Publications

Predictive Models with Applicable Graphical User Interface (GUI) for the Compressive Performance of Quaternary Blended Plastic-Derived Sustainable Mortar

Machine learning (ML) models in material science and construction engineering have significantly improved predictive accuracy and decision making. However, the practical implementation of these models often requires technical expertise, limiting their accessibility for engineers and practitioners. A user-friendly graphical user interface (GUI) can be an essential tool to bridge this gap. In this study, a sustainable approach to improve the compressive strength (C.S) of plastic-based mortar mixes (PMMs) by replacing cement with industrial waste materials was investigated using ML models such as support vector machine, AdaBoost regressor, and extreme gradient boosting. The significance of key mix parameters was further analyzed using SHapley Additive exPlanations (SHAPs) to interpret the influence of input variables on model predictions. To enhance the usability and real-world application of these ML models, a GUI was developed to provide an accessible platform for predicting the C.S of PMMs based on input material proportions. The ML models demonstrated strong correlations with experimental results, and the insights from SHAP analysis further support data-driven mix design strategies. The developed GUI serves as a practical and scalable decision support system, encouraging the adoption of ML-based approaches in sustainable construction engineering.

Semi-analytical calculation of all magnetic values of a superconducting toric storage

For particular applications, the design of systems composed of several superconducting coils needs good accuracy in calculations. Using analytical methods involving elliptic integrals, themselves calculated using the AGM method, all electromagnetic values can be evaluated with a good precision. An application to a superconducting toroidal core illustrates this study.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Study and simulation of space vector PWM control of double-star induction motors

This paper deals with a comparison between different structures of double-star induction motors (DSIMs), controlled by space vector PWM. The modelling of the DSIM is made using an arbitrary shift angle between the two three-phase windings. A new transformation matrix is proposed to develop a suitable dynamic model and to elaborate the space vector PWM control strategy for different values of this shift angle. Simulation results are presented and compared. The effects of the shift angle on the dynamic performances, and on the complexity of calculating the PWM control strategy, are pointed out.

Sustainable ultra-high-performance basalt fiber-reinforced geopolymer concrete incorporating carbon nanotubes and treated recycled aggregates

Comparative Study of Three Minimization Methods Applied to the Induction Machine Parameters Identification Using Transient Stator Current

To identify the parameters of asynchronous machines, many methods are used. Many of them need a derivative during the optimization process. Unfortunately, a derivative function amplifies any noise due to numerical calculation or to measurement. As a consequence the search of the vector of parameters becomes difficult. Three minimization methods without derivatives are presented and applied to the identification of the parameters of induction motors. They allow finding both electrical and mechanical parameters from the analysis of the starting stator current and the corresponding voltage. Firstly, each method is described. Secondly, for a given machine with known parameters, numerical simulations allow to test the methods in terms of computer consuming time, of convergence and uniqueness of solution. The last part is devoted to the applications of the methods in order to identify the parameters of two asynchronous machines.

An induction motor model including the first space harmonics for broken rotor bar diagnosis

Abstract This work presents a model of a three‐phase induction machine which includes the first space harmonics of the magnetomotive force. Special attention has been paid to the way of improving detection of broken rotor bars. This detection is based on the spectral analysis of the stator current. We show that it is essential to extend the analysis to the amplitudes of the side bands due to the space harmonics. This thorough method makes it possible to detect with a higher degree of accuracy the type and the importance of a defect in the rotor cage. Copyright © 2005 John Wiley &amp; Sons, Ltd.

Real-time implementation of the sliding DFT applied to on-line's broken bars diagnostic

Electric motors have a very important role for safe and efficient running in many industrial or power plant. Early detection of abnormalities in the motors contributes to avoid expensive failures. It has been shown that rotor faults can be detected thanks to the spectral analysis of the stator current using FFT/DFT algorithms. They are usually performed and analysed offline after data acquisition. The proposed method allows to obtain the DFT immediately after the arrival of each new sample. This technique is suitable for the online running spectral analysis of the stator current in order to detect the components due to rotor broken bars while the machine is operating. Experimental results show the efficiency of the proposed method for an online diagnostic.

Modified Vector Control for Saturated Induction Machine by considering a series iron losses equivalent circuit

Vector controlled induction machine drives are increasingly used in industrial drive systems, but the drive performance often degrades with the machine parameter variations. In this paper, a modified vector control system is proposed to achieve decoupling when saturation and iron losses are taking into account. The simulated and experimental results of the modified controller are presented to verify the effectiveness of the proposed approach.

Centrifuge modelling of capillary rise

Scaling Laws for Centrifuge Modeling of Capillary Rise in Sandy Soils

The application of geotechnical centrifuge modeling to environmental problems seems promising. In this paper, one aspect of similitude laws concerning the flow of water through soils is investigated. Within the Network of European Centrifuges for Environmental Geotechnic Research, several tests have been carried out to study similitude laws describing the capillary ascension in porous media at different levels of acceleration. The aim of this paper is to present the results obtained at Ruhr-Universität Bochum. A fine sand is used in the experiment. For the visualization of capillary height in the soil sample, image processing is used. Different boundary conditions (constant or variable water level) have been investigated and discussed. All these experiments confirm that capillary rise appears scaled by the factor N and time seems to be scaled with N2. Thus, these results support the possibility of extending the use of accelerated small-scale models to the capillary phenomenon in centrifuge and open the way to more complex investigations of flow and pollutant transport in unsaturated soils.

