ABEN Doctoral Work
https://hdl.handle.net/10365/32463
2024-03-28T23:29:04ZDesign and Development of an Automatic Steering System for Agricultural Towed Implements
https://hdl.handle.net/10365/33512
Design and Development of an Automatic Steering System for Agricultural Towed Implements
Delavarpour, Nadia
While an auto steered tractor can improve the overall accuracy and efficiency of an operation, for operations that involve towing an implement, a significant portion of the efficiency reduction comes from uncontrolled motions of the towed implement. Therefore, there is a crucial need to study auto steering system for towed implement as well. In this study different requirements of an auto steering system for a towed implement were developed and studied. In this study the guiding performance of two local positioning sensors (Tactile and Ultrasonic sensors) under similar conditions were studied for reading different trajectories at different traveling speed. Furthermore, a fuzzy logic control algorithm was developed to continually generate correction steering signals and keep the tractor and towed implement within a certain boundary of the reference trajectory. Finally, the designed controller was implemented in a hardware-in-loop (HIL) system to analyze the performance of the controller in real world conditions.
The result of this study showed that although the local guidance sensors could locate the tractor or towed implement positions with respect to plant rows accurately, limitations to the performance of sensors were also observed in certain conditions. Sensors were prone to various noises and digital filters were required to apply to collected data. Data analysis showed that at lower speeds (less than 1.79 m/s) the accuracy of sensors was ±2 cm or better. The fuzzy logic controller improved the trajectory tracking accuracy at slow speeds (1-5 m/s) for following non-complex trajectories while no major improvements were achieved for complex trajectories at these speeds. Therefore, the controller had an acceptable accuracy following straight trajectory with negligible deviations at slow speeds. Moreover, experimental results showed that the hydraulic cylinder followed the controller signals with sufficient accuracy. During the experiment the angular displacements remained in the range of ±10˚ and never hit the constraint of maximum achievable angle, which was ±30˚. The satisfactory results showed that the designed automatic steering control system has a good tracking performance with a fast response, thus meeting the navigation control requirement of agricultural equipment to a certain extent.
2022-01-01T00:00:00ZRangeland Forage Growth Prediction, Logistics, Energy, and Economics Analysis and Tool Development Using Open-Source Software
https://hdl.handle.net/10365/32767
Rangeland Forage Growth Prediction, Logistics, Energy, and Economics Analysis and Tool Development Using Open-Source Software
Navaneetha Srinivasagan, Subhashree
Forage availability was crucial for livestock production across the United States. Rangelands occupied vast areas 31 % of land and were the primary source of forage for livestock. However, extreme climatic conditions such as drought affect rangeland forage production and pose a serious threat to the rangeland enterprise. This increases the need to monitor forage in vast rangelands and adapt to other measures such as cultivating or buying forage to balance demand and supply. Despite this need, resources (studies and tools) on rangeland forage monitoring and existing forage production, handling, and economics were scattered and scarce. Therefore, a comprehensive systematic literature review was performed to gather the current understanding of the technology and resources used for monitoring and economics of forage production. Remote sensing technologies were widely used in recent research for their ability to scout vast areas frequently and machine learning (ML) in successfully comprehending complex relationships. Forage production economics was predominantly available for alfalfa forage crop, but other crops and bale collection logistics during production were ignored. Bale collection using conventional tractor carrying 1 and 2 bales/trip (BPT) and automatic bale picker (8-23 BPT) was simulated mathematically and analyzed with open-source R software using realistic equipment turning scenarios. Fuel consumption based on aggregation distance for ABP decreased on average by 72 % and 53 % compared to the tractor with 1 and 2 BPT. A web-based calculator tool was developed using open-source HTML, CSS, and JavaScript software for forage economic analysis including more than 10 varieties of forage crops involving the economics of bale collection (tractor and ABP). Pasture biomass yield prediction was performed with R software using vegetation index (VI) and climate data through ML approaches. Recursive feature selection (RFE) and random forest (RF) model for forage yield emerged as the best methodology based on accuracy. A web-based interactive tool was developed using the Shiny package in R to accommodate “field-specific,” pasture-scale inputs for predicting biomass yield. In conclusion, these successful results demonstrate the possibility of using open-source software for simulating logistics, developing models, and building tools for forage monitoring and analyzing the economics of forage production.
