Search Results (2,326)

Human-driven soil erosion is a signal of the widely debated “Anthropocene”. There is widespread controversy regarding the time consistency and time transgression of human-driven soil erosion in the Late Holocene. In this study, three well-dated cores, B10, B14 and W20 from west to east, spanning the past 4–6 ka from the Pearl River Estuary (PRE) shelf, southern China, were selected for elemental tests. Principal component analysis divides the elements into four components. The first principal component (PC1) includes TFe₂O₃, Al₂O₃, V, Cs, Rb, Ga, TiO₂, K₂O, Ta, Nb, MnO, Th, LOI, and Cl, being the proxy for fine-grained terrigenous input and watershed soil erosion. The PC1 variations in B10 and B14 reveal that erosion enhanced at ~2.2 ka BP, and less erosion occurred at ~1.5 ka BP but has intensified since ~1.2 ka BP, which is consistent with the simulated cropland area of the Pearl River Basin and lake records in the upper West River, southwestern China. However, the records from the W20 reveal a continuous increase in terrestrial input since 2.2 ka BP, which is consistent with the soil erosion changes recorded by the South China coast lakes at its provenance region. Hence, differences in the initial age of the signals of human activities were revealed in the PRE shelf system. Our study not only reveals the time transgression of the “Anthropocene” boundary but also updates the sediment source-to-sink model of the PRE shelf system. Full article

This study addresses the issue of rare earth (RE) resource wastage caused by the aggregation of the commonly used diffusion source, Dy, at the triangular grain boundary region during grain boundary diffusion (GBD). The approach involves Ti doping to refine the grain size and increase the volume fraction of RE₆Fe₁₃Ga, thereby improving the efficiency of Dy utilization. The results show that when 0.2 wt% Ti is doped, Dy diffusion is applied to the magnet, and the magnet achieves excellent magnetic properties, with Br = 14.03 kGs, Hcj = 20.24 kOe, Q = 0.96, and (BH)max = 47.15 MGOe. The coercivity shows an enhancement of 8.66 kOe compared to the pristine magnet. Research and analysis indicate that doping Ti into the magnet promotes the formation of the RE6Fe13Ga phase, leading to the creation of continuous thin grain boundaries that weaken the exchange coupling between adjacent grains. Additionally, the presence of RE₆Fe₁₃Ga suppresses the segregation of Dy in the RE-rich phases, encouraging its further incorporation into the main phase and improving Dy utilization. This study demonstrates that appropriate Ti doping can effectively optimize Dy distribution within the magnet, reduce its aggregation in the triangular grain boundary region, and promote its incorporation into the main phase. This significantly reduces the amount of Dy required and provides a feasible approach to enhancing the efficiency of heavy rare earth resource utilization, thereby offering a path to the design of high-performance GBD magnets. Full article

Medium-entropy alloys (MEAs) with a simple phase structure and nanoprecipitates have excellent mechanical properties and considerable potential for advanced structural applications. The current study investigated the effect of boron microalloying and thermomechanical treatment on the microstructure evolution and mechanical properties of Co₄₃Cr₁₅Ni₃₀Al₅Ti₇ and (Co₄₃Cr₁₅Ni₃₀Al₅Ti₇)_99.7B_0.3 MEAs. X-ray diffraction analysis revealed a single phase of face-centered cubic (FCC) structure in all as-cast samples. After cold rolling and recrystallization annealing were completed, a clear ordered FCC (L1₂) phase was observed concurrently with the FCC matrix. In the alloy doped with 0.3 at.% B, the grain size was refined from 600 to 200 nm. TEM analysis revealed a nano-sized L1₂ phase coherently embedded in the FCC matrix. Analysis of the mechanical properties of boron-doped MEA samples revealed that cold rolling to 80% thickness followed by annealing at 900 °C for 2 h and aging at 750 °C for 4 h yielded the best mechanical performance. Among all samples, the alloy doped with 0.3 at.% boron achieved an optimal combination of mechanical properties (yield strength: 1817 MPa; ultimate tensile strength: 2313 MPa; ductility: 14.5%). Full article

