Purpose This study aims to investigate the effect of bionic crescent-shaped directional micro-textures on bearing surfaces to mitigate premature wear and catastrophic failure under starved lubrication conditions. Design/methodology/approach A coupled thermo-mechanical finite element model was developed to analyze the effects of key texture parameter – texture width (B), inter-texture spacing (M), transverse pitch (L), inclination angle (?) and texture length (W) – on bearing deformation, equivalent stress distribution and temperature fields. Furthermore, a Generalized Regression Neural Network (GRNN) surrogate model was constructed and integrated with the Non-dominated Sorting Genetic Algorithm II (NSGA-II) for multi-objective optimization of texture geometric parameters. Findings Under static loading, texture width (B) and transverse pitch (L) exerted significant influences on stress distribution; specifically, B = 0.1 mm increased the maximum equivalent stress by 27.4% compared with the untextured bearing. Under thermo-mechanical coupling, increasing L from 1 mm to 1.2 mm raised the maximum temperature from 47.98 °C to 72.43 °C and the maximum equivalent stress from 51.15 MPa to 94.68 MPa. The GRNN model predicted equivalent stress and temperature with high accuracy [R2 = 0.98, mean squared error (MSE) = 0.17; R2 = 0.99, MSE = 1.06]. Finite element simulations validated the optimized texture parameters, with relative errors being constrained within 6%, which effectively alleviates stress concentration and high-temperature zones. Originality/value The integrated GRNN-NSGA-II framework offers a novel computational approach for optimizing micro-texture parameters, enabling precise regulation of lubrication performance under suitable texture parameter ranges without extensive experimental testing.
Purpose This comprehensive review synthesizes the current knowledge on advanced seismic retrofitting techniques for existing reinforced concrete (RC) buildings, addressing the critical need to upgrade vulnerable infrastructure in seismically active regions. This study aims to evaluate seven major retrofitting approaches, providing evidence-based guidance for practitioners and researchers. Design/methodology/approach A systematic review was conducted encompassing experimental studies, numerical analyses, case studies and real-world examples. This review examines fiber-reinforced polymer (FRP) wrapping, steel jacketing, concrete jacketing, base isolation energy dissipation devices, shear walls and bracing systems. Performance metrics, applicability criteria, design parameters and economic considerations were developed through experimental validation and real-world implementation. Findings FRP wrapping demonstrates exceptional versatility for member-level strengthening, achieving up to 98% improvement in collapse margins by providing additional strength to the structure. Base isolation provides superior performance with 50%–85% drift reduction and 4–5 × safety improvements, although at a higher initial cost. Energy dissipation devices offer targeted supplemental damping (30%–60% drift reduction) with replaceability advantages. Steel and concrete jacketing remain effective for strength enhancement (30%–80% and 20%–45%, respectively), whereas shear walls and bracing systems provide additional system-level stiffness. The technique selection depends critically on the building characteristics, deficiency types, occupancy constraints and economic factors. Recent studies have included FRP anchoring systems for access-constrained joints, box-section metallic dampers with stable hysteresis and hybrid approaches. Originality/value This review provides a comprehensive synthesis of performance metrics, design parameters, codal provisions and economic considerations across all major retrofitting techniques. The novel contributions of this study include: integrated comparative analysis across seven retrofitting approaches covering advances from 2015 to 2024; evidence-based applicability matrices for technique selection across diverse building characteristics; identification of critical code gaps and standardization needs; comparative cost–benefit analysis integrating lifecycle considerations; and expanded future research directions on sustainability, resilience-based design and long-term durability, which are insufficiently addressed in prior reviews.
