Search Results (1,248)

The use of aluminum alloys in aerospace is limited by their poor weldability, making many incompatible with additive manufacturing (AM) processes like powder bed fusion—laser beam metal (PBF-LB/M), known as well as laser powder bed fusion. This incompatibility hinders the fabrication of complex, lightweight components. To overcome this, Aluminum Metal Matrix Composites (AMMCs) are formed by mechanically alloying the non-processable Al6082 base alloy with ceramic reinforcements; subsequently, Titanium Carbide (TiC) and Silicon Carbide (SiC) particles are developed. This approach induces microstructural changes necessary for AM compatibility. The influence of varying reinforcement contents (1–5 wt.%) on powder homogeneity, microstructural evolution (via Energy Dispersive X-ray Spectroscopy and Electron Backscatter Diffraction), processability, and mechanical properties is systematically studied. The key finding is that metallurgical modification is a robust solution. TiC addition at 2 wt.% and 5 wt.% completely eliminated solidification cracking, achieving high processability. SiC substantially reduced cracking compared to the base alloy. These results demonstrate the potential of AMMCs to successfully translate conventional, non-weldable aluminum alloys into the realm of advanced additive manufacturing. Full article

In recent years, 3D printing has become a key technology for producing intricate geometries with high precision. Beta titanium alloys (β-Ti), due to their excellent combination of strength, ductility, low elastic modulus, and biocompatibility, are widely used in the aerospace and medical industries. However, the unique microstructure formed during additive manufacturing characterised by porosity, residual stress, and anisotropy can significantly influence the mechanical performance and durability of these materials. This study examines how different printing parameters affect porosity, dimensional stability, and mechanical properties in the β-Ti alloy Ti25Nb4Ta8Sn. The investigation focuses on thin-walled samples and gyroid structures, which represent model geometries for porous biomedical components. These structures, defined by a periodic network of interconnected channels, provide a useful platform for studying the relationship between geometry and mechanical response. In addition, the effects of surface etching on the morphology and compressive behaviour of printed gyroid structures were evaluated. Compression testing was used to determine how etching alters load-bearing performance and to identify correlations between surface modification and mechanical response. The combined analysis enables optimisation of both printing and post-processing parameters for advanced biomedical applications. Full article

Given the increasing human exposure to electromagnetic radiation of various frequen-cies, mostly in the microwave range, awareness of potential health problems caused by this radiation has begun to grow. New building materials are being developed and tested to prevent or limit the penetration of microwave radiation, especially those frequencies that are used in mobile telephony. In contrast with the majority of the available literature on the investigation of concrete (cement) materials, in this paper, clay composite materials with the addition of nanoparticles of antimony(III)–tin(IV) oxide, zinc ferrite, iron(III) oxide, and two crystal modifications of titanium dioxide (rutile and anatase) were prepared in order to examine their effect on the absorption of electro-magnetic radiation. Nanomaterials are characterized by different physical and chemical methods. Specific surface area (B.E.T.), thermal properties (TGA/DSC), phase composition (PXRD), morphology (SEM), and chemical and mineralogical composition (EDX, and ED–XRF,) were determined. Thermal conductivity of clay composites was tested, and these materials showed a positive effect on the thermal conductivity (λ) of the composite: a reduction of 10–33%. The reflection and transmission coefficients of microwave radiation in the frequency range used in mobile telephony (1.5–4.0 GHz) were determined. From these data, the absolute value of radiation absorption in the materials was calculated. The results showed that the addition of the tested nanomaterials in a mass fraction of 3 to 5 wt.% significantly increases the absorption (reduces the penetration) of microwave radiation. Two nanomaterials, Sb₂O₃·SnO₂ and TiO₂ (rutile), have proven to be particularly effective: the reduction in transmission is 30–50%. The results of the test were correlated with the crystal structures of the examined nanomaterials. The inclusion of titanium dioxide and antimony-doped tin oxide into the clay led to a significant enhancement in microwave electromagnetic radiation absorption, which can be attributed to their interaction with the dielectric and conductive phases present in clay-based building materials. Full article

