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Full-Text Articles in Bioresource and Agricultural Engineering

Assessment Of The Effects Of Airflow Conditions Related To Hop Drying, David Mabie Aug 2021

Assessment Of The Effects Of Airflow Conditions Related To Hop Drying, David Mabie

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Hops have been utilized by brewers for centuries to contribute bitterness, antimicrobial preservation and desirable aromatic profiles to beer. The hop cone is a small, lightweight, high moisture content flower which produces lupulin glands containing resins and essential oils that contribute desirable characteristics to beer. Due to the high harvest moisture content (75% wet basis), hops must be rapidly dried to properly preserve them for future processing and brewing. While hops have been dried for centuries, most literature from the past century has focused on drying to minimizing loss to the resin or physical cone structure. The objectives of this …


Quantifying Hydrologic Pathway And Source Connectivity Dynamics In Tile Drainage: Implications For Phosphorus Concentrations, Saeid Nazari, William I. Ford, Kevin W. King Aug 2021

Quantifying Hydrologic Pathway And Source Connectivity Dynamics In Tile Drainage: Implications For Phosphorus Concentrations, Saeid Nazari, William I. Ford, Kevin W. King

Biosystems and Agricultural Engineering Faculty Publications

Flowpathways and source water connectivity dynamics are widely recognized to affect tile-drainage water quality. In this study, we developed and evaluated a framework that couples event-based hydrograph recession and specific conductance end-member mixing analysis (SC-EMMA) to provide a more robust framework for quantifying both flow pathway dynamics and source connectivity of drainage water in tile-drained landscapes. High-frequency (30-min) flow and conductivity data were collected from an edge-of-field tile main located in northwestern Ohio, and the newly developed framework was applied for data collected in water year 2019. Multiple linear regression (MLR) analysis was used to evaluate the impact of pathway-connectivity …


Methane Emission Treatment And Potential Upcycling Using Methylomicrobium Alcaliphilum, Jace Parkinson Aug 2021

Methane Emission Treatment And Potential Upcycling Using Methylomicrobium Alcaliphilum, Jace Parkinson

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Anthropogenic methane emissions are harmful to the environment and can be difficult to treat. Use of M. alcaliphilum for bioremediation of methane looks to be one of the most promising methods of reducing the negative environmental impacts of methane emissions while simultaneously providing an economic incentive. Successful bioreactor design for M. alcaliphilum based methane treatment requires biokinetic constants and microbial growth information. Methods were established for determining biokinetic constants, including growth rate, biomass yield, specific methane consumption rate, and a correlation between methane oxidation and carbon dioxide production for M. alcaliphilum. Values determined for these constants were used to …


Development Of Tractor Instrumentation System: Hydraulics, And Controller Area Network (Can) Data Analysis Of Agricultural Machinery, Chee Town Liew Aug 2021

Development Of Tractor Instrumentation System: Hydraulics, And Controller Area Network (Can) Data Analysis Of Agricultural Machinery, Chee Town Liew

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The tractor is a very important piece of machinery in agriculture, and it has been evolving and progressing over the years with improved and increasingly complex functionality. Controller Area Network (CAN) has been incorporated into tractors and other machinery with SAE J1939 and ISO 11783 standards, serving as the communication bus for various on-board electronic controller units (ECUs), and carries various machine operation data that can be used for analyzing machine performance. Investigation of data extraction from CAN messages was conducted by examining the SAE J1939 and ISO 11783 standards. A case study on CAN bus data analysis for a …


Tractor Instrumentation System: Hitch And Pto, And Row Crop Tractor Electrification Considerations, Andrew Donesky Aug 2021

Tractor Instrumentation System: Hitch And Pto, And Row Crop Tractor Electrification Considerations, Andrew Donesky

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Power sources used for vehicles are advancing at a fast pace. Electric batteries are becoming more power dense, thus allowing them to be used with electric motors in place of a diesel or gas powered systems. There are several ways that energy use and storage size can be computed for agricultural field operations, such as planting, using theoretical predictions, gathering engine load data from tractor’s Controller Area Network (CAN) bus, or integrating the CAN data to determine the actual power used by implements.

