ENP Engineering Science Journal //enpesj.enp.edu.dz/index.php/enpesj <p>Ecole Nationale Polytechnique (ENP) is an academic and research institution where thousands of Engineers and PhDs have been educated during the last 6 decades. Its alumna and alumnus have had a positive impact on industry and science all over the world. ENP aims to disseminate high-quality academic work to contribute to technology and science advances for humanity.</p> <p>The ENP Engineering Science journal (ENPESJ) is a peer-reviewed open-access journal. It bi-annually publishes reviews and full original research papers covering all aspects of recent advances in engineering dealing with: </p> <ul> <li> Electrical and Computer Engineering</li> <li>Industrial Engineering</li> <li>Mechanical and Materials Engineering</li> <li>Civil and Hydraulic Engineering</li> <li>Chemical and Environmental Engineering</li> </ul> <p>The journal would focus also on technology with industry applications, it plans to publish special issues on up-to-date emerging technologies and new research directions. ENPESJ Promotes Open Science through truly free open access peer-reviewed journal articles.</p> en-US <p>Articles published under a Publisher Office user license are protected by copyright. Users may access, download, copy, translate, text and data mine the articles for non-commercial purposes provided that users:</p> <ul> <li>Cite the article using an appropriate bibliographic citation (i.e. author(s), journal, article title, volume, issue, page numbers, DOI and the link to the definitive published version)</li> <li>Maintain the integrity of the article</li> <li>Retain copyright notices and links to these terms and conditions so it is clear to other users what can and cannot be done with the article</li> <li>Ensure that, for any content in the article that is identified as belonging to a third party, any re-use complies with the copyright policies of that third party</li> <li>Any translations, for which a prior translation agreement with Publisher Office has not been established, must prominently display the statement: <em>"This is an unofficial translation of an article that appeared in a Publisher Office publication. Publisher Office has not endorsed this translation."</em></li> </ul> <p>This is a non commercial license where the use of published articles for commercial purposes is prohibited. Commercial purposes include: </p> <ul> <li>Copying or downloading articles, or linking to such postings, for further redistribution, sale or licensing, for a fee </li> <li>Copying, downloading or posting by a site or service that incorporates advertising with such content</li> <li>The inclusion or incorporation of article content in other works or services (other than normal quotations with an appropriate citation) that is then available for sale or licensing, for a fee</li> <li>Use of articles or article content (other than normal quotations with appropriate citation) by for-profit organizations for promotional purposes, whether for a fee or otherwise.</li> <li>Use for the purposes of monetary reward by means of sale, resale, license, loan, transfer or other form of commercial exploitation.</li> </ul> mourad.adnane@g.enp.edu.dz (Prof. Mourad ADNANE) ouiza.satour@g.enp.edu.dz (Ouiza SATOUR) Fri, 31 Dec 2021 00:00:00 +0000 OJS http://blogs.law.harvard.edu/tech/rss 60 Magnetic Field Calculation for Flat Permanent-Magnet Linear Machines Using a Hybrid Analytical Model //enpesj.enp.edu.dz/index.php/enpesj/article/view/36 <p>This paper proposes an improved two-dimensional (2-D) hybrid analytical method (HAM) in Cartesian coordinates, based on the exact subdomain (SD) technique and the finite-difference method (FDM). It is applied to flat permanent-magnet (PM) linear machines with dual-rotor. The magnetic field solution is obtained by coupling an exact SD model, calculated in all regions having relative permeability equal to unity, with FDM in ferromagnetic regions. The analytical model and FDM are connected in both axes (x,y) of the (non-)periodicity direction (i.e., in the interface between the tooth regions and all its adjacent regions as slots and/or air-gap). To provide accuracy solutions, the current density distribution in slot regions is modeled by using Maxwell’s equations. It is found that, whatever the iron core magnetic parameters, the developed HAM gives accurate results for no- and on-load conditions. Finite-element analysis (FEA) demonstrates excellent results of the developed technique.