Search Results (4,655)

Background/Objectives: Biologic therapies are the cornerstone of severe asthma management. However, evidence regarding switching between biologics in children with severe asthma remains limited. Methods: Retrospective observational study including patients aged 6–17 years with severe asthma, followed at our tertiary referral center, who switched biologic therapy. Clinical, laboratory, and lung function data were collected at the initiation of the second biologic (T0) and after 4 (T1) and 12 months (T2). Changes in asthma control, exacerbation rate, inhaled corticosteroid dose, FeNO and lung function were evaluated. Results: Eight patients who switched and had been treated with a second biologic for at least 12 months were included. Switching occurred from omalizumab to dupilumab (n = 1), mepolizumab to dupilumab (n = 5), and mepolizumab to omalizumab (n = 2). The main reason for switching was inadequate asthma control, while one patient switched because of poorly controlled comorbidity. At T2, exacerbations significantly decreased (p = 0.03), with significant improvements in FEV₁ (p = 0.002) and FEV₁/FVC (p = 0.015). The daily fluticasone-equivalent dose decreased from a median of 500 μg to 425 μg. Conclusions: In this cohort, switching biologic therapy was associated with improved clinical and functional outcomes, with a significant response already detectable after 4 months. These findings highlight the importance of close clinical and functional monitoring to identify children who may benefit from a change in biologic therapy. Larger prospective studies are needed to define standardized criteria and optimal timing for biologic switching in pediatric severe asthma. Full article

The high-value recovery of valuable components from spent LiFePO₄ (LFP) batteries is of considerable significance for both resource recycling and environmental conservation. This study systematically investigates the simultaneous sulfuric acid leaching of Li, Fe, and P from spent LFP cathode materials, integrating process optimization with kinetic analysis. The effects of acid concentration, temperature, and stirring speed on the leaching behavior of Li, Fe, and P were evaluated to elucidate the underlying kinetic mechanisms. The results demonstrated that under optimal conditions—namely, a sulfuric acid concentration of 2.0 mol/L, a leaching temperature of 60 °C, and a stirring speed of 300 r/min—the leaching rates of Li, Fe, and P all exceeded 99.5%. Kinetic analysis revealed a diffusion-controlled leaching mechanism well described by the Avrami model, with a selective dissolution sequence of Li > Fe > P. The leaching of Li, Fe, and P exhibited apparent activation energies of 9.56 kJ/mol, 14.83 kJ/mol, and 12.82 kJ/mol, respectively. These findings provide theoretical support for the leaching and resource recovery of Li, Fe, and P from spent LFP cathode materials. Full article

Despite extensive research on iron-based metal matrix composites (Fe-based MMCs), an integrated assessment linking fabrication methods, reinforcement architectures, interface engineering, and strengthening mechanisms remains limited. This review summarizes recent advances in Fe-based MMCs, with emphasis on the relationships among processing routes, microstructural evolution, reinforcement characteristics, and mechanical performance. Powder metallurgy, casting, and additive manufacturing are critically compared in terms of their processing characteristics, advantages, limitations, and suitability for iron-based systems. The effects of reinforcement size, morphology, distribution, and volume fraction on composite performance are discussed. Particular attention is given to interface engineering strategies and architectured core–shell reinforcements produced through in situ reactions and solid-state diffusion, infiltration, laser cladding, sol–gel coating combined with additive manufacturing, electrochemical synthesis, and high-energy ball milling. Recent studies indicate that core–shell architectures can offer enhanced control of reinforcement–matrix interactions by combining hard ceramic or carbide phases with more ductile metallic components. Rod-like Me@MeC/Fe (Me = Ta, Nb, W) architectures and dispersed core–shell particles show promising combinations of strength, toughness, and wear resistance, although their performance depends strongly on shell architecture, interface characteristics, and processing conditions. Remaining challenges include reproducible and scalable fabrication, shell architecture control, interface stability, and long-term performance. Further progress may benefit from advanced reinforcement design, additive manufacturing, modelling, and AI-assisted optimization of high-performance Fe-based MMCs. Full article

