The impact of a high molecule organic compound containing amine fragment (HMoA) on the corrosion ... more The impact of a high molecule organic compound containing amine fragment (HMoA) on the corrosion and electrochemical behaviors of carbon steel (CSA516), ferritic (SS410) and austenitic (SS304L) stainless steels was studied in the environment of the LAO (linear α-olefin) plant. Corrosion tests were carried out at 270 oC and 29 bar in an autoclave at different exposure time intervals (up to 30 days). Corrosion rates were determined using mass losses of the samples with and without HMoA. Optical microscopy (OM) and scanning electron microscopy (SEM) were employed to assess the morphologies of the corroded and inhibited surfaces. Efficiency and kinetics of electrode processes in the presence of HMoA were investigated by means of polarization and impedance measurements. Results of these experimental data are widely presented and discussed in this paper. It was found that the inhibition performance of the tested compound recorded inhibition efficiencies of 30%, 66% and 95% for CSA516, SS4...
ABSTRACT A series of Zn1–xNixFe2O4 nano ferrite (with x=0, 0.2, 0.4, 0.6, 0.8, and 1) composition... more ABSTRACT A series of Zn1–xNixFe2O4 nano ferrite (with x=0, 0.2, 0.4, 0.6, 0.8, and 1) compositions were synthesized using the combustion technique. The powder samples were characterized by XRD. The X-ray analysis showed that the samples were single phase spinel cubic structure. The AC resistivity decreases by increasing the frequency from 1 kHz to 10 kHz. As the frequency of the applied field increases the hopping of charge carrier also increase, thereby decreasing the resistivity. A shift in dielectric maximum is observed toward higher temperature with increasing the Ni content from 536 K to 560 K at 1 kHz. The HRTEM (high resolution TEM) images of four compositions have lattice spacing which confirms the crystalline nature of the samples. The surface morphology SEM of the sample consists of some grains with relatively homogenies distribution with an average size varying from 0.85 to 0.92 μm. The values for entropy change in this work are still small but are significally higher than the values that have been reported for iron oxide nanoparticle. The magnetic entropy change was calculated from measurements of M (H, T) where H is the magnetic field and T is the temperature. The maximum value of entropy change (∆S) obtained near Curie temperature which makes these material candidates for magnetocaloric applications.
Zinc ferrite nanoparticles were prepared via thermal treatment of their mixed hydroxides at 400°C... more Zinc ferrite nanoparticles were prepared via thermal treatment of their mixed hydroxides at 400°C-600°C. The mixed hydroxides were co-precipitated from their nitrates solutions using NaOH as precipitating agent. The effects of pH and calcination temperature on the microstructure of the prepared system were studied using X-ray powder diffraction and Mössbauer spectroscopy. The crystallite sizes of the synthetic ferrite ranges between 12-48 nm respectively. The crystallite size of each sample was found to be strongly dependent on the calcination temperature and pH. Moreover, the Mössbauer profile of Zinc ferrite phase is discussed in terms of the particle size and the measuring Mössbauer temperature.
International Journal of Materials and Chemistry, 2012
In this work we present the experimental results on synthesis structure and in vitro bioactivity ... more In this work we present the experimental results on synthesis structure and in vitro bioactivity of collagen (C)/calcium phosphate silicate (CPS)/chondroitin sulfate (ChS) composites with C/CPS ratio of 25:75 wt. % and 75:25wt. %. The synthesized composites were characterized by XRD, FTIR and SEM/EDS. XRD and FTIR before in vitro test proved that the carbonate containing hydroxyapatite (CO 3 HA) formed in situ. After in vitro test for 3 days in 1.5 SBF, the nucleation of B-type CO 3 HA was estimated on the obtained C/CPS=75:25 wt. % composite with cauliflower-like assembly. On the C/CPS=25:75 wt. % amorphous hydroxyapatite (HA) layer was observed.
