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Jamel Bouaziz

Ecole Nationale d'Ingénieurs de Sfax (ENIS), Génie Des Matériaux, Faculty Member

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University of California, Santa Barbara

József Böröcz

Rutgers, The State University of New Jersey

Antioch University

University of British Columbia

Lancaster University

University of Exeter

Marianna Sigala

University of South Australia

University of Tehran

Kozminski University

Juraj Marušiak

Slovak Academy of Sciences

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Papers by Jamel Bouaziz

Nanocomposite and nanostructures coatings for LED lighting and photocatalytic applications

International audienc

How Artificial Intelligence Can Improve Our Understanding of the Genes Associated with Endometriosis: Natural Language Processing of the PubMed Database

BioMed Research International, 2018

Endometriosis is a disease characterized by the development of endometrial tissue outside the ute... more Endometriosis is a disease characterized by the development of endometrial tissue outside the uterus, but its cause remains largely unknown. Numerous genes have been studied and proposed to help explain its pathogenesis. However, the large number of these candidate genes has made functional validation through experimental methodologies nearly impossible. Computational methods could provide a useful alternative for prioritizing those most likely to be susceptibility genes. Using artificial intelligence applied to text mining, this study analyzed the genes involved in the pathogenesis, development, and progression of endometriosis. The data extraction by text mining of the endometriosis-related genes in the PubMed database was based on natural language processing, and the data were filtered to remove false positives. Using data from the text mining and gene network information as input for the web-based tool, 15,207 endometriosis-related genes were ranked according to their score in t...

Performance Enhancement of Kaolin/Chitosan Composite-Based Membranes by Cross-Linking with Sodium Tripolyphosphate: Preparation and Characterization

Membranes

A new family of environmentally friendly and low-cost membranes based on readily available minera... more A new family of environmentally friendly and low-cost membranes based on readily available mineral and polymeric materials has been developed from cast suspensions of kaolin and chitosan using aqueous phase separation and polyethylene glycol as a pore-forming agent. The as-fabricated membranes were further cross-linked with sodium tripolyphosphate (STPP) in order to strengthen the properties of the obtained samples. The functional groups determined by FTIR and EDX confirmed that the reaction occurred. A detailed study of the effects of cross-linking time on the physicochemical, surface and permeation properties showed that a 30-minute reaction enabled the composite membrane to be stable in acidic media (up to pH 2) and increased the mechanical strength twofold compared to the non-cross-linked membrane. A similar morphology to that generally observed in polymeric membranes was obtained, with a sponge-like surface overlaying a finger-like through structure. The top layer and cross-sec...

Characterization of tricalcium phosphate-fluorapatite ceramics composites by ultrasonic testing

Faraday Effect in Doped Aerogels

Le Journal de Physique Colloques, 1989

prepares par l a m6thode s o l-g e l &I p a r t i r des n i t r a t e s de dysprosium ou d'erbium... more prepares par l a m6thode s o l-g e l &I p a r t i r des n i t r a t e s de dysprosium ou d'erbium e t de tBtram6thoxysilane (TMOS). Des aerogels avec des c o n c e n t r a t i o n s 4lev6es en 1 anthani des (14% mol a i r e) o n t 6 t 6 obtenus. Les constantes de Verdet de ces aerogels o n t B t 6 determinees.

Valorization of Marine Sediments in a Proteinic Biopolymer: Modeling of the Mechanical Behavior

J Polym Environ, 2014

Biocomposites, which consist of renewable resources like proteins, have been extensively investig... more Biocomposites, which consist of renewable resources like proteins, have been extensively investigated. However, studies on the combination of marine sediments and proteinic biopolymer have not been conducted yet. In this work, marine sediments were added to the matrix in proportions ranging from 0 to 20 %. The mechanical properties in terms of tensile, flexural and compressive strength tests were investigated. Thermogravimetric analysis were also used to assess the thermal stability of the produced composites. The hemoglobin marine sediments (HESM) may be dedicated to ground coating or to wall covering, it is then necessary to perform a preliminary structure analysis. A multi-phase mechanical model able to reproduce the compressive behavior of the HESM is developed in order to simulate the HESM coating at different marine sediments ratios and different strain rates. The incorporation of sediments increases the stiffness of the material and improves the compressive properties of the composite.