Investigating Energy Reduction and Flow Dynamics Around Bridge Abutments with Eco-Friendly Materials

<title>Abstract</title> Bridge abutment is the most critical civil engineering infrastructure directly exposed to floodwater. Previous research focused on the bridge abutment scouring under diverse flow conditions with different types of countermeasures. To date, no study has been conducted to observe energy reduction and flow dynamics around bridge abutment. Therefore, the current research investigates energy reduction and flow dynamics around bridge abutments with eco-friendly materials (brick waste (BW) and marble waste (MW)) under subcritical flow conditions. Experiments were performed in a controlled laboratory setting to investigate different parameters such as water surface profile, energy reduction, reduction of fluid force index (RFI%), moment index (RMI%), and delay in floodwater arrival time. These parameters were investigated under different conditions including without waste (WW) and with eco-friendly materials. The result demonstrates that energy reduction increases by increasing the Froude number (Fr) from 0.13 to 0.22. Energy reduction increases up to 5.95%, 6.5%, and 6.27% in the case of WW, MW, and BW respectively. The use of MW resulted in maximum energy reduction where the average energy reduction reached 4.38%. The highest RFI% of 8.86% and RMI% of 12.44% were recorded with the use of MW during the experiments. The findings also show that a significant reduction in floodwater arrival occurred in the case of MW up to 68% compared to without abutment case in the channel. These findings provide valuable insights into flow characteristics and energy dissipation around bridge abutments, contributing to sustainable and resilient hydraulic infrastructure design.

Eddy Current Computation in Translational Motion Conductive Plate of an Induction Heater With Consideration of Finite Length Extremity Effects

An electromagnetic model is proposed to compute translational motion eddy currents in a conductive plate. The eddy currents are due to the movement of the plate in a dc magnetic field created by a permanent magnet (PM) inductor. First, the magnetic field, due to the PMs, is computed in three dimensions, where the iron yokes' influence is considered because of the method of images. Then, the motional eddy currents are computed, such that the edge effects are correctly considered through an iterative procedure that uses magnetic images. The computations are very fast, and the obtained results are close to those issued from the three-dimensional finite-element method and the experiments.

Magnetic field concentration: comparison between several shapes of superconducting shields

This paper deals with a system of flux density concentration using superconducting shields. The development of single grain high, temperature superconductors allows the conception of large sized magnetic shields. These shields force the flux density to be concentrated by modifying its spatial distribution. The authors' system consists of two low field solenoids, which have the same arrangement as Helmoltz coils. Between these two coils, two superconducting plates are arranged on both sides of the axis. For this study, the superconductor is considered as perfect. They propose to discuss the efficiency of several concentrating devices. To make their study, they performed a 3D-field calculation tool using a Monte-Carlo method. The main advantage of this method is a very simple algorithm to compute, even if the geometry is complicated. The authors have shown that if the distance between the two plates is small enough in respect to the coils diameter, the flux density is much higher than the one inside the coils. They also show the influence of the shape of the shields in the guidance of the flux lines. They have validated their simulations with an experiment.

Analytical calculations of flux induction and forces of thick coils with finite length

The analytical modeling of toric coils is considered. The mathematical relations involve elliptic integrals which are rapidly and easily calculated using the arithmetic geometric mean (AGM) method. Two applications are studied, numerical results are analyzed and compared, when possible, with those obtained directly. The analytical method presented provides all the characteristics (such as inductances, flux densities, forces, etc.) of toric coils with any section. Thanks to the AGM method, which is used for intermediate calculations, the final results are obtained rapidly with a very good precision.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Dimensionless and analytical studies of the thermal stability of a high temperature superconducting tube

A Simple and Efficient Tool for Design Analysis of Synchronous Reluctance Motor

This paper presents an efficient tool for design analysis of a Synchronous Reluctance Motor (SynRM).The Winding Function Analysis (WFA) is used instead of the Finite Element Analysis (FEA).With WFA approach, parameters sensitivity analysis and the impact on the machine design can be evaluated very rapidly (under linear condition).The effect of rotor skewing, stator winding chording, pole arc and interpolar air-gap length on average torque and torque ripple is investigated.The results obtained by WFA are compared with those obtained by two-dimensional FEA.It is shown that the two methods give approximately the same results but require different computation time.

Influence of Jc(B) on the full penetration current of superconducting tube

Advanced Prediction Models for Scouring Around Bridge Abutments: A Comparative Study of Empirical and AI Techniques

Scouring is a major concern affecting the overall stability and safety of a bridge. The current research investigated the effectiveness of the various artificial intelligence (AI) techniques, such as artificial neural networks (ANNs), the adaptive neuro-fuzzy inference system (ANFIS), and random forest (RF), for scouring depth prediction around a bridge abutment. This study attempted to make a comparative analysis between these AI models and empirical equations developed by various researchers. The current research paper utilized a dataset of water depth (Y), flow velocity (V), discharge (Q), and sediment particle diameter (d50) from a controlled laboratory setting. An efficient optimization tool (MATLAB Optimization Tool (version R2023a)) was used to develop a scour estimation formula around bridge abutments. The findings of the current investigation demonstrated the superior performance of the AI models, especially the ANFIS model, over empirical equations by precisely capturing the non-linear and complex interactions between these parameters. Moreover, the result of the sensitivity analysis demonstrated flow velocity and discharge to be the most influencing parameters affecting the scouring depth around a bridge abutment. The results of the current research highlight the precise and accurate prediction of the scouring depth around a bridge abutment using AI models. However, the empirical equation (Equation 2) demonstrated better performance with a higher R-value of 0.90 and a lower MSE value of 0.0012 compared to other empirical equations. The findings revealed that ANFIS, when combined with neural networks and fuzzy logic systems, produced highly accurate and precise results compared to the ANN models.

Signal analysis and identification for induction motor sensorless control