</p> LADGHEM CHIKOUCHE Brahim, Kamel Boughrara, Frédéric Dubas, Lazhar Roubache, Rachid Ibtiouen Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/36 Fri, 31 Dec 2021 00:00:00 +0000 Comparative Study between precooled Claude Liquefaction Cycle and an Active Magnetic Regeneration Cycle applied to Hydrogen Liquefaction //enpesj.enp.edu.dz/index.php/enpesj/article/view/12 <p><br />The present work aims at performing a comparative study between precooled Claude cycle and an Active Magnetic Regeneration Cycle (AMR cycle) applied to hydrogen liquefaction. It deals with a comparison between performances and energy consumption evaluated for the two systems at similar operating conditions. For Claude system, energy and material balances have been performed by using Aspen Hysys simulator. Thus, liquefaction power, energy consumption and coefficient of performance (COP) have been calculated. While, the AMR system considered is constituted of 6 stages operating in cascade. Each stage contains two regenerator beds, composed of a typical magnetic material, through which a carrier fluid is forced to follow alternatively between two heat reservoirs. Thermal analysis and evaluation of performances have been performed at once by a numerical model, developed on the basis of energy equations for fluid and solid within the regenerator bed, and Aspen Hysys simulator. Using the following magnetic materials (Gd, Dy, Tb and Ho), the COP found for the AMR system is 0.096. This value is higher than Claude cycle efficiency for which a COP of 0.094 was found. In terms of energy consumption, the value found for the AMR cycle is 0.053 kW which can be neglected compared to the Claude cycle consumption (14.5 kW).</p> Mustapha Belkadi, Arezki Smaili Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/12 Fri, 31 Dec 2021 00:00:00 +0000 Simplified Diagnosis Method for CHBMIs under Open-circuit Switch or Battery Failure //enpesj.enp.edu.dz/index.php/enpesj/article/view/23 <pre>This paper deals with the diagnosis of cascaded H-bridge multilevel inverters controlled by a sinusoidal level-shifted pulse-width modulation technique. For this purpose, the behaviour of 3, 5, 7 and 9-level inverters is studied for regular and faulty operation modes. Three types of recurring faults are considered, namely open-circuit of a switch, damaged and disconnected battery. Under a single fault, the output voltage signals are presented where the impact of each fault is discussed. In order to detect, identify and locate the three types of fault, a signal processing method is proposed, elaborating the output voltage of inverters with and without fault. The obtained results are convincing for the considered cases. The study shows no real correlation between the selected features from one to the other type of fault. Indeed, each fault type has its own trajectory with respect to the evolution of the output voltage characteristics. Thus, localizing the faulty component within the multilevel inverter can be made with no ambiguity. Such findings obviously solve a large part of problems associated with the presence of faults in multilevel inverters. They can help improving the reliability of the inverter in such way it continues working.</pre> Omar Kherif, Tahar Zebbadji, Youcef Gherbi, Mohamed Larbi Azzouze, Madjid Teguar Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/23 Fri, 31 Dec 2021 00:00:00 +0000 Polluted Barrier Effect on the Electric Field Distribution in Point-Plane Air Gaps under AC Applied Voltage: Based on Experimental Model //enpesj.enp.edu.dz/index.php/enpesj/article/view/21 <p>The aim of this paper is to study the effect of the surface condition of an insulating barrier on the electric field distribution in point-plane air gaps with the presence of a space charge, under AC voltage. The pollution was modelled as a uniform conductive layer on the barrier surface. Electric field analysis was carried out by changing the conductivity, permittivity, and thickness of the pollution layer. Using the Finite Element Method (FEM), the geometric model has been implemented in COMSOL Multiphysics software. This method is used to solve the partial differential equations that describe the field with the presence of space charge. The electric field increases when the conductivity and thickness of the polluted layer increases. Uniform pollution on the side of the high voltage point greatly reduces the insulation quality of the barrier. In addition, a limit level of pollution, from which its minimal electric strength is equivalent to that of a conductive barrier, has been determined. This model has been validated by comparing with the experimental results of a point-barrier-plane configuration with a distance between electrodes equal to 5cm. The distribution of the electric field predicted by the numerical model is in accordance with the experimental results. The latter indicate that this model has a great contribution in the physics of discharges in the air under various polluted environments.