The preparation of the core–shell-like structured before hot working can significantly enhance the hot workability of the alloy. In order to research the properties of the alloy, the finite element method combined with the crystal plasticity constitutive theory was used to establish the finite element model of the core–shell-like structured TiAl alloy with (α₂ + γ) lamellae colonies as the core and α₂ matrix as the shell. The research focuses on the influence of the length and number of γ lamellae on the stress–strain distribution and the contribution of slip systems in each phase to the plasticity of the alloy. The results show that when the γ lamella length increases from 12 μm to 16 μm, the overall stress decreases by 12.0%; when the number increases from 6 to 10, the stress decreases by 7.7%. The stress reduction is primarily influenced by the α₂ phase. Increasing the volume fraction of γ lamellae facilitates stress distribution within the α₂ phase and enhances the plasticity of the material. In the γ phase O4, S1 and S7 slip systems contribute the most to the plastic deformation of the γ phase. In the α₂ phase, the B1 slip system is the main contributor to the plasticity of the α₂ phase. And the B1 slip system contributes more significantly to the plastic deformation of the entire model. Full article

Purpose: To explore the correlation between radiologic patterns on high-resolution computed tomography (HRCT) and circulating biomarkers of inflammation and endothelial activation in patients with COVID-19 pneumonia, with the aim of identifying imaging-biomarker phenotypes that may offer insights for clinical stratification. Materials and Methods: This prospective single-center study included 84 consecutive patients hospitalized with PCR-confirmed SARS-CoV-2 infection and respiratory failure. All underwent baseline HRCT, along with parallel biohumoral profiling, including inflammatory (IL-1Ra, IL-6, IL-10) and endothelial (Angiopoietin-2, sVCAM-1, sE-Selectin) biomarkers. HRCT scans were reviewed for parenchymal and vascular abnormalities (vascular tree-in-bud [TIB], vascular enlargement pattern [VEP]). Semi-quantitative scores were assigned for parenchymal (PS) and vascular (VS) involvement. Results: Patients with higher PS had significantly prolonged hospital stay (35 vs. 17 days; p = 0.014), increased ICU admission rates (68.8% vs. 21.4%; p = 0.003), and elevated serum levels of IL-1Ra, IL-6, and IL-10 (p < 0.05). At multivariable analysis, PS remained independently associated with ICU admission after adjustment for age, inflammatory burden, and comorbidities (p = 0.014). A high VS was associated with significantly increased Angiopoietin-2 levels (p = 0.036), although it did not directly correlate with ICU admission or mortality. A significant positive correlation was observed between PS and VS (r =0.392; p < 0.001). Conclusions: in this study, HRCT-based parenchymal and vascular patterns appear significantly correlated with biological processes occurring in severe COVID-19 pneumonia. These observations, although preliminary, may offer a conceptual basis for future studies exploring radiologic and biomarker-based stratification in severe respiratory infections. Full article

The Pantanos de Villa wetland, a protected Ramsar site in Lima, Peru, faces significant pressure from invasive species and urban pollution. This study provides a comprehensive evaluation of microhabitat use and trace-element bioaccumulation in the invasive crayfish Procambarus clarkii (Girard, 1852). We analyzed the physicochemical parameters of the microhabitat and measured the concentrations of macroelements (Na, Mg, P), trace metals (Cu, Zn, Al, Ni, Ti, Pb), and a metalloid (B) in water, sediment, and crayfish tissues (gill, hepatopancreas, and muscle) using ICP-OES. Additionally, we examined the growth pattern of P. clarkii through its length–weight relationships. A total of 171 individuals were recorded: 99 males and 72 females. Males were longer (13–15 cm), while females were heavier (18–21 g). Additionally, a positive correlation was observed in females between the size and weight of the hepatopancreas and abdominal muscle, whereas no significant link was found in males. Sediments had higher levels of the evaluated chemical elements, with Cu (28.26 mg kg⁻¹) and Zn (66.88 mg kg⁻¹) exceeding international quality guidelines, indicating a possible ecotoxicological risk. The significant negative correlation between dissolved oxygen and the abundance of P. clarkii suggests that higher D.O. is associated with less bioturbation and more predators, making the microhabitat less suitable for juveniles. We conclude that P. clarkii serves as an essential bioindicator and potential vector for the relocation of the trace in an urban wetland, highlighting the need for integrated management strategies to reduce the ecological impacts of this invasive species. Full article

