杏吧性世界

The renewable energy landscape is rapidly transforming, with renewables now forming a significant part of modern power grids. In the U.S., renewable sources (wind and solar) have become the second-largest contributor to electricity generation, reflecting a global shift toward cleaner, more sustainable energy systems. However, this growing dependence introduces new technical challenges, as these sources connect to the grid through Inverter-Based Resources (IBRs), electronic-switch-based devices that behave very differently from traditional generators. Unlike conventional power plants, IBRs lack physical inertia, making the grid more sensitive to disturbances and rapid fluctuations.  Real-world events have shown that IBRs can cause oscillations, particularly in different grid configurations where system strength and stability margins are limited.

In addition, traditional protection systems, designed for the high fault currents of rotating machines, often struggle to detect and isolate faults accurately in IBR-dominated networks due to the lower and less predictable current characteristics of inverters. This research investigates these emerging stability challenges through detailed simulations, mathematical modeling, and hardware experiments to understand and mitigate instability mechanisms. The analysis is done for the grid-following and grid-forming IBR technologies. It proposes a novel coordination method that enables multiple inverters to share reactive power more effectively, improving both small-signal and large-disturbance stability. Furthermore, a digital twin platform is developed to model and analyze inverter鈥揼rid interactions in real time, enabling proactive monitoring and control. Together, these contributions strengthen the reliability, flexibility, and resilience of future renewable-powered electric grids.

Borrelia burgdorferi, the bacteria causing Lyme disease, is transmitted between the tick vector and mammalian host. To survive in such vastly different environments, B. burgdorferi alters its gene expression in response to environmental signals. Understanding how the bacterium regulates its gene expression is essential to identify therapeutic and/or vaccine targets. Previous studies identified a DNA binding protein, BadR, as a regulator of gene expression in B. burgdorferi. Additional studies indicated BadR is essential for mammalian infection and that BadR is highly expressed when B. burgdorferi resides in the tick vector. However, the requirement for BadR during tick phases of the lifecycle has remained unexplored. Therefore, we first used in vivo tick and mouse models to investigate the requirement for BadR during tick intermolt, tick-mammal transmission, and mammalian infection.

Our findings confirmed BadR is required for B. burgdorferi to survive transmission from ticks to mammals, in the mammalian host, and in tick midguts during molting. Furthermore, we identified genes regulated by BadR under conditions mimicking the mammalian host and unfed tick. These global analyses identified novel genes in the BadR regulon and provided evidence that BadR contributes to gene regulation at the DNA and protein level. Finally, we investigated the contributions of select BadR targets to the infectious cycle of B. burgdorferi. Namely, we investigated the gene bb0556, annotated as a hypothetical protein, using a mouse imaging model and found it is required for mammalian infectivity. Together, this work has further elucidated the role of BadR and BadR targets in B. burgdorferi survival and infectivity.