2024
Bendrihem K-A, Zeraib A, Atoki A-V, Mihoubi M-A, Kadi K, Bensuici C, Hachemi M, Ayeb N-E, Messaoudi M.
Phytochemical screening, antioxidant properties, and photo-protective activities of Salvia balansae de Noé ex Coss. Open Chemistry [Internet]. 2024;22 :1-18.
Publisher's VersionAbstractThe present study evaluated the potential of Salvia balansae from the Aures Mountains as a source of natural bioactive compounds. Leaves, flowers, and stems were extracted separately using methanol, ethanol, and acetone. Phenolic compounds were quantified colorimetrically and identified using liquid chromatography coupled with mass spectrometry (LC-MS). Antioxidant capacity was assessed using six different in vitro assays, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 1,1-diphenyl-1-picrylhydrazyl, cupric reducing antioxidant capacity, ferric reducing antioxidant power, ferrous ion chelating, and phenanthroline assay, while the photo-protective capacity was evaluated using the sun protective factor. The methanolic flower extracts revealed the highest O-diphenol and phenolic levels (287.9 ± 0.50 and 147.87 ± 0.21 µg GAE/mg, respectively), whereas the acetonic and ethanolic leaf extracts contained the highest flavonoid (72.17 ± 0.12 μg QE/mg) and flavonol (35.28 ± 0.05 μg QE/mg) levels, respectively. LC-MS was used to identify 18 phenolics, including quinic acid (5.051–69.69 ppm), luteolin-7-o-glucoside (7.802–44.917 ppm), apigenin-7-o-glucoside (3.751–68.507 ppm), and cirsiliol (2.081–15.608 ppm), distinguishing this Aures taxon. Principal component analysis and unweighted pair-group method with arithmetic mean revealed variability in phytochemicals, antioxidant properties, and photo-protective activity influenced by biological activities and the compound content. Overall, S. balansae demonstrated promising photo-protective capacity, the presence of key bioactive compounds, and wide-ranging antioxidant potential, presenting this endemic plant as a valuable source of natural antioxidants and photo-protective agents with pharmaceutical and cosmetic applications.
Benzina I, Bekdouche F, SI-BACHIR A.
Post-fire dynamics of recolonization by Cistus plants in the Aleppo pine and Cork oak forests in Bejaia region, central north Algeria. Environmental & Socio-economic Studies [Internet]. 2024;12 (2) :40-47.
Publisher's VersionAbstractIn August 2021, very intense fires swept through various forested areas in northern Algeria, particularly in Kabylia. The population dynamics of Cistus salviifolius and Cistus monspeliensis were studied along a post-fire successional gradient during the first nine months (September 2021 – May 2022), in two forest communities: the Cork oak (Quercus suber) and the Aleppo pine (Pinus halepensis) forests in the coastal zone of Bejaia province. The Cistus spp. germinations were counted monthly in each forest on 10 plots of 1 m2, evenly distributed along 2 transects of 45 m each. The results showed that the majority of germinations occur in December with 207.5 ± 24.2 seedlings in the Cork oak forest and 171.3 ± 18.0 seedlings in the Aleppo pine forest. Student’s t-test does not reveal significant differences for December between the two communities. During the first months following the fire (September and October 2021), germinations were almost absent. The monthly rainfall in September 2021 was estimated at 16.25 mm, an insufficient amount for effective germination. Late germination results in an extension of its period, showed a high rate in January 2022 with 42.2 ± 2.1 and 11.5 ± 0.8 seedlings, respectively, in the Cork oak forest and the pine forest. Beyond January, germination was practically nonexistent in both communities. Therefore, the majority of the seed germination was concentrated in November, December, and January with a unimodal germination pattern.
Mansouri L-M, Kheloufi A.
Salinity effects on germination of Portulaca oleracea L.: A multipurpose halophyte from arid rangelands. Journal of Applied Research on Medicinal and Aromatic Plants [Internet]. 2024;41.
Publisher's VersionAbstractSalt resistance studies have, unfortunately, mainly been focused on conventional crops, with very few studies being conducted on the potential of available halophytes as new crops in the future. Portulaca oleracea L. has been listed as one of the most used medicinal plants by the World Health Organization as an edible halophyte. It is a fast-growing herbaceous annual with high nutritional relevance. The present work was designed to determine the effect of six soluble salts (NaCl, Na2SO4, KCl, CaCl2, CaCO3, and MgCl2) on germination of P. oleracea seeds. The effect of salinity was tested on final germination percentage (FGP%), and germination tolerance index (GTI%) using five concentrations (0, 200, 300, 400, and 600 mM) of each salt. In addition, laboratory experiments were conducted to assess the effects of salinity on germination recovery from high saline conditions (600 mM). Salinity level and salt composition significantly influenced germination attributes. P. oleracea seeds were non-dormant, exhibited approximately 100% germination in distilled water. Both FGP and GTI gradually decreased with increasing salinity. This study showed that seeds of P. oleracea can germinate under 300 mM in all tested salts. The salts causing germination inhibition exhibited specificity, with an increasing trend observed in the following sequence: MgCl2 > Na2SO4 > NaCl > KCl > CaCl2 > CaCO3. Transferring ungerminated seeds from 600 mM to distilled water recovered their germination ability. Based on these results, we can conclude that P. oleracea is a high salt-tolerant species that can tolerate a variety of salts found in soil. Therefore, P. oleracea may be considered a promising species for improving ecological balance in saline soils.
Boukhelouf W, SI-BACHIR A, Mezerdi F, Ghazi C, Saouache Y.
Sap beetles (Nitidulidae) of date palms of the Deglet Nour variety in the Ziban region (Algeria): distribution patterns and effectiveness of date bunch bagging. Agricultura Tropica et Subtropica [Internet]. 2024;57 (1).
Publisher's VersionAbstractThis study aims to update the list of Nitidulidae species observed on date palms in Algeria (Ziban region), their spatial dynamics according to the development stages (larva, pupa, adult), and the effectiveness of the bagging operation. In 2020, we sampled and examined 1800 dates of the Deglet Nour variety from three palm groves managed with different protection modes: yellow bagging, white bagging, and no bagging. The results obtained mention the presence of nine species of Nitidulidae with five species reported for the first time on dates in Algeria. The highest relative abundance (RA) of Nitidulidae beetles was noted in the southern (28%) direction. However, the variation of infestation rate (IR) according to the direction was not very accentuated. The GLM analysis showed that, except for the adult stage, the direction presented a highly significant effect on the RA variation of the total Nitudilidae, the larva and pupa stages (p < 0.0001), but there was no significant effect of direction on the IR in all studied cases. The highest RA of total Nitidulidae was found on the white plastic-protected dates (RA = 42%), the IR of the total Nitidulidae was higher on dates protected by yellow plastic (IR = 38%). The unprotected dates recorded the lowest RA and IR for all studied cases and the effect of bagging type on the RA variation of Nitidulidae, in all studied cases, was statistically highly significant (p < 0.0001). This effect on the IR was very highly significant only for total Nitudilidae, larvae, and adults (p < 0.0001). So, the southern direction presents the best conditions for sheltering the largest numbers of Nitidulidae. The latter also has a marked preference for bunches covered by plastic bags rather than for those left uncovered. This implies the ineffectiveness of the operation of protecting dates with plastic bags, especially the yellow-coloured ones.
Benzina I, Abdelkrim S-B, Arar A, Perennou C, GUELMAMI A.
Using DPSIR framework for the implementation of wetlands observatory: case study Sebkhates of Aures wetlands complex (Northerneast, Algeria). Anis GUELMAMI [Internet]. 2024;181 (1) :293-309.
Publisher's VersionAbstractWetlands are present within intricate ecological settings, exhibiting dynamic changes over time and across different areas with regard to their functional and structural diversity. Several approaches have been introduced for ecosystem analysis and management since 1990s, where Driver – Pressure – State – Impact – Response (DPSIR) framework is one of the widely used approaches for assessing and managing environmental problems. In this study, we proposed a DPSIR framework as a model in the Sebkhates of Aures wetland complex (SAWC, Northeast of Algeria), in order to create a regional wetland observatory to deliver ecosystem services within current state of changes resulted from socioeconomic drivers. DPSIR facilitates the identification of essential indicators to detect threats to the Sebkahtes of Aures wetlands complex (SAWC), influencing policymakers to enhance the protection and management of these wetlands. In line with the established DPSIR framework. This same approach and methodology could be applied to the other 15 wetlands complexes known in Algeria, culminating in the creation of a national wetland observatory. Furthermore, DPSIR can be employed as an analytical tool for policy making in the context of sustainable management of wetland ecosystems and can serve as a model in the establishment and development of various observatory programs in Algeria.
