Abstract In this study, the effects of CoFe 2 O 4 (as hard magnetic) nanoparticle addition and MnFe 2 O 4 (as soft magnetic) nanoparticle addition in carbonyl iron powder-based magnetorheological fluid were investigated. Both types of nanoparticles (CoFe 2 O 4 and MnFe 2 O 4 ) were analyzed for grain morphology shape using field emission scanning electron microscopy (FESEM) and magnetic properties using a vibrating sample magnetometer (VSM). FESEM and VSM analysis revealed that CoFe 2 O 4 nanoparticles exhibit smaller grain size than MnFe 2 O 4 , while the coercivity and remanence of CoFe 2 O 4 nanoparticles are higher than MnFe 2 O 4 . Three types of MRF samples were made (CIP MRF without nanoparticles, CIP MRF with CoFe 2 O 4 nanoparticles and CIP MRF with MnFe 2 O 4 nanoparticles). The concentration of nanoparticles addition was selected as 1wt%, while the concentration of dispersed particles was kept at 70wt%. The results showed that the addition of both types of nanoparticles to MRF to the MRF increase the shear stress and storage modulus. However, the addition of both types of nanoparticles has a negative effect during the sudden removal of magnetic field test. In sudden removal magnetic fields, the presence of nanoparticles in MRF causes the shear stress value of MRF to be higher and the value is not stable.

Abstract Although bioactive glass (BG) exhibits excellent bioactivity and strong potential for bone-grafting applications, its inherent brittleness limits its use in load-bearing conditions. This study focuses on improving the mechanical performance of bioactive glass by incorporating reinforcing phases and natural biopolymers to expand its biomedical applicability. The bioactive glass (46S19) and fluorapatite (FA) powders were synthesized via the sol–gel method using an organic acid as a catalyst. X-ray diffraction (XRD) confirmed the amorphous nature of BG and the crystalline structure of FA, providing essential insights into their phase composition and potential bioactivity. Hybrid bio-nanocomposite samples were fabricated by uniaxial pressing at 624 MPa followed by heat treatment at 1,000 °C for 2 h. Three reinforced composites containing 5, 15, and 25 wt% FA were prepared, along with a pure BG sample. A natural biopolymer coating composed of gum arabic (GA) and Ajwa date-seed (DS) powder was applied using the dip-coating technique to improve surface integrity and biocompatibility. Field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy (FE-SEM/EDS) analyses were used to evaluate morphology, bonding, porosity, and crystallization behavior. Mechanical characterization through Vickers microhardness and splitting tensile strength tests revealed that FA incorporation enhanced both hardness and strength by promoting microstructural densification and grain growth during heat treatment. The 25 wt% FA composite exhibited the best performance, with tensile strength values ranging between 10.5 MPa and 12.5 MPa – comparable to natural bone. These findings confirm that fluorapatite reinforcement combined with DS–GA coating provides a cost-effective and biofunctional route to develop hybrid bio-nanocomposites suitable for bone-graft and load-bearing biomedical applications.

Abstract This study investigates the macroscopic mechanical behavior of steel wire ropes under corrosive conditions, specifically focusing on the effects of sulfuric acid exposure. The goal is to simulate and analyze the degradation process in service by conducting monotonic tensile tests on both undamaged and artificially pre-damaged 19 × 7 circular strand steel wire ropes. These ropes were subjected to varying levels of corrosion in order to evaluate their mechanical properties. To systematically explore the influence of multiple factors on the degradation process, the Taguchi method was applied, utilizing an L9 orthogonal array with three experimental factors: sulfuric acid concentration, immersion time, and the number of strands removed from the wire rope. Each factor was tested at three levels to determine its impact on corrosion resistance. Steel wire ropes were exposed to sulfuric acid concentrations of 20 %, 30 %, and 40 % for immersion times of 1–3 h, with 0, 2, and 4 strands removed. The maximum tensile strength decreased from 516.415 N in the reference sample to between 482.83 N and 35.63 N after corrosion, corresponding to a 6.5–93.1 % reduction. Statistical analyses, including the signal-to-noise ( S / N ) ratio and analysis of variance (ANOVA), were used to identify the optimal parameter settings for maximizing mechanical performance. The results indicate that the number of strands removed has the most significant influence on the rope’s mechanical properties, followed by the concentration of sulfuric acid and the immersion time. A confirmation test was performed to verify the accuracy and consistency of the optimal parameter configuration, ensuring the reliability of the findings. This study highlights the importance of optimizing key parameters to enhance the corrosion resistance of steel wire ropes, thus extending their service life in corrosive environments. The use of the Taguchi method in this context demonstrates its effectiveness in optimizing mechanical properties and provides valuable insights for improving the durability of wire ropes in industrial applications.

