Data gaps in Engineering

Representative open questions

Showing 30 of 50 — one per source paper, highest-quality first.

• Challenges and Frontiers in the Circularity of Polymer Additive Manufacturing: A Systematic Review of Recycling Pathways and Material Degradation (2026) · doi

  The mechanical degradation of recycled polylactic acid (PLA) and polyhydroxybutyrate (PHB) filaments after multiple thermomechanical processing cycles has not been systematically quantified across different reprocessing iterations, limiting understanding of the maximum number of reprocessing cycles these materials can tolerate before performance becomes unsuitable for additive manufacturing.

• Friction Stir Welding of Dissimilar Materials: A Comprehensive Study on Joining Stainless Steel to Ni, Ti, and NiTi Alloys (2026) · doi

  The paper identifies that even a 0.1% shift in the Ni/Ti ratio can alter transformation temperatures and render NiTi shape memory effect useless, but does not provide quantitative mapping of how specific elemental losses during dissimilar FSW of SS-NiTi correlate to measurable changes in austenite/martensite transformation temperature ranges.

• 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.

• Electrically switchable continuous phase liquid crystal Fresnel zone plate (2026) · doi

  The paper documents that the HAN configuration introduces competing boundary conditions with non-uniform hybrid director profiles that slow the electro-optic response, particularly in the rise time. However, systematic experimental investigation comparing rise and fall times between devices fabricated at 0 Vpp (to avoid HAN) versus the current 100 Vpp fabrication approach has not been conducted to quantify the actual performance improvement achieved.

• 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.

• Mechanistic modeling of primary drying of frozen particulates (2026) · doi

  The model predictions for effective thermal conductivity (keff) and mass transfer efficiency show strong correlations with tortuosity and porosity metrics, but the relative importance of these structural parameters has not been systematically decoupled across a broader range of particle bed geometries and packing densities beyond the three particle types tested.

• Sensor Data Fusion in Healthcare Monitoring System with Appropriate Rule-based Model for Error Reduction (2026) · doi

  The study evaluated the ORSF-HMM-SDL fusion model on only 10 patients across three sensor types (heart rate, blood pressure, temperature); validation on larger and more diverse patient populations with additional sensors (glucose, oxygen) integrated into the fusion framework is needed to establish generalizability.

• 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.

• Introduction to Surface Chemistry Essentials (2013) · doi

  The paper describes oil-water emulsion instability (coalescence within minutes for 1 mm diameter drops) but provides no systematic data on emulsifier molecular structure requirements, interfacial tension reduction thresholds, or coalescence kinetics across different oil types and water compositions. Controlled experiments varying surfactant architecture and oil-water interfacial properties are needed to establish design criteria for stable emulsions in pharmaceutical and cosmetic applications.

• 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.

• Electron-donor/-acceptor ratio-guided molecular engineering for buried interface optimization in n-i-p perovskite solar cells (2026) · doi

  The mechanism by which EDG-rich molecules reduce perovskite grain boundary density is attributed to 'retarded crystallization' and 'enhanced film uniformity,' but quantitative crystallization kinetics data (nucleation rates, grain growth dynamics) and direct microscopic comparison of grain boundary evolution between modified and unmodified samples during film formation are absent.

• 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.

• Coal seam porosity and water resources estimation based on big data analysis and deep learning models: A case study in the Surat Basin, Australia (2026) · doi

  Image logs from 21 wells captured 919 fractures total, but the authors acknowledge that 'smaller scale cleats are prominent but not captured' by image log interpretation in coal seams. The study does not investigate how undetected cleat networks at sub-image-log resolution affect the discrete fracture network (DFN) model predictions of coal seam porosity and permeability in the Surat Basin.

• IoT-Driven Transformer Health Monitoring and Fault Detection: Advancing Reliability in Emerging Power Systems (2026) · doi

  The system's performance under network connectivity interruptions is described qualitatively (Firebase real-time database with local caching for uninterrupted operation), but quantitative data on data loss rates, synchronization delays, and fault detection accuracy degradation during prolonged network outages in areas with unstable infrastructure is absent. Empirical validation of system reliability metrics under intermittent connectivity conditions needs measurement.

• False Positive Reduction in Emergency Vehicle Detection Using a Multimodal Edge-Based System (2026) · doi

  The acoustic module relies on Mel-Filterbank Energy features extracted by ESP32-S3 hardware, but there is no evaluation of how siren acoustic signatures vary across different emergency vehicle types (ambulances, fire trucks, police vehicles) or how geographic regional siren standards affect detection performance in international deployments.

• 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.

• Treatment of petroleum refinery wastewater by photo-anodic oxidation process with Gr /Bi-Ni-Sb-SnO2 rotating photo-anode: Performance and kinetic study (2026) · doi

  Ceramic electrodes based on Sb-doped SnO2 for removal of emerging compounds in wastewater need comparative studies across different pollutant types and concentrations.

• Portable electrochemical immunosensor for point-of-care testing of ovarian cancer biomarker HE4 in commercial human blood serum samples (2026) · doi

  No label-free electrochemical HE4 immunosensors have previously measured HE4 levels directly at pM concentrations, representing a gap in the existing literature.

• Cyber-Resilient IoT-Driven SCADA Integration for Secure and Intelligent Fuel Station Monitoring and Predictive Analysis (2026) · doi

  The dataset used for model evaluation was limited to approximately 14 days of operation across 4 tanks with 10 sensors (480k records), which may not capture seasonal variations or long-term degradation patterns.

• Biochar-regulated transport of weakly hydrophobic antibiotics between macropore and matrix domains in structured soil (2026) · doi

  The magnitude of biochar's regulatory effect is specific to the 1% (w/w) crop-residue biochar employed; variations in feedstock, pyrolysis temperature, and dosage will inevitably alter physicochemical properties and modulate the pump's efficiency, requiring further investigation.

• Operation Sindoor : A Portrayal of Indian Media Representation Against Terrorism (2026) · doi

  No empirical data or quantitative analysis is provided to measure the extent of fake news, AI-generated content, or misinformation spread during Operation Sindoor.

• Parametric Evaluation of Mechanical and Surface Characteristics in FDM-Based 3D Printing (2026) · doi

  The study only examined three materials (PLA, ABS, and nylon) and three process parameters (printing speed, temperature, and layer height); other materials and parameters relevant to FDM printing were not explored.

• Artificial neural network-based approach for optimized photovoltaic grid injection using a three-phase multilevel inverter (2026) · doi

  Testing was conducted under limited irradiance levels (0.1–1 kW/m²) and a single sudden change scenario (1000 W/m² to 300 W/m²); broader environmental conditions and more diverse grid disturbance scenarios need evaluation.

• BIM Technology in Intelligent Driving Simulation: Potentials and Challenges to Address Virtual Environment Deficiencies (2026) · doi

  There is no standardised data interface for importing BIM models into simulation platforms. Different simulators use distinct specifications (openDRIVE, Lanelet, SUMO XML) and there is currently no general method for converting Building/Road BIM models into recognisable elements for simulations.