Department of Material Sciences

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A computational study of the inclusion of β‑cyclodextrin and nicotinic acid: DFT, DFT‑D, NPA, NBO, QTAIM, and NCI‑RDG studies
(Journal of Molecular Modeling, 2020) Houdhaifa R. Belhouchet; Tahar Abbaz; Amel Bendjedou; Abdelkrim Gouasmia; Didier Villemin
Forming complexes with cyclodextrins can protect nicotinic acid (vitamin B3) from premature metabolism and enhance the solubility and stability of this drug. In this work, the formation of the inclusion complex of the neutral form of nicotinic acid and β-cyclodextrin was achieved. The complex is modeled using PM3, PM6-D4H3, and PM7, by considering two orientations of the guest: A and B, one is from wide to narrow rim, and the second is from narrow to the wide rim ,respectively. The global minima positions were re-optimized using three density function methods: MN-15, B3LYP, and PW6B95-D3 with polarized Pople basis set 6-31G(d) in gas and aqueous phase. Orientation A showed the minimum complexation energy where the carboxylic functional group of nicotinic acid is located on the primary hydroxyl rim of β-cyclodextrin and the pyridine ring is totally embedded in the cavity. To further our study on the nature of complexation and the interactions of this host–guest system, different calculations were done. The reactivity indices showed that orientation A is harder than B and more electrophilic; the charge transfer occurred from the host to the guest and was confirmed by the natural population analysis (NPA). The natural bond orbitals (NBO) reveal the delocalization of orbitals between the host and the guest, quantum theory of atoms in molecules (QTAIM) analysis, and non-covalent interaction (NCI) analysis based on a reduced density gradient (RDG) give a detailed description of the nature of interactions between the host and the guest such as the hydrogen bonding and van der Waals interaction, and confirmed the stability of the complex given by the orientation A.
Adsorption of Benzoic and Salicylic Acids Using Sodium and Intercalated Bentonite in Aqueous Solution
(American Scientific Publishers, 2016) Nadia Bensid; Yamina Berredjem; Zhour Hattab; Ridha Djellabi; Ouahida Khiereddine; FarhiHailaimia; Pierre Magri; Ahmed Boulmokh
The aim of this study was to apply a local betonite (Algeria) purified and intercalated with a surfactantnamely dodecyltrimethylammonium bromide (DTMAB) as an adsorbent to remove benzoic acid (BA) and salicylic (SA) which could be present in wastewaters. This intercalation process leads to improve the porous texture of materials that allows adsorbing efficiently organic compounds. The effect of various experimental parameters was investigated using a batch adsorption technique. The equilibrium adsorption data were well described by the Freundlich and Langmuir isotherms. The adsorption kinetics of both acids could be considered as pseudo-first order with internal diffusion.The capacity of DTMA–bentonite for Benzoic acid and Salicylic acid was found to be around 5 and 3.5 times respectively higher than that of Na–bentonite at 45 C. The thermodynamic study showed that the adsorption is not spontaneous and endothermic.
Adsorption of hexavalent chromium by crushed brick: effect of operating parameters and modeling study
(Desalination and Water Treatment, 2018-08-12) Assia Allaoui; Zhour Hattab; Radia Zerdoum; Yamina Berredjem; Ridha Djellabi; Wahiba Bessashia; Kamel Guerfi
The sorption of hexavalent chromium in aqueous solution using crushed Brick was carried out in batch mode. Powder of crushed Brick was prepared within a size between 500 and 800 μm. The crushed Brick was characterized by Fourier Transform infrared spectra (FTIR), BET surface area, X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM),X-ray diffraction (XRD), Thermogravimetric analysis (TGA)and Zeta Potential. The results showed that the crushed Brick is a typical aluminosilicate mineral with SiO2/Al2O3 ratio of 3.65. On the other hand, it has a surface area of 20.11 m2 g−1 and exhibits a net microporosity with a medium pore width of 2.26 Å. Batch experiments were conducted to study the effect of different operating parameters such as contact time, pH, stirring speed, temperature, adsorbent dose and initial Cr(VI) concentration on the adsorption of Cr(VI) by crushed Brick. The results showed that the maximum adsorption capacity was 3.06 mg g−1 at pH 3, adsorbent dose of 20 g L−1 and initial Cr(VI) concentration of 10 mg L−1. Furthermore, the adsorption capacity increases in an acidic medium until it reaches pH 3 and afterwards it decreases due to the different speciation of hexavalent chromium with pH shifting. The equilibrium data were analyzed using three isotherm models such as Langmuir, Freundlich and Temkin by linear method. A satisfactory correlation coefficient value of the Langmuir isotherm demonstrates that the hexavalent chromium adsorption by crushed Brick is monolayer physical adsorption. The kinetic studies showed that the experimental data were best describing by pseudo- second-order model and intra-particle diffusion. It was observed from the values of thermodynamics parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), that the nature of adsorption is non-spontaneous, exothermic and reflects the decreased randomness at the solid/solution interface during the adsorption.