Purpose This study aims to investigate the effect of varying proportions of lime (L), gypsum powder (P) and pozzolan (Z) on the mechanical properties and microstructural characteristics of lime-based sand concrete. It also seeks to optimize the composition of the ternary binder using a mixture design methodology and to model the relationships between binder components and the resulting mechanical responses. Design/methodology/approach An experimental program was conducted using a mixture design methodology to systematically vary the relative proportions of lime, gypsum and pozzolan within the ternary binder system. The effects of the component proportions were evaluated in terms of compressive strength (Rc) and flexural strength (Rf) after 7 and 28 days of curing. Statistical models were developed to predict the mechanical responses. In addition, microstructural analyses, including X-ray diffraction (XRD) and optical microscopy, were performed to relate mechanical performance with hydration products and internal structure. Findings The results revealed that gypsum powder content (P) was the most influential factor affecting both compressive and flexural strengths. Among the tested mixtures, SC21, containing 0% L, 10% P and 0% Z and corresponding to a complete replacement of the lime-substitution fraction by gypsum, showed the best mechanical performance, with a 107% increase in compressive strength compared with the reference mix. Microstructural analyses showed that variations in binder composition influenced the nature and distribution of hydration products, which in turn affected the mechanical properties. The studied composites exhibited a relatively dense and homogeneous microstructure with good paste–aggregate bonding. Originality/value This study makes a novel contribution by investigating the lime-gypsum-pozzolan (L–P–Z) ternary binder system for sand concrete, which remains underexplored. In contrast to previous studies mainly focused on mortars or conventional concrete, this work examines how the specific characteristics of sand concrete influence binder reactions, microstructural development and mechanical performance. The combination of mixture design, mechanical testing and microstructural analysis enables the optimization of the binder composition and contributes to the development of improved lime-based sand concrete formulations.
Purpose This work involves the computational analysis of two-dimensional heat transfer through convection and laminar flow of a fluid. The application was conducted on a circular pipe with fully developed laminar flow, taking into consideration boundary conditions such as the wall’s uniform temperature and constant heat flux. Design/methodology/approach The physical characteristics of this flow are assumed to be constant and of an incompressible and Newtonian type. The governing equations describing fluid flow, namely, energy, as well as simplifying assumptions and their associated boundary conditions, have been presented in detail. Equations that govern the studied phenomenon are non-linear partial differential equations (PDEs). Therefore, the authors implemented the finite-difference scheme to integrate these equations through iterations. This involves transforming the equations into a linear algebraic system. Findings For this purpose, FORTRAN computer code has been developed to effectively simulate thermal problems in circular pipes and obtain the results for both cases. This allowed for the evaluation of thermal transfer rates, observation of velocity and temperature contours and determination of the distribution of Nusselt numbers, both local and average. In addition, various factors that influence thermal behavior were identified. The development of this code has provided a comprehensive tool for studying thermal behavior in circular pipes. Finally, the authors conducted a comparative analysis for validation, and the results showed excellent agreement with previous studies. Originality/value The innovation of using an explicit finite difference method (FDM) in FORTRAN to solve the problem centers on computationally tracking the development of the thermal boundary layer without relying on complex, slowly converging infinite series of eigenvalues. An FDM model bypasses this by smoothly moving down the grid to yield localized temperature and heat flux distributions. The innovation involves translating the parabolic PDE into an explicit code. This is achieved by applying the stability condition and an algorithm that easily integrates the nonlinear boundary conditions, resulting in a numerical solution that can be quickly obtained.
Purpose The purpose of this study is to investigate hybrid polymer composites reinforced with shape memory alloy (SMA) wires, as they are promising materials for structural applications combining load-bearing capability with adaptive functionality. Design/methodology/approach In this research, multicomponent-reinforced hybrid NiTi–epoxy composites were produced through a hand layup method using Nitinol wires. The authors studied two wire diameters (0.5 and 1 mm) and three reinforcement configurations comprising one, two and three parallel wires. To obtain stress–strain responses and derive elastic properties, quasi-static tensile tests were performed. Statistical validation involved coefficient of variation, analysis of variance (analysis of variance, α = 0.05) and uncertainty analysis. The experiments were simulated using a finite element model in LS-DYNA with a calibrated martensitic SMA constitutive model. Findings The obtained results indicate that tensile strength and stiffness increase with increasing wire diameter as well as the number of reinforcement layers. The best performance was achieved with the three 1-mm wire configuration, which showed increases of 30.47 MPa and 5.15 GPa in tensile strength and Young’s modulus, respectively. Numerical predictions were consistent with experimental results in an average deviation of 5.6%. The results indicate that an increase in reinforcement layers improves orthotropic stiffness, while larger fiber inclination angles decrease load-bearing efficiency, presenting reliable design guidance for advanced NiTi-reinforced smart composite structures. Originality/value Unlike previous studies that primarily focus on short SMA fibers or lack statistical validation, this work systematically quantifies the combined effects of continuous wire diameter and reinforcement count on the mechanical performance.
