Master of Science, The Ohio State University, 2021, Horticulture and Crop Science

Many farmers typically regard wheat as a “low input” crop and expect low yields and low returns. Conversely, some farmers intensively manage wheat with many inputs and expect high yields and returns. The objective of this research was to identify inputs that improve wheat grain yield, straw yield, and economic return and reduce deoxynivalenol (DON) concentration in the grain. An incomplete factorial, omission trial was established at two locations in Ohio (South Charleston and Custar) during the 2019-2020 and 2020-2021 growing seasons. Treatments consisted of intensive management (IM) which received all inputs, a traditional management (TM), and the individual addition or removal each input from the TM or IM, respectively. The inputs were a high seeding rate, a high N rate, a split application of N, a spring sulfur application, a fungicide application at Feekes 9, and a fungicide application at Feekes 10.5.1. Intensive management increased grain yield at three of the site-years during this study by an average of 0.83 Mg ha-1. At the South Charleston location, in general, the use of a fungicide at either timing proved to be important for protecting yield. The addition of a fungicide at Feekes 10.5.1 to the TM significantly protected yield both years by an average of 0.66 Mg ha-1 and the removal of this fungicide from the IM significantly decreased yield by 0.63 Mg ha-1 in 2021. Additionally, at the same location the addition of a fungicide at Feekes 9 to the TM and the removal of a fungicide from the IM significantly changed yield in 2020 by 0.81 and -0.71 Mg ha-1. At Custar, only one treatment significantly changed yield in either year. In 2021, the removal of split N from the IM significantly reduced grain yield by 0.44 Mg ha-1. Straw yield was not consistently affected by any treatment in this study. DON concentration was significantly reduced by the IM at South Charleston both years due to the addition of a fungicide at Feekes 10.5.1. Intensive management did not (open full item for complete abstract)

Committee: Laura Lindsey (Advisor); Pierce Paul (Committee Member); Tim Haab (Committee Member) Subjects: Agricultural Economics; Agriculture; Agronomy

Master of Science, The Ohio State University, 2021, Welding Engineering

Nickel-base alloy corrosion resistant weld overlays (WOLs) are used in the oil and gas and petrochemical industry to protect against pipeline failure due to corrosion while also reducing costs. Currently, for some industry specific applications, these WOLs are produced using hot wire gas tungsten arc welding (HW-GTAW), a high heat input process. Per specifications such as API 5LD and DNV-OS-F101, additional iron content in the weld metal of nickel-base WOLs must be sufficiently reduced to ensure adequate corrosion resistance of the WOL. The amount of additional iron in the weld metal is a result of dilution of the clad layer by the substrate. High heat input processes such as HW-GTAW tend to produce welds with higher dilution, and as a result, up to three layers of weld metal are needed to sufficiently reduce iron content in the weld metal. Previous projects at OSU, addressing corrosion resistant WOLs in the nuclear industry, have demonstrated that low heat input gas metal arc welding (GMAW) processes, such as cold metal transfer (CMT), can produce WOLs with lower dilution, higher deposition rates, and greater corrosion resistance than similar overlays produced with HW-GTAW. However, concerns of lack of fusion and lack of penetration defects along with insufficient process optimization have hindered the widespread application of low heat input GMAW for WOLs. This study aimed to investigate the viability of CMT for production of WOLs for the oil and gas and petrochemical industry. Bead-on-plate welds of three nickel-base alloys (alloy 625, alloy 686, and alloy 825) were produced with CMT on low alloy steel X65 using a design of experiments approach. Bead geometry, heat input, deposition rate, and the presence of lack of penetration defects from each sample were measured and categorized to identify parameter sets that produced welds adhering to certain criteria such as low dilution, moderate toe angles, and lack of defects. Deposition rates for CMT were around 3 (open full item for complete abstract)

Committee: Boian Alexandrov Dr. (Advisor); Gerald Frankel Dr. (Committee Member) Subjects: Engineering; Materials Science

Master of Science, The Ohio State University, 2018, Electrical and Computer Engineering

This thesis presents work on the design of a 10 Kb, 500 MHz, self-timed, static random-access memory (SRAM) in the IBM8HP 0.13µm BiCMOS process. A high-speed SRAM architecture intended for fast caches, serial code accelerators, and high-speed processors was implemented and fabricated in the IBM8HP process. Simulation results show operation at above the targeted 500 MHz operating speed free of read-failure. A preliminary test plan has been developed, and measured results will be obtained for the memory from a printed circuit board (PCB) capable of measuring all of the pertinent characteristics. In addition to the fabricated SRAM design, a novel current-mode sense amplifier (CSA) topology has been proposed to work within the current architecture. Simulation results show up to a 30% reduction in the total read-access time (RDt) and thus a proportional improvement in the speed of the memory.