Effect of the surface chemistry on the stability and mechanical properties of the Zirconia-Hydroxyapatite bioceramic

Surfaces and Interfaces, 2021

Abstract Hydroxyapatite/zirconia powders were produced by soft chemistry and characterized by sev... more Abstract Hydroxyapatite/zirconia powders were produced by soft chemistry and characterized by several techniques. The effects of the sintering temperature on the densification, microstructure and mechanical properties of the bioceramics were studied. The HAP-10%ZrO2 bioceramic was chosen for its specific advantages. Microstructural and textural characterization reveal disappearance of the microporosity in certain areas of the sample to form dense blocks whose size increases progressively as a function of the sintering temperature. Mechanical properties were assessed by the Brazilian and Vickers tests. Young and shear moduli were calculated from the longitudinal and transverse ultrasonic velocities, respectively. Above 1300°C, the mechanical strength, Vickers hardness, Young and shear moduli reach maximum values of 30 MPa, 2336 MPa, 81 GPa and 34 GPa, respectively. Rupture of the studied bioceramic is totally intergranular around 1300°C. We find that microstructure, porosity and the sintering process govern the development of the HAP-10%ZrO2bioceramic.

The densification and diametral compression strength of Hydroxyapatite-Zirconia bioceramics: Experimental and modelling studies

Materials Today: Proceedings, 2021

Worldwide, buildings are accountable for a huge share of electrical energy , materials and water ... more Worldwide, buildings are accountable for a huge share of electrical energy , materials and water consumption. Buildings and construction causes for 39% of energy related CO 2 emissions as per world green building council. Aim of Green building is to reduce emissions and also reduce energy consumption by using energy efficient appliances. green building design features have higher initial costs, but the payback period for the incremental investment is less. eco-friendly buildings can grant indirect cost-effective benefits to both the building owner and society in addition to direct cost savings. In this paper design of green building and analysis has been done with BE opt software by considering different parameters.

Élaboration et Caractérisation D'Un Biomatériau À Base De Phosphates De Calcium

Comptes Rendus Physique, 2007

ABSTRACT The tricalcium phosphate–fluorapatite composite has a good aptitude to sintering at 1300... more ABSTRACT The tricalcium phosphate–fluorapatite composite has a good aptitude to sintering at 1300 °C, so a densification rate of about 90% was reached with 33.16 wt% of fluorapatite. At 1300 °C, the increase of the content of fluorapatite in the composite favours the formation of the α tricalcium phosphate phase. The 31P MAS-NMR analysis reveals the presence of three tetrahedral P sites for the tricalcium phosphate, whereas the fluorapatite possesses only one. At temperatures higher than 1300 °C, the densification is hindered by grain growth and the formation of large pores. To cite this article: F. Ben Ayed, J. Bouaziz, C. R. Physique 8 (2007).

Multifunctional and Durable Coatings for Stone Protection Based on Gd-Doped Nanocomposites

Sustainability

The development of nanocomposite materials with multifunctional protective features is an urgent ... more The development of nanocomposite materials with multifunctional protective features is an urgent need in many fields. However, few works have studied the durability of these materials. Even though TiO2 nanoparticles have been extensively applied for self-cleaning effect, it displays a weak activity under visible light. Hence, in this study, pure and Gd-doped TiO2 nanoparticles (molar ratios of doping ions/Ti are 0.1 and 1) were synthesised, characterised, and then mixed with polydimethylsiloxane (PDMS), used as a binder, in order to produce a homogenised thin film on a very porous stone substrate. To our knowledge, Gd-doped TiO2/PDMS protective coatings are studied for the first time for application on historic structures. The protective coatings developed in this work are intended to reduce the surface wettability of the stone and protect the historic stones from dye pollution and microorganism colonisation. Moreover, in this study, the durability of the developed nanocomposite was...

