritional, the social and the cultural aspects of beef have not been conducted. The goal of this study is to analyze the multiple aspects of the dilemma over beef production and consumption. This was done through an analysis of beef production and consumption data over the past 60 years to determine how it …

Modeling Leaf Area Index And Canopy Height Using Growing Degree Days, Ellie J. Kuhn

Biological and Agricultural Engineering Undergraduate Honors Theses

As the global population increases and food security is recognized as a critical issue, crop growth prediction models help ensure the sustainability of reliable food sources. Using a prediction model based on temperature and simple, measurable field parameters, e.g., Leaf Area Index (LAI) or Canopy Height (H_can), may allow farmers and others to intervene mid-season with fertilizer, irrigation, or other inputs to obtain a better harvest.

This study aims to create a general model that could predict LAI and H_can values for numerous rice varieties using Growing Degree Days (GDD) as the time scale. The models use …

Potato Processing In The Home: Sustainability And Nutritional Impacts, Aubin Payne

Biological and Agricultural Engineering Undergraduate Honors Theses

Potatoes are the world's fourth most consumed crop. Their versatility and long shelf-life make them a staple food for millions of people worldwide. Still, the increasing consumption of highly processed potato products in developed countries has damaged the public's appreciation of potatoes as a valuable source of essential nutrients. Additionally, as public awareness of environmental sustainability increases, the average consumer is more likely to value processing methods that mitigate environmental damage.

Researchers simulated several home storage and processing conditions to find out how nutrition and environmental impact are affected by the home processing timeline. Then, a nutrient analysis, life cycle …

Sensory Comparison Of Beer Carbonated Using Forced Carbonation And The Carbo Rock-It, Michala Smith

Biological and Agricultural Engineering Undergraduate Honors Theses

Craft brewing is a growing market which represents over 12% of beer produced in the United States. Dr. G Scott Osborn, PE invented the Carbo Rock-It™ to improve the carbonation process for craft breweries. The invention allows for shorter carbonation time and uses less CO₂, saving companies money and time. Because of the lack of gas losses through bubbling, Osborn theorized that the Carbo Rock-It could also prevent the “stripping of the nose” that can occur in traditional forced carbonation. Existing research supports the mechanism, as beer flavor and aroma volatiles have been detected during the release of …

Climate Change Impacts And Engineering Solutions, Dawson Oakley

Biological and Agricultural Engineering Undergraduate Honors Theses

With climate change entering the forefront of global issues, the need for sustainable practices that can provide for human welfare, social and economic development, and health has become more urgent than ever. Despite the recent increase in climate change impacts around the world, many people are still unaware of the severity of the situation. Changing public perception of these issues is the first step in enacting change and increasing accessibility to this information plays an important role.

Much of the information people consume today comes in the form of video, and it can be an effective tool to change knowledge …

Exploring The Effects Of Varied Land Use On Elemental Concentrations Within Streams, Logan Jennings

Biological and Agricultural Engineering Undergraduate Honors Theses

It is well documented that human activity influences the chemistry of surrounding waters. As such, it is possible that there is a link between land use within a watershed and the chemical composition of the stream. The objectives of this study are to determine if varied land use does affect the concentrations of macronutrients and trace elements present in the streams of Northwest Arkansas, and if so, to determine what extent urban and agricultural development are responsible for these changes. Water samples were collected across 19 streams in the Northwest Arkansas region between January and March of 2022. Water samples …

An Engineering And Economic Analysis Of The Implementation Of The Carbo Rock-It, Lydia Huck

Graduate Theses and Dissertations

The patented Carbo Rock-It system was developed to carbonate beverages for the craft brewing industry with the goal of reducing time, cost, and environmental impacts of the carbonation process. This research field tests, models, analyzes and optimizes the engineering and economic performance of a commercial-scale Carbo Rock-It placed in production at an operating brewery (Core Brewing and Distilling Co., Springdale, AR). Field tests indicated that the Carbo Rock-It was able to successfully carbonate twelve 120 BBL batches of Scarlet Letter Seltzer to 3.0 vol/vol while meeting all beverage quality and safety requirements. The Carbo Rock-It was able to reduce carbonation …

Optimization Of Nitrogen Removal Rate In One-Stage Reactor Through Partial Nitrification Anammox Process During Direct Treatment Of Poultry Litter Wastewater, Yiting Xiao

Graduate Theses and Dissertations

Anammox is an increasingly common process used for the treatment of reject water and even mainstream wastewater due to its low oxygen demand. However, anammox is not commonly utilized in the direct treatment of poultry litter because of the high organic content, which would inhibit the anammox process. Thus, this project is aimed at optimizing the nitrogen removal rate through partial nitrification anammox process (PN/A) to treat synthetic poultry litter wastewater. Nitrogen removal efficiencies will therefore be improved through optimizing the combination of three operating parameters including hydraulic retention time (HRT), dissolved oxygen (DO) concentration, and carbon to nitrogen (C/N) …

