Institute Preparatoire Aux Etudes dIngenieurs dEl Manar

Tunis, Tunisia

Institute Preparatoire Aux Etudes dIngenieurs dEl Manar

Tunis, Tunisia
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Marzouki R.,Laboratoire Of Materiaux Et Cristallochimie | Guesmi A.,Laboratoire Of Materiaux Et Cristallochimie | Guesmi A.,Institute preparatoire Aux etudes Dingenieurs DEl Manar | Zid M.F.,Laboratoire Of Materiaux Et Cristallochimie | Driss A.,Laboratoire Of Materiaux Et Cristallochimie
Annales de Chimie: Science des Materiaux | Year: 2013

The structural study of the compound Na4CO5,63Alo,91(AsO4)6 [1], the first explored in the system, shows that the material forms a three dimensional framework with hexagonal tunnels running along the [100] and communicate along [010] direction with tetragonal windows where Na+cations are located. Complementary infrared (IR) and complex impedance (CI) spectroscopies studies were carried out. Analysis by scanner electronic microscope (S.E.M) was done for the state. The ionic conductivity measurements were performed on pellets of polycrystalline powders. The monovalent cations conduction pathways in the crystal bulks are simulated by means of the bond valence model (BVS). © Lavoisier, Paris Physico-chimie d'un monoarséniate mixte.


Nait-Abdelaziz M.,University of Lille Nord de France | Nait-Abdelaziz M.,Lille Laboratory of Mechanics | Zairi F.,University of Lille Nord de France | Zairi F.,Lille Laboratory of Mechanics | And 4 more authors.
Mechanics of Materials | Year: 2012

Using the fracture mechanics framework, a fracture criterion based upon the intrinsic defect concept was developed to predict the failure of rubber parts under biaxial monotonic loading. This fracture criterion requires as input data the fracture toughness of the material in terms of critical value of the J integral, the constitutive law of the material and the breaking stretch of a smooth specimen under uniaxial tension. To develop this criterion a generalized expression of the J integral under biaxial loading is proposed on the basis of finite element calculations on a RVE containing a small circular defect. The estimated failure elongations were found in very nice agreement with experimental data on two kinds of rubber materials. Moreover, we have also shown that this criterion could be extended to the failure analysis of thermoplastic polymers. © 2012 Elsevier Ltd. All rights reserved.


Guesmi A.,Université Ibn Tofail | Guesmi A.,Institute Preparatoire aux Etudes dIngenieurs dEl Manar | Driss A.,Université Ibn Tofail
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2012

The two title compounds, potassium diaqua-cobalt(II) borodiphosphate 0.48-hydrate and potassium-calcium(0.172/0.418) diaqua-cobalt(II) borodiphosphate monohydrate, were synthesized hydro-thermally. They are new members of the borophos-phate family characterized by ∞[BP 2O8]3- helices running along [001] and constructed of boron (Wyckoff position 6b, twofold axis) and phospho-rus tetra-hedra. The [CoBP2O8]- anionic frameworks in the two materials are structurally similar and result from a connection in the ab plane between the CoO4(H2O)2 coordination octa-hedra (6b position) and the helical ribbons. Nevertheless, the two structures differ in the disorder schemes of the K,Ca and H2O species. The alkali cations in the structure of the pure potassium compound are disordered over three independent positions, one of them located on a 6b site. Its framework is characterized by double occupation of the tunnels by water mol-ecules located on twofold rotation axes (6b) and a fraction of alkali cations; its cell parameters, compared with those for the mixed K,Ca compound, show abnormal changes, presumably due to the disorder. For the K,Ca compound, the K and Ca cations are on twofold axes (6b) and the channels are occupied only by disordered solvent water mol-ecules. This shows that it is possible, due to the flexibility of the helices, to replace the alkali and alkaline earth cations while retaining the crystal framework. © 2012 International Union of Crystallography.


Ben Smida Y.,Université Ibn Tofail | Guesmi A.,Université Ibn Tofail | Guesmi A.,Institute Preparatoire Aux Etudes dIngenieurs dEl Manar | Driss A.,Université Ibn Tofail
Acta Crystallographica Section E: Structure Reports Online | Year: 2013

The title compound, lithium dicobalt(II) triarsenate, LiCo 2As3O10, was synthesized by a solid-state reaction. The As atoms and four out of seven O atoms lie on special positions, all with site symmetry m. The Li atoms are disordered over two independent special (site symmetry -1) and general positions with occupancies of 0.54 (7) and 0.23 (4), respectively. The structure model is supported by bond-valence-sum (BVS) and charge-distribution (CHARDI) methods. The structure can be described as a three-dimensional framework constructed from bi-octahedral Co 2O10 dimers edge-connected to As3O10 groups. It delimits two sets of tunnels, running parallel to the a and b axes, the latter being the larger. The Li+ ions are located within the intersections of the tunnels. The possible motion of the alkali cations has been investigated by means of the BVS model. This simulation shows that the Li + motion appears to be easier mainly along the b-axis direction and that this material may possess interesting conduction properties. © Ben Smida et al. 2013.