Purpose Continuous fiber-reinforced polymer or ceramic matrix composites are advanced materials and have been widely used and developed rapidly in the aerospace and automotive industries. However, their excellent mechanical performance causes severe tool wear and poor machining quality, bringing great challenges to machining. The purpose of this article is to reveal the processing characteristics and commonalities of fiber composite materials processed by ultrafast laser through material comparison research. Design/methodology/approach Femtosecond laser is a special precision machining technique with significant demand in the aerospace field. This paper carried out a green-light femtosecond laser grooving for four different composites. In particular, the machining feasibility and behavior for homogeneous SiC, SiCf/SiC, Cf/SiC and Carbon Fiber Reinforced Polymer/Plastic (CFRP) composites were studied and compared, including grooving depth, ablation rate, taper angle and ablation threshold. Materials’ thermal properties like evaporation enthalpy and thermal conductivity combined with their structural interfacial thermal resistance were found to be the main factors determining their processing performance. Findings Results showed that, by the machining ability and efficiency increasing order or decreasing order of ablation thresholds, they were ranked as follows: SiC, SiCf/SiC, Cf/SiC and CFRP. Proportionally increasing pulse frequency and grooving speed, slight variations of the groove width, grooving depth, ablation rate, heat-affected zone and groove taper angle were obtained. Originality/value Thus, the analyzed machining method provided high-speed grooving that improved processing efficiency without deteriorating processing quality.
Purpose This study aims to systematically review the use of time-series predictive analytics in the mining industry, highlighting its role in anticipating critical operational, environmental and geotechnical events through data obtained from sensors, telemetry and remote monitoring technologies. Design/methodology/approach A mixed-methods approach was used, combining bibliometric analysis, text mining and qualitative content synthesis. The review followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 protocol to select 135 peer-reviewed articles published between 1968 and 2025, complemented by an ad hoc search to ensure comprehensiveness. The analysis encompassed both traditional statistical forecasting models and contemporary machine learning (ML) and deep learning (DL) techniques. Findings The review reveals a marked increase in research activity since 2022 and identifies two main thematic clusters: (i) operational applications of time series forecasting in underground and open-pit mining, focusing on processes such as haulage, drilling/blasting, ventilation and geotechnical stability; and (ii) ML/DL-based forecasting models, particularly sequential (LSTM/gated recurrent unit (GRU)), attention-based (transformers) and hybrid architectures. Key challenges identified include model transferability, external validation and uncertainty quantification. The study proposes four future research directions to enhance the robustness, interpretability and practical applicability of forecasting models in real-world mining scenarios. Originality/value This study offers the first integrated review of time-series forecasting in mining, combining bibliometric mapping and thematic synthesis from 1968 to 2025. It highlights how traditional and ML/DL models are applied to key mining operations and identifies gaps in model transferability, validation and uncertainty. The findings provide actionable insights for improving predictive analytics in real-world mining contexts.
Purpose The novelty of this research is to investigate the heat transfer characteristics of ternary hybrid nanofluid (NF) flow within a porous medium affected by a magnetic field over a stretching sheet. The distinctive aspect of the work lies in examining the combined effects of thermal radiation, the Cattaneo-Christov heat flux model, suction/injection and the Biot number on the transport phenomena of ternary hybrid NFs.Design/methodology/approach The appropriate similarity transformations are applied to reduce the governing partial differential equations (PDEs) into a system of ordinary differential equations. The study further explores the applicability of soft computing approaches in predicting the complex behavior of the system influenced by multiple interacting parameters, including magnetic field, surface suction/injection, thermal radiation, Biot number, nonuniform heat source/sink and porous medium effects. To handle the resultant nonlinear system numerically, the "bvp4c function" in MATLAB is used. After that, an artificial neural network (ANN) and a fuzzy particle swarm optimization (FPSO) technique are used to estimate the Nusselt number values at the stretched sheet with accuracy.Findings Furthermore, it is seen that when the radiation parameter (Rd) varies from 0.1 to 2, the heat transfer rate rises by 203.84% and 226.76% for suction parameters S = 1.1 and S = 1.5, respectively. The conclusion highlights the potential of ANN and FPSO algorithms in heat transfer assessments by showing that they provide efficient solutions for physical issues.Originality/value The present research extends its scope to examine the effectiveness of soft computing techniques in analyzing fluid flow models that involve heat transfer phenomena.