Adsorption of metribuzin herbicide on raw maghnite and acid-treated maghnite in aqueous solutions
(Desalination and Water Treatment, 2018-11-20) A. Bettayeb; B.A. Reguig; Y. Mouchaal; M.A. Yahiaoui; M.M. Chehimi; Y. Berredjem
This study aims to examine the potentialities of raw maghnite and acid-activated maghnite (raw- Mag and Mag-H+) for Metribuzin herbicide removal from aqueous solutions. Raw-Mag and Mag-H+ were characterized using various analytical techniques such as NMR, BET, FTIR, FRX, ATD and SEM. The effect of various operating parameters such as contact time, Metribuzin concentration, pH, and adsorbent dose were investigated using raw-Mag and H-Mag in batch adsorption system. The results showed that the maximum adsorption capacity was 70.1 and 55.6 mg/g for raw-Mag and Mag-H+ respectively at pH 2.5, initial Metribuzin concentration of 20 mg/L, adsorbent raw-M and Mag-H+ dosage of 0.5 and 0.2 g/L . The adsorption of Metribuzin herbicide was important in acidic medium for both adsorbents. Furthermore, the adsorption uptake was found to be increased with increase initial concentration. The equilibrium adsorption data were well described by Freundlich and Langmuir isotherms. The kinetic studies showed that the experimental data was best describing by pseudo second order model. The Mag-H+ had above 30% adsorption uptake capacity after four regeneration cycles, this was higher than Raw-Mag. It was observed from the values of thermo- dynamics parameters such us Gibbs free energy (∆G°), enthalpy (∆H°), and entropy (∆S°), that the nature of adsorption is spontaneous
Analyse qualitative de quelques édulcorants
(2024) Abd El Hak Chibouni
Food is the first medicine, and excessive sugar consumption causes irreversible damage. Scientists have advised us to control our sugar intake, and sweeteners are foodstuffs endowed with sweetening power. They are used to keep the taste sweet, reduce the energy load, reshape the glycemic index, and replace sucrose for better longterm diet compliance. HPLC/ESI-MS UV Visible is the most reliable method for simultaneously determining 7 artificial sweeteners, including aspartame, saccharin, acesulfame-K, neotame, sucralose, cyclamate, alitame and a natural sweetener. --------------------------------------------------------------------------------------- الغذاء هو الشكل الأول للدواء، والإفراط في تناول السكر يسبب أضرارًا لا يمكن علاجها. وقد نصحنا العلماء بالتحكم في تناولنا للسكر، والمحليات هي أطعمة ذات قوة تحلية. وهي تسُتخدم للحفاظ على الحلاوة، وتقليل استهلاك الطاقة، وإعادة تشكيل مؤشر نسبة السكر في الدم واستبدال السكروز لتحسين الامتثال للنظام الغذائي على المدى الطويل. تعُد HPLC/ESI-MS مع الرؤية بالأشعة فوق البنفسجية هي الطريقة الأكثر موثوقية لتحديد 7 محليات صناعية في وقت واحد، بما في ذلك الأسبارتام والسكرين والأسيسولفام- ك والنيوتاموالسكرالوزوالسيكلاماتوالأليتام والمُحلي الطبيعي. --------------------------------------------------------------------------------------- L'alimentation est la première des médecines, et la consommation abusive de sucre provoque des dommages irréversibles. Les scientifiques ont conseillé de contrôler notre consommation en sucre, et l'édulcorants sont des denrées douées d'un pouvoir sucrant. Ils sont utilisés pour garder le gout sucré, diminuer la charge énergétique, remodeler l'index glycémique, et remplacer le saccharose pour une meilleure conformité du régime a long terme. L'HPLC/ESI-MS À UV Visible est la plus fiable à déterminer simultanément 7 édulcorants artificiels, notamment l'aspartame, la saccharine, l'acésulfame-K, le néotame, le sucralose, le cyclamate, l'alitame et un édulcorant naturel.
Analyses chimiques de quelque médicaments ayant le même effet thérapeutique
(2023) Abdelhalim DEGHBOUCHE
The objective of our work is the use of the Uv-vismethode for the quality of a drug widely used by the population having as active molecule paracetamol We analyzed the qualitative measures of drugs (paralgan.efferalgan.panadol) containing paracetamol and different exipients We found that some lost molecules comprising the nitrogen which are normally found in paracetamole also because we noticed that what is found on the calibration has nothing to do with the analyzer of the sample analyzer The methode is simple and honorable because it is valide ---------------------------------------------------------------------------- الهدف من عملنا هو استخدام طريقة مطيافية الاشعة فوق البنفسجية لجودة الدواء المستخدم على نطاق واسع من قبل السكان الذين لديهم جزيء نشط من الباراسيتامول قمنا بتحليل المقايس النوعية للادويةparalgan.efferalgan.panadolالتي تحتوي على الباراسيتامول ومركبات مختلفة وجدنا ان بعض الجزيئاتالمفقودة التي تشتمل على النيتروجين والتي توجد عادة في البراسيتامولايضالاننا لاحظنا ما هو موجود في المعايرة لا علاقة له بمحلل محلل العينة الطريقة بسيطة وغير مكلفة لانها صالحة جدا ---------------------------------------------------------------------------- L’objectif de notre travail est l’utilisation de la méthode UV –VIS pour la qualité d’un médicament très utilisé par la population ayant comme molécule active le paracétamol . Nous avons analysé les mesures qualitatives des médicaments (paralganefferalganpanadol) contiennent du paracétamol et différantsexipient . Nous avons trouvé que certains perdu certaines molécules comportant l’azote qui se trouve nourmalement dans le paracétamol aussi parce qui nous avons remarqué que ce qui trouve sur l’étalonnage na rieu avoir avec analyseur de l’echantillon analyser. La méthode est simple il faut juste la valide
Analysis of the effect of residual stresses on the reliability of a welded structure
(2024-02-21) ZEGHIDA Chouaib