ZnO could be rapidly synthesis by microwave hydrothermal hydrolysis of [Zn(en) 3 ](NO 3 ) 2 compl... more ZnO could be rapidly synthesis by microwave hydrothermal hydrolysis of [Zn(en) 3 ](NO 3 ) 2 complex. The morphology of ZnO could be controlled by changing the pH. Flower-like ZnO morphology prepared at pH = 10 and 12. Rod-like ZnO morphology prepared at pH = 7. The band gap and optical properties of ZnO was found to be dependent on its morphology.
Mo-substituted cobalt ferrite nanoparticles; CoFe 2 À 2x Mo x O 4 (0.0 rx r 0.3) were prepared by... more Mo-substituted cobalt ferrite nanoparticles; CoFe 2 À 2x Mo x O 4 (0.0 rx r 0.3) were prepared by a one-step solution combustion synthesis technique. The reactants were metal nitrates and glycine as a fuel. The samples were characterized using an X-ray diffraction (XRD), a transmission electron microscope (TEM) and a vibrating sample magnetometer (VSM). XRD analysis revealed a pure single phase of cubic spinel ferrites for all samples with x up to 0.3. The lattice parameter decreases with Mo 6 þ substitution linearly up to x ¼0.15, then nonlinearly for x Z0.2. Rietveld analysis and saturation magnetization (M s ) revealed that Mo 6 þ replaced Fe 3 þ in the tetrahedral A-sites up to x ¼0.15, then it replaced Fe 3 þ in both A-sites and B-sites for x Z 0.2. The saturation magnetization (M s ) increases with increasing Mo 6 þ substitution up to x ¼ 0.15 then decreases. The crystallite size decreased while the microstrain increased with increasing Mo 6 þ substitution. Inserting Mo 6 þ produces large residents of defects and cation vacancies.
In this study, the biosynthesis of silver nanoparticles using supernatant of Alcaligenes faecalis... more In this study, the biosynthesis of silver nanoparticles using supernatant of Alcaligenes faecalis was described. UV-Vis absorption spectra showed the reduction of silver ions to silver nanoparticles with a surface Plasmon resonance (SPR) band centered at 455 nm. The TEM analysis revealed the formation of spherical, and monodispersed nanoparticles with an average size of 11 nm. The silver nanoparticles were stabilized by the capping of protein present in the culture supernatant as revealed by FT-IR spectral analysis. Synthesized nanoparticles showed efficacy on antibacterial property against clinically isolated multi-drug resistant (MDR) microorganisms. This study also demonstrates that nanoparticles synthesis could be controlled by varying the parameters such as temperature and pH. It is suggested that biogenic synthesis of nanoparticles have wide-application in medicine and physical chemistry and it can produce with eco-friendly, easy downstream processing and rapid scale-up processing.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2012
This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a... more This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a fundamental parameter approach. C. edulis is a famous drug plant in east Africa and Arabian Peninsula. We have previously confirmed that hydroxyapatite represents one of the main inorganic compounds in the leaves and stalks of C. edulis. Comparable plant leaves from basil, mint and green tea were included in the present investigation as well as trifolium leaves were included as a non-related plant. The elemental analyses of the plants were done by Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectroscopy. Standard-less quantitative WDXRF analysis was carried out based on the fundamental parameter approaches. According to the standard-less analysis algorithms, there is an essential need for an accurate determination of the amount of organic material in the sample. A new approach, based on the differential thermal analysis, was successfully used for the organic material determination. The obtained results based on this approach were in a good agreement with the commonly used methods. Depending on the developed method, quantitative analysis results of eighteen elements including; Al, Br, Ca, Cl, Cu, Fe, K, Na, Ni, Mg, Mn, P, Rb, S, Si, Sr, Ti and Zn were obtained for each plant. The results of the certified reference materials of green tea (NCSZC73014, China National Analysis Center for Iron and Steel, Beijing, China) confirmed the validity of the proposed method.