</p> Mohamed Abdelghani Benziada, Ahmed Boubakeur , Abdelouahab Mekhaldi Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/21 Fri, 31 Dec 2021 00:00:00 +0000 Analysis and mapping of mining subsidence and underground voids collapse risk using GIS and the weights-of-evidence model for the abandoned Ichmoul mine, Algeria //enpesj.enp.edu.dz/index.php/enpesj/article/view/46 <p>The present study concerns the assessment of mining subsidence and old underground works collapse hazard of the abandoned Ichmoul mine (Batna, Algeria) using the geographic information system (GIS) and the weight of evidence method (WofE). After the identification of collapse cases on the site and developing a spatial database for old underground works, topography and geology, the weight of evidence model was applied to calculate the weight of each relevant factor. Five main factors controlling or related to subsidence and underground voids collapse were determined from the probability analysis of existing cases; the underground voids depth, the distance between the underground voids, the landforms slope, the lithology and the distance between the fractures. Conditional independence tests were performed for the choice of factors. For the analysis of the subsidence and underground void collapse spatial hazard mapping, the contrast values, W+ and W- of the each factor evaluation were analyzed. The analysis results were validated using the curve ROC (AUC) with a past collapse case. For all the factors used, the area under the (ROC) curve showed 92 % accuracy. The results obtained can be used for the prevention of mining subsidence and underground voids collapse risks and the mine site rehabilitation.</p> Nassim Larachi, Abderrahim Bali, Abderrezak Ait Yahiatene , Malek Ould Hamou Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/46 Fri, 31 Dec 2021 00:00:00 +0000 Numerical investigation on mechanical properties of a nanobiocomposite based on date palm fiber and nanoclays with interphase problem //enpesj.enp.edu.dz/index.php/enpesj/article/view/29 <p>The use of biocomposites has been a major concern in recent decades with the emergence of composites as materials that can replace conventional ones. To improve the mechanical properties of these materials, special attention is devoted to nano-reinforcements. Among these nano-reinforcements, NanoClays (NC) are attracting the attention of many researchers. This nanoparticle, in addition to being biobased, has good mechanical properties and its nanometric dimension allows it to be an interesting reinforcement for the composite because of the NC/Matrix surface contact that it develops. In this study, a 4-phase material (Matrix, NC, Palm fiber and interphase) will be studied and the effect of several parameters (Aspect Ratio (AR), distance between NC and loading point, interface thickness and interfacial conditions) will be assessed and discussed. To do this, a 3D FEM model is developed and a mesh convergence study is pre-established.</p> Khaled MELIANI, Said RECHAK Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/29 Fri, 31 Dec 2021 00:00:00 +0000 Near Real-Time Low Frequency Load Disaggregation //enpesj.enp.edu.dz/index.php/enpesj/article/view/15 <p>Device-level power consumption information can lead to considerable energy savings. Smart meters are being adopted in several countries, but they are only capable of measuring the total power consumption. NonIntrusive Load Monitoring (NILM) aims to infer the power consumption of individual electrical loads by analyzing the aggregate power signal taken from a single-point measurement. Most existing NILM solutions are offline methods that do not allow the end-user to get real-time feedback on his energy consumption. In this paper, we present a near real-time NILM solution based on multi-label classification and multi-output regression. We use the multi-label classifier to predict the state of each load and use the multi-output regressor to estimate the disaggregated active power consumptions. We test our method using a publically available dataset of real power measurements. Performance results show that the proposed near real-time method can accurately estimate the energy consumption of the targeted loads with an average relative energy error of 1.55 %.</p> Selim Sahrane, Mourad Haddadi Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/15 Fri, 31 Dec 2021 00:00:00 +0000 The Investigation of Diethyl Hexyl Phthalate Migration from Poly(Vinyl Chloride) Serum Bags //enpesj.enp.edu.dz/index.php/enpesj/article/view/48 <p>Plasticizers are used to make Poly (Vinyl Chloride) (PVC) flexible so it can be used in different areas such as intravenous solution containers. Plasticizers can migrate from PVC over time because of contact with these solutions; this phenomenon creates gaps in the polymer structure and causes the migration of other additives. This paper discusses the specific migration of di-2-ethyl hexyl phthalate (DEHP) from plasticized poly (vinyl chloride) (PVC) into 5% glucose solution, although studying the possibility of migration of other components. For this purpose, the bags were stored in real conditions by respecting temperatures (20 ± 2°C) and time of conservation (18 months). Samples were taken off every 3 months to be analyzed. The Fourier transform infrared spectroscopy was used to investigate the migration phenomena, the atomic absorption spectrometry was used to follow the migration's evolution of metals from plastic bags and the gas chromatography coupled with mass spectrometry was used for the determination of DEHP migration. The results obtained by the three techniques showed the migration of the serum bags additives such as DEHP in the glucose solution. This migration depends on time of contact.</p> Dalila IKERMOUD, Naima Belhaneche-Bensemra, Hicham Benaissa Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/48 Fri, 31 Dec 2021 00:00:00 +0000 Modal identification and dynamic analysis of a 1000 years old historic minaret of Kalaa Beni-Hammad //enpesj.enp.edu.dz/index.php/enpesj/article/view/56 <p>From structural and material point of view each historic monument is a textbook case, as it differs in shape, age, material characteristics and level of preservation. New means and approaches are used for geometric and shape survey, material and modal characterization, which helps restitute detailed information regarding the structural elements of the edifices. This paper investigates a 1000 years old historic minaret having a square base of 6.50 m of side and 24.70 m height. An ambient vibration survey has been carried out and the results were used to update a Finite Element (FE) model of the minaret in two stages. First, the elastic modulus of the rubble stone masonry has been determined by matching the experimental and numerical fundamental frequency. In a second phase, a frequency response function (FRF) correlation is carried out iteratively by adjusting the damping ratios to minimize the FRF error. The elastic modulus of the rubble stone masonry is found to be in the lowest range of values given in the literature, which confirms a deteriorated quality of the material. A seismic performance of the structure has been carried out using the updated FE model subjected to a set of acceleration time histories having the mean spectrum matching a compatible site spectrum. The stress concentration zones have been determined and a steel tie system to retrofit the structure is proposed. Beside the proposed investigation framework, the characterization results are valuable facts that can be added to the available database of historic monuments.</p> Nouredine Bourahla, Zakaria Assameur, Mohamed Abed, Ahmed Mébarki Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/56 Fri, 31 Dec 2021 00:00:00 +0000 A Differential Pressure Technique for Void Fraction Measurement in Gas-Liquid Flow //enpesj.enp.edu.dz/index.php/enpesj/article/view/61 <p>Two-phase Gas-liquid flows have many industrial uses, such as hydrocarbon transportation and energy production. The knowledge and an accurate determination of the gas phase's proportion rate in the two-phase mixture known as the gas void fraction is necessary for optimal and secure sizing of the installations where this kind of flow takes place. This paper focuses on the possibility of using a cost-effective differential pressure transmitter to measure the void fraction parameter. It is obtained using a mathematical model derived from the energy balance equation and the measured pressure drop from the vertical upward gas-liquid flow. Results on flow void fraction obtained through the use of the conductance probe method, are used to validate those derived from the pressure drop that is evaluated by employing the differential pressure transmitter. The measurement accuracy of the void fraction measured using the pressure drop technique, is found to be principally affected by the flow pattern. Moreover, the slip ratio between the phases was the primary factor influencing the void fraction measurement by the differential pressure technique.</p> Ammar ZEGHLOUL, Abdelwahid AZZI, Nabil GHENDOUR, Abdallah Sofiane BERROUK Copyright (c) 2021 ENP Engineering Science Journal https://creativecommons.org/licenses/by-nc-sa/4.0 //enpesj.enp.edu.dz/index.php/enpesj/article/view/61 Fri, 31 Dec 2021 00:00:00 +0000