Residual stresses, those that persist within materials devoid of external influences, play a pivotal role in dictating the fatigue life of mechanical structures. These stresses, emerging predominantly from material deformation heterogeneities, often have profound implications for the performance and longevity of components, especially in industries such as boiler-making and pressure vessels. Welding, an assembly process extensively utilized in these sectors, induces thermomechanical constraints at the joint, a consequence of the techniques and temperatures involved. The crux of evaluating residual stresses lies in its potential to forecast admissible stress levels during the design phase, allowing for optimized structure sizing and the assessment of specialized stress treatments' efficacy. This research stems from an established theme within our team, focusing on the intricate study of pre-cracked mechanical structures, specifically emphasizing stainless steel subjected to complex stresses. The overarching objective of the research is encapsulated in its theme: "Forecast/evaluation reliable performance of structural mechanical systems and optimal mechanical design." Through an in-depth exploration of welding dynamics and the resulting residual stresses, the study offers insights into the nuanced interplay between welding techniques, material properties, and subsequent structural behavior. The findings are instrumental in providing guidelines for enhanced design strategies, paving the way for more resilient and efficient welded structures in practical applications. This extensive study thoroughly examines the intricacies involved in welding operations, with a specific emphasis on butt joints in austenitic pipes. Utilizing FEA, the study illuminated the impact of welding sequences on residual stresses and associated distortions. Emphasis was placed on the potential of multi-pass welding in enhancing joint strength and producing microstructures with reduced residual stresses. The research also explored innovative stress mitigation techniques, namely the IHSI and MSIP, underscoring their efficacy in combating stress-related vulnerabilities in welded structures. --------------------- الاجهادات البقائية، تلك التي تظل داخل المواد دون وجود تأثيرات خارجية، تلعب دورًا حاسمًا في تحديد عمر التعب للهياكل الميكانيكية. هذه الضغوط، التي تنشأ بشكل رئيسي من تفاوتات تشوه المواد، غالبًا ما تكون لها تأثيرات عميقة على الأداء وطول عمر المكونات، خاصة في صناعات مثل صناعة الغلايات وأوعية الضغط. اللحام، وهو عملية تجميع تستخدم على نطاق واسع في هذه القطاعات، يؤدي إلى قيود ميكانيكية حرارية في المفصل، نتيجة لتقنياتاللحام وتزايد درجة الحرارة. ويكمن جوهر تقييم الاجهادات البقائية في قدرته على التنبؤ بمستويات الإجهاد المسموح بها خلال مرحلة التصميم، مما يسمح بتحديد حجم الهيكل الأمثل وتقييم فعالية علاجات الإجهاد المتخصصة. تنبع هذه الأبحاث من موضوع معروف ضمن فريقنا، يركز على الدراسة المعقدة للهياكل الميكانيكية التي تم فحصها مسبقًا، مع التركيز بشكل خاص على الفولاذ المقاوم للصدأ الذي يخضع لضغوط معقدة. الهدف العام للبحث ملخص في موضوعهالمتمثل في: "توقع / تقييم الأداء الموثوق للأنظمة الميكانيكية الهيكلية وتصميم ميكانيكي مثالي." من خلال دراسة عميقة لعمليات اللحام والاجهادات البقائية الناتجة، توفر الدراسة رؤى حول التفاعل الدقيق بين تقنيات اللحام، وخصائص المواد، والسلوك الهيكلي التالي. تعتبر النتائج مفيدة في توفير مبادئ توجيهية لاستراتيجيات التصميم المحسنة، مما يمهد الطريق لهياكل ملحومة أكثر مرونة وفعالية في التطبيقات العملية. هذه الدراسة الشاملة تفحص بعناية تامة التعقيدات المتعلقة بعمليات اللحام، مع التركيز بشكل خاص على الوصلاتاللحامية في الأنابيب الأوستنيتية. باستخدام FEA، أضاءت الدراسة تأثير تسلسلات اللحام على الاجهادات البقائية والتشوهات المرتبطة بها. تم التركيز على إمكانية اللحام متعدد التمريرات في تعزيز قوة المفصل وإنتاج الهياكل ذات الاجهادات البقائية المنخفضة. كما استكشف البحث تقنيات مبتكرة لتحسين الضغط، وهي IHSI وMSIP، مركزا على فعاليتهما في مكافحة الضعف المرتبط بالاجهادات في الهياكل الملحومة. -------------------- Les contraintes résiduelles, celles qui subsistent à l'intérieur des matériaux en l'absence d'influences extérieures, jouent un rôle crucial dans la détermination de la durée de vie à la fatigue des structures mécaniques. Ces contraintes, résultant principalement d'hétérogénéités de déformation du matériau, ont souvent des implications profondes pour la performance et la longévité des composants, en particulier dans des industries telles que la chaudronnerie et les récipients sous pression. La soudure, un processus d'assemblage largement utilisé dans ces secteurs, induit des contraintes thermomécaniques au niveau du joint, conséquence des techniques de soudage et l’évolutions de températures. L'essence de l'évaluation des contraintes résiduelles réside dans son potentiel de prévoir les niveaux de contraintes admissibles lors de la phase de conception, permettant une optimisation de la taille de la structure et l'évaluation de l'efficacité des traitements de contrainte spécialisés. Cette recherche issue d'un thème établi au sein de notre équipe, se concentrant sur l'étude complexe des structures mécaniques pré-fissurées, mettant spécifiquement l'accent sur l'acier inoxydable soumis à des contraintes complexes. À travers une exploration approfondie de la dynamique de soudage et des contraintes résiduelles résultantes, l'étude offre des éclairages sur l'interaction nuancée entre les techniques de soudage, les propriétés des matériaux et le comportement structurel subséquent. Les résultats sont essentiels pour fournir des lignes directrices pour des stratégies de conception améliorées, ouvrant la voie à des structures soudées plus résilientes et efficaces dans des applications pratiques. Cette étude approfondie examine minutieusement les complexités des opérations de soudage, en mettant particulièrement l'accent sur les joints bout à bout dans les tuyaux austénitiques.En utilisant la FEA, l'étude a éclairé l'impact des séquences de soudage sur les contraintes résiduelles et les distorsions associées. L'accent a été mis sur le potentiel de la soudure multi-passe pour renforcer la résistance des joints et produire des microstructures avec des contraintes résiduelles réduites. La recherche a également exploré des techniques innovantes d'atténuation des contraintes, à savoir l'IHSI et le MSIP, soulignant leur efficacité pour combattre les vulnérabilités liées aux contraintes dans les structures soudées.