Timing skew is a critical bottleneck in high-speed Time-Interleaved (TI) Analog-to-Digital Converters (ADCs) that severely degrades dynamic range. This paper presents a mathematically rigorous, data-driven synchronization framework for calibrating effective sampling timing in TI-ADCs based on the Kuramoto oscillator model. Conventional clock-alignment methods often fail to capture signal-path mismatches, such as sampling switch aperture delay, while correlation-based techniques suffer from signal-dependent “blind-spot” regions. Overcoming this fundamental limitation without analog complexity is achieved via a fully digital feedback loop where each sub-ADC channel is modeled as a coupled oscillator following discrete-time Kuramoto dynamics. Unlike traditional approaches that rely on auxiliary analog phase detectors, the proposed scheme utilizes the ADC outputs to estimate and correct the effective sampling instants directly. A Lyapunov-based stability analysis proves that global phase synchronization is guaranteed when the adaptive coupling strength exceeds a critical value $K_c$. Theoretical results show that the system ensures exponential convergence of phase alignment, driving the total inter-channel timing error toward zero without relying on input-signal statistics. Behavioral MATLAB R2025a simulations of a 12-bit, 4-channel, 10 GS/s TI ADC confirm the analytical predictions. The proposed Kuramoto-based calibration achieves a residual skew reduction of over 99% and an SFDR improvement of 55.12 dB compared to correlation-based methods, even at blind-spot input frequencies, while adaptively reducing digital control power through dynamic coupling adjustment. The study demonstrates that data-driven, synchronization-based calibration provides an input-independent, energy-efficient, and mathematically verifiable solution for system-level timing correction in TI ADCs. Full article

In this study, a material-driven strategy is presented to realize tunable triboelectric–electromagnetic hybrid generators while overcoming the form-factor limitations of conventional magnet-assisted systems. A magneto-dielectric hybrid generator (MDHG) was constructed using a soft magnetized dielectric composite, where NdFeB microparticles were embedded in an Ecoflex matrix and activated by pulse magnetization, allowing a single compliant layer to operate simultaneously as a triboelectric contact medium and a magnetic flux source coupled to a coil. The magnetic filler loading was systematically optimized to elucidate the trade-off between enhanced electromagnetic induction and a non-monotonic triboelectric response governed by dielectric polarization, surface potential, and interfacial energetics. To selectively strengthen the triboelectric branch without sacrificing electromagnetic output, nanoscale BaTiO₃ was introduced as an interstitial dielectric phase to promote polarization-active pathways and suppress screening-driven charge-utilization loss. Under contact–separation operation, the optimized MDHG produced triboelectric outputs up to a V_OC of 400.40 V and I_SC of 56.95 μA, while the electromagnetic branch delivered up to a V_OC of 260.04 mV and I_SC of 0.89 mA, corresponding to 2.87- and 2.62-fold increases in triboelectric V_OC and I_SC over pristine Ecoflex. Finally, the hybrid signatures enabled a wearable smart-skin interface capable of decoupling touch occurrence, intensity, and counter-material identity. Full article

To evaluate the potential of compound attractants in ameliorating diet-induced intestinal dysfunction in Siniperca chuatsi fed commercial compound feed, this study investigated their effects on intestinal metabolism and microbiota composition. In this study, four distinct diets are formulated: a control diet without attractants and three experimental diets supplemented with compound attractants A (nucleotides and L-glutamic acid), B (nucleotides, L-glutamic acid, and allicin), and C (nucleotides, L-glutamic acid, and betaine). Over a period of 8 weeks, groups of S. chuatsi were fed these diets, after which we assessed the intestinal microbiota and transcriptomic responses. KEGG pathway analysis of differentially expressed genes (DEGs) indicated that the A group exhibited significant changes predominantly in intestinal cholesterol homeostasis and inflammatory responses. The B group showed DEGs primarily associated with mucosal immune functions and pro-inflammatory cytokine signaling. Diversely, the C group revealed DEGs chiefly tied to immune and inflammatory response pathways. Furthermore, the intestinal microbiota exhibited beneficial modifications at both the phylum and genus levels in the A and B groups, while such beneficial shifts were not observed in the C group. These findings indicated that dietary supplementation with compound attractants A and B could positively influence both the intestinal transcriptomic landscape and microbiota composition in S. chuatsi, highlighting their potential as effective additives in compound feeds for aquaculture. Full article