Feldspar and quartz are essential ceramic raw materials, with feldspar acting as a flux and quartz as a structural filler. Feldspathic sand derived from granitic masses of the eastern Arabian Shield represents a promising local source. This study evaluates upgraded granitic detritus, commercially termed silspar, from the Khurs granite of the Dawadimi terrane. Twenty-five samples were chemically and technologically characterized; one compositionally anomalous sample (S2) was retained in the analytical tables for transparency but excluded before resource-level statistical preprocessing. Pearson correlation, principal component analysis and Ward hierarchical clustering were applied to 24 representative samples using eight chemical variables, while shrinkage, loss on ignition (LOI), whiteness (L*) and water absorption were used for external technological validation. Four chemistry-defined groups were identified: S1 and S3 form a dark impurity-rich pair; S4–S9 form the cleanest ceramic-grade group; S10–S13, S15–S17 and S24 define a transitional Ca-Fe-influenced group; and S14, S18–S23 and S25 form a more coherent potassic group. The firing variables differ significantly among the chemistry-defined groups under the standardized laboratory procedure. The results support controlled ceramic use of the representative Khurs-derived silspar, subject to stockpile homogenization and impurity control. Because phase proportions are normative estimates rather than direct XRD determinations, the work is presented as an integrated preliminary industrial-mineral screening assessment rather than a complete quantitative mineral-phase characterization. Full article

During the balanced cantilever construction of long-span composite box-girder bridges with corrugated steel webs (CSWs), eccentric construction loads induce restrained torsion in addition to bending and shear. If this torsional contribution is not adequately accounted for, the resulting warping normal stresses in the concrete slabs and shear stresses at the CSW–slab interfaces may be significantly underestimated—particularly during stages when the cantilever section remains partially open and torsional stiffness is reduced. Although restrained torsion has been extensively studied for prismatic or fully closed box sections, the response of variable-depth composite girders with CSWs under asynchronous pouring construction (APC)—where the cantilever tip may be temporarily unclosed—has not been systematically clarified. To address this gap, this study proposes an equivalent modeling approach that incorporates the orthotropic characteristics of CSWs. Based on the restrained-warping theories of Umanskii and Vlasov, the governing differential equations for an eccentrically loaded cantilever are derived and solved via a finite-difference scheme with appropriate end-boundary conditions, yielding closed-form expressions for warping normal and shear stresses. The proposed analytical method is validated against three-dimensional finite-element (FE) simulations of an actual bridge. The validated FE model is then used to simulate the cantilever erection process, systematically evaluating the effects of construction scheme, diaphragm casting sequence, and critical APC stages on the torsional response. Results indicate that the equivalent CSW model accurately captures the torsional behavior of variable-depth composite girders. Restrained torsion from eccentric loading produces substantial secondary stresses: warping normal stresses in the bottom and top slabs reach up to 26% and 18% of their bending counterparts, respectively, whereas warping shear stresses in the CSWs account for approximately 22% of the shear stress. Torsional resistance is highly sensitive to the construction method; APC sequences, in particular, induce highly variable warping stresses near the cantilever tip, where eccentric loading should be avoided. Critical-stage analysis further reveals that the long-cantilever stage with an unclosed section represents the most vulnerable condition, owing to abrupt changes in torsional stiffness and local stress concentrations at the end-section transition. Internal diaphragms promote a more uniform distribution of warping deformation from the fixed support to the cantilever end; accordingly, it is recommended that each diaphragm be cast promptly upon completion of its corresponding segment. Overall, the proposed analytical–numerical framework offers a practical tool for rapid restrained-torsion assessment, identification of critical construction stages and regions, control of eccentric construction loads, and rational selection of diaphragm casting sequences—thereby supporting construction-stage risk mitigation for long-span bridges with CSWs. Full article

