2 résultat(s) recherche sur le tag 'glass'    

Caractérisations physico-chimiques et cinétique de bioactivité des biomateriaux / Fatima-Zohra Mezahi  

Public ISBD Titre : Caractérisations physico-chimiques et cinétique de bioactivité des biomateriaux : hydroxyapatite & verre bioactif 54S4 élaboré par fusion et par voie sol-gel Type de document : texte imprimé Auteurs : Fatima-Zohra Mezahi ; Université Mentouri, Editeur scientifique ; A. Harabi, Directeur de thèse Année de publication : 2009 Importance : 177 f. Note générale : 01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD Langues : Français (fre) Tags : Verre  Hydroxyapatite  Voie fusion  Procédé sol-gel  Bioactivité  Solution physiologique  Glass  Melting process  Sol  gel process  Bioactivity  ?????????????????  ???????  ????? ????????  ????-????  ?????? ??????  ?????? ????????? Index. décimale : 530 Physique Résumé : This work has been devoted to study the bioactive materials: - The natural and synthetic hydroxyapatite. - Quaternary glass 52S4: 52% SiO2- 30% CaO -14% Na2O- 4% P2O5 (wt%). Among the main techniques used for both physical and chemical characterizations of these biomaterials are: the Induced Coupled Plasma (ICP-OES), X- Ray Diffraction (XRD), Scanning Electron Microscopy (SEM-EDS), Infra-Red spectroscopy (IR) and Nuclear Magnetic Resonance (NMR). The obtained results show that the hydroxyapatite bioactivity is controlled by several factors such as the density, trace elements and the second phase formation. In addition, mechanical properties optimization by adding inert oxides (ZrO2, TiO2 and Al2O3) is not always accompanied by HA bioactivity improvement. It has been found that the presence of certain foreign oxides in the HA matrix inhibits “bone-like apatite” formation at the immerged HA surface in a Simulated Body Fluid (SBF). As far as glasses are concerned, two synthesis routes have been used: the melting and sol-gel processes, which allow to obtain a porous glass with a large specific area. The immersion of these glasses in SBF and Phosphor Buffered Solution (PBS) has allowed to conclude that: - the glasses synthesised by melting and sol-gel processes are bioactive, - the bioactivity kinetic is very sensitive to several factors, such as porosity, the dissolution kinetics of glasses and the ion concentrations of the immersion solution. These work results confirm that glasses are more reactive than hydroxyapatite by carbonated apatite formation on its surface, in a very short time. Diplôme : Doctorat en sciences En ligne : ../theses/physique/MEZ5504.pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=3430 Caractérisations physico-chimiques et cinétique de bioactivité des biomateriaux : hydroxyapatite & verre bioactif 54S4 élaboré par fusion et par voie sol-gel [texte imprimé] / Fatima-Zohra Mezahi ; Université Mentouri, Editeur scientifique ; A. Harabi, Directeur de thèse . - 2009 . - 177 f. 01 Disponible à la salle de recherche 02 Disponibles au magazin de la B.U.C. 01 CD Langues : Français (fre) Tags : Verre  Hydroxyapatite  Voie fusion  Procédé sol-gel  Bioactivité  Solution physiologique  Glass  Melting process  Sol  gel process  Bioactivity  ?????????????????  ???????  ????? ????????  ????-????  ?????? ??????  ?????? ????????? Index. décimale : 530 Physique Résumé : This work has been devoted to study the bioactive materials: - The natural and synthetic hydroxyapatite. - Quaternary glass 52S4: 52% SiO2- 30% CaO -14% Na2O- 4% P2O5 (wt%). Among the main techniques used for both physical and chemical characterizations of these biomaterials are: the Induced Coupled Plasma (ICP-OES), X- Ray Diffraction (XRD), Scanning Electron Microscopy (SEM-EDS), Infra-Red spectroscopy (IR) and Nuclear Magnetic Resonance (NMR). The obtained results show that the hydroxyapatite bioactivity is controlled by several factors such as the density, trace elements and the second phase formation. In addition, mechanical properties optimization by adding inert oxides (ZrO2, TiO2 and Al2O3) is not always accompanied by HA bioactivity improvement. It has been found that the presence of certain foreign oxides in the HA matrix inhibits “bone-like apatite” formation at the immerged HA surface in a Simulated Body Fluid (SBF). As far as glasses are concerned, two synthesis routes have been used: the melting and sol-gel processes, which allow to obtain a porous glass with a large specific area. The immersion of these glasses in SBF and Phosphor Buffered Solution (PBS) has allowed to conclude that: - the glasses synthesised by melting and sol-gel processes are bioactive, - the bioactivity kinetic is very sensitive to several factors, such as porosity, the dissolution kinetics of glasses and the ion concentrations of the immersion solution. These work results confirm that glasses are more reactive than hydroxyapatite by carbonated apatite formation on its surface, in a very short time. Diplôme : Doctorat en sciences En ligne : ../theses/physique/MEZ5504.pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=3430

