More Like this

1. Nuclear structure and direct reaction studies in particle-γ coincidence experiments at the FSU John D. Fox superconducting linear accelerator laboratory

   https://doi.org/10.3389/fphy.2024.1511394  

   Spieker, Mark-Christoph; Almaraz-Calderon, Sergio (December 2024, Frontiers in Physics)

   Kay, Benjamin (Ed.)

   Since its foundation in the 1960s, the John D. Fox Superconducting Linear Accelerator Laboratory at Florida State University (FSU) pursued research at the forefront of nuclear science. In this contribution, we present recent highlights from nuclear structure and reaction studies conducted at the John D. Fox Superconducting Linear Accelerator Laboratory, also featuring the general experimental capabilities at the laboratory for particle- $\gamma$coincidence experiments. Specifically, we focus on light-ion induced reactions measured with the Super-Enge Split-Pole Spectrograph (SE-SPS) and the CATRiNA neutron detectors, respectively. Some results obtained with the CeBrA demonstrator for particle- $\gamma$coincidence experiments at the SE-SPS are presented. A highlight from the first experimental campaigns with the combined CLARION2-TRINITY setup, showing that weak reaction channels can be selected, is discussed as well. 

   more » « less
2. ADARE-HD: Adaptive-Resolution Framework for Efficient Object Detection and Tracking via HD-Computing

   Mejri, M; Amarnath, C; Chatterjee, A (August 2024, IEEE)

   Efficient and low-energy camera signal processing is critical for battery-supported sensing and surveillance applications. In this research, we develop a video object detection and tracking framework which adaptively down-samples frame pixels to minimize computation and memory costs, and thereby the energy consumed, while maintaining a high level of accuracy. Instead of always operating with the highest sensor pixel resolution (compute-intensive), video frame (pixel) content is down-sampled spatially, to adapt to changing camera environments (size of object tracked, peak-signal-tonoise- ratio (i.e, PSNR) of video frames). Object detection and tracking is supported by a novel video resolution-aware adaptive hyperdimensional computing framework. This leverages a low memory overhead non-linear hypervector encoding scheme specifically tailored for handling multiple degrees of resolution. Previous classification decisions of a moving object based on its tracking label are used to improve tracking robustness. Energy savings of up to 1.6 orders of magnitude and up to an order of magnitude compute speedup is obtained on a range of experiments performed on benchmark systems. 

   more » « less
3. Load-Modulating Loop Combiner for Linear Power Amplification

   https://doi.org/10.1109/LMWC.2022.3211162  

   Sear, William; Barton, Taylor W. (February 2023, IEEE Microwave and Wireless Components Letters)

   This work presents a novel power amplifier (PA) architecture employing a feedforward-like loop structure for the linearization of a load-modulated PA. The load-modulating loop combiner (LMLC) is related to a feedforward amplifier, but with the interaction between the main and auxiliary amplifiers to generate both distortion cancellation and load modulation. A brief overview of the underlying theory is presented, followed by a hardware demonstrator operating at 3.5 GHz with 42-dBm peak output power and 55% peak drain efficiency in CW. When excited by a 100-MHz LTE signal, it maintains a 3-ppt EVM improvement and a 2–5-ppt average drain efficiency improvement compared to its standalone main amplifier. 

   more » « less
4. Trinity IV: predictions for supermassive black holes at z ≳ 6

   https://doi.org/10.1093/mnras/stae1447  

   Zhang, Haowen; Behroozi, Peter; Volonteri, Marta; Silk, Joseph; Fan, Xiaohui; Aird, James; Yang, Jinyi; Wang, Feige; Tee, Wei Leong; Hopkins, Philip F (June 2024, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We present predictions for the high-redshift halo–galaxy–supermassive black hole (SMBH) connection from the Trinity model. Matching a comprehensive compilation of galaxy (0 ≤ z ≤ 13) and SMBH data sets (0 ≤ z ≤ 6.5), Trinity finds: (1) The number of SMBHs with M• > 109 M⊙ in the observable Universe increases by five orders of magnitude from z ∼ 10 to z ∼ 2, and by another factor of ∼3 from z ∼ 2 to z = 0; (2) The M• > 109 and 1010 M⊙ SMBHs at z ∼ 6 live in haloes with ∼(2 − 3) and (3 − 5) × 1012 M⊙; (3) the newly discovered JWST AGN candidates at 7 ≲ z ≲ 11 are overmassive compared to the intrinsic SMBH mass–galaxy mass relation from Trinity, but they are still broadly consistent with Trinity predictions for flux limited AGN samples with Lauer bias. This bias favours the detection for overmassive SMBHs due to higher luminosities at a fixed Eddington ratio. However UHZ1’s M•/M* ratio is still some 1 dex higher than Trinity AGNs, indicating a discrepancy; (4) Trinity underpredicts the number densities of GN-z11 and CEERS_1019 analogues. But given the strong constraints from existing data in Trinity, the extra constraint from GN-z11 and CEERS_1019 does not significantly change trinity model results. (5) z = 6–10 quasar luminosity functions will reduce uncertainties in the trinity prediction of the z = 6–10 SMBH mass–galaxy mass relation by up to ∼0.5 dex. These luminosity functions will be available with future telescopes, such as Roman and Euclid. 

   more » « less
5. Bidirectional River‐Floodplain Connectivity During Combined Pluvial‐Fluvial Events

   https://doi.org/10.1029/2021WR030492  

   Tull, Nelson; Passalacqua, Paola; Hassenruck‐Gudipati, Hima J; Rahman, Shazzadur; Wright, Kyle; Hariharan, Jayaram; Mohrig, David (March 2022, Water Resources Research)

   Abstract Hydrologic connectivity controls the lateral exchange of water, solids, and solutes between rivers and floodplains, and is critical to ecosystem function, water treatment, flood attenuation, and geomorphic processes. This connectivity has been well‐studied, typically through the lens of fluvial flooding. In regions prone to heavy rainfall, the timing and magnitude of lateral exchange may be altered by pluvial flooding on the floodplain. We collected measurements of flow depth and velocity in the Trinity River floodplain in coastal Texas (USA) during Tropical Storm Imelda (2019), which produced up to 75 cm of rainfall locally. We developed a two‐dimensional hydrodynamic model at high resolution for a section of the Trinity River floodplain inspired by the compound flooding of Imelda. We then employed Lagrangian particle routing to quantify how residence times and particle velocities changed as flooding shifted from rainfall‐driven to river‐driven. Results show that heavy rainfall initiated lateral exchange before river discharge reached flood levels. The presence of rainwater also reduced floodplain storage, causing river water to be confined to a narrow corridor on the floodplain, while rainwater residence times were increased from the effect of high river flow. Finally, we analyzed the role of floodplain channels in facilitating surface‐water connectivity by varying model resolution in the floodplain. While the resolution of floodplain channels was important locally, it did not affect as much the overall floodplain behavior. This study demonstrates the complexity of floodplain hydrodynamics under conditions of heavy rainfall, with implications for sediment deposition and nutrient removal during floods. 

   more » « less