Search Results (3,804)

Double-shell ZnO/Al₂O₃ submicron hollow fibers were successfully fabricated through a combined electrospinning and atomic layer deposition (ALD) approach. Polyvinyl alcohol (PVA) fibers were first produced by electrospinning and subsequently coated with a conformal Al₂O₃ barrier layer via low-temperature ALD employing trimethylaluminum (TMA) and deionized (DI) H₂O to preserve the integrity of the temperature-sensitive polymer core. The inner polymer was then removed using two different techniques—thermal annealing and water dissolution—to compare their effects on the fiber morphology. Finally, a functional ZnO layer was deposited by thermal ALD with diethylzinc (DEZ) and DI H₂O. It was found that the polymer removal method critically determined the final structural and morphological characteristics of the fibers. Thermal annealing resulted in smooth, shrunken fibers, while water dissolution led to diameter expansion and the formation of a highly rough, bubble-like surface structure due to swelling-induced micro-cracking. The selection of the polymer removal method offers a precise and controllable route for tailoring the fiber morphology. The resulting high-aspect-ratio (HAR) structures, particularly the rough and expanded fibers, exhibit enhanced specific surface area, making them highly promising for applications in sensing, catalysis, and filtration. Full article

The effect of CO₂ laser treatment on the surface composition and properties of a woven fabric (polyester (PET) fiber (59 wt%)/cotton (CO) fiber (31 wt%)/stainless-steel (SS) metal fibers (10 wt%)) was investigated across a range of laser intensities (19.1 × 10⁶ to 615.0 × 10⁶ W/m²). Elemental analysis using wavelength-dispersive X-ray fluorescence (WD-XRF) revealed that for an intensity up to 225.4 × 10⁶ W/m², the carbon content on the fabric surface increased while the oxygen content decreased, indicating thermally induced surface modification. Fourier transform infrared (FT-IR) spectroscopy confirmed that no new chemical bonds were formed, suggesting that the changes observed were predominantly physical in nature. High-resolution scanning electron microscopy (HR-SEM) showed progressive fiber fusion and surface smoothing with increasing laser intensity, consistent with polyester melting. Tensile testing demonstrated a significant decline in peak load and elongation at peak load with rising laser fluence, indicating mechanical embrittlement. Overall, CO₂ laser treatment alters the morphology and elemental composition of the fabric surface without inducing major chemical decomposition, markedly reducing its mechanical strength. Full article

Traditional CGH algorithms often face a trade-off between computational efficiency and reconstruction fidelity. In this study, we propose a hybrid hologram synthesis framework that combines geometric and physical optics to generate phase-only holograms for SLM. A freeform surface obtained from geometric optics provides a smooth continuous phase initialization for the iterative CGH solver, which substantially reduces the number of required iterations. We further improve the SGD-based optimization by introducing an adaptive step size factor and explicit phase constraints during the update process. These modifications guide the solution toward a smooth phase profile, thereby suppressing high-frequency phase noise and mitigating speckle artifacts. Compared with a standard CGH algorithm, the proposed method achieves an approximately four times improvement in computational efficiency while maintaining reconstruction quality. Finally, we integrate the resulting holograms into an eye tracker–based autofocus system, enabling real-time adaptation to changes in the human eye’s focal state. Full article

Mobile robots conducting inspection tasks in coal-mine roadways and operating in complex underground environments are often subjected to demanding conditions such as low adhesion, uneven friction distribution, and localized slippery surfaces. These challenges are significant, predisposing the robots to trajectory deviation and posture instability, thereby presenting substantial obstacles to high-precision tracking control. The primary innovation of this study lies in proposing a hierarchical model predictive control (HMPC) strategy, which addresses the challenges through synergistic, kinematic and dynamic optimization. The core contribution is the construction of dual-layer optimization architecture. The upper-layer kinematic MPC generates the desired linear and angular velocities as reference commands. The lower-layer MPC is designed based on a dynamic model that incorporates ground adhesion characteristics, enabling the online computation of optimal driving forces (F_L, F_R) for the left and right tracks that simultaneously satisfy tracking performance requirements and practical actuation constraints. Simulation results demonstrate that the proposed hierarchical framework significantly outperforms conventional kinematic MPC in terms of steady-state accuracy, response speed, and trajectory smoothness. Experimental validation further confirms that, in environments with low adhesion and localized slippery conditions representative of actual roadways, the proposed method effectively coordinates geometric accuracy with dynamic feasibility. It not only markedly reduces longitudinal and lateral tracking errors but also ensures excellent dynamic stability and reasonable driving force distribution, providing key technical support for reliable operation in complex underground environments. Full article

