Search Results (4,576)

Here, a highly sensitive and selective electrochemical sensor for dopamine (DA) determination in pork was developed. This sensor was fabricated using iron-based nanocomposites (Fe@(C-S-N)) to modify a glassy carbon electrode (GCE) substrate. The Fe@(C-S-N) nanocomposites were synthesized through a facile low-temperature chemical precipitation approach by adopting ferrous sulfate and melamine as raw materials, with their structural and compositional properties thoroughly investigated using multiple analytical techniques, including X-ray diffraction (XRD), electron microscopy (EM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectra (EDS). Cyclic voltammetry (CV), chronocoulometry (CC), and differential pulse voltammetry (DPV) were adopted to investigate the electrochemical performance of the fabricated Fe@(C-S-N)/GCE sensor. Notably, the sensor demonstrated a linear response range from 0.05 to 100 μM with a minimal limit of detection (LOD) of 46 nM. Lastly, the fabrication sensor was used to determine DA in pork samples, showing an acceptable recovery of over 96.89%. Thus, the proposed sensor could offer an effective method for determining DA in pork. Full article

Control over chemical reactivity remains a fundamental challenge in synthesis chemistry, where targeting a specific reactant represents the ultimate goal. While photoactivation is a well-established approach for selective excitation, electron-induced chemistry offers a complementary pathway with high efficacy. In this study, we investigate the effects of low-energy electron irradiation on prototypical chlorobenzene/water molecular films, demonstrating that chlorobenzene can be selectively dissociated via a resonant process occurring at ~1 eV. At higher electron energies (>6 eV), multiple reaction pathways become accessible, including the fragmentation of both water and chlorobenzene molecules. Our study provides a perspective strategy for achieving reagent-specific control in complex molecular assemblies via low-energy electrons, offering new insights into electron-driven surface chemistry and reaction dynamics at the molecular level. Full article

Oily wastewater is a critical environmental concern, and the high costs and fouling of conventional membranes drive the search for low-cost, efficient alternatives. This study evaluates surface-modified quartz particles for oil–water separation, focusing on hydrophilic and hydrophobic coatings. Quartz samples underwent washing, hydrophobic coating, and hydrophilic coating, with morphological and elemental changes assessed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS). Oil and grease (O&G) content was determined via the EPA 1664 method under high-solids conditions. The untreated oil–water mixture contained 142,955.9 mg/L O&G. Hydrophilic-coated quartz achieved the greatest reduction, producing water with only 751.3 mg/L O&G, indicating excellent oil rejection and water selectivity. Washed quartz performed similarly at 837.1 mg/L. Hydrophobic-coated quartz, while yielding higher residual oil in water (64,198.9 mg/L), demonstrated strong oil affinity, making it more suitable for oil recovery applications. Raw quartz, tested without heavy oil loading, showed a baseline of 13.4 mg/L. These results confirm that surface engineering of quartz enables tunable separation properties, where hydrophilic surfaces favor water purification and hydrophobic surfaces enhance oil capture. The findings provide a pathway for scalable, cost-effective, and application-specific oily wastewater treatment solutions. Full article

There is limited research that addresses microplastics (MPs) contamination on the surfaces of fruits and vegetables. This study quantifies and characterizes MPs on the surface of tomatoes, apples, grapes, and cucumbers purchased from three markets (A, C, L). MPs were examined by stereomicroscopy, hot needle tests, and Scanning Electron Microscopy with Energy Dispersion Detector (SEM-EDX), and the results were reported by abundance, shape, color, and composition. Grapes in market A had the highest surface MPs concentration with a maximum of 0.891 particles/mm², while tomatoes in the same market had the lowest, at 0.030 particles/mm². The majority of MPs (> 85%) were transparent. Tomato, grape, and cucumber surfaces in all markets predominantly contained fragments, while apple surfaces primarily contained fibers. SEM-EDX analysis revealed MPs were primarily composed of carbon and oxygen and provided insights into the surface structures, elemental compositions, and sizes. Exposure assessment revealed the highest estimated daily intake (EDI) occurred in grapes from market A, at 9.24 × 10⁻⁵ MPs/kg/day for adults and 4.04 × 10⁻⁴ MPs/kg/day for children. Although the values appear low, no regulatory limits exist. Surface contamination remains an overlooked exposure route, emphasizing the need for food safety policies addressing MPs contamination and their effect on human health and the environment. Full article

