El-Oued University
  • Algiers, Wilaya d'El Oued , Algeria
Recent publications
Africa has seen an upsurge in diagnostic imaging utilization, with benefits of efficient and accurate diagnosis, but these could easily be offset by undesirable effects attributed to unjustified, unoptimized imaging and poor quality examinations. This paper aims to present Africa’s position regarding quality and safety in imaging, give reasons for the rising interest in quality and safety, define quality and safety from an African context, list drivers for quality and safety in Africa, discuss the impact of COVID-19 on quality and safety, and review Africa’s progress using the Bonn Call for Action framework while proposing a way forward for imaging quality and safety in Africa. In spite of a healthcare setting characterized by meagre financial, human and technology resources, a rapidly widening disease-burden spectrum, growing proportion of non-communicable diseases and resurgence of tropical and global infections, Africa has over the last ten years made significant strides in quality and safety for imaging. These include raising radiation-safety awareness, interest and application of evidence-based radiation safety recommendations and guidance tools, establishing facility and national diagnostic reference levels (DRLs) and strengthening end-user education and training. Major challenges are: limited human resource, low prioritization of imaging in relation to other health services, low level of integration of imaging into the entire health service delivery, insufficient awareness for radiation safety awareness, a radiation safety culture which is emerging, insufficient facilities and opportunities for education and training. Solutions to these challenges should target the entire hierarchy of health service delivery from prioritization, policy, planning, processes to procedures.
The main objective of this research is to obtain the best arrangement of new extended cylindrical iron fins that achieve the highest productivity of hemispherical solar distillers. To achieve this, extended cylindrical iron fins with a diameter of 1.2 cm were placed at various distances on the bottom basin of the hemispherical solar distiller (0, 1, 2, 3, 4, and 5 cm). To obtain the optimal distance between the extended cylindrical iron fins that achieve the highest productivity, three configurations of the hemispherical solar distillers were designed, tested, and compared in terms of performance. The first is a traditional hemispherical distiller, while the second and third are hemispherical distillers with extended cylindrical iron fins spaced at different distances. Experiments are carried out over three days and for a total of 12 h, for each day we tested two different distances and compare to the traditional hemispherical distiller at the same climate conditions. The experimental results showed that increasing the number of extended cylindrical iron fins increases the yield; that is, the best yield is obtained when the basin is completely filled with fins (0 cm). Furthermore, when compared to a traditional hemispherical distiller (4.80 L/m²/day), the cumulative yield of the hemispherical solar distiller with extended cylindrical iron fins at distances of 0, 1, 2, 3, 4, and 5 cm reached to 6.30, 6.10, 5.90, 5.65, 5.40, and 5.10 L/m²/day, respectively. These results presented that, the utilization of extended cylindrical iron fins represent the good option which improved the cumulative yield by 31.25, 27.08, 22.92, 17.71, 12.50, and 6.25% for a fins distance of 0, 1, 2, 3, 4, and 5 cm, respectively. These results showed that the use of extended cylindrical iron fins with zero distance represents the optimum configuration that achieves the highest productivity; in this case, the absorber surface after installing contiguous extended cylindrical iron fins is characterized as similar to the semi-circular corrugated surface.
Induction motors are susceptible to many types of faults that can become catastrophic and cause production stoppages. To predict emerging faults and avoid an unexpected failure, an induction motor can be diagnosed using the proposed motor current normalized residual harmonic analysis method. This method is simple and efficient. It is based on a more sensitive fault signature and a single frequency of the harmonic for the different faults. It is based also on the analysis of residual harmonics, which can be measured between the normalized linear fast Fourier transform spectrum of the healthy motor current and that of the faulty motor current. The proposed method can mitigate the task of the fault detection system by monitoring the occurrence of a residual harmonic fixed at a precise frequency. This study focuses on the rotor fault of broken bars and inter-turn short circuits in stator windings. In-depth experimental results demonstrate the rapid detection of different faults at the characteristic frequency of 50 Hz. It is not necessary to conduct a wide spectral sweep to search each time for different faults that have variable characteristic frequencies depending on the type of fault. This method can be useful for diagnosing other types of faults such as eccentricities, bearings and magnetic circuits.