Analysis, Design and Optimization of Multilayer Antenna Using Wave Concept Iterative Proces
(2017-09) Houda Amri
The wave concept iterative process is a procedure used for analyses a planar circuits This method consists in generating a recursive relationship between a wave source and reflected waves from the discontinuity plane which is divided into cells. A high computational speed has been achieved by using Fast Modal Transform (FMT). In this paper we study a patch antenna and multilayer circuits, to determine the electromagnetic characteristics of these structures.
Anti-corrosion performance of dehydroacetic acid thiosemicarbazone on XC38 carbon steel in an acidic medium
(2023-06-03) Boukerche Said
Antioxidant and Anticholinesterase Effects of Methanol Extract, And Consecutive Fractions of Peganum harmala L.
(Egyptian Journal of Chemistry, 2022-10-29) Amel NAIT MARZOUG; Fadila KHALDI; Adel AYARI; Lynda GALI; Abdelhak GHEID
Peganum harmala L. is a medicinal plant growing in the region of Sidi Fredj of Souk Ahras city (Northeastern of Algeria), whose native populations commonly used this plant to treat various health conditions and illnesses. Up to now, no previous study on the beneficial effects of P.harmala in the Souk Ahras region has been conducted. Therefore, the present study aimed to investigate the phenolic and flavonoid composition, as well as the antioxidant activities of the methanol extract and its three fractions: chloroform, ethyl acetate and butanol from seeds of P. harmala using eight different methods. The inhibitory effect of the extracts against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) was also determined. The results showed that the ethyl acetate fraction contained the highest amounts of total phenolic and total flavonoid (237.23±1.06 μg GAE/mg and 82.58±0.03 μg QE/mg, respectively). Important antioxidant activity was exerted by the extracts, especially the ethyl acetate fraction, which was the most effective. However, a weak antioxidant activity in Ferrous ions chelation was observed for all extracts with >800 μg/mL. The samples showed also a strong inhibitory effect against AChE and BChE, the chloroform fraction was the most potent with IC50 values of 14.69±0.10 μg/mL against AChE and 7.36±0.77 μg/mL against BChE comparable to that of galantamine. Conclusively, the obtained results proved the beneficial antioxidant and anticholinesterase activities of P. harmala-derived bioactive molecules.
APPLICATION OF STATISTICAL METHODS TO THE STUDY OF THE SPATIO-TEMPORAL EVOLUTION OF THE PHYSICO-CHEMICAL PARAMETERS OF THE SURFACE WATERS OF THE CHERF WADI BASIN. ALGERIA
(Journal of Fundamental and Applied Sciences, 2021-04-27) M. A. Bellazi1, 1*, 2, 1,1; N. Zenati; N. Belahcene; Y. Berredjem; A. E. Gheid
The physico-chemical parameters of the surface waters of the Cherf wadi watershed experience considerable variations over space and time under the influence of natural or anthropogenic phenomena. The application of the Kruskal-Wallis test for the comparison of the physico-chemical parameters showed that there were very significant intersite differences for pH, electrical conductivity, bicarbonate, chloride and sodium; as well as significant differences between the dates for all the studied variables. The typology highlighted by principal component analysis and Hierarchical Classification Analysis is linked to the availability of mineral elements by the anthropic activities of variable intensity depending on the sites, is added a natural process of mineralization related to the contact water- rock and throughfall phenomena. Statistical processing also revealed two types of water. The first type represents waters with very strong mineralization with very high sodium and chloride values characterizing the waters of site 5. The second type is marked by strong mineralization with high contents of Calcium. It characterizes the sites receiving discharges coming respectively from certain agglomerations not connected to the wastewater system and from the treatment plant.
Assessment and Modeling of Adsorption Capacity of a Cationic Dye on the Natural Silica of El-Aouanajijel in North-Eastern Algeria.