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Modelisation et optimisation des capteurs solaires hybrides. / Amel Ghellab  

Public ISBD Titre : Modelisation et optimisation des capteurs solaires hybrides. Type de document : texte imprimé Auteurs : Amel Ghellab, Auteur ; Abdennacer Kabi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 120 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles. Langues : Français (fre) Tags : Cellule PV  capteur solaire  verre  PMMA  air  eau  nanofluides  modélisation  simulation  performances  PV cell  solar collector  glass  water  nanofluids  modeling  ??????? ???????????  ????? ?????? ???????  ??????  ?????  ?????? ??????  ???????  ???????? Index. décimale : 626 Génie Climatique Résumé : The growing in demand of energy risks exhausting totally different conventional fields, so in order to mitigate many states turn to deal with it and in the same time they wanted to maximize performance with less costs. Thus we have developed a study highlighting the use of solar by introducing the hybrid photovoltaic / thermal collector consisting of a PV module under which a heat exchanger is provided to ensure the cooling of the cells. The energy produced will be used to generate electricity and heat. At this stage we have studied the feasibility by taking two elements that are plastics as cover and nanofluids as cooling fluid. Regarding plastics, these have proved to be the most widely used materials for the manufacture of various components, in particular those of solar heating ... etc. As for nanofluids, it is a new technology that has revolutionized all those that have preceded it because they have high thermo physical properties. At this stage, the study proposes the simulation of two different systems in forced convection inside the fluid channel, both for plastics and for nanofluids, the two systems proposed were based on the development of an energy balance between the different nodes of the system. Hence the equations will be discretized and then introduced into a program written in Matlab for the purpose of calculating the unknowns and also being able to validate our results. The results show that the use of PMMA is beneficial for transmitting more radiation compared to the glass and as for the nanofluids, the extraction of the heat under the panel proved to be better compared to the conventional fluids. Diplôme : Doctorat en sciences En ligne : ../theses/gclim/GHE7207.pdf Format de la ressource électronique : pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10756 Modelisation et optimisation des capteurs solaires hybrides. [texte imprimé] / Amel Ghellab, Auteur ; Abdennacer Kabi, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 120 f. ; 30 cm. 2 copies imprimées disponibles. Langues : Français (fre) Tags : Cellule PV  capteur solaire  verre  PMMA  air  eau  nanofluides  modélisation  simulation  performances  PV cell  solar collector  glass  water  nanofluids  modeling  ??????? ???????????  ????? ?????? ???????  ??????  ?????  ?????? ??????  ???????  ???????? Index. décimale : 626 Génie Climatique Résumé : The growing in demand of energy risks exhausting totally different conventional fields, so in order to mitigate many states turn to deal with it and in the same time they wanted to maximize performance with less costs. Thus we have developed a study highlighting the use of solar by introducing the hybrid photovoltaic / thermal collector consisting of a PV module under which a heat exchanger is provided to ensure the cooling of the cells. The energy produced will be used to generate electricity and heat. At this stage we have studied the feasibility by taking two elements that are plastics as cover and nanofluids as cooling fluid. Regarding plastics, these have proved to be the most widely used materials for the manufacture of various components, in particular those of solar heating ... etc. As for nanofluids, it is a new technology that has revolutionized all those that have preceded it because they have high thermo physical properties. At this stage, the study proposes the simulation of two different systems in forced convection inside the fluid channel, both for plastics and for nanofluids, the two systems proposed were based on the development of an energy balance between the different nodes of the system. Hence the equations will be discretized and then introduced into a program written in Matlab for the purpose of calculating the unknowns and also being able to validate our results. The results show that the use of PMMA is beneficial for transmitting more radiation compared to the glass and as for the nanofluids, the extraction of the heat under the panel proved to be better compared to the conventional fluids. Diplôme : Doctorat en sciences En ligne : ../theses/gclim/GHE7207.pdf Format de la ressource électronique : pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10756

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