Magnetic reconnection is a fundamental process in plasmas in which magnetic flux is converted to kinetic and thermal energy. Key to understanding reconnection is measuring electromagnetic fields. Recent experiments have utilized high-repetition-rate laser-driven plasmas to study reconnection in 3D, but the electromagnetic measurements are relatively sparse spatially, making reconstructing reconnection dynamics challenging. Data assimilation techniques can leverage these datasets to reconstruct field evolution across the entire spatiotemporal domain. We present a new technique using weak-constraint 3-dimensional variational assimilation (weak 3D-var) to combine sparse measurements with numerical models for higher spatial resolution of fundamental plasma dynamics. We demonstrate the effectiveness of weak 3D-var in wave phenomena from simulated electromagnetic measurements and compare with other candidates for field reconstruction.

In an effort to meet the energy storage demands of our increasingly electrified energy economy, Li-metal batteries (LMBs) have emerged as a promising battery system. Compared to the industry-standard Li-ion batteries (LIBs) which employ a graphite anode, LMBs use an anode-free architecture that renders a tenfold increase in theoretical specific capacity (3860 mAh/g from 372 mAh/g). Li metal’s low electrochemical reduction potential (-3.04 vs SHE) also helps to achieve higher operating voltages and power output. However, due to Li metal’s inherent reactivity, significant drawbacks still hinder commercialization of LMB technology, from short-circuiting dendrite formation to poor cycling performance. One strategy to overcome these obstacles is to engineer a stable solid-electrolyte interphase (SEI) – the self-passivating layer that forms atop Li metal in contact with electrolyte. Here, we perform continuous and calendar-aged battery cycling protocols across Li||Cu half-cells to benchmark Li anode performance in the presence of chemically “aged” electrolyte from three different model electrolyte systems: 1M LiPF6 in EC:DEC and 4M and 1M LiFSI in DME. We further aim to correlate performance with evolution of ionic components over time using LC/MS and thereby providing insights to help inform electrolyte design and manufacturing strategies for a robust SEI and thus reliable LMBs.  

Quantum computing, at its most fundamental level, relies on the coherent control of a  two-level system. Among the leading platforms are semiconductor quantum dots, where  qubits are realized by manipulating the trapping potential of single charges. Before  precise qubit control can be achieved, however, it is essential to identify and  characterize the electronic states.  One of the least invasive readout methods employs microwave resonator systems.  These resonators detect shifts in resonant frequency caused by capacitive changes in  the quantum dot and transmit extremely weak microwave signals (on the order of  10 −13  W) to a chain of amplifiers. Maintaining a low noise floor in these amplifiers is  critical to ensure that the signal is not overwhelmed by noise. In this talk, I will present  my work on developing a cost-efficient, low-noise amplifier capable of operating at  cryogenic temperatures.  Using this readout system, we obtain charge stability diagrams, which map the electron  occupation of the dots as a function of gate voltages. These voltages control the  trapping potential, which in turn determines tunneling rates and electron exchange  between the dots. In the second part of my presentation, I will describe my contributions  to modeling interdot transition behavior using Python, and how this analysis aids in the  characterization of quantum dot devices. By achieving better control over the tunneling  barrier, we aim to operate the device in a strongly coupled regime, enabling efficient  charge–photon interactions.  

Orthogonal reactivity towards distinct monomers can be achieved using redox switchable catalysts, which toggle between the oxidized or reduced form within the ferrocene backbone through electron transfer. Using switchable catalysis, a variety of block copolymers have been synthesized yet precise sequence control necessitates further research. We propose an electrochemical approach that reversibly switches the catalyst redox state and provides precise monomer control. Ferrocene-based redox switchable catalysts allowed for testing of the polymerization rate and orthogonal reactivity of different monomers (lactones, epoxides, cyclic carbonates). In order to characterize the electrochemical stability and redox behavior of the catalysts, cyclic voltammetry was employed. This study aims to cement the foundation for using an electrochemical method to synthesize sequence-controlled polymers, allowing for satisfactory redox control and tunability of polymer properties. 

Orthopedic implants benefit from the ability to deform under load, which can enhance their long-term mechanical performance and address issues necessitating surgical revision. We propose a device that introduces compliance into an implant through a flexible load-bearing mechanism. In this work, we present the mechanism’s geometric design parameters and performance. We established two design spaces for a titanium (Ti64) implant, demonstrating implant behavior both in series and within cortical bone. FEA simulations indicate nonlinear behavior when assessing variations in stress and stiffness for both design paradigms. We anticipate these findings will form a scalable design framework for compliant prostheses to enhance patient outcomes.