Journal of New Technology and Materials

jntm

Description

“Journal of New Technology and Materials”(JNTM) is an international peer-reviewed journal that publishes high quality original works on the Material science s (physics, chemistry and life sciences) and engineering. It covers the aspect of materials science and engineering in all forms, particularly materials associated with new technologies (nanoscience and nanotechnology). JNTM provides a platform for researchers, students and industrialist to submit on-going research and developments in material and technology areas. Authors are solicited to contribute to the JNTM by submitting articles that illustrate research results and projects that describe significant advances in all areas covered by our scientific journal (JNTM). More informations are available on : https://sites.google.com/site/jntmjournal, ....... Citation on Google Scholar: https://scholar.google.fr/citations?user=bNBJ-50AAAAJ&hl=fr

8

Volumes

15

Numéros

182

Articles


Structural, Electronic and Magnetic Properties of quaternary Heusler compounds CoYFeZ and CoYMnZ (Z = Si, Ge, Ga and Al): An ab-initio Study

Torrichi Mohamed, 

Résumé: We have studied electronic and magnetic structural properties of Quaternary Heusler alloys CoYXZ where X is a transition metal with 3d electrons (X=Fe and Mn) and Z is the main group element (Z = Si, Ge, Ga and Al). These calculations have been carried out via ab-initio simulations based on density functional theory (DFT) approach. We have explored the most stable structure among these materials in three different atomic arrangements (type-1, type-2, type-3). The structural stability of these compounds has studied from the calculation of their cohesion energy. The type-1 structure is found energetically more stable. According to our study, the quaternary compound CoYMnGa and CoYMnAl proves to be a half-metal ferromagnetic with a total magnetic moment of 4μB. While the quaternary compounds, CoYMnGe and CoYFeZ (Z=Si, Ge and Ga) seem to be not ferromagnetic, with zero point magnetic. Whereas, CoYMnSi, CoYMnGe and CoYFeAl are found as a ferromagnetic with magnetic moment of 1.91μB, 2.90μB and 4.29μB respectively. In addition, it is also divulged that half-metallicity in these compounds is closely related to arrangements of magnetic atoms in the structure of the Heusler. The magnetization of the compounds CoYFeZ and CoYMnZ comes mainly from the 4d electrons the of Yttrium (Y) atom and the 3d electrons of the Fe and Mn atoms.

Mots clés: : Quaternary Heusler alloy, Half-metallic ferromagnetism, Electronic structures, Density functional theory.


A Hybrid Optimization Approach to Interaction Parameter Identification in thermodynamic model problems

Merzougui Abdelkrim,  Regabe Slimane, 

Résumé: The interaction parameter identification problem in thermodynamic models is an important requirement and a common task in many areas of chemical engineering because these models form the basis for synthesis, design, optimization and control of process. For bad starting values the use gradient based result in local optimal solutions. To overcome this drawback, a global optimization approach, Simulated Annealing(SA) and genetic algorithm(GA), has been coupled with a Nelder-Mead Simplex(NMS) method. To improve the accuracy of the interaction parameter estimate. The experimental ternary LLE data for extraction of 1-propanol from water with n-hexane were considered in the NRTL and UNIQUAC activity coefficient model. In conclusion, the different obtained results of the prediction of liquid–liquid equilibrium are compared. These results were obtained to justify that the process of optimization recommended is very practical to estimate the interaction parameters of this ternary system.

Mots clés: hybrid optimization approach, genetic algorithm, simulated annealing, parameter estimation


Numerical calculations of thermal-aerodynamic characteristics of a solar air duct with multiple V-shaped vortex generators

Menni Younes,  Azzi Ahmed,  Chamkha Ali. J., 

Résumé: Enhancement of Thermal-aerodynamic characteristics of air in a rectangular channel by inserting ꞌVꞌ-geometry obstacles is addressed. The steady equations governing the constant property incompressible Newtonian fluid flow and convective heat transfer in the channel, i.e., continuity, momentum and energy equations, are solved by the finite volume approach with the SIMPLE algorithm using a computational fluid dynamic technique (CFD). The effects of Reynolds numbers as well as ꞌVꞌ-obstacles’ attack angles are evaluated and analyzed numerically. Contours of axial and radial velocities, fields of dynamic pressure and temperature, profiles of axial velocity, local and average Nusselt Numbers, local and average friction coefficients, and pressure drop are obtained at constant surface temperature condition along the top and bottom channel walls. The present research ended up at interesting results which constitute a valuable contribution to the improvement of the knowledge basis of professional work through research related to turbulent-flow forced convection within channels supplied with obstacles, and especially inside heat exchangers and solar flat plate collectors. Future work will involve more complex geometries and using nanofluids to assess the optimum conditions for heat transfer enhancements.

