Search Results (4,773)

Electric bicycles are popular due to their environmental benefits and convenience. However, electric bicycle fires caused by series arc faults remain a serious safety concern. This study focuses on series arc fault identification for electric bicycles under complex operating conditions, covering state of charge (SoC), torque, and speed variations, and simultaneously considers normal state, DC-side series arc fault, and AC-side series arc fault conditions. Five time-domain features, namely root mean square (RMS), standard deviation (STD), skewness (SK), kurtosis (KUR), and current amplitude (CA), and three frequency-domain features, namely amplitude–frequency energy (AFE), amplitude–frequency mean (AFM), and amplitude–frequency kurtosis (AFK), are extracted. An improved principal component analysis (PCA)-based feature fusion method transforms the eight original time–frequency features into a five-dimensional PCA-fused feature representation consisting of PC1, PC2, PC3, fused PC4–PC7, and PC8. The fused features are classified using a radial basis function (RBF)-support vector machine (SVM) model. The proposed method achieves 98.68% test accuracy, 0.9869 Macro-F1, and 0.9931 Macro-AUC. A classifier comparison and feature-level latency analysis are also provided to clarify the accuracy–cost tradeoff and deployment feasibility. The results indicate that the proposed method can provide an interpretable and lightweight solution for electric bicycle controllers, battery management systems (BMSs), and onboard safety-monitoring applications. Full article

This paper presents proprietary, multi-platform software developed in Python for analyzing the electrical and microstructural properties of silicon solar cell metallization. Utilizing a sample set of 20 commercial solar cells, electrical resistivity and contact resistance measurements obtained via the potential difference method were correlated with high-resolution topographic data from AFM, SEM, and CLSM. This process enabled the quantification of how specific features, such as surface roughness and finger height, directly influence electrical performance. The developed algorithms offer high-fidelity predictive capabilities, with relative errors below 4%. This “virtual laboratory” serves as a transformative research and educational tool, allowing for complex materials analysis while avoiding the necessity for destructive testing. Full article

The growing demand for effective delivery of active ingredients in cosmetic formulations has stimulated the development of advanced carrier systems. This study evaluates the potential of the dicephalic di-N-oxide surfactant N,N-bis [3,3-(dimethylamino)-propyl]dodecylamide (C₁₂-(DAPANO)₂) as a stabilizer for aqueous dispersions of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). Lipid nanoparticles were prepared using three classes of solid lipids—cetyl palmitate, glyceryl behenate, and stearic acid—through high-speed homogenization followed by ultrasonication. Their physicochemical properties were characterized using DLS, TEM, AFM, DSC, and TGA. All formulations exhibited particle sizes below 300 nm and a low polydispersity index (<0.30), indicating good uniformity. High absolute zeta potential values and stability studies confirmed excellent physical stability, with all dispersions remaining stable for at least 90 days at room temperature. Compared with bulk lipids, nanoparticles showed lower melting temperatures and reduced crystallinity. NLCs exhibited lower crystallization and melting temperatures than SLNs and displayed a more spherical morphology. Cytotoxicity assessment using J774.E macrophages revealed no adverse effects. These findings highlight the surfactant’s potential as a stabilizing agent for lipid-based cosmetic nanocarriers, supporting the development of stable systems with improved active ingredient loading and controlled release properties. Full article