The structural and magnetic properties of epitaxial In 1Àx Mn x As 1Ày P y quaternary layers with... more The structural and magnetic properties of epitaxial In 1Àx Mn x As 1Ày P y quaternary layers with Mn content ranging from 0.01 to 0.04 and phosphorous content ranging from 0.11 to 0.21 were studied. X-ray diffraction indicated that the films were two phase consisting of an InMnAsP solid solution and hexagonal MnAs nanoprecipitates. Addition of phosphorus promoted precipitate formation. Films were ferromagnetic showing hysteretic behavior in the field dependence of magnetization at 5 and 298 K. From field-cooled magnetization measurements ferromagnetic transitions were observed at 280 and 325 K. The zero field-cooled magnetization versus temperature measurements showed irreversibility for To300 K that was attributed to the presence of MnAs nanoprecipitates. The calculated coercivity using the Neel model was 1380 G compared to the experimental value of 380 G at 5 K. The difference was attributed to a strong inter-cluster exchange that stabilizes the ferromagnetic state.
Cd-substituted manganese ferrite Mn 1 À x Cd x Fe 2 O 4 powders with x having values 0.0, 0.1, 0.... more Cd-substituted manganese ferrite Mn 1 À x Cd x Fe 2 O 4 powders with x having values 0.0, 0.1, 0.3 and 0.5 have been synthesized by hydrothermal route at 180 1C in presence of NaOH as mineralizer. The obtained ferrite samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The XRD analysis showed that pure single phases of cubic ferrites were obtained with x upto 0.3. However, sample with xZ0.5 showed hexagonal phase of cadmium hydroxide (Cd(OH) 2 ) besides the ferrite phase. The increase in Cd-substitution upto x¼0.3 leads to an increase in the lattice parameter as well as the average crystallite size of the prepared ferrites. The average crystallite size increased by increasing the Cd-content and was in the range of 39-57 nm. According to VSM results, the saturation magnetization increased with Cd ion substitution.
The impact of a high molecule organic compound containing amine fragment (HMoA) on the corrosion ... more The impact of a high molecule organic compound containing amine fragment (HMoA) on the corrosion and electrochemical behaviors of carbon steel (CSA516), ferritic (SS410) and austenitic (SS304L) stainless steels was studied in the environment of the LAO (linear α-olefin) plant. Corrosion tests were carried out at 270 oC and 29 bar in an autoclave at different exposure time intervals (up to 30 days). Corrosion rates were determined using mass losses of the samples with and without HMoA. Optical microscopy (OM) and scanning electron microscopy (SEM) were employed to assess the morphologies of the corroded and inhibited surfaces. Efficiency and kinetics of electrode processes in the presence of HMoA were investigated by means of polarization and impedance measurements. Results of these experimental data are widely presented and discussed in this paper. It was found that the inhibition performance of the tested compound recorded inhibition efficiencies of 30%, 66% and 95% for CSA516, SS4...
ABSTRACT A series of Zn1–xNixFe2O4 nano ferrite (with x=0, 0.2, 0.4, 0.6, 0.8, and 1) composition... more ABSTRACT A series of Zn1–xNixFe2O4 nano ferrite (with x=0, 0.2, 0.4, 0.6, 0.8, and 1) compositions were synthesized using the combustion technique. The powder samples were characterized by XRD. The X-ray analysis showed that the samples were single phase spinel cubic structure. The AC resistivity decreases by increasing the frequency from 1 kHz to 10 kHz. As the frequency of the applied field increases the hopping of charge carrier also increase, thereby decreasing the resistivity. A shift in dielectric maximum is observed toward higher temperature with increasing the Ni content from 536 K to 560 K at 1 kHz. The HRTEM (high resolution TEM) images of four compositions have lattice spacing which confirms the crystalline nature of the samples. The surface morphology SEM of the sample consists of some grains with relatively homogenies distribution with an average size varying from 0.85 to 0.92 μm. The values for entropy change in this work are still small but are significally higher than the values that have been reported for iron oxide nanoparticle. The magnetic entropy change was calculated from measurements of M (H, T) where H is the magnetic field and T is the temperature. The maximum value of entropy change (∆S) obtained near Curie temperature which makes these material candidates for magnetocaloric applications.