Mots clés: turbulent forced convection flow ; solar air channels ; V-geometry obstacles ; CFD


The Effects of Electromagnetic stirring on Microstructure and Properties of γ-TiAl based Alloys Fabricated by Selective Laser Melting Technique.

Ismaeel Adam,  Cunshan Wang, 

Résumé: The γ-TiAl based Ti-Al-Mn-Nb alloys were fabricated by selective laser melting (SLM) on the TC4 substrate. The effects of electromagnetic on microstructure and properties of the alloy were investigated in detail. The results reveal that the alloy without electromagnetic stirring EMS consist of γ-TiAl phase with tetragonal structure and α2-Ti3Al phase with hcp structure, while the alloy with applied electromagnetic stirring EMS consist of γ-TiAl, α2-Ti3Al and α-Ti with hcp structure, and the morphological structure for the alloy without EMS exhibits near lamellar structure and the alloy with EMS shows duplex structure, the alloy without EMS shows higher microhardness and wear resistance, and the values decrease with applied EMS.

Mots clés: selective laser melting ; γ-TiAl based alloys ; microstructure ; properties ; electromagnetic stirring


AspenPlus based simulation for waste heat recovery in cement industries

رجب يوسف,  جرافي-كعباش ختيمة,  صاولي وسيل, 

Résumé: Cement manufacturing is a highly energy intensive process, which resulting a large loss of energy at the level of the different plants, in other way the loss of energy in the form of heat is very significantly at the level of the cooler. This work focus on direct waste heat recovery, where tertiary air was recovered to the preheater, for this study a process model of the preheater, the kiln, and the cooler is developed, using Aspen Plus simulation software, and the model is verified against measured data from industry. This paper presents the influence of the recovery of the waste heat and the natural gas feed on the clinker production and the energy consumption. Results show that the recovery of the tertiary air make the clinker production rise by about 30% and the energy consumption reduced by about 20%. The variation of the flow input value of the natural gas resulted in a positive relationship between natural gas flow and clinker production, and an inverse relationship between the natural gas feed and energy consumption. In the other hand the increase of the natural gas flow resulting an augmentation in the clinker production, and the reverse results for the consumption of energy.

Mots clés: waste ; heat ; simulation ; energy ; cement ; clinker


Distributed control and monitoring based on cooperating agents: an application for manufacturing system

شوحل وهيبة,  مهداوي رفيق,  موس ليلي حياة, 

Résumé: Control and monitoring of current manufacturing systems has become increasingly a complex problem. To expand their reliability we propose in this work a distributed approach for control and monitoring using the Multi Agents Systems. This approach is based on the decomposition of the complex system into subsystems easier to manage, and the design of several agents each one on these agents is dedicated to a particular task. A software application supporting this approach is developed for the cement clinker system of the Ain Touta cement plant. It is chosen to test the approach on real data. The results show that our distributed approach produces better results than the centralized health monitoring and control.

Mots clés: Distributed control ; MAS ; Distributed diagnosis ; health monitoring


Setting in suspension of double-walled carbon by some biopolymers: characterization by Turbiscan

Seffah Karima, 

Résumé: Our present study consists of the formulation and characterization of suspensions of double-walled carbon nanotubes (CNTs) using two biopolymers of natural origin (lecithin and proteins). Soy lecithin and sodium caseinate are two biodegradable and non-toxic biopolymers, they are widely used as an ingredient in the food industry. The operating conditions of dispersion such as the power and the duration of sonication as well as the dispersant/NTCs report/ratio, were optimized. Stability was demonstrated by the Turbiscan technique, and confirmed by zeta potential measurements over time. The Turbiscan has proven to be a non-invasive, efficient and convenient tool for analyzing the stability of CNTs suspensions.

