Advances in Materials Science and Engineering

Coffee husk (CH) and brewery spent grain (BSG) fibers are sustainable industrial residues that consist of cellulose. The present study aimed at the extraction of cellulose from CH and BSG fibers and to study the effect of alkali-hydrogen peroxide (5% NaOH–7% H₂O₂) treatment during the extraction by characterizing the extracted cellulose. Characterization of cellulose particles, such as crystallinity, functional groups, thermal properties, and morphology, was conducted by performing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), and scanning electron microscopy (SEM), respectively. The finding shows that the maximum cellulose yields obtained from CH and BSG fibers are 37.3% and 26.5%, respectively. From the XRD results, the cellulose obtained from CH fiber (C-CH) and from BSG fiber (C-BSG) showed diffractive peaks with the highest intensity of approximately 1,003 and 1,236 counted at 2θ = 22°, respectively. A reduction in the absorption of peaks was observed on the FTIR spectrum for both C-BSG and C-CH samples at different wavelengths. SEM demonstrated that the surface roughness of the celluloses was enhanced. TGA showed that the maximum temperature decomposition observed for both C-CH and C-BSG is 360°C and 380°C, respectively. Generally, in this study, alkali-hydrogen peroxide (5% NaOH–7% H₂O₂) treatment was effectively used for the treatment of BSG and CH fibers for the extraction and surface modification of cellulose particles. The extracted cellulose in the present study can be used as an alternative to conventional cellulose for the manufacturing of biocomposite materials, preparation of particle boards and furniture, and production of food packaging materials.

This paper explores the need for establishing a microwave link between Bahir Dar and Woretta as an alternative communication solution to the existing optical fiber infrastructure. Microwave links offer an effective way to overcome challenges posed by rugged terrains and unfavorable environmental conditions that hinder the deployment of fiber optics. As Woretta emerges as a key economic and investment hub within the Amhara Region, demand for reliable and efficient communication is expected to grow significantly. The study encompasses various aspects of planning and designing the microwave link, including site surveys, consideration of fade margins, frequency planning, link budget calculations, and assessing the feasibility and reliability of the proposed link. The paper employs LINKPlanner 5.4.1 software to simulate and validate the results. Due to terrain constraints, a direct link between Bahir Dar and Woretta is not feasible. Instead, a two-hop link is proposed, involving transmission from Bahir Dar to Zege, and then from Zege to Woretta. This alternative configuration ensures optimal connectivity while addressing the terrain limitations. By presenting a comprehensive analysis and simulation of the microwave link, this paper provides valuable insights into the planning and implementation of a robust communication infrastructure. The proposed microwave link will offer a reliable and efficient alternative to the existing optical fiber network, ensuring uninterrupted connectivity to support the region’s growth and development.

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.