In view of the need to increase the durability of working tools exposed to intense friction, this study analysed hybrid coatings (TiAlCN, AlTiCN, AlCrTiN, TiN, CrN) with a DLC (Diamond-Like Carbon) layer, deposited using PVD (Physical Vapour Deposition) methods (arc evaporation and magnetron sputtering). The structural characteristics of the coatings were determined using SEM (Scanning Electron Microscope) and AFM (Atomic Force Microscope) microscopy, as well as Raman spectroscopy, which confirmed the compact structure and amorphous nature of the DLC layer. Tribological tests were performed using a ball-on-disc test, revealing that DLC hybrid coatings significantly reduce the coefficient of friction (stabilisation in the range of 0.10 to 0.14 due to DLC graphitisation), limiting tool wear even under increased load. The SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy) microscopic examination revealed that the dominant wear mechanisms are abrasive and adhesive damage, and the AlCrTiN/DLC system is characterised by low wear and high adhesion (L_c = 10⁵ N), making it the optimal configuration for the given loads. Microhardness tests showed that high hardness does not always automatically translate into increased wear resistance (e.g., the AlTiCN coating with 4220 HV showed the highest wear), while coating systems with moderate hardness (TiAlCN/DLC, CrN/DLC) achieved very low wear values (~0.17 × 10⁻⁵ mm³/Nm), which highlights the importance of synergy between the hardness of the sublayer and the low friction of DLC in the design of protective coatings. Full article

Room-temperature sodium–sulfur (RT Na-S) batteries hold great potential in the field of large-scale energy storage due to their high theoretical energy density and low cost of raw materials. However, the inherent low conductivity, notorious shuttling, and sluggish kinetics of cathode materials cause the loss of active substances and capacity delay, hindering the practical application of RT Na-S batteries. Owing to their low cost, variable oxidation states, and unsaturated d orbitals, transition metal (TM)-based catalysts have been extensively studied in circumventing the above shortcomings. Herein, the review first elaborates on the reaction mechanisms and current challenges of RT Na-S batteries. Subsequently, the role and function mechanism of TM-based catalysts (including single/dual atoms, nanoparticles, compounds, and heterostructures) in RT Na-S batteries are described. Specifically, based on the theories of electronic transfer and atomic orbital hybridization, the interaction mechanism between TM-based catalysts and polysulfides, as well as the catalytic performance, are systematically discussed and summarized. Finally, a discussion on the challenges and future research perspectives associated with TM-based catalysts for RT Na-S batteries is provided. Full article

This study investigates the effects of welding parameters and the addition of a buffer layer on the morphology, microstructure, mechanical properties, and corrosion resistance of the overlay layer during overlay welding. This paper uses Q235 steel as the base material, ER309L as the buffer layer, and ER347 as the overlay layer to conduct process experiments on overlay welding component, aiming to obtain optimal process parameters. The effects of welding line energy and weld bead overlap rate on the morphology, dimensions, and dilution rate of the overlay layer were analyzed. Furthermore, the influence of the presence or absence of the buffer layer on the microstructure, mechanical properties, and corrosion resistance of the overlay layer was investigated. The microstructure and morphology of the overlay layer were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Mechanical and electrochemical tests were also performed to evaluate the mechanical and corrosion resistance properties of ER347 stainless steel weld overlays. The results showed that the optimal process parameters were successfully obtained, which ensured sound weld bead formation while minimizing dilution. The addition of the buffer layer (ER309L) improved the bonding quality of the overlay welding component interface, reduced element dilution in the overlay layer, significantly improved hardness distribution, and reduced sudden changes in hardness in the fusion zone, thereby optimizing the mechanical properties of the ER347 stainless steel overlay layer. After adding the buffer layer, the corrosion current density decreased from 6.23 × 10⁻⁵ A·cm⁻² to 2.21 × 10⁻⁵ A·cm⁻², and the corrosion potential increased from −1.049 V to −0.973 V, effectively reducing the corrosion risk of the overlay component. This study innovatively introduced a buffer layer in the process of overlay welding austenitic stainless steel on low-carbon steel and investigated the impact of the overlay welding process on the overlay layer, thereby contributing to a comprehensive understanding of the overlay welding process from multiple perspectives. Full article

Inorganic lead halide perovskite semiconductor materials exhibit great potential in the optoelectronic field due to their excellent optical and electrical properties. However, lead toxicity and limited material stability hinder their commercial applications. Consequently, the pursuit of non-toxic, stable alternatives is imperative for the sustainable development of halide-perovskite semiconductors. Non-toxic germanium-based halide perovskites, as promising candidates, have attracted considerable attention. Here, we present a systematic first-principles investigation of the structural, electronic, elastic, and optical properties of cost-effective germanium-based halide perovskites NaGeX₃ (X = Cl, Br, I). Energy and phonon-spectrum calculations demonstrate that NaGeX₃ with the R3c space group exhibits the highest structural stability, rather than the commonly assumed cubic phase. Hybrid functional calculations reveal that the band gaps of R3c NaGeX₃ decrease monotonically with increasing halogen radius, that is, 4.75 eV (NaGeCl₃) → 3.76 eV (NaGeBr₃) → 2.69 eV (NaGeI₃), accompanied by a reduction in carrier effective masses. Additionally, mechanically stable R3c NaGeX₃ exhibits lower hardness and ductility than that of the cubic phase. Optical properties indicate that NaGeX₃ materials have strong absorption coefficients (>10⁶ cm⁻¹) and low loss in the photon energy range of 9–11 eV, suggesting that such cost-effective germanium-based halide perovskites can be used in various optoelectronic devices in the ultraviolet region. Full article

