Search Results (6,403)

Flexible strain sensors require both a responsive conductive network and a mechanically compliant supporting structure. In this study, a sandwich-structured carbon nanotube (CNT)/graphene–thermoplastic polyurethane (TPU) nanofiber strain sensor was fabricated by electrospinning, spray-coating, pre-stretching, and hot-pressing. Field-emission scanning electron microscopy was used to examine the nanofiber and coated-fiber morphology, while energy-dispersive X-ray spectroscopy was used only to describe elemental distribution. The electrical response was quantitatively evaluated under tensile deformation. The sensor exhibited piecewise gauge factors of approximately 47.3, 269.6, and 613.8 over strain ranges of 0–20%, 20–45%, and 45–60%, respectively. The response and recovery times were approximately 120 and 180 ms, and the electrical response remained observable over 5000 loading–unloading cycles at 20% strain. Qualitative demonstrations involving finger-bending, elbow-bending, pulse, grasping, walking, and repeated pressing produced distinguishable resistance-time patterns. These results indicate the potential of the CNT/graphene–TPU device for wearable deformation monitoring. Full article

Aluminum matrix composites (AMCs) reinforced with natural mineral ilmenite offer a cost-effective and thermally stable alternative to conventional cast iron brake drum materials. This study investigates the synergistic effect of fine (32–50 µm) and coarse (75–106 µm) ilmenite particles at four fine-to-coarse weight ratios (1:4, 2:3, 3:2, and 4:1) and three reinforcement contents (5, 10, and 15 wt.%) on the thermal stability and dry sliding wear behavior of stir-cast LM30 Al composites. Ilmenite reinforcement progressively reduces the coefficient of thermal expansion of the LM30 matrix, with the 15 wt.% 4:1 fine-to-coarse ratio composite (15DRP41) exhibiting the lowest coefficient of thermal expansion of ~16.54 × 10⁻⁶/°C, a ~33.3% reduction relative to the unreinforced alloy (~24.8 × 10⁻⁶/°C). The 15DRP41 composite demonstrates the lowest wear rate of all the fabricated composites, 1.82 × 10⁻³ mm³/m at 9.81 N and 9.56 × 10⁻³ mm³/m at 68.67 N at 200 °C. Under the most severe load condition (68.67 N, 200 °C), the coefficient of friction of 15DRP41 is reduced by up to 44% compared with the LM30 alloy. A comparative test against commercial grey cast iron shows that 15DRP41 has a similar wear rate up to 200 °C, while its density (~2.9 g/cm³) is significantly lower and it has excellent dimensional stability. Scanning electron microscopy and energy-dispersive X-ray spectroscopy of worn surfaces and debris confirm a progressive change from oxidative and mild abrasive wear at low loads and temperatures to severe wear by delamination at 68.67 N and 300 °C, as evidenced by the presence of a multi-component mechanically mixed layer. The results have confirmed that the optimum fine-to-coarse ratio for the reinforcement was 4:1, which led to the maximum wear resistance and thermal stability in ilmenite-reinforced LM30 composites for lightweight automotive brake drum applications, and that the optimum weight percentage for the reinforcement was 15 wt.%. Full article

Light pozzolanic soft clay has high compressibility and relatively poor structural stability, which limits its direct application in subgrade and foundation engineering. This study develops a sustainable combined stabilization–reinforcement system for lightweight volcanic ash soil using a steel slag–fly ash-based composite cementitious binder (GS) and recycled polyester fiber (RPF). Unconfined compressive strength tests, unconsolidated undrained triaxial tests, and microstructural characterization were conducted to evaluate the mechanical behavior and microstructural features of the treated soil. The results show that the GS binder markedly increased the soil strength, whereas RPF mainly improved specimen integrity and the post-peak response. Based on the single-additive and orthogonal test results, 24% GS, 0.6% RPF, and 9 mm fibers were identified as an appropriate mixture within the investigated factor levels for further mechanical evaluation. With the increase in confining pressure, the stress–strain response changes from strain softening to strain hardening. Scanning electron microscopy (SEM) observations showed fine particulate material at local particle-contact and fiber–matrix regions, while energy-dispersive X-ray spectroscopy (EDS) analysis identified a representative Ca-rich microregion containing Si and Al. The combined use of GS binder and RPF effectively improved the strength and deformation resistance of lightweight volcanic ash soft clay. Full article

