Data gaps in Engineering

Representative open questions

Showing 30 of 54 — 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 shift from N-A-S-H to C-N-A-S-H gel chemistry in MK-BP composites has been identified via FTIR spectroscopy, but the quantitative relationship between Ca²⁺ incorporation rate, BP content (10–25%), and the resulting mechanical performance improvement (strength, shrinkage) has not been established through controlled experimental design.

• Overcoming the Achilles Heel of flow chemistry: strategies for solid handling in heterogeneous continuous-flow reactors (2026) · doi

  Particle residence time distribution in helical tube devices has been studied (reference 50), but suspension flow behavior characterization specifically for metal nanoparticle catalysts in continuous-flow slurry reactors with varying particle loadings and sizes requires systematic investigation to optimize solid handling performance.

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

  The significant strength differential between overlay concrete (41.86 MPa) and substrate concrete (19.93 MPa) is noted to affect interfacial stress distribution and failure mode transitions, but no parametric study investigates how varying substrate-to-overlay strength ratios influence bond performance across different loading conditions.

• Optimization of drying and packaging strategies for preserving phytochemicals, nutrients, and bioactivity in Bauhinia purpurea petals (2026) · doi

  The study evaluated phytochemical retention across only three storage months (S1, S2, S3) for Bauhinia purpurea petals; extended storage stability beyond three months under the tested drying (solar, cabinet 40°C, cabinet 50°C, freeze-drying 40°C, freeze-drying 50°C) and packaging conditions (plastic bag, plastic bottle, aluminium foil bag, glass bottle) remains uncharacterized.

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

  Machine learning applications for defect detection in low carbon steel WAAM products employ cost-sensitive convolutional neural networks with remanence/magnetooptical imaging, but the validation dataset encompasses only limited defect types; expansion to diverse surface and subsurface defect morphologies is required.

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

  The Si@MOF electrode showed controlled expansion during cycling with PPG electrolyte, but the maximum tolerable volume expansion percentage before interfacial failure occurs and the relationship between MOF pore size/carbon matrix thickness and expansion buffering capacity remain unquantified for solid-state battery design optimization.

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

  Predictive performance of the uncertainty-aware Bayesian optimization framework is heavily dependent on instrumentation data availability and quality, yet the paper does not specify minimum sensor density, sampling frequency, or noise tolerance thresholds required for reliable uncertainty calibration in embankment dams. Systematic sensitivity analysis is needed to define quantitative data requirements for deploying this framework across sites with varying monitoring infrastructure.

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

  The passive vibration isolator design was optimized and tested at discrete temperatures (15°C, 25°C, 35°C) relevant to missile flight conditions; however, the dynamic response at intermediate temperatures and the rate of thermal transients during altitude changes have not been experimentally characterized.

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

  Stall cell instability produces unsteady loading on wind turbine airfoils with highly variable force coefficients at single angles of attack. Current practice of reporting single mean values for force coefficients under these conditions is inadequate; systematic characterization of probability density functions and higher-order statistics across different thickness ratios and Reynolds numbers is needed for wind turbine aerodynamic data.

• Design And Implementation of Low Power and Low Area RISC Core Using Vedic Mathematics (2026) · doi

  The paper claims reduced power consumption and area through hierarchical decomposition of the Vedic multiplier but provides no silicon area measurements, power dissipation values in watts or milliwatts, or energy efficiency comparisons (measured in pJ/operation) against baseline and state-of-the-art RISC processor designs.

• Smart Gloves for Sign Language to Text Conversion Translation Using Arduino Mega With 8 Flex Sensors (2026) · doi

  Power consumption is listed as 'moderate' without quantitative specification (mAh, hours of continuous operation, battery requirements). A detailed power budget analysis comparing flex sensor polling frequency, Arduino Mega processing cycles, DF Player audio amplification, and LCD display draw is needed to enable portable battery-powered deployment.

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

  The power supply unit incorporates 12V/5V regulators for mixed-voltage components (sensors, microcontroller, motors), but the paper lacks analysis of power consumption load profiles, voltage stability under peak demand (all gates/sensors active), or backup power requirements for continuous operation.

• Telekit: a bilateral, teleoperated platform for hands-on learning (2026) · doi

  Discrepancies exist between perceived stiffness (0.42±0.1 N/°) and actual spring stiffness (0.67 N/°), attributed to system compliance, sensor noise, and time delays. The relative contributions of these individual factors to the overall stiffness perception error in bilateral teleoperation have not been systematically isolated or quantified.

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

  No open benchmarking repositories exist for cross-domain validation of early failure detection models across transformer DGA, wind turbine vibration spectra, and SCADA photovoltaic logs; security restrictions on nuclear and grid system data prevent standardized comparative assessment metrics and reproducibility of modeling paradigms.

• Ventilator-integrated humidified cold atmospheric plasma enables safe eradication of lung cancer cells and supports respiratory therapeutic applications (2026) · doi

  The correlation analysis computed Pearson correlation coefficients among H₂O₂, NO₂⁻, and NO₃⁻ concentrations across experimental conditions, but did not investigate whether these reactive species correlations vary as functions of specific applied voltage ranges, treatment duration intervals, or humidity levels that may reveal mechanistic dependencies.