$Figure 1. X-ray diffraction pattern of pure TiO and Gd-doped TiO.$

Synthesis, Characterization and Catalytic Activity of Ternary Oxide Catalysts Using the Microwave-Assisted Solution Combustion Method

Materials

Ni−Co−Al, Ni−Cu−Al and Co−Cu−Al ternary oxide catalysts, with a fixed 5 wt% transition metal load... more Ni−Co−Al, Ni−Cu−Al and Co−Cu−Al ternary oxide catalysts, with a fixed 5 wt% transition metal loading, were prepared by the microwave-assisted solution combustion method and tested in CO oxidation. The bulk and surface properties of the catalysts were investigated, using XRD, N2 adsorption–desorption, SEM, XPS and TEM techniques. XRD, XPS and TEM results revealed that nickel and cobalt were present as spinels on the surface and in the bulk. Differently, copper was preferentially present in “bulk-like” CuO-segregated phases. No interaction between the couples of transition metal species was detected, and the introduction of Cu-containing precursors into the Ni−Al or Co−Al combustion systems was not effective in preventing the formation of NiAl2O4 and CoAl2O4 spinels in the Ni− or Co-containing catalysts. Copper-containing catalysts were the most active, indicating that copper oxides are the effective active species for improving the CO oxidation activity.

Influence of the Fuel/Oxidant Ratio on the Elaboration of Binary Oxide Catalyst by a Microwave-Assisted Solution Combustion Method

Energies

Three series of binary metal oxide catalysts containing Ni, Cu, or Co oxides were prepared, fully... more Three series of binary metal oxide catalysts containing Ni, Cu, or Co oxides were prepared, fully characterized and tested in CO oxidation. The catalysts, with a constant transition metal loading of 10 wt%, were prepared from metal nitrates and urea mixtures by a microwave-assisted solution combustion method. The RV/OV ratio, corresponding to the stoichiometry of the reactants, calculated from their elemental oxidizing and reducing valences, was varied. In order to modify the redox character of the synthesis medium from the quantity of urea; an excess of urea was used for attaining reducing conditions, while a deficit of urea shifted the medium to oxidizing conditions. Three RV/OV ratios (0.9, 1.0, and 1.1) were selected to elaborate the different binary metal oxide catalysts, nine oxide catalysts were synthesized. Then, the influence of the stoichiometry (RV/OV ratio) on the bulk and surface properties of the binary metal oxide catalysts was investigated. Similarly, the influence o...

Effect of the Compositions on the Biocompatibility of New Alumina–Zirconia–Titania Dental Ceramic Composites

Materials

Dental implant biomaterials are expected to be in contact with living tissues, therefore their to... more Dental implant biomaterials are expected to be in contact with living tissues, therefore their toxicity and osseointegration ability must be carefully assessed. In the current study, the wettability, cytotoxicity, and genotoxicity of different alumina–zirconia–titania composites were evaluated. The surface wettability determines the biological event cascade in the bioceramic/human living tissues interface. The measured water contact angle indicated that the wettability strongly depends on the ceramic composition. Notwithstanding the contact angle variability, the ceramic surfaces are hydrophilic. The cytotoxicity of human gingival fibroblast cells with materials, evaluated by an (3-(4,5 methylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) test, revealed an absence of any cytotoxic effect. A relationship was found between the cell viability and the wettability. It was subsequently deduced that the cell viability increases when the wettability increases. This effect is more pron...

Binary Oxides Prepared by Microwave-Assisted Solution Combustion: Synthesis, Characterization and Catalytic Activity

Materials

Three different alumina-based Ni, Cu, Co oxide catalysts with metal loading of 10 wt %, and label... more Three different alumina-based Ni, Cu, Co oxide catalysts with metal loading of 10 wt %, and labeled 10Ni–Al, 10Co–Al and 10Cu–Al, were prepared by microwave-assisted solution combustion. Their morphological, structural and surface properties were deeply investigated by complementary physico-chemical techniques. Finally, the three materials were tested in CO oxidation used as test reaction for comparing their catalytic performance. The 10Cu–Al catalyst was constituted of copper oxide phase, while the 10Ni–Al and 10Co–Al catalysts showed the presence of “spinels” phases on the surface. The well-crystallized copper oxide phase in the 10Cu–Al catalyst, obtained by microwave synthesis, allowed for obtaining very high catalytic activity. With a CO conversion of 100% at 225 °C, the copper containing catalyst showed a much higher activity than that usually measured for catalytic materials of similar composition, thus representing a promising alternative for oxidation processes.