The parametrization of the thermomechanical behavior of shape memory alloys (SMAs) under constant load is described in terms of their functional properties. The deformation–temperature–stress behavior of SMAs from various alloy systems—such as Ni-Ti, Ni-Ti-Cu, and Ni-Mn-Ga—was parametrized using a sigmoidal function. This approach enables the characterization of phase transformation parameters, including transformation temperatures, kinetic parameters, and the relationship between recoverable deformation and applied stress. It is shown that the sigmoid function can serve as a universal descriptor of thermoelastic phase transformations across different alloy systems and transformation types, such as B2–R–B19′–R–B2 (Ni-Ti-Cu), B2–R–B19′–B2 (Ni-Ti), and B2 (L2₁)–B19′ (L2₀)–B2 (L2₁). A correlation coefficient of approximately 0.99 was achieved. The present work extends the theoretical framework of diffuse martensitic transitions in SMAs, for which the sigmoid function has been theoretically derived to describe phase fractions. The article’s novelty lies in shifting from pure mathematical approximation (curve fitting) to physical parametrization of SMA behavior specifically under constant stress (actuator mode). Full article

The article considers issues related to improving the surface characteristics of titanium Gr2 using one of the lightest, cheapest and most ecological methods—electrospark deposition with low pulse energy and with ultradisperse electrodes TiB₂-TiAl with nanosized additives of NbC and ZrO₂. Using profilometric, metallographic, XRD, SEM and EDS methods, the change in the geometric characteristics, composition, structure, micro and nanohardness of the coatings as a function of the electrical parameters of the ESD regime has been studied. The results show that the use of TiB₂-TiAl electrodes and low pulse energy allows the formation of dense, continuous and uniform coatings that demonstrate a significant reduction in roughness, inherent irregularities and structural defects of electrospark coatings. Coatings with minimal defects, with crystalline–amorphous structures, with newly formed intermetallic and wear-resistant double and triple phases of the type AlTi₃, TiAl₃, TiB, TiN_0.3, Al₂O₃, AlB₂, TiC_0.3N_0.7, Ti_3.2B_1.6N_2.4, Al_2.86O_3.45N_0.55 have been obtained. Possibilities have been found for controlling and obtaining specific values for the roughness and thickness of coatings in the ranges Ra = 1.5–3.2 µm and δ = 8–19.5 µm, respectively. The electrical parameters of the modes ensure the production of coatings with previously known thickness and roughness, with increased microhardness up to 13 GPa, with the maximum possible content of deliberately synthesized high-hard phases and with ultra-fine-grained structures have been defined. Full article

Background: This study aimed to evaluate the effect of two shaping systems combined with different irrigant activation methods on the tridimensional distribution of a bioceramic root canal sealer. Methods: Sixty single, round, straight root canals from extracted human teeth were randomized into six groups (n = 10): A1–A3 shaped with RACE NiTi rotary files; B1–B3 shaped with an adaptive XP-Endo Shaper. NaOCl and EDTA irrigation was performed using passive ultrasonic irrigation (PUI, group 1), conventional endodontic needle irrigation (CENI, group 2), or XP-Endo Finisher mechanical activation (group 3). Canals were obturated using the single-cone cold gutta-percha technique with BioRoot RCS bioceramic sealer. Confocal laser scanning microscopy was used to assess sealer penetration (mean and maximum depths and percentage), and sealer integrity on canal walls at coronal, middle, and apical levels. Results: The XP-Endo Shaper combined with the XP-Endo Finisher showed the highest mean sealer penetration depth, while RACE with PUI had the lowest (B3 vs. B2 p = 0.02; vs. A1 p = 0.05). No significant differences were observed in the maximum penetration depth and percentage of penetration across groups. Sealer integrity was significantly lower in the RACE + XP-Endo Finisher group (p < 0.01). Coronal regions consistently showed higher mean and maximum sealer penetration and percentage of penetration compared to apical thirds, with no significant differences in sealer integrity within root regions. Conclusions: The combination of the XP-Endo Shaper and XP-Endo Finisher showed a tendency towards superior sealer tridimensional distribution, particularly in the middle and apical thirds. This in vitro study suggests that adaptive shaping instruments combined with mechanical activation enhance sealer distribution, potentially improving treatment success. Full article