While measuring data from the CAN bus is a great way to capture actual tractor use information, …


Efficient Polyhydroxyalkanoate Production By Rhodopseudomonas Palustris From Lignocellulosic Biomass, Brandi Brown Jul 2021

Efficient Polyhydroxyalkanoate Production By Rhodopseudomonas Palustris From Lignocellulosic Biomass, Brandi Brown

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Polyhydroxyalkanoates (PHAs) are biopolymers produced by bacteria with the potential to replace conventional plastics. However, the relatively high production costs of PHAs are keeping them from market acceptance, with approximately half of the production costs derived from the feedstock. Thus, engineering a microbe for PHA production from cheaper and renewable carbon sources is necessary to promote the valorization of PHAs. Lignocellulosic biomass is considered to be one of the most economic carbon sources in the world, and is thus an attractive candidate for cheaper production of bioplastics. Rhodopseudomonas palustris CGA009 is a metabolically robust bacterium capable of catabolizing lignin breakdown …


Leveraging Unmanned Aerial System Remote Sensing To Inform Energy And Water Balance Models For Spatial Soil Water Content Monitoring And Irrigation Management, Mitchell S. Maguire Jul 2021

Leveraging Unmanned Aerial System Remote Sensing To Inform Energy And Water Balance Models For Spatial Soil Water Content Monitoring And Irrigation Management, Mitchell S. Maguire

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Irrigation has provided a means to produce more food and fiber throughout the world, converting low producing land into high yielding cropping systems in certain scenarios. The managing of irrigation has taken on various approaches as different locations have been constrained by different factors. Certain areas have significant ground and surface water available for irrigation while other areas struggle to meet irrigation demands due to limited water resources. These factors, along with the desire to increase crop water use efficiency, has provided the motivation to better understand crop water demands spatially within a field. A sub-field scale irrigation management study …


What About The Rest Of Them? Fatal Injuries Related To Production Agriculture Not Captured By The Bureau Of Labor Statistics (Bls) Census Of Fatal Occupational Injuries (Cfoi), Bryan Weichelt, Erika Scott, Rick Burke, John Shutske, Serap Gorucu, Wayne T. Sanderson, Murray Madsen, Emily Redmond, Dennis J. Murphy, Risto Rautiainen Jul 2021

What About The Rest Of Them? Fatal Injuries Related To Production Agriculture Not Captured By The Bureau Of Labor Statistics (Bls) Census Of Fatal Occupational Injuries (Cfoi), Bryan Weichelt, Erika Scott, Rick Burke, John Shutske, Serap Gorucu, Wayne T. Sanderson, Murray Madsen, Emily Redmond, Dennis J. Murphy, Risto Rautiainen

Biosystems and Agricultural Engineering Faculty Publications

Surveillance of injuries in production agriculture is necessary to inform stakeholders about workplace hazards and risks in order to improve and advance injury prevention policies and practices for this dangerous industry. The most comprehensive fatal injury surveillance effort currently in the United States is the Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries (CFOI), which covers occupational fatalities in all U.S. industries, including production agriculture. However, this surveillance does not include many categories of fatalities that occur during agricultural work or on production agriculture worksites. To better capture the human cost of production agriculture, the authors of this …


Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed Jul 2021

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …


Oxygen Reactive Polymers For Treatment Of Traumatic Brain Injury, Parick S. Stayton, Menko P. Ypma, Peter A. Chiarelli, Joshua Sang Hun Park, Richard G. Ellenbogen, Julia Mengyun Xu, Pierre D. Mourad, Donghoon Lee, Anthony Convertime, Forrest M. Kievit Jul 2021

Oxygen Reactive Polymers For Treatment Of Traumatic Brain Injury, Parick S. Stayton, Menko P. Ypma, Peter A. Chiarelli, Joshua Sang Hun Park, Richard G. Ellenbogen, Julia Mengyun Xu, Pierre D. Mourad, Donghoon Lee, Anthony Convertime, Forrest M. Kievit

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Methods and compositions for treating traumatic brain injury . The methods and compositions utilize a multi - functional oxygen reactive polymer ( ORP ) that includes repeating units that include a reactive oxygen species ( ROS ) scavenging group and a polyalkylene oxide group . For theranostic applications , the oxygen reactive polymer fur ther includes a diagnostic group .