Glasses with compositions (0.8-x)Sb2O3−0.2Na2O-(x)WO3-(0.0025) Er2O3, (0 ≤ x ≤ 0.4 mol) has been synthesized by the melt-quenching technique. Physical, optical characteristics and spectroscopy have been identified and investigated. As the glass composition changes, definite variations in physio-optical properties can be observed as well as the temperature of the glass transition (Tg), the density (ρ), molar volume (Vm), bandgap energy (Eg), and the refractive index (n). The Judd-Ofelt theory has been performed using a UV–VIS-NIR absorption spectrum to examine the compositional effect on Er³⁺ spectroscopic properties. Some basic spectroscopic parameters including electric dipole line strengths, Judd-Ofelt parameters, the rate of radiative probability, and the lifetime of radiative levels, are determined. A high NIR emission at 1.53 μm was observed when exciting glasses at 980 nm. The FWHM, the effective line-width (Δλeff), the emission cross-section (σem), and the gain bandwidth values were calculated using the theory of Füchtbauer–Ladenburg, and the findings were critically analyzed. the decay of fluorescence spectra for the ⁴I13/2 level was registered, and the lifetime for the studied glasses was calculated. Upconversion luminescence was observed in the green and red regions under 980 nm excitation, with a relative increase in emission intensity due to the added tungsten content. Based on the results obtained, the studied glasses are favorable materials for broadband amplifiers in WDM systems and optical devices.
This work is concerned with a full von Kármán beam in the presence of infinite-memory, Microtemperature and distributed delay terms. Firstly we establish the well posedness of the system. Secondly, by considered the kernel h : R + → R + satisfying h(t) ≤ ξ(t)H(h(t)), ∀t ∈ R + , where ξ and H are functions satisfying some specific properties, and under this very general hypothesis on the behavior of h at infinity, we prove the stability of the system.
Lobularia libyca (L. libyca) is a traditional plant that is popular for its richness in phenolic compounds and flavonoids. The aim of this study was to comprehensively investigate the phyto-chemical profile by liquid chromatography, electrospray ionization and tandem mass spectrometry (LC-ESI-MS), the mineral contents and the biological properties of L. libyca methanol extract. L. libyca contains significant amounts of phenolic compounds and flavonoids. Thirteen compounds classified as flavonoids were identified. L. libyca is rich in nutrients such as Na, Fe and Ca. Moreover, the methanol extract of L. libyca showed significant antioxidant activity without cytotoxic activity on HCT116 cells (human colon cancer cell line) and HepG2 cells (human hepatoma), showing an inhibition zone of 13 mm in diameter. In silico studies showed that decanoic acid ethyl ester exhibited the best fit in β-lactamase and DNA gyrase active sites; meanwhile, oleic acid showed the best fit in reductase binding sites. Thus, it can be concluded that L. libyca can serve as a beneficial nutraceutical agent, owing to its significant antioxidant and antibacterial potential and due to its richness in iron, calcium and potassium, which are essential for maintaining a healthy lifestyle.