Graphene-based nanomaterials, including graphene oxide (GO) and graphene quantum dots (GQDs), exhibit exceptional properties, which might facilitate the functional modification of TiO₂ nanotubes (NTs) for enhanced rapid osseointegration. This study investigated the effects of GO/GQD-deposited TiO₂-NTs on cell proliferation, osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs), and early osseointegration in male 6-week-old Sprague Dawley (SD) rats. TiO₂-NTs (control group) were fabricated on titanium substrates via anodic oxidation. GO and GQDs were electrochemically deposited onto the TiO₂-NTs using cyclic voltammetry with 0.5 mg/mL GO and 0.1 mg/mL GQD dispersions to form NT-GO and NT-GQDs. In vitro assays evaluated cell adhesion, proliferation, and osteogenic differentiation. Implants were randomly inserted into one femoral epiphysis of nine rats (n = 3), and osseointegration was evaluated using micro-computed tomography and sequential fluorescence labeling at 2, 4, and 6 weeks post-implantation. Statistical analysis was conducted using ANOVA. Cyclic voltammetry successfully synthesized NT-GO and NT-GQDs, with Raman spectra confirming D and G bands. Both NT-GO and NT-GQDs exhibited superior cell adhesion, proliferation, and enhanced osteogenic differentiation compared with TiO₂-NTs. Notably, the NT-GQDs significantly promoted new bone formation in vivo. The integration of graphene nanomaterials onto TiO₂-NTs improves biocompatibility and accelerates osteogenesis, suggesting a promising strategy for enhancing osseointegration in orthopedic and dental implants. Full article

Land desertification in the Agropastoral ecotone of arid and semi-arid regions poses significant threats to ecological security. Elucidating the geochemical characteristics and provenance of surface sediments is crucial for understanding desertification mechanisms and developing effective sand-control strategies. This study focuses on Kangbao County in the Bashang region of Hebei Province. We systematically collected 57 surface sediment samples from four geomorphic units: low mountains-hills, gently sloping hills, gully depressions, and undulating plains. Major and trace element concentrations were determined using X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). Elemental ratios, principal component analysis (PCA), and Non-metric Multidimensional Scaling (nMDS) were employed to decipher sediment geochemical signatures and provenance, emphasizing geomorphologically controlled source differentiation mechanisms. Key findings are as follows: (1) Geochemical characteristics reveal that sediment elemental enrichment or depletion patterns exhibit fundamental differences depending on the specific bedrock reference. When normalized against felsic versus mafic end-members, elements including Fe₂O₃, MgO, TiO₂, CaO, Cr, Ni, Co, V, Rb, and Ba demonstrate contrasting geochemical behaviors. (2) The sediments originate from a homogenized mixture derived from the weathering of regional bedrock, clearly distinct from the high-maturity aeolian sands of the Hunshandake Sandy Land. (3) The spatial geochemical differentiation of surface sediments follows a two-stage process: the initial formation of a homogenized sediment source from bedrock weathering products, followed by subtle modification through landform-specific geomorphic processes, resulting in weak but systematic geochemical variations across the landscape. Based on these findings, a zonal management strategy is proposed to disrupt the localized sediment cycle by intercepting sources in hilly areas, restoring gully depressions, and blocking aeolian pathways on the plains. This study provides a scientific basis for precise desertification control in Kangbao and supports ecological barrier enhancement for the Beijing–Tianjin–Hebei region. Full article

Microbial colonization is a major factor contributing to peri-implantitis, and creating durable glassy surfaces with antimicrobial agents such as silver and copper may reduce microbial accumulation on dental abutments. This study aimed to develop antimicrobial thin-film glassy surfaces on Ti6Al4V alloy and to evaluate their surface and mechanical properties, antimicrobial effectiveness, and biocompatibility before and after thermal aging. A sol–gel-derived glassy matrix (G) was synthesized, and two antimicrobial coatings were prepared by incorporating ionic Ag (GAg) or a combination of Ag/Cu (GAgCu). Ti6Al4V specimens; these were either left uncoated or dip-coated with G, GAg, or GAgCu and cured at 450 °C. Half of the specimens underwent thermal aging between 5 °C and 55 °C for 3000 cycles. Surface roughness, contact angle, hardness, adhesion strength, scratch resistance, cytotoxicity (Agar diffusion and MTT assay on L929 fibroblasts), and microbial adhesion were evaluated using Streptococcus sanguinis, Porphyromonas gingivalis, and Candida albicans as representative oral microorganisms. Both coatings exhibited low surface roughness, hydrophilic surfaces, improved hardness, and significantly reduced microbial adhesion for all tested species. GAg showed superior mechanical properties, whereas GAgCu demonstrated a relatively stronger antimicrobial effect. Cytotoxicity tests indicated that all coatings were biocompatible at levels suitable for oral use. Overall, these coatings demonstrated strong adhesion, durability, and antimicrobial activity, suggesting their suitability for dental abutments made of Ti6Al4V. Full article