The coarse Fe-containing intermetallics (IMCs) induced by excessive Fe levels seriously degrade the mechanical and corrosion properties of recycled aluminum alloys. Controlling the nucleation and growth behavior has been confirmed as effective in refining the Fe-containing intermetallics (IMCs) and enhancing the ductility of recycled aluminum alloys. In this work, the modification mechanism of Al–Ti–B in Al–2Fe alloy was systematically investigated by combining SEM microstructure, TEM characterization and DFT calculations. TEM observations reveal that TiB₂ particles are preferentially embedded within Al₁₃Fe₄ phases, forming coherent or semi-coherent interfaces, which act as nucleation sites and facilitate the refinement and uniform distribution of Fe-containing IMCs. Interface property calculation results show that the Al₁₃Fe₄ (620)/TiB₂ (01$\stackrel{\mathrm{-}}{1}$1) interface exhibits lower lattice mismatch (4.4%) and interface energy, indicating stronger interfacial bonding and higher interface stability. The electronic structure results showed that the enhanced interface stability is attribute to the pronounced charge redistribution. Stable interface structure reduces the heterogeneous nucleation barrier and promotes refinement efficiency of Fe-containing ICMs. This study provides theoretical guidance for the refinement of Fe-containing impurity phases and high-performance sustainable recycling of aluminum alloy scrap. Full article

CaCl₂-assisted Direct Reduction of Chromite (DRC) is a potentially lower energy alternative to conventional chromite smelting to produce ferrochrome (FeCr). This study investigates the technical feasibility of substituting petroleum coke (PC) with bio-carbon (BC) as the reductant in DRC and quantifies its effects on reduction behavior, alloy characteristics, and residual phase evolution. Chromite pellets containing CaCl₂ flux and either PC or BC were reduced under controlled conditions using thermogravimetric analysis and electric tube furnace experiments with continuous off-gas monitoring. Products were characterized using various methods including 3D X-ray microtomography, Scanning Electron Microscope (SEM)-based quantitative mineralogy, and Wavelength Dispersive Spectrometry using an Electron Probe Microanalyzer (WDS-EPMA). BC accelerated reduction kinetics relative to PC due to its devolatilization, which generated a microporous network and increased the reactive surface area. Correspondingly, peak CO flux occurred 8 min earlier with BC during vertical tube furnace tests. BC also produced finer FeCr alloys, with 15% of alloy volume below the initial reductant particle size compared with 3% for PC, reflecting enhanced alloy densification. Alloy compositions using both reductants met high-carbon FeCr specifications. BC use also promoted the formation of non-olivine and Cl-bearing slag phases, indicating that reductant type can influence the partitioning behavior of non-alloying elements within slag phases. Full article

Desertification is a major environmental problem in drylands, resulting from the interaction between climatic and anthropogenic factors and involving processes such as vegetation loss and soil erosion. In northeastern Brazil, long-term land-use pressure has intensified the vulnerability of semi-arid landscapes, leading to severe degradation and reduced environmental resilience. Within this context, the Salitre River Basin (Bahia State) represents a particularly relevant area for investigating desertification, as it combines a history of intense human pressure and soil degradation with arid climatic conditions recently recognized through climatological assessments. This study investigates the micromorphological organization, hillslope dynamics, and environmental degradation of carbonate soils of the Salitre river basin, aiming to reconstruct pedogeomorphological evolution and identify indicators of desertification. A toposequence-based approach was applied using ten soil profiles distributed across sectors with contrasting erosion intensity. Soil horizons were characterized through field descriptions, physical and chemical analyses, and micromorphological observations of thin sections. Soils are predominantly eutrophic, carbonate-rich, shallow Calcisols, with very high CaCO₃ contents (500–900 g kg⁻¹), alkaline pH, and low total organic carbon. The spatial organization of profiles results from strong lithological and geomorphological controls, with well-developed horizons in stable sectors, whereas truncated and homogeneous profiles occur in areas affected by severe erosion. Micromorphological features, including planar and moldic voids, Fe–Mn nodules, calcite coatings, and needle calcite infillings, indicate active carbonate dissolution/redistribution processes under increasing seasonality and aridity (calcification). The coexistence of inherited dissolution and recent precipitation features suggests polyphasic pedogenesis linked to Holocene climatic oscillations. The preservation of well-developed needle-fiber calcite is consistent with prolonged water-deficit conditions, although its precise chronological significance remains unconstrained in the absence of direct dating. At landscape scale, these processes are associated with hillslope retreat and dense networks of linear erosion, defining a scenario of severe land degradation. Full article