Although the influence of fins on a basin's flat absorber will improve thermal performance and distillate production due to the increased heat transfer areas, many researchers are still interested in the problem of shading caused by fins, which reduces distiller productivity for some configurations of the fins designs. To obtain the best fin configurations that achieve the lowest shading effects and highest performance of hemispherical solar stills. The influences of absorbent cement layer with two types of fins (cylindrical and conical fins) with a diameter of 1.5 cm and a height of 3 cm at different gap spacing (3, 3.75, and 4.5 cm) were studied. To achieve these; three hemispherical solar stills were tested at same weather conditions, first is the conventional hemispherical still without fins (CHSWF) which represent the reference case. Second, is the cylindrical finned hemispherical still with gap spacing 3, 3.75, and 4.5 cm (CyFHS). Third, is the conical finned hemispherical still with gap spacing of 3, 3.75, and 4.5 cm (CoFHS). The results showed that, the cylindrical finned hemispherical still (CyFHS) productivity values are 5.55, 6.00, and 6.70 kg/m ² , respectively, while conical finned hemispherical still (CoFHS) productivity values are 6.20, 6.65, and 7.15 kg/m ² at gap spacing of 3, 3.75, and 4.5 cm, respectively compared to 4.20 kg/m ² that was produced by CHSWF. The results showed that the use of conical fins achieves the highest performance of hemispherical still as a result of reducing the effect of shading. Whereas, the best configuration that achieves the highest performance is the use of conical fins with a gap spacing of 4.5 cm, where the rate of improvement is 70.24% compared to CHSWF
Nowadays, cloud computing offers a digital infrastructure for smart city development. Cognitive cities are steadily automating daily urban processes. The ever expanding objective‐driven communities gather and share sensitive data that must be stored securely. Cloud computing offers a suitable platform that allows cognitive smart cities to access and re‐access data to learn from their past to adapt its current behaviour. However, the cloud is an untrusted entity that may expose data when decrypted for processing by systems. In this paper, we treat the issue of encrypted data processing. Often, the data is encrypted prior to transferring it to the cloud, where the cloud must have the data in clear to be able to make calculations which raises security and privacy threats if the cloud is considered untrusted. The scenario of asking users to make the calculations after decrypting the received cloud data and encrypting the obtained results before sending them back to the cloud is not a practical solution in distributed multi‐tenant architectures. Homomorphic encryption allows offers a solution for processing encrypted data. Many existing homomorphic encryption schemes suffer from limitations that hinder their usability. This paper presents an efficient fully homomorphic encryption scheme using twin key encryption and magic number fragmentation. The details of the scheme are presented along with cryptanalytic attacks to assess its effectiveness. The proposed scheme exhibits strong resilience against brute‐force attacks compared to its rivals from the literature. Finally, we illustrate the applicability of the proposed scheme using a cognitive smart city application.
Out of various moving average filter (MAF)-based phase-locked-loop (PLL), quasi type-1 PLL (QT1-PLL) is widely adopted due to its fast dynamic performance, implementation simplicity, and harmonics rejection abilities. However, the performance of QT1-PLL deteriorates in the presence of an off-nominal frequency unbalanced grid voltage component. Moreover, the sensitivity towards the fundamental frequency negative sequence (FFNS) component is high. Hence, this paper proposes a novel enhanced QT1-PLL solution that is insensitive to unbalance in the grid voltage signal during off-nominal frequency conditions. The proposed adaptive phase detector makes it possible to estimate both the fundamental frequency positive sequence (FFPS) and FFNS components with a high degree of immunity against harmonics. Notably, the pre-loop separation of the FFPS and the FFNS components helps suppress the second harmonic oscillations for improving the parameter estimation accuracy. The loop-filter design of QT1-PLL remains unaffected and requires a proportional gain to estimate the fundamental phase and frequency information. To address the DC offset issue, a modified delayed signal cancellation method is also proposed, which can theoretically eliminates the DC offset for any arbitrary delay length. A small-signal model of the proposed PLL is developed for the sake of stability analysis. Comparative results are provided
The aim of this study was to investigate the propensity of Roundup (RDP) to induce oxidative stress in the liver and brain of male Wistar rats and its possible attenuation by zinc sulfate. Rats were randomly divided into four groups: group I served as control rats, group II was treated with 269.9 mg RDP/kg bw administered in drinking water, group III rats have received Zn (277 mg/l) through oral way as zinc sulfate (ZnSO 4), and group IV animals were treated with RDP and Zn. The exposure of rats to RDP, during 30 days, caused the increase of the following serum hepatic markers: glucose, aminotransferases (ALT, AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), and total bilirubin (TB), along with reduced total protein content and albumin. Besides, this toxicity associated with an increase of lipid per-oxidation (malondialdehyde) and advanced oxidation protein product (AOPP). Also, the antioxidant defense system such as reduced glutathione (GSH), glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) in both the brain and liver is reduced compared with the control group, while the level of glutathione peroxidase (GPx) activity is increased. The treatment with zinc significantly restored the majority of these biochemical and oxidative stress parameters to normal levels, as well as improved the inhibition of AChE activity in the brain caused by RDP, thus emphasizing the protective potential of zinc in restoring the altered hepatic and cerebrum histoarchitecture. In conclusion, this study indicates that Zn protects against the toxicity of Roundup by providing hepatoprotective and neuroprotective effects.
