Computational design, fabrication, and characterization of microarchitectured solid oxide fuel cells with improved energy efficiency

Electrodes in a solid oxide fuel cell (SOFC) must possess both adequate porosity and electronic conductivity to perform their functions in the cell. They must be porous to permit rapid mass transport of reactant and product gases and sufficiently conductive to permit efficient electron transfer. However, it is nearly impossible to simultaneously control porosity and conductivity using conventional design and fabrication techniques. In this dissertation, computational design and performance optimization of microarchitectured SOFCs is first investigated in order to achieve higher power density and thus higher efficiency than currently attainable in state-of-the-art SOFCs. This involves a coupled multiphysics simulation of mass transport, electrochemical charge transfer reaction, and current balance as a function of SOFC microarchitecture. Next, the fabrication of microarchitectured SOFCs consistent with the computational designs is addressed based on anode-supported SOFC button cells using the laser ablation technique. Finally, the performance of a fabricated SOFC unit cell is characterized and compared against the performance predicted by the computational model. The results show that the performance of microarchitectured SOFCs was improved against the baseline structure and measured experimental data were well matched to simulation results.Ph.D.Committee Chair: Das, Suman; Committee Member: Halloran, John; Committee Member: Liu, Meilin; Committee Member: Sitaraman, Suresh; Committee Member: Wepfer, Willia

A Study of Prizes and Competitions

Conducted over a ten-month span between 2020 and 2021, this study describes the world of prizes and competitions in philanthropy, as well as similar efforts in other industries, including national governments, international agencies, and the private sector.The study identified more than 550 prizes and competitions with an aggregate purse prize of more than $1 billion, analyzed more than 160 prizes and competitions from 2020, and interviewed more than 50 donors, senior executives, prize administrators, and researchers and consultants from multiple industries to achieve the following:Describe the current landscape of prizes and competitions including the actors who fund and administer them;Identify common themes or practices across industries;Outline possible motivations for, benefits of, and reservations against, the use of prizes and competitions.Because of the breadth of variations in prize design, the study did not define, prescribe, or list a set of best practices. Instead, it sought to outline broad themes based on the best available dat

A STUDY ON AN AR-BASED CIRCUIT PRACTICE

Recently, the number of AR-based practice cases has been increasing. In this paper, the effect of AR-based circuit practice was examined through an experiment with 60 subjects (control group: 30, experimental group: 30). The report score, completion time, question count, and USE questionnaire were used in the analysis. As a result of the experiment, the report score was significantly increased by 15.48% in the experimental group (△report: +18 points) than in the control group (△report: +7 points). Question count decreased twice as much in the experimental group (△question: -18 times) as in the control group (△question: -9 times). The completion time of the experimental group (△time: -16 min) was reduced by approximately 4 min more than that of the control group (△time: -12 min), however, the difference was not statistically significant. The USE questionnaire received evaluations of 6.0 or higher (on a 7-point scale) in all categories (usefulness, ease of use, ease of learning, satisfaction). Therefore, From the experimental results, the proposed AR-based circuit practice is confirmed to be more effective than traditional circuit practice