Evapotranspiration In Mid-South Rice Production, Colby Wade Reavis

Graduate Theses and Dissertations

Rice provides much needed sustenance to a large portion of the global population, particularly in the developing world. With stress placed on food production systems under the reality of climate change and an increasing global population, rice production systems require solutions to a number of issues, including a limited water supply. As producers explore new strategies for conserving local water resources to continue to maintain yields, new irrigation strategies and technologies are being developed and validated for use at commercial production scales. Alternate wetting and drying (AWD) is an irrigation practice that provides water savings through the capture of rainfall …

Identification Of Phosphorous Loading Point Source Facilities To 303(D) Listed Nutrient Impaired Waters Through Watershed Delineation Using Arcgis For Life Cycle Assessment Applications, John Zimmerman

Chemical Engineering Undergraduate Honors Theses

The work done for this project is part of a larger “life cycle assessment (LCA) of novel electrochemical phosphorus recovery technology at the wastewater treatment plant and U.S. watershed scales” (Morrissey 2019). The goal of that LCA is to determine “environmental impacts of implementing electrochemical struvite recovery at the wastewater treatment plant, U.S watershed, and global scales” (Morrissey 2019). This project’s goal is to identify locations deemed more sensitive to eutrophication impacts. The results will be used as part of the life cycle inventory (LCI) accounting for geographically explicit phosphorus flows. The waters identified as impaired were sourced from the …

Greenhouse Tomatoes: Process Simulation, Juan Gabriel Marin Jr.

Graduate Theses and Dissertations

Growing population demand and challenges brought on by climate change have spurred the need for more resilient fruit and vegetable supply chains. One agricultural technology of significant interest is the use of greenhouses for food production. Greenhouses create a stable and adaptable environment for crops such as tomatoes to grow year-round. Fresh tomatoes are the second most consumed vegetable per capita in U.S. diets, currently averaging 20.7 pounds. The growing consumption of fresh tomatoes has been the result of increasing cultural diversity in the United States.

To meet the growing demand, Venlo-type greenhouses have been frequently used by growers. It …

Developing A Lab-Scale Fluidized Bed Dryer System To Enhance Rough Rice Drying Process, Kaushik Luthra

Graduate Theses and Dissertations

For more than half of the world's population, rice (Oryza sativa L.) is a staple meal. However, rice growers encounter difficulties supplying this demand, particularly in developing nations, where rice is susceptible to spoilage if the moisture content is not lowered to a safe level soon after harvest. As a result, traditional drying methods, such as sun drying and natural air drying, are commonly used by rice growers, particularly in underdeveloped nations. However, these procedures are time-consuming and can lead to rice spoilage. On the other hand, fluidized bed drying is a well-established technology that might give rice growers a …

Economic And Ecosystem Impacts Of Gm Maize In South Africa, Kristiina Ala-Kokko

Graduate Theses and Dissertations

White maize in South Africa is the only staple crop produced on a widespread commercial basis for direct human consumption using genetically modified (GM) cultivars. Using a combined economic and environmental approach, we estimate the total welfare benefits attributable to GM white maize in South Africa for 2001-2018 are $694.7 million. Food security benefits attributable to GM white maize in South Africa also manifest through an average of 4.6 million additional white maize rations annually. To achieve these additional annual rations using conventional hybrid maize, the additional land required would range from 1,088 hectares in 2001 to 217,788 hectares in …

When It Rains, It Pours: A Case Study Of Spatio-Temporal Variations In High-Intensity Precipitation Events In Arkansas, Deanna Mantooth-Hendrix

Graduate Theses and Dissertations

Climate change is having an impact on weather systems and ecosystems worldwide. Glaciers are receding, oceans are acidifying, hurricanes are stronger, and extreme precipitation is increasing in frequency. Even with the wealth of data and knowledge about the threat of climate change, some places are slow to adapt because they think that the impact to their ecosystem will not be severe. The goal of this project was to determine if climate change is having an impact on extreme precipitation in the top urban areas of Arkansas. The major concern with an increase in extreme events in urban areas is flooding. …

Light Intensity Control For Plc-Based Hydroponic Demonstration System, Christian Hitt

Biological and Agricultural Engineering Undergraduate Honors Theses

In order to demonstrate a skill set obtained through the University of Arkansas Biological Engineering, a group of students and I developed a hydroponic system where plants could be grown in a chamber. System parameters such as air quality, irrigation, and lighting were controlled by a Programmable Logic Computer (PLC) and an array of sensors and actuators. Each student focused on a certain aspect of this system, mine being the lighting. Developing this system involved researching the relationship between light intensity and plant growth, designing a system to suspend the lights above the growth chamber, and develop a system to …

Estimating Irrigation In Rice Fields With A Water Balance Approach, Kristen Trinh