The present study aims to improve the cumulative productivity of the hemispherical solar distillers by continuous distillation along the night and day with higher rates by designing and constructing innovative configurations. These innovative configurations were achieved by incorporating the higher thermal conductivity extended hollow cylindrical fins filled with the phase change materials (EHCF-PCM) in the basin of hemispherical solar distillers. To obtain the optimal configuration of EHCF-PCM that achieves the highest accumulative productivity, four different distances between the EHCF-PCM (0.0, 2, 3, and 4 cm) were studied. To investigate this idea, three configurations of hemispherical distillers were constructed, tested, and compared under the same Algerian climatic conditions. The first configuration is a conventional hemispherical solar distiller (CHSD) which represents the reference distiller, the second configuration is a hemispherical solar distiller with extended hollow cylindrical fins (HSD-EHCF), and the third configuration is a hemispherical solar distiller with extended hollow cylindrical fins filled with phase change materials (HSD-EHCF-PCM). The experimentation tests of the three distillers were conducted on four scenarios to test the four proposed distances between the EHCF-PCM, to obtain the best configuration that achieves the highest performance. The results showed that the utilization of the EHCF-PCM with zero gap distance represents the optimal configuration that achieves the highest performance of the hemispherical solar distillers. The utilization of the EHCF-PCM with zero gap distance (HSD-EHCF-PCM) gives accumulative productivity of 8.75 L/m²/day with an improvement of 80.4% compared to CHSD. Also, the utilization of EHCF-PCM with zero gap distance improved the daily efficiency from 39.6% for the CHSD to 71% for HSD-EHCF-PCM.
The ground air heat exchanger (GAHE) is a promising passive approach for cooling and heating buildings. In this study, thermal performance of helical ground air heat exchanger (HGAHE) has been experimentally assessed in summer season for arid climate. The findings revealed that, the outlet air temperature of the HGAHE is strongly dependent on the inlet air temperature. Furthermore, the air temperature drop and the heat exchange rate as high as 13.3 °C and 463.4 W respectively, are attained at the highest inlet temperature of 41.0 °C. Besides, a transient numerical model was established and validated through the experimental data to investigate the heat penetration into the borehole. The results acknowledge that, the borehole temperature distribution in axial direction is higher at the upper surface and then decreases with the HGAHE length. In the other hand, the borehole temperature distribution in the radial direction reduces rapidly with the distance away from the pipe surface. Moreover, when the ambient air temperature during the night shift is lower than the borehole temperature, the forced convection which helps to take the heat away via purge air circulating into the HGAHE pipe allowed the borehole to restore its cooling ability.
Low‐cost biochar adsorbents were prepared from pineapple peel waste (PPW) via hydrothermal carbonization (HTC) for CO2 capture. The effects of hydrothermal carbonization temperature (160–220 °C), retention time (2–8 h), and heating rate (5–30 °C min‐1) were studied. The hydrochar samples were further carbonized at 600 °C to produce pineapple peel biochar adsorbents. The carbon samples were characterized using Brunauer‐Emmett‐Teller (BET) analysis, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The effects of CO2 concentration in the feed, adsorption temperature, and feed flowrate on adsorption capacity were investigated in a fixed‐bed column adsorption system. The experimental data were analyzed using pseudo‐first order and pseudo‐second order kinetics, and Avrami equation. The best fits were inspected using the non‐linear regression coefficient, r2. The optimum adsorption capacity was obtained at 200 °C and 2 h at a heating rate of 5 °C min‐1. CO2 uptake capacity at 2.04 mmol·g‐1 was observed at 30 °C and 1 atm. The CO2 adsorption capacity of this system was increased with increasing CO2 feed concentration and decreased with increasing temperature and feed flowrate. The Avrami kinetics model was best fitted to the experimental data. The CO2 adsorption performance of PPW biochar (PPW‐BC) in a fixed‐bed column was successfully predicted by the Thomas and Yoon‐Nelson models based on the comparison of r2 values. Based on these results, the prepared PPW‐BC adsorbents could be a viable option for CO2 capture because they were synthesized from a low‐cost biomass source and are environmentally benign.