Lessons To Be Learned In Adoption Of Autonomous Equipment For Field Crops, James Lowenberg-Deboer, Karl Behrendt, Melf-Hinrich Ehlers, Carl R. Dillon, Andreas Gabriel, Iona Yuelu Huang, Ian Kumwenda, Tyler Mark, Andreas Meyer-Aurich, Gabor Milics, Kehinde Oluseyi Olagunju, Søren Marcus Pedersen, Jordan M. Shockley, David Rose Jul 2021

Lessons To Be Learned In Adoption Of Autonomous Equipment For Field Crops, James Lowenberg-Deboer, Karl Behrendt, Melf-Hinrich Ehlers, Carl R. Dillon, Andreas Gabriel, Iona Yuelu Huang, Ian Kumwenda, Tyler Mark, Andreas Meyer-Aurich, Gabor Milics, Kehinde Oluseyi Olagunju, Søren Marcus Pedersen, Jordan M. Shockley, David Rose

Agricultural Economics Faculty Publications

Autonomous equipment for crop production is on the verge of technical and economic feasibility, but government regulation may slow its adoption. Key regulatory issues include requirements for on-site human supervision, liability for autonomous machine error, and intellectual property in robotic learning. As an example of the impact of regulation on the economic benefits of autonomous crop equipment, analysis from the United Kingdom suggests that requiring 100% on-site human supervision almost wipes out the economic benefits of autonomous crop equipment for small and medium farms and increases the economies-of-scale advantage of larger farms.


Response-To-Failure Analysis Of Global Food System Initiatives: A Resilience Perspective, Prince Agyemang, Ebenezer Miezah Kwofie Jul 2021

Response-To-Failure Analysis Of Global Food System Initiatives: A Resilience Perspective, Prince Agyemang, Ebenezer Miezah Kwofie

Biological and Agricultural Engineering Faculty Publications and Presentations

International food system initiatives have led the efforts to combat the threats to global food security resulting from the failure of the current food systems. This study set out to investigate and assess the contributions of global food system initiatives in tackling the food system challenges. In assessing the food system initiatives, we develop a three-step methodology for Food System Initiative (FSI) selection and then conduct a qualitative evaluation using relevant indicators based on food system failure narratives. Furthermore, the authors synthesize present literature in the context of the extent to which coronavirus disease 2019 (COVID-19) pandemic has compounded food …


Developing A Lab-Scale Fluidized Bed Dryer System To Enhance Rough Rice Drying Process, Kaushik Luthra Jul 2021

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 …


Sensor-Based Irrigation Of Maize And Soybean In East-Central Nebraska Under A Sub-Humid Climate, Jasreman Singh, Derek M. Heeren, Yufeng Ge, Geng Bai, Christopher M.U. Neale, Mitchell S. Maguire, Sandeep Bhatti Jul 2021

Sensor-Based Irrigation Of Maize And Soybean In East-Central Nebraska Under A Sub-Humid Climate, Jasreman Singh, Derek M. Heeren, Yufeng Ge, Geng Bai, Christopher M.U. Neale, Mitchell S. Maguire, Sandeep Bhatti

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The ever increasing pressure on the water resources in Nebraska and other irrigated agricultural areas require innovations and solutions for the governance of water allocation. This study proposes the use of sensor-based method for irrigation which has the potential to improve irrigation water use efficiency (IWUE). Practical methods and algorithms for creating irrigation prescriptions have become vital for the adoption of precision irrigation. A decision support system (DSS) for uniform irrigation was evaluated during 2020 growing season in a sub-humid region. The DSS was managed using soil water and plant feedback. In field practice, a sensor node station comprising of …


Impact Of Irrigation Technologies On Withdrawals And Consumptive Use Of Water, Eric Wilkening, Derek M. Heeren, Douglas R. Hallum, Jennifer Schellpeper, Derrel Martin Jul 2021