Benzophenone-3 (BP-3), an organic UV filter extensively applied in sunscreens, cosmetics and daily plastic products, is classified as a typical emerging endocrine-disrupting micropollutant. This compound is highly susceptible to bioaccumulation in aquatic organisms, triggers coral bleaching, and incurs oxidative damage to algae, fish and invertebrates. Conventional wastewater treatment processes cannot efficiently eliminate BP-3 from aqueous media, thereby imposing severe ecological risks on freshwater and marine ecosystems. In this study, iron-impregnated biochar (Fe-BC) was synthesized via an impregnation–pyrolysis route using powder of cultivated Chlorella pyrenoidosa (green microalga) as raw feedstock. Batch adsorption experiments revealed that iron impregnation remarkably enhanced the removal efficiency of BP-3. The maximum Langmuir saturated adsorption capacity of Fe-BC reached 91.7 mg/g, considerably exceeding the value of 51.5 mg/g for pristine biochar. Kinetic data exhibited favorable fitting with the pseudo-first-order kinetic model, demonstrating that Fe-BC rapidly captures BP-3 and achieves adsorption equilibrium within 120 min. Solution pH exerted a prominent influence on adsorption performance: the material maintained high BP-3 adsorption capacity at pH 7–10, whereas adsorption capacity declined drastically under strongly acidic (pH < 5) and extreme alkaline conditions (pH > 10.5). Fourier-transform infrared spectroscopy (FTIR) validated the successful loading of iron species onto the biochar surface, as well as the binding of BP-3 onto Fe-BC. Combined with pH-controlled experimental results, hydrogen bonding, hydrophobic interactions, and pore-filling effects are inferred as the dominant adsorption mechanisms for BP-3 removal. Furthermore, Fe-BC retained favorable BP-3 removal performance in simulated seawater matrices, endowing it with preliminary potential for wastewater treatment in coastal zones and tourist scenic areas. This work offers basic laboratory insights into BP-3 adsorption, while further verification concerning environmental low-concentration conditions, authentic water matrices, material reusability and stability is essential for its practical application. Full article

Heavy liquid metals such as liquid lead (Pb) are attractive heat transfer media for advanced energy applications, despite their corrosive nature. In the search for heat-resistant austenitic materials that are corrosion resistant to liquid Pb at high temperature, three new Fe24Ni15Cr3Al-based alumina-forming austenitic (AFA) steels with slightly varying compositions have been developed. The present study investigates the corrosion behavior of these AFA materials using static exposure tests to molten Pb containing 1 × 10⁻⁷ wt.% dissolved oxygen. The corrosion tests are performed at 500 °C, 600 °C, and 700 °C for 1000 h, 2000 h, and 5000 h each. In addition to the variation in material, temperature, and exposure time, two different surface finishes are also used for the tests. Examination of the specimens after exposure shows the formation of oxide scales for temperatures up to 600 °C on all three AFA materials, with minor material-specific variations. Furthermore, the scale characteristics depend on the surface finish. Coarse ground surfaces exhibit thin Al-rich protective oxide scales, while fine ground surfaces show the formation of thick multilayer oxide scales susceptible to Ni dissolution and Pb penetration. Pb exposure at 700 °C leads to a severe corrosion attack of all three Fe24Ni15Cr3Al-based AFA steels. Full article

