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432 results on '"Fatmi, M."'

20. Effect of temperature and glass content on crystalline phases in porcelain sintered with recovered automotive glass

Author

A. Djemli, M.A. Ghebouli, K. Bouferrache, Y. Slimani, Mohamed A. Habila, Fatmi M, T. Chihi, B. Ghebouli, and Mika Sillanpää

Subjects
Feldspars, Crystalline phases, Porcelain, Mullite, Science (General), Q1-390, Social sciences (General), H1-99
Abstract

In the pursuit of sustainable porcelain production, this research examines the potential of using recovered automotive glass as a substitute for traditional feldspar, specifically feldspar imported from Spain. Porcelain samples were sintered at different temperatures and with varied proportions of automotive glass. The crystalline phases formed post-sintering were determined through X-ray diffraction and quantified by dissolving the porcelain in concentrated hydrofluoric acid. Results revealed that the inclusion of automotive glass, owing to its dissolved oxide content, accelerated the porcelain melting process and led to an increase in the vitreous phase. Notably, anorthite phases became dominant and mullite formation was evident at 1100 °C, stabilizing in samples G00 and G10, and then increasing at 1200 °C due to the emergence of secondary mullite. This secondary mullite forms from the residual silica after the primary mullite formation and the aluminium in the feldspars, which is about 17 %. For samples G20 and G30, only primary mullite was observed due to the decreased aluminium content resultant from feldspar replacement by glass. These findings underscore the viability of automotive glass in porcelain production, providing a sustainable and effective alternative to feldspar.

Published
2023
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31. Effect of functional on structural, elastic stability, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X = Lu, Y) spinels.

Author

BOUFERRACHE, K, GHEBOULI, M A, SLIMANI, Y, GHEBOULI, B, FATMI, M, CHIHI, T, HABILA, MOHAMED A, ALOTAIBI, NOUF H, and SILLANPAA, MIKA

Abstract

Effect of functional on structural, elastic, optoelectronic and thermoelectric characteristics of semiconducting MgX2Se4 (X = Lu, Y) spinels has been realized by WIEN2k code. The lattice constant of MgY2Se4 is slightly greater than that of MgLu2Se4, and these quantities are slightly deviated from the experimental values, where the error does not exceed 1.3%. The cohesive energy proves that both spinels are chemically stable in the normal case, and this stability is more pronounced in MgLu2Y4. The large ionic radius of Lu compared to Y explains the high bulk modulus of MgY2Se4 as well as its hardness. The spinels under study have Г → Г direct band gap located between 1.178 and 1.4 eV for all the functionals, proving their semiconductor nature. Se-s, Y-d, Lu-d states in MgY2Se4 and MgLu2Se4 dominate the upper valence band, while the first conduction band located between Fermi level and 1.5 eV is empty. There is a strong coupling between Se-p–Lu-p sites for MgLu2Se4 and Se-p–Y-p states in MgY2Se4, which reflects their hybridization. The high absorption in the ultraviolet range, the band gap between 1 and 2.4 eV and the refractive index in the range of 2.29–2.61 favour these spinels as absorbers in solar cells. Peaks of all the optical quantities studied relating to the mBJ–GGA functional are shifted to the right compared with GGA and GGA+SO approximations. The thermoelectric parameters were investigated as a function of photon energy and temperature using GGA+SO functional. [ABSTRACT FROM AUTHOR]

Published
2024
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32. Prediction Study of Thermoelectric Properties of TiO2 Nanoparticles and Effect on PVA/SiO 2 Hybrid Films Synthesized by sol-gel Method

Author

Gueridi, B., primary, Slimani, Y., additional, Bouferrache, K., additional, Ghebouli, M. A., additional, Rouabah, F., additional, Chihi, T., additional, Fatmi, M., additional, Ghebouli, B., additional, Djemli, A., additional, Alotaibi, Nouf H., additional, Mohammad, Saikh, additional, and Benali, A., additional

Published
2024
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39. Prediction study of structural, thermal, and optical characterization of Co0.6Zn0.4Fe2O4cubic spinel synthesized via sol–gel method for energy storage

Author

Messaoudi, A., Omri, Aref, Benali, A., Ghebouli, M. A., Djemli, A., Fatmi, M., Habila, A., Alothman, Asma A., Hamdaoui, N., Ajjel, R., Costa, B. F. O., Graca, M. F. P., and Khirouni, K.