(Annals of R.S.C.B., 2021-01-01) Guerfi Samia; Filali Naima; Deghfel Nadir; Berredjem Yamina; Hattab Zhour
The aim of this work is to study the adsorption of basic dye, methylene blue (MB), from an aqueous solution onto natural silica. The adsorption of MB by natural silica was carried out in static mode. Effects of parameters such as mass of adsorbant, initial dye concentration, stirring velocity, temperature, and pH on adsorption were investigated. In order to study the mechanism of the adsorption process, three kinetic models including pseudo-first order, pseudo-second order, and intra-particle diffusion were used. In addition, the linear Langmuir and Freundlich models were applied to describe equilibrium isotherms. The experimental results of adsorbent/adsorbate equilibrium show that the adsorption was well described by the kinetic model of pseudo-second order and by the Langmuir adsorption isotherm model. Optimal conditions for the adsorption of MB by natural silica were found to be: Va = 200 rpm, T = 25°C, and pH = 8.
Bio/KOH ratio effect on activated Biochar and their dye based wastewater depollution
(Journal of Analytical and Applied Pyrolysis, 2022) F. Abbaci, A. Nait-Merzoug, O. Guellati, A. Harat, J. El-Haskouri, J. Delhalle, Z. Mekhalif and M. Guerioune
Waste potatoes peels (WPP) were adopted as a Biomass in this investigation to produce highly porous activated Biochars. The carbonized-activation process was principally governed on double pyrolysis at 600 ◦C intercalated by intermediate thermal-chemical step for homogenous incorporation of KOH oxidation agent. The effect of CWPP/KOH precursors ratio and the second pyrolysis temperature were systematically carried out to study the activated Biochars physico-chemical properties (morphology, textural and chemical bands) using different techniques (XRD, FTIR, Raman, TGA/DTA, XPS, FESEM, EDX, CHNO/S, BET, Zeta potential). The obtained activated Biochars are in micro/nano-porous systems and have interesting SSA [580 – 2400 m2/g], pore volume [0.08 – 1.02 cm3/g] and average pores size < 4 nm depending to the activation conditions. Moreover, the second pyrolysis temperature has an effect on the carbon atoms structure reorganization which is proved through their high Raman and textural properties. To demonstrate the double activation process effectiveness and the resulting Biochars properties, we have studied their adsorption behavior to remove two kinds of dyes (cationic MB and anionic AZ). The obtained adsorption capacities have reached 1246 mg/g and 315 mg/g with an equilibrium contact time around [5–10 min] and [30–40 min] for MB and AZ dyes, respectively. These values have never been reported before, especially using the very low activated Biochar adsorbent quantity of 8 mg (at each initial pH and 100 mg/l concentration of each dye solution).
Calcul ab initio des propriétés diélectriques de CdSe.
(2022) Nor El houda Guergah
We present an ab initio calculation of the dielectric properties of cadmium selenide (CdSe) in wurtzite structure, using a density functional perturbation theory (DFPT). Our calculations were carried out by means of ABINIT code. In this work, the dielectric constant and Born effective charge of CdSe in wurtzite structure have been calculated. Furthermore, the behavior of these two properties under pressure has been studied. ----------------------------------------------------------------------------------------------- نقدم حسابات باستخدام المبدأ الأول لحساب خواص العزل الكهربائي لسيلينيد الكادميوم ) CdSe ( في بنيته البلورية السداسية ) wurtzite ( إعتمادا على نظرية تابع الكثافة المثار) DFPT (. تم إجراء الحسابات باستخدام البرنامج الحسابي ) ABINIT .) في هذا العمل تم حساب ثابت العزل الكهربائي والشحنة الفعالة لبورن لسيلينيد الكادميوم) CdSe ( في بنيته البلورية السداسية) wurtzite (. كما قدمنا دراسة حول تأثير الضغط على هاتين الخاصيتين. ----------------------------------------------------------------------------------------------- Nous présentons un calcul de premier principe des propriétés diélectriques de séléniure de cadmium (CdSe) dans la structures wurtzite, en utilisant la théorie perturbative de la fonctionnelle de la densité (DFPT). Nos calculs ont été effectués à l’aide de code ABINIT. Dans ce travail, la constante diélectrique et la charge effective de Born du CdSe dans la structure wurtzite ont été calculés. De plus, le comportement de ces deux propriétés sous pression a été étudié.