Mots clés: biopolymère ; stability ; Turbiscan ; Double walled carbon nanotubes


A hybrid method based on CNNs and Edge-Based Active Contour Models for Medical Image Segmentation

أميرة بن داود,  فلة حشوف, 

Résumé: Edge-based active contour models have been one of the most prominent and influential approaches in image segmentation. It has been proven that they are very effective when they are applied on images with inhomogeneous intensity. Traditional edge-stop functions (ESFs) are usually used when edges are defined by the image gradient. They often produce weak edges because they fail to stop at the precise boundary. In this work, a new approach integrating machine learning algorithm with edge-based model using a level set method (LSM) is proposed. The ESF is constructed from a convolutional neural network. Then it is applied to an edge-based active contour model. The proposed method has been applied on medical images. Obtained results have been compared to those given by k-nearest neighbors and support vector machine to confirm the effectiveness of the proposed method.

Mots clés: Convolutional neural network ; edge-based active contour ; image segmentation ; medical images


Implementation of Sensorless SM-DTC with Conjoint Online Parameters Identification Based on MRAS

لقريوي سعيد, 

Résumé: The MRAS based on rotor flux integrated in the direct torque control (DTC-MRAS) is a very good solution in the speed estimation and control of the induction motor without speed sensor, the major problem with this theory is the machine parameters time-varying, which is causing the degradation of the performances and the stability of the drive. In this work, we aim to implement a DTC based on MRAS for rotor speed estimation and the joint online identification of stator resistance (Rs) and the inverse of rotor time constant (1/Tr). The proportional-integral regulators (PI) are used in the mechanism adaptation. Also, a sliding mode controller type is introduced in the speed control loop. For testing the performance and the stability of the proposed methods, an experimental setup is prepared with Simulink environment and the RTI blocs of the dSPACE card (DS1104).

Mots clés: DTC ; induction motor ; sliding mode ; patrameter estimation ; dsPACE


Study of the microstructural evolution of precipitation in AZ91 alloy

Azizi Assia,  Hamana Djamel,  Boumaza Leila,  Belamr Zahira,  Toubane Mehdia,  Medjemedj Warda, 

Résumé: Magnesium-based alloys have been the subject of several scientific research projects. Their excellent mechanical properties have allowed their use in various fields such as aeronautics and automotive. Phase transformations play a crucial role in the mechanical properties improvement; therefore the understanding of structural hardening due to the precipitation reaction is important. The main objective of this work is to study the influence of the aging temperature on the precipitation mechanism in AZ91 () alloy. It has been found that at high aging temperatures continuous precipitation is appeared and characterized by fine precipitates, however, discontinuous precipitation is observed under cellular form at low temperatures. With increasing ageing time continuous precipitates can be also observed and they block the growth of discontinuous precipitates. This phenomena influence directly the mechanical properties of such alloys, for that microhardness measurements are done to evaluate the mechanical properties variations as function of temperature, ageing time and so on.

Mots clés: AZ91 ; continuous and discontinuous precipitation ; aging ; hardening


ARTIFICIAL AGING EFFECT ON PRECIPITATION AND AGE-HARDENING IN AN AL-ZN-MG-CU ALLOY

Boumaza Leila,  Hadjadj Lakhdar,  Belamri Zahira,  Azizi Assia,  Benmelit Rabia,  Hamana Djamel, 

Résumé: In the present work, the influence of heat treatment on the mechanical properties and precipitation of the different phases in Al-Zn-Mg-Cu alloy was studied. The precipitation sequence and the mechanism of structural hardening have been followed using the differential scanning calorimetry (DSC), the microhardness measurements, the X-ray diffraction (XRD) and the scanning electron microscopy (SEM). Five calorimetric effects have been recorded and correspond to the different phases precipitating in this system of alloys and which are: the GPI zones and / or VRC (or GPII), the intermediate η' phase and the equilibrium η phase with a suspicion concerning the existence of T and S phases. Microhardness measurements of the aged state at 226 °C confirm the existence of two types of phases: the metastable η’ phase and the equilibrium η phase (MgZn2). The appearance of the first precipitates was followed by SEM. The fine precipitates become larger (holdings at 243 and 266 °C) and the equilibrium η phase continues to grow inside and on the grain boundaries to become a large spherical and/or lamellar precipitate. The X-ray diffraction confirmed that only the equilibrium η phase was observed in this type of alloy.

