Archives: Portfolios

This research aims to apply multiple turbulence generation methods to a plane within the computational domain, rather than at the inlet as is usual. The advantage of this is in its computational efficiency. The efficiency of Computational Fluid Dynamics (CFD) simulations is greatly affected by the mesh, or grid, on which they are solved. A finer mesh will yield more accurate results but take a significantly longer time to complete. By applying turbulence further in the domain than the inlet (i.e. closer to the airfoil or test body), the mesh can be coarser near the inlet and only be refined where the turbulence is applied. Otherwise, the fine mesh would have to cover the whole domain, as turbulence will quickly dissipate artificially without very small grid sizes. The other purpose of this research is to produce a turbulence generation method which combines existing methods in order to reduce the adaptation distance after the turbulence is injected. Turbulence generated in computational domains require some distance after their injection in order to stabilize and naturalize to the specific flow conditions. This can lengthen computational domains and further slow efficiency. Multiple methods have been shown to reduce this distance, and I plan to implement some of these in my work.

Characterizing plasma-wave interactions is critical to understanding particle energization mechanisms in space plasma environments and in applied technical fields. Currently, there is no conventional scattering theory for waves in plasma physics. Our research project is focused on the study of waves interacting with plasma ions trapped in a dipole magnetic field. Charged particles in a dipole field undergo a range of periodic and chaotic orbits, providing a general particle trajectory as a test bed for plasma wave scattering. Laser-induced fluorescence (LIF) techniques allow measurement of incident and reflected wave coefficients of ion acoustic waves launched toward the trapped plasma, allowing comparison to models being developed for describing the physics of these plasma wave interactions. Using LIF, we plan to describe approaching and trapped ion behavior as a function of velocity, as well as the incident and reflected wave interactions with the ions. Initial Langmuir Probe measurements have been made to describe the plasma conditions in and around the dipole magnet, and to measure the wave-induced variations in particle flux as a function of time and distance from the magnet.

Resupply missions for spacecraft suffer from limited cargo space, requiring prioritization of materials. Improvements to supply availability and variety could be made with the production of devices on demand where raw material is transported instead. This would allow for the freedom to produce a device independently, making the most out of limited cargo space. Electrohydrodynamic EHD inkjet printing is a printing technique that uses an electric field to jet the ink onto a substrate. The electric field has the effect of pulling the ink onto the working substrate, allowing the printer to function effectively in a low-gravity environment, as well as focusing the ink into a stream smaller than the printhead nozzle, allowing for micron-level resolution. This printing technique has different ink requirements than more traditional inkjet printing, and, being relatively new, there are no commercially available inks for use in EHD printing. Prior art examines conductive materials (silver, gold, copper, etc.) but not non-metallic materials, which provide broader functionality to electronics, giving the ability to produce dielectric and semiconductor devices. My current research involves the development of a reactive zinc oxide ink for the printing of transistors and memory devices. Motivation towards this approach, as opposed to a more conventional nanoparticle dispersion, was brought about by the potential of higher levels of printing resolution being unhampered by particle size and the ability to deposit ink within already fabricated nanoscale silicon substrates. Final device functionality is heavily dependent upon materials synthesis and processing. Electronic properties and device type, for example, may be selected through the level of crystallinity of the material or lack thereof (amorphous). The utilization of multiple materials to create a final device (a metallic ink to produce a conductive pattern and a ceramic ink to provide functionality) and long-term goals of utilization on the International Space Station necessitate the development of an ink to deposit a ceramic layer that can be processed at a low temperature.

My research project focuses on the integration of unmanned aerial vehicles (UAVs) into traditional air traffic systems operating in proximity to airports, which is a topic of ongoing investigation by various NASA research groups. This research falls within the broader domain known as Urban Air Mobility (UAM), which strives to create an efficient autonomous vehicle system for urban environments characterized by heavy air traffic. The primary goal of UAM is to ensure the safe and efficient operation of UAVs in complex urban airspace. Weare developing a cooperative planning and control framework that will enable the safe integration of UAVs into traditional air traffic systems. The bulk of this work lies in quantifying the rules of the road of aerial navigation and to then design an optimal control framework that provides the UAVs with optimal, efficient, and guaranteed-safe trajectories to allow the integration of UAVs into the complex, safety-critical environment that is the airspace. This cooperative planning and control framework will enable UAVs to navigate through the airspace, respond to dynamic changes in traffic patterns, and make autonomous decisions to avoid collisions with manned aircraft. This research has the potential to revolutionize the airspace, allowing UAVs to coexist seamlessly with conventional air traffic systems. With this work, we aim to enhance the safety and efficiency of urban airspace and contribute to the realization of Urban Air Mobility.