Lentinula edodes (shiitake) is a major edible and medicinal mushroom and a key component of the horticultural mushroom industry in East Asia. During April–June 2024 cropping season, a widespread blue mold outbreak was observed on bag-cultivated shiitake in Xixia County, Henan Province, China. Affected cultivation rooms showed extensive blue-green sporulation on the exposed surfaces of substrate blocks and on developing and mature fruiting bodies, leading to rapid loss of marketability. To clarify the etiology of this disease, we coupled field surveys with morphological, molecular, and pathogenicity analyses. Fifty-five Penicillium isolates were obtained from symptomatic cultivation bags. Three representative isolates (LE06, LE15, and LE26) were characterized in detail. Colonies on PDA produced velutinous to floccose mycelia with blue-green conidial masses and terverticillate penicilli bearing smooth-walled, globose conidia. Sequencing of four loci—the internal transcribed spacer (ITS1-5.8S-ITS2), β-tubulin (benA), calmodulin gene (CaM), and RNA polymerase II second largest subunit (rpb2)—followed by multilocus phylogenetic analysis placed all three isolates in a well-supported clade with the ex-type CBS 227.28 of Penicillium bialowiezense. Inoculation of healthy shiitake cultivation bags with conidial suspensions (1 × 10⁶ conidia mL⁻¹) reproduced typical blue mold symptoms on substrate surfaces and fruiting bodies within 40 days post inoculation, whereas mock-inoculated controls remained symptomless. The pathogen was consistently reisolated from diseased tissues and showed identical ITS and benA sequences to the inoculated strains, thereby fulfilling Koch’s postulates. This is the first confirmed report of P. bialowiezense causing blue mold on shiitake, and it expands the known host range of this species. Our findings highlight the vulnerability of bag cultivation systems to airborne Penicillium contaminants and underscore the need for improved hygiene, environmental management, and targeted diagnostics in commercial shiitake production. Full article

This paper introduces a biological surface that is resistant to erosion under liquid–solid two-phase flow. Numerical simulations are used to study the erosion of smooth and ribbed shells by particles. The results show that when the flow direction is perpendicular to the direction of the shell ribs, the total erosion rate of the ribbed shell is 29.08% lower than that of the smooth shell, and the impact velocity of particles with a diameter of 0.5 mm on the ribbed shell is 15.91% lower than that on the smooth shell. This phenomenon occurs because a low-velocity flow field is formed in the grooves of the ribbed shell, which causes the particles to decelerate for some time before impacting the shell. This ribbed structure may provide design ideas for equipment that is susceptible to erosion. Full article

The advancement of reactive powder concrete (RPC) technology primarily focuses on modifications to its conventional composition. This involves substituting Portland cement (CEM I) with alternative cement types and finely ground mineral additives, as well as replacing quartz aggregate with another type of aggregate. The paper presents an analysis of the properties of RPC obtaining using waste sand and powder generated during the processing of aggregates from migmatite-amphibolite rock. Research into RPC mixtures revealed that in one scenario, replacing quartz powder with waste powder resulted in a significant increase in flexural strength by 23%, although there was a slight decrease in compressive strength by 7%. However, when both quartz powder and quartz sand were substituted with waste powder and waste sand, there was a 14% reduction in compressive strength, while flexural strength increased, albeit to a much lesser extent. The analysis of mineral composition and microstructure of migmatite-amphibolite waste powder and sand revealed that the primary factor contributing to the increase in flexural strength is the presence of biotite in a flake shape form. The microscopy images clearly show hydration products gathering mainly at the rims of biotite flakes and not on their smooth surfaces. The reason could be better availability for hydration products attachment and lower steric hindrance to the rims of single biotite flakes instead of its large packets. Conversely, the reduction in RPC compressive strength, resulting from the substitution of quartz sand with migmatite-amphibolite waste sand, can be attributed mainly to the lower compressive strength of the waste sand itself. Test results indicate that the waste powder generated during the production of migmatite-amphibolite aggregates, which contains fine flakes of biotite, can be utilised as a mineral admixture in concrete, thereby enhancing its flexural strength. Full article

