Search Results (16)

This study addresses the challenges posed by weakly cemented strata in mine tunnels, where surrounding rock softens and deforms upon water exposure, which promotes the development of seepage pathways, and exhibits insufficient stability in bolt (cable) support systems. This study conducts laboratory grouting tests using silica sol on typical weakly cemented sandstone from Xinjiang mining areas. The mineral composition and pore structure were characterized using XRD, SEM, and mercury porosimetry. The injectable mixing ratio parameters for silica sol and the catalyst were determined through viscosity-time evolution tests. Grouting was performed using a custom-built constant-pressure grouting apparatus. After curing, unconfined compressive strength (UCS) and porosity-permeability tests were conducted to evaluate the micro-mechanism of grouting effects on the mechanical and permeability properties of weakly cemented sandstone. The results indicate: (1) The sandstone exhibits a high clay mineral content of 39.8%, dominated by illite. Its pores are primarily small-scale (10–100 nm), accounting for 79.31% of the total pore volume. This scale matches that of silica sol nanoparticles (approximately 9–20 nm), facilitating slurry penetration into micro-pores; (2) microscopic analyses reveal that silica sol effectively reconstructs pore structures through permeation filling and surface coating. Compared to KCl-induced gelation (with approximately 8% gel coverage), NaCl-induced gelation forms a more continuous gel film with more complete pore filling, achieving coverage of around 22%. Furthermore, the larger surface area of the gel aggregates indicates a more thorough filling of micro- and nano-pores, effectively enhancing rock mass compactness. (3) Permeability decreased from 6.91 mD to 3.55 mD, a reduction of 48.6%, while porosity decreased from 16.94% to 13.55%, showing a phased reduction during the grouting process; (4) following pressure grouting stabilization, the uniaxial compressive strength of sandstone increased appropriately by approximately 7–14%, while the elastic modulus rose by about 18–28%. The failure mechanism shifted from shear brittleness to a shear-tension composite state, with enhanced post-peak bearing capacity. These findings provide support for optimizing silica sol grouting parameters in weakly cemented strata tunnels and for the synergistic reinforcement of rock mass permeability and strength. Full article

This study addresses the challenges of large-scale processing and resource utilization of mango waste in the Panzhihua region. Its focus is on investigating the key role of material ratio optimization in improving the humification quality of compost products. Three typical wet weight ratios of discarded mango and pruning branches were used (T1, T2, T3) toconduct high-temperature aerobic composting experiments under the stable environmental conditions provided by nanomembrane coverage. The temperature of the compost pile, nitrogen transformation, and dynamic changes in humic components were systematically monitored. The results showed that the T2 treatment achieved the optimal compost performance, entering the high-temperature period (≥55 °C) within 4 days, with a peak temperature of 61.9 °C, and the high temperature lasting for 13 days. The carbon-nitrogen ratio decreased by 46.6%, and the ammonia volatilization rate was the lowest (0.0135 mg/(m²·d)); the degree of humification was the highest, with the HA/FA ratio reaching 2.19 and the seed germination index being 222.49%. This study demonstrates that an appropriate “fruit-to-branch” ratio, under the stable environment created by nanomembrane coverage, can synergistically promote the compost humification process and product quality. This provides a reliable theoretical basis and technical pathway for the resource utilization of mango waste. Full article

Metal–Organic Frameworks (MOFs) have diverse applications due to their tunable porosity, large surface area, and diverse chemical functionalities. Among them, one of the most researched MOFs is MIL-101(Cr), which, in addition, is very stable in water. We have used a commercially available substance with approximately 300 nm large crystals for the preparation of a sensing nano-thin layer for the emerging water contaminant PFOS, due to its high selectivity towards this compound. Here, we have synthesized 20 nm sized crystals of MIL-101(Cr), which are among the smallest reported, and compared them to the same material with 300 nm sized crystals. The material was characterized by TEM and XPS. It was possible to prepare insoluble monolayers at the air–water interface (Langmuir films), which were characterized with film compression isotherms, Brewster angle microscopy, and surface potential measurements. The Langmuir–Blodgett (LB) method was used to deposit monolayers on Si wafers and 434 MHz Surface Acoustic Wave resonator simultaneously. The LB layers were very stable over time. The smaller-sized MIL-101 (Cr) crystals exhibit denser, more homogeneous water coverage and packing upon compression, with no observable 10–100 µm aggregates. LB monolayers from the 20 nm particles have approximately six times lower surface roughness. The LB monolayer is far from being smooth, but this will allow excellent access to the MOF pores by the tested analyte in a chemical sensing application. The lack of research on depositing presynthesized MOFs using probably the best method for nanoarchitectonics—the LB method—is addressed. The 20 nm sized MOF crystals are the smallest deposited by this method so far. Full article