Ti-6Al-4V, a popular biomedical alloy, is increasingly fabricated by additive manufacturing methods, like laser powder bed fusion (LPBF). However, rapid thermal cycling and steep temperature gradients often induce mechanical degradation, corrosion, and wear. To address these challenges, laser surface modification is explored. This study investigates the microstructure and corrosion behaviour (simulated body fluid, 37 °C) of LPBF and wrought Ti-6Al-4V after laser surface melting (LSM) treatment. LSM produced modified layers of 1250–1350 µm (LPBF) and 1530–1600 µm (wrought), with gradients from remelted dendrites to acicular martensite. Microhardness in the layers increased to 655–680 HV due to lattice expansion, crystallite refinement, and higher dislocation density. However, LSM-treated alloys showed higher corrosion rates and weaker passive films, attributed to increased surface roughness, martensite formation, residual stresses, and microstructural inhomogeneity. Aluminium silicate surface films/residues further compromised passivity. Nevertheless, both LSM-LPBF and LSM-wrought specimens displayed low corrosion current densities (10⁻⁴ mA/cm²), true passivity (10⁻³–10⁻⁴ mA/cm²), and high resistance to localised corrosion. After cyclic polarisation, rutile-rich TiO₂ surface films with aluminium silicate hydrates were observed. LSM-LPBF specimens showed slightly inferior general corrosion resistance compared to LSM-wrought counterparts, due to pronounced surface texture variations, phase/composition differences, higher microstrains and dislocation density. Full article

Oily wastewater poses severe ecological and health threats, but conventional separation technologies have limitations like low efficiency or high energy consumption. Herein, two superwettable carbon fiber (CF)-based membranes were fabricated for efficient oil–water separation. Using CF (low cost, excellent mechanical stability) as the substrate, Cu-TiO₂@CF (superhydrophilic/underwater superoleophobic, renewable) was prepared via a deep ultraviolet (DUV)-assisted sol–gel method, and OTMS/Cu-TiO₂@CF (superhydrophobic/superoleophilic) was obtained by modifying Cu-TiO₂@CF with octadecyltrimethoxysilane (OTMS) via hydrothermal synthesis. Characterization showed Cu-TiO₂ coatings uniformly covered CF, with strong substrate bonding. Both membranes exhibited outstanding performance: Cu-TiO₂@CF achieved water fluxes of up to 79,839.6 L·m⁻²·h⁻¹ and >97.3% separation efficiency for four oil–water mixtures; OTMS/Cu-TiO₂@CF had a maximum oil flux of 86,593.4 L·m⁻²·h⁻¹ and >98.1% efficiency. Cu-TiO₂@CF regenerated via 10 min UV irradiation (restoring underwater oil contact angle to 153°), while OTMS/Cu-TiO₂@CF achieved recovery through the process of UV irradiation followed by OTMS re-modification. Both membranes maintained stable performance over 100 cycles, demonstrating considerable potential for engineering applications. Full article

Redox flow batteries (RFBs) are an emerging class of large-scale energy storage devices, yet the commercial benchmark—vanadium redox flow batteries (VRFBs)—is highly constrained by a modest open-circuit potential (1.26 V) while posing an expensive and volatile material procurement costs. This review focuses on recent progress in diversifying redox-active species to overcome these limits, highlighting chemistries that increase overall cell voltage, energy density, and efficiency while maintaining long cycle life and safety. The study dwells deeper into manganese-based systems (e.g., Mn/Ti, Mn/V, Mn/S, M/Zn) that leverage Mn’s high positive potential while addressing Mn(III) disproportionation reactions; iron-based hybrids (Fe/Cr, Fe/Zn, Fe/Pb, Fe/V, Fe/S, Fe/Cd) that exploit the low cost, and its abundance, along with membrane and electrolyte strategies to prevent the potential issue involving crossover; cerium-anchored catholytes (Ce/Pb, V/Ce, Eu/Ce, Ce/S, Ce/Zn) that deliver high operational voltage by implementing an acid-base media, along with selective zeolite membranes; and halide systems (Zn–I, Zn–Br, Sn–Br, polysulfide–bromine/iodide) that combine fast redox kinetics and high solubility with advances such as carbon-coated membranes, bromine complexation, and ambipolar electrolytes. Across these various families of RFBs, the review highlights the modifications made to the flow-fields, membranes, and electrodes by utilizing a zero-gap serpentine flow field, sulfonated poly(ether ether ketone) (SPEEK) membranes, carbon-modified and zeolite separators, electrolyte additives to enhance the voltage (VE%), and thereby energy (EE%) efficiency, while reducing the overall system cost. These modifications to the existing RFB technology offer a promising alternative to traditional approaches, paving the way for improved performance and widespread adoption of RFB technology in large-scale grid-based energy storage solutions. Full article