Peri-implant infections pose a significant challenge in dental implantology. This study aimed to develop and characterize a chitosan–vancomycin coating for titanium surfaces, focusing on drug loading, release kinetics, antimicrobial performance, and cytocompatibility. Grade 4 titanium discs were coated with a chitosan film using the dip-coating technique and subsequently loaded with vancomycin through immersion in an aqueous solution. Coating morphology was examined by scanning electron microscopy (SEM). Vancomycin loading was quantified by spectrophotometry, and release kinetics were monitored over 144 h (6-day). Antimicrobial activity was assessed through agar diffusion assays against Staphylococcus aureus. Cytocompatibility was evaluated using human mesenchymal stem cells (hMSCs), whose metabolic activity, adhesion, and morphology were assessed over a 19-day culture period by resazurin assay and SEM. SEM analysis revealed a uniformly distributed, smooth, and crack-free chitosan film, which remained stable after drug loading. The coating exhibited a biphasic release profile, characterized by an initial burst followed by sustained release over six days, which maintained antimicrobial activity, as confirmed by inhibition zones. hMSCs adhered and proliferated on the coated surfaces, displaying normal morphology despite a transient reduction in metabolic activity on vancomycin-containing films. These findings support the potential of chitosan–vancomycin coatings as localized antimicrobial strategies for implant applications, warranting further in vivo and mechanical evaluations. Full article

To enhance the overall quality and consistency of depth maps, Digital Surface Models (DSM), and True Digital Orthophoto Map (TDOM) in UAV image reconstruction, this paper proposes a multi-stage adaptive optimization generation method. First, to address the noise and outlier issues in depth maps, an adaptive joint bilateral filtering-based optimization method is introduced. This method repairs anomalous depth values using a four-directional filling strategy, incorporates image-guided joint bilateral filtering to enhance edge structure representation, effectively improving the accuracy and continuity of the depth map. Next, during the DSM generation stage, a method based on depth value voting space and elevation anomaly detection is proposed. A joint mechanism of elevation calculation and anomaly point detection is used to suppress noise and errors, while a height value completion strategy significantly enhances the geometric accuracy and integrity of the DSM. Finally, in the TDOM generation process, occlusion detection and gap-line generation techniques are introduced. Together with uniform lighting, color adjustment, and image gap optimization strategies, this improves texture stitching continuity and brightness consistency, effectively reducing artifacts caused by gaps, blurriness, and lighting differences. Experimental results show that the proposed method significantly improves depth map smoothness, DSM geometric accuracy, and TDOM visual consistency compared to traditional methods, providing a complete and efficient technical pathway for high-quality surface reconstruction. Full article