Caractérisation des eaux souterraines de la wilaya de Souk Ahras
(2024) Ahlem Ahmed Nadji
Groundwater is a fragile resource. The permanent qualitative and quantitative management of this water remains an essential and perpetual subject. The Souk Ahras region is characterized by the presence of several underground aquifers. The methodology of the work consists in the physio-chemical characterization of the waters through the interpretation of physical parameters: electrical conductivity (µs/cm), T (C°), pH and chemical parameters: major and minor elements. The classification of these waters was carried out using chemical and multi-variable statistical methods (PCA) and an evaluation involving the SEQ-EAU. From the results, we note that Souk Ahras waters are of acceptable quality, with the exception of three boreholes (MD10 borehole, Ouled Abbes borehole and Dardarat spring) with high mineralization, which are often linked to the geological formation of the region. Generally speaking, the quality of Souk Ahras groundwater is potable. ------------------------------------------------------------------------------- المياه الجوفية مورد غير معتمد عليه وببقى التسيير النوعيوالكميالدائملهذه المياه موضوعاً أساسياً وحساساً. تتميز منطقة سوق أهراس بوجود العديد من جداول المياه الجوفية الشيء الذي جعل موضوع البحث يجذب انتباهنا. تعتمد منهجية العمل على التوصيف الفيزيوكيميائي للمياه من خلال تحليل الخصائص الفيزيائية : الناقلية الكهربائية, درجة الحرارة,pH والخصائص الكيميائية : العناصر الرئيسية والعناصر الثانوية.ومن خلال ماسبق ذكره، تصنيف هذه المياه باستخدام طرق كيميائية, وإحصائية متعددة المتغيرات (ACP) وتقييمها باستخدامSEQ_EAU . وفق نتائج التحاليل المتحصل عليها، نلاحظ أن المياه في ولاية سوق أهراس ذات نوعية مقبولة، باستثناء الثلاث آبار المتميزة بتمعدن عالي والتي غالباً ما ترتبط بالتكوين الجيولوجي للمنطقة. وبشكل عام، فإن نوعية المياه الجوفية في ولاية سوق أهراس صالحة للاستهلاك. ------------------------------------------------------------------------------- Les eaux souterraines constituent une ressource fragile. La gestion qualitative et quantitative permanent de cette eau reste un sujet essentiel et perpétuel. La région de Souk Ahras est caractérisée par la présence de plusieurs nappes souterraines. La méthodologie du travail consiste à la caractérisation physico-chimique des eaux par l’interprétation des paramètres physiques : conductivité électrique (µs/cm), T (C°), pH et les paramètres chimiques : éléments majeurs et éléments mineurs. La classification de ces eaux a été effectuée par des méthodes chimiques et statistiques multi-variables (ACP) et une évaluation en impliquant le SEQ-EAU. D'après les résultats, nous remarquons que les eaux de Souk Ahrassont de qualité acceptable, à l’exception de trois forages (forage MD10, forage Ouled Abbes et source Dardarat) ont une minéralisation élevéequi sont souvent liés à la formation géologique de la région. D'une manière générale, la qualité des eaux de la nappe de Souk Ahras est potable.
CARACTERISATION ET BIOFERTILISATION DES SOLS DE LA REGION DE SOUK AHRAS.
(2022) Iness Zidi; Amel Belkhir
This study is a contribution to the study of the effect of the incorporation of a bio-fertilizer (charcoal) on the physico-chemical properties of a soil and it is impact on these different characteristics. This study was carried out on two types of soil from two different regions of the wilaya of Souk Ahras, namely the region of Sedrata and the region of El khedara. The physic chemical analyzes carried out on the soil before and after application of elaborate charcoal are: the grain size, porosity, humidity, total limestone, organic carbon, organic matter, as well as pH and conductivity. The development of the material was based on potato peelings, which have undergone chemical activation according to a well-defined process at the LEREC -Annaba- laboratory level. Thus, the characterization of the material was carried out through the physico-chemical analyses: the humidity rate, the ash rate, the apparent density, the iodine number, the pH and the conductivity. As well as a structural characterization by Fourier Transform Infrared (FTIR); a morphological characterization by Scanning Electron Microscope SEM and elemental and textural analysis. The results obtained show that our material is porous, rich in organic matter, stores water, has functional groups and a large specific surface. It was concluded that after the application of the biofertilizer the soils became richer in matter organic, the high humidity proves that the material can be a reservoir of water. --------------------------------------------------------------------------------------------- تعد هذه الدراسة مساهمة في دراسة تأثير إدخال الأسمدة الحيوية )الفحم المنشط( على الخصائص الفيزيائية والكيميائية للتربة وتأثيرها على هذه الخصائص المختلفة. أجريت هذه الدراسة على نوعين من التربة من منطقتين مختلفتين بولاية سوق أهراس وهما منطقة سدراتة ومنطقة الخضارة، والتحليلات الفيزيائية والكيميائية التي أجريت على التربة قبل تطبيق الفحم النباتي وبعده وهي: المسامية، الرطوبة، الحجر الجيري الكلي، الكربون العضوي، المواد العضوية، وكذلك الأس الهيدروجيني والتوصيل. استند تطوير المادة على قشور البطاطا التي خضعت لتنشيط كيميائي وفقًا لعملية محددة جيدًا على عنابة وهكذا تم توصيف المادة المخصبة من خلال تحليلات فيزيائية وكيميائية: كمعدل – LEREC مستوى المختبر الرطوبة، معدل الرماد، الكثافة، مؤشر اليود، الرقم الهيدروجيني والتوصيل. وكذلك التوصيف الهيكلي الذي أنجز بواسطة مطياف الأشعة تحت الحمراء بالإضافة إلى التحليل التركيبي. أظهرت MEB وعن التوصيف المورفولوجي فكان عن طريق مسح المجهر الإلكتروني النتائج التي تم الحصول عليها أن مادتنا مسامية وغنية بالمواد العضوية وتخزن الماء ولها مجموعات وظيفية وسطح محدد كبير. وخلص إلى أنه بعد تطبيق الأسمدة الحيوية أصبحت التربة أكثر ثراءً في المادة العضوية، تثبت الرطوبة العالية أن المادة يمكن أن تكون خزانًا للماء. -------------------------------------------------------------------------------------------- La présente étude est une contribution à l'étude de l'effet de l'incorporation d'un biofertilisant (charbon actif) sur les propriétés physico chimique d’un sol et son impact sur ces différentes caractéristiques. Cette étude a été réalisée sur deux types de sols de deux régions différentes de la willaya de Souk Ahras à savoir la région de Sedrata et la région d’El khedara. Les analyses physico chimiques effectués sur les sols avant et après application du charbon élaboré sont : la granulométrie, la porosité, l’humidité, le calcaire total, le carbone organique, la matière organique, ainsi que le pH et la conductivité. L’élaboration du matériau été à base des épluchures de pomme de terre qui ont subi une activation chimique selon un processus bien défini au niveau de laboratoire LEREC -Annaba- . Ainsi la caractérisation du matériau a été effectuée par le biais des analyses physico chimiques à savoir : le taux d’humidité, le taux de cendre, la densité apparente, l’indice d’iode, le pH et la conductivité. Ainsi qu’une caractérisation structurale par Infrarouge à Transformée de Fourier (FTIR), une caractérisation morphologique par le Microscope Electronique à Balayage MEB et une analyse élémentaire et texturale. Les résultats obtenus montrent que notre matériau est poreux, riche en matière organique, stock l’eau, présente des groupements fonctionnels et une surface spécifique très importante et prometteuse. On a pu conclure qu’après l’application du biofertilisant que les sols sont devenus plus riches en matière organique et que le taux d’humidité important prouve que le matériau peut être un réservoir d’eau.
