General boundary conditions are implemented within a fast Fourier transform framework for linear and non-linear mechanical problems using small or finite transformation formulations. In the context of parallel computing (distributed memory), we present a framework that enables the combination of periodic and non-periodic (Dirichlet or Neumann) boundary conditions. Taking advantage of the link between non-periodic boundary conditions and the symmetries of the relevant components of the fluctuation displacement and stress fields, discrete trigonometric transforms are employed to adapt the classical Moulinec-Suquet fast Fourier transform approach. The present study employs an original displacement-based fixed-point algorithm in combination with a convergence acceleration method in order to solve boundary value problems. Finite difference approaches are used to build the discrete Green operators associated with a pre-conditioner (reference material), whose choice depends on the loading type and the small or finite transformation frameworks. The newly developed double tetrahedron scheme is employed to investigate non-periodic problems. Outcomes are compared to those of the classical hexahedral scheme. The robustness and computational efficiency of the presented parallel solver is demonstrated through numerical experiments of non-trivial loading scenarios (tension, bending, normal-mixed loading, torsion-bending), complex and densely discretized microstructures and diverse behavior laws (elasticity, isotropic plasticity, crystal plasticity), within small and finite transformation frameworks.
This study reports the synthesis of a Ti@TiO2/Ni nanocomposite containing 20 wt% Ni via sonohydrothermal treatment combined with ultrasonic reduction of Ni2+ using hydrazine. The composite exhibited notable photothermal activity toward hydrogen production in glycerol solution, achieving a rate of 4.41 mmol h- 1 g- 1 at 94 degrees C, which is 5.5 times higher than bare TiO2 with an activation energy of 22 +/- 1.5 kJ mol- 1. Interestingly, methane (CH4) formation was observed exclusively in the Ni-containing composite, attributed to a Ni-catalyzed methanation pathway. Photoelectrochemical measurements revealed that Ni incorporation does not enhance the photocurrent response, suggesting that the improved performance arises primarily from surface catalytic effects and thermally-assisted reaction pathways rather than enhanced charge separation. These findings demonstrate that Ni modifies the reaction pathway of Ti@TiO2, enabling dual H2 and CH4 production.
The use of advanced oxidation processes (AOPs) for micropollutant removal in wastewater is challenging, given the scavenging effects of dissolved organic matter (DOM). Chlorine photolysis (UV/Cl) offers unique advantages over conventional AOPs, with wavelength- and pH-dependent generation of reactive species, while being largely compatible with existing disinfection dosing infrastructure. Here, the UV/Cl treatment of carbamazepine (CBZ) was optimized as a test case by varying UV wavelength and solution pH in the presence of humic acid and various types of wastewater DOM isolates (colloidal, hydrophobic, and transphilic). CBZ degradation rates, competitive quenching experiments, and electron paramagnetic resonance spectroscopy revealed important wavelength- and pH-dependent trade-offs in the dominant oxidants. At pH 3, CBZ degradation was hindered by DOM due to scavenging of nonselective radicals. At pH 8, ozone formation minimized DOM interference and improved CBZ removal. Shifting to longer wavelengths caused changes parallel to raising the pH. Three-dimensional excitation-emission matrix fluorescence analysis revealed preferential reactivity with fulvic- and humic-like fluorophores during treatment. Microtoxicity bioassays indicated a slight increase in acute toxicity after UV/Cl exposure, and LC-MS identified hydroxylated, epoxidized, and chlorinated transformation products. Results highlight the potential for strategic optimization of UV/Cl to mitigate DOM interference in water treatment.
Most organoids are cultured in Matrigel, a complex and poorly defined matrix that limits our mechanistic understanding. Synthetic hydrogels offer a versatile alternative, providing precise control over mechanical and biochemical cues. Using two topologically different types of hydrogel precursors, branched poly(ethylene glycol) (PEG) and PEG bisdendrons, we have obtained a library of hydrogels via thiol-ene cross-linking with branched PEG-thiol. Their chemical conversion was monitored by Raman spectroscopy, while swelling and mechanical properties, including elastic, viscoelastic, and relaxation parameters, were systematically evaluated. Bisdendron hydrogels dissipate stress through abundant weak interactions, conferring adaptive viscoelastic behavior, an underexplored feature in a 3D culture. To link macromolecular dynamics with bulk properties, polymer chain mobility and internal architecture were probed using MAS solid-state NMR and freeze-fracture cryo-SEM. To introduce bioactivity, RGD peptides were used and immobilized via thiol-ene chemistry, forming spatially organized clusters within the hydrogels. This strategy enables the design of customizable matrices with tunable mechanics, adjustable porosity, and controlled bioactive presentation, closely mimicking native microenvironments. Our platform can provide a chemically defined and versatile toolbox for organoid culturing.
This study employs a novel integration of Computer Vision (CV) and Deep Learning (DL) algorithms (CNN/RNNLSTM algorithm) to investigate the acidity and photocatalytic performance of a green nanocatalyst: copper oxide nanoparticles supported on sodalite nanozeolite (nSOD@CuO-NPs). The nanocatalyst, synthesized using Camelia sinensis (green tea) extract, was characterized, revealing the sodalite, tenorite, and cuprite phases and a good compromise between surface area and stability. The NH3-TPD analysis indicated a presence of weak-to-moderate acidity of the nanocatalysts and a significant reduction in the density of acid sites upon CuO-NPs loading, decreasing from Ns = 135 & micro;mol NH3 g-1 catalyst (nSOD) to Ns = 58 & micro;mol NH3 g-1 catalyst (nSOD@CuO-NPs), probably due to occupation/blockage of nanozeolite active sites by the nanoparticles. This modification suggests a plausible transition from Br & Oslash;nsted-dominant to Lewis-dominant acidity, potentially enhancing oxidation reactions. Exploratory Data Analysis (EDA) of heterogeneous photocatalysis assays demonstrated that nSOD@CuONPs achieved 82% removal of a highly concentrated (70 L-1) binary mixture of Crystal Violet (CV) and Methylene Blue (MB) dyes after 240 min at an optimal concentration of 0.8 L-1 and neutral pH. The DL/CV model generated a 3D morphology with an acidity heat map, enabling the proposal of a comprehensive photocatalytic degradation mechanism under visible light, highlighting the critical role of Cu-based Lewis acid sites and the generated ROS in the degradation pathway. A subsequent kinetic study on the main byproduct, aniline, showed an 89.6% removal, confirming the promising photocatalytic activity of the nSOD@CuO-NPs for complete wastewater treatment.
