Methodology gaps in Engineering

Representative open questions

Showing 30 of 124 — 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.

• Preg-Robbing in Refractory Gold Ores: A Critical Review of Mineralogical Controls, Pretreatment Strategies and Flowsheet Selection (2026) · doi

  Carbon characteristics (type, reactivity, surface area) are identified as coupled with adsorption severity, but no standardized mineralogical characterization protocol exists to quantitatively predict preg-robbing intensity from ore mineralogy before process selection; development of such predictive tools would reduce reliance on case-by-case testing.

• 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.

• Revisiting the Modification Strategies of Alloy-Base Anode for Solid-State Lithium-Ion Batteries Through Deconstructing Anode-Interface-Solid Electrolyte (2026) · doi

  The ZIF-67 precursor's thermal stability and carbonization process were described qualitatively, but the specific temperature windows (heating rates, duration, inert atmosphere composition) required to achieve optimal nitrogen-doped carbon structure while maintaining inherited high specific surface area and uniform metal distribution in MOF-derived composites for alloy-base anodes have not been systematically mapped.

• Bayesian optimization for uncertainty-aware prediction of rainfall-induced deformation in embankment dams (2026) · doi

  The multiplicative uncertainty-calibrated score (UCS) formulation achieves near-nominal coverage but yields comparatively inferior final UCS values relative to weighted formulations (e.g., 0.7EC + 0.3CRPS). Future work should investigate why this trade-off exists and whether hybrid or adaptive UCS formulations can simultaneously optimize convergence speed and asymptotic uncertainty sharpness in Bayesian optimization of prediction intervals for dam deformation.

• 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).

• Elastic Property Anisotropy in Inconel 718 Alloy Specimens Fabricated by Wire Arc Additive Manufacturing (2026) · doi

  While the paper demonstrates that Young's modulus reduction in the Z direction (perpendicular to deposition plane) reaches 10-11% in WAAM Inconel 718 and notes similar patterns in SLS-fabricated specimens, it does not systematically compare quantitative texture characteristics and mechanical property predictions between these two additive manufacturing technologies to establish technology-specific texture-property relationships.

• Modelling the effect of the water evaporation rate on total shrinkage of blended cement concrete (2026) · doi

  The coefficient α in the exponential decay function (Equation 5) was empirically correlated solely to 28-day compressive strength (α = −0.0015fcm + 0.118), despite the acknowledged influence of hydration rate and water-to-binder ratio on shrinkage behavior. Direct experimental quantification of how these material parameters independently affect the decay coefficient across different concrete compositions would improve model mechanistic basis.

• 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.