Mots clés: Al-Zn-Mg-Cu ; mechanical properties ; heat treatments ; DSC ; XRD ; and SEM


SURFACE QUALITY EFFECT ON TRIBOLOGICAL BEHAVIOR

بوحبيلة حمودي, 

Résumé: Abstract The surface quality for a given product is induced by the different factors involved in the process of cutting, and represented by the value of roughness. It is therefore necessary to define the influence of the surface state (the result of the turn cut) on the friction and wear behavior (dry) of the steel-steel pair under atmospheric conditions. To do this, tribological tests were carried out using a pin-cylinder tribometer (tracks, different roughness were machined and tested in contact with different metal pins), mounted on a lathe using of a device (realized) equipped with an acquisition software. Treatment and observations of the results were recorded using a profilometer, optical microscope, SEM and EDX. The results have increased the influence of the roughness, on the coefficient of friction (μ) which thus varies positively on the wear rate (W), which increases progressively by varying the surface state. We find a surface of the pin of hardness inferior (to the disk), plowed, cracked and plastically deformed, thus more loss of material by adhesion, oxidation of the formed particles compacted on the disk, from which a transfer of material and formation of the layer of metal oxide.

Mots clés: Keywords: Quality; Tribology; Behavior; Friction; Wear; Cutting;


New Trend in Enhancing Bearing Remaining Useful Life Prediction

بوكرة طاهر,  لبارود عبد السلام, 

Résumé: Generally the two main strategies taken in data-driven remaining useful life (RUL) prediction of a component/system can be summarized in 1) identifying a health indicator and predicting its trend until a predefined threshold; 2) mapping directly the health indicator (HI) to RUL by regression. Under the first category, traditional extracted features for RUL prediction usually show undesirable behaviors such as fluctuation, non-monotonicity and abrupt increase at the end which hampers the accuracy of the RUL prediction. To enhance the prediction accuracy, this paper brings a new feature selection method, based on preprocessing further the extracted features in a way that the identified prognostic feature results in an obvious trend quality. A set of established and proposed suitability metrics for the prognostic task are used to assess the identified features qualities. The Particle Filtering technique is adopted as a projection tool as well for the prediction of the RUL due to its capability to carry nonlinear systems in presence of non-Gaussian process/observation noise. Datasets from bearings run-to-failure experiments provided by FEMTO-ST Institute - IEEE PHM 2012 challenge- were used to validate our approach. A mean percentage error of 12.18% was achieved indicating that the model worked accurately and reliably on every tested bearing..

Mots clés: Health Index ; Prognostics and Health Management ; Particle Filtering ; Remaining Useful Life


Study of wear resistance in dry and lubricated regime of molybdenum coating obtained by thermal spraying

Idir Abdelhek,  Younes Rassim,  Mouadji Youcef,  Sadeddine Abdelhamid,  Bradai Mohand Amokrane, 

Résumé: Surface treatments and metallic coatings offer multiple functional specifities to protect all types of metallic materials as well as composites, it is possible to renovate or modify physical characteristics through a multitude of techniques. This activity increases durability, corrosion protection, electrical conductivity or sliding characteristics. This is a necessary step in the production process of many metal workpieces. This surface treatment is suitable for parts of all sizes (bolts, pylons, car doors, etc.). Surface treatments can also protect workpieces against various perils and recover worn surface losses. The general principle of thermal spraying is to melt feedstock materials and inject it under high pressure on the substrate surface. This technique is commonly used in many industrial sectors. The thermal spraying of feedstock materials, such as molybdenum, which is a transition metal, has a high elasticity modulus, a high melting point and better mechanical properties (the addition of a small amount of molybdenum promotes the hardening of the steel). Molybdenum surface treatments thus provide a form of protection for parts against certain tribological and electrochemical risks. Surface treatments with molybdenum coatings greatly improve the protection of mechanical pieces against the severity of surface degradation phenomena such as tribo-corrosion. In the present work, the main goal is to study the dry and lubricated wear behavior of a molybdenum coating deposited by wire-arc spraying technique on a mild steel substrate. The coatings were characterized the coatings was viewed by a scanning electron microscope (SEM), Vickers micro-hardness and wear resistance using a pin-disc tribometer (pin/graphite disc). The result obtained showed that the applied load is a factor influencing the mass loss of molybdenum deposits, which are subjected to a sliding speed of 1m/s and have a slightly higher wear resistance than the ones of coatings subjected to a sliding speed of 0.5m/s. This result is observed for the two regimes studied (dry and lubricated). Under dry conditions, we also noted that the self-lubricating properties of molybdenum coatings did not significantly reduce mass loss.