This work aims to optimize the antibacterial activity of iron oxide nanoparticles (IONPs) against both Gram-positive and Gram-negative bacteria. IONPs were greenly biosynthesized using Moringa oleifera leaves extract, and surface methodology (RSM) based on central composite design (CCD) was employed to investigate the combined effect of various experimental factors on the antibacterial activity of IONPs. The reaction and annealing temperatures besides precursor concentration were set as independent variables, while the antibacterial activity was set as a response to obtain the optimal conditions that maximizes IONPs antibacterial activity. Different characterization techniques such as UV–Vis, FTIR, XRD, SEM, and EDX were employed to study the properties of the biosynthesized nanoparticles. Meanwhile, the antibacterial activity was tested using the disk diffusion method. The characterizations results have confirmed the biosynthesis of Hematite (α-Fe2O3) nanoparticles of rhombohedral structure. The generated model has exhibited predicted values very close to the actual proving its validity to analyze and optimize the studied process. The model indicated that all the investigated parameters and their interactions have significantly affected IONPs antibacterial activity. An optimal antibacterial activity was achieved when biosynthesis factors at their lower levels (− 1). Furthermore, the effect of IONPs size on the antibacterial activity was studied and the results shown that the latter is significantly related to the nanoparticles size.
In this study, successfully investigated the biosynthesis of cupric oxide (CuO) and cuprous oxide (Cu2O) nanoparticles using Moringa oleifera aqueous leaves extract. The effect of pH on the formation of copper oxide nanoparticles, the optical properties, and free radical scavenging activities was studied. The obtained nanoparticles were characterized using UV-Vis, FTIR, XRD, and SEM techniques. UV-Vis spectra showed a peak with strong absorption at 275 nm for copper oxide with a direct bandgap of 2.59–2.65 eV and an indirect bandgap of 1.74–1.87 eV. FTIR analysis revealed two distinct absorption bands at 511 and 528 cm−1, which showed the successful production of copper oxide nanoparticles. The average crystallize size of copper oxide nanoparticles was 18–26 nm. It is clear from SEM images that CuO/Cu2O NPs have, in general, a spherical morphology with particle sizes less than 80–100 nm. Interestingly, the prepared CuO/Cu2O NPs showed high free radical scavenging activities.
Four magnetite nanoparticle (NP) samples have been greenly synthesized using four aqueous plant extracts, which are Artemisia herba-alba (L), Rosmarinus officinalis (L), Matricaria pubescens (L), and Juniperus phoenicia (L). The pH of these extracts are acidic (5.25, 5.05, 4.63, and 3.69, respectively). The synthesized samples were characterized by XRD, SEM, ATR-FTIR, and UV-Vis. This work aimed to study the preferential and enhanced adsorption of methyl green (MG) on the four greenly synthesized Fe3O4 surfaces by coupling three processes: MG adsorption in ambient dark conditions as the first process, followed by the thermocatalysis of the MG/Fe3O4 residual solution in the second process, and finally photocatalysis by the UV irradiation of MG/Fe3O4 residual solution after carrying out thermocatalysis. The novelty of this study lies in highlighting the influence of the mediating plant extract’s acidity on the magnetite NPs’ physicochemical characteristics, which impact the preferential and enhanced MG adsorption. The studied physicochemical characteristics are the functional hydroxyl group density on the magnetite surface, grain size, and band gap energy. It was found that the plant extract’s acidity has a clear effect on the studied physicochemical properties. The analysis of the FTIR spectra showed that the hydroxyl group densities differ on the four magnetite samples. Furthermore, the calculated grain sizes of the magnetite samples based on XRD spectra data vary from 29.27 to 41.49 nm. The analysis of the UV-Vis spectra of the four magnetite samples showed that the estimated direct band gap energies vary from 2.87 to 2.97 eV. The obtained results showed that the decrease of the mediating plant extract’s acidity leads to an increase in the hydroxyl group density on magnetite surfaces, which resulted in an increase in the MG adsorption capacities and yields in the first process of adsorption. Thus, MG adsorption was more preferred on greenly synthesized magnetite surfaces mediated by plant extracts with low acidity (Artemisia herba-alba (L) and Rosmarinus officinalis (L)). Furthermore, the increase of the plant extract’s acidity leads to a decrease in the particle size and an increase in the band gap energy and, therefore, to the decrease of the electron/hole pair recombination speed upon electron excitation. So, magnetite greenly synthesized from a more acidic mediating plant extract showed higher thermo- and photocatalytic activities for MG adsorption (Juniperus phoenicia (L) and Matricaria pubescens (L)). However, under photocatalysis, the enhancement is even more significant compared to thermocatalysis.