Purpose This study aims to provide a comprehensive evaluation of the potential of ionic liquids (ILs) as green alternatives to conventional catalysts and solvents in biodiesel production. It highlights the need for sustainable, low-impact processes that overcome the environmental and energy-intensive limitations of traditional biodiesel synthesis routes. Design/methodology/approach This review systematically examines recent literature on the application of ILs in biodiesel production, focusing on their catalytic mechanisms, extraction efficiency and process optimization. Emphasis is placed on comparing the performance of ILs with that of conventional acid and base catalysts, assessing their reusability, stability and influence on reaction kinetics and yields. Findings It was revealed that ILs exhibit tunable physicochemical properties and impressive solvent versatility, enabling enhanced conversion efficiency and product purity in biodiesel synthesis. They significantly reduce by-product formation and energy consumption while offering potential recyclability. Nonetheless, challenges such as high production cost, toxicity of certain ILs and limited large-scale application remain key barriers to commercialization. Originality/value This review consolidates recent advances in the integration of ILs into biodiesel production and provides a critical perspective on their environmental and economic implications. It offers an updated framework for understanding how IL-based catalytic systems can drive the transition toward more sustainable and circular biofuel production technologies.
PurposeThe purpose of this study is to review the regeneration of metal components from the cathode of spent lithium-ion batteries (LIBs) using food wastes. Design/methodology/approachThis review critically explored the use of common food wastes like orange peels (OPs), waste tea, macadamia shells and grape seed waste in regenerating the metal components from the cathodes of expended LIBs that have been pretreated. Additionally, this study explores the economic viability of using food waste for LIB recycling and the outlook for this innovative approach. FindingsThe reductive potentials of certain food wastes: OPs, waste tea, macadamia shells and grape seed, were evaluated for their abilities to leach metal components from the cathodes of spent LIBs. OP yielded 80%–99% leaching of the important metals: Li, Co, Ni and Mn. Waste tea yielded leaching efficiencies of almost 100% for Ni, Li and Mn and about 90% for Co. Macadamia shell yielded 93.4% leaching of lithium. Grape seed showed that the efficiencies of 99% and 92% could be achieved for Li and Co, respectively. Research limitations/implicationsThis research/method suffers from variabilities in food composition, with amount of extractable useful components differing greatly among different food wastes. Also, the seasonal availability of some foods is also a critical concern. With these limitations, there comes a challenge regarding the scalability of this method. Originality/valueThis paper presents an original comprehensive review of the regeneration of metal components from the cathode of spent LIBs using food wastes.
PurposeThis review provides a comprehensive assessment of the machining challenges associated with carbon fiber reinforced polymers (CFRP) and glass fiber reinforced polymers (GFRP) composites, which are widely used in high-performance structural applications due to their excellent strength-to-weight ratio, corrosion resistance and the ability to be tailored in specific ways. Nevertheless, their multilayered and anisotropic nature adds considerable complexity to the machining process, often leading to defects. This paper aims to give key insight into machining issues, focusing on parameter-response relationships that govern surface quality and defect formation. Design/methodology/approachThe literature survey covered a broad range of machining methods, including conventional machining methods such as CNC drilling and milling, as well as nonconventional methods such as abrasive waterjet machining, ultrasonic machining and laser cutting. For the traditional methods, the influences of feed rate, cutting speed, depth of cut, tool geometry, tool material and coolant use were studied. In nonconventional machining, several crucial factors, including jet pressure, abrasive characteristics, laser power and thermal interaction, were taken into account. Specific attention was given to machining-induced defects, i.e. delamination, fiber pull-out and matrix cracking, tool wear, kerf taper, heat-affected zones and surface degradation because they depend on the process parameters and identify potential damage-reduction methods. FindingsThe machining behavior of CFRP/GFRP composites depends strongly on tool geometry, thermal load and parameter selection. Optimized drilling parameters, such as 70–90 m/min cutting speed, 0.01–0.05 mm/rev feed rate, multifacet carbide/polycrystalline diamond coated drill bit with 45-degree helix angle, can minimize thrust force, delamination, fiber pull-out and other machining flaws. The milling operation with 100–200 m/min cutting speed for carbide tool, 0.02–0.1 mm/rev feed rate and 0.1–1.0 mm depth of cut controls machining damage like fiber fraying, delamination and also increases machining efficiency. Abrasive water jet machining (AWJM) has a high success rate in cutting carbon and glass-epoxy composites. AWJM performs effectively at 200–350 MPa pressure, 1–3 mm stand-off distance, 80–120 mesh garnet abrasive particles and <200 mm/min cutting speed, yielding low kerf taper and minimal fiber breakout. Ultrasonic machine achieves precise material removal with 20–40 kHz frequency, 5–15 µm amplitude, 0.1–0.3 MPa pressure, 0.1–0.5 mm/min feed rate and 5–10 L/min slurry flow provides minimal subsurface damage in composite laminate. Laser machining provides precision, noncontact ablation using 50–300 W power, 20–50 kHz frequency, 10–50 ns pulses and inert assist gases, effectively constraining HAZ formation and preserving fiber–matrix integrity. Better parameter selection, including adaptive solutions and combined machining strategies, can prolong tool life, reduce defects and improve surface integrity. Originality/valueThis paper presents a critical and consolidated study of machining techniques for CFRP and GFRP composite materials, suggesting parameters that can serve as a bridge between conventional and nonconventional machining methods. These results can be used to establish defect-mitigation techniques, improve machinability and inform future research in manufacturing composites.