Impact Of Irrigation Technologies On Withdrawals And Consumptive Use Of Water, Eric Wilkening, Derek M. Heeren, Douglas R. Hallum, Jennifer Schellpeper, Derrel Martin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Developments in irrigation technologies have subsequently led to increases in irrigation application efficiency, including conversion from surface to sprinkler irrigation, variable rate irrigation (VRI), and low energy precision application. However, while these increases in application efficiency may reduce water withdrawals and/or diversions (from groundwater or surface water), they may not necessarily translate to additional water being available for future or downstream use. Consumptive use of water, water consumed and not returned to the local or sub-regional watershed, is not necessarily impacted by increased application efficiency, but is an important metric in conserving water for other uses. One recent irrigation technology …


Development Of Yam-Starch-Based Bioplastics With The Addition Of Chitosan And Clove Oil, Ulyarti Ulyarti, Lavlinesia Lavlinesia, Surhaini Surhaini, Nurainun Siregar, Anggel Tomara, Lisani Lisani, Nazarudin Nazarudin Jun 2021

Development Of Yam-Starch-Based Bioplastics With The Addition Of Chitosan And Clove Oil, Ulyarti Ulyarti, Lavlinesia Lavlinesia, Surhaini Surhaini, Nurainun Siregar, Anggel Tomara, Lisani Lisani, Nazarudin Nazarudin

Makara Journal of Science

The potency of yam starch (Dioscorea alata) as film-forming material together with the potency of chitosan and clove oil as antibacterial materials has led the authors to produce active bioplastics based on these materials. This research was performed to determine the effect of chitosan and clove oil on the physical, mechanical, and barrier properties of yam starch’s active bioplastics. The best bioplastics produced were further tested for their antimicrobiological properties. This study used a completely randomized design with five levels of chitosan concentration (1%, 1.2%, 1.4%, 1.6%, and 1.8%) and five levels of clove oil concentration (0.3%, 0.6%, …


Creating A Field-Wide Forage Canopy Model Using Uavs And Photogrammetry Processing, Cameron Minch, Joseph S. Dvorak, Joshua J. Jackson, Stuart Tucker Sheffield Jun 2021

Creating A Field-Wide Forage Canopy Model Using Uavs And Photogrammetry Processing, Cameron Minch, Joseph S. Dvorak, Joshua J. Jackson, Stuart Tucker Sheffield

Biosystems and Agricultural Engineering Faculty Publications

Alfalfa canopy structure reveals useful information for managing this forage crop, but manual measurements are impractical at field-scale. Photogrammetry processing with images from Unmanned Aerial Vehicles (UAVs) can create a field-wide three-dimensional model of the crop canopy. The goal of this study was to determine the appropriate flight parameters for the UAV that would enable reliable generation of canopy models at all stages of alfalfa growth. Flights were conducted over two separate fields on four different dates using three different flight parameters. This provided a total of 24 flights. The flight parameters considered were the following: 30 m altitude with …


Robotic Technologies For High-Throughput Plant Phenotyping: Contemporary Reviews And Future Perspectives, Abbas Atefi, Yufeng Ge, Santosh Pitla, James Schnable Jun 2021

Robotic Technologies For High-Throughput Plant Phenotyping: Contemporary Reviews And Future Perspectives, Abbas Atefi, Yufeng Ge, Santosh Pitla, James Schnable

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Phenotyping plants is an essential component of any effort to develop new crop varieties. As plant breeders seek to increase crop productivity and produce more food for the future, the amount of phenotype information they require will also increase. Traditional plant phenotyping relying on manual measurement is laborious, time-consuming, error-prone, and costly. Plant phenotyping robots have emerged as a high-throughput technology to measure morphological, chemical and physiological properties of large number of plants. Several robotic systems have been developed to fulfill different phenotyping missions. In particular, robotic phenotyping has the potential to enable efficient monitoring of changes in plant traits …


Comparison Of Promoter, Dna Vector, And Cationic Carrier For Efficient Transfection Of Hmscs From Multiple Donors And Tissue Sources, Tyler Kozisek, Andrew Hamann, Luke Samuelson, Miguel Fudolig, Angela K. Pannier Jun 2021