Marzouki R.,Université Ibn Tofail | Guesmi A.,Université Ibn Tofail | Guesmi A.,Institute Preparatoire Aux Etudes dIngenieurs dEl Manar | Driss A.,Université Ibn Tofail
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2010

The title compound, tetrasodium cobalt aluminium hexaarsen-ate, Na 4Co7-x Al2/3x (AsO4)6 (x = 1.37), is isostructural with K4Ni7(AsO4) 6; however, in its crystal structure, some of the Co2+ ions are substituted by Al3+ in a fully occupied octa-hedral site (site symmetry 2/m) and a partially occupied tetra-hedral site (site symmetry 2). A third octa-hedral site is fully occupied by Co2+ ions only. One of the two independent tetra-hedral As atoms and two of its attached O atoms reside on a mirror plane, as do two of the three independent Na+ cations, all of which are present at half-occupancy. The proposed structural model based on a careful investigation of the crystal data is supported by charge-distribution (CHARDI) analysis and bond-valence-sum (BVS) calculations. The correlation between the X-ray refinement and the validation results is discussed. © 2010 International Union of Crystallography.


Arfaoui Y.,Université Ibn Tofail | Kouass S.,Université Ibn Tofail | Salah N.,Université Ibn Tofail | Ben Akacha A.,Université Ibn Tofail | And 2 more authors.
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2010

In the title compound, C11H21N2O 5P, one of the two carbazate N atoms is involved in the C=N double bond and the H atom of the second N atom is engaged in an intra-molecular hydrogen bond with an O atom from the dimethyl-phospho-rin-2-yl group, which is in an uncommon cis position with respect to the carbamate group. The cohesion of the crystal structure is also reinforced by weak inter-molecular hydrogen bonds. Density functional theory (DFT) calculations at the B3LYP/6-311++g(2d,2p) level revealed the lowest energy structure to have a Z configuration at the C=N bond, which is consistent with the configuration found in the X-ray crystal structure, as well as a less stable E counterpart which lies 2.0 kcal mol -1 higher in potential energy. Correlations between the experimental and computational studies are discussed. © 2010 International Union of Crystallography.


Ali Tabarki M.,Tunis el Manar University | Ben Smida Y.,Tunis el Manar University | Guesmi A.,Tunis el Manar University | Guesmi A.,Institute Preparatoire aux Etudes dIngenieurs dEl Manar | Besbes R.,Tunis el Manar University
Acta Crystallographica Section E: Crystallographic Communications | Year: 2015

The title compound, C20H72ClN2O3, was obtained via an original synthesis method. The central heterocyclic ring adopts a shallow envelope conformation, with the N atom bearing the cyclopentane ring as the flap [deviation from the other atoms = 0.442 (2) Å]. The cyclopentane ring adopts a twisted conformation about one of the CN-C bonds: the exocyclic C-N bond adopts an equatorial orientation. The dihedral angles between the central ring (all atoms) and the pendant five- and six-membered rings are 10.3 (2) and 87.76 (14)°, respectively. In the crystal, C-H⋯O interactions link the molecules into [011] chains. A weak C-H⋯Cl interaction links the chains into (100) sheets. A mechanism for the cyclization reaction is proposed.


Guesmi A.,Université Ibn Tofail | Guesmi A.,Institute Preparatoire aux Etudes dIngenieurs dEl Manar | Driss A.,Université Ibn Tofail
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title compound, trisodium dicobalt arsenate diarsenate, Na 3Co2AsO4As2O7, the two Co atoms, one of the two As and three of the seven O atoms lie on special positions, with site symmetries 2 and m for the Co, m for the As, and 2 and twice m for the O atoms. The two Na atoms are disordered over two general and special positions [occupancies 0.72 (3):0.28 (3) and 0.940 (6):0.060 (6), respectively]. The main structural feature is the association of the CoO 6 octahedra in the ab plane, forming Co4O20 units, which are corner- and edge-connected via AsO4 and As 2O7 arsenate groups, giving rise to a complex polyhedral connectivity with small tunnels, such as those running along the b- and c-axis directions, in which the Na+ ions reside. The structural model is validated by both bond-valence-sum and charge-distribution methods, and the distortion of the coordination polyhedra is analyzed by means of the effective coordination number. © 2012 International Union of Crystallography.

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