The Fe–6.5 wt.% Si alloy is a promising soft magnetic material for electric motor applications owing to its high electrical resistivity and low core loss. However, the intrinsic brittleness of this alloy precludes fabrication of thin laminates using conventional rolling processes. Laser Powder Bed Fusion (LPBF) has therefore been considered as an alternative manufacturing route, offering both geometric flexibility and the inherent advantages of additive manufacturing. Nevertheless, successful LPBF processing of Fe–6.5 wt.% Si has remained challenging due to its high-silicon content. In this study, the Fe–6.5 wt.% Si alloy was modified by introducing 1 wt.% Cr, and LPBF process variables were optimized to yield defect-free parts. The effect of Cr addition on suppressing the disorder–order phase transformation during solidification was investigated through Thermo-Calc^® thermodynamic simulations and quantified via X-ray diffraction phase analysis. Crack morphology analysis from optical micrographs revealed a marked reduction in both solidification and liquation cracks, attributed to the role of Cr in mitigating silicon segregation and consequently lowering the fraction of ordered phases. Preheating the build plate to 200 °C was found to effectively eliminate vertical cracks by reducing thermal stresses within the parts; however, a limited number of horizontal cracks initiated at the sample edges and propagated inward, likely due to elevated thermal gradients at the perimeter. To address this issue, sacrificial walls were introduced at distances of 1.0 mm and 0.2 mm from the cube edges, locally reducing the cooling rates and effectively increasing the primary dendrite arm spacing (PDAS). The reduced cooling rate also led to lower lattice misorientation, confirmed by electron backscatter diffraction (EBSD), and a significant decrease in the crack length from ~2 mm to ~0.7 mm. Full article

Na₄Fe₃(PO₄)₂P₂O₇ (NFPP), an iron-based mixed phosphate–pyrophosphate cathode material, has emerged as one of the most commercially promising candidates for large-scale sodium-ion battery (SIB) energy storage applications. Its exceptional characteristics—an ultralow volume change of less than 4% during Na⁺ de/intercalation, a three-dimensional open framework enabling rapid ionic diffusion, and the use of earth-abundant, low-cost iron as the redox center—collectively deliver a unique combination of structural stability, rate capability, and economic viability. However, the fundamental challenge of phase-purity control, arising from the three-phase thermodynamic competition among NFPP, electrochemically inert maricite-NaFePO₄, and Na₂FeP₂O₇ during synthesis, critically limits its electrochemical performance. This review provides a systematic overview of NFPP research progress from 2012 to 2026, covering crystal structure and sodium storage mechanisms, synthesis methodologies, and—most critically—Phase Adjustment and modification strategies including non-stoichiometric regulation, defect engineering, elemental doping, anionic substitution, and heterostructure design. Mechanistic insights into how each strategy addresses the phase-purity challenge and enhances electrochemical kinetics are critically examined. Industrialization progress, full-cell performance evaluation, cost analysis, and future research directions toward practical deployment are also discussed. Full article

Existing comparative studies on metallic mild steel dampers (SDs) and fluid viscous dampers (FVDs) are primarily limited by the coupling of device type with layout variations, the lack of a unified performance metric, and the absence of multi-level evidence under fixed structural configurations. This study overcomes these limitations by comparing SDs and FVDs under strictly identical conditions—same RC frame, same 26 damper locations, same ground motions, and a unified code-specified drift target—across frequent, design-basis, and rare earthquake levels, supplemented by energy dissipation and added damping ratio analyses. Under frequent earthquakes (FEs), the FVD achieves a maximum story-shear reduction of 33% and effectively controls inter-story drift through its velocity-dependent energy-dissipation mechanism. Under rare earthquakes (REs), the SD demonstrates superior performance, providing a 35% maximum story-shear reduction, while maintaining inter-story drift ratios within code-specified limits, owing to its combined stiffness and damping contributions. In terms of energy dissipation, the total cumulative energy dissipated by FVDs is 39.4–67.6% higher than that of SDs under the same ground motions, with added damping ratios averaging 2.42% for FVDs and 2.86% for SDs. These findings suggest that FVDs are more favorable for serviceability and frequent seismic performance, while SDs exhibit better response reduction effects under rare earthquake excitations. Full article

