41530 research outputs found
Sort by
High-Frequency Current and Voltage Sensing Buck Converter Compatible with Model Predictive Control
Get PDFThis paper presents the design and implementation of a high-frequency buck converter operating at 1 MHz, integrated with voltage and current sensing capabilities for enhanced output regulation. The primary objective is to minimize transient dips in output voltage commonly observed during load disturbances or switching events. The converter design is intended to be compatible with a Digitally Assisted Analog Computing Circuit (DAACC) for real-time model predictive control (MPC), which leverages fast analog elements with programmable digital components to solve a penalty-based reformulation of the quadratic optimization problem underlying conventional MPC
Vertical and Latitudinal Variability of Marine Heatwaves in the California Current
Get PDFMarine heatwaves (MHWs) are increasing in frequency and intensity globally, with grave effects on marine ecosystems and their dependent industries. There are significant gaps in knowledge of the subsurface behavior and geographic distribution of MHWs, especially in eastern boundary upwelling systems like the California Current. Here, two decades of full water-column temperature observations from a shallow autonomous profiler in San Luis Obispo Bay (~10m) revealed that while MHWs have similar average durations and intensities across all depths, one-third of bottom MHWs occur without a concurrent surface signal. MHWs across the water column initiated during anomalously weak upwelling or downwelling conditions and displayed stratification-driven seasonal shifts in vertical structure. Next, two decades of NOAA NDBC surface buoy temperature measurements distributed along the US West Coast shelf revealed the latitudinal variation of MHWs in the California Current. MHWs displayed various spatial extents, from coast- wide events to site-specific occurrences, and various drivers, from basin-scale climate modes (e.g., Pacific Decadal Oscillation, El Niño Southern Oscillation) to site-specific conditions. Upwelling contributed to MHW occurrence across the coast, with both initiation and termination of MHWs linked to weak and strong upwelling anomalies, respectively. Central and Northern California displayed the strongest link between upwelling and MHWs, while Oregon/Washington and Southern California displayed higher regional co-occurrences. Across 7 MHW metrics and 22 sites, there was only one statistically significant positive long-term trend (i.e., increase in MHWs), suggesting that the US West Coast could serve as a thermal refuge for marine organisms. These findings improve the understanding of MHW variability in upwelling systems and highlight the need for sustained long-term observations and depth-resolved, geographically distributed observational infrastructure to support forecasting, ecosystem resilience planning, and sustainable offshore infrastructure development in a changing and warming ocean
The Degrees of the Irreducible Representations of the Symmetric Group with Respect to Primes
Get PDFIn this thesis, we explore the relationship between the degrees of irreducible matrix representations of the symmetric group and prime numbers. We start by building up the required background necessary to construct our results. We dive into topics of discrete mathematics including matrix representations, characters of representations, integer partitions, conjugacy classes, class functions, and tableaux. Some other key ingredients in our work include using character tables to classify the irreducible rep- resentations of the symmetric group and the hook-length formula to easily compute the degrees of these representations. Once we have laid the groundwork for our in- vestigation, we begin exploring the relationship between degrees of representations and primes. The bulk of the work in this thesis hinges upon proving the claim that the total number of irreducible representations of the symmetric group of size n with degrees not divisible by a prime p is itself divisible by the same prime p. To do so, we utilize additional topics including abaci, cores and quotients of integer partitions, and facts regarding the factorization of prime numbers
Fault Box Modeling of Dip Slip Faults: A Framework for Fault Box Design and Future Studies
Get PDFThe behavior of soils during surface fault rupture is a serious concern in the planning and design of infrastructure that may be located within or near a fault zone. Challenges associated with developing mitigation measures for surface fault rupture include the uncertainty of fault rupture and the variability of fault behavior. Current analytical procedures define surface fault rupture according to the type of fault movement (strike slip, normal or reverse), the amount of displacement on the fault, and the mechanics of the material overlying the fault. The purpose of this thesis is to reconfirm analytical solutions and gain a better understanding of the mechanics of dip slip surface fault rupture. Specifically, this study focuses on analyzing the influence of soil density/stiffness and fault angle on rupture propagation and distributed surface displacements. While direct experimental results are not obtained, a constructed fault box and planned trials inform a framework for predicting the outcomes of these trials using existing literature. These prior studies provide a basis for forecasting the surface deformation patterns and propagation behavior that the planned trials would have revealed, offering valuable insights into fault rupture mechanics. The fault box, a 2-meter-long by 0.5-meter-wide fault box filled with 0.45 meters of Monterey #2/16 sand, was designed to examine the factors that influence the rupture propagation of alluvial soils overlying dip slip faults. The faulting apparatus consists of a scissor jack mechanism that replicates basal displacement by moving one half of the box relative to the stationary half at interchangeable fault angles. Planned trials involved using Monterey #2/16 sand prepared configurations of dense, loose, and layered loose-over-dense material to represent different geological conditions. In these planned experiments, ruptures would be driven until a clear shear band developed in the overlying sand and reached the surface. By synthesizing findings from prior studies, this research predicts that dense sands create concentrated shear bands with larger surface displacements and distinct surface ruptures, while loose sands result in more diffuse deformations over broader shear bands with less defined surface expressions. Additionally, shallow fault angles result in broader deformation zones, as the lower angle directs stress over a wider area. In layered soil configurations, density contrasts further influence deformation patterns, with transitions between layers influencing the extent and localization of surface displacements. These findings demonstrate that fault orientation and soil density control the nature of surface fault rupture
Still Accounting for my Teacher’s Body: The Objective Body/Body as Objective in the Classroom/ClassZoom
Get PDFThis critical commentary reflects on Cooks’ 2007 article, “Accounting for my Teacher’s Body: What can I teach/What can we learn?” by reconsidering power and body relations in light of the concept and pedagogy of body neutrality in the classroom in the 2023 COVID-19 era. The digital and physical classroom are spaces where the (embodied) body is never neutral. By extension, the body is never neutral anywhere regardless of the mindful body neutrality practices suggested by Pellizzer and Wade (2023). In this commentary, we first discuss how the teacher in physical and digital space communicates ideals of competence in performance of gender, sexuality, race, class, and ability in knowledge production. Then, we theorize and analyze how relational performances of teaching and learning are constrained and made possible through our bodies and/in technology. We wonder how our bodies become in/ authentic producers of knowledge and discuss a few ways in which we might challenge institutionalized forms of sexism and racism. We reflexively analyze how our whiteness, gender, class, and ability intersect to provide moments of learning for ourselves and our pedagogy as well as for our students