High denitration efficiency and strong adaptability to flue gas temperature fluctuations are the core properties of the NH₃-SCR catalyst. In this study, Fe₂O₃ modification is used as a means to explore the mechanism of adding Fe₂O₃ to broaden the temperature range of the 6CeO₂-40MnO₂/TiO₂ catalyst during the preparation process. The results show that the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst exhibits excellent denitration performance, with a denitration efficiency higher than 90%. The temperature range is from 129 to 390 °C. N₂ selectivity and resistance to SO₂ and H₂O are good, and the denitration performance is significantly improved. When the Fe₂O₃ content is 6%, it promotes lattice shrinkage of TiO₂, improves its dispersion, refines the grain size, and increases the specific surface area of the catalyst. At the same time, Fe₂O₃ enhances the chemical adsorption of oxygen on the catalyst surface and increases the proportion of low-cost metal ions, thereby promoting electron transfer between active elements, generating more surface reactive oxygen species, increasing the oxygen vacancy content and adsorption sites for NO_x and NH₃, and significantly improving the redox performance of the catalyst. This effect is particularly conducive to the formation of strong acid sites on the catalyst surface. The NH₃-SCR reaction on the surface of the 6Fe₂O₃-6CeO₂-40MnO₂/TiO₂ catalyst follows both the L-H and E-R mechanisms, with the L-H mechanism being dominant. Full article

Photocatalytic pathogen inactivation is gaining increasing importance due to the rising number of microbial species resistant to conventional antibacterial agents. Titanium dioxide (TiO₂)-based photocatalysts have emerged as a promising solution, being not only potent antibacterial agents but also environmentally friendly and capable of simultaneously degrading organic pollutants. This review summarizes recent advances in the antibacterial performance of different TiO₂ modifications, including commercial nanopowders, nanoparticles with various morphologies, thin films, composites, and polymer-supported nanostructures, all primarily activated under UV light. Given the limited ability of pristine TiO₂ to harvest solar radiation, we also highlight the most recent strategies for designing visible-light-responsive TiO₂, such as doping, incorporation of plasmonic metal nanoparticles, formation of heterostructures, and interfacial charge transfer complexes. In addition, we discuss the fundamental structural features of TiO₂, the mechanisms of reactive oxygen species (ROS) generation involved in bacterial inactivation, and kinetic models describing antibacterial efficiency. These insights aim to advance the understanding and development of eco-friendly, cost-effective, and sustainable photocatalytic disinfection technologies. Full article

As a favorable hydrophilic additive for antifouling modification of polyvinylidene fluoride (PVDF) membrane, titanium dioxide (TiO₂) nanoparticles have been applied for years. Sodium dodecyl sulfonate (SDS), a representative anionic surfactant, has been proven to benefit the dispersion of nano-TiO₂ via an electro-spatial stabilizing mechanism. In this study, various proportionally SDS-functionalized TiO₂ nanoparticles were adopted to modify PVDF membrane. Dispersion and stability of SDS-functionalized TiO₂ nanoparticles in casting solutions were evaluated by multiple light scattering technology. The properties and antifouling performance of PVDF/SDS-TiO₂ composite membranes were assessed. The uniformity of surface pores as well as structures on cross-section morphologies was modified. The finger-like structure of PVDF/SDS-TiO₂ composite membrane was adequately developed at the SDS/TiO₂ mass ratio of 1:1. The improved antifouling performance was corroborated by the increasing free energy of cohesion and adhesion as well as the interaction energy barrier between membrane surfaces and approaching foulants assessed by classic extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory, the low flux decline during bovine serum albumin (BSA) solution filtration process, and the high critical flux (38 L/(m²·h·kPa)) in membrane bioreactor. This study exploits a promising way to modify PVDF membrane applicable to the wastewater treatment field. Full article