Comparison Of Promoter, Dna Vector, And Cationic Carrier For Efficient Transfection Of Hmscs From Multiple Donors And Tissue Sources, Tyler Kozisek, Andrew Hamann, Luke Samuelson, Miguel Fudolig, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Human mesenchymal stem cells (hMSCs) are primary cells with high clinical relevance that could be enhanced through genetic modification. However, gene delivery, particularly through nonviral routes, is inefficient. To address the shortcomings of nonviral gene delivery to hMSCs, our lab has previously demonstrated that pharmacological “priming” of hMSCs with clinically approved drugs can increase transfection in hMSCs by modulating transfection-induced cytotoxicity. However, even with priming, hMSC transfection remains inefficient for clinical applications. This work takes a complementary approach to addressing the challenges of transfecting hMSCs by systematically investigating key transfection parameters for their effect on transgene expression. Specifically, we investigated …


Center Pivot Project Specifications, Charles M. Burt Jun 2021

Center Pivot Project Specifications, Charles M. Burt

BioResource and Agricultural Engineering

This note provides an example of items that are included in a specification for center pivots. It is a supplement to design drawings that have numerous additional details. This example combines items from various ITRC jobs, and therefore the units are not consistent (there is a mix of metric and English units). The intention, however, is not to provide a precise specification that can be replicated, but rather to show the key items that are typically included.

In such projects, there are two primary sets of specifications:

  • The details of the center pivots themselves and warranties for the pivots
  • The …


Computational Prediction Of Mutagenesis In Glycine Max Rubisco Activase Monomer For Increased Thermal Stability, Catherine B. Emanuel, Hamza Haq '21, Vasanth Ramesh '21, Jaden Wang '21, Angela Ahrendt, Sarah Stainbrook Jun 2021

Computational Prediction Of Mutagenesis In Glycine Max Rubisco Activase Monomer For Increased Thermal Stability, Catherine B. Emanuel, Hamza Haq '21, Vasanth Ramesh '21, Jaden Wang '21, Angela Ahrendt, Sarah Stainbrook

Student Publications & Research

No abstract provided.


Modeling Vadose Zone Hydrology [Lecture Notes], Derek M. Heeren, Dean E. Eisenhauer Jun 2021

Modeling Vadose Zone Hydrology [Lecture Notes], Derek M. Heeren, Dean E. Eisenhauer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Modeling Vadose Zone Hydrology is a graduate-level course offered biennially in the Department of Biological Systems Engineering. Topics included hydraulic properties of porous media, application of Darcy's Law in variably saturated media, hydrologic and transport processes in the vadose zone, and solution of steady and unsteady flow problems using numerical techniques. A graphical approach for characterizing vertical one-dimensional problems with energy head profiles was emphasized. Common one-dimensional flow and transport problems were solved analytically. The course was taught using a combination of lecture notes and PowerPoint presentations. The lecture notes from 2021, captured using the Microsoft Whiteboard app with a …


Uavs For Vegetation Monitoring: Overview And Recent Scientific Contributions, Ana I. De Castro, Yeyin Shi, Joe Mari Maja, Jose M. Peña May 2021

Uavs For Vegetation Monitoring: Overview And Recent Scientific Contributions, Ana I. De Castro, Yeyin Shi, Joe Mari Maja, Jose M. Peña

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This paper reviewed a set of twenty-one original and innovative papers included in a special issue on UAVs for vegetation monitoring, which proposed new methods and techniques applied to diverse agricultural and forestry scenarios. Three general categories were considered: (1) sensors and vegetation indices used, (2) technological goals pursued, and (3) agroforestry applications. Some investigations focused on issues related to UAV flight operations, spatial resolution requirements, and computation and data analytics, while others studied the ability of UAVs for characterizing relevant vegetation features (mainly canopy cover and crop height) or for detecting different plant/crop stressors, such as nutrient content/deficiencies, water …


Early Detection Of Encroaching Woody Juniperus Virginiana And Its Classification In Multi-Species Forest Using Uas Imagery And Semantic Segmentation Algorithms, Lin Wang, Yuzhen Zhou, Qiao Hu, Zhenghong Tang, Yufeng Ge, Adam Smith, Tala Awada, Yeyin Shi May 2021