The influence of electron beam melting (EBM) scan speed on the corrosion, nano-biotribological, and cellular adhesion properties of Ti-6Al-4V-ELI (extra low interstitials) was systematically investigated. Specimens were fabricated using five different scanning speeds, and tribological performance was assessed via reciprocating dry wear tests, while corrosion behaviour was evaluated through monitoring the open circuit potential and anodic potentiodynamic polarization tests in Ringer’s solution. Human fibroblasts from the FN1 cell line were used to assess cell adhesion. Specimens produced using scanning speeds of 4530 mm·s⁻¹ and 4983 mm·s⁻¹ exhibited increased passive current densities, indicating reduced corrosion protection, although all surfaces maintained the passive film characteristic. Tribological behaviour was strongly dependent on scan speed, with wear rate and penetration depth increasing at higher speeds; notably, an intermediate scan speed produced a surface with minimal wear and penetration depth despite a wide wear track, suggesting enhanced resistance to tribological degradation. Fibroblast cultures demonstrated robust adhesion and spindle-shaped morphology across all samples, with the disk produced using a scanning speed of 4983 mm·s⁻¹ showing the highest surface coverage, highlighting the role of EBM process parameters in modulating surface properties relevant to cell–biomaterial interactions. These findings underscore the critical influence of scan speed on the multifunctional performance of Ti-6Al-4V-ELI for biomedical applications. Full article

The materials tribology community has identified that the transfer film attached to the surface of the counterpart metal during the friction process is not only closely related to the filler modification material but also a key factor affecting the tribological properties of polymer composites; however, there is a lack of feasible methods to quantify the characteristics of the transfer film. In this study, Nano-ZrO₂ and polyetheretherketone (PEEK) were filled into a PTFE matrix in order to enhance the wear resistance of polytetrafluoroethylene (PTFE). The tribological properties of the modified PTFE composites were tested using a linear reciprocating friction and wear tester, and the entire friction experiment was designed in seven separate stages. Morphological features were extracted and analyzed from photographs of the transfer film acquired by optical microscopy at each friction stage using an image processing program. The thickness and roughness of the transfer film sections were measured using a non-contact profilometer. Abrasive debris were collected, and their morphological features were observed with an electron microscope. The results showed that the synergistic addition of soft PEEK and hard Nano-ZrO₂ particles effectively inhibited interlayer slippage between PTFE molecular chains, dramatically reducing the size and yield of abrasive debris, and facilitated the improvement of the thickness and firmness of the transfer film, which significantly enhanced the wear resistance of the PTFE composites (the lowest volumetric wear rate for Nano-ZrO₂/PEEK/PTFE was only 1.76 × 10⁻⁴ mm³/Nm). Quantitative analyses of the morphological characteristics of the transfer films revealed that the coverage and roundness of the transfer films gradually increase with the friction stroke, while the aspect ratio and texture entropy subsequently decrease gradually. The coverage, area, mean, third-order moments, and consistency of the transfer film strongly correlated with the volumetric wear rate (correlation coefficient |r| > 0.9). Full article