A novel low-temperature method to synthesize a hybrid carbon material (HCM) is reported. The synthesis relies on a chemical vapor deposition (CVD) approach, using zeolite NaY as a scaffold structure and acetone as the carbon source. The deposition temperature was 500 °C at a pressure of 46 ± 1 kPa. Following the growth of the HCM, the material was treated with HF to remove the scaffold, and the resultant materials were characterized by high-resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray spectroscopy (EDS) mapping, transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman microscopy, and Brunauer–Emmett–Teller (BET) surface area analysis, showing heterogeneous morphology. The results demonstrate that synthesis at low temperatures produces a robust hybrid material that can adopt different configurations and/or morphologies by modifying the scaffold structure. Full article

Low-cost adsorbents derived from agricultural and livestock waste offer a sustainable approach to wastewater remediation. In this study, a material derived from cow dung ash (SMCDA) was prepared through a simple waste-valorization route without chemical activation and evaluated for the removal of methylene blue (MB) from aqueous solution. X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller analysis, and zeta-potential measurements were used to characterize the mineral composition, surface functional groups, morphology, pore structure, and surface charge of SMCDA. Batch adsorption experiments examined the effects of solution pH, adsorbent dosage, initial MB concentration, contact time, and temperature. The highest removal efficiency, 97.33%, was obtained at pH 8 with an SMCDA dosage of 1000 mg L⁻¹. Equilibrium data were fitted using seven isotherm models and evaluated using multiple statistical criteria and Multi-Objective Optimization by Ratio Analysis (MOORA). The Freundlich model achieved the highest MOORA ranking and predicted an equilibrium adsorption capacity of 13.944 mg g⁻¹ at the highest concentration investigated, which is close to the experimental value of 14.425 mg g⁻¹. The results are consistent with heterogeneous adsorption involving electrostatic attraction, possible π–π interactions, hydrogen bonding, and pore filling. These findings demonstrate the potential of cow dung ash as a low-cost adsorbent prepared without hazardous chemical activating agents. Full article

Quartz purity is essential for reliable optically stimulated luminescence (OSL) dating, yet the mineralogical evolution of sediment samples during extraction is rarely documented at each preparation stage. This study uses scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) to characterise two loess samples from the Urluia section, Dobrogea, Romania, across sixteen successive stages of a standard OSL quartz extraction protocol. Four compositional indices—the Quartz Purity Index (QPI), Feldspar Contamination Index (FCI), Heavy Mineral Index (HMI), and Carbonate Index (CI)—are introduced to quantify purification efficiency. Each preparation stage played a different role: HCl treatment primarily removed carbonates, grain-size separation and density fractionation reduced heavy minerals by ~99%, and feldspar removal resulted from the combined effects of density separation and HF etching. Despite identical protocols, two samples collected from stratigraphically adjacent positions showed markedly different HF etching efficiencies, reaching ~94% and ~66% quartz purity, respectively. However, luminescence measurements showed similarly weak feldspar signals in both samples, with intensities substantially lower than the quartz OSL signal. These results demonstrate that purification efficiency cannot be assumed to be uniform across loess samples in Romania and highlight SEM-EDS as a practical quality-control tool for OSL sample preparation. Full article