Rapid removal of chemically diverse organic pollutants remains a major challenge in aqueous decontamination. In this study, atmosphere-controlled defect engineering was used to activate anatase TiO₂ as a rapid adsorbent operating on the minute scale, exhibiting low charge selectivity under the investigated conditions. A reduced black TiO₂ (B–TiO₂), produced by inert annealing, achieved ≈100% removal of cationic methylene blue within ~6 min and ≈91% uptake of anionic methyl orange within ~3 min, whereas pristine and air-annealed TiO₂ showed only marginal adsorption under identical conditions. Correlative structural and surface-sensitive analyses indicated that this behaviour was associated with a chemically activated near-surface region enriched in reduced titanium contributions, defect-associated or non-lattice oxygen environments and a locally perturbed anatase framework, together with finely dispersed carbon-related motifs integrated within the oxide matrix. Adsorption kinetics were described, within experimental resolution, by pseudo-second-order fitting, while intraparticle diffusion analysis supported sequential regimes initiated by rapid interfacial attachment. Equilibrium analysis yielded apparent maximum capacities of 6.116 mg g⁻¹ for methylene blue and 2.950 mg g⁻¹ for methyl orange, reflecting adsorption governed by surface heterogeneity for cationic species and an apparent saturation-type response for anionic uptake. Overall, controlled surface non-stoichiometry emerges as a viable strategy to enhance adsorption kinetics in TiO₂, providing a transferable design framework for developing oxide-based adsorbents for sustainable water-treatment applications. Full article

This work investigates the NiTi shape memory alloys fabricated via laser powder-directed energy deposition (LP-DED). The properties of NiTi alloys produced by powder metallurgy or additive manufacturing routes are strongly influenced by the type of feedstock material employed. Two powder feedstocks were used for DED fabrication: a blended mixture of elemental nickel and titanium powders with a nominal chemical composition of Ni56Ti44 (wt.%) and a pre-alloyed NiTi powder containing 55.75 wt.% Ni. Samples fabricated from both types of powders were subjected to microstructural characterization, phase composition analysis, and mechanical and corrosion testing. It was found that DED processing on a non-preheated CP-Ti substrate is prone to warping and that samples deposited from the elemental Ni and Ti powder mixture exhibited pronounced inhomogeneity of microstructure and mechanical properties along the build direction, accompanied by the formation of the Ti₂Ni secondary phase. The absence of a superelastic plateau was observed in the corresponding stress–strain response. On the contrary, the samples deposited from the pre-alloyed NiTi powder exhibited a microstructure composed of B2 and B19′ phases and already demonstrated a clear superelastic response in the as-built condition during tensile loading. Based on the tensile test results, this NiTi material was used only for superelasticity testing. The superelastic behavior was further enhanced by post-deposition heat treatment, which significantly increased the recovery rate from 53% to 89%. Full article

In alignment with the European Union’s 2050 carbon-neutrality targets, the automotive industry is intensifying efforts to adopt lightweight materials that ensure structural integrity without compromising safety. Press-hardened steels (PHS), offering a combination of ultra-high strength and formability, are at the forefront of these developments. Standard PHS grades rely on Ti–B microalloying; however, further alloying with Nb and V has been proposed to enhance hydrogen embrittlement resistance via microstructural refinement and hydrogen trapping. This study investigates hydrogen transport and mechanical degradation in a Ti–Nb–V microalloyed PHS compared to a conventional Ti-only 22MnB5 grade. Electrochemical permeation, thermal desorption, and mechanical testing were employed to characterize hydrogen diffusivity, solubility, and trapping mechanisms. The Ti–Nb–V variant demonstrated lower hydrogen diffusivity, higher solubility, and improved resistance to delayed fracture, attributable to the presence of fine NbTiV precipitates. Full article