Abstract This study systematically investigates Waste Septage Ash (WSA) as a sustainable filler in bituminous mixtures, comparing its performance with Municipal Solid Waste Ash (MSWA) and Sewage Sludge Ash (SSA) through comprehensive mechanical, durability, and environmental assessments. Nine performance parameters were evaluated following ASTM/AASHTO standards with statistical validation ( n = 3, ANOVA, p < 0.05). Results demonstrated WSA superiority with statistically significant improvements: 8.7 % higher Marshall Stability (11.2 ± 0.4 kN vs. 10.3 ± 0.5 kN for SSA, p < 0.01), 9.2 % enhanced ITS (950 ± 28 kPa), 86 % TSR exceeding AASHTO minimum (80 %), 12.5 % lower creep rate, and 15 % superior fatigue life (98.7 ± 4.2 × 10 3 cycles). SEM-EDS analysis confirmed continuous bitumen film formation attributed to WSA’s optimal SiO 2 /CaO ratio (3.2:1) and fine particle morphology (<63 μm). Life cycle assessment revealed 47 % CO 2 reduction and 40 % energy savings compared to conventional limestone filler. The findings establish WSA as a technically viable and environmentally sustainable alternative filler, contributing to circular economy principles and UN Sustainable Development Goals 11 and 12.

Abstract The impact of quenching treatment on the mechanical characteristics of Cu–Zn–Sn-based SMAs is investigated using nanoindentation approach conducted at 100–200 mN loads. Two compositions labeled A (Cu 71·19 Zn 15·6 Sn 12·1 Fe 1.05 ) and B (Cu 63·73 Zn 26·1 Sn 9·3 Fe 0.82 ) were subjected to step/up-quenching procedures. The microstructure was composed of Cu 4 and γ -Cu 5 Zn 8 parent phases with sparse distribution Fe 4 and Cu 3 Sn precipitates in the matrix for the up/step-quenched A samples. The step-quenched B samples comprised Cu 3 Sn and Fe 4 Zn 9 precipitates in Cu4 and γ -Cu 5 Zn 8 parent phases, whereas the up-quenched B samples is composed of Cu 3 Sn and Fe 7 Zn 3 second phases. The nanomechanical properties of composition B samples were generally superior to those of composition A samples. For B alloys, the superelasticity increased from 91.91 %, 86.97 %, and 85.01 % at 100 mN load to 93.41 %, 91.80 %, and 88.75 % at 200 mN load for the step-quenched, up-quenched, and direct-quenched samples, respectively. The reduced elastic modulus at 100 mN lie in the range of 122.23–131.84 GPa for the step-quenched samples; 119.86–128.81 GPa for the up-quenched samples; and 116.79–125.16 GPa for the direct-quenched samples. Step-quenching thermal procedure efficiently enhanced the nanomechanical characteristics of the alloys.

Abstract To investigate the ablation mechanism and characteristics of femtosecond laser cutting of CVD diamonds, experimental and theoretical studies were conducted. The effects of different laser parameters on kerf quality were studied. It showed that the original kerf obvious cracks and significant carbonization due to ns-laser cutting process. By adopting green fs-laser with parameters around ablation threshold, kerfs with no microscopic cracks were found with the surface roughness of 5.278 µm. SEM-FIB analysis revealed the average thickness of carbonization layer reduced to 1.206 µm compared with the initial thickness of 2.211 µm. Further experiments were conducted in the nitrogen atmosphere, where the roughness of kerfs furtherly decreased to 2.705 µm with no graphitization layer. It revealed that material removal for CVD diamonds during femtosecond laser processing was mainly occurred via sublimation. The thermal affected region could be effectively suppressed to achieve cold processing effect. XRD analysis of the kerfs indicated the precipitation of graphite phase due to thermal effects during laser process, while the introduction of femtosecond laser with protective gas could effectively suppress graphite phase formation and promote the quality of kerfs, thus achieving the clean kerfs of CVD diamonds.