Mechanical and tribological properties of tricalcium phosphate reinforced with fluorapatite as coating for orthopedic implant

Materials Letters

Elaboration of alumina-based materials by solution combustion synthesis: A review

Comptes Rendus Chimie

Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method

Materials science & engineering. C, Materials for biological applications, 2017

In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a... more In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO14 CaO9 POin wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals...

Tricalcium phosphate-Fluorapatite as bone tissue engineering: Evaluation of bioactivity and biocompatibility

Materials science & engineering. C, Materials for biological applications, 2018

Biocomposites consisting of β Tricalcium phosphate (β-TCP) with 26.52% Fluorapatite (Fap) were el... more Biocomposites consisting of β Tricalcium phosphate (β-TCP) with 26.52% Fluorapatite (Fap) were elaborated and characterized in order to evaluate it potential application in bone graft substitute. Bioactivity was determined with in vitro tests by immersion of samples in simulated fluid body for several periods of times. The SEM, EDS and Atomic Absorption Spectroscopy showed the deposition of apatite layer on the surface of samples showing a good bioactivity. However, after 6days of soaking, the dissolution rate of Caand POdecreased which due probably to the improvement of crystallization of the apatite layer. These findings agree with those observed after 6weeks postimplantation of prepared macroporous scaffolds in rabbits. All histological observations of the preliminary in vivo study in the tibia of rabbits proved the biocompatibility and the resorption of the investigated bioceramic. In contrast, the implantation period will have to be optimized by further extensive animal experim...

Prediction performance of compressive strength of cementitious materials containing rubber aggregates and filler using fuzzy logic method

Multidiscipline Modeling in Materials and Structures

Purpose The purpose of this paper is to focus on compressive strength modelling of cementitious m... more Purpose The purpose of this paper is to focus on compressive strength modelling of cementitious mixtures like mortar and Roller-compacted concrete (RCC) containing rubber aggregates from shredded worn tires and filler using adaptive neuro fuzzy inference systems (ANFIS). Design/methodology/approach The volume substitution contains a ratio of rubber aggregates vs sand in mortar and with crushed sand in RCC and ranges from 0 to 50 per cent. As for the filler, they are substituted with sand by 5 per cent in mortar mixture. The methodology consists of optimizing the percentage of substitution in cementitious mixtures to ensure better mechanical properties of materials like compressive strength. The prediction of compressive strength and the optimization of cementitious mixtures encourage their uses in such construction pavements, in area games or in other special constructions. These cementitious materials are considered as friendly to the environment by focussing on their improved defo...

Study of Ceramic Membrane from Naturally Occurring-Kaolin Clays for Microfiltration Applications

Periodica Polytechnica Chemical Engineering

The focus of this work is to assess the quality of porous membranes prepared from naturally occur... more The focus of this work is to assess the quality of porous membranes prepared from naturally occurring kaolin clays and to evaluate the performance of tubular ceramic membranes treating integrated raw effluents from seafood industry. This material has been chosen due to its natural abundance, its non-toxicity, low cost and its valuable properties. The preparation and characterization of porous tubular ceramic membranes, using kaolin powder with and without corn starch as poreforming agent, were reported. SEM photographs indicated that the membrane surface was homogeneous. The effects of material compositions, additives and the relatively lower sintering temperature, ranging from 1100° to 1250°C, on porosity, average pore size, pore-size distribution and mechanical strength of membranes have been investigated. A correlation between microstructure and mechanical properties of membranes has been discussed. The performance of the novel ceramic membranes thus obtained was determined by ev...