The aim of this study is to synthesize zinc oxide nanoparticles (ZnO NPs) using G. globosa aqueous leaf extract. The preliminary screening of the phytochemicals was performed with the G. globosa aqueous leaf extract. The physical and chemical characteristics of G. globosa-mediated ZnO NPs were evaluated using UV-Vis spectroscopy, Fourier-transform infra-red spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), nanoanalysis and thermogravimetry. The antibacterial activity of G. globosa-mediated ZnO NPs was assessed against Gram-negative bacteria. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) analyses were performed to evaluate the antibacterial efficacy of the G. globosa-mediated ZnO NPs. The heavy metal adsorption capacity of the synthesized ZnO NPs was evaluated using atomic adsorption spectroscopy (AAS). The UV-Vis spectrum of G. globosa-mediated ZnO NPs proved the excitonic absorption of the synthesized ZnO NPs. FTIR analysis determined the presence of metal oxide functional groups in the G. globosa-mediated ZnO NPs. The average size of 60 nm and the spherical shape of G. globosa-mediated ZnO NPs were confirmed by HRTEM and SEM analyses. The synthesized ZnO NPs had prominent antibacterial activity against Klebsiella pneumoniae and Escherichia coli. G. globosa-mediated ZnO NPs acted as an important adsorbent of heavy metals such as cadmium and lead. Adsorption kinetic studies (pseudo-first-order and pseudo-second-order kinetics) and isotherm analyses (Langmuir and Freundlich models) were performed. The kinetic studies and isotherm models revealed that the synthesized ZnO NPs showed higher adsorption efficiency for cadmium. Full article

Biogas slurry can enhance soil fertility, but the heavy metals it contains may pose potential ecological risks to soil-crop systems. To mitigate heavy metal pollution resulting from the application of biogas slurry to soil, this study investigated potential remediation strategies through the use of blended biochar application. In this study, soil incubation experiments were conducted to evaluate the immobilization performance of cow dung biochar (CB), corn straw biochar (SB), and blended biochar (cow dung + corn straw) (C3S7, C5S5, and C7S3) toward Pb, Zn, Ni, Cr, Cu, As, and Cd under different biogas slurry ratios (Z0, Z1:8, and Z1:4). The results concluded that immobilization efficiency consistently followed the order C7S3 ≥ C5S5 > C3S7 > CB ≈ SB, indicating that the blended biochar generally outperformed the two single biochar in the biogas slurry-irrigated soil system. Batch adsorption experiments showed that adsorption of all metals was better described by the pseudo-second-order model (R² > 0.94). Isotherm fitting further indicated that Zn, Ni, Cr, Cu, and Cd were better fitted by the Langmuir model, whereas Pb and As were better fitted by the Freundlich model. Physicochemical characterization, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM–EDS), and Fourier transform infrared spectroscopy (FTIR) analyses collectively suggested that the superior performance of blended biochar was associated with the integration of mineral-related characteristics from CB and surface chemical properties from SB, which together enhanced the synergistic fixation of coexisting metals. Consistently, biochar application reduced the potential ecological risk index (RI) of bioavailable heavy metals in soil, with blended biochar showing lower RI values than CB and SB. C7S3 exhibited the best performance in all treatments, highlighting the potential of blended biochar as an effective amendment for mitigating multi-metal pollution risks with biogas slurry utilization. Full article

In this study, brick plant waste was used to produce alkali-activated mortars. Four mixtures with identical compositions but different mixing sequences and curing methods were prepared. Two were conventionally produced using a pre-cooled 10 M potassium hydroxide (KOH) solution and sodium silicate (Na₂SiO₃), with one cured at ambient conditions and the other at an elevated temperature. The remaining two used modified mixing sequences to utilize internally generated heat for curing (direct KOH powder addition and addition of KOH dissolved in water immediately before mixing). The influence of mixing sequence and curing method on mechanical properties and high-temperature performance was evaluated after exposure to 600 °C through residual flexural and compressive strengths, mass loss, and visual examination of specimen cross-sections. The two best-performing mortars were further characterized by Fourier-transform infrared spectroscopy (FT-IR) and field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (FE-SEM-EDS), while the mixture combining favorable high-temperature performance with simple preparation was additionally analyzed for thermal conductivity and specific heat capacity. The conventionally prepared, elevated-temperature-cured mixture exhibited the lowest room-temperature flexural and compressive strengths (2.7 and 12.9 MPa, respectively) but the best high-temperature performance, with flexural and compressive strength increases of 14.8% and 10.9%, respectively, after exposure to high temperature. Visual assessment may suggest some degree of structural densification in this mixture and in the mixture prepared by direct addition of KOH powder to the dry components, whereas the other two mixtures may exhibit signs of partial weakening in the interfacial transition zone (ITZ). Among the internally cured mixtures, direct KOH powder addition produced slightly better room- and high-temperature performance than adding KOH dissolved in water immediately before mixing. FT-IR and FE-SEM-EDS confirmed the formation of potassium and sodium aluminosilicate hydrate, (K,N)-A-S-H, gel in the conventionally prepared, elevated-temperature-cured mixture and the mixture with direct KOH powder addition. The nearly unchanged compressive strength of the KOH-powder-based mixture was associated with a high retention of thermal conductivity (93%) and specific heat capacity (80%) after high-temperature exposure. Full article