This work describes the use of XRD, SEM, and infrared spectroscopy in the evaluation of iron oxide nanoparticles as produced from three distinct plant extracts. The efficacy of the nanoparticles in terms of dye sorption was assessed using Congo Red (CR) and Evans Blue (EB) dyes. The research revealed that the synthesis method influences the properties of nanoparticles, which leads to different levels of effectiveness when it comes to sorption. The proposed sorption mechanism was founded on several characterization studies. Moreover, it was discovered that sorption might occur due to pores or binding groups rather than only an electrostatic connection. The results show that the nanoparticles' sorption effectiveness is heavily pH dependent. The produced nanoparticles showed potential for application in water treatment technologies due to the synthetic technique relative ease and the possibility of a low-cost catalyst.
Biosynthesis of antioxidant nanoparticles using plant extracts is a simple, rapid, environmentally friendly, and cost-effective approach. In this study, in vitro antioxidant copper mixed oxide nanoparticles (CuO/Cu2O) were prepared from the alcoholic extract of Phoenix Dactylifera L. and different aqueous concentrations of CuSO4·5H2O. The composition, crystallinity, morphology, and particle size of CuO/Cu2O NPs were tuned by increasing the CuSO4·5H2O concentration from 4 to 10 mM. Ultraviolet–visible (UV–Vis) and Fourier-transform infrared (FTIR) spectroscopy confirmed the reduction of CuSO4·5H2O and the formation of the CuO/Cu2O NPs. X-ray diffraction (XRD) confirmed the crystalline nature of the CuO/Cu2O NPs with a crystallite size varying from 18 to 35 nm. Scanning electron micrographs (SEM) showed that the CuO/Cu2O NPs have a spherical morphology with particle sizes ranging from 25 to 100 nm. The best antioxidant CuO/Cu2O NPs have a phase ratio of about 1:1 CuO/Cu2O with a half-maximal inhibitory concentration (IC50) of 0.39 mg/ml, an iron-containing reducing antioxidant power (FRAP) of 432 mg EFeSO4/100 mg NPs, and a total antioxidant capacity (TAC) of 65 mg EAA/gNPs. The results suggest that the synthesized CuO/Cu2O NPs are excellent antioxidants for therapeutic applications. Graphical abstract
Spices in general owned a very important reputation in the herbal plantae Kingdom; they have been used for food flavoring, preservation, aroma, and coloring for more than 2000 years. Moreover, spices are classified as all natural, and for this reason, they attracted a large scale of consumers worldwide; however, since most of spices are consumed in their natural form (without grounded them), it is necessary to monitor their consumed quantities. Hence, the aim of this work was to quantify major and trace elements contained in some Algerian kitchen frequently used spices (Piper nigrum L., Nigella sativa L., and Pimpinella anisum L.). Spice materials were washed well then pass through an instrumental neutron activation analysis (INAA). Results revealed the existence of twenty-six elements among them: K, Ca, Fe, and Na which showed significant concentrations, consecutively, while Ce, Eu, Lu, Sm, and Tb were presented at low concentrations. Furthermore, these spices consumption assessment results were found to be well below the tolerance limits compared with the recommended values (RDA) suggested by the FAO association.
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1,356 members
Abdelkrim Rebiai
  • Department of Chemistry
Abdelkader Laouid
  • Department of Computer Science
Lejdel Brahim
  • Computer science departement
F. Rehouma
  • Physics
Information
Address
BP 789 Poste centrale d'El Oued, 39000, Algiers, Wilaya d'El Oued , Algeria
Head of institution
Prof. Omar FERHAT
Website
www.univ-eloued.dz
Phone
+213 32120740/41
Fax
+213 32120736