PurposeThis study aims to investigate the influence of post-ageing cooling media on the microstructure, mechanical properties, surface roughness after turning and fracture behaviour of AA6063 aluminium alloy subjected to a two-stage heat treatment cycle consisting of solutionising at 500 degrees C for 2 h followed by water quenching and artificial ageing at 200 degrees C for 5 h.Design/methodology/approachSix cylindrical AA6063 specimens, including one as-received sample, were heat treated under identical conditions and subsequently cooled using five different post-ageing media: air, oil, furnace, sand and water. Optical microscopy was used for microstructural observation, while hardness testing, tensile testing, surface roughness measurements after turning and field emission scanning electron microscopy-based fractographic analysis were conducted to evaluate the effect of different cooling paths.FindingsDistinct differences in mechanical response and surface finish were observed among the cooling conditions. Faster post-ageing cooling media (water and oil) exhibited higher hardness values (approximate to 88-89 HRB), whereas furnace cooling resulted in lower hardness (approximate to 75 HRB) and increased ductility (elongation approximate to 23.4%). Tensile strength was higher for water and sand cooled specimens (UTS approximate to 206-207 MPa) compared to furnace-cooled specimens (approximate to 153 MPa). Surface roughness after turning varied significantly with cooling medium, with sand-cooled samples producing the smoothest surface (Ra approximate to 2.9 & micro;m) and air-cooled samples exhibiting the highest roughness (Ra approximate to 5.6 & micro;m) under identical machining conditions. Optical microstructural features and mechanical trends were consistent with literature-reported cooling rate-dependent precipitation behaviour in Al-Mg-Si alloys. Fractographic analysis revealed ductile fracture dominated by microvoid coalescence across all conditions.Originality/valueUnlike conventional studies focusing on T5/T6 temper comparisons or ageing parameters, this work isolates post-ageing cooling medium as the primary variable and demonstrates its significant role in tailoring the strength-ductility balance and surface finish of AA6063 alloy. The findings highlight post-ageing cooling as a simple yet effective heat treatment parameter for optimising mechanical performance and machinability in practical engineering applications.
PurposeThis study aims to propose a novel dual-nozzle fused deposition modeling (FDM) approach in which a secondary nozzle is used to fill interfilament air gaps using either the same material (thermoplastic polyurethane [TPU-TPU]) for the single-material case or a different, compatible material (TPU-PLA, TPU-ASA and TPU-ABS) for multimaterial cases. The objective is to mitigate the adverse effects of the inherent layered structure of FDM-printed parts, which introduces voids between filaments and layers, increases porosity and reduces mechanical strength.Design/methodology/approachThe effectiveness of both single- and multimaterial gap-filling strategies is evaluated in terms of stiffness and strength. Classical Laminate Theory (CLT) is used to assess the elastic behavior, while finite element analysis (FEA) of a representative volume element (RVE), using Dirichlet boundary conditions, is conducted to evaluate the elastic-plastic response. For the single-material case, air gaps between TPU filaments are filled with the same material (TPU). For the multimaterial case, the gaps between TPU filaments are filled with compatible secondary materials (PLA, ASA and ABS). In the composite formulations, TPU is treated as the matrix, while PLA, ASA and ABS are considered reinforcing fibers.FindingsThe predicted results indicate a significant reduction in porosity, decreasing from approximately 11% to 4% for a 0.4 mm layer height case. In addition, we found that, As the layer height increases, the porosity percentage remains substantially lower than that of the no-filling baseline case regardless of the printing materials. For example, at a 0.8 mm layer height, porosity is reduced from approximately 21.5% to 8%. This behavior counteracts the typically adverse effects of increasing layer height, where larger voids are expected; in contrast, the proposed gap-filling technique utilizes the increased gap size to accommodate larger gap-filling filaments. The proposed approach also demonstrates strong potential for improving mechanical properties due to porosity reduction. For single-material gap-filling, stiffness is predicted to increase by approximately 18% in the transverse direction (normal to printing direction), 155% in the longitudinal direction (aligned with printing direction) and 119% in shear modulus. For multimaterial gap-filling, where stiffer materials are used as fillers and deposited simultaneously with TPU, stiffness along the fiber direction increases from 12.73 MPa to 134.6 MPa, 95.8 MPa and 103.59 MPa when using PLA, ASA and ABS, respectively. This results in intermediate part stiffness, which can be useful in many industrial and medical applications such as snap-fit components, seals and joints. In terms of strength, gap-filling with PLA filaments improves tensile strength along the fiber direction by approximately 90%, compressive strength by around 70% and shear strength by up to 57% along the 90 degrees plane compared to the no-filling case. When comparing gap-filling with the same material (TPU) versus different materials (PLA, ASA and ABS), the improvement in tensile strength along the fiber direction reaches 43.6%, 40.3% and 40.3%, respectively. At the ply scale, strength enhancements reach approximately 190% for bidirectional configurations and 230% for unidirectional layouts at a 0.4 mm layer height case. The reported results show how implementing higher material strength to fill air gaps of FDM-printed elastic material such as TPU can increase part strength and leads to outstanding part mechanical properties. The effect of printing direction is also investigated, revealing a tradeoff between stiffness and anisotropy, with a 0 / 90/90 / 0 ply orientation identified as optimal for in-plane stiffness.Originality/valueThis work demonstrates, through theoretical and numerical modeling, the potential of a dual-nozzle gap-filling strategy to significantly improve the mechanical performance of FDM-printed parts by reducing porosity and enhancing both stiffness and strength. This work intentionally focuses on mechanical feasibility and design potential.
Purpose The purpose of this study is to experimentally investigate and compare the tribological performance of a textolite-steel gear pair with a conventional steel-steel pair under rolling-sliding contact conditions representative of textile machinery. Gear transmissions are essential components of textile machinery, where friction and wear significantly influence durability, energy efficiency and operational reliability. Conventional steel gears operating under boundary and mixed lubrication conditions are prone to adhesive and abrasive wear, particularly in dust-laden environments. Polymer-based composite materials have emerged as promising alternatives due to their lower elastic modulus, improved damping capacity and favorable tribological behavior.Design/methodology/approach This study experimentally compares the tribological performance of a textolite-steel gear pair with that of a conventional steel-steel pair under rolling-sliding contact conditions representative of textile machinery. Tests were conducted under normal loads of 100-400 N and sliding velocities of 0.5-1.5 m s-& sup1;, with sliding distances up to 5400 m, under dry contact conditions as a conservative baseline. The friction coefficient, volumetric wear rate, contact temperature rise and transfer-film formation were quantitatively evaluated. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses were performed to characterize worn surface morphology and transfer-film composition.Findings The textolite-steel pair exhibited a 35%-50% lower steady-state friction coefficient (& micro; = 0.04-0.07) compared with the steel-steel pair (& micro; = 0.08-0.12). Wear rates were reduced by a factor of two to four (W = 0.8-2.0 & times; 10-6 mm & sup3; N-& sup1; m-& sup1; versus 3.0-6.0 & times; 10-6 mm & sup3; N-& sup1; m-& sup1;), and friction-induced temperature rise decreased from 22 degrees C-35 degrees C to 10-20 degrees C. SEM/EDS analysis confirmed the formation of a carbon- and oxygen-enriched polymer transfer film (C: 12.3 wt.%, O: 4.2 wt.%) on the steel counterface.Originality/value The improved tribological performance is attributed to three coupled mechanisms: elastic compliance, interfacial stress redistribution and stable polymer transfer-film formation. SEM and EDS evidence directly substantiates the proposed transfer-film mechanism. These findings provide an experimentally grounded framework for improving the durability and energy efficiency of composite gear systems in textile machinery. The study is conducted under dry contact conditions; the influence of lubrication on the observed mechanisms is identified as a direction for future investigation.
Purpose- This study aims to optimize the physical design parameters of the front interface in (p-i(1)-i(2)-n)a-Si:H thin-film solar cells. The research focuses on identifying the optimal combination of acceptor doping concentration (N-A), bandgap (E-g) and p-layer thickness (d(p)) under varying front contact barrier potentials ( phi(b0 )phi(b0)), which are independently examined through a parametric analysis to maximize conversion efficiency. Design/methodology/approach- The research uses an integrated framework combining numerical simulation via Automat for Simulation of Heterostructures (AFORS-HET) with the Taguchi statistical Design of Experiments. A Taguchi L9 orthogonal array was used to systematically explore parameter interactions with minimal simulation runs. Main Effect Analysis and Analysis of Variance were subsequently applied to evaluate the sensitivity and contribution of each parameter to the cell's efficiency. Findings- The results identify N-A as the most dominant factor, contributing 78.27% to the variation in efficiency, followed by d(p) (16.80%) and E-g (3.01%). The optimal configuration (N-A = 1.0 & times; 10(19) cm(-3), E-g at 1.85 eV and d(p) at 9 nm) yielded a confirmed conversion efficiency of 9.82%. The study demonstrates that coupling numerical modeling with Taguchi-based optimization significantly enhances computational efficiency. Originality/value- This work presents a systematic integration of AFORS-HET with a Taguchi statistical framework, combined with a parametric evaluation of front contact barrier potentials, to investigate performance optimization in (p-i(1)-i(2)-n)a-Si:H structures. This physics-informed framework provides a cost-effective and adaptable methodology for developing high-performance next-generation photovoltaic technologies.
Purpose This study aims to investigate the elastic hoop stress response of pressurized steel pipelines containing full-circumference longitudinal corrosion defects, with an emphasis on stress amplification, axial redistribution and the spatial extent of the disturbed region.Design/methodology/approach A three-dimensional finite element model of a straight pipeline segment subjected to internal pressure was developed. The corrosion defect was idealized as a region with uniform wall thinning. A parametric analysis was conducted for six normalized defect lengths (Ld/D = 0.05 - 2) and four depth ratios (a/t = 0.1 - 0.4). Inner- and outer-surface hoop stresses were extracted to evaluate the axial stress distribution, peak stress, stress concentration factors and recovery length based on the defined tolerance limits.Findings The defect depth governs the magnitude of stress amplification, whereas the defect length mainly controls whether the peak stress becomes fully developed. The maximum inner-surface stress reached 156.8 MPa (1.65 times the intact value), whereas the outer-surface stress increased to 108 MPa (1.27 times the intact value). Peak stresses became insensitive to defect length beyond Ld/D approximate to 0.5 at the inner surface and Ld/D approximate to 0.25 at the outer surface. The axial disturbance was strongly localized, with the hoop stress recovering within approximately 0.09-0.16D at the inner surface and 0.04-0.08D at the outer surface based on a 5% tolerance .Originality/value This study provides a mechanics-based characterization of elastic stress amplification and localization associated with longitudinal wall thinning under service-level loading.
Purpose This paper aims to propose a novel dielectric-modulated dual-cavity organic thin-film transistor (DMDCOTFT) biosensor enabling label-free, high-precision biomolecule detection with reduced sample preparation complexity, targeting medical diagnostics and environmental monitoring.Design/methodology/approach The proposed DM-DC-OTFT biosensor uses the dual cavities embedded in the gate dielectric near the source and drain regions to enhance dielectric modulation and electrostatic control. Device performance is analyzed using TCAD simulation by solving the coupled Poisson and carrier continuity equations on a finite mesh. Biomolecule detection is modeled by replacing the air-filled cavity (k = 1) with materials of varying dielectric constants and assigned charge densities representing neutral and charged species.Findings The drain current sensitivity for HfO2 and Al2O3 rises by 458.86% and 315% for neutral biomolecules and by 116% and 62.42% for negatively charged biomolecules at VDS = -1.5V and VGS = -3.0V with K = 12. The device attains a maximum sensitivity of 8.76 & times; 104 for HfO2 and 4.4 & times; 104 for Al2O3 at VGS = -1.3V for rho = -1 & times; 10 & sup1;& sup2; cm-2.Originality/value A reference air-filled cavity (k = 1) is adopted as the standard for sensitivity evaluation to resolve inconsistencies in prior organic biosensor studies, while the proposed label-free dual-cavity design improves sensitivity and detection reliability.
Purpose This paper aims to deliver accurate and robust parameter identification for proton exchange membrane fuel cells (PEMFCs) by enhancing the gorilla troops optimizer (GTO) with physics-consistent search mechanisms and evaluation-aware control.Design/methodology/approach We propose an improved GTO (IGTO) tailored to PEMFC polarization modeling. The identification problem is formulated as the minimization of the discrepancy between measured and model-predicted voltage-current characteristics, using a weighted sum of squared errors (SSE) objective with an optional Huber loss and light ridge regularization. IGTO integrates (i) vector (parameter-wise) bounds aligned with PEMFC physics, (ii) adaptive schedules for the main control parameters to coordinate exploration and exploitation, (iii) explicit elitism to preserve the best solution, (iv) opposition-based restart with jitter to mitigate stagnation and (v) early stopping under objective stabilization. The method is validated on three commercial PEMFC stacks (Horizon 500 W, BCS 500 W and NedStack PS6) and benchmarked against baseline GTO and representative metaheuristics under matched settings.Findings Across all stacks, IGTO achieves lower identification errors and improved stability over R = 30 independent runs. The best obtained SSE values are 2.06435 (NedStack PS6), 1.114 imes 10-2 (BCS 500 W) and 1.102 imes 10-2 (Horizon 500 W), with consistently faster convergence and reduced run-to-run dispersion compared with the baseline.Practical implications The method enables routine, reliable PEMFC parameter tuning for diagnostics, control and digital-twin applications, shortening calibration time and reducing computational cost.Social implications More accurate fuel-cell models support higher efficiency, reliability and lifetime, contributing to cleaner energy systems and reduced emissions.Originality/value IGTO provides a coherent, PEMFC-driven enhancement of GTO that couples physics-aligned vector bounds, robust identification objectives and evaluation-aware search control (adaptive schedules, elitism, restart and early stopping), enabling reliable parameter extraction in a practical MATLAB workflow.
Purpose Advancing next-generation energy storage technologies requires electrode materials that provide high performance, sustainability, cost-effectiveness and excellent long-term cycling stability. This study aims to develop and evaluate a bimetallic MgAl2O4/reduced graphene oxide (rGO) composite to overcome the intrinsic limitations of bimetallic oxides, particularly low electronic conductivity and significant volume expansion during charge/discharge processes. Design/methodology/approach A MgAl2O4/rGO nanocomposite was synthesized and systematically optimized to enhance electrochemical performance. Structural, morphological and surface characteristics were examined using X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer Emmett Teller analyses, while thermal stability was assessed via thermogravimetric analysis. Electrochemical performance was evaluated in a KOH electrolyte using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. Findings The composite displayed a well-defined phase structure, high surface area and good thermal stability. Cyclic voltammetry results demonstrated strong pseudocapacitive behavior, and galvanostatic charge/discharge measurements showed high energy and power densities with low internal resistance. Electrochemical impedance spectroscopy analysis confirmed improved charge transfer and reduced impedance. The electrode exhibited excellent cycling stability, indicating that the MgAl2O4/rGO composite successfully mitigates conductivity and volume-expansion issues commonly associated with bimetallic oxides. Originality/value This work presents a novel MgAl2O4/rGO bimetallic nanocomposite engineered to enhance conductivity, structural stability and overall electrochemical performance. This study highlights a promising, sustainable and cost-effective electrode material suitable for next-generation high-performance energy storage systems.
Purpose This study aims to investigate the failure mechanisms of SiCf/SiC composite laminates with reinforced installation holes under out-of-plane tensile loading, with the objective of identifying and validating structural design configurations that improve load-bearing capacity.Design/methodology/approach A SiCf/SiC composite laminates sub-element with a reinforced installation hole was tested on universal material testing system, and fracture features were examined by scanning electron microscope and optical microscopy. Then, a progressive damage model based on the Hashin failure criterion and progressive damage was built, which demonstrated a high level of consistency with experiment. Furthermore, parametric studies on ply orientation and reinforced configurations were conducted using the finite element model.Findings Crack initiation occurs in the transition zone and propagates along interlaminar interfaces. Matrix cracking governs the initial damage stage, while SiCf/SiC composite laminates retain partial load-bearing capacity until fiber fracture ensues in the transition zone. The progressive damage model incorporating the Hashin failure criterion and progressive damage accurately predicts damage modes, load-bearing capacity and crack morphology of the sub-elements under out-of-plane loading. The predicted peak load (3478 N) differs by only 10.61% from the experimental peak load (3891 N). Furthermore, increasing 90 degrees plies in the transition zone improves bearing capacity, and reinforced-hole contact geometry significantly affects failure strength.Originality/value This work provides an application-oriented failure and optimization framework for SiCf/SiC nozzle regulating plates, integrating out-of-plane tensile experiment on a representative sub-element with a validated progressive damage model.