Early Detection Of Encroaching Woody Juniperus Virginiana And Its Classification In Multi-Species Forest Using Uas Imagery And Semantic Segmentation Algorithms, Lin Wang, Yuzhen Zhou, Qiao Hu, Zhenghong Tang, Yufeng Ge, Adam Smith, Tala Awada, Yeyin Shi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Woody plant encroachment into grasslands ecosystems causes significantly ecological destruction and economic losses. Effective and efficient management largely benefits from accurate and timely detection of encroaching species at an early development stage. Recent advances in unmanned aircraft systems (UAS) enabled easier access to ultra-high spatial resolution images at a centimeter level, together with the latest machine learning based image segmentation algorithms, making it possible to detect small-sized individuals of target species at early development stage and identify them when mixed with other species. However, few studies have investigated the optimal practical spatial resolution of early encroaching species detection. Hence, we …


Exploration Of The Sludge Biodiesel Pathway, Zachary Christman May 2021

Exploration Of The Sludge Biodiesel Pathway, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater sludge is an overlooked source of fat, oil, and grease (FOG) that could be converted into biodiesel. The United States produces about 8 million tons of sludge per year. The disposal cost for this amount of sludge is about 2 billion US dollars. The widespread availability and low cost of sludge compared to other biodiesel raw materials make it an economical choice for a renewable fuel. Using sludge as a raw material can produce 25 to 30 mg per gram of fatty acid methyl ester (FAME); the main component of biodiesel. Sludge biodiesel has the potential of transforming a …


Assessment And Improvement Of Performance Of Septic Systems In Cold Climates (Year 1), Stu Geza, Todd Menkhaus, Lianping Li, Galen Hoogestraat May 2021

Assessment And Improvement Of Performance Of Septic Systems In Cold Climates (Year 1), Stu Geza, Todd Menkhaus, Lianping Li, Galen Hoogestraat

SDWRI Publications and Reports

Onsite septic systems are used for wastewater treatment for households not connected to sewers. There is a concern about surface and groundwater pollution when effectiveness becomes limited due to soil texture, soil temperature, neighborhood density, and distance to water resources. The goal of this study was to assess treatment performance of local soils and selected treatment media. Lab-scale column experiments were conducted using wastewater from Wastewater Reclamation Facility in Rapid City. The experiments were conducted inside and outside the lab to evaluate the effect of temperature. The columns outside the lab were subject to seasonal variation in temperature. Moisture content, …


Economic And Ecosystem Impacts Of Gm Maize In South Africa, Kristiina Ala-Kokko May 2021

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 …


Light Intensity Control For Plc-Based Hydroponic Demonstration System, Christian Hitt May 2021

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 …


Control System For Variable-Orifice Mechatronic Spray Nozzle For Regulation Of Application Rate And Droplet Size Spectra, Rodney Rohrer May 2021

Control System For Variable-Orifice Mechatronic Spray Nozzle For Regulation Of Application Rate And Droplet Size Spectra, Rodney Rohrer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Traditional fixed-orifice spray nozzles are selected for flow rate and droplet spectra required for a given pesticide application. Although limited variation in flow can be achieved by adjusting system pressure, this can adversely affect spray quality. Other nozzle configurations, such as Pulse Width Modulated (PWM) nozzles or passive variable-orifice designs, are intended to maintain consistent droplet size and spray pattern as flow rate is changed but those too have limitations.

A variable-orifice nozzle modified by Luck (2012) can span multiple droplet spectra and offers independent control of flow and droplet size; however, an advanced control system must be developed to …


Sensor-Based Nitrogen Management On Non-Irrigated Corn Based Systems In Nebraska, Samantha L. Teten May 2021

Sensor-Based Nitrogen Management On Non-Irrigated Corn Based Systems In Nebraska, Samantha L. Teten

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Optimizing nitrogen (N) fertilizer applications in corn to reduce environmental impacts while maintaining producer profitability remains a challenge due to spatial and temporal variability in crop yield potential and soil N dynamics. In response to these challenges, active crop canopy sensors and imagery systems have been studied to test the performance of vegetative index-based N management, but adoption has been low. There is also a lack of field-scale research evaluating this technology in water-limiting environments.

The evaluation of two sensor-based N management techniques was completed at nine non-irrigated sites in Eastern Nebraska. The first sensor-based N management technique evaluated an …