This study comparatively evaluated Raydent (here interpreted as a standard black chrome-type industrial condition in the present specimen context), DLC, and SiO₂ coatings for high-precision LM-guide applications as an application-oriented initial screening study. The emphasis was placed on dimensional preservation, surface integrity, and mechanical surface response rather than on complete coating-mechanism validation. Cross-sectional FE-SEM, EDS, Vickers hardness testing, surface profilometry, AFM, and SEM analyses were conducted to compare coating thickness, composite surface hardness, roughness, and morphology, and the influence of plasma pretreatment on the SiO₂ system was additionally investigated. Among the investigated coatings, SiO₂ exhibited the smallest thickness (1.03 μm), highest composite surface hardness (719.8 HV), and lowest average roughness (213.5 nm), suggesting favorable dimensional compatibility and surface integrity under the tested conditions. Plasma pretreatment increased the EDS-detected Si signal from 0.77 to 2.81 wt% and improved the composite surface hardness from 580 to 720 HV, suggesting an altered near-surface response and improvement in coating formation during pretreatment-assisted processing. AFM and SEM observations further indicated that the SiO₂ coating provided a more uniform and flatter surface morphology on the coupon specimens, whereas the DLC specimen prepared under the present commercial condition showed localized protrusions that may be associated with initial local contact disturbance. The comparative results suggest that SiO₂ coatings provide a favorable balance of thickness control, surface uniformity, composite surface hardness, and roughness for precision LM-guide applications. Although additional rolling-contact durability, adhesion, wear, friction-coefficient, and rolling-contact-fatigue studies are still required, the present findings should be interpreted as an initial screening result indicating that SiO₂ is a candidate coating condition for further engineering consideration in precision motion-guide systems, rather than as a direct validation of full tribological or long-term durability performance. Full article

A Negative Derivative Feedback (NDF) controller is designed for vibrations suppression of an atomic force microscope (AFM) model. The controlled system is modeled as a two-degree-of-freedom (2-DOF) closed-loop dynamic system. The average method was used to derive approximate analytical solutions. All possible resonance conditions were identified, with particular attention given to the simultaneous resonance case $\mathsf{\Omega }={\omega }_1, {\mathsf{\Omega }}_1={2\mathsf{\omega }}_1, {\mathsf{\omega }}_2={\mathsf{\omega }}_1$, identified as the most critical. For validation and proper insights, the system was also solved numerically using the fourth-order Rung–Kutta method. The time response of the AFM system in contact mode was analyzed before and after applying the NDF controller under the worst-case resonance conditions. A comprehensive parametric study was conducted to evaluate the controller’s robustness and effectiveness. The results demonstrate a high degree of agreement between the numerical simulations and the analytical approximations, confirming the reliability of the approach. Full article

This study investigates color and surface alterations in neat and modified PEEK materials (10 × 3 mm, n = 140) immersed in various beverage solutions. Surface roughness (Ra) and color change (ΔE) were analyzed, supported by SEM and AFM evaluations. Specimens polished with 400–1200 grit sandpaper were measured via profilometry before a 30-day immersion in distilled water, coffee, tea, cola, and red wine (refreshed every 12 h). Post-immersion results indicated that material and solution types significantly influenced Ra and ΔE values (p < 0.05), with the TP group being the least affected. Statistically, tea caused the greatest discoloration. The GFP group exhibited the highest Ra, indicating inferior surface stability, whereas TP and CR groups remained below the 0.2 μm clinical threshold. Specifically, the TP group demonstrated the lowest Ra value. Although perceptible color changes occurred in all materials, a positive correlation was identified between material type and beverage solutions. SEM and AFM analyses confirmed the presence of surface micro-cracks and morphological irregularities. Full article

Hard chromium coatings are widely used for their excellent wear and corrosion resistance, but replacing conventional hexavalent chromium with safer trivalent chromium processes remains limited by adhesion-related issues. This study proposes a simple, quantitative method for evaluating the adhesion of hard chromium coatings deposited on ductile steel substrates using an instrumented uniaxial tensile test. Adhesion is defined as the substrate strain at the onset of coating cracking or delamination, while damage evolution is monitored in situ using optical imaging. Trivalent chromium coatings, produced using four different surface preparation routes, were investigated and compared with conventional hexavalent chromium coatings used as references. Fractographic SEM/EDS analyses were performed to identify cohesive and adhesive failure modes. In parallel, the substrate surface energy prior to coating deposition was assessed using atomic force microscopy via pull-off force measurements. The tensile test successfully differentiated the adhesion performance associated with the different surface preparations. A strong correlation was observed between the critical strain measured during tensile testing and the AFM-derived pull-off forces, highlighting the major influence of substrate pretreatment on coating adhesion. The proposed methodology provides a practical tool for the qualification and optimization of hard chromium coating processes. Full article