Caractérisation et Modélisation Electrique de Mini-Modules Photovoltaïques
(2023) Wiam YOUSFI
In this master thesis, we have explained how can we characterize and model photovoltaic cells/modules by performing current-voltage (I-V) and open-circuit voltage decay (OCVD) measurements. For this aim, we have developed experimental setups allowing the realization of these measurements as well as other measurements of temperature, humidity and solar irradiance. The obtained results were used (based on theoretical models) to extract characteristic parameters of the studied PV modules, namely, the carrier lifetime from OCVD measurements and the photovoltaic parameters from the I-V measurements (i.e. the short-circuit current Isc, the open-circuit voltage Voc, fill factor FF, efficiency η, saturation currents (Is1, Is2) and the respective ideality factors (n1,n2)). --------------------------------------------------------------------------------- في هذه المذكرة , قمنا بشرح كيفية توصيف ونمذجة الخلايا /الوحدات الكهروضوئية من خلال إجراء قياسات التيار والجهد (I-V ) وانخفاض جهد الدارة المفتوحة (OCVD). لهذا , الغرض قمنا خلال هذا العمل بتطوير تجهيزات تجريبية تسمح بتحقيق هذه القياسات بالإضافة إلى قياسات أخرى, موازية لدرجة الحرارة ,الرطوبة والإشعاع الشمسي . تم استخدام النتائج التي تم الحصول عليها (بالاستناد على النماذج النظرية ) لاستخراج المعلمات المميزة للوحدات الكهروضوئية المدروسة ,و هي عمر حاملات الشحنة من خلال قياسات OCVD والمعلمات الكهروضوئية من خلال القياسات I-V (أي تيار الدارة القصيرةIcc , جهد الدارة المفتوحة Vco ,عامل الشكل FF وكفاءة التحويل η, تيارات التشبع وعوامل الإشباع المثالية على التوالي ). الكلمات المفتاحية : --------------------------------------------------------------------------------- Dans ce mémoire, nous avons expliqué comment peut-on caractériser et de modéliser les cellules /modules photovoltaïques en effectuant des mesures de courant-tension (I-V) et de décroissance de la tension en circuit ouvert (OCVD). Pou cela, nous avons développé, au cours de ce travail, des montages expérimentales permettant la réalisation de ces mesures ainsi que d'autres mesures, parallèles, de température, d'humidité et de l'irradiance solaire. Les résultats obtenu ont été utilisé (en s'appuyant sur des modèles théoriques) pour extraire des paramètres caractéristiques des modules photovoltaïques étudiés, à savoir, la durée de vie des porteurs de charge à partir des mesures OCVD et les paramètres photovoltaïques à partir des mesures I-V (c.-à-d. le courant de circuit court Icc, la tension de circuit ouvert Vco, le facteur de forme FF et rendement de conversion η, les courants de saturation et les facteurs d'idéalité respectifs).