In the correspondence, a novel polished-D-shape photonic crystal fiber sensor structure on the basis of surface plasmon resonance is proposed for measuring analyte refractive index. With the help of the finite element method, sensing performances of the structure have been analyzed through numerical simulations along with a step-by-step optimization. In this design, different capillaries are gathered and processed to form a D-shape silica structure and nano-scale gold material is coated on the flattened surface. With utilization of a thin gold film and solid silica background, the resonance effect is excited and the loss curve has red shift along with an increase in refractive index, which is applied for sensing. From the simulation and calculation results, the final sensor structure achieves the optimal performance where values of maximum and average sensitivity reach 32,000 and 12,167 nm/RIU along with a sensing coverage of refractive index from 1.26 to 1.32. Also, the proposed design obtains a range of resonant wavelength from 1810 to 2540 nm. We believe the proposed sensor can be a potential candidate for organic and biological detection and related applications. Full article

Coating porosity is an important property that supports solid-gas and solid-liquid exchange that can either enhance various science and technological applications or promote damage if not properly controlled. However, non-destructive instrumental techniques for the measurement of porosity on coated walls or surfaces can be quite challenging. Here, a seamless capillary rise technique has been used to determine both the thickness and porosity of a thin silica coating. Uniform coatings were prepared from 5 wt% hydrophobic fumed silica in absolute ethanol and spin-coated at 500–8000 rpm on glass slides. Capillary imbibition of squalane was then controlled into known areas of the resulted hydrophobic nano-porous coatings. The mass of the solid (silica) and the infiltrated oil (squalane) were gravimetrically measured. The porosity of the material was calculated as the percentage fraction of the pore volume while the film thickness was determined as the ratio of the total volume to the area of coverage. Mean values of the porosity and coating thickness calculated from capillary impregnation technique were 86 ± 2% and 3.7 ± 0.2 μm, respectively. The coating thickness obtained was comparable with those revealed by SEM and Dektak profiler measurements. This study highlights the effectiveness of capillary rise as a simple and cost-effective non-destructive technique for assessment of coating thickness and porosity. Full article

A multifunctional nano-films of cellulose acetate (CA)/magnesium ortho-vanadate (MOV)/magnesium oxide/graphene oxide wound coverage was fabricated. Through fabrication, different weights of the previously mentioned ingredients were selected to receive a certain morphological appearance. The composition was confirmed by XRD, FTIR, and EDX techniques. SEM micrograph of Mg₃(VO₄)₂/MgO/GO@CA film depicted that there was a porous surface with flattened rounded MgO grains with an average size of 0.31 µm was observed. Regarding wettability, the binary composition of Mg₃(VO₄)₂@CA occupied the lowest contact angle of 30.15 ± 0.8^o, while pure CA represents the highest one at 47.35 ± 0.4°. The cell viability % amongst the usage of 4.9 µg/mL of Mg₃(VO₄)₂/MgO/GO@CA is 95.77 ± 3.2%, while 2.4 µg/mL showed 101.54 ± 2.9%. The higher concentration of 5000 µg/mL exhibited a viability of 19.23%. According to optical results, the refractive index jumped from 1.73 for CA to 1.81 for Mg₃(VO₄)₂/MgO/GO@CA film. The thermogravimetric analysis showed three main stages of degradation. The initial temperature started from room temperature to 289 °C with a weight loss of 13%. On the other hand, the second stage started from the final temperature of the first stage and end at 375 °C with a weight loss of 52%. Finally, the last stage was from 375 to 472 °C with 19% weight loss. The obtained results, such as high hydrophilic behavior, high cell viability, surface roughness, and porosity due to the addition of nanoparticles to the CA membrane, all played a significant role in enhancing the biocompatibility and biological activity of the CA membrane. The enhancements in the CA membrane suggest that it can be utilized in drug delivery and wound healing applications. Full article