Zinc ferrite nanoparticles were prepared via thermal treatment of their mixed hydroxides at 400°C... more Zinc ferrite nanoparticles were prepared via thermal treatment of their mixed hydroxides at 400°C-600°C. The mixed hydroxides were co-precipitated from their nitrates solutions using NaOH as precipitating agent. The effects of pH and calcination temperature on the microstructure of the prepared system were studied using X-ray powder diffraction and Mössbauer spectroscopy. The crystallite sizes of the synthetic ferrite ranges between 12-48 nm respectively. The crystallite size of each sample was found to be strongly dependent on the calcination temperature and pH. Moreover, the Mössbauer profile of Zinc ferrite phase is discussed in terms of the particle size and the measuring Mössbauer temperature.
International Journal of Materials and Chemistry, 2012
In this work we present the experimental results on synthesis structure and in vitro bioactivity ... more In this work we present the experimental results on synthesis structure and in vitro bioactivity of collagen (C)/calcium phosphate silicate (CPS)/chondroitin sulfate (ChS) composites with C/CPS ratio of 25:75 wt. % and 75:25wt. %. The synthesized composites were characterized by XRD, FTIR and SEM/EDS. XRD and FTIR before in vitro test proved that the carbonate containing hydroxyapatite (CO 3 HA) formed in situ. After in vitro test for 3 days in 1.5 SBF, the nucleation of B-type CO 3 HA was estimated on the obtained C/CPS=75:25 wt. % composite with cauliflower-like assembly. On the C/CPS=25:75 wt. % amorphous hydroxyapatite (HA) layer was observed.
ZnO could be rapidly synthesis by microwave hydrothermal hydrolysis of [Zn(en) 3 ](NO 3 ) 2 compl... more ZnO could be rapidly synthesis by microwave hydrothermal hydrolysis of [Zn(en) 3 ](NO 3 ) 2 complex. The morphology of ZnO could be controlled by changing the pH. Flower-like ZnO morphology prepared at pH = 10 and 12. Rod-like ZnO morphology prepared at pH = 7. The band gap and optical properties of ZnO was found to be dependent on its morphology.
Mo-substituted cobalt ferrite nanoparticles; CoFe 2 À 2x Mo x O 4 (0.0 rx r 0.3) were prepared by... more Mo-substituted cobalt ferrite nanoparticles; CoFe 2 À 2x Mo x O 4 (0.0 rx r 0.3) were prepared by a one-step solution combustion synthesis technique. The reactants were metal nitrates and glycine as a fuel. The samples were characterized using an X-ray diffraction (XRD), a transmission electron microscope (TEM) and a vibrating sample magnetometer (VSM). XRD analysis revealed a pure single phase of cubic spinel ferrites for all samples with x up to 0.3. The lattice parameter decreases with Mo 6 þ substitution linearly up to x ¼0.15, then nonlinearly for x Z0.2. Rietveld analysis and saturation magnetization (M s ) revealed that Mo 6 þ replaced Fe 3 þ in the tetrahedral A-sites up to x ¼0.15, then it replaced Fe 3 þ in both A-sites and B-sites for x Z 0.2. The saturation magnetization (M s ) increases with increasing Mo 6 þ substitution up to x ¼ 0.15 then decreases. The crystallite size decreased while the microstrain increased with increasing Mo 6 þ substitution. Inserting Mo 6 þ produces large residents of defects and cation vacancies.