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

  Large-scale industrial datasets for AM quality assurance in wind turbine blade production do not exist. Most reported performance metrics derive from laboratory-scale experiments and synthetic datasets rather than real utility-scale manufacturing environments, preventing validation of AI models at production scale.

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

  The algorithm was tested on independent experimental datasets demonstrating outer race defect development; validation against bearing failure modes involving simultaneous multiple defect types (e.g., outer race + lubrication degradation, or outer race + cage wear) is not reported, limiting confidence in real-world multi-failure scenarios.

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

  Regenerative braking behavior is observed qualitatively during deceleration phases but lacks quantitative analysis of energy recovery efficiency, braking force distribution, and integration with the AHA optimal control strategy across the three drive cycles.

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

  The elastic property anisotropy measurements (Young's modulus, shear modulus, Poisson's ratio) are reported for three orthogonal directions (X, Y, Z), but the paper lacks investigation of elastic properties at intermediate angles or analysis of the complete 6×6 elastic stiffness matrix to fully characterize anisotropic behavior in WAAM specimens.

• Nonlinear predictive control of the catalytic reforming process based on a hybrid model [in Ukrainian] (2026) · doi

  Simulation results (Figure 4) compress 45 days of real plant operation into 48 simulation hours; validation of the proposed hybrid model adaptation mechanism against actual industrial catalytic reforming data over extended operating periods (weeks to months) between regenerations is needed.

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

  The model assumes constant 50% increase in total shrinkage before peak time based on results fluctuating between 40-60% from 38°C chamber testing. The relationship between water evaporation rate and the magnitude of pre-peak shrinkage increase for concretes exposed to different field temperature and humidity conditions needs experimental characterization to validate the adopted linear approximation.

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

  The experimental validation dataset covers only six coolant compositions (base EG plus 1%, 2%, 3%, 4%, and 5% Al₂O₃ nanoparticle concentrations) with incomplete experimental measurements reported for some conditions (Table 9 shows missing data points). The machine learning model's generalization capability beyond this narrow nanoparticle concentration range and for alternative nanoparticle materials beyond Al₂O₃ remains unvalidated.

• Recent advances in polyoxothiometalate chemistry (2022) · doi

  The hydrogen evolution reaction (HER) electrocatalytic activity of polyoxothiometalate complexes has been evaluated on only a limited set of POTM structures (Figure 12). Comprehensive screening of how POTM cluster size, metal composition (Mo versus W), sulfur coordination modes, and organic ligand frameworks (BTC, PyD, Nap, DTO) affect overpotential and catalytic efficiency remains incomplete.

• Prediction of unconfined compressive strength of fly ash and waste paper sludge stabilized clayey soil using explainable machine learning (2026) · doi

  The indirect and interaction-driven role of WPS in stabilization is identified through SHAP values concentrated around ±35, indicating minimal direct contribution, but the optimal WPS dosage and its synergistic effects with fly ash at varying curing periods have not been systematically characterized through sensitivity analysis.

• Translational dynamics of bridled kites: a reduced-order model in the course reference frame (2026) · doi

  Aerodynamic polar curves for soft kites are frequently underpredicted by numerical methods, requiring empirical corrections based on flight data. A systematic characterization of drag coefficient discrepancies (CL, CD, CDα) across different soft kite designs and wing loadings is needed to improve quasi-steady model accuracy without ad-hoc calibration.

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

  The interaction between Winkler coefficient variations and applied voltage on relative frequency change is characterized theoretically, but the paper lacks experimental data on how this coupling behaves across different foundation stiffness values (Winkler coefficient 1-4) in real sports engineering installations with dynamic load conditions.

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

  Separator membrane selection significantly impacts MFC scaling, yet comparative performance data for bipolar membranes, glass fibers, ultrafiltration membranes, and porous textile materials in ion diffusion enhancement are lacking; systematic evaluation of these separator materials under standardized operating conditions is needed.

• Small-scale water energy harvesting for sustainably-powered distributed electronics (2026) · doi

  Ionized hydrogel-based moisture-enabled generators (MEG) achieved underwater wireless transmission at ~1.0 V output; however, the sustained power delivery duration, voltage stability under varying water salinity/temperature conditions, and communication range limitations for practical underwater monitoring systems remain unspecified.

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

  The reference to discrete ply models in compact tension testing (Rutar et al., 2025) indicates that R-curve prediction for CFRP under hygrothermal aging using discrete ply simulation remains unvalidated in the context of varying environmental conditions affecting translaminar fracture behavior.

• Smart Electrochemical Sensors and IoT for Monitoring Heavy Metals in Nigerian Water: Review of Advances and Deployment Challenges (2026) · doi

  While low-cost IoT water quality sensor systems are reviewed, cost-benefit analysis comparing the deployment of electrochemical heavy metal sensors versus inductively coupled plasma mass spectrometry or neutron activation analysis in resource-limited Nigerian settings is not provided. Economic feasibility and accuracy trade-offs specific to rural Nigerian water monitoring infrastructure need quantification.