Materials Letters: X最新文献

In the present investigation, the microencapsulated phase change material (PCM) thermal kinetics for low-temperature thermal energy storage applications (32 °C–53 °C) is analysed. Microencapsulated PCMs selected are CaCl₂·6H₂O, n-Hexadecane, n-Octadecane, n-Eicosane, Capric/Lauric acid, Paraffin wax (C₃₀H₆₂), and Palmitic acid (C₁₆H₃₂O₂), respectively. Ambient air is selected as the external/heat transfer fluid which interacts with PCM materials. The thermal kinetics of microencapsulated PCMs is evaluated by selecting the solid-liquid interface position with melting time and molten fraction as the performance evaluation parameters. Among all the phase change materials, the best PCM is found to be CaCl₂·6H₂O with 4 cm of PCM diameter, 53 °C of external fluid temperature, and 106 min of melting time.

Laser-based processing techniques have proven to be an effective option of modifying polymer surfaces. In this context Direct Laser Interference Patterning in conjunction with the polygon scanner technique is used to fabricate textured polystyrene surfaces through ultra-fast beam deflection. This is achieved by using a high-average power picosecond laser in combination with a polygon mirror-based scanning system. The two-beam DLIP optical configuration leads to the formation of line-like structures with a spatial period of 21.0 µm. The influence of the scanning speed and the repetition rate on the structure formation is investigated, allowing structure heights up to 23 µm. The formation of the micro-structure was found to result from swelling and ablation mechanisms. By applying scanning speeds of 350 m/s, a throughput of 1.1 m²/min is reported for the first time using this method.

In this study, a uniform anomalous eutectic is formed in a slow cooling process of undercooled hypoeutectic Ni-B alloy. The longer the cooling time, the higher the hardness of the Ni₃B phase. This is a result of higher concentration of boron being arrested by the Ni₃B phase.

With the intense development of nanotechnology, copper oxide nanoparticles have terrible immense applications in electrical, optical and Bio-medical applications. To safeguard the environment and to mortify the toxicity in chemicals, the present work was carried out for synthesizing Pure and Silver (Ag) doped Copper Oxide (CuO) nanoparticles of different concentrations using Moringa Oleifera leaf extract and it shows a good result towards antimicrobial agents. These green synthesized nanoparticles were subjected to characterization techniques, X- ray Diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X- ray Analysis (EDAX), Fourier Transform Infrared spectroscopy (FTIR) and Ultraviolet–Visible spectroscopy (UV). From XRD, the average crystallite size for pure and silver doped copper oxide nanoparticles was found to be in the nanometer range and it belongs to a monoclinic structure. The surface morphology and the elemental compositions of nanoparticles were confirmed by SEM with EDAX. Functional groups were observed by FTIR spectra. From the optical absorption spectrum, the bandgap for pure copper oxide was found to be 1.2 eV, while increasing the dopant concentrations shows enhancing results towards optical properties.

Renewable biomass as a sustainable feedstock has been enormously explored for the manufacturing of high value-added products such as biofuels, commodity chemicals, and new bio-based materials. The present paper describes the synthesis of a series of natural zeolite based catalysts by loading different weight percentage of phosphomolybdic acid. The efficiency of catalysts were checked by conversion of carbohydrate (glucose and fructose) to 5-HMF, which is an important industrial chemical used in the production of various value-added chemicals, materials and biofuels.

Zinc Oxide nanoparticles (ZnO NPs) were synthesized as a powder using the oxalate co-precipitation method after calcination at 700 °C. Zine sulfate was used as a zinc soluble source, and oxalic acid was used as a Catalyst. The reaction was carried out at room temperature condition. The resulted powder was characterized by XRD analysis before calcination and after calcination at 500 °C, and 700 °C. The results show that the crystal structure is hexagonal with a = 3.249 Å, c = 5.205 Å. The FeSEM results showed particles of 80 nm.

With good electrochemical performances and cost advantages, sodium-ion batteries (SIBs) have great potential in energy storage and other fields. It is crucial to research anode materials for SIBs with high performance and low cost to promote large-scale industrialization. In this study, the amorphous carbon-based anodes prepared by one-step carbonization of bituminous coal were firstly reported. When the materials were worked as anodes for SIBs in the voltage range of 0–1.5 V, an excellent reversible capacity of 270 mAh·g⁻¹ and an initial coulombic efficiency (ICE) of 84.4% were achieved at a current density of 35 mA·g⁻¹. More impressively, the carbon anodes possess merits of low cost, making the designed carbon anodes practicable to the industrial applications.

This study aims to develop spay reactive powder concrete (SRPC) with excellent mechanical and self-sensing properties by using carbon fiber (CF) as reinforcement material in combination with RPC base mix ratio. A Box–Behnken model was designed using the response surface method to study the influence of silica fume (SF), fly ash (FA), and CF on the compressive strength and strain sensitivity coefficient (SSC) of SRPC with different dosages. Variance regression was used to analyze the interaction of each factor on the index, and multi-index optimization technology was utilized to optimize the response scheme. Results show that the compressive strength is 107.272 MPa and SSC is 34.429 under optimized conditions of 18% SF, 17.097% FA, and 0.5% CF. The strain sensitivity coefficient of SRPC is 5–17 times higher than that of the conventional strain gauge used for monitoring concrete. SRPC was prepared by adjusting the dosage of the water reducer and stirring time at a 0.2 water–binder ratio.

Continuous Kr ion irradiation at 400 °C with damage level up to 40 dpa was performed in Zircaloy-4 to investigate the surface damage features of α-Zr matrix. Atomic force microscopy confirms that the irradiation induced surface damage is primarily in the form of damaged pits. The increasing Ra value indicates the gradual surface roughening process with continuous irradiation. The irradiation-induced surface roughening mechanism is suggested as three stages: stage I, the formation and growth along depth direction of damaged pits at low doses; stage II, the extension of damaged region within the surface; stage III, layer by layer removal of surface atoms once the undamaged matrix is depleted.