Caractérisations des propriétés chimico-physiques des couches minces " NiO" pure et dopé déposées par technique de pulvérisation thermochimique
(2024) Ridha Boumedjane
Thin layers of chromium doped nickel oxide were applied at deferential percentages (0, 1, 3, 5 and 7%) on a thermochemical spray glass substrate containing nickel acetate and chromium acetate at a molar concentration of 0,05 mol/L (per solution). This work mainly aims to study the effect of doping on the chemical-physical properties of the thin films of Ni1-xCrxO fabricated from the semiconductor. Optical spectra indicated that Ni1-xCrxO thin films had a high transparency of 65% to 86% obtained at 5% in the visible wavelength range. The variation in the optical energy gap was limited between 3,80eV and 3,91eV, varying with the evolution of the dopant level. The Urbach energy variation was also limited to 255meV and 299meV. The Ni0, 97 Cr0,03 O thin film prepared with a doping rate of 3% has the lowest energy gap value and the highest Urbach energy value. X-ray diffraction (XRD) has also indicated that any prepared Ni1-xCrxO layer has a polycrystalline cubic structure. We also concluded that the average electrical conductivity of all layers is 2, 14*10-2 (Ω. cm)-1. ---------------------------------------------------------------------------------- تم ترسيب الأغشية الرقيقة من أكسيد النيكل المطعم بالكروم بنسب متفاوتة (0، 1، 3، 5، 7%) بنجاح على ركيزة زجاجية بتقنية الرش الكيميائي الحراري باستخدام أسيتات النيكل وأسيتات الكروم بتركيز مولي 0.05 mol/l لكل محلول. الهدف الرئيسي من هذا البحث هو دراسة تأثير التطعيـم على تغير الخصائص الفيزيائية للأغشية الرقيقة Ni1-xCrxO المصنعة لأشباه النواقل. أشارت الأطياف الضوئية أن للأغشية الرقيقة Ni1-xCrxO شفافية عالية من %65 إلى % 86 والتي تحققت عند التطعيم بنسبة 5% في المجال المرئي للأطوال الموجية. كان التباين في طاقة الفجوة الضوئية محصور بين 3.80eV و 3.91eVمتغيرة بتغير نسبة التطعيم. كما كان التباين في طاقة ايرباخ محدود بين 255meV و .299meVتمتع الغشاء الرقيق Ni0.97Cr0.03O المحضر بنسبة التطعيم 3% بأقل قيمة لطاقة الفجوة وأكبر قيمة لطاقة ايرباخ. كما أشار حيود الأشعة السينيةDRX أن جميع الأغشية المحضرة Ni1-xCrxO ذات بنية مكعبة متعددة البلورات. كما استخلصنا أيضا أن متوسط الناقلية الكهربائية لجميع الأغشية هي: 2.14*10-2(Ω.cm)-1. ---------------------------------------------------------------------------------- Nous avons appliqué des couches minces d'oxyde de nickel dopé par du chrome à des pourcentages déférents (0, 1, 3, 5 et 7 %) sur un substrat en verre pulvérisé thermochimique contenant de l'acétate de nickel et de l'acétate de chrome à une concentration molaire de 0,05 mol/L (par solution). Ce travail vise principalement à étudier l'effet du dopage sur les propriétés chimico-physiques des couches minces de Ni1-xCrxO fabriquées du semi-conducteur. Les spectres optiques ont indiqué que les couches minces de Ni1-xCrxO avaient une transparence élevée de 65% à 86% obtenue à 5% dans la gamme visible des longueurs d'onde. La variation de gap d'énergie optique a été limitée entre 3,80eV et 3,91eV, variant avec l'évolution du taux de dopant. La variation de l'énergie d'Urbach était également limitée à 255meV et 299meV. La couche mince Ni0, 97 Cr0, 03 O préparée avec un taux de dopage de 3% a la plus basse valeur gap d'énergie et la plus grande valeur pour d'énergie d'Urbach. La diffraction des rayons X (DRX) a également indiqué que toute couche Ni1-xCrxO préparée a une structure cubique polycristalline. Nous avons également conclu que la moyenne de conductivité électrique de toutes les couches est 2,14*10-2 (Ω. cm)-1.
Carbon Nanotube Catalytic Deposition Synthesis
(IEEE Journal, 2007) O. Guellati, A. Fonseca, W. Bounour, M. Guerioune, Z. Mekhalif, Joseph Delhalle, A. Benaldjia and Jànos B. Nagy
Carbon nanotubes "CNTs" have been the focus of numerous investigations because of their unique and superior properties that are a consequence of their particular structure. Their synthesis has been receiving much attention for a wide variety of applications. Though, scientists are researching more economic ways to produce these structures with high quality and purity, our aim in this research is to investigate and optimize the results of the CNTs growth process using CCVD technique. Due to its simplicity and low cost, this technique is perfectly suited for the production of nanomaterials for future industrial applications. MWNTs CCVD synthesis was carried out at 700degC in 5 to 120 minutes reaction. It is essentially based on 2 steps process: a catalyst impregnation preparation step followed by CCVD procedure using ethylene decomposition over Fe-Co/MgO support. During this synthesis, impurities were also produced. Thus, subsequent chemical purification steps were required to separate the tubes. Finally, characterization of crude and purified products was performed by TEM, SEM and FESEM focusing on composition, form and purity obtained.
Chirped localized pulses in a highly nonlinear optical fiber with quintic non-kerr nonlinearities
(Results in Physics, 2022-10-07) Faissal Mansouri; Sassi Aouadi; Houria Triki; Yunzhou Sun; Yakup Yıldırım; Anjan Biswas; Hashim M. Alshehri; Qin Zhou
We study the existence and propagation properties of chirped localized pulses in a highly nonlinear fiber medium exhibiting self-steepening, self-frequency shift, and quintic non-Kerr nonlinearities. Pulse evolution in such fiber system is governed by a higher-order nonlinear Schrödinger equation incorporating the derivative Kerr and non-Kerr nonlinear terms. We show that bright, dark and kink type solitary waves exist in the presence of all physical processes. A special ansatz is introduced to analyze the existence of solitary waves on a continuous-wave background in the optical fiber medium. It is shown that the obtained localized pulses exhibit a nonlinear chirp which has a quadratic dependence on light intensity. We also find that the magnitude of the associated frequency chirp can be controlled effectively by varying the parameters of self steepening, self-frequency shift, and derivative non-Kerr nonlinearity effects. The restrictions on the optical fiber parameters are also extracted for the existence of these nonlinearly chirped solitary waves. Results in this study may be useful for experimental realization of shape-preserved pulses in optical fibers and further understanding of their optical transmission properties.