In this study, the biosynthesis of silver nanoparticles using supernatant of Alcaligenes faecalis... more In this study, the biosynthesis of silver nanoparticles using supernatant of Alcaligenes faecalis was described. UV-Vis absorption spectra showed the reduction of silver ions to silver nanoparticles with a surface Plasmon resonance (SPR) band centered at 455 nm. The TEM analysis revealed the formation of spherical, and monodispersed nanoparticles with an average size of 11 nm. The silver nanoparticles were stabilized by the capping of protein present in the culture supernatant as revealed by FT-IR spectral analysis. Synthesized nanoparticles showed efficacy on antibacterial property against clinically isolated multi-drug resistant (MDR) microorganisms. This study also demonstrates that nanoparticles synthesis could be controlled by varying the parameters such as temperature and pH. It is suggested that biogenic synthesis of nanoparticles have wide-application in medicine and physical chemistry and it can produce with eco-friendly, easy downstream processing and rapid scale-up processing.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2012
This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a... more This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a fundamental parameter approach. C. edulis is a famous drug plant in east Africa and Arabian Peninsula. We have previously confirmed that hydroxyapatite represents one of the main inorganic compounds in the leaves and stalks of C. edulis. Comparable plant leaves from basil, mint and green tea were included in the present investigation as well as trifolium leaves were included as a non-related plant. The elemental analyses of the plants were done by Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectroscopy. Standard-less quantitative WDXRF analysis was carried out based on the fundamental parameter approaches. According to the standard-less analysis algorithms, there is an essential need for an accurate determination of the amount of organic material in the sample. A new approach, based on the differential thermal analysis, was successfully used for the organic material determination. The obtained results based on this approach were in a good agreement with the commonly used methods. Depending on the developed method, quantitative analysis results of eighteen elements including; Al, Br, Ca, Cl, Cu, Fe, K, Na, Ni, Mg, Mn, P, Rb, S, Si, Sr, Ti and Zn were obtained for each plant. The results of the certified reference materials of green tea (NCSZC73014, China National Analysis Center for Iron and Steel, Beijing, China) confirmed the validity of the proposed method.
The structural and magnetic properties of epitaxial In 1Àx Mn x As 1Ày P y quaternary layers with... more The structural and magnetic properties of epitaxial In 1Àx Mn x As 1Ày P y quaternary layers with Mn content ranging from 0.01 to 0.04 and phosphorous content ranging from 0.11 to 0.21 were studied. X-ray diffraction indicated that the films were two phase consisting of an InMnAsP solid solution and hexagonal MnAs nanoprecipitates. Addition of phosphorus promoted precipitate formation. Films were ferromagnetic showing hysteretic behavior in the field dependence of magnetization at 5 and 298 K. From field-cooled magnetization measurements ferromagnetic transitions were observed at 280 and 325 K. The zero field-cooled magnetization versus temperature measurements showed irreversibility for To300 K that was attributed to the presence of MnAs nanoprecipitates. The calculated coercivity using the Neel model was 1380 G compared to the experimental value of 380 G at 5 K. The difference was attributed to a strong inter-cluster exchange that stabilizes the ferromagnetic state.
Cd-substituted manganese ferrite Mn 1 À x Cd x Fe 2 O 4 powders with x having values 0.0, 0.1, 0.... more Cd-substituted manganese ferrite Mn 1 À x Cd x Fe 2 O 4 powders with x having values 0.0, 0.1, 0.3 and 0.5 have been synthesized by hydrothermal route at 180 1C in presence of NaOH as mineralizer. The obtained ferrite samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The XRD analysis showed that pure single phases of cubic ferrites were obtained with x upto 0.3. However, sample with xZ0.5 showed hexagonal phase of cadmium hydroxide (Cd(OH) 2 ) besides the ferrite phase. The increase in Cd-substitution upto x¼0.3 leads to an increase in the lattice parameter as well as the average crystallite size of the prepared ferrites. The average crystallite size increased by increasing the Cd-content and was in the range of 39-57 nm. According to VSM results, the saturation magnetization increased with Cd ion substitution.
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