Cardiorenal Syndrome (CRS) types depend on the primary impaired organ, Heart (Types I/II) or Kidney (Types III/IV), and are chronic (Types II/IV) or acute (Types I/III). Type V associates to a systemic disease. Diagnosis of CRS type via biochemical indices (e.g., B-type-natriuretic-peptide (BNP), neutrophil-gelatinase-associated-lipocalin (NGAL)) has not been documented absolutely, until now. Here we used advanced imaging facilities, atomic force microscope (AFM) and scanning electron microscope (SEM) for the biopsy of peripheral blood smears coming from CRS patients, aiming to investigate the possible existence of cellular indices associated with CRS pathology. Standard biochemical and hematological indices were comparatively recorded. Cylindrical micro/nano-metric Vesicles (mnVs) were observed in all CRS patients. In CRS patients with Types III/IV, the AFM/SEM data revealed an increased mnVs population and activated platelets that may represent their potential parent cells. In these patients, increased basic uraemic indices and BNP and NGAL levels were also observed. On the contrary, in patients with CRS Types I/II/V, the AFM/SEM data showed a comparatively smaller mnVs population, accompanied by lower levels of BNP and NGAL. According to our results, a higher mnVs population was observed in CRS Types III/IV, possibly released from platelets. The mnVs population may be associated with basic uraemic indices and increased BNP and NGAL levels. Full article

This study aimed to evaluate the surface changes depicted on Reciproc and Reciproc Blue R25 files after their immersion in different irrigants at different temperatures compared to the non-immersed controls, utilizing Atomic Force Microscopy (AFM). To measure the Root Mean Square (RMS) and Mean Roughness (Sa), eight R25 files (four/system) were divided into four groups (n = 2; one file/system): non-immersed (control), immersed in 17% ethylenediaminetetraacetic acid (EDTA) set at 37 °C, and immersed in 5.25% sodium hypochlorite (NaOCl) set at 37 °C or at 45 °C. Immersion time was 10 min after which AFM was conducted. There was no significant difference in mean RMS and Sa between the control and the 17% EDTA group (p > 0.05). Immersion in 5.25% NaOCl at 37 °C significantly increased surface irregularities on both files (p < 0.05). This increase was further accentuated by NaOCl’s temperature rise to 45 °C (p < 0.05). Reciproc exhibited significantly higher surface roughness compared to Reciproc Blue under all conditions (p < 0.05). Immersion in 5.25% NaOCl altered the surface topography of Reciproc and Reciproc Blue which was further accentuated by its temperature rise, while immersion in 17% EDTA had no significant effect on their surface changes. Reciproc demonstrated significantly higher surface roughness compared to Reciproc Blue under all tested conditions. Full article

To address the uneven deposition of zirconium conversion coatings on multiphase 55AlZnMg under short pretreatment cycles, this study investigated the time-dependent formation behavior of ZrCC in a selected H₂ZrF₆ bath. By precisely controlling the immersion time (20–90 s) and utilizing SEM-EDS and AFM characterization techniques, this study systematically revealed the growth kinetics and film-forming mechanisms of ZrCC on complex alloy surfaces. The results indicate that the Zn-rich phase on the surface of the 55AlZnMg coating, due to its relatively positive potential, preferentially induces the deposition of the film-forming material. Subsequently, dealloying occurs in the Al-rich phase and the Mg/Zn enriched regions, forming Zn-enriched regions that promote the continuous deposition of the film-forming material, ultimately achieving complete surface coverage; the film morphology evolves from an initial needle-like structure to a network structure, eventually forming a nanosheet structure. The film-forming process of ZrCC on the 55AlZnMg substrate surface is primarily driven by selective growth, with electrochemical properties of the alloy phases, significantly enhancing adhesion between the aluminum-zinc-magnesium coating and the overcoat and providing practical guidance for improving surface uniformity and interfacial adhesion of Al-Zn-Mg-coated steel. Full article

