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The upgraded summing NaI(Tl) (SuN++) absorption spectrometer
Full text linkSimulations of astrophysical processes require a plethora of nuclear physics input. In particular, models of neutron-capture nucleosynthesis like the s, i, and r processes require β-decay information and experimentally constrained neutron-capture reaction rates. Past experiments with the 4π Summing NaI(Tl) (SuN) total absorption spectrometer have provided these physics quantities. Here, we outline an upgrade of SuN to SuN++, where 20 new segments (12 NaI(Tl) and 8 CeBr3) have been integrated into the pre-existing SuN total absorption spectrometer to provide increased energy and time resolution in β-decay experiments. The details of the newly upgraded SuN++ total absorption spectrometer are discussed with results from the commissioning experiment at the Facility for Rare Isotope Beams (FRIB) utilizing a 70Cu beam
Quantifying the effect of temperature on belite hydration kinetics through quasi in situ XRD
Full text linkBelite-rich cement is a promising low-carbon material, yet the limited hydraulic reactivity of its primary component, dicalcium silicate ( β -Ca2SiO4), still poses a challenge. This study introduces a new approach to examining the reaction kinetics and acceleration strategies for low-reactivity materials like β -Ca2SiO4 using quasi in situ X-ray diffraction (XRD). By simultaneously analyzing pre-cured and fresh samples, the method reduces measurement time at the expense of lowering temporal resolution. Applying this technique to hydrating β -Ca2SiO4 pastes from 21 to 80 °C provides insight into the underlying temperature-dependent dissolution process and its apparent activation energy (AAE). The estimated AAE of 49 ± 3 kJ/mol aligns with existing data and supports the view that the rate-limiting step of belite hydration may change based on the physical properties of the material. By offering phase-specific and time-resolved data, this method serves as a useful tool in devising science-informed strategies to accelerate hydration of belite-rich cements
Coupled THM modeling of bentonite heating and hydration in tank tests with a new temperature-dependent water retention model
No full textThis study presents a coupled thermo-hydro-mechanical (THM) model for simulating the heating and hydration behavior of bentonite, a buffer material in deep geological repositories (DGRs). The model incorporates a new temperature-dependent soil water retention curve which captures the thermal-induced shift in water retention behavior. It also distinguishes between liquid and gas permeability, modeling intrinsic gas permeability as a function of accessible porosity to improve vapor transport and desaturation predictions. The model was validated against two large-scale tank tests, demonstrating good agreement with measured temperature, relative humidity, and water inflow data. It revealed a complex porosity evolution driven by thermal expansion, vapor movement, vapor condensation, and hydration-induced swelling during heating and hydration processes. The simulation results also suggest that the permeability of the hydration layer plays a critical role in controlling water intake. Clogging of this layer can significantly reduce the volume of water inflow during the hydration phase. While the model effectively captures key THM behavior, further development of the mechanical constitutive law is required to account for possible thermo-elasto-plastic volume changes and microstructural effects. Overall, the model provides a robust tool for evaluating the evolution of bentonite-based barrier material in DGRs
Latent Diffeomorphic Dynamic Mode Decomposition
No full textWe present Latent Diffeomorphic Dynamic Mode Decomposition (LDDMD), a new data reduction approach for the analysis of non-linear systems that combines the interpretability of Dynamic Mode Decomposition (DMD) with the predictive power of Recurrent Neural Networks (RNNs). Notably, LDDMD maintains simplicity, which enhances interpretability, while effectively modeling and learning complex non-linear systems with memory, enabling accurate predictions. This is exemplified by its successful application in streamflow prediction
Structural Behavior and Design of Recycled LDPE-FRP Hybrid Beams for Bridge Collision Protection
Full text linkBoolean Schubert structure coefficients
Full text linkThe Schubert problem asks for combinatorial models to compute structure constants of the cohomology ring with respect to Schubert classes and has been an important open problem in algebraic geometry and combinatorics that guided fruitful research for decades. In this paper, we provide an explicit formula for the (equivariant) Schubert structure constants c u v w across all Lie types when the elements u , v , w are boolean. In particular, in type A, all Schubert structure constants on boolean elements are either 0 or 1
Magnetic Field Mapping of a 2.5 T Fixed-Field HTS Gantry Magnet for Proton Therapy
Full text linkWe present results from testing a high-temperature superconducting (HTS) magnet prototype for proton therapy. This magnet is specifically designed for a novel rotating gantry capable of delivering the entire proton beam energy range (70–225 MeV) while maintaining a fixed magnetic field in the superconducting magnets. The gantry layout simplifies the magnet design, enabling the use of straight, flat racetrack Bi-2223 (DI-BSCCO) coil technology and operation at higher temperatures (10–15 K). The magnet has a non-linear field distribution for bending and focusing the proton beams. To validate this feature, we developed a system for measuring the magnetic field distribution in the magnet aperture. We present the design of this hall probe array and experimental results from two different magnet tests at 4.2 K in a liquid helium bath. These results are compared with the simulated field distribution and discussed in the context of the required field quality for the application
Inducible flippase-mediated metabolic engineering of Rhodosporidium toruloides for enhanced 3-hydroxypropionic acid production from corn stover hydrolysate
Full text linkRhodosporidium toruloides has gained increasing interests as a promising non-model host organism to produce a wide range of bioproducts from lignocellulosic biomass. Increasing the bioproduct titers, rates, and yields remains a challenge, largely due to a lack of robust and well-characterized genetic tools in this host. Here we developed an inducible flippase (FLP) and flippase recognition target (FRT) system that enables genetic manipulations without the need for additional selection markers. Synthetic inducible promoters were established, enabling regulation of FLP expression and efficient antibiotic marker removal. Leveraging this system, we engineered a strain to optimize 3-hydroxypropionic acid (3HP) production. Over four rounds of iterative genomic editing to resolve pathway bottlenecks, we achieved a 3HP titer of 69.4 g/L in fed-batch fermentation - the highest level reported in yeast from lignocellulosic hydrolysates. The engineered high 3HP producing strain offers a robust platform for sustainable bio-based chemical production from lignocellulosic feedstocks
Impacts to birds from marine oil spills in California, 1995–2019
Full text linkWe compiled data on marine and coastal petroleum oil spills in California during 1995-2019 that affected ≥10 birds (n = 30). These spills resulted in the collection of 12,842 birds (5241 collected alive, 7601 collected dead). Frequency of spills decreased over the study period, and varied intra-annually, with more spills and more birds collected during fall and winter months. The greatest number of spills affecting birds were in southern California (19/30), although far more birds were collected from spills in northern California (11,570/12,842). Most spills in southern California were related to oil production or pipeline transport, whereas most spills in northern California (and most impacted wildlife) were related to non-tank vessel spills. The most abundant bird species affected were Common Murre (Uria aalge), Western or Clark's Grebe (Aechmophorus occidentalis/clarkii), and Surf Scoter (Melanitta perspicillata). Species-specific injury rates were roughly in proportion to species' abundance in the spill area and the amount of time they spend on the surface of the water. Some species were collected more often live than dead and these species also tended to have higher release rates. This information on geographic, temporal, and species-specific risk to birds from oil spills can be used to inform effective prevention and response measures for oil spills in California and elsewhere