Benzina I, SI-BACHIR A, Arar A, Perennou C, GUELMAMI A.
Using DPSIR framework for the implementation of wetlands observatory: case study Sebkhates of Aures wetlands complex (Northerneast, Algeria). Present Environment and Sustainable Development [Internet]. 2024;18 (1).
Publisher's VersionAbstractWetlands are present within intricate ecological settings, exhibiting dynamic changes over time and across different areas with regard to their functional and structural diversity. Several approaches have been introduced for ecosystem analysis and management since 1990s, where Driver – Pressure – State – Impact – Response (DPSIR) framework is one of the widely used approaches for assessing and managing environmental problems. In this study, we proposed a DPSIR framework as a model in the Sebkhates of Aures wetland complex (SAWC, Northeast of Algeria), in order to create a regional wetland observatory to deliver ecosystem services within current state of changes resulted from socioeconomic drivers. DPSIR facilitates the identification of essential indicators to detect threats to the Sebkahtes of Aures wetlands complex (SAWC), influencing policymakers to enhance the protection and management of these wetlands. In line with the established DPSIR framework. This same approach and methodology could be applied to the other 15 wetlands complexes known in Algeria, culminating in the creation of a national wetland observatory. Furthermore, DPSIR can be employed as an analytical tool for policy making in the context of sustainable management of wetland ecosystems and can serve as a model in the establishment and development of various observatory programs in Algeria.
2023
Rebiai S, Merah E, Boubiche DE.
A novel comprehensive extension to BPMN language for security-aware two-tier security model and architecture of cloud applications. [Internet]. 2023;11 (2) :135-148.
Publisher's VersionAbstract
Enterprises have always given great importance to business process management to be competitive and profitable. With the advent of cloud computing, other opportunities are given to these enterprises to execute their business processes with minimal cost in a very short time. Business processes (BPs) are modelled using specific languages. BPMN is the most popular of these languages. However, its current version does not support process modelling for eventual execution in the cloud. Resource management, risk management, deployment, and security are key concepts in cloud computing that a modelling language must support. This paper presents an extension of the BPMN language for modelling business processes in the cloud, integrating the concept of security to secure cloud execution. The use of our new proposed architecture and models for secure BPs is illustrated by a real-life example that demonstrates how our extension is used to define/enforce actual security requirements.
Bensalem S, Boudjir I.
Les Verbalisations Métagraphiques : Quel Apport Pour La Compréhension Des Difficultés Orthographiques Des étudiants Universitaires ?. Qabas Journal of Studies Human and Social [Internet]. 2023;7 (3) :1108-1127.
Publisher's VersionAbstract
La verbalisation métagraphique, inspirée des entretiens d’explicitation de Vermersch (1991) favorise la métacognition. En effet, le scripteur est conduit à réfléchir à la fois sur la langue écrite comme objet d’étude et sur son propre fonctionnement. Ceci nous conduit à nous demander : Quelle méthodologie mettre en place afin d’accompagner les scripteurs, à savoir des étudiants universitaires dans le retour réflexif sur le fonctionnement de la langue ? Partant de l’analyse de verbalisations métagraphiques menées avec lesdits étudiants, nous postulons à ce titre, que l’accent serait mis sur une méthodologie qui pourrait être transposée dans le milieu institutionnel et ce, afin d’aider les scripteurs à expliciter leurs cheminements cognitifs voire, leurs choix orthographiques. Abstract: The metagraphic verbalization, inspired by Vermersch's explanatory interviews (1991), promotes metacognition. Indeed, the writer is led to reflect both on the written language as an object of study and on its own functioning. This leads us to ask ourselves: Which methodology should be set up to accompany the writers, namely university students, in the reflective feedback on the functioning of the language? Starting from the analysis of metagraphic verbalizations conducted with these students, we postulate that the emphasis would be placed on a methodology that could be transposed in the institutional environment in order to help writers to explain their cognitive processes or even their spelling choices.
Khier I.
L’intertextualité Du Personnage Révolté Dans : Archéologie Du Chaos (amoureux) De Mustapha Benfodil, La Morsure Du Coquelicot De Sarah Haidar, Et Le Festin Nu De William S Burroughs. The Journal of the Algerian Poetics Laboratory. 2023;8 (1) :389-398.
Abstract
Notre article est une étude littéraire qui s’articule autour d’une composante importante du texte littéraire ; le personnage romanesque. Ce concept que nous allons explorer dans trois textes : le Festin Nu de William Burroughs. La Morsure du Coquelicot de Sarah haidar, et Archéologie du Chaos (amoureux) de Mustapha Benfodil. Notre étude vise à rechercher le lien intertextuel, en l’occurrence le personnage révolté, entre les trois romans. Plusieurs renvois dans les deux textes algériens au texte américain, nous ont poussé à s’interroger sur ce lien qui pourrait les rassembler. Cette étude va être à la lumière des théories faites par Roland Barthes et Kristeva sur l’intertextualité, aussi les travaux de Philippe Hamon et Vincent Jouve sur le personnage romanesque.
Bensaad S, Louchene A.
Low-cost convolutional neural network for tomato plantdiseases classification. IAES International Journal of Artificial Intelligence (IJ-AI) [Internet]. 2023;12 (1) :162-170.
Publisher's VersionAbstract
Agriculture is a crucial element to build a strong economy, not only because of its importance in providing food, but also as a source of raw materials for industry as well as source of energy. Different diseases affect plants, which leads to decrease in productivity. In recent years, developments in computing technology and machine-learning algorithms (such as deep neural networks) in the field of agriculture have played a great role to face this problem by building early detection tools. In this paper, we propose an automatic plant disease classification based on a low complexity convolutional neural network(CNN)architecture, which leads to faster on-line classification. For the training process, we used more than one 57,000 tomato leaf images representing nine classes, taken under natural environment, and considered during training without background subtraction. The designed model achieves 97.04% classification accuracy and less than 0.2 error, which shows a high accuracy in distinguishing a disease from another.
سعاد بعوز, مفيدة بن حفيظ.
الذكاء الانفعالي عند التلاميذ الممارسين وغير الممارسين للأنشطة الرياضية الترويحية دراسة مقارنة بمتوسطة أحمد بوعكاز –صالح باي- سطيف. مجلة المقدمة للدراسات الانسانية و الاجتماعية [Internet]. 2023;8 (1).
Publisher's VersionAbstract
هدفت الدراسة الآنية إلى البحث عن إمكانية وجود فروق في الذكاء الانفعالي عند التلاميذ الممارسين و غير الممارسين للأنشطة الرياضية الترويحية، و اعتمدت دراستنا على عينة قدرها 84 تلميذا متمدرسين بمتوسطة أحمد بوعكاز –صالح باي- سطيف. و بعد معالجة المتغيرات نظريا اعتمدنا على المنهج الوصفي ذو التصميم المقارن ، موظفين مقياس الذكاء الانفعالي لصاحبه أحمد علوان الذي تم تكييفه في البيئة الجزائرية و بعد إجراء المعالجة الإحصائية الوصفية و الاستدلالية المتمثلة في المتوسط الحسابي و الانحراف المعياري و اختبار T)) لمجموعتين مستقلتين. وقد توصلت دراستنا إلى مجموعة من النتائج تقر بعدم وجود فروق بين التلاميذ الممارسين و غير الممارسين في جميع أبعاد الذكاء الانفعالي سواء معرفة الانفعالات، تنظيم الانفعالات، التعاطف و التواصل الاجتماعي.
Bouzaher H, Belkacem M-A.
Le Débat Onusien Sur Les Droits De L’enfant : Une Confrontation Discursive Orientée Par «une Question Argumentative ». Revue algérienne des lettres [Internet]. 2023;6 (2) :141-153.
Publisher's VersionAbstract
Le présent article met en jeu un objectif bien précis, celui de nous interroger sur le rôle des questions argumentatives et de cerner leurs relations avec l’évolution argumentative des thèmes mis en délibération onusienne. Le corpus d’analyse est un recueil de comptes rendus analytiques « textes officiels » qui ont été récoltés sur le site officiel des Nations Unies. Notre travail s’inscrit dans la conception de l’interaction argumentative telle qu’elle a été définie par Christian Plantin. Ce modèle s’accorde parfaitement avec une analyse du dialogue onusien. Dans ce travail nous visons à présenter le statut argumentatif et interactionnel de la question argumentative. This article brings in a very precise objective that allows us to interrogate the role of argumentative questions, and to identify their relations with the argumentative evolution of themes provided in the United Nations’ deliberation. The corpus of analysis is a collection of analytic reports “official texts”, which were collected from the UN’s official website. Our work falls under to the conception of argumentative interaction such as the one defined by Christian Plantin. This model corresponds perfectly with the UN’s dialogue analysis. In this work, we aim to present the argumentative and interactional statuses of argumentative questions.
Mehannaoui R, Mouss K-N, AKSA K.
IoT-based food traceability system: Architecture, technologies, applications, and future trends. Food Control [Internet]. 2023;145.
Publisher's VersionAbstract
An effective Food Traceability System (FTS) in a Food Supply Chain (FSC) should adequately provide all necessary information to the consumer(s), meet the requirements of the relevant agencies, and improve food safety as well as consumer confidence. New information and communication technologies are rapidly advancing, especially after the emergence of the Internet of Things (IoT). Consequently, new food traceability systems have become mainly based on IoT. Many studies have been conducted on food traceability. They mainly focused on the practical implementation and theoretical concepts. Accordingly, various definitions, technologies, and principles have been proposed. The “traceability” concept has been defined in several ways and each new definition has tried to generalize its previous ones. Nevertheless, no standard definition has been reached. Furthermore, the architecture of IoT-based food traceability systems has not yet been standardized. Similarly, used technologies in this field have not been yet well classified. This article presents an analysis of the existing definitions of food traceability, and thus proposes a new one that aims to be simpler, general, and encompassing than the previous ones. We also propose, through this article, a new architecture for IoT-based food traceability systems as well as a new classification of technologies used in this context. We do not miss discussing the applications of different technologies and future trends in the field of IoT-based food traceability systems. Mainly, an FTS can make use of three types of technologies: Identification and Monitoring Technologies (IMT), Communication Technologies (CT), and Data Management Technologies (DMT). Improving a food traceability system requires the use of the best new technologies. There is a variety of promising technologies today to enhance FTS, such as fifth-generation (5G) mobile communication systems and distributed ledger technology (DLT).
Abdessemed A-A, Mouss L-H, Benaggoune K.
BASA: An improved hybrid bees algorithm for the single machine scheduling with early/tardy jobs. International Journal of Production Management and Engineering [Internet]. 2023;11 (2) :167-177.
Publisher's VersionAbstract
In this paper, we present a novel hybrid meta-heuristic by enhancing the Basic Bees Algorithm through the integration of a local search method namely Simulated Annealing and Variable Neighbourhood Search like algorithm. The resulted hybrid bees algorithm (BASA) is used to solve the Single Machine Scheduling Problem with Early/Tardy jobs, where the generated outcomes are compared against the Basic Bees Algorithm (BA), and against some stat-of-the-art meta-heuristics. Computational results reveal that our proposed framework outperforms the Basic Bees Algorithm, and demonstrates a competitive performance compared with some algorithms extracted from the literature.
Malki M, Chatouh K.
Construction of linear codes over $\mathfrak{R}=\sum_{s=0}^{4} v_{5}^{s}\mathcal{A}_{4}$. MATHEMATICAL MODELING AND COMPUTING [Internet]. 2023;10 (1) :147–158.