In this study, the rapidly setting and hardening high-belite sulfoaluminate cement (HBSAC) is used as the cementitious material, with natural river sand as the fine aggregate, and a high-performance repair mortar is prepared through the synergistic use of different polymers and admixtures. The influences of two polymers (VAE and HPMC) on the working performance, mechanical properties, and hydration characteristics of HBSAC mortars are systematically studied. The results showed that the two polymers had a significant improvement effect on the setting time, mortar flowability, and water retention rate of HBSAC mortar. Among them, VAE had a significant effect on the mortar flowability, and a 5% content could increase the flowability of HBSAC mortar by 29.8%. HPMC has a significant improvement effect on setting time and water retention rate; at 0.1% content, it can delay the initial setting time by 6.5 min and achieve a water retention rate of over 90%. As the polymer to binder ratio increases, both polymers, except for 2.5% VAE, which can slightly improve the flexural strength of mortar, will reduce the flexural and compressive strength of mortar, with VAE causing greater damage to strength. On the contrary, the polymer significantly enhanced the bond strength of the mortar. Compared with the cement control group, the 28 d bond strength of 5% VAE and 0.1% HPMC groups increased by 56.7% and 15.1%, respectively. Moreover, the addition of polymers delayed the occurrence of the exothermic peaks of HBSAC dissolution and ettringite formation, but the total amount of hydration heat released within 48 h was higher than that of pure cement. The diffraction peaks of AFt in the hydration products of VAE-HBSAC paste at 3d and 28d showed significant enhancement, and the peak intensity increased with higher doping levels, while the diffraction peak intensity of C₂S showed a certain decrease. The polymer significantly increased the weight loss peak intensity and mass loss after heating of AFt, AH₃, AFm, and C-S-H gel. The SEM images indicate that VAE can form a mesh on the surface of hydration products and refine the crystal size of AFt; HPMC wraps more flocculent substances around the hydration products, thereby improving the compactness of paste. This study can provide scientific reference for improving the performance and promoting the practical application of high-performance rapid repair mortar for concrete structure damage. Full article

Background/Objectives: Lipid-based nanocarriers have emerged as promising systems for improving the delivery of poorly soluble drugs by enhancing stability, bioavailability, and controlled release. This work aimed to formulate solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) containing ciprofloxacin (CIP) using solvent-free procedures. Methods: The systems were extensively characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) to study the nanoparticles in the solid state. Furthermore, in vitro drug release was evaluated, and mathematical modeling was applied to analyze the resulting release kinetics. Additionally, storage stability was assessed at 4 °C and 25 °C over a period of 8 months. Results: The results indicated that SLN with an average size of ~50 nm (SLN 50) and NLC with mean diameters of ~25, 50, and 100 nm (NLC 25, NLC 50 and NLC 100 respectively) were successfully prepared. DLS measurements showed narrow particle size distributions (PdI ≤ 0.2) and negative zeta potentials ranging from −3.7 to −7.7 mV. Encapsulation efficiencies were remarkably high for most systems, reaching ~98% for SLN 50, NLC 50, and NLC 100, while the smallest formulation (NLC 25) showed a lower efficiency (~80%). Both TEM and AFM confirmed the formation of spherical nanoscale structures consistent with the sizes determined by DLS. Release studies revealed a strong influence of particle size on kinetics: NLC 25 exhibited rapid release (~95% within 30 min), whereas NLC 100 showed a sustained profile (<20% after 6 h). Dissolution profiles were accurately described by the Lumped-Gonzo kinetic model (R² > 0.98), enabling estimation of dissolution efficiency. Conclusions: These findings confirm that lipid-based nanocarriers can be engineered to precisely control CIP release. Full article