$Fig. 2 XRD pattern of the pure kaolin before and after heat treatment (K=Kaolinite; Q=Quartz; I= Illite; M=Mullite) diffractogram due to kaolinite disappeared. This is due to the transformation of kaolinite to amorphous metakaolinite. On the contrary, the peaks of quartz and illite did not change which means the kaolinite phase is only concerned by the thermal treatment at 600°C. At a temperature of 1,250°C, peaks of illite (1) disappeared too, whereas peaks of mullite (M) appeared due to the transformation of metakaolinite. The quartz (Q) peaks remained unchangeable in the diffractogram which confirms the thermal stability of this phase.$

Nanocomposite and nanostructures coatings for LED lighting and photocatalytic applications

International audienc

How Artificial Intelligence Can Improve Our Understanding of the Genes Associated with Endometriosis: Natural Language Processing of the PubMed Database

BioMed Research International, 2018

Endometriosis is a disease characterized by the development of endometrial tissue outside the ute... more Endometriosis is a disease characterized by the development of endometrial tissue outside the uterus, but its cause remains largely unknown. Numerous genes have been studied and proposed to help explain its pathogenesis. However, the large number of these candidate genes has made functional validation through experimental methodologies nearly impossible. Computational methods could provide a useful alternative for prioritizing those most likely to be susceptibility genes. Using artificial intelligence applied to text mining, this study analyzed the genes involved in the pathogenesis, development, and progression of endometriosis. The data extraction by text mining of the endometriosis-related genes in the PubMed database was based on natural language processing, and the data were filtered to remove false positives. Using data from the text mining and gene network information as input for the web-based tool, 15,207 endometriosis-related genes were ranked according to their score in t...

Performance Enhancement of Kaolin/Chitosan Composite-Based Membranes by Cross-Linking with Sodium Tripolyphosphate: Preparation and Characterization

Membranes

A new family of environmentally friendly and low-cost membranes based on readily available minera... more A new family of environmentally friendly and low-cost membranes based on readily available mineral and polymeric materials has been developed from cast suspensions of kaolin and chitosan using aqueous phase separation and polyethylene glycol as a pore-forming agent. The as-fabricated membranes were further cross-linked with sodium tripolyphosphate (STPP) in order to strengthen the properties of the obtained samples. The functional groups determined by FTIR and EDX confirmed that the reaction occurred. A detailed study of the effects of cross-linking time on the physicochemical, surface and permeation properties showed that a 30-minute reaction enabled the composite membrane to be stable in acidic media (up to pH 2) and increased the mechanical strength twofold compared to the non-cross-linked membrane. A similar morphology to that generally observed in polymeric membranes was obtained, with a sponge-like surface overlaying a finger-like through structure. The top layer and cross-sec...

Characterization of tricalcium phosphate-fluorapatite ceramics composites by ultrasonic testing

Faraday Effect in Doped Aerogels

Le Journal de Physique Colloques, 1989

prepares par l a m6thode s o l-g e l &I p a r t i r des n i t r a t e s de dysprosium ou d'erbium... more prepares par l a m6thode s o l-g e l &I p a r t i r des n i t r a t e s de dysprosium ou d'erbium e t de tBtram6thoxysilane (TMOS). Des aerogels avec des c o n c e n t r a t i o n s 4lev6es en 1 anthani des (14% mol a i r e) o n t 6 t 6 obtenus. Les constantes de Verdet de ces aerogels o n t B t 6 determinees.

Valorization of Marine Sediments in a Proteinic Biopolymer: Modeling of the Mechanical Behavior

J Polym Environ, 2014

Biocomposites, which consist of renewable resources like proteins, have been extensively investig... more Biocomposites, which consist of renewable resources like proteins, have been extensively investigated. However, studies on the combination of marine sediments and proteinic biopolymer have not been conducted yet. In this work, marine sediments were added to the matrix in proportions ranging from 0 to 20 %. The mechanical properties in terms of tensile, flexural and compressive strength tests were investigated. Thermogravimetric analysis were also used to assess the thermal stability of the produced composites. The hemoglobin marine sediments (HESM) may be dedicated to ground coating or to wall covering, it is then necessary to perform a preliminary structure analysis. A multi-phase mechanical model able to reproduce the compressive behavior of the HESM is developed in order to simulate the HESM coating at different marine sediments ratios and different strain rates. The incorporation of sediments increases the stiffness of the material and improves the compressive properties of the composite.