Adhesive joint failure remains a critical limitation in the manufacturing of large wind turbine blades, where reliable and reproducible surface preparation methods are required at an industrial scale. This study systematically evaluates the effect of peel ply-induced surface morphology and chemistry on the adhesion performance of glass fiber-reinforced polymer (GFRP) laminates, explicitly examining the relationship between wettability and bonding strength. Five surface conditions were generated during vacuum-assisted resin infusion using different commercial and proprietary peel plies and a smooth mold surface. Despite significant differences in contact angle and surface energy, lap shear testing revealed no significant relationship between wettability and joint strength. Instead, surface roughness-driven mechanical interlocking and adhesive–substrate compatibility dominated performance. Compared to the smooth mold surface, twill-type peel ply–modified adherends increased shear strength by up to 3.9×, while other commercial types of peel-plies presented strength improvements between 2.7 and 3.3×. More compatible adhesive–polymer resin systems exhibited a combination of cohesive and adhesive failures, with no clear dependence on surface roughness. In contrast, when the adhesive is less compatible with the substrate, surface roughness significantly affects the adhesive response, with adhesive failure predominating. The adhesive application temperature showed no measurable effect for practical industrial use. These findings demonstrate that wettability alone is not a reliable predictor of adhesion performance for this class of substrates and confirm peel ply surface modification as a robust, scalable solution for industrial wind blade bonding. Full article

The incrustation process represents a significant industrial challenge that affects various aspects of crystallization systems. It proceeds through successive stages, beginning with the induction period. This is followed by a transport phase, in which additional crystals are generated and sustained by overall supersaturation and the presence of seed crystals, leading to further attachment to surfaces. Ultimately, the process progresses to crystal removal and aging stages. In this study, a 1.2 dm³ thermostated crystallizer was utilized to investigate the incrustation phenomenon of potassium nitrate (KNO₃). Deposits formed on three smooth and artificially roughened wall-surfaces, i.e., stainless steel (Type 316), copper, and acrylic, were examined. Contact angle measurements were conducted for all surfaces. The experiments covered a saturation temperature range of 303.15–333.15 K (±0.01 K) for various KNO₃ solution concentrations between 5.0 and 60.0% w/w. The results show that deposit adhesion is stronger on rough surfaces than on smooth ones, and that the induction period for incrustation is shorter on rougher surfaces. Moreover, the influence of surface wettability and contact angle on incrustation becomes more pronounced at higher degrees of surface roughness. This highlights the coupled role of surface properties and thermal control in governing incrustation behavior. Full article

This paper presents an experimental study on the influence of surface texturing on friction and film thickness in the hydrodynamic lubrication regime. Using a pin-on-disk tribometer equipped with light-induced fluorescence microscopy, simultaneous measurements were conducted on smooth and textured samples under parallel and inclined surface conditions. The circular faces of the pins were partially or fully covered by circular laser-machined textures consisting of dimples with depths of 5 or 10 µm, diameters of 50 or 100 µm, and coverage density of 20%. The results demonstrate that while texturing significantly reduces friction and increases film thickness in parallel gaps, with partial inlet coverage being the most effective, its impact is minimal in inclined wedge gaps. The study further reveals that the global geometric wedge dominates over texture effects in inclined contacts and that in-texture cavitation, prevalent in parallel conditions, is suppressed by surface inclination. Three distinct contributions of the textures were discussed: a global hydrodynamic effect, a local hydrodynamic effect, and the influence of surface non-flatness (waviness). The findings suggest that texturing is primarily beneficial for acting as a pseudo-wedge or as surface roughness in contacts where a physical wedge is absent. Full article

The growing need for self-powered Internet of Things networks has raised interest in converting abundant waste into reliable energy harvesters despite long-standing material and technology challenges. As demand for environmentally friendly self-powered IoT devices continues to rise, attention toward green waste as an eco-friendly energy source has strengthened. However, its direct utilisation in high-performance energy harvesters remains a significant challenge. Driven by the growing need for renewable sources, the triboelectric nanogenerator has emerged as an innovative technology for converting mechanical energy into electricity. In this work, the design, fabrication, and characterisation of a rotating triboelectric energy harvester as a prototype device employing date seed waste as the tribopositive layer are presented. The date seeds particles, measuring 1.2 to 2 mm, were pulverised using a grinder, mixed with epoxy resin, and subsequently applied to the grating-disc structure. The coated surface was machined on a lathe to provide a smooth surface facing. The performance of the prototype was evaluated through a series of experiments to examine the effects of rotational speed, the number of grating-disc structures, the epoxy mixing process, and the prototype’s influence on the primary system, as well as to determine the optimal power output. An increase in rotational speed (RPM) enhanced power generation. Furthermore, increasing the number of gratings and pre-mixing of epoxy with the biomaterial resulted in enhanced output power. Additionally, with 10 gratings, operating at 1500 rpm, and a 24 h pre-mixing method, the harvester achieved maximum voltage and power outputs of 129 volts and 1183 μW at 7 MΩ. Full article