Abstract

In this comprehensive study, we synthesized Co0.6Zn0.4Fe2O4cubic spinel via the sol–gel method and characterized its structural, thermal, and optical properties. X-ray diffraction (XRD) verified the crystallization within the cubic Fd-3 m space group, and a detailed analysis determined a crystallite size ranging from 47 to 58 nm. Notably, the calculated crystallite size of 49.4 nm revealed inherent limitations in Scherer’s formula, which does not account for intrinsic strain effects from crystal defects, grain boundaries, and stacking. Optical investigations, utilizing UV–Vis absorption spectroscopy, unveiled a direct optical band gap of 1.26 eV, suggesting semiconductor behavior. The material’s thermal conductivity was found to be highly temperature sensitive, reaching its maximum value for both spin orientations at 900 K, with a quantified value of ke/τ = 4 × 1014 W/(mKs). This thermal behavior, along with the observed disorder (Eu value of 1.41 eV) and higher Urbach energy, offers valuable insights into the material’s response under varying temperature conditions, essential for applications in diverse technological domains.

Published
2024
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40. Sustainable porcelain ceramics production using local raw materials and recycled automotive glass.

Author

Djemli, A., Belhouchet, H., Faci, A., Ghebouli, M. A., Bouferrache, K., Slimani, Y., Chihi, T., Ghebouli, B., Fatmi, M., Algethami, Norah, Mouhammad, Saif A., and Alomairy, Sultan

Subjects
AUTOMOTIVE materials, RAW materials, GLASS recycling, PORCELAIN, CERAMICS, GLASS-ceramics
Abstract

The main objective of this research is the explanation of the replacement of feldspar limestone imported from Spain with recycled automotive glass, in order to reduce waste and promote environmental sustainability. Details and efforts of making porcelain ceramics from local raw materials such as quartz, kaolin and glass are also given. Replacing the feldspar with reclaimed automotive glass shows the effect of the Na2O and CaO solvents contained in the glass on the sintering and crystallization of the studied porcelain. The results showed that the added glass contributes to the reduction of the density and the acceleration of the sintering process, by occupying the sites of the open spaces, observed in the samples not containing feldspars. By reaching a nonporous ratio at a temperature of 1000∘C, the melting of the material is accelerated due to the dissolved oxides it contains, in addition to the linear shrinkage rate in samples that contain a lot of glass reaching the normal level of porcelain (about 12%) at low temperature compared to ordinary porcelain. [ABSTRACT FROM AUTHOR]

Published
2024
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49. T-Analyst: a program for efficient analysis of protein conformational changes by torsion angles

Author

Ai, Rizi, Qaiser Fatmi, M., and Chang, Chia-en A.

Subjects
Chemistry, Computer Applications in Chemistry, Animal Anatomy / Morphology / Histology, Physical Chemistry, Molecular dynamics, Entropy, Allosteric, Simulation, Drug screening, Docking, HIV protease, AMBER
Abstract

T-Analyst is a user-friendly computer program for analyzing trajectories from molecular modeling. Instead of using Cartesian coordinates for protein conformational analysis, T-Analyst is based on internal bond-angle-torsion coordinates in which internal torsion angle movements, such as side-chain rotations, can be easily detected. The program computes entropy and automatically detects and corrects angle periodicity to produce accurate rotameric states of dihedrals. It also clusters multiple conformations and detects dihedral rotations that contribute hinge-like motions. Correlated motions between selected dihedrals can also be observed from the correlation map. T-Analyst focuses on showing changes in protein flexibility between different states and selecting representative protein conformations for molecular docking studies. The program is provided with instructions and full source code in Perl.

Published
2010

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