Effect of the surface chemistry on the stability and mechanical properties of the Zirconia-Hydroxyapatite bioceramic

Surfaces and Interfaces, 2021

Abstract Hydroxyapatite/zirconia powders were produced by soft chemistry and characterized by sev... more Abstract Hydroxyapatite/zirconia powders were produced by soft chemistry and characterized by several techniques. The effects of the sintering temperature on the densification, microstructure and mechanical properties of the bioceramics were studied. The HAP-10%ZrO2 bioceramic was chosen for its specific advantages. Microstructural and textural characterization reveal disappearance of the microporosity in certain areas of the sample to form dense blocks whose size increases progressively as a function of the sintering temperature. Mechanical properties were assessed by the Brazilian and Vickers tests. Young and shear moduli were calculated from the longitudinal and transverse ultrasonic velocities, respectively. Above 1300°C, the mechanical strength, Vickers hardness, Young and shear moduli reach maximum values of 30 MPa, 2336 MPa, 81 GPa and 34 GPa, respectively. Rupture of the studied bioceramic is totally intergranular around 1300°C. We find that microstructure, porosity and the sintering process govern the development of the HAP-10%ZrO2bioceramic.

The densification and diametral compression strength of Hydroxyapatite-Zirconia bioceramics: Experimental and modelling studies

Materials Today: Proceedings, 2021

Worldwide, buildings are accountable for a huge share of electrical energy , materials and water ... more Worldwide, buildings are accountable for a huge share of electrical energy , materials and water consumption. Buildings and construction causes for 39% of energy related CO 2 emissions as per world green building council. Aim of Green building is to reduce emissions and also reduce energy consumption by using energy efficient appliances. green building design features have higher initial costs, but the payback period for the incremental investment is less. eco-friendly buildings can grant indirect cost-effective benefits to both the building owner and society in addition to direct cost savings. In this paper design of green building and analysis has been done with BE opt software by considering different parameters.

Élaboration et Caractérisation D'Un Biomatériau À Base De Phosphates De Calcium

Comptes Rendus Physique, 2007

ABSTRACT The tricalcium phosphate–fluorapatite composite has a good aptitude to sintering at 1300... more ABSTRACT The tricalcium phosphate–fluorapatite composite has a good aptitude to sintering at 1300 °C, so a densification rate of about 90% was reached with 33.16 wt% of fluorapatite. At 1300 °C, the increase of the content of fluorapatite in the composite favours the formation of the α tricalcium phosphate phase. The 31P MAS-NMR analysis reveals the presence of three tetrahedral P sites for the tricalcium phosphate, whereas the fluorapatite possesses only one. At temperatures higher than 1300 °C, the densification is hindered by grain growth and the formation of large pores. To cite this article: F. Ben Ayed, J. Bouaziz, C. R. Physique 8 (2007).

Multifunctional and Durable Coatings for Stone Protection Based on Gd-Doped Nanocomposites

Sustainability

The development of nanocomposite materials with multifunctional protective features is an urgent ... more The development of nanocomposite materials with multifunctional protective features is an urgent need in many fields. However, few works have studied the durability of these materials. Even though TiO2 nanoparticles have been extensively applied for self-cleaning effect, it displays a weak activity under visible light. Hence, in this study, pure and Gd-doped TiO2 nanoparticles (molar ratios of doping ions/Ti are 0.1 and 1) were synthesised, characterised, and then mixed with polydimethylsiloxane (PDMS), used as a binder, in order to produce a homogenised thin film on a very porous stone substrate. To our knowledge, Gd-doped TiO2/PDMS protective coatings are studied for the first time for application on historic structures. The protective coatings developed in this work are intended to reduce the surface wettability of the stone and protect the historic stones from dye pollution and microorganism colonisation. Moreover, in this study, the durability of the developed nanocomposite was...

