HIGH-THROUGHPUT PHENOTYPING THAT IMPROVES THE EFFICIENCY OF A COTTON PLANT BREEDING SYSTEM

Unmanned Aerial Vehicles (UAVs) play an important role in agricultural research because they facilitate high-throughput phenotyping (HTP). Cotton (Gossypium spp.) is the world’s leading natural textile fiber crop, and breeding programs that enhance the efficiency of growing the crop are important to the viability of the cotton industry. The effectiveness of plant breeding programs is improved when researchers have the ability to quickly evaluate important traits in a field environment. The ability to identify cotton plant height and boll count across a field can serve as an important tool in predicting plant growth and yield. In order to capture a three-dimensional (3D) view of field plots, which is believed to be helpful in estimating yield and crop development parameters, sensors mounted on UAVs must have access to a view of the ground. However, cotton planted in solid rows can obscure this view. Canopy closure prevents sensors from measuring plant architecture and boll-loads three dimensionally from the mid-growing season until the crop is defoliated. Therefore, this project was initiated to compare solid vs. skip-row planting patterns in terms of predicting yield and fiber quality since skip rows would allow UAV sensors to capture more accurate 3D data from plots. The purposes of this project were to (1) use UAVs to characterize genotype x row pattern interaction and how location and year affect that interaction, (2) evaluate the ability of UAVs to predict plant height and yield, (3) compare the accuracy of UAV-derived data from different planting patterns and (4) use images processed from UAVs to standardize data for every single row to predict yield performance. Two UAVs were used for red, green, and blue (RGB) data collection and multispectral data collection. Five cotton genotypes were grown in a skip versus solid row pattern at three locations in 2017 and 2018. Yield and fiber qualities were measured for all treatments. UAVs were flown across the field bi-weekly to estimate plant height, canopy cover, canopy volume, vegetation indices, open boll count and boll area over different growing stages. Without extreme weather influence, lint yield and fiber quality were not affected by Genotype X row-spacing effects. Also, year and location did not influence that interaction. In addition, yield and plant height estimations were improved when cotton was planted in a skip-row pattern. Single row rating based on orthomosaic images and 3D point cloud images correlated with yield performance. Therefore, to take full advantage of UAV data, cotton breeding programs need to plant early generation lines (progeny rows) in skip rows that allow sensors to have access to the view of the ground and capture 3D images. This can be accomplished without compromising the efficiency and accuracy of the breeding program

Piezotronic devices and integrated systems

Novel technology which can provide new solutions and enable augmented capabilities to CMOS based technology is highly desired. Piezotronic nanodevices and integrated systems exhibit potential in achieving these application goals. By combining laser interference lithography and low temperature hydrothermal method, an effective approach for ordered growth of vertically aligned ZnO NWs array with high-throughput and low-cost at wafer-scale has been developed, without using catalyst and with a superior control over orientation, location/density and morphology of as-synthesized ZnO NWs. Beyond the materials synthesis, by utilizing the gating effect produced by the piezopotential in a ZnO NW under externally applied deformation, strain-gated transistors (SGTs) and universal logic operations such as NAND, NOR, XOR gates have been demonstrated for performing piezotronic logic operations for the first time. In addition, the first piezoelectrically-modulated resistive switching device based on piezotronic ZnO NWs has also been presented, through which the write/read access of the memory cell is programmed via electromechanical modulation and the logic levels of the strain applied on the memory cell can be recorded and read out for the first time. Furthermore, the first and by far the largest 3D array integration of vertical NW piezotronic transistors circuitry as active pixel-addressable pressure-sensor matrix for tactile imaging has been demonstrated, paving innovative routes towards industrial-scale integration of NW piezotronic devices for sensing, micro/nano-systems and human-electronics interfacing. The presented concepts and results in this thesis exhibit the potential for implementing novel nanoelectromechanical devices and integrating with MEMS/NEMS technology to achieve augmented functionalities to state-of-the-art CMOS technology such as active interfacing between machines and human/ambient as well as micro/nano-systems capable of intelligent and self-sufficient multi-dimensional operations.Ph.D

Fabrication, characterization and analysis of carbon nanotube based nanoelectromechanical system

Master'sMASTER OF ENGINEERIN

Novel Approaches to Weed Management: Exploiting Breeding System Handicaps in Dioecious Species with a Focus on Palmer Amaranth (Amaranthus palmeri)