The interfacial reaction between solder and substrate is a critical factor governing joint reliability, making it essential to understand the formation and stability of interfacial reaction layers when developing new high-temperature lead-free solders. This study investigates the interfacial reaction layers formed in Zn-5Al-3Mg solder/Cu substrate joints soldered at 693 K under vacuum. With a binary Zn-Al solder, the Cu substrate is progressively consumed by Zn, and the intermediate phases CuZn₄, Cu₅Zn₈, and CuZn nucleate and grow concurrently at the solder interface. The addition of a minor amount of Mg to the Zn-Al alloy, however, fundamentally alters this reaction sequence. Transmission electron microscopy analyses, including scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy (STEM-EDS), energy-filtered TEM (EF-TEM), and electron diffraction, reveal three distinct interfacial layers: an outer Mg₂Zn₁₁ layer, a middle two-phase mixture of CuZn₄/Mg₂CuZn₃, and an inner Cu₅Zn₈ layer adjacent to the Cu substrate. The biphasic CuZn₄/Mg₂CuZn₃ mixture layer is shown to form via a quasi-peritectic reaction governed by sequential four-phase equilibria in the Zn-Mg-Cu ternary system. These findings demonstrate that minor Mg additions redirect the interfacial reaction pathway between Zn-Al-based solders and Cu substrates, providing new insight for the design of high-temperature Pb-free solder systems. Full article

A novel orthophosphate compound, BaNb_0.5In_0.5(PO₄)₂ (FA31), was investigated as a corrosion inhibitor for mild steel in 1.0 M HCl using electrochemical techniques, adsorption studies, and surface characterization. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) measurements demonstrated that the inhibition efficiency increased with inhibitor concentration, reaching a maximum value of 94.8% at the optimal concentration. The charge-transfer resistance (Rct) increased significantly from that of the uninhibited solution to 427.2 Ω·cm² in the presence of FA31, indicating the formation of a protective interfacial layer that effectively suppressed the corrosion process. The adsorption of FA31 on the mild steel surface followed the Langmuir adsorption isotherm, while the calculated standard Gibbs free energy of adsorption (ΔG°ads) indicated that the inhibition process was predominantly governed by physisorption. SEM/EDS analyses further confirmed the formation of a compact and homogeneous protective film on the steel surface. The combined electrochemical and surface analyses demonstrate that FA31 is an effective and environmentally promising corrosion inhibitor for mild steel in acidic media. Full article

Thin Bi₂Se₃ films were successfully electrodeposited from a non-aqueous ethylene glycol-based electrolyte and subsequently underwent thermal treatment in an Ar atmosphere to improve crystallinity. The phase and compositional properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. XRD and Raman analyses confirmed the formation of crystalline rhombohedral Bi₂Se₃, while FTIR measurements indicated minor surface oxidation. The electrical and semiconductor properties of the films were investigated through current–voltage and temperature-dependent conductivity measurements. The activation energy associated with intrinsic conduction was determined to be 0.25 eV, while the temperature sensitivity coefficient and temperature coefficient of resistance were found to be 2903 K and 0.032–0.013 K⁻¹, respectively. Infrared photoconductivity measurements in the wavelength range of 2800–4000 nm revealed a pronounced photoresponse near the band-gap energy of Bi₂Se₃. The obtained results demonstrate the potential of electrodeposited Bi₂Se₃ thin films for infrared-sensitive semiconductor and optoelectronic applications. Full article