Committee: Waleed Khalil Dr. (Advisor); Steven Bibyk Dr. (Advisor) Subjects: Electrical Engineering

Master of Science, The Ohio State University, 2015, Horticulture and Crop Science

From 2000 to 2013 soybean [Glycine max (L.) Merr] grain commodity price has increased by almost 300% generating interest in agricultural inputs to maximize soybean yield. The objective of this study was to evaluate the effect of common inputs on soybean grain yield in enhanced (high-input) and traditional (low-input) production systems. The inputs evaluated included: Rhizobia inoculant, gypsum, pyraclostrobin fungicide, lambda-cyhalothrin insecticide, and manganese (Mn) foliar fertilizer. A sixteen site-year trial was established in Ohio during 2013 and 2014. Rhizobia inoculant was seed applied before planting, gypsum was applied at the VC growth stage (unrolled unifoliate leaves), and fungicide, insecticide, and Mn foliar fertilizer were applied at the R3 growth stage (initial pod development). Measurements of percent leaf area affected by foliar disease and insect defoliation and Mn and sulfur (S) concentration in leaves were collected at six site-years. The omission of pyraclostrobin from the enhanced production system significantly reduced yield in five of sixteen site-years by 0.21 to 0.79 Mg ha-1, but its addition to a traditional system increased yield significantly at only one of sixteen site-years by 0.47 Mg ha-1 Soybean yield was influenced by fungicide application when fields had disease present, above average yield (>3.5 Mg ha-1), and received >25 cm of precipitation in June and July. During 2013 and 2014, with established corn/soybean rotations, no S or Mn deficiencies, and minimal insect pressure, there were limited effects of inoculant, gypsum, insecticide, and Mn foliar fertilizer on grain yield. The data indicate a very small potential for high-input production systems to enhance crop yield without the presence of diseases, insects, or nutrient deficiencies. Knowledge of potential yield limiting factors is useful in identifying inputs that will increase soybean yield on a field by field basis.

Committee: Laura Lindsey (Advisor); Anne Dorrance (Committee Member); Jim Metzger (Committee Member) Subjects: Agriculture; Agronomy; Plant Pathology; Plant Sciences

Master of Science in Engineering (MSEgr), Wright State University, 2013, Electrical Engineering

Two novel techniques, feedback inverter loop and pull-down bridge, adopted for multiple-input multiple-output (MIMO) dynamic CMOS circuits have been proposed in this thesis. The pull-down bridge technique optimizes the area and power of a single stage MIMO dynamic CMOS circuits, and the feedback inverter loop (FIL) technique improves the speed of multiple-stage dynamic CMOS circuits. Applying the pull-down bridge to the MIMO dynamic CMOS seven segment decoder, it is shown that common paths of different outputs are shared and optimized, which accounts for 12% speed improvement, 48% power reduction, and 73% area saving, as compared to the conventional logic design. Next, an optimized 64-bit binary comparator implemented by mixed-static-dynamic CMOS with FILs is presented. After partitioning the conventional dynamic CMOS into a mixed-static-dynamic CMOS, optimizing transistor sizes and using the FILs on the critical paths, the proposed design achieves 60% speed improvement and 42% power reduction, as compared to the conventional 64-bit dynamic CMOS comparator.

Committee: Henry Chen Ph.D. (Advisor); Marian K. Kazimierczuk Ph.D. (Committee Member); Yan Zhuang Ph.D. (Committee Member) Subjects: Electrical Engineering

Master of Science (MS), Ohio University, 2000, Electrical Engineering & Computer Science (Engineering and Technology)

This thesis discusses the construction, modeling and control of an active optical system for Flexlab. Flexlab is a flexible structures control testbed on which modeling and control techniques can be researched and developed. The addition of the active optical system onto the flexible structure allows the testbed to represent a more complex system for study as well as providing a wider range of capabilities. The optical path established along the flexible structure is highly susceptible to disturbances in pointing and alignment. Thus, the end goal is to provide optical path stabilization using the active optical system. This thesis can be divided into three main sections. The first is a discussion of the hardware aspects of integrating the optical system into the existing Flexlab system. This involves a study of the high-speed steering mirror which is the active component of the optical system. The second section of the thesis is a discussion of model development of the optical system. A model is developed based on the geometry and layout of the optical path. Both multi-input, multi-output (MIMO) and single-input, single-output (SISO)models are developed. The third section of the thesis involves the development of a controller which provides disturbance rejection for the optical system. The closed-loop control effort is restricted to the SISO case. Once the controller is designed, it is implemented and the results are presented.

Committee: Dennis Irwin (Advisor) Subjects: