University of Ghardaia

We examine a quasilinear system of viscoelastic equations in this study that have fractional boundary conditions, dispersion, source, and variable-exponents. We discovered that the solution of the system is global and constrained under the right assumptions about the relaxation functions and initial conditions. After that, it is demonstrated that the blow-up has negative initial energy. Subsequently, the growth of solutions is demonstrated with positive initial energy, and the general decay result in the absence of the source term is achieved by using an integral inequality due to Komornik.

In this manuscript, we apply averaging theory to investigate the maximum number of limit cycles in a type of generalized Hill differential equation. that branch out from the periodic orbits of the linear center $\dot x = y,\dot y = - x.$ Here $\varepsilon > 0$ is a small parameter, \left( {\matrix{m \cr k \cr } } \right) = {{m!} \over {k!(m - k)!}}, P is a polynomial of degree n, and m is an arbitrary non-negative integer, and $\theta = \arctan (\frac{y}{x})$.

In this study, we investigate a nonlinear viscoelastic wave equation subject to acoustic boundary conditions and a nonlinear distributed delay feedback acting on the boundary. The asymptotic behaviour of solutions is analysed by considering a general kernel formulation and imposing suitable assumptions.

This work is concerned with a nonlinear viscoelastic wave equation with logarithmic nonlinearity. By supposing the nonlinear time-varying delay acting on the boundary feedback coupling by the acoustic and fractional boundary conditions. Firstly, we prove the exponential growth of solutions with negative initial-energy under suitable hypotheses and, in general, of the kernel. Then, the blow-up of solutions is showed under the same assumptions. This result extends and complements some previous results.

The goal of the present work was to investigate the interaction between endophytic bacterial isolates and Aspergillus flavus, with a specific focus on determining the occurrence of mutual antagonism upon contact. Aflatoxin B1 (AFB1) is a highly potent hepatic carcinogen produced by filamentous fungi. To decrease the amount of AFB1 in food products, nine strains of endophytic bacteria were evaluated for their efficacy in reducing AFB1 production; all of these strains were obtained from the roots of Stipa tenacissima L., an indigenous plant to the Algerian steppe. These endophytic bacterial isolates were selected as potential candidates due to their rapid growth. After a co-incubation period of 10 days in vitro, AFB1 analysis indicated that those nine isolates caused a decrease in AFB1 residual concentration by 10.04 to 98.44%, depending on the isolate. The two most efficient strains were ST01 and ST07, which showed 89.96 and 73.46% reduction of AFB1, respectively. The results of 16S rRNA gene sequencing revealed a strong genetic relationship between the two isolates and the species Acinetobacter calcoaceticus and Bacillus velezensis, respectively. These two isolates were subjected to characterization for their in vitro plant growth promotion (PGP) activity, including ACC-deaminase activity, IAA production, inorganic phosphate solubilization, and the production of siderophores and hydrogen cyanide. Based on the obtained findings, it is postulated that the aforementioned isolates hold potential as biofertilizers and biocontrol agents in combating AFB1 while posing a minimal danger to the ecological balance of microbial communities.

This study investigates the performance of hemispherical solar stills (HSS) enhanced with date kernels and olive kernels as heat storage materials to improve water distillation efficiency. By utilizing these natural and sustainable materials, the research highlights an alternative to synthetic options. Rigorous experimentation and detailed analysis under identical conditions reveal that both kernels significantly improve heat retention and water production rates. The HSS with date kernels (HSSDK) achieved a daily water productivity of 6.66 kg/m² day, representing an efficiency increase of 10.87%, while the HSS with olive kernels (HSSOK) produced 8.00 kg/m² day, enhancing efficiency by 13.54%. The cost per m³ of distilled water for HSSDK is approximately USD 4.65, while HSSOK costs USD 3.89, compared to USD 7.83 for the conventional CHSS system. These results demonstrate that the inclusion of heat storage materials has significantly reduced the cost of water production, with reductions of about 40% for HSSDK and 50% for HSSOK compared to the conventional system. These results are attributed to the high thermal conductivity and specific heat capacities of the kernels, enabling effective heat storage and gradual release. This study demonstrates the potential of agricultural by-products as cost-effective and sustainable solutions for solar water distillation. Further research is recommended to optimize the quantities and configurations of these materials, as well as to explore their integration with other renewable energy systems to enhance overall efficiency and sustainability.

Rainfall–runoff models are crucial tools for managing water resources. The absence of reliable rainfall data in many regions of the world is a major limitation for these models, notably in many African countries, although some recent global rainfall products can effectively monitor rainfall from space. In Algeria, to identify a relevant modeling approach using this new source of rainfall information, the present research aims to (i) compare a conceptual model (GR4J) and seven machine learning algorithms (FFNN, ELM, LSTM, LSTM2, GRU, SVM, and GPR) and (ii) compare different types of precipitation inputs, including four satellite products (CHIRPS, SM2RAIN, GPM, and PERSIANN), one reanalysis product (ERA5), and observed precipitation, to assess which combination of models and precipitation data provides the optimal performance for river discharge simulation. The results show that the ELM, FFNN, and LSTM algorithms give the best performance (NSE > 0.6) for river runoff simulation and provide reliable alternatives compared to a conceptual hydrological model. The SM2RAIN-ASCAT and ERA5 rainfall products are as efficient as observed precipitation in this data-scarce context. Consequently, this work is the first step towards the implementation of these tools for the operational monitoring of surface water resources in Algeria.

This study presents two groundbreaking achievements in materials science with significant implications for advanced technologies. First, we report the successful mechanosynthesis of Zn₂Ti₃O₈ through a solvent-free, solid-state reaction between rutile-type TiO₂ and ZnO, yielding the compound after 8 hours of milling. Second, we demonstrate a novel reverse phase conversion of TiO₂ from rutile to anatase under extreme conditions, involving a highly alkaline (KOH) environment at 160 °C, followed by hydrothermal treatment and calcination at 850 °C. This unprecedented transformation enhances the anatase phase’s morphological, optical, and surface properties, offering substantial advantages for various applications. Comprehensive characterization using X-ray diffraction, UV–Vis, and FT-IR spectroscopy revealed crucial insights into the materials' structural and optical properties. Notably, bandgap energies estimated from Tauc plots showed a systematic decrease with increasing reaction time, ranging from 3.54 to 3.49 eV for 2 to 10 hours, respectively. Our findings contribute significantly to the field by introducing an environmentally friendly Zn₂Ti₃O₈ synthesis route, challenging conventional phase stability understanding, and providing a method for precise bandgap control. This research not only advances fundamental knowledge but also opens new avenues for developing high-performance materials in energy and environmental applications, potentially revolutionizing next-generation technologies.

This study examines a wave equation within the framework of nonlinear viscoelasticity. Specifically, it considers a nonlinear, time‐varying delay feedback acting on the boundary, coupled with acoustic and fractional boundary conditions, and influenced by a logarithmic source term. Under suitable general assumptions on the kernel, we first establish the global existence of solutions and subsequently analyze their asymptotic behavior.

Solar cooking is considered an eco-friendly technology and an appropriate solution for cooking purposes, particularly in Saharan areas with abundant insolation. This work discusses the performance and behavior of a box solar cooker (BSC) that tested experimentally in three modes: solar mode, and in addition, was preheated using a resistive heater specifically in two modes electric, and solar-electric. Comparative tests were performed and temperatures were measured during the winter of January 2024 under the climatic of the Ghardaia region. The results of the experiments indicate that the maximum temperature of absorber tray reached in solar, electric and solar-electric mode was 124.428 ℃, 108 ℃, and 133, 68 ℃ and in addition, that the figures of merit F1, and F2, were obtained as 0.16 m2 ℃/w, 0.476, and efficiency was estimated by 40% and 42.7% respectively; in the case of using solar and solar electric mode. It also was noticed that cooking time can be reduced considerably when using the solar-electric mode.

This study examines the chemical composition, antioxidant properties, and urease inhibitory effects of Hyoscyamus muticus L. subsp. falezlez (Coss.) Maire. Using LC-ESI-MS/MS, 19 distinct phenolic compounds were identified, with chlorogenic acid being the most abundant. The ethanol extract demonstrated notable antioxidant activity, highlighting its potential for therapeutic use. Urease inhibition assays revealed a remarkable 91.35% inhibition by the H. muticus extract, with an IC50 value of 5.6 ± 1.20 μg/mL, indicating its promising role in addressing conditions linked to urease activity. Molecular docking studies further investigated the interaction between H. muticus phenolic compounds and urease, identifying hyperoside as a leading candidate, with a binding energy of −7.9 kcal/mol. Other compounds, such as rutin, luteolin, apigenin, kaempferol, hesperetin, chlorogenic acid, and rosmarinic acid, also demonstrated significant binding affinities, suggesting their potential to disrupt urease function. These findings highlight the therapeutic potential of H. muticus as a source of natural bioactive compounds, offering promising avenues for the development of novel treatments for urease-related disorders and oxidative stress.

Manufacturing Industries (MI) has developed in the past years, by including different types of machines such as the Rotating Machines (RM) to deliver High-Quality Products (HQP), however those machines are prone to failure, which effects on the production process and leading to high economic loses, the purpose behind this study is to present a new strategy that support’s the decision-making to avoid any unexpected breakdowns in the MI. A novel hybrid technique that combines the Adaptive Neuro Fuzzy Inference System (ANFIS), the Hybrid Whale Grey Wolf Optimizer (HWGO), and the state space (SS) approach using the Vibration Condition Monitoring (VCM) signals to determine the Remaining Useful Life (RUL) is introduced. The proposed approach was trained using features selected by the Decision Tree (DT) algorithm. A comparative analysis is conducted against the HWGO with 12 metaheuristic algorithms in terms of optimization. The SS model was applied for forecasting the future RUL values depending on the measured values by the ANFIS-HGWO. The overall results confirm the outperforming of the ANFIS-HWGO-SS compared to different contributions available in the literature using the PRONOSTIA database in terms of performance measure, Therefore, the ANFIS-HWGO-SS approach is a reliable tool for determining the RUL before any unexpected breakdown and further supports the decision-making by offering a vital timeframe for making the proper action before a failure occurs which can be applied for other machine-related tasks to ensure stability by decreasing the failure of the machine, reliability of the RM by providing HQP, security by avoiding accidents in MI, marking a significant step towards enhanced operational efficiency and sustainability.

Ophelimus maskelli (Ashmead, 1900) (Hymenoptera: Eulophidae) is an invasive species that has spread to Eucalyptus in the recent years in several countries, particularly in the Mediterranean and Africa, causing significant damage to Eucalyptus plantations and nurseries. The present work consists of, firstly, a study focussing on the incidence of infestation and the population dynamics of Ophelimus maskelli on Eucalyptus camalduliensis (Myrtaceae) and secondly, a study evaluating the parasitism of this pest by Closterocerus chamaeleon (Girault, 1922) (Hymenoptera) during two years (2019 and 2020) in two different forests in the region of Oued Smar (Algiers). The study revealed that the incidence of infestations is very high and Closterocerus chamaeleon , the parasitoid of Ophelimus maskelli used in several countries successfully, is present with a considerable rate of parasitism in the two sites; these results are discussed. This invasive species, which has spread in the recent years, requires further investigation in order to develop effective pest management methods that could possibly limit its spread.

In this work, two new hybrid control techniques combining Lyapunov theory (backstepping) and artificial intelligence (fuzzy logic type 1 and 2) have been developed for a wind energy conversion system (WECS) based on a double fed induction generator (DFIG). The main objective of this hybridisation is to ensure the adaptation of the gains in backstepping control by the regulators of type 1 and type 2, and to achieve instantaneous, precise, and continuous control of the active and reactive power exchanged with the utility grid by a doubly fed induction generator in a wind energy conversion system, our approach guarantees robustness and stability, ensuring high efficiency and optimal production quality of our WECS. In addition, an in-depth comparative study between these developed controllers is also the focus of this paper. The aim of this study is to compare the two new control techniques with the previously introduced backstepping control technique to highlight the performance of each. This comparative study is based on a series of tests during transient and steady-state operation of the system under the same conditions, namely, a qualitative comparison aimed at comparing response times and reference tracking capabilities; a quantitative comparison based on error and time as two important metrics that must be considered simultaneously; and, finally, a robustness comparison based on parameter variation of the system. The results obtained will show which of the two hybrid controllers is the best and most efficient in our system.

This study is concerned with a nonlinear viscoelastic wave equation. Assuming the nonlinear distributed delay feedback influences the boundary coupling through the acoustic boundary conditions. Under suitable assumptions and for the general case of the kernel, we prove the asymptotic behavior of solutions.