This study describes the microstructural and chemical characteristics of luster glazes applied to white clay and chamotte clay bodies using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS) and X-ray diffraction (XRD). Surface and cross-sectional analyses were performed to evaluate glaze morphology, the glaze–body interface, and the formation of metallic phases responsible for the luster effect. SEM observations indicated that the glaze applied to the white clay body exhibited greater thickness uniformity and a well-defined transition zone. In contrast, the chamotte clay body, due to its higher porosity, showed a more heterogeneous glaze distribution and increased interfacial irregularities. EDS analyses revealed the localized distribution of metallic elements, particularly silver and copper, and demonstrated the influence of body composition on glaze–body interactions. XRD results confirmed the presence of silver- and copper-rich crystalline phases on the glaze surface. Overall, the results demonstrate that the optical and esthetic performance of luster glazes depends on both glaze formulation and the microstructural properties of the ceramic body, providing relevant insights for optimizing artistic and industrial applications. Full article

Background: Peri-implantitis is a chronic condition that reflects an interaction between local tissue destruction, systemic inflammation and corrosion-related implant alterations. This preliminary prospective exploratory clinical study aimed to characterize the systemic cytokine profile of patients with advanced peri-implantitis requiring explantation and to explore associations between clinical severity, cytokine behavior and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX)-defined corrosion-related findings. Methods: Thirteen patients with active advanced peri-implantitis were included. Probing depth and cone-beam computed tomography (CBCT)-based bone loss were assessed at four implant surfaces. Peripheral blood was collected before and 4 weeks after explantation. Serum interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-12p70 (IL-12p70), tumor necrosis factor alpha (TNF-α), high-sensitivity C-reactive protein (hsCRP), and fibrinogen were analyzed. Explanted implants underwent SEM/EDX assessment and were classified according to the presence or absence of SEM/EDX-defined corrosion-related findings. Results: IL-6 showed the strongest and most consistent associations with clinical and radiographic severity, whereas hsCRP and fibrinogen were not similarly related. Cytokines did not show a uniform post-explantation decrease after explantation. SEM/EDX-defined corrosion-related findings were not associated with higher baseline cytokines, but exploratory subgroup analysis suggested a divergent TNF-α trajectory. Conclusions: These findings suggest that IL-6 may reflect the clinical inflammatory burden of advanced peri-implantitis, while corrosion-related findings may be associated with post-explantation TNF-α behavior. Larger controlled studies are required. Full article

The combined use of ceramic waste powder (CWP) as a supplementary cementitious material and magnetized water (MW) as mixing water represents a promising strategy for producing sustainable concrete with reduced cement consumption while maintaining mechanical performance and durability. However, the synergistic effects of burnt ceramic waste powder (BCWP) and unburnt ceramic waste powder (UBCWP) combined with MW, particularly under aggressive environmental conditions, remain insufficiently investigated. This study evaluates the influence of BCWP and UBCWP, used as partial replacements for ordinary Portland cement (OPC) at replacement levels of 10%, 20%, and 30% by weight, together with conventional tap water (TW) and MW produced using a dual-field magnetic device (0.9 T and 1.5 T). A total of fourteen concrete mixtures were investigated through compressive strength tests at 7, 28, and 120 days; indirect tensile and flexural strength tests at 28 and 120 days; sulfate resistance after 120 days of MgSO₄ immersion; residual strength after thermal exposure at 200 °C; and microstructural characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The results indicate that increasing the CWP replacement level progressively reduced the mechanical properties of concrete; however, MW consistently mitigated these reductions by promoting cement hydration and producing a denser cementitious matrix. The mixture containing 20% BCWP with MW achieved a 120-day compressive strength comparable to that of the TW control, demonstrating that cement consumption can be reduced without compromising structural performance. Furthermore, MW mixtures exhibited significantly improved durability, with compressive strength losses of only 16–28% after sulfate attack compared with up to 42% for TW mixtures, and 1–13% after thermal exposure compared with up to 53% for TW mixtures. SEM and XRD analyses confirmed the development of denser microstructures with enhanced C–S–H gel formation in MW–CWP concretes. Overall, the findings demonstrate that the synergistic combination of ceramic waste powder and magnetized water provides an effective strategy for producing sustainable concrete with enhanced long-term mechanical performance, improved durability under aggressive environmental conditions, and reduced environmental impact. Full article