The growing request for more sustainable materials and environmentally friendly nanofabrication methods in the electronics field has recently driven the scientific community in the development of bio-derived materials as an alternative to conventional lithographic resists. In this work, we used chitosan, a biodegradable and biocompatible polysaccharide, as a green direct-write resist material for Atomic Force Microscopy-based nanolithography. Chitosan thin layers were obtained by spin coating and systematically characterized, in terms of thickness and surface roughness, demonstrating nanoscale smoothness and tunable film thickness. Three Pulse–Atomic Force Lithography (P-AFL) approaches, i.e., Constant Pulse, Gradient Pulse, and Raster Pulse AFL methods, were used to pattern nanostructures with constant-depth nanogrooves, variable-depth (2.5D) profile, and three-dimensional nanoholes on chitosan films. The results reveal high pattern fidelity, reproducibility, and tunability of feature dimensions as a function of applied force and scanning direction. Moreover, the RP-AFL technique enabled the fabrication of well-defined 3D nanostructures with depths matching the film thickness, which is a prerequisite for subsequent pattern transfer. This experimental work provided a first proof-of-concept to adopt chitosan as a more sustainable alternative with respect to conventional resists. Moreover, the results highlight P-AFL methods as a versatile and low-impact nanofabrication strategy, contributing to the development of greener micro- and nano-manufacturing technologies. Full article

Aflatoxin M1 (AFM1) is a Group 1 human carcinogen that poses a public health risk through milk contamination. This study investigated AFM1 contamination in pasteurized and ultra-high temperature (UHT) milk from south–central and northwest China, and assessed the associated health risks for consumers based on age, sex, and milk consumption scenarios. In total, 902 milk samples (493 pasteurized, 409 UHT) were collected during the summer and winter seasons of 2023–2024. AFM1 levels were determined using a validated enzyme-linked immunosorbent assay. AFM1 was detected in 75.39% of samples (mean concentration, 12.35 ± 10.27 ng/L; maximum, 75.57 ng/L). While 1.55% of samples exceeded the EU maximum limit (50 ng/L), all complied with the Chinese limit (500 ng/L). Contamination was significantly higher in south–central China than northwest China, higher in winter than summer, and higher in pasteurized milk than UHT milk (p < 0.05). Preschool children in south–central China consuming 400 mL/day of milk are the group with the highest AFM11 exposure risk. And the margin of exposure and population risk of liver cancer suggested little carcinogenic risk. Therefore, targeted monitoring strategies for AFM1 in milk are recommended, along with dietary guidance for high-risk groups, especially vulnerable young children, to mitigate exposure. Full article

This study investigates the macro- and micromechanical properties of epoxy-based nanocomposites containing Mg-Al/NO₃ layered double hydroxides (LDHs), with a comparative evaluation of two preparation routes: solvent exchange and direct drying from an aqueous LDH slurry. LDHs were characterised using atomic force microscopy (AFM), scanning transmission electron microscopy, and X-ray diffraction methods. Tensile tests and AFM nanomechanical mapping were used to obtain the macro- and micromechanical properties of LDH/epoxy nanocomposites, respectively. Both preparation methods resulted in nanocomposites with comparable mechanical performance. Young’s modulus increased by approximately 30–70% at lower LDH loadings (1–2 wt.%), and the ultimate tensile strength remained largely unchanged compared to pure epoxy. At higher LDH contents, tensile strength decreased by approximately 15–26%, while fracture strain decreased by up to 54%, which was attributed to particle aggregation, as confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mechanical response and stiffness maps obtained by the peak force AFM nanomechanical mapping revealed that nanocomposites prepared using solvent-exchanged LDHs exhibit significantly narrower interfacial widths and higher stiffness compared to those made by the conventional approach, indicating improved interfacial bonding and mechanical performance. Overall, the solvent-exchange approach proved effective for improving the interfacial properties and stiffness of epoxy/LDH nanocomposites. Full article