0000000000266522

AUTHOR

Mohamed El Maaoui

showing 3 related works from this author

Natural fluorapatite as a raw material for Portland clinker

2018

Abstract The present work focuses on the mineralogy and the reactivity of clinkers made from the integration of natural fluorapatite in the raw meals with percentages ranging from 0 up to15%. The samples were characterized by infrared spectrometry, X-ray diffraction and microscopy techniques. The distribution of phosphorous and fluorine into clinkers minerals was determined by MEB/EDS mapping. The mineralogical composition was determined by XRD/Rietveld and the samples reactivity followed by isothermal microcalorimetry. It has been found that fluorine stabilizes C3S and β-C2S which still are found with high levels of P2O5. Cements obtained from up to 8% natural fluorapatite incorporation st…

CementIsothermal microcalorimetryMaterials scienceMetallurgyFluorapatite0211 other engineering and technologieschemistry.chemical_elementInfrared spectroscopy02 engineering and technologyBuilding and ConstructionRaw material021001 nanoscience & nanotechnologyClinker (cement)chemistry021105 building & constructionFluorineGeneral Materials ScienceReactivity (chemistry)0210 nano-technologyCement and Concrete Research
researchProduct

Dielectric relaxation phenomenon and conductivity in lead-free ceramics

2018

Abstract Relaxation phenomena and electric conductivity of (1-x) KNbO3-xK0.5Bi0.5TiO3 system where x = 0, 0.025, 0.05, 0.075, 0.1, 0.2, 0.3 have been studied at high temperature. A relaxation behavior was observed in temperature range 400 K ≤ T ≤ 550 K for orthorhombic solid solutions at room temperature. The activation energy (Ea) of this phenomenon was range from 0.68 eV for x = 0–0.489 eV for x = 0.075 with τ0 = 10−13 s. The relaxation was attributed to hopping of oxygen vacancies for solid solutions x ≤ 0.075. Substitution by K0.5Bi0.5TiO3 does not affect the electrical conductivity of KNbO3 too much, while the mobility of species such as oxygen vacancies and oxygen ions allow the incre…

Materials scienceCondensed matter physicschemistry.chemical_element02 engineering and technologyActivation energyDielectricConductivityAtmospheric temperature range010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesOxygen0104 chemical sciencesElectronic Optical and Magnetic MaterialschemistryElectrical resistivity and conductivityRelaxation (physics)Electrical and Electronic Engineering0210 nano-technologySolid solutionPhysica B: Condensed Matter
researchProduct

Effect of mechanical stirring and temperature on dynamic hydrothermal synthesis of titanate nanotubes

2017

Abstract In the late century, it has been clearly demonstrated that titanate nanotubes (TNTs) are attractive nanomaterials with various potential applications due to their interesting properties. In this work, an essential reaction parameter, rarely considered in the literature, has been studied: stirring during hydrothermal synthesis. For this purpose, an intermittent mechanical stirring, ranging from 0 to 20 min/h, has been applied during the TNTs synthesis using a new dynamic hydrothermal reactor. It was proved that a long stirring cycle (more than 10 min/h) at 150 °C and an overall reaction time of 16 h promotes nanoribbons synthesis instead of nanotubes. In this context, a detailed mor…

Work (thermodynamics)Materials scienceMechanical EngineeringMetals and AlloysContext (language use)Nanotechnology02 engineering and technology010402 general chemistry021001 nanoscience & nanotechnology01 natural sciencesHydrothermal circulation0104 chemical sciencesCharacterization (materials science)NanomaterialsChemical kineticsChemical engineeringMechanics of MaterialsMaterials ChemistryHydrothermal synthesis0210 nano-technologyDissolutionJournal of Alloys and Compounds
researchProduct