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Pearlite growth in steels is described by diffusion models, yet predicted rates are lower than experiments. The role of internal strain remains unclear due to limited direct experimental evidence. Here, in-situ neutron diffraction was used to investigate phase-specific lattice-strain evolution during the isothermal pearlitic transformation of Fe-0.8C steel at 973 and 953 K. Independently determined stress-free reference lattice parameters were adopted. At 973 K, austenite exhibited tensile phase strain, whereas ferrite and cementite showed compressive phase strains, consistent with the constrained expansion of pearlite within the surrounding austenite. Larger lattice strain magnitudes were observed at 953 K, in agreement with the greater volume expansion measured by dilatometry. The FWHM values of austenite and ferrite decreased slightly during transformation, indicating a reduction in the volume-averaged heterogeneous strain. These data provide direct evidence of strain partitioning during pearlite transformation, refining transformation models and microstructure simulations.
Departure from nucleate boiling (DNB) in subcooled flow boiling leads to an abrupt rise in the heat transfer surface temperature within a short time. In light water reactors, knowledge of DNB heat flux is essential to prevent the catastrophic failure of heating elements. However, accurately predicting DNB heat flux remains challenging due to the underlying physical complexities. Existing empirical correlations, mechanistic models, and AI-aided models in the open literature continue to exhibit certain limitations, such as disagreements on the dominant DNB mechanism or the inherent lack of transparency in black-box AI frameworks. In this study, an artificial neural network (ANN) is utilized to analyze the interrelationships between DNB heat flux and eight influential dimensionless parameters gathered from extensive literature resources. Subsequently, a minimal number of the most critical dimensionless quantities were extracted to develop a novel empirical correlation. The results demonstrate that the proposed model possesses superior characteristics, including high robustness, mathematical simplicity, broad applicability across diverse operating conditions, and independence from thermal-hydraulic parameters.
Plutonium trichloride (PuCl3) was synthesized by a solid-state reaction of plutonium nitride with cadmium chloride. Electrochemical studies of PuCl3–(NaCl–2CsCl) melt at 823–923 K revealed that Pu3+ ions are reduced to Pu metal by a single-step mechanism and that the apparent standard potentials of the Pu3+/Pu0 redox couple are given by E*(Pu3+/Pu0) = − 3.514 + 8.60 × 10−4 T vs. Cl2/Cl− (V). The activity coefficients of Pu3+ ions were determined using the previously reported Gibbs free energy of formation for PuCl3 in the supercooled liquid state.
We investigate the electromagnetic structure of heavy quarkonia and the B_c meson within the light-front quark model (LFQM) to better understand the internal spatial charge distributions and QCD dynamics of heavy mesons. The light-front wave functions (LFWFs) are obtained using a variational approach with a few set of harmonic oscillator basis functions, providing a flexible yet tractable description of the bound-state dynamics. Using these LFWFs, we compute the electromagnetic form factors and compare our results with available lattice QCD data and other model calculations. Our results are roughly consistent with previous model predictions, showing that the electromagnetic radii of the 2S and 3S states are approximately 1.5 times and 1.9 times larger than those of their corresponding 1S states, reflecting the expected growth of spatial size in radial excitations.
Cosmic radiation exposure in both traditional and modern architectural structures has been assessed using the particle and heavy ion transport code system (PHITS) Monte Carlo simulation, across various ethnic regions of Cameroon. The study was conducted considering traditional architectures associated with ethnic groups in the West (Bamileke), Center (Bafia), South (Fang-Beti), Littoral (Sawa), East (Baka), Northwest (Tikar), and Southwest (Bakweri). The traditional architectures in these regions are primarily constructed using locally available materials such as wood, bamboo, thatch (straw), and mud bricks. Building shielding factors for traditional and modern architectures ranges from 0.964 to 0.999 and from 0.859 to 0.892 with an average value of 0.990 ± 0.009 and 0.872 ± 0.010, respectively, during solar minimum activity. The total average contribution of muons (μ⁺ and μ−) in traditional architectures was found to account for 64