Metal–organic frameworks (MOFs) have been increasingly recognized as promising platforms for enzyme modulation, owing to their tunable porosity, high surface area, and versatile chemical functionality. In this review, the potential of MOFs for the inhibition and modulation of protein kinases and phosphatases—key regulators of cellular signaling and disease progression—is examined. The structural fundamentals of MOFs are outlined, followed by a discussion of common synthesis strategies, including solvothermal, microwave-assisted, sonochemical, and mechanochemical methods. Emphasis is placed on how synthesis conditions influence critical features such as particle size, crystallinity, surface chemistry, and functional group accessibility, all of which impact biological performance. Four primary mechanisms of MOF–enzyme interaction are discussed: surface adsorption, active site coordination, catalytic mimicry, and allosteric modulation. Each mechanism is linked to distinct physicochemical parameters, including pore size, surface charge, and metal node identity. Special focus is given to biologically relevant metal centers such as Zr⁴⁺, Ce⁴⁺, Cu²⁺, Fe³⁺, and Ti⁴⁺, which have been shown to contribute to both MOF stability and enzymatic inhibition through Lewis acid or redox-mediated mechanisms. Recent in vitro studies are reviewed, in which MOFs demonstrated selective inhibition of disease-relevant enzymes with minimal cytotoxicity. Despite these advancements, several limitations have been identified, including scalability challenges, limited physiological stability, and potential off-target effects. Strategies such as post-synthetic modification, green synthesis, and biomimetic surface functionalization are being explored to overcome these barriers. Through an integration of materials science, coordination chemistry, and molecular biology, this review aims to provide a comprehensive perspective on the rational design of MOFs for targeted enzyme inhibition in therapeutic contexts. Full article

Background/Objectives: Utilization of polyetheretherketone (PEEK) cages for spinal fusion has surged in the U.S., yet comprehensive comparisons evaluating its postoperative effectiveness with alternative materials remain limited. This systematic review investigates the efficacy of PEEK cages against traditional fusion materials across various surgery types, elucidating PEEK’s impact on fusion rates, postoperative outcomes, and long-term success. Methods: A systematic search of PubMed, CINAHL, Scopus, Embase, and Web of Science was conducted through 14 October 2024. Included studies were randomized controlled trials (RCTs) comparing PEEK cages with titanium, silicon nitride, and metal-coated PEEK cages for anterior cervical discectomy and fusion (ACDF), posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF). Article quality was assessed using GRADE criteria. Results: From 288 initially screened articles, 25 RCTs involving 2046 patients (mean follow-up 23.1 ± 18.2 months) met inclusion criteria and were determined as moderate (n = 21) or high (n = 4) quality. Fusion rates by cage material for PEEK (n = 1041), Ti-PEEK (n = 291), and titanium (n = 53) were 85.63 ± 18.00%, 80.05 ± 19.9%, and 92.75 ± 11.31%, respectively. In ACDF, titanium cages achieved higher fusion rates than PEEK (100% vs. 94%). In PLIF and TLIF, coated PEEK outperformed uncoated PEEK (75% vs. 71% and 94% vs. 84%, respectively). Uncoated PEEK achieved fusion rates of 94.04 ± 5.04% for ACDF, 71.21 ± 21.93% for PLIF, and 83.50 ± 24.66% for TLIF, with titanium outperforming PEEK in early fusion outcomes. Coated PEEK demonstrated potential improvements in fusion rates over uncoated PEEK in PLIFs and TLIFs. Conclusions: Selection of cage material for spinal fusions should be tailored to surgical requirements and patient needs. While titanium and PEEK are effective, their performance varies across contexts. New materials and surface modifications may enhance these outcomes further, warranting future research in long-term studies and development of novel materials. These findings can help surgeons choose cage materials according to procedure type, patient characteristics, and imaging needs. Full article

This paper systematically investigates the interaction between pipes and soil under geo-logical disaster conditions by combining small-scale physical experiments with mul-ti-method numerical simulations. Three analytical models—namely the Smoothed Particle Hydrodynamics-Finite Element Method (SPH-FEM) model, the traditional FEM model, and the soil spring-based Pipe–Soil Interaction (PSI) model—are employed to comparatively analyze their applicability across different geohazard scenarios. The study found that the PSI model overpredicted pipeline strain responses, indicating that traditional soil spring analytical models require modification. The traditional FEM model provided the most accurate predictions under small-displacement conditions, while the SPH-FEM model yielded more reliable results for large-displacement scenarios. The novelty of this study lies in its systematic exploration of the applicability of these three methodologies, providing scientifically grounded simulation tools for numerical modeling in engineering practice. Full article