The success of the Insect Sterile Technique (IST) in managing insect pests raised the hypothesis that a similar approach could be employed to control weed populations. This research delved into the potential of using irradiated sterile pollen to disrupt seed production in dioecious weeds, with a focus on Palmer amaranth (Amaranthus palmeri S. Watson). The overall objective this project is to understand the reproductive biology of dioecious weeds and to examine the possibility of using sterile pollen to disrupt seed production in dioecious weeds. In Chapter 1, we characterized phases of flower development in A. palmeri and compared organogenesis of flower development in female and male plants. Understanding the reproductive biology of this species is crucial for guiding the development of novel weed management strategies, as it enables the identification of specific vulnerabilities that can be targeted to disrupt seed production. Results showed the distinction between the two flower types became apparent at stage four by the formation of stamen primordia in staminate flowers, which developed both the female and male reproductive organs initially, as contrasted to pistillate flowers which produced carpel primordia only. Our study suggests that the evolution of A. palmeri from a cosexual ancestral to complete dioecy is still in progress. Chapter 2 examined the optimal irradiation dose to reduce seed production in A. palmeri. An irradiation dose of 300 Gy seems to be the most effective in reducing seed set in Palmer amaranth. Furthermore, the greatest reduction in seed set was achieved when irradiated pollen was introduced to the stigma through artificial pollination prior to open pollination. It appears that irradiated pollen exerts a preventive effect on naturally occurring pollen that arrives later. Furthermore, in order to increase the efficiency of SPT applications, Chapter 3 focused on investigating an ideal dry (inert) diluent and a most effective mix ratio of pollen/diluent and identifying the optimal strategy of sterile pollen applications to minimize seed production in Palmer amaranth. The findings showed that the optimal formulation was a 25%/75% mixture of irradiated pollen and talc powder by volume, successfully reducing seed set in A. palmeri while efficiently utilizing the limited resource of irradiated pollen. The most effective application strategy was initiating the application 7 days after anthesis and repeating it three times at 7-day intervals. This study also addressed the potential trade-off between inflorescence growth and fertilization rate, hypothesizing that high fertilization could divert resources away from inflorescence development to seed production. We found massive pollination of irradiated pollen or non-irradiated pollen did not have an effect on inflorescence growth, but it did on the sex ratio in the progeny population, resulting in female-biased progeny as predicted by certation theory

Wearable Piezotronic Devices for Heart Rate Monitoring

Self-powered multifunctional wearable devices that are capable of human-device interfacing are highly desired. Piezotronic devices utilize piezoelectricity and semiconductor properties to enable devices to have seamless interaction between human and device. One important use for piezotronic devices is for pressure sensing. Pressure sensing devices have been employed in smart skins, biomonitoring, gesture recognition, and many more applications. This study aims to create a flexible piezotronic device, specifically for use in pressure sensing to monitor heart rate. ZnO nanowires are grown on a flexible polymer substrate so that they can be made into wearable devices. A p-n heterojunction is formed by depositing a layer of p-type tellurium nanowire on top of the ZnO nanowires. These wearable devices are capable of performing the above mentioned tasks through the piezotronic effect that effectively modulates the electronic transport through the p-n junction. One function in particular is heart rate monitoring. This could be an extremely useful and minimally invasive way of detecting heart diseases such as arrhythmia

Tellurium: Fast Electrical and Atomic Transport along Weak Interaction Direction

In anisotropic materials, the electrical and atomic transport along the weak interaction direction is usually much slower than that along the chemical bond direction. However, Te, an important semiconductor comprised of helical atomic chains, exhibits nearly isotropic electrical transport between intra-chain and inter-chain directions. Using first-principles calculations to study the bulk and few-layer Te, we show that this isotropy is related with similar effective mass and potential for charge carriers along different transport directions, benefiting from the delocalization of the lone-pair electrons. This delocalization also enhances the inter-chain binding, although it is still significantly weaker than the covalent intra-chain bonding. Moreover, we find a fast diffusion of vacancies and interstitial atoms along and across the chains, enabling rapid self-healing of these defects at room temperature. Interestingly, the interstitial atoms diffuse along the chain via a concerted-rotation mechanism. Our work reveals the unconventional properties underlying the superior performance of Te, while providing insight into the transport in anisotropic materials

Quantum Transport and Band Structure Evolution under High Magnetic Field in Few-Layer Tellurene

Quantum Hall effect (QHE) is a macroscopic manifestation of quantized states which only occurs in confined two-dimensional electron gas (2DEG) systems. Experimentally, QHE is hosted in high mobility 2DEG with large external magnetic field at low temperature. Two-dimensional van der Waals materials, such as graphene and black phosphorus, are considered interesting material systems to study quantum transport, because it could unveil unique host material properties due to its easy accessibility of monolayer or few-layer thin films at 2D quantum limit. Here for the first time, we report direct observation of QHE in a novel low-dimensional material system: tellurene.High-quality 2D tellurene thin films were acquired from recently reported hydrothermal method with high hole mobility of nearly 3,000 cm2/Vs at low temperatures, which allows the observation of well-developed Shubnikov-de-Haas (SdH) oscillations and QHE. A four-fold degeneracy of Landau levels in SdH oscillations and QHE was revealed. Quantum oscillations were investigated under different gate biases, tilted magnetic fields and various temperatures, and the results manifest the inherent information of the electronic structure of Te. Anomalies in both temperature-dependent oscillation amplitudes and transport characteristics were observed which are ascribed to the interplay between Zeeman effect and spin-orbit coupling as depicted by the density functional theory (DFT) calculations

A Unified Health Information System Framework for Connecting Data, People, Devices, and Systems

The COVID-19 pandemic has heightened the necessity for pervasive data and system interoperability to manage healthcare information and knowledge. There is an urgent need to better understand the role of interoperability in improving the societal responses to the pandemic. This paper explores data and system interoperability, a very specific area that could contribute to fighting COVID-19. Specifically, the authors propose a unified health information system framework to connect data, systems, and devices to increase interoperability and manage healthcare information and knowledge. A blockchain-based solution is also provided as a recommendation for improving the data and system interoperability in healthcare