Advances in Materials Science and Engineering

Machining hard materials with 45–48 HRC is difficult in turning operation because of the improvident cutting parameter selections for the operation. The OHNS (AISI/SAE-01–48HRC) steel is mainly preferred for the production of shafts, gears, cams, and press tools. The OHNS material was turned at a dry state using VP-coated carbide inserts. The seventeen experimental trials were designed by central composite design (CCD) with different levels of cutting parameters, like feed rate, cutting speed, and depth of cut. Design Expert-11 software desirability approach and TOPSIS (Technique for Order Preference by Simulating the Ideal Solution) were used to analyse the experimental results to obtain a single optimal solution that defines better results on metal removal rate (MRR) and surface finish (Ra). RSM solution with 81.3% desirability, the cutting speed of 60 m/min, feed rate of 0.08 mm/rev, and depth of cut 1 mm as the optimal cutting parameters; similarly, TOPSIS algorithm calculation identifies the cutting parameter combinations, such as 40 m/min cutting speed, 0.09 mm/rev feed rate, and 1 mm depth cut to enrich the quality of the machined steel; however, the desirability approach cutting parameter setting is better for the surface finish achievement, while TOPSIS solution is better to obtain significant MRR. The confirmation test results validated for the predicted values of both approaches; as such, the experimental results were maintained better convenience than the predicted one. For the optimum cutting parameter combinations, an MRR of 22.032 gm/min and surface roughness of 0.781 μm were obtained at 60 m/min cutting speed, 0.08 mm/rev feed rate, and 1 mm depth of cut.

Ceramic matrix composites (CMCs) are a category of advanced materials which have gained significant interest recently due to their remarkable mechanical and thermal characteristics. These composites are composed of ceramic fibers, particles, or other types of ceramics incorporated in a ceramic matrix and have shown the capability to be implemented in several sectors, including aerospace, energy, and biomedical engineering. This review paper will provide a synopsis of the current scenario and recent progress in CMCs, including materials and processing techniques, characterization methods, and applications. The paper discusses the advantages and limitations of CMCs, recent advancements, and future trends in research. The microstructural and mechanical properties of CMCs are also reviewed, highlighting their potential for various applications. The paper’s conclusion delivers a summary of the essential findings and a discussion of future directions for CMC research.

Using synthetic polymers in the production of superabsorbent polymers offers significant advantages such as low cost, extended service life, and a high water absorption rate. However, concerns about the environmental impact and potential adverse effects on plant growth arise from the degradation products of these polymers after disposal. In addition, handling these polymers can cause rashes, irritations, and even toxic shock syndrome. To overcome these issues, researchers are exploring the synthesis of superabsorbent polymers from natural sources. Cottonseed protein is identified as a potential natural polymer for the synthesis of natural superabsorbent polymers. Notably, there is no existing research on hydrogel synthesis using cottonseed protein and 2-acrylamido-2-methylpropanesulfonic acid (AMPS). This study addresses this gap by focusing on modifying cottonseed protein (CSP) through graft copolymerization, utilizing the partially neutralized form of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) in a water-based solution. N,N-methylene bisacrylamide serves as the crosslinking agent, while potassium persulfate (PPS) and sodium bisulfite (SBS) function as redox initiators. The optimization of hydrogel synthesis conditions was achieved using Design Expert-11 software, adjusting the AMPS to CSP ratio. The research reveals that the hydrogel reaches its maximum swelling capacity (195.7 g/g) with 0.03 g of MBA, 0.01 g of PPS, 0.01 g of SBS, and a 1wt% AMPS to CSP ratio. Swelling properties were assessed under diverse pH conditions, and the study delved into swelling kinetics (both pseudo-first-order model and pseudo-second-order model) and performance under different loads. Grafting evidence was validated through FTIR analysis. The maximum water uptake was obtained when there was no load, and the pH value was around neutral (7). In conclusion, the results indicate that the developed hydrogel holds a promise for applications in water retention, reducing water loss, and serving as an environment-friendly, biocompatible superabsorbent polymer so we can use such hydrogel in biomedical applications.

To address the shortage of the aggregate used in a hot mix asphalt (HMA) pavement in Guangxi, properties such as the aggregate crushing, polished stone, and Los Angeles abrasion values of a type of hard sandstone aggregate used in HMA were tested after various conditioning treatments. The hard sandstone aggregate met the technical requirements for aggregate in HMA. In addition, the influence of the Marshall compaction on the hard sandstone aggregate-combined grading was tested. The combined grading curve changed a little, and the aggregate satisfied the corresponding technical requirements. Therefore, according to the abovementioned results, the hard sandstone aggregate can be used as a coarse aggregate in HMA.

Carbonation resistance ability is one of the most important durability-related proprieties of cement-based materials. Through the carbonation depth experiment, isothermal conduction calorimetry, XRD, BET, and water vapor sorption, the effect of calcium nitrite (Ca(NO₃)₂) on the carbonation properties of cement-based materials is obtained. The result indicates that the addition of Ca(NO₃)₂ improves the carbonation resistance property of cement-based materials if the hydration of cement pastes and microstructure is modified earlier without affecting the late hydration process. In addition, the refined pores and higher tortuosity cut down the channels, thereby impeding the ingress of carbon dioxide gas into cementitious materials, as confirmed by BET and water vapor sorption. The Ca(NO₃)₂ exhibits high performance in improving the carbonation resistance and extending the life of strengthened concrete.

This study explores the investigations of bamboo fiber-reinforced polyester composites with chopped glass fiber (CGF) filler, focusing on addressing the challenges of low mechanical properties, limited thermal stability, and high moisture absorption. The two types of composites were fabricated using the hand layup method, that is, long unidirectional 0° bamboo fiber (BF) and randomly oriented short bamboo fiber (BP) reinforced a polyester matrix with chopped glass fiber (CGF) filler. By incorporating CGF filler, significant improvements in mechanical properties were achieved across both types of bamboo fiber, surpassing the limitations of unfilled composites. Notably, the composite formulation consisting of 40% wt. of unidirectional 0° BF and 5% wt. of CGF filler exhibited superior ultimate tensile strength, flexural strength, impact strength, water absorption, and thermal stability. This composite demonstrated remarkable enhancements, with increases of up to 131.22 MPa, 128.76 MPa, 113.3 kJ/m², 1.94% water absorption, and up to 255°C (representing a 10% improvement) in thermal stability compared to the unfilled composite. Statistical analysis revealed quadratic models for the mechanical properties of long unidirectional 0° bamboo fiber composites, while water absorption exhibited a linear two-factor interaction model. For randomly oriented short bamboo fiber, the models for tensile, flexural, and water absorption properties were linear, while the impact energy model showed a quadratic relationship. These statistical models provide valuable insights into predicting the properties of bamboo fiber-reinforced polyester composites. This research underscores the significance of bamboo fiber-reinforced polyester composites in wall partition systems. This study paves the way for improved performance in these areas. The findings highlight the potential of incorporating CGF filler, enabling enhanced mechanical strength, increased thermal stability, and improved resistance to moisture-related issues. The derived statistical models offer valuable guidance for predicting the properties of these composites, facilitating their application and adoption in the construction industry.