The depletion of fossil fuels and the rise of environmental concerns have increased the importance of renewable energy sources, positioning wind energy as a key alternative. Modern wind turbine blades are predominantly manufactured from composite materials due to their light weight, high strength, and resistance to corrosion. In offshore applications, approximately 95% of the composite content is glass fiber-reinforced polymer (GFRP), while the remaining 5% is carbon fiber-reinforced polymer (CFRP). GFRP is favored for its low cost and fatigue resistance, whereas CFRP offers superior strength and stiffness but is limited by high production costs. This study investigates the durability of adhesively bonded GFRP and CFRP joints under marine exposure. Seven-layer GFRP and eight-layer CFRP laminates were produced using a 90° unidirectional twill weave and prepared in accordance with ASTM D5868-01. Specimens were immersed in natural Aegean Sea water (21 °C, salinity 3.3–3.7%) for 1, 2, and 3 months. Measurements revealed that GFRP absorbed significantly more moisture (1.02%, 2.97%, 3.78%) than CFRP (0.49%, 0.76%, 0.91%). Four-point bending tests conducted according to ASTM D790 showed reductions in Young’s modulus of up to 9.45% for GFRP and 3.48% for CFRP. Scanning electron microscopy (SEM) confirmed that moisture-induced degradation was more severe in GFRP joints compared to CFRP. These findings highlight the critical role of environmental exposure in the mechanical performance of marine composite joints. Full article

Improving the anaerobic digestion (AD) of swine manure is crucial for sustainable waste-to-energy systems, given its high organic load and process instability risks. This study examined the combined effects of substrate-to-inoculum ratio (SIR, 0.1–3.2) and magnetite-mediated direct interspecies electron transfer on biogas production, effluent quality, and microbial community dynamics. The highest methane yield (262 ± 10 mL CH₄/g COD) was obtained at SIR 0.1, while efficiency declined at higher SIRs due to acid and ammonia accumulation. Magnetite supplementation significantly improved methane yield (up to a 54.1% increase at SIR 0.2) and reduced the lag phase, particularly under moderate SIRs. Effluent characterization revealed that low SIRs induced elevated soluble COD (SCOD) levels, attributed to microbial autolysis and extracellular polymeric substance release. Furthermore, magnetite addition mitigated SCOD accumulation and shifted molecular weight distributions toward higher fractions (>15 kDa), indicating enhanced microbial activity and structural polymer formation. Microbial analysis revealed that magnetite-enriched Syntrophobacterium and Methanothrix promoted syntrophic cooperation and acetoclastic methanogenesis. Diversity indices and PCoA further showed that both SIR and magnetite significantly shaped microbial structure and function. Overall, an optimal SIR range of 0.2–0.4 under magnetite addition provided a balanced strategy for enhancing methane recovery, effluent quality, and microbial stability in swine manure AD. Full article

Electronic transport through T-shaped double quantum dots (TDQDs) connected to normal metallic leads is studied theoretically by using a nonequilibrium Green’s function method. It is assumed that the Coulomb interaction exists only in the central QD (QD-1) sandwiched between the leads, and it is absent in the other reference QD (QD-2) side-coupled to QD-1. We also consider the impacts of Majorana bound states (MBSs), which are prepared at the opposite ends of a topological superconductor nanowire (hereafter called a Majorana nanowire) connected to QD-2, on the electrical current and differential conductance. Our results show that by the combined effects of the Coulomb interaction in QD-1 and the MBSs, a negative differential conductance (NDC) effect emerges near the zero-bias point, where MBSs play significant roles. Now, the electrical current decreases despite the increasing bias voltage. The NDC is prone to occur under conditions of low temperature, and both of the two QDs’ energy levels are resonant to the leads’ zero Fermi energy. Its magnitude, which is characterized by a peak-to-valley ratio, can be enhanced up to 3 by increasing the interdot coupling strength, and it depends on the dot-MBS hybridization strength nonlinearly. This prominent NDC combined with the previously found zero-bias anomaly (ZBA) of the differential conductance is useful in designing novel quantum electric devices, and it may also serve as an effective detection means for the existence of MBSs, which is still a challenge in solid-state physics. Full article

