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Marine macroalgae in the Gulf of Mexico is an important potential source for biofuel. However, identifying locations with the correct biogeochemical and hydrodynamic conditions for cultivation on a large enough scale to meet the needs of the U.S. private energy sector is impossible from purely observational studies. Large-scale, HPC modeling of earth systems processes enables researchers to study complex physical relationships with high fidelity. Here, we present novel visualization techniques showing the results of a global run of the E3SM’s MPAS-Ocean model data with biogeochemistry extensions to improve ongoing research in macroalgae cultivation. 

Stars that interact with supermassive black holes (SMBHs) can be either completely or partially destroyed by tides. In a partial tidal disruption event (TDE), the high-density core of the star remains intact, and the low-density outer envelope of the star is stripped and feeds a luminous accretion episode. The TDE AT 2018fyk, with an inferred black hole mass of 10^7.7±0.4M_⊙, experienced an extreme dimming event at X-ray (factor of >6000) and UV (factor of ∼15) wavelengths ∼500–600 days after discovery. Here we report on the reemergence of these emission components roughly 1200 days after discovery. We find that the source properties are similar to those of the predimming accretion state, suggesting that the accretion flow was rejuvenated to a similar state. We propose that a repeated partial TDE, where the partially disrupted star is on an ∼1200 day orbit about the SMBH and periodically stripped of mass during each pericenter passage, powers its unique light curve. This scenario provides a plausible explanation for AT 2018fyk’s overall properties, including the rapid dimming event and the rebrightening at late times. We also provide testable predictions for the behavior of the accretion flow in the future; if the second encounter was also a partial disruption, then we predict another strong dimming event around day 1800 (2023 August) and a subsequent rebrightening around day 2400 (2025 March). This source provides strong evidence of the partial disruption of a star by an SMBH.

 

Chinese Dynamic penetration test (DPT) is an in-situ testing with the advantages of simple apparatus, economical test, and continuous data acquisition, especially for measuring bearing capacity, relative density and classification of gravelly soils. The typical gravelly soils sites are selected from the Chengdu Plain in China and the river bed of Echo dam downstream in the U.S., and China-US dynamic penetration testing and hammer energy measurements are conducted. The results show that: (1) The average of energy transfer ratios is 90% and the standard deviation is 7.7%, derived from 1321 energy time-history records, tested at 3 gravelly soils sites in the Chengdu Plain. The deviation is greatly affected by operation procedure. (2) The DPT test depth, using US drill rig assembling with Chinese DPT cone, can reach as much as 20 meters for assessing soil properties. (3) The average of energy transfer ratios is around 74% and the standard deviation is 8.7%, derived from 1438 energy time-history records, tested at 2 gravelly soils sites on the river bed of Echo dam downstream. The deviation is greatly affected by friction of drill rod and rope. (4) The DPT blows should be corrected according to different hammer energies. The proposed evaluation method for gravelly soils liquefaction, developed from the DPT database of gravelly soils liquefied during 2008 Wenchuan Earthquake, can be applicable for worldwide use. 

The superτ-charm facility (STCF) is an electron–positron collider proposed by the Chinese particle physics community. It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5 × 10³⁵cm⁻²·s⁻¹or higher. The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory — the BEPCII, providing a unique platform for exploring the asymmetry of matter-antimatter (charge-parity violation), in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions, as well as searching for exotic hadrons and physics beyond the Standard Model. The STCF project in China is under development with an extensive R&D program. This document presents the physics opportunities at the STCF, describes conceptual designs of the STCF detector system, and discusses future plans for detector R&D and physics case studies.

 

We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers.

 

Abstract KAGRA, the underground and cryogenic gravitational-wave detector, was operated for its solo observation from February 25 to March 10, 2020, and its first joint observation with the GEO 600 detector from April 7 to April 21, 2020 (O3GK). This study presents an overview of the input optics systems of the KAGRA detector, which consist of various optical systems, such as a laser source, its intensity and frequency stabilization systems, modulators, a Faraday isolator, mode-matching telescopes, and a high-power beam dump. These optics were successfully delivered to the KAGRA interferometer and operated stably during the observations. The laser frequency noise was observed to limit the detector sensitivity above a few kilohertz, whereas the laser intensity did not significantly limit the detector sensitivity.