Mots clés: Wear ; spraying-arc ; Molybdenum ; Lubrication ; Micro-hardness ; Microstructure.


Effect of alloying element addition on the microstructural evolution and corrosion behaviour of Fe-30 at. % (Al + Cr) alloys.

بلعمري زهيرة,  حمانة جمال,  عزيزي اسيا,  بومعزة ليلى,  حداد اسماء, 

Résumé: Fe-Al and Fe-Al-Cr alloys have interest industrial and biomedical applications for their excellent properties. Two materials of nominal composition Fe-30 at. % Al and Fe-15 at. % Al-15 at. % Cr have been examined. The aim of this present work is: first, study the order-disorder transformations in these alloys. Second, the effect of partial substitution of Al by Cr in Fe matrix on the microstrutural evolution and corrosion behaviour of two iron-based alloys. DSC analyses, XRD, microhardeness measurements, SEM analyses and electrochemical measurements have been carried out. The obtained results show that during heating the studied alloys undergo order-disorder and disorder-order transformations. The presence of Cr influences the ordering process of the D03 ordered phase and also varies the microhardness of these materials. During corrosion test in salt water, the chromium oxide layer (Cr2O3) forms on the surface of Fe-15 at. % Al-15 at.% Cr alloy and also increases its corrosion resistance. It is necessary to remember that the formation of D03 ordered phase has an effect on the electrochemical parameters. These results are a good agreement with the published works.

Mots clés: order-disorder transition ; D03 ordered phase ; iron-based alloys ; corrosion


Comparative study of transistors electrical characteristics made in BICMOS technology

بن شيهب أسماء,  حوبار فريدة, 

Résumé: In this paper, a comparative study of two bipolar transistors realized according to the same BICMOS-0.35 technology, but with two different architectures (self-aligned and quasi-self-aligned) is presented. In each case, the type of material forming the base and the geometric differences existing between the two considered structures are taken into account. The simulation allowed us to demonstrate the interest in introducing germanium in quasi-self-aligned bipolar transistors. In addition, it has been found that in low and medium injection, the electrical characteristics of the self-aligned bipolar transistor deviate greatly from the experimental results. With the quasi-self-aligned architecture, this gap remains moderate. In strong injection, and in both types of transistors, the electrical characteristics are very close to those obtained experimentally. copyright 03.03.2019

Mots clés: Transistor ; Heterojunction ; BICMOS ; SiGe ; Modelling


Realization, experimentation and simulation of prototypes of synchronous reluctance machines

فارس رباحي,  عمار بن التونسي, 

Résumé: The objective of this work is an approach of design, experimentation and simulation of three prototypes of synchronous reluctance machines, SynRM. After a state of research for this type of machines with interesting performances and applications, we have, for a first approach and following constraints of means of realization, opted for massive rotor topologies. The theoretical study as well as the mathematical model of the SynRM made it possible to identify the parameters of influence of the performances, in particular the inductances of direct axes, Ld, and in quadrature, Lq. After machining three topologies of reluctant rotors associated with the stator of an asynchronous machine, we have experimentally identified these two intrinsic parameters (Ld, Lq) and then carried out various simulations in dynamic mode under MATLAB / Simulink environment.

Mots clés: synchronous reluctance machine ; parameters identification ; modeling; simulation ; MATLAB/Simulink.


Modeling Vapor-Liquid Equilibrium of CO2 in Aqueous MEA Using Hybrid Genetic Based Algorithm

جاب الله محمد العربي, 

Résumé: The extended UNIQUAC model, and the modified Clegg-Pitzer equation were separately applied to the vapor-liquid equilibrium of CO2 in aqueous monoethanolamine (MEA) solutions [15 and 30 mass% of MEA has been used over the temperature range of 313 - 393°K], the data results predicting such equilibrium were analyzed and compared. As Hybrid algorithm, the genetic algorithm (GA) and as deterministic model, the Nelder-Mead Simplex (NMS) method was used. In general, these models have been found suitable regarding the adjustments of experimental results of VLE measurement of this work as well as those in the cited literature. However, the UNIQUAC model gives more satisfactory results comparatively to Pitzer model.