For ensuring a greener and low carbon future; renewable energies sources such as solar energy stands out as a prominent solution for generating sustainable and clean electricity due to its accessibility, abundance and numerous benefits. The use of solar panel also called as photovoltaic systems has more importance in the world for their ability to convert sun irradiation into electricity while they have significant drawbacks like the nonlinearity of Pv panel. The efficiency and performance of Photovoltaic (PV) systems can be influnced by various factors, like climate fluctuations during the day. Therefore, it is so important to optimize the power capturing from PV panels. To optimize the energy created by photovoltaic modules, it is necessary to carefully select a DC-DC converter with MPPT control. This guarantees that the maximum power is extracted from the solar power plant and sent to the demand side in less time and with greater effectiveness. This paper introduces a super twisting sliding mode control technique for achieving maximum power point tracking (MPPT) in a photovoltaic (PV) system. The Single Ended Primary Inductor Converter (SEPIC) is proposed as a superior alternative to the conventional boost dc-dc converter, as it enables the extraction of the highest possible power from the photovoltaic panels array. Upon doing a thorough comparison of the suggested control with the P&O algorithm in various scenarios using the MATLAB/SIMULINK tool, it was found that the provided STC (Synchronous Tracking Control) for the SEPIC converter demonstrates greater efficiency and reduced oscillation around the Maximum Power Point (MPP).

Sodium benzoate (E211) and potassium sorbate (E202) are two preservatives widely used alone or in combination in the food industry in Algeria. This study aims to estimate the dietary exposure of children and adolescents to these substances in Oran Province (Algeria) and to assess the risks incurred in consuming these two preservatives. For this, a total of 116 commercial food samples were analyzed for potassium sorbate and sodium benzoate content by HPLC, and a survey was carried out on 250 children and 765 adolescents using a consumption frequency questionnaire as the method. The concentration of preservatives in foodstuffs was mostly within the maximum permitted limits set by national and international standards. In scenario 2 and scenario 3, the estimated average dietary exposure to the two preservatives was below the ADI: it was 17–48% and 21–36% of the ADI for potassium sorbate and sodium benzoate, respectively. The dietary exposure at the 95th percentile exceeded the ADI for sodium benzoate and potassium sorbate when calculations were made using the average of samples containing these preservatives. The main contributors to exposure were carbonated drinks for sodium benzoate and juices, cheeses, and yogurts for potassium sorbate.

This study revisits the taxonomic classification of the genus Nocardiopsis through the application of advanced genome-based methodologies, representing a notable advancement beyond traditional approaches that primarily rely on 16S rRNA gene sequences and phenotypic traits. The advent of Next-Generation Sequencing (NGS) and sophisticated bioinformatic tools has enabled a more precise framework for prokaryotic classification. However, many recognized species still lack complete genome sequences. In this study, we employed overall genome-related indices (OGRI), particularly Average Nucleotide Identity (ANI) and digital DNA-DNA hybridization (dDDH), to reassess the phylogenetic relationships within the genus. Comparative analyses of complete 16S rRNA sequences demonstrated high genetic similarity between N. umidischolae 66/93 T and N. tropica VKMAc-1457 T (99.61% similarity), as well as between N. rhodophaea JCM15313T and N. rosea JCM15314T (100% identity). The dDDH, ANI%, FastANI%, ANIm, and ANIb values further supported these results, with 73.2%, 96.94%, 96.15%, 97.19%, and 96.74% for the former pair, and 93.6%, 99.13%, 99.97%, 99.98%, and 99.27% for the latter pair, respectively. All values surpassed the species delineation thresholds of 70% for dDDH and 95–96% for ANI. Consequently, we propose reclassifying N. umidischolae as a heterotypic synonym of N. tropica, and N. rosea as a heterotypic synonym of N. rhodophaea, in accordance with the International Code of Nomenclature of Prokaryotes (ICNP).

Swimming in the Sahara: a new locality record and range extension of Natrix maura (Linnaeus, 1758) (Squamata, Colubridae) from central Algeria. Natrix maura, commonly known as the viperine snake, is a widespread and common semi–aquatic species in the western Mediterranean region. This study reports a new locality record of N. maura from central Algeria, significantly extending the species' known range. Additionally, we provide an updated distribution map of N. maura in Algeria, compiled from a comprehensive dataset of occurrence records. Our findings emphasize the need for extensive herpetofaunal surveys in the country's underexplored regions.