Phosphogypsum (PG) produced by different wet-process phosphoric acid routes exhibits distinct mineralogical characteristics and metal ion release behaviors, which may influence its environmental risk and resource utilization potential. In this study, PG generated from the hemihydrate–dihydrate (HH-DH) and dihydrate (DH) processes was systematically investigated to elucidate the occurrence states, distribution characteristics, and leaching behavior of metal ions. Particle size distribution analysis, water-leaching experiments, Advanced Mineral Identification and Characterization System (AMICS), and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) were employed to characterize the particle size distribution, mineral composition, elemental distribution, and mineral liberation behavior before and after leaching. The results showed that gypsum was the dominant mineral phase, while quartz and phosphorus-containing gypsum (PCG) were the major impurity minerals. K and Na mainly occurred in soluble mineral phases and exhibited high leaching rates, whereas Al, Fe, and Mg were primarily associated with relatively stable insoluble minerals and showed limited leaching behavior. After water leaching, the particle size distribution shifted toward finer particles, accompanied by decreases in gypsum content and mineral liberation degree, especially in HH-DH phosphogypsum. Significant differences in mineral association, metal occurrence states, and ion release behavior were observed between HH-DH and DH phosphogypsum. These findings provide a mineralogical basis for impurity removal, water washing pretreatment, environmental risk control, and the resource utilization of phosphogypsum. Full article

This work investigated the extraction behavior of Zn, Cu, and Fe during sulfuric acid leaching of metallurgical waste from the Ust-Kamenogorsk zinc production plant. At the same time, the detailed kinetic analysis was restricted to Zn dissolution. This study aimed to determine the structural and morphological characteristics of metallurgical wastes and the extraction efficiencies of Zn, Cu, and Fe, and to evaluate the apparent kinetics of Zn dissolution comparatively. The phase composition of the initial and mechanically treated samples was studied by X-ray diffraction analysis, functional groups by FTIR spectroscopy, and morphological features by scanning electron microscopy. Leaching experiments were conducted to assess the effect of sulfuric acid concentration, temperature, and process duration. The results showed that mechanical treatment produced qualitative morphological and structural changes in the slag and was accompanied by improved extraction of Zn, Cu, and Fe during sulfuric acid leaching. The extraction behavior depended on the experimental variable investigated. In the sulfuric acid concentration series, extraction from the mechanically treated sample reached 70.55 ± 0.88% for Zn, 90.50 ± 0.47% for Cu, and 42.37 ± 0.47% for Fe at 1.0 M H₂SO₄. In the leaching time series conducted at 1.0 M H₂SO₄ and 75 °C, Zn extraction reached 78.06 ± 0.92% at 120 min after mechanical treatment, whereas Cu extraction reached its maximum of 90.78 ± 0.55% at 60 min. The time-dependent extraction behavior differed among the investigated metals, and no single leaching time maximized Zn, Cu, and Fe extraction simultaneously. Comparative analysis using Shrinking Core Model expressions indicated that both surface-reaction and product-layer-diffusion expressions provided comparable descriptions of the Zn leaching data; however, the limited number of kinetic data points does not allow definitive identification of a unique rate-controlling mechanism. For Zn dissolution, the apparent activation energies were 8.16 and 10.17 kJ mol⁻¹ for the surface chemical reaction expression and 14.37 and 17.81 kJ mol⁻¹ for the product-layer diffusion expression before and after mechanical treatment, respectively. A conceptual leaching pathway based on the available experimental observations was proposed to relate the observed structural and morphological changes to Zn extraction and the formation of a gypsum-containing solid residue. The results indicate that mechanical treatment is a promising pretreatment approach for improving the hydrometallurgical processing of the investigated metallurgical waste under the tested conditions. Full article