$Figure 1. X-ray diffraction pattern of pure TiO and Gd-doped TiO.$

Synthesis, Characterization and Catalytic Activity of Ternary Oxide Catalysts Using the Microwave-Assisted Solution Combustion Method

Materials

Ni−Co−Al, Ni−Cu−Al and Co−Cu−Al ternary oxide catalysts, with a fixed 5 wt% transition metal load... more Ni−Co−Al, Ni−Cu−Al and Co−Cu−Al ternary oxide catalysts, with a fixed 5 wt% transition metal loading, were prepared by the microwave-assisted solution combustion method and tested in CO oxidation. The bulk and surface properties of the catalysts were investigated, using XRD, N2 adsorption–desorption, SEM, XPS and TEM techniques. XRD, XPS and TEM results revealed that nickel and cobalt were present as spinels on the surface and in the bulk. Differently, copper was preferentially present in “bulk-like” CuO-segregated phases. No interaction between the couples of transition metal species was detected, and the introduction of Cu-containing precursors into the Ni−Al or Co−Al combustion systems was not effective in preventing the formation of NiAl2O4 and CoAl2O4 spinels in the Ni− or Co-containing catalysts. Copper-containing catalysts were the most active, indicating that copper oxides are the effective active species for improving the CO oxidation activity.

Influence of the Fuel/Oxidant Ratio on the Elaboration of Binary Oxide Catalyst by a Microwave-Assisted Solution Combustion Method

Energies

Three series of binary metal oxide catalysts containing Ni, Cu, or Co oxides were prepared, fully... more Three series of binary metal oxide catalysts containing Ni, Cu, or Co oxides were prepared, fully characterized and tested in CO oxidation. The catalysts, with a constant transition metal loading of 10 wt%, were prepared from metal nitrates and urea mixtures by a microwave-assisted solution combustion method. The RV/OV ratio, corresponding to the stoichiometry of the reactants, calculated from their elemental oxidizing and reducing valences, was varied. In order to modify the redox character of the synthesis medium from the quantity of urea; an excess of urea was used for attaining reducing conditions, while a deficit of urea shifted the medium to oxidizing conditions. Three RV/OV ratios (0.9, 1.0, and 1.1) were selected to elaborate the different binary metal oxide catalysts, nine oxide catalysts were synthesized. Then, the influence of the stoichiometry (RV/OV ratio) on the bulk and surface properties of the binary metal oxide catalysts was investigated. Similarly, the influence o...

Effect of the Compositions on the Biocompatibility of New Alumina–Zirconia–Titania Dental Ceramic Composites

Materials

Dental implant biomaterials are expected to be in contact with living tissues, therefore their to... more Dental implant biomaterials are expected to be in contact with living tissues, therefore their toxicity and osseointegration ability must be carefully assessed. In the current study, the wettability, cytotoxicity, and genotoxicity of different alumina–zirconia–titania composites were evaluated. The surface wettability determines the biological event cascade in the bioceramic/human living tissues interface. The measured water contact angle indicated that the wettability strongly depends on the ceramic composition. Notwithstanding the contact angle variability, the ceramic surfaces are hydrophilic. The cytotoxicity of human gingival fibroblast cells with materials, evaluated by an (3-(4,5 methylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) test, revealed an absence of any cytotoxic effect. A relationship was found between the cell viability and the wettability. It was subsequently deduced that the cell viability increases when the wettability increases. This effect is more pron...

Binary Oxides Prepared by Microwave-Assisted Solution Combustion: Synthesis, Characterization and Catalytic Activity

Materials

Three different alumina-based Ni, Cu, Co oxide catalysts with metal loading of 10 wt %, and label... more Three different alumina-based Ni, Cu, Co oxide catalysts with metal loading of 10 wt %, and labeled 10Ni–Al, 10Co–Al and 10Cu–Al, were prepared by microwave-assisted solution combustion. Their morphological, structural and surface properties were deeply investigated by complementary physico-chemical techniques. Finally, the three materials were tested in CO oxidation used as test reaction for comparing their catalytic performance. The 10Cu–Al catalyst was constituted of copper oxide phase, while the 10Ni–Al and 10Co–Al catalysts showed the presence of “spinels” phases on the surface. The well-crystallized copper oxide phase in the 10Cu–Al catalyst, obtained by microwave synthesis, allowed for obtaining very high catalytic activity. With a CO conversion of 100% at 225 °C, the copper containing catalyst showed a much higher activity than that usually measured for catalytic materials of similar composition, thus representing a promising alternative for oxidation processes.