Abstract The advancement of modern engineering materials with superior mechanical properties such as hardness, toughness, and brittleness presents significant challenges to conventional machining techniques, often leading to tool failure and poor surface finish. To address these limitations, non-conventional machining method; Electrical Discharge Machining (EDM) has developed. The efficiency of EDM is primarily governed by electrical parameters such as current, gap voltage, and the conductivity of electrodes and dielectric fluids. The conductive powder viz. silicon carbide and aluminium powder mixed in dielectric medium is to improve the surface roughness (SR). The incorporation of conductive powders into the dielectric fluid has shown promise in enhancing EDM performance by stabilizing spark generation, thereby improving surface finish. In this study desirability approach method is used to optimize and identify the best SR value. Moreover, the surface characteristics analysed by measuring recast layer thickness, microhardness. The use of aluminium powder showed the better surface finish than silicon carbide.

Abstract Unsaturated polyester resin is the most versatile polymer with wide range of application but it has low impact strength, low elongation at break and low toughness. Its mechanical and microstructural properties can be enhanced by the addition of optimum amount of Nanocellulose, nanosilica fillers and latex liquid rubber. Mechanical and microstructural properties characterization of the composite material (resin, latex rubber and nanocellulose) has been tested for 0.5 %, 1 %, 3 %, & 5 % by weight of the latex liquid rubber as fiber weight fraction. The characterization has been done for tensile, compression, impact, bending, XRD (X-ray powder Diffraction method), FTIR (Fourier Transform Infrared Spectroscopy) and flexural test. The aim is to obtain modified polyester resin nano composite material with enhanced mechanical properties of strength and toughness for industrial and structural application such as packaging, composite matrix for improved vehicle bumper application, water tanker construction, adhesive application and biomedical industries. The composite material mechanical properties has been enhanced about 40 % for the tensile strength, 35 % for flexural, 65 % for compression strength and 10 % for impact strength up on the addition of 2 % nano cellulose with diameter of 10 nm as particle size and 3 % by weight liquid rubber polymer.

Abstract This paper presents experimental investigation on optimizing polyvinyl alcohol (PVA) fiber dosage in engineered cementitious composites (ECC) designed for M-30 and M-40 concrete grades. The study examined workability, compressive, tensile, flexural, shear, and impact strengths across ECC mixes with different PVA fiber contents varying from 0 to 2.5 % by volume with an interval of 0.5 %. Increase in PVA fiber content reduces the workability and is mainly due to fiber entanglement and increased internal friction within the mix. Addition of PVA fiber improves all the mechanical properties up to an optimal content of 1.5 % by volume. At this optimal dosage, compressive, flexural, split tensile and shear strength increased by 3.9 & 4.5 %, 94.2 & 109.5 %, 91.6 & 98.9 %, 140.9 & 157.7 % for M-30 and M-40 grade concrete respectively. Impact strength results showed that number of blows for final failure increased by 174 & 165 times for M-30 & M-40 grades respectively compared to control mix. Results indicate that addition of fiber improves mechanical properties significantly up to an optimal dosage of 1.5 % by volume, beyond which workability decreases and strength gains remains same or slightly decrease due to fiber clustering.

Abstract Stress concentration factors (SCFs) play a critical role in the structural integrity of engineering structures. Rivets, the commonly used joining components, usually leave geometric discontinuities footprints in the form of countersunk holes. The present study investigates the SCF in orthotropic carbon/epoxy (AS4/3501-6) plates with centrally located countersunk holes under uniaxial tensile loading. A comprehensive 3D finite element analysis (FEA) is employed to evaluate the effects of geometric parameters – such as hole radius-to-plate width ratio ( r / w ), plate thickness-to-hole radius ratio ( t / r ), countersinking depth-to-thickness ratio ( C s / t ), and countersink angle ( θ c ) – as well as material orthotropy, represented by the ply angle ( θ p ) and the corresponding infinite plate orthotropic stress concentration factor ( K ∞ ). An artificial neural network (ANN) optimization process is executed to model the relationship between these parameters and the SCF, achieving high accuracy with a root mean square error (RMSE) of 0.0090. The optimal ANN architecture utilizes a single hidden layer with nine neurons, the Levenburg-Marquardt learning algorithm, and a hyperbolic tangent sigmoid activation function. The model is validated against FEA results, demonstrating excellent agreement with errors below 6 % for 94 % of the cases studied. Furthermore, an optimization analysis identifies the geometric and material configuration that minimizes the SCF, yielding a value of ( K t = 1.95) for a plate with ( r / w = 0.1), ( t / r = 5), ( C s / t = 0.1), ( θ c = 80°), and ( θ p = 50°, K ∞ = 1.90). The findings of this work provide valuable insights for designing orthotropic plates with reduced stress concentrations, enhancing their performance and structural integrity.