The aim of the present note is to contribute to the search for sustainable binders to be used for soil stabilization purposes. Fly ash and quicklime are added to a clayey soil of low plasticity in different proportions; samples were prepared by wet mixing and Standard Proctor compaction of the soil–water–binder mixture. Permeability tests were carried out for the first 28 days of curing, varying the moulding water content of the investigated samples. Compressibility was evaluated through one-dimensional consolidation tests performed after 7 days of curing and shear strength was investigated at the same curing time. Reactions development was successfully monitored by measuring pH and small strain shear modulus by means of bender elements testing for the first 28 days of curing. Microstructural investigation through scanning electron microscope and Energy dispersive X-Ray Spectroscopy revealed the presence of pozzolanic products in the mixture, reflecting the reduction in compressibility and the improvement in the mechanical characteristics of the soil of concern, after the treatment. The addition of the combination of fly ash and quicklime allowed to enhance the draining capability of the mixtures, especially when the mixture is compacted at optimum water content. Full article

Traditional X-ray fluorescence computed tomography (XFCT) suffers from issues such as low photon collection efficiency, slow data acquisition, severe noise interference, and poor imaging quality due to the limitations of mechanical collimation. This study proposes to design an X-ray fluorescence imaging system based on bilateral Compton cameras and to develop an optimized reconstruction algorithm to achieve high-quality 2D/3D imaging of low-concentration samples (0.2% gold nanoparticles). A system equipped with bilateral Compton cameras was designed, replacing mechanical collimation with “electronic collimation”. The traditional LM-MLEM algorithm was optimized through improvements in data preprocessing, system matrix construction, iterative processes, and post-processing, integrating methods such as Total Variation (TV) regularization (anisotropic TV included), filtering, wavelet-domain constraints, and isosurface rendering. Successful 2D and 3D reconstruction of 0.2% gold nanoparticles was achieved. Compared with traditional algorithms, improvements were observed in convergence, stability, speed, quality, and accuracy. The system exhibited high detection efficiency, angular resolution, and energy resolution. The Compton camera-based XFCT overcomes the limitations of traditional methods; the optimized algorithm enables low-noise imaging at ultra-low concentrations and has potential applications in early cancer diagnosis and material analysis. Full article

The development of portable and wearable electronics has promoted the advancement of fiber supercapacitors (FSCs), but their low energy density still limits their application in flexible devices. Herein, we incorporated micron-sized graphene dispersions at varying concentrations into the polyaniline (PANI) precursor solution prepared via electrochemical polymerization and subsequently electrodeposited PANI/graphene composites onto the surface of carbon nanotube (CNT) fibers, ultimately obtaining fibrous PANI/graphene@CNT composite electrodes. This electrode material not only exhibits the superior electrochemical activity characteristic of conducting polymers synthesized by electrochemical polymerization but also possesses a relatively high specific surface area. Furthermore, we fabricated coaxial fiber supercapacitors using PANI/graphene@CNT composite fibers and CNT films as the positive and negative electrode materials, respectively. The maximum energy density and power density could reach 160.5 µWh cm⁻² and 13 mW cm⁻² respectively, proving its excellent energy storage and output capabilities. More importantly, the prepared CFASC device showed remarkable mechanical and electrochemical durability. Even after 3000 bending cycles, it retained 89.77% of its original capacitance, highlighting its promising applicability in the realm of flexible electronics. The resulting devices demonstrate excellent electrochemical performance and mechanical stability. Full article

With the advent of novel scintillators featuring higher atomic numbers and enhanced radiation hardness, these materials exhibit potential applications under high-dose-rate irradiation. In this work, we systematically compared the photon output characteristics of ten mainstream or emerging inorganic scintillators under high-dose-rate irradiation with low-energy (0.1–1.7 MeV) electrons or protons. Initially, under electron irradiation among ~0.1 to ~50 rad/s, responses exhibited saturation trends to varying degrees, with their variations conforming to the saturation model proposed. However, under proton irradiation among ~5 rad/s to ~150 rad/s, responses exhibited sigmoidal trends due to competition between radiation-induced defects and luminescence centers. Through dynamic derivation of carriers and them, a triple-balance model that demonstrated close agreement with such variations was established. Subsequently, energy-dependent responses under proton irradiation exhibited marked nonlinearity, which were well fitted by Birks’ law, confirming the validity of our measurements. In contrast, electron-induced responses remained nearly linear with increasing energy. Then, after high-dose-rate and prolonged irradiation, BGO revealed highest response degradation, while YAG(Ce) demonstrated most radiation-damage resistance. Moreover, Ce-doped scintillators displayed higher afterglow levels after prolonged irradiation, particularly for YAG(Ce). In summary, these experimental analyses can provide critical guidance for material selection and effective calibration of scintillator detectors operating under high-dose-rate radiation from charged particles. Full article