In this paper, the tribological properties of polytetrafluoroethylene (PTFE) composites filled with Nano-ZrO₂ and polyetheretherketone (PEEK) particles were tested for sliding friction against a counterpart metal (ASTM 1045 steel) using a linear reciprocating friction and wear experimental machine. Data on tribological performance and optical images of the transfer film were obtained at various friction stages for the material. MATLAB software was employed to develop quantitative analysis procedures for the morphological characteristics of the transfer film. The program enables image enhancement and morphological processing of transfer film images, then identifies, extracts, and quantifies the geometric and textural properties of the transfer film as a foundation for analyzing the variation of the characteristics and their relationship to the tribological properties of the material. The results demonstrated that the geometric, morphological, and textural characteristics of the transfer film were dynamically developing during the friction process, with noticeable differences between various friction stages and a significant impact on the tribological properties of the material. Quantitative analysis revealed a good correlation between the trends of some morphological and textural characteristics (the coverage, area, diameter, roundness, consistency, and texture entropy) of the transfer film and the wear resistance of the PTFE composite. Therefore, these morphological and textural characteristics can thus be used to quantify the transfer film quality and utilized as an indirect indicator of the tribological properties of the material. Full article

Nanotechnology is a discipline of science and engineering that emphasizes developing, modifying, characterizing, and using nanoscale components in a variety of applications. Owing to their multiple advantages, including adhesion strength, surface hardness, long-term and extra-high-temperature corrosion resistance, improvement of interfacial behavior, etc., nanocoatings are efficiently utilized to minimize the influence of a corrosive environment. Additionally, nanocoatings are often applied in thinner and finer concentrations, allowing for greater versatility in instrumentation and reduced operating and maintenance costs. The exemplary physical coverage of the coated substrate is facilitated by the fine dimensions of nanomaterials and the significant density of their grounded boundaries. For instance, fabricated self-healing eco-sustainable corrosion inhibitors including PAC/CuONPs, PAC/Fe₃O₄NPs, and PAC/NiONPs, with uniform distributions and particulate sizes of 23, 10, and 43 nm, correspondingly, were effective in producing PAC/MONPs nanocomposites which exhibited IE% of 93.2, 88.1, 96.1, and 98.6% for carbon steel corrosion in 1M HCl at the optimum concentration of 250 ppm. Therefore, in this review, further steps are taken into the exploration of the significant corrosion-mitigation potential and applications of nanomaterial-based corrosion inhibitors and nano-modified coatings, including self-healing nanocoatings, natural source-based nanocoatings, metal/metallic ion-based nanocoatings, and carbon allotrope-based nanocoatings, to generate defensive film and protection against corrosion for several metals and alloys. These have been illuminated through the in-depth discussion on characterization techniques such as scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), etc. After providing a general summary of the various types of nanomaterials and their protective mechanisms in wide corrosive media, we subsequently present a viewpoint on challenges and future directions. Full article

The gypsum and calcite scaling propensities of the thin-film composite polyamide (PA-TFC) reverse osmosis (RO) membrane, modified with a tethered surface layer of polyacrylic acid (PAA) chains, was evaluated and compared to the scaling of selected commercial RO membranes. The tethered PAA layer was synthesized onto a commercial polyamide membrane (i.e., base-PA) via atmospheric pressure plasma-induced graft polymerization (APPIGP). The PAA nano-structured (SNS) base-PA membrane (SNS-PAA-PA) was scaled to a lesser degree, as quantified by a lower permeate flux decline and surface imaging, relative to the tested commercial membranes (Dow SW30, Toray SWRO, and BWRO). The cleaning of gypsum-scaled membranes with D.I. water flushing achieved 100% water permeability recovery for both the SNS-PAA-PA and Dow SW30 membranes, relative to 92–98% permeability restoration for the Toray membranes. The calcium carbonate scaling of SNS-PAA-PA membranes was also lower relative to the commercial membranes, but permeability recovery after D.I. water cleaning was somewhat lower (94%) but consistent with the level of surface scale coverage. In contrast, the calcite and gypsum-scaled membrane areas of the commercial membranes post-cleaning were significantly higher than for the SNS-PAA-PA membrane but with 100% permeability recovery, suggesting the potential for membrane damage when mineral scaling is severe. Full article