2022-01-01T00:00:00ZProcess Development for Effective, Recoverable and Reusable Magnetic Nanobiocatalysts for Biomass Hydrolysis
https://hdl.handle.net/10365/32701
Process Development for Effective, Recoverable and Reusable Magnetic Nanobiocatalysts for Biomass Hydrolysis
Hammed, Ademola Monsur
Recovery and reuse of enzymes can reduce the high enzyme costs that are challenging for cellulosic biorefineries. Attaching enzymes to magnetic nanoparticles to make magnetic nanobiocatalysts (MNBCs) can facilitate enzyme recovery and reuse. One approach for MNBC synthesis is by attaching enzymes to flexible polymer molecules to form polymer-enzyme conjugates (PECs) which in turn can be attached to superparamagnetic iron-oxide nanoparticles (SPIONs). However, this approach can be complex and unscalable. The research objective is to develop a scalable process to produce effective, recoverable and reusable cellulolytic MNBCs.
PECs were produced and tested before incorporation into MNBCs in order to test efficacy and reusability. The effects of different biomass pretreatment methods, temperature, pH and solid loading on PEC efficacy were determined. Hydrolysis conditions affect PEC and free enzyme (FE) efficacy equally suggesting that attachment to the polymer did not interfere with substrate-enzyme interaction. PEC has higher efficacy than FE at higher substrate loading offering potential for processing more substrate per batch. The recovered PECs were effective for subsequent hydrolysis and reduced enzyme requirement to 40% of free enzyme needed in the first stage.
A tubular electrochemical system (TES), an electrochemical reactor containing electrolytes flowing through a cathode tube with an inner anode rod, was developed to overcome scalability and sustainability challenges of SPION synthesis. The effects of current density, electrolyte concentration, electrolyte feeding strategy, and flow rate on TES productivity and SPION characteristics were determined. TES productivity and SPION characteristics were both affected by the reaction conditions. Increasing electrolyte flow rate caused a decrease in average SPION size and size-distribution. The flow rate can be used to control SPION size distribution and shape. Gradual addition of more electrolyte resulted in 75% increase in SPION yield.
Silica coating of SPIONs improves SPION longevity and adsorption capacity. A single-step process for silica-coated SPION (Si-SPION) synthesis using TES was developed. The coating agent (Na2SiO3) concentration did not affect Si-SPION morphology, but increasing Na2SiO3 concentration reduces SPION productivity. The Si-SPIONs did not dissolve in an acidic environment for 48 h and were suitable support for MNBC synthesis. The MNBCs were recovered and reused four times.
2021-01-01T00:00:00ZOptimization of Methane Yield in Solid-State Anaerobic Co-Digestion of Dairy Manure and Corn Stover
https://hdl.handle.net/10365/32269
Optimization of Methane Yield in Solid-State Anaerobic Co-Digestion of Dairy Manure and Corn Stover
Ajayi-banji, Ademola
Sole dependence on fossil fuel and the concomitant environmental concerns could be minimized through the optimization of green energy generation from the growing volume of onfarm organic wastes. In this mesophilic study, green energy, mainly methane, was optimized through the solid-state anerobic co-digestion (SSAD) of two on-farm organic wastes (dairy manure with corn stover). Factors considered to achieve the improved methane yield under a total solids of 16% were particle size of corn stover (0.18 – 0.42 and 0.42 – 0.84 mm), alkaline pretreatment type (thermo-chemical and wet state), alkaline-pretreatment reagent (NaOH, NH4OH, and Ca(OH)2) used for the corn stover, and the magnetite nanoparticles(20, 50, and 75 mg/L) thereafter added to the treatment with highest methane yield. Kinetic models were used to describe some of the high methane yield as well as the environmental impact investigated with life cycle assessment. Results indicated that corn stover with particle size 0.42 - 0.84 mm blended with dairy manure under a C/N of 24 had the highest methane yield (106 L/ kgVS) under 60 days retention time. After pretreatment of the 0.42 - 0.84 mm corn stover with the three different alkaline reagents, methane yield improved under this wet state pretreatment relative to thermochemical. For instance, calcium pretreated corn stover blended with dairy manure (CaW) had the highest methane yield (176 L / kgVS) under a reduced retention time (79 days), overcame potential volatile fatty acids accumulation and digester upset relative to other pretreated treatments. Furthermore, addition of 20 mg of the nanoparticles to the CaW treatment further enhanced methane yield (191 L / kg VS), minimized digester upset, and reduced retention time to 52 days. Suitable process parameters for methanogenic activities were 0.1 - 0.5 for VFA/Ammonia and VFA/Alkalinity ratios. Free ammonia concentration between 258 – 347 mg/L does not affect methanogenic activities. Environmnetal impact aseessment indicated that pretreatment negatively influenced human health factors and eutrophication potentials though reduced ozone depletion, global warming potential, and smog potentials. The solid-state of dairy manure co-digested with corn stover has the potential to improve green energy generation that could complement fossil fuel and address waste management challenges.
2020-01-01T00:00:00Z