My research focuses on the development of safe and sustainable radiation-resist materials for space technology. Currently, NASA uses an organic material known as polyethylene as radiation shielding on-board the International Space Station. This work will expand on other organic materials which would be highly competitive radiation shielding materials in space. Aromatic-containing materials increase the structural stability compared to the already employed organic-based materials for radiation shielding. This work aims to engineer radiation resistant organic materials that can be used as coatings on space technology to prevent system malfunctions and degradation due to prolonged high ionizing radiation exposure by changing bonding networks within naphthalene-containing cocrystalline materials.
These cocrystalline materials have been reported to be tunable in their physical and chemical properties, providing us the capabilities to modify these materials for specific purposes such as increased structural stability and radiation resistance. Currently, I am comparing how changing the amount of aromaticity within naphthalene-based materials impacts the structural integrity of these materials when exposed to gamma radiation. Overall, these results will provide fundamental insights into rationally designing safe and sustainable radiation shielding materials for space technology coatings in the future.

My research project involves assisting Professor Matthew Nelson with engineering education through STEM engagement of K-12 students and teaching undergraduate students professional development skills such as time management, communication, decision-making, and adaptability. Working with the Make to Innovate high altitude balloon team, HABET, we are researching and carrying out new and innovative ways to get younger students involved with and excited about STEM through unique engineering experiences. This is done in hopes of engaging them to learn more about the fields included in STEM and to inspire the next generation of aeronautical innovators who will continue to transform the aviation industry, making it more sustainable and accessible. One of the ways this was achieved was by having kids under the age of thirteen participate in assisting with the launching of two balloons this past summer at the Iowa State Fair. As for the HABET team, they continue to develop their professional skillset by working with various clients ranging from physicists from the University of Iowa to the Food Sciences department here at Iowa State. I have aided in this development by coaching communication with clients and mentoring students in the decision-making process and adaptability between each client’s specific needs. Through high-altitude ballooning, this research falls unconventionally under the Aeronautic Research Directive due to its use of specific use of aeronautics in assisting with education research.

The objective of my Ph.D. research is to test the hypothesis that large-scale discrete multidisciplinary design optimization (MDO) can maximize complex, next-generation engineering systems’ performance automatically, which has not been possible with existing numerical methods. Specifically, I am looking at a new optimization framework considering low-thrust trajectory optimization with discrete fly-by options to enable more frequent and affordable missions, which aligns well with NASA’s mission to explore and extend our knowledge about the universe. MDO is a promising approach to tackle the above optimization because it can automatically use multiphysics simulations to find the best possible design, significantly reducing the design time. Existing gradient-based MDO algorithms can efficiently handle many design variables but cannot deal with discrete variables. In my PhD research, I will create a new large-scale discrete MDO framework (LSDMDO) to tackle the above challenge. LSDMDO is a novel class of optimization algorithms that efficiently synergize the gradient-based and evolutionary optimization methods to enable large-scale MDO problems with discrete variables. The LSDMDO algorithm will be rigorously derived, characterized, and evaluated in my PhD research.

On Earth today, plants comprise the vast majority of fixed carbon in biomass and plant growth may be limited by bioavailable N. Studying the evolution of the terrestrial C cycle depends on understanding how plants fixed C and the availability of N in their environments. The relationship between C and N may reflect a combination of atmospheric isotopic signatures of CO2 and soil N availability. By cultivating plants in growth chambers with various CO2 and N2 fluctuating conditions, we can track plant adaptability and compare isotope plant tissue concentrations through time. I will periodically sample plant material throughout the experiment to track how plant growth can vary and how different concentrations of CO2 are stored within plant tissue. Also, I will track nitrogen and nutrient availability in the soil to understand the effect that strenuous conditions can have on the microbial communities that contribute to plant nutrient uptake. This research will allow for a deeper understanding of how plant tissues adapt to environmental changes in trying conditions and can be directly applied in growth chambers experiments done in space. It will open doors to studying plant adaptability and the minimal conditions needed for efficient plant growth on Earth and in space.