Biological and Agricultural Engineering Undergraduate Honors Theses

Global food production must increase to meet the demand associated with increased population growth, so irrigation water use will continue to rise. Therefore, it is important to monitor water usage particularly when an irrigation flowmeter is unavailable. A field water balance was created for a selection of rice fields in East-central Arkansas under observation in 2018 and 2019. From those, irrigation inputs are deduced from the water balance alone. First, each field had sensors that collected water table level (WTL) data. Next, other water inputs and outputs such as precipitation and evapotranspiration (ET) were collected from two modeled sources. The …

Design Of Control Logic And The Human-Machine Interface For A Demonstration Plant Growth Chamber Implemented On A Programmable Logic Controller, Rachael Koehler

Biological and Agricultural Engineering Undergraduate Honors Theses

This honors thesis covers the planning, development, and implementation of system controls and human-machine interface (HMI) for a demonstration plant growth chamber. The work is a continuation of an ongoing project to be used as an educational and recruiting tool manifesting the skills acquired from the Biological and Agricultural Engineering Department at the University of Arkansas’ College of Engineering. This work includes emergency controls, overall design interface, and controls for both the aeration and lighting subsystems of the growth chamber. Overall design interface controls established included development of two user modes, Administrator and Visitor. The Administrator user will have full …

Ventilation And Recirculation Airway Design For An Autonomous, Climate Controlled, Hydroponic Demonstration Unit, Nicholas Cross

Biological and Agricultural Engineering Undergraduate Honors Theses

For this Honors Thesis project, I designed and fabricated a ventilation and recirculation airway sub-system prototype for a hydroponic demonstration unit to be used as an educational demonstration for prospective students, illustrating the capabilities of biological engineers. This thesis focuses on the design of an autonomous air system that toggles between ventilation and recirculation modes based upon sensor output. In the literature review I discuss how ventilation can be used to achieve a targeted climate, the benefits of hands-on projects for education, and the optimum parameters for growing herbs in a hydroponic system.

In the design and fabrication process, every …

Design And Testing Of A Multi-Depth Soil Temperature Sensor Array Intended As A Candidate Irrigation Scheduling Tool, Lillian Glaeser

Biological and Agricultural Engineering Undergraduate Honors Theses

A crucial measure in the advancement of water conservation and sustainable agricultural strategies is increasing efficiencies of irrigation systems. Because of the lack of availability of affordable, durable, and scalable soil moisture monitoring devices, this thesis proposes a low-cost, multi-depth soil temperature sensor array as a candidate for monitoring soil moisture content and guiding farmer’s irrigation scheduling. Propagation of diurnal temperature waves through soil is dependent on the thermal diffusivity of the soil, which can be determined by examining temperature waves at different soil depths. Thermal diffusivity is dependent on several factors, though, in undisturbed soil, water has the largest …

Elucidating Basis Of Rice Discoloration And Developing Prevention Strategies, Zeinab Mohammadi Shad

Graduate Theses and Dissertations

Economically, discolored rice kernels have less market value, which can seriously impact farm net profit. The reasons for rice discoloration during storage have not been studied extensively and many questions remain. Therefore, the primary goal of this study was to improve understanding of the role and contributions of storage practices on rice quality degradation and discoloration. In this study, three rice cultivars including XL753 (hybrid), Roy J (pureline), and Titan were assessed for changes in quality and microbial kinetics. The rice samples at a high moisture content (MC) of 21% w.b. and a low MC of 16% were stored at …

The Release, Transport, And Utilization Of Phosphorus From Bed-Sediments: A Study Of A Eutrophic Littoral Cove On Beaver Lake In Northwest Arkansas, James A. Mccarty

Graduate Theses and Dissertations

Eutrophication of surface waters not only impacts the environment but also water treatment processes, the most significant of which is from the effects of algae. During peak algal growth in many southern U.S. reservoirs, inflows that bring nutrients are at an annual minimum, and phosphorus released from bed-sediments is trapped in the hypolimnion. Littoral areas, described as the most productive zone of the lake, may be a possible source of phosphorus that fuels algal growth in the reservoir. I studied an isolated shallow cove in the War Eagle Creek arm of Beaver Lake in Northwest Arkansas to measure, quantify, and …

Removal Of Fluoride From Mine Water Via Adsorption For Land-Applied Soil Amendment, Ethan Phan, Adrian Damian, Kevin Le, Mary Johnson, Courtney Golman, Michelle Dopp, Jacqueline Payne

Chemical Engineering Undergraduate Honors Theses

The process of mining minerals and elements from ores and rocks creates acid rock drainage (ARD). This drainage is water that contains heavy metals and minerals that can be dangerous for human consumption or damaging to the environment. The mining industry has employed various water treatment methods to prevent these metals and minerals from being discharged into water sources such as ponds, lakes, and streams. Currently, the most used treatment process in the mining industry is a cost-effective high-density sludge (HDS) process. This method reduces the concentration of metals and elements with the use of lime/limestone. However, the concentration of …