The selection of data smoothing methods is one of the key steps in extracting land surface phenology parameters from time-series remote sensing data. However, existing studies often use default parameters for denoising the time-series data, neglecting the sensitivity of phenology extraction to different combinations of smoothing parameters. Therefore, this study systematically evaluated three parametric smoothing methods—Savitzky–Golay (SG), Whittaker Smoother (WS), and Harmonic Analysis of Time-Series (HANTS)—and two non-parametric methods—Asymmetric Gaussian (AG) and Double-Logistic (DL)—on the accuracy of Start of Season (SOS) and End of Season (EOS) extraction at eight ground phenology observation sites in Inner Mongolia, based on time-series MOD13Q1- Normalized Difference Vegetation Index data and using the derivative method as the background for phenology parameter extraction at the site scale. The results showed that (1) DL and HANTS yielded similar accuracy for phenology extraction in desert steppe, while parametric smoothing methods outperformed non-parametric methods in phenology simulation in typical and meadow steppe regions. (2) We proposed the optimal phenology parameter combination for different steppe types in Inner Mongolia. For desert steppe, DL or HANTS was recommended. For SOS extraction in typical steppe ecosystems, the WS parameter combination was used. For EOS and phenology in meadow steppe, the HANTS parameter combination yielded better simulation results. (3) In desert and meadow steppes, the window radius in SG contributed more to phenology accuracy than polynomial order. The opposite was true for typical steppe. In WS, the contribution of the differential order to SOS and EOS extraction in desert and typical steppes was higher than that of the smoothing factor. The opposite was observed in meadow steppe. In HANTS, the fitting tolerance error was the key factor controlling phenology extraction accuracy. (4) Based on the optimal phenology extraction scheme, the smallest extraction error occurred in meadow steppe at the site scale. This was followed by typical steppe. Desert steppe showed relatively larger errors. This study overcomes the reliance on default parameters in previous studies and proposes a practical framework for phenology extraction for different grassland ecosystems. The findings provide new empirical evidence for method selection and parameter setting in remote sensing phenology monitoring. Full article

Background/Objectives: Formation of tight contacts between oral soft tissue and dental implants is a significant challenge in contemporary implantology. An essential role in this process is played by oral epithelial cells. In the present study, we investigated how titanium and zirconia surfaces with different roughness influence various parameters of oral epithelial cells in vitro. Methods: We used the human oral squamous carcinoma Ca9-22 cell line and cultured them on the following surfaces: machined smooth titanium (TiM) and zirconia (ZrM) surfaces, as well as sandblasted and acid-etched titanium moderately rough (SLA) and zirconia (ZLA) surfaces. Cell proliferation/viability was measured by CCK-8 assay, and cell morphology was analyzed by fluorescent microscopy. The gene expression of interleukin (IL)-8, intercellular adhesion molecule (ICAM)-1, E-cadherin, integrin (ITG)-α6, and ITG-β4 was measured by qPCR, and the content of IL-8 in conditioned media by ELISA. Results: At the initial culture phase, cell proliferation was promoted by rougher surfaces. Differences in cell attachment were observed between machined and moderately rough surfaces. Machined surfaces were associated with slightly higher IL-8 levels (p < 0.05). Furthermore, both ZLA and SLA surfaces promoted the expression of (ITG)-α, ITG-β4, and ICAM-1 in Ca9-22 cells (p < 0.05). Surface material had no impact on the investigated parameters. Conclusions: Under the limitations of this in vitro study, some properties of oral epithelial cells, particularly the immunological and barrier function, are moderately modified by roughness but not by material. Hence, the roughness of the implant surface might play a role in the quality of the peri-implant epithelium. Full article