Mots clés: Alkanolamine ; CO2 ; solubility ; MEA ; Optimzation ; Uniquac,


Enhancement of specific capacitance using hematite nanoparticles produced by green synthesis

الزين عبد الرؤوف, 

Résumé: Current research on iron oxide nanoparticles (Fe2O3-NPs) is extremely prolific because of their unique magnetic and electrical properties with a great application potential like in energy storage. The present paper describes green synthesis technique for the production of Fe2O3 NPs using aqueous olive leaf extract (OLE) as surfactant agent. Various characterization techniques were performed on those mesoporous Fe2O3 NPs such as Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The results demonstrate the spindle like shaped of Fe2O3 NPs with average particle size around 50-70 nm. The electrochemical performances of pristine activated carbon AC and the AC/Fe2O3 nanocomposite were compared in order to distinguish the added value of synthesized nanoparticles in energy storage. In comparison with pure AC electrode, AC/Fe2O3 nanocomposite electrodes exhibits an enhanced specific capacitance with values up to 87 F/ g.

Mots clés: Olive leaves extract ; AC/Fe2O3Nanoparticles ; Supercapacitors ; Nanostructured electrodes


Sustainable energy solutions for the agricultural world

بن حشاني الزهراء,  عزوي بوبكر,  عبد الصمد رشيد,  دومانجي كريم, 

Résumé: The majority of Algerian lands are arid and semi arid, containing an important number of agricultural farms that can be divided in two types; the first one is connected to grid and the second type is located in isolated zones. Both of these types of farms suffer of many problems due to lack of electrification. Firstly in the isolated sites, they use diesel engines which are limited principally to irrigation and house lighting for few hours a day because of high fuel costs and engine maintenance. Secondly for the farms connected to grid, they tend to suffer from the quality of electric energy due to very important voltage drops in the summer periods where the demand for electricity becomes high due to pumping water and air conditioning. This high energy consumption is reflected in the electricity bills which become a burden to the farmers. As Algeria is one of the countries that, has sunny days during all year, solar energy can contribute to solve these problems by feeding farms with electricity and giving them some advantages. To perform this study, we present the analysis of the farm’s loads, followed by the development of sizing systems where two farms (isolated and grid connected) are chosen for this study. Finally an implementation of solar stations is proposed.

Mots clés: Solar energy ; Solar radiation ; Photovoltaic systems ; Sizing model ; agricultural farms


NANOENCAPSULATION OF INSULINE BY ALGINATE/CHITOSANE MATRIX BY IONOTROPIC PRE-GELATION TECHNIQUE

Derbali Abir, 

Résumé: Insulin is the most effective hypoglycemic agent used to treat the diabetes. Oral administration of insulin is the most comfortable and least restrictive way. However, it encounters the low absorption of insulin by the digestive tract and its degradation by proteolytic enzymes. Several strategies have been developed to insulin protection against enzymatic hydrolysis in the gastro intestinal environment. They also aim to promote absorption and transport of insulin through the intestinal epit helium. In his context, we encapsulated insulin in alginate/chitosan based nanoparticles by the ionotropic gelation method. This technique comprises two steps, which are the cross link of alginate with calcium chloride followed by complexation with chitosan. The nanoparticles obtained are then coated with polyethylene glycol 400. Particle size and zeta potential were characterized, and encapsulated insulin amount was assessed.