Magnetic properties of ferromagnetic nanofilms on non-magnetic substrate are examined by computer simulation. The substrate influence is modeled using the two-dimensional Frenkel-Kontorova potential. The film has a cubic crystal lattice. Cases of different ratio for substrate period and ferromagnetic film period are considered. The difference in film and substrate periods results in film deformations. These deformations result in a change in the magnetic properties of the film. The Ising model and the Metropolis algorithm are used for the study of magnetic properties. The dependence of Curie temperature on film thickness and substrate potential parameters is calculated. Cases of different values for the coverage factor are considered. The deformation of the film layers is reduced away from the substrate when it is compressed or stretched. The Curie temperature increases when the substrate is compressed and decreases when the substrate is stretched. This pattern is performed for films with different thicknesses. If the coating coefficient for the film is different from one, periodic structures with an increased or reduced concentration of atoms are formed in the film first layer. These structures are absent in higher layers. Full article

In the present work, we developed hybrid nanostructures based on ZnO films deposited on macroporous silicon substrates using the sol–gel spin coating and ultrasonic spray pyrolysis (USP) techniques. The changes in the growth of ZnO films on macroporous silicon were studied using a UV-visible spectrometer, an X-ray diffractometer (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD analysis revealed the beneficial influence of macroporous silicon on the structural properties of ZnO films. SEM micrographs showed the growth and coverage of ZnO granular and flake-like crystals inside the pores of the substrate. The root mean square roughness (RMS) measured by AFM in the ZnO grown on the macroporous silicon substrate was up to one order of magnitude higher than reference samples. These results prove that the methods used in this work are effective to cover porous and obtain nano-morphologies of ZnO. These morphologies could be useful for making highly sensitive gas sensors. Full article

Nano carbons, such as graphene and carbon nanotubes, show very interesting electrochemical properties and are becoming a focus of interest in many areas, including electrodeposition of carbon–metal composites for battery application. The aim of this study was to incorporate carbon materials (namely oxidized multi-walled carbon nanotubes (ox-MWCNT), pristine multi-walled carbon nanotubes (P-MWCNT), and reduced graphene oxide (rGO)) into a metallic tin matrix. Formation of the carbon–tin composite materials was achieved by electrodeposition from a choline chloride-based ionic solvent. The different structures and treatments of the carbon materials will create metallic composites with different characteristics. The electrochemical characterization of Sn and Sn composites was performed using chronoamperometry, potentiometry, electrochemical impedance, and cyclic voltammetry. The initial growth stages of Sn and Sn composites were characterized by a glassy-carbon (GC) electrode surface. Nucleation studies were carried out, and the effect of the carbon materials was characterized using the Scharifker and Hills (SH) and Scharifker and Mostany (SM) models. Through a non-linear fitting method, it was shown that the nucleation of Sn and Sn composites on a GC surface occurred through a 3D instantaneous process with growth controlled by diffusion. According to Raman and XRD analysis, carbon materials were successfully incorporated at the Sn matrix. AFM and SEM images showed that the carbon incorporation influences the coverage of the surface as well as the size and shape of the agglomerate. From the analysis of the corrosion tests, it is possible to say that Sn-composite films exhibit a comparable or slightly better corrosion performance as compared to pure Sn films. Full article

The effect of copper addition on the corrosion resistance and mechanical properties of binary Zr_100–xCu_x (x = 30, 50, 80, 90 at.%) glassy coatings was investigated by means of electrochemical measurements, scanning electron microscopy (SEM), energy dispersive analysis spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and nano-indentation techniques. The corrosion resistance in 0.01 M deaerated H₂SO₄ solution and the mechanical properties of the Zr-Cu glassy coatings depend considerably upon the copper content in the glassy matrix. The top surfaces of the Zr-Cu coatings with lower Cu content were covered by a compact protective ZrO₂ passive film. The competition between the oxidation of Zr atoms (ZrO₂ film formation) and the oxidation–dissolution of Cu atoms assumed the most important role in the electrochemical behavior of the Zr-Cu glassy coatings. The generation of ZrO₂ on the surface benefited the formation of passive film; and the corrosion resistance of the metallic glass coatings depended on the coverage degree of ZrO₂ passive film. The evolution of free volume affected both the mechanical and corrosion behaviors of the Zr-Cu glassy coatings. Full article