Simple and eco-friendly method was developed for synthesis of silver nanoparticles (Ag NPs) via reduction of Ag+ by aqueous Grape leaves extract (GLE). Temperature induced synthesis of Ag NPs was performed and compared to photo-irradiation based method. Formation of Ag NPs was elucidated by both UV–vis spectroscopy and the change of color of the aqueous solution. The formation of Ag NPs is highly influenced by the reaction temperature. The higher the reaction temperature, the faster is the formation of Ag NPs. Phase composition, lattice strain and crystallinity of Ag NPs were analyzed by XRD. The prepared Ag NPs are stabilized by the presence of organic compounds originating from GLE which was proved by both XRD and FTIR analysis. TEM investigation of the synthesized Ag NPs showed that they are highly crystalline in nature and have sphere-like morphology with an average diameter of ~20 nm. The obtained Ag NPs showed efficient antibacterial activity against some Gram +ve and Gram –ve bacteria, particularly Staphylococcus aureus (+ve) and Pseudomonas aeruginosa (−ve).

Simple and eco-friendly method was developed for synthesis of silver nanoparticles (Ag NPs) via reduction of Ag+ by aqueous Grape leaves extract (GLE). Temperature induced synthesis of Ag NPs was performed and compared to photo-irradiation based method. Formation of Ag NPs was elucidated by both UV–vis spectroscopy and the change of color of the aqueous solution. The formation of Ag NPs is highly influenced by the reaction temperature. The higher the reaction temperature, the faster is the formation of Ag NPs. Phase composition, lattice strain and crystallinity of Ag NPs were analyzed by XRD. The prepared Ag NPs are stabilized by the presence of organic compounds originating from GLE which was proved by both XRD and FTIR analysis. TEM investigation of the synthesized Ag NPs showed that they are highly crystalline in nature and have sphere-like morphology with an average diameter of ~20 nm. The obtained Ag NPs showed efficient antibacterial activity against some Gram +ve and Gram –ve bacteria, particularly Staphylococcus aureus (+ve) and Pseudomonas aeruginosa (−ve).

Identification of defect chemistry and variation of particle size are key factors for understanding many intrinsic properties of materials. Herein, size selective synthesis of Mn3O4 nanoparticles was performed by precipitation of Mn(OH)2 via NaOH or ammonia followed by air oxidation in ethanol/water solution. The amount of ethanol in water affects the average particle size that drops from ~25 nm in pure water to ~10 nm in 95% EtOH/H2O. TEM studies showed that the Mn3O4 samples have a sphere-cube like morphologies. Calculation of SOF and unit cell parameters via Rietveld analysis and the excess mass of Mn3O4 samples depending on size by TGA and IR revealed that the cationic deficiency observed in the structure of the smallest size sample is compensated mainly by anionic vacancies. Ideal spinel structure was found for largest size sample. The degree of tetragonal distortion (c/√2 a) of Mn3O4 unit cell increases with particle size.

Two different MnO2polymorphs, namely akhtenskite (ε-form) and nsutite (g-form) were obtained fromthe comproportionation reaction between Mn2þand MnO4. The conditions that administer the trans-formation between both phases i.e. temperature, reflux time and concentration of reactants wereexplored. Other manganese oxide/hydroxide phases are obtained depending on variation of the pH of themedium or the solvent used in the reaction. Heat-treatment of both MnO2polymorphs was done underisothermal and non-isothermal conditions, various pathways were adopted in both cases. The results ofTGA/DTA analysis showed also thatg-MnO2is more stable thanε- MnO2and thatε-form contains muchmore excess mass over its surface (i.e. surface bound hydroxyl groups) thang-form. Surface area mea-surements revealed that the reaction temperature has pronounced effect not only on the product phasebut also on its surface properties. Very high surface area of 345 cm2/g was adopted byε-MnO2anddecreases with increasing of reaction time (239 m2/g). SEM investigations showed thatg-MnO2has aplate-like shape whilstε-MnO2exhibits a sponge-like morphology. Magnetic properties of both oxideswere explored using SQUID magnetometer under zerofield cooled andfield cooled conditions. Bothphases showed a ferromagnetic spin ordering with Curie temperature as 45 K forg-form and 20 K forε-form. The coercive force was found as 2500 and 2130 Oe, respectively. Remanent magnetization was 35and 30 emu mol1forg- andε-MnO2, respectively.

A zinc coordination polymer derived from pyridine‐2,6‐dicarboxylate (PDC), {[Zn2(PDC)2]}n, was successfully prepared via conventional, sonication and microwave‐irradiation methods. The composition and characteristics of the obtained coordination polymers (CPs) were investigated by elemental analysis, TGA/DTA, X‐ray diffraction and spectroscopic techniques. The so obtained CPs were heat‐treated in the air at 600 °C for 2 h to produce ZnO of nanosized particles (NPs). It is of interest to note that the synthesis approach of the precursor greatly affects both the nanoparticle size and the structure of the resulting ZnO NPs. