Methodology gaps in Engineering

Representative open questions

Showing 30 of 105 — one per source paper, highest-quality first.

• Basalt powder as a sustainable precursor in alkali‑activated materials: a critical review of performance, mechanisms, and durability (2026) · doi

  The alkali fusion pre-treatment of basalt powder at 450–750 °C increased reaction degree from 8% to 38% and 7-day strength from 2.4 to 12.1 MPa, but the optimal temperature, NaOH ratio, and heating duration have not been systematically optimized. Additionally, the scalability and economic feasibility of alkali fusion as an industrial pre-treatment method for BP in alkali-activated materials requires investigation.

• Sophisticated control design for direct drive permanent magnet synchronous generator-based wind turbines under voltage sags (2026) · doi

  The paper acknowledges that dedicated devices and strategies are recommended for longer voltage sag events but does not specify what these strategies are or how they should be integrated with the proposed control design methodology for PMSG-based wind turbines operating under sustained low-voltage conditions.

• Experimental evaluation of bond performance between substrate and overlay concrete using bonding agents and mechanical connectors (2026) · doi

  The paper attributes minor discrepancies in fracture propagation patterns to intrinsic material heterogeneity and localized interface properties, but does not systematically investigate how concrete porosity, aggregate size distribution, or local interface defects at the substrate-overlay boundary affect bond strength variability across replicated specimens.

• Metal repair using hybrid additive manufacturing process: A comparative study of interfacial surface roughness for improved mechanical strength (2026) · doi

  The FE model is limited to interpreting mechanical responses of repaired components and cannot identify optimal surface roughness values for hybrid additive manufacturing repair. Future work must develop physics-based microstructural models that incorporate interfacial roughness parameters to determine the specific roughness range (between the tested 8.76 μm and 91.57 μm) that maximizes bonding strength.

• Advancement in fusion welded aluminium alloy joints by friction stir processing technique: a critical review (2026) · doi

  Advanced tool path strategies including overlapping passes, oscillating paths, and gradient processing for large-area or complex weld geometries in fusion-welded aluminium alloys lack experimental validation regarding process repeatability, defect elimination efficiency, and computational modeling frameworks.

• Harnessing Surface Instabilities for Functional Materials: Mechanics, Morphology, and Emerging Applications (2026) · doi

  Wettability patterning in microfluidic devices using thermally-enhanced hydrophobic recovery of PDMS has been demonstrated, but the precise control parameters for generating complex wrinkling patterns with predictable contact angle gradients and their stability over extended operation times remain to be systematized.

• Advances of artificial intelligence applications to low-carbon metallurgy of iron and steel (2026) · doi

  The burn-through point prediction in iron ore sintering has been modeled using fuzzy time series approaches, but integration of these soft-sensing models with weighted kernel just-in-time learning for real-time adaptive prediction across varying ore compositions and operating conditions needs systematic investigation.

• Design Optimization of an Additively Manufactured Passive Vibration Isolator for an Inertial Measurement Unit for Enhanced Measurement Performance (2026) · doi

  The nonlinear finite element analysis assumes isotropic material properties for PLA and aluminum components; however, additive manufacturing introduces anisotropy and directional mechanical property variations depending on print orientation and infill parameters (Table 6 lists infill parameters but analysis does not account for print direction effects).

• Physics-Informed Symbolic Regression Ensemble (PISRE) for surface roughness prediction in Ti-6Al-4V dry turning (2026) · doi

  The physics-informed constraints embedded in Branches A and C (e.g., Rath, Achip, ln(1 + Rath)) are derived from established Ti-6Al-4V cutting mechanics but no comparison is provided between PISRE-NF and alternative physics-derived feature sets or Bayesian optimization of the constraint set across different material classes.

• Evaluating interior lighting as an indoor environmental quality component using virtual reality (2026) · doi

  The interaction effects between lighting parameters (illuminance levels, correlated color temperature, luminance distribution) and other indoor environmental quality factors (thermal comfort, acoustics) have been identified as an emerging research trajectory, but systematic VR-based experimental designs isolating and measuring these interaction effects remain underdeveloped.

• Improving Low-Vision Chart Accessibility via On-Cursor Visual Context (2026) · doi

  Dynamic Context exhibited visual element overload while Mini-map's visual elements were too small to perceive for low-vision users. Future work should investigate optimal visual abstraction levels and adaptive sizing mechanisms that maximize visual access to contextual information (axes, legend, grid lines, overview) while reducing cognitive complexity.

• Wind Tunnel Testing for Wind Energy: A State-of-the-Art Review (2026) · doi

  Data-driven methods have been recently applied to extract insights from unsteady wind turbine airfoil loading datasets with high variability, but systematic comparison of different data-driven approaches for characterizing stall cell instability phenomena and their physical mechanisms across multiple thick-airfoil designs remains unexplored.

• Multifunctional zinc-ion capacitors for energy storage (2026) · doi

  No standardized evaluation method exists for zinc-ion capacitor electrodes and prototype cells, making cross-comparison of electrochemical properties difficult across flexible and electrochromic ZIC systems. A comprehensive standardization protocol must specify loading density, active material components, electrode area, and key electrochemical performance parameters.

• Functional nanocomposites for energy storage: chemistry and new horizons (2020) · doi

  Energy density measurement limitations prevent testing at high nanoparticle volume fractions due to reduced breakdown strength; a non-destructive method or predictive model to estimate maximum achievable energy density in polymer nanocomposites without direct electrical breakdown testing is needed.

• Smart Security System and Home Automation System: An IoT-Based Approach Using ESP32 and Voice Integration (2026) · doi

  Relay chattering is mitigated with 100ms software debounce and 10A@250V AC-rated relays, but no systematic analysis of switching frequency limits, inductive load handling, or surge protection strategies is provided for high-power appliances in the 4-channel expansion mentioned for future work.

• Automatic Car Parking System by using ESP 32 (2026) · doi

  The system logic decrements and increments slot counts based on IR sensor detection of vehicle clearance, but does not address edge cases such as simultaneous entry/exit, sensor occlusion by parked vehicles, or recovery mechanisms if slot count synchronization is lost with actual occupancy.

• Revolutionizing infection control in ICUs: photocatalytic binder materials with platinum nanoparticles (2026) · doi

  The durability and sustained antimicrobial efficacy of binder-incorporated platinum nanoparticle materials under repeated cleaning and disinfection protocols in actual healthcare environments remains untested; longitudinal studies simulating ICU operational conditions are needed to validate real-world performance.

• The Basis of a Greener Analytical Chemistry (2011) · doi

  On-line decontamination processes and end-pipe treatments for mechanized methods are identified as critical for handling toxic analytical wastes from metal and pesticide analyses, but the paper provides no specific protocols, efficiency data, or comparisons of different decontamination strategies for different waste types.

• Piezoelectric stepped-plate resonators vibrating at lateral modes for direct viscosity determination in liquids (2026) · doi

  The piezoelectric stepped-plate resonator was tested only in a temperature-controlled laboratory environment. The dynamic viscosity of Newtonian liquids decreases exponentially with temperature, and silicon-based resonators exhibit negative frequency shifts with temperature due to Young's modulus variation. A temperature compensation algorithm needs to be developed and experimentally validated to correct for temperature-induced variations in Young's modulus under ambient (non-controlled) conditions.

• Data-Driven Approaches to Reliability Modeling in Critical Energy Infrastructure: Analytical Perspectives on Early Failure Detection (2026) · doi

  Physics-informed neural networks and hybrid control-learning systems that embed degradation physics, thermodynamic constraints, and governing equations within neural architectures are underdeveloped for early failure detection; integration of domain knowledge with data-driven adaptability to maintain physical consistency and operational credibility remains largely unexplored.

• A review of additive manufacturing techniques for wind turbine blade production: capabilities, AI integration, and Scale-Up Potential (2026) · doi

  Hybrid manufacturing techniques combining subtractive processes with additive manufacturing for wind turbine blade production have not been comprehensively investigated. Development of integrated AM-subtractive hybrid workflows and their scalability to utility-scale blade manufacturing requires systematic research.

• PF-Bearing Analyzer: algorithmic implementation of the peak factor method for diagnosing and predicting the technical condition of rolling bearings (2026) · doi

  L1-regression is employed for remaining useful life prediction to minimize random artifacts in vibration signals; however, the paper provides no comparison with alternative robust regression methods (L∞ regression, Huber regression, quantile regression) or machine learning approaches (support vector regression, LSTM neural networks) to establish which method best handles transient impulses and bearing defect progression nonlinearity.

• Performance Evaluation of Electric Vehicles Using PSO and AHA Based Optimal Control Methodology (2026) · doi

  The paper demonstrates AHA tuning of Proportional-Integral controllers for EV speed tracking but does not investigate whether the AHA strategy generalizes to other control architectures (e.g., PI-based torque control, model predictive control) or different EV powerertrain topologies (battery electric vehicles vs. plug-in hybrid electric vehicles).

• Intelligent performance prediction of nanoparticle-enhanced automotive radiator cooling using CFD and machine learning (2026) · doi

  The Grid Convergence Index (GCI ≈ 0.48%) is reported for CFD discretization uncertainty, but the paper does not specify the turbulence model employed, mesh independence study details, or validation of the nanofluid property correlations (thermal conductivity, viscosity, density) used in the CFD simulations across the 1-5% Al₂O₃ concentration range.

• Statistical fault analysis of Ascon: multiple distinguishers and impossible-state exploitation (2026) · doi

  The paper discusses multi-bit fault injection feasibility via hardware Trojans and multi-spot lasers but does not explore whether simultaneous multi-bit faults targeting multiple S-box outputs across different Ascon rounds could reduce the required number of fault injections below the reported 34.

• AI-driven adaptive vibration control in smart plate systems: a sustainable approach for next-generation sports engineering (2026) · doi

  Material composition optimization is discussed qualitatively for FG-X weight fractions (0.1%-0.4%), but specific design guidelines for selecting optimal material configurations to balance performance and durability in sports plate systems are not provided, limiting practical implementation.

• Electron transfer mechanism in microbial fuel cells (2026) · doi

  MFC sensitivity to operating parameters (temperature, pH, ion species, substrate concentration) has not been systematically quantified for online sensing applications; specific sensitivity thresholds and response curves must be established to enable real-time operational monitoring in wastewater treatment systems.

• Prototyping of self-sustaining propulsion systems for solar system exploration (2026) · doi

  The paper addresses propellant mass ratio optimization to minimize required propellant through multi-stage rocket design, but provides no specific analysis of optimal staging configurations, mass distribution strategies, or structural efficiency factors for self-sustaining propulsion systems operating across multiple solar system destinations.

• Vision-Based Adaptive Traffic Signal System with LoRa Emergency Vehicle Priority (2026) · doi

  The automatic incident detection enhancement mentioned in future work lacks specificity regarding what types of incidents (accidents, stalled vehicles, debris) should be detected or what vision-based features (e.g., trajectory anomalies, vehicle clustering patterns) would distinguish incidents from normal traffic congestion.

• A High-Fidelity Numerical Study of Trans-Laminar Fracture in Carbon/Epoxy Laminates Under Varying Environmental Conditions (2026) · doi

  The numerical framework does not appear to incorporate theory-guided machine learning approaches (referenced in Zobeiry et al., 2020) for characterizing damage evolution in carbon/epoxy laminates under combined hygrothermal and mechanical loading, limiting predictive capability for complex environmental scenarios.