Publisher's VersionAbstract
The aim of this paper is to propose a new family of codes. We define this family over the ring R=∑4s=0vs5A4R=∑s=04v5sA4, with v55=v5v55=v5. We derive its properties, a generator matrix and Gray images. This new family of codes is illustrated by three applications.
Saidani A, KALLA M, Bendib K.
The premise of a participatory management of urban space. Neighborhood associations: Commitment, militancy and challenge the case of the city of Batna, Algeria. GEOGRAPHY [Internet]. 2023.
Publisher's VersionAbstract
From the 1990s, urban policy in Algeria underwent significant upheavals, including authoritarian management, which was replaced by participatory management. Following the example of Algerian cities, the city of Batna adheres with this new vision, hence the implementation of a partnership program that involves various stakeholders including the citizen. The latter is present within multiple associations. The objective of this work is to highlight the activism of neighborhood associations as a representative element of civil society and their determining role in the management of different situations. To report on this issue, a field survey was conducted in the form of semi-directive interviews addressed to the three local actors: associations, citizens and elected officials.
Khatir A, Bouchama Z, Benaggoune S, Zerroug N.
Indirect adaptive fuzzy finite time synergetic control for power systems. Power Stations, Grids and Systems [Internet]. 2023;1.
Publisher's VersionAbstract
Introduction. Budget constraints in a world ravenous for electrical power have led utility companies to operate generating stations with full power and sometimes at the limit of stability. In such drastic conditions the occurrence of any contingency or disturbance may lead to a critical situation starting with poorly damped oscillations followed by loss of synchronism and power system instability. In the past decades, the utilization of supplementary excitation control signals for improving power system stability has received much attention. Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp low-frequency oscillations caused by load disturbances or short-circuit faults.
Problem. Adaptive power system stabilizers have been proposed to adequately deal with a wide range of operating conditions, but they suffer from the major drawback of requiring parameter model identification, state observation and on-line feedback gain computation. Power systems are nonlinear systems, with configurations and parameters that fluctuate with time that which require a fully nonlinear model and an adaptive control scheme for a practical operating environment. A new nonlinear adaptive fuzzy approach based on synergetic control theory which has been developed for nonlinear power system stabilizers to overcome above mentioned problems.
Aim. Synergetic control theory has been successfully applied in the design of power system stabilizers is a most promising robust control technique relying on the same principle of invariance found in sliding mode control, but without its chattering drawback. In most of its applications, synergetic control law was designed based on an asymptotic stability analysis and the system trajectories evolve to a specified attractor reaching the equilibrium in an infinite time. In this paper an indirect finite time adaptive fuzzy synergetic power system stabilizer for damping local and inter-area modes of oscillations for power systems is presented.
Methodology. The proposed controller design is based on an adaptive fuzzy control combining a synergetic control theory with a finite-time attractor and Lyapunov synthesis. Enhancing existing adaptive fuzzy synergetic power system stabilizer, where fuzzy systems are used to approximate unknown system dynamics and robust synergetic control for only providing asymptotic stability of the closed-loop system, the proposed technique procures finite time convergence property in the derivation of the continuous synergetic control law. Analytical proofs for finite time convergence are presented confirming that the proposed adaptive scheme can guarantee that system signals are bounded and finite time stability obtained.
Results. The performance of the proposed stabilizer is evaluated for a single machine infinite bus system and for a multi machine power system under different type of disturbances. Simulation results are compared to those obtained with a conventional adaptive fuzzy synergetic controller.
Hessad M-A, Bouchama Z, Benaggoune S, Behih K.
Cascade sliding mode maximum power point tracking controller for photovoltaic systems. Power Stations, Grids and Systems [Internet]. 2023;1.
Publisher's VersionAbstract
Introduction. Constant increases in power consumption by both industrial and individual users may cause depletion of fossil fuels and environmental pollution, and hence there is a growing interest in clean and renewable energy resources. Photovoltaic power generation systems are playing an important role as a clean power electricity source in meeting future electricity demands.
Problem. All photovoltaic systems have two problems; the first one being the very low electric-power generation efficiency, especially under low-irradiation states; the second resides in the interdependence of the amount of the electric power generated by solar arrays and the ever changing weather conditions. Load mismatch can occur under these weather varying conditions such that maximum power is not extracted and delivered to the load. This issue constitutes the so-called maximum power point tracking problem.
Aim. Many methods have been developed to determine the maximum power point under all conditions. There are various methods, in most of them based on the well-known principle of perturb and observe. In this method, the operating point oscillates at a certain amplitude, no matter whether the maximum power point is reached or not. That is, this oscillation remains even in the steady state after reaching the maximum power point, which leads to power loss. This is an essential drawback of the previous method. In this paper, a cascade sliding mode maximum power point tracking control for a photovoltaic system is proposed to overcome above mentioned problems.
Methodology. The photovoltaic system is mainly composed of a solar array, DC/DC boost converter, cascade sliding mode controller, and an output load. Two sliding mode control design strategies are joined to construct the proposed controller. The primary sliding mode algorithm is designed for maximum power point searching, i.e., to track the output reference voltage of the solar array. This voltage is used to manipulate the setpoint of the secondary sliding mode controller, which is used via the DC-DC boost converter to achieve maximum power output.
Results. This novel approach provides a good transient response, a low tracking error and a very fast reaction against the solar radiation and photovoltaic cell temperature variations. The simulation results demonstrate the effectiveness of the proposed approach in the presence of environmental disturbances.
Lahrech M-H, Lahrech A-C, Abdelhadi B.
Optimal Design of 1.2 MVA Medium Voltage Power Electronic Traction Transformer for AC 15 kV/16.7 Hz Railway Grid. Journal of the Korean Society for Railway [Internet]. 2023;26 (2).
Publisher's VersionAbstract
This paper deals with the design and optimization of a 1.2 MVA medium-voltage (MV) power electronic traction transformer (PETT) for an AC 15 kV/16.7 Hz railway grid, in which a simple two-stage multi-cell PETT topology consisting of a bidirectional 170 kW, 2.5 kV AC rms to 6 kV DC power factor corrected (PFC) converter stage followed by a bidirectional isolated 46 kHz, 6 kV to 1.5 kV series resonant DC/DC converter for each cell is presented. This paper presents a methodology that maximizes the converter"s efficiency and minimizes the converter"s size and weight. Accordingly, the first stage employs 10 kV SiC MOSFETs based on the integrated Triangular Current Mode (iTCM). The second stage uses 10 kV SiC MOSFETs on the MV-side, 3.3 kV SiC MOSFETs on the LV-side, and a medium frequency (MF) MV transformer operating at 46 kHz. MF transformers offer a way to reduce weight and improve energy efficiency, particularly in electric multiple-unit applications. The MF MV transformer requires power electronic converters, which invert and rectify the voltages and currents at the desired operating frequency. The development of high voltage SiC MOSFETs, which can be used instead of Si IGBTs in PETT topologies, increases the operating frequency without reducing the converter"s efficiency. The designed MV PETT achieves 98.95% efficiency and 0.76 kVA/kg power density.
Maoucha A, Ferhati H, Djeffal F, AbdelMalek F.
Highly efficient Cd-Free ZnMgO/CIGS solar cells via effective band-gap tuning strategy. Journal of Computational Electronics [Internet]. 2023;22 :887–896.
Publisher's VersionAbstract
This work proposes a new modeling framework based on combining graded band-gap (GBG) engineering and metaheuristic optimization to improve the Cd-Free ZnMgO/CIGS solar cell performances. Analytical and numerical calculations are carried out to assess the influence of band-gap profiles of both buffer and active layers on the electronic and optical properties of the studied solar cell. This investigation shows a great improvement of solar cell efficiency by increasing the optoelectronic figures of merit through tuning and optimizing the band-gap profiles and the conduction band offset at the ZnMgO/CIGS interface. Moreover, metaheuristic-based optimization models are developed to optimize the GBG profiles and enhance the optical and electrical performances of the solar cell. In this context, we recorded very satisfactory results, where the optimized design with GBG paradigm offers a high efficiency of 31.88% compared to 23.35% provided by the conventional CdS/CIGS solar cell. Therefore, this study provides a new strategy in enhancing the efficiency of thin-film solar cells by exploiting the graded band-gap engineering combined with metaheuristic optimization approach.