Publications Internationales
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Item Glass foam composites based on tire's waste for microwave absorption application(Elsevier, 2020) Lamri, Y.; Benzerga, R.; Ayadi, A.; Gendre, L.L.; El-Assal, A.Waste glass and tire based glass-foams have been studied to produce a low-cost microwave absorbing material that could be used in building industry. These composites show, firstly, an heterogeneous structure induced by the degradation of the tires during the heat treatment, and secondly, low dielectric loss partially induced by their low densities. In order to avoid the heterogeneity of the samples, two different composites, using tire waste, have been tested. For the first composite, tires were coated with a refractory material, for the second, tires were pre-calcined before composite preparation. The use of calcined tires, which contain more than 99 wt.% of carbon, has led to homogenous composites with higher dielectric loss (tanδ = 0.33@10GHz). The absorption performance simulation of these composites shows encouraging results. A low reflection (close to −30 dB @ 11.90 GHz) and a large absorption bandwidth have been obtained for carbon (calcined tires) loaded foam composite with a thickness of 12 mm. © 2020 Elsevier B.VItem Elaboration and characterization of a cellular glass based cullet loaded with carbon fibers(Elsevier, 2015) Benhaoua, F.; Ayadi, A.; Stiti, N.; Lamri, Y.; Ratni, H.Item Elaboration and characterization of acellular glass based culletloaded with carbon fibers(Elsevier, 2015) Benhaoua, F.; Ayadi, A.; Stiti, N.; Lamri, Y.; Ratni, H.The foams glass whose porosity is very important, are counted among the new glass products that meet certain desired comfort needs in the particular building area (thermal and acoustic insulation). The objective of this study is to determine the influence of the carbon fibers addition influence on the porosity, the thermal insulation and dielectric loss of foams glass prepared by sintering at 800 °C, which opens the way to foam glass many possibilities for industrial to extend their opportunities that are very varied from thermal insulation to electromagnetic waves absorption. The carbon fibers addition used for this study is 1, 2, 3.5 and 5 wt% in relation to the foam glass load. Physico-chemical analysis techniques such as SEM-EDS, porosity, thermal insulation, differential thermal analysis, and dielectric tests have been used for the foams glass characterization. The obtained microstructure results clearly show that the 5 wt% carbon fibers addition increases the foam glass porosity which leads to low thermal conductivity (λ=0.0281 W/m°C) and increases its thermal insulating capacity. Furthermore the specific dielectric properties as real permittivity (ε'=2.7619) and high dielectric loss (tan δ=0.02969) favor the use of these glass filled foams with carbon fibers in the electromagnetic waves microwave absorption in the weakest working frequencies (mobile phones and Wi-Fi). © 2015 Elsevier B.V. All rights reservedItem Preparation and characterization of foam glass based waste(2011) Stiti, N.; Ayadi, A.; Lerabi, Y.; Benhaoua, F.; Benzerga, R.; Legendre, L.Item Study of vibratory behavior of interconnected porous PZT by impulse method(2010) Boumchedda, K.; Ayadi, A.; Aouaroun, T.; Fantozzi, G.Performances in ultrasonic active transducers of interconnected porous lead zirconate titanate (PZT) piezoelectric disks with a porosity ranging from 30 to 70%, and polarized along their axial axis, are investigated. The characterization method used is based on the measurement of the voltage, which appears between the two faces of the piezoelectric element when it is excited by a current impulse. The device used, allows the acquisition of axial and radial vibrations of the transducer, and from these data, electromechanical and acoustic parameters are deduced. One observes that interconnected porosity causes the disappearance of the radial vibrations, and for large porosities the disk vibrates exclusively according to the axial mode. kt is increased, the acoustic impedance is reduced, and the axial propagation velocity reaches ∼2500 m s−1 for 30% of porosity. These results show that interconnected porous PZT are suitable for making ultrasonic active transducer, such as biomedical imaging devicesItem Elaboration and characterization of porous granules based on waste glass(2011) Ayadi, A.; Stit, N.; Boumchedda, K.; Rennai, H.; Lerari, Y.The evolutions of the world today and the population increase have resulted in pollution and human wastes, which contaminate the environment and adversely affect the human's quality of life. All forms of food and drink packages, made of paper, plastic foam, aluminum and glass, are designed for the consumers' convenience. After being used, these packages are discarded as garbage and have today become a social problem. It is in this context that our work for obtaining a building material (foam glass granules) that is much lighter is registered with the properties of heat insulation and acoustic improved based on cullet in order to recycle it and for improving the present laws about the waste products in closed circuit (finished products → waste products → finished products). Investigations have shown that grinding waste glass to particle size less than 0.1mm and adding 1% of Ca CO3 content provide the production of material with the following properties: particle density of 0.5 g/cm3, strength of 17.50 MPa and water adsorption of 95%, with the temperature for foaming ranges determined at 850 °C. The microstructures are homogenous, with pore sizes of up to 2 mm. The foamglass is counted among the newglass products meeting certain requirements on comfort, in particular in the building industry (thermal and acoustic insulation). The product obtained presents excellent thermal (λ=0,031 W/m°C) and acoustic (R=15 dB) propertiesItem Elaboration and characterization of foam glass based waste Asian(2011) Ayadi, A.; Stiti, N.; Benhaoua, F.; Lerari, Y.; Benzerg, R.; Legendre, L.The porous glass ‘foam glass’ is considered as the new glass products fulfill certain requirements in the building industry in particular (thermal and acoustic insulation). The production of foam glass based waste glass plays an important role in environmental protection and also gains in energy. As part of present work, we seek to improve the properties of glass to obtain a building material lighter with excellent insulation properties. The properties of foam glass depend on the porosity and morphology. The present work devoted to analyze the microstructure of the glass produced by scanning electron microscopy and optical microscopy to be more precise on the size and shape of pores constitute this materialItem Effect of the AL2O3 and BaO addition on the thermal and physical properties of ternary glass system (B2O3- BaO-AL2O3)(DAVID PUBLISHING, 2013) Aboutaleb, Djamila; Safi, Brahim; Ayadi, A.; Iratni, A.In borate glasses, the main structural units are the [BO3] triangles and [BO4] tetradral which form different superstructural units like; boroxol rings, metaborate rings and chains, pentaborate, diborate, triborate and pyroborate. In this work, the Barium aluminoborate glasses were prepared. Some of properties were investigated by measure like density and chemical durability and the other by calculs. The dilatometric curves were determined and they revealed that the temperature of transition (Tg) and softening (Ts) and the dilatation coefficient increase by addition of Al2O3 and BaO content