Solid State Phenomena Vol. 356

Abstract: Ni-P coatings were prepared on low carbon steel substrates using the pulse electrodeposition method. The influence of the pulse duty cycle on the phosphorus content and hardness of the Ni-P coatings was investigated. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were employed to examine the surface morphology and chemical composition of the Ni-P coating layers. The results showed that an increased pulse duty cycle (20% - 80%) led to a decreased phosphorus content from 17.81 wt.% to 13.71 wt.%. The microhardness values were found to have an inverse relationship with the phosphorus content. The highest hardness of 538.22 ± 12.92 HV_0.1 was obtained from the sample produced with a duty cycle of 80%, which had the lowest P content of 13.71 wt.%.

Abstract: The present research aimed to evaluate the effect of nickel-based electrochemical metallization (EMNi) on the quality and performance of electric motor components, compared to high-velocity oxy-fuel (HVOF) thermal spray coating, the most widely used coating in the mining industry. The experiment was conducted using motor components comprised of 4340 VCN steel, 4140 VCL steel, 1045 steel, and stainless steel, which underwent both treatments. The surface temperature of the components was monitored during the processing stage, followed by evaluations of their Rockwell hardness (HRC) and surface characteristics (taper, ovality, parallelism, finish, wear) at the onset (day 0) and after 2 years of use the results indicate that EMNi delivers electric motor components with superior finishes and extended warranty and service life in comparison to HVOF.

Abstract: Silver nanoparticles (AgNPs) were synthesized by a chemical method in which cellulose nanofibers (CNFs) extracted from pineapple leaves served as a stabilizing and reducing agent. In this study, pineapple leaves were oxidized by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation with sodium hypochlorite (NaClO) to obtain CNFs. After the oxidation, the transformation from hydroxyl groups to carboxylate groups of cellulose was confirmed by Fourier-transform infrared spectroscopy (FTIR), and TEMPO-oxidized CNFs with a higher carboxylate content were obtained. Then, TEMPO-oxidized CNFs with a carboxylate content of 2.49 mmol/g and non-oxidized CNFs with a carboxylate content of 0.68 mmol/g were used as a reducing agent to synthesize AgNPs. The formation of AgNPs was confirmed by color changes of the Ag solutions from white to yellow. Furthermore, AgNPs with an average diameter of 76.5 ± 22.15 nm were obtained when TEMPO-oxidized CNFs were used as a reducing agent, while non-oxidized CNFs generated AgNPs with a larger particle size of 181.2 ± 66.16 nm. This suggested that the TEMPO-oxidized CNFs could be used as a stabilizing and reducing agent for the synthesis of AgNPs with smaller diameters.

Abstract: In this study, Chitosan-Xyloglucan encapsulated Titanium dioxide was prepared by in-situ method for coating Silk fabric. FT-IR XRD characterized the functional groups and formation of crystallization of composite film. SEM analysis showed the immobilization of composite film on the surface of silk fabric. The coated silk fabrics were stained with methylene blue, and the stain removal efficiency was evaluated. The results showed that the composite film was deposited onto the silk fabric. The functional groups showed peaks around 1635 to 1636 and 400 to 500 cm^-1 that indicate the presence of C=N groups of Chitosan-Xyloglucan and Ti-O groups of TiO₂ on the composite, respectively. The XRD results indicated that the TiO₂ prepared by the sol-gel method was an anatase crystalline structure. The mechanical properties showed the composite film was superior to the Chitosan-Xyloglucan, TiO₂, and uncoated silk fabric. Finally, the methylene blue degradation capability was investigated. The coated silk fabric has insignificantly removing methylene blue stain than the untreated silk fabric, but it is noticeably repellent to stain.

Abstract: An improved melt-blowing method have developed to manufacture the organic nonwoven nanofibers through our previous study. As a parallel phase, this study explores the potential of polylactic acid (PLA) nanofibers as a plant growth substrate, emphasizing the unique properties and performance when mixed with pellets. Preliminary experiments comparing different fiber materials, cultivated crops, and fiber diameters demonstrate the favorable characteristics of PLA, such as wettability and growth promotion. Comparative experiment with rockwool, a commonly used medium, shows that PLA nanofibers exhibit superior growth performance. On the other hand, a solidified PLA medium is produced and tested. Hydroponic tests using solidified medium configurations with varying fiber diameters and soil conditioners further confirm the benefits of PLA as a medium for plant growth. The findings suggest that PLA nanofibers have the potential to revolutionize cultivation practices, providing sustainable and environmentally friendly alternatives to traditional substrates.

Abstract: Chitin is the second most abundant biopolymer in the world. Herein, deacetylated chitin nanofibers (dChNFs) through partial deacetylation were initially prepared, and dChNFs were subsequently added into chitosan (CS) to develop the biodegradable coatings to extend the shelf life of bananas. The degree of deacetylation and the average diameter of the obtained dChNFs were 29.12 % and 19.49 ± 3.1 nm, respectively. The addition of dChNFs into CS at the ratio of 50:50 decreased the water vapor permeability (WVP) from 4.56 × 10^–11 g/m·s·Pa to 3.81 × 10^–11 g/m·s·Pa. Moreover, three different suspensions of CS, dChNFs, and CS/dChNFs were applied as coatings on Hom–Thong bananas via the dipping technique. The application of the CS/dChNFs coating showed a significant postponement in the color change of the peel (from green to yellow) to 22 days, compared to 9 days for uncoated bananas. The weight of the bananas coated with CS/dChNFs exhibited a weight loss of 26.53 % day^–1, which was lower than that of the uncoated bananas (30.71 % day^–1). This suggested that the CS/dChNFs coating would be efficiently used to prolong the shelf life of bananas, reducing food waste.

Abstract: This work identifies the effect of loading benzotriazole (BTA) on mesoporous silica nanoparticles (MSN) as an initial step in preparing a self-healing corrosion-protective coating with environmentally friendly precursors, rice husk, which advantages cheaper, renewable, and contains relatively high silica. This research uses the sol-gel method to synthesize MSN. Based on the result, it is known that the loading of BTA strongly affects the porosity properties of these nanoparticles. The pore sizes increase as the surface areas and pore volumes decrease. However, the silicone composition shrinks. Based on pore size, it is known that all the samples in this work were mesoporous materials (over 2 nm) with spherical and globular morphologies (like coral reefs).

Abstract: We present a theoretical study of the optical absorption of the group-V transition-metal dichalcogenids TaX₂ (X = S, Se) by using the Wannier tight-binding Hamiltonian method. The absorption spectra show diverse and interesting features, including dominant peaks and shoulder-like structures. We provide an in-depth discussion on the optical spectral structures based on the energy dispersion and density of states. This work can advance the understanding of optical properties of two-dimensional materials which is important in the search for proper candidates for next-generation electronic devices.