Mots clés: Insulin ; Nanoparticles ; Alginate ; Chitosan ; Ionotropic pre-gelation


Formulation And Caracterisation Of Controlled Release Ketoprofen Microsponges

تواتي سهيلة,  كسيرة ياسر, 

Résumé: Microsponges are porous, polymeric microspheres drug delivery systems. They bestow a controlled release of drugs, reduce systemic side effects and enhance stability. The aim of the present work was to formulate microsponges loaded with Ketoprofen (KP) by the quasi emulsion solvent evaporation method using Ethyl cellulose (EC) as a polymer and the polyvinyl alcohol (PVA) as an emulsifying agent, to study the influence of drug: polymer ratio (Ra), emulsifier concentration (Emc) and stirring rate (Sr) on the production yield (PY), encapsulation efficiency (EE) using the design of experiment to identify the key factors and establish a relationship between the choosing response and those factors using analyze of variance (ANOVA) and to study the drug release and kinetics evaluation. Results revealed that the production yield and the entrapment efficiency are affected by polymer ratio (Ra), when the ratio change from 1:1 to 1:5 the production yield change from 40.42% to 81.97% and the encapsulation efficiency varies from 36.41% to 56.28% of Ketoprofen. The stirring rate and emulsifier concentration have no effect on production yield values. When we increase Sr and Emc from the min value to the max value, EE degrease from 48.37% to 43.72% and from 60.37% to 32.32% respectively. In vitro drug release studies were carried out up to 8 h in phosphate buffer (pH 6.8) media and the release data showed good correlation with the Higuchi model.

Mots clés: Microencapsulation ; Ketoprofen ; Ethyl Cellulose ; Microsponges ; Design of experiment


Evaluation of ultrasonic pretreatment on anaerobic digestion of citrus orange peel waste for methane production

Derbal Kerroum, 

Résumé: The study was performed in order to confirm and develop the possible use of orange peel waste in biogas production and to investigate ultrasonic pretreatment effect on enhancing biogas production. The inhibition by limonene present in the orange peel waste is the major challenge of biogas production from citrus waste, encountering this challenge was achieved by the removal of this substance using a steam distillation process. A batch anaerobic digestion experiment was performed at two thermal conditions thermophilic and mesophilic using a mixture of sludge and orange peel as a substrate in this study. In order to improve the solubilization of organic matter in the orange peels a mechanical pretreatment was applied: ultrasonification witch was carried out at a frequency of 37 kHz using an ultrasound cleaner for different exposure times 1 min, 5min, 10 min and 15 min which were investigated for the optimization. The obtained results of biogas production from the treated samples with the ultrasonic frequency showed a remarquable increase comparing with the untreated samples: 67% and 62% improvement after the ultrasonic pretreatment. Cumulative methane production of pretreated orange peel waste was the highest for the treatment times 1 and 10 minutes giving 970 mL.gTvs-1 and 671 mL.gTvs-1 for mesophilic and thermophilic phases respectively.

Mots clés: Anaerobic digestion ; biogas production ; limonene ; orange peel ; ultrasonification


Numerical simulation of CO 2 transport through hollow fiber membrane: Effect of chemical solvent

بلخيري نزيهة,  صاولي وسيل,  جرافي ختيمة, 

Résumé: In this study , a two-dimensional mathematical model is proposed to describe the transport of CO2 through HFMC with chemical reaction in the liquid phase .Numerical method of finite volume was used to solve the equation obtained for the three sections of the membrane contactor with the appropriate boundary conditions , The liquid solvents considered for this study include aqueous solution of Monoethanolamine (MEA) and water with a thin layer of the enzyme carbonic anhydrase (CA) .The modeling predictions indicated removal of CO2 using enzyme (CA) is more efficient than using MEA.

Mots clés: Carbone dioxide absorption, Membrane Gas Absorber, 2D Mathematical Modeling, Monoethanolamine , Carbone Anhydrase


Numerical simulation of a nanofluid flow in mixed convection inside a heated square cavity

Hamouche Adel, 

Résumé: In this work, we have numerically studied the two-dimensional and laminar flow of water, and nanofluid (Cu-water) in mixed convection inside a square cavity, where right and left walls are heated with a constant temperature and contain conductive fins. The lower and upper walls are adiabatic. The numerical resolution of the mathematical model was made by the finite volume method. The results obtained show that the Richardson number variations (Ri = 0.1, 0.5, 1, 5 and 10), the volume fraction (from 0.0 to 0.1), the aspect ratio as well as the angle of the cavity inclination have a considerable influence on the increase of the Nusselt number at the fins, and consequently on the improvement of the heat transfer inside the cavity.

Mots clés: mixed convection ; cavity ; fins ; cooling of electronic components ; nanofluids