Mechanical and tribological properties of tricalcium phosphate reinforced with fluorapatite as coating for orthopedic implant

Materials Letters

Elaboration of alumina-based materials by solution combustion synthesis: A review

Comptes Rendus Chimie

Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method

Materials science & engineering. C, Materials for biological applications, 2017

In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a... more In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO14 CaO9 POin wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals...

Tricalcium phosphate-Fluorapatite as bone tissue engineering: Evaluation of bioactivity and biocompatibility

Materials science & engineering. C, Materials for biological applications, 2018

Biocomposites consisting of β Tricalcium phosphate (β-TCP) with 26.52% Fluorapatite (Fap) were el... more Biocomposites consisting of β Tricalcium phosphate (β-TCP) with 26.52% Fluorapatite (Fap) were elaborated and characterized in order to evaluate it potential application in bone graft substitute. Bioactivity was determined with in vitro tests by immersion of samples in simulated fluid body for several periods of times. The SEM, EDS and Atomic Absorption Spectroscopy showed the deposition of apatite layer on the surface of samples showing a good bioactivity. However, after 6days of soaking, the dissolution rate of Caand POdecreased which due probably to the improvement of crystallization of the apatite layer. These findings agree with those observed after 6weeks postimplantation of prepared macroporous scaffolds in rabbits. All histological observations of the preliminary in vivo study in the tibia of rabbits proved the biocompatibility and the resorption of the investigated bioceramic. In contrast, the implantation period will have to be optimized by further extensive animal experim...

Prediction performance of compressive strength of cementitious materials containing rubber aggregates and filler using fuzzy logic method

Multidiscipline Modeling in Materials and Structures

Purpose The purpose of this paper is to focus on compressive strength modelling of cementitious m... more Purpose The purpose of this paper is to focus on compressive strength modelling of cementitious mixtures like mortar and Roller-compacted concrete (RCC) containing rubber aggregates from shredded worn tires and filler using adaptive neuro fuzzy inference systems (ANFIS). Design/methodology/approach The volume substitution contains a ratio of rubber aggregates vs sand in mortar and with crushed sand in RCC and ranges from 0 to 50 per cent. As for the filler, they are substituted with sand by 5 per cent in mortar mixture. The methodology consists of optimizing the percentage of substitution in cementitious mixtures to ensure better mechanical properties of materials like compressive strength. The prediction of compressive strength and the optimization of cementitious mixtures encourage their uses in such construction pavements, in area games or in other special constructions. These cementitious materials are considered as friendly to the environment by focussing on their improved defo...

Study of Ceramic Membrane from Naturally Occurring-Kaolin Clays for Microfiltration Applications

Periodica Polytechnica Chemical Engineering

The focus of this work is to assess the quality of porous membranes prepared from naturally occur... more The focus of this work is to assess the quality of porous membranes prepared from naturally occurring kaolin clays and to evaluate the performance of tubular ceramic membranes treating integrated raw effluents from seafood industry. This material has been chosen due to its natural abundance, its non-toxicity, low cost and its valuable properties. The preparation and characterization of porous tubular ceramic membranes, using kaolin powder with and without corn starch as poreforming agent, were reported. SEM photographs indicated that the membrane surface was homogeneous. The effects of material compositions, additives and the relatively lower sintering temperature, ranging from 1100° to 1250°C, on porosity, average pore size, pore-size distribution and mechanical strength of membranes have been investigated. A correlation between microstructure and mechanical properties of membranes has been discussed. The performance of the novel ceramic membranes thus obtained was determined by ev...

$Fig. 2 XRD pattern of the pure kaolin before and after heat treatment (K=Kaolinite; Q=Quartz; I= Illite; M=Mullite) diffractogram due to kaolinite disappeared. This is due to the transformation of kaolinite to amorphous metakaolinite. On the contrary, the peaks of quartz and illite did not change which means the kaolinite phase is only concerned by the thermal treatment at 600°C. At a temperature of 1,250°C, peaks of illite (1) disappeared too, whereas peaks of mullite (M) appeared due to the transformation of metakaolinite. The quartz (Q) peaks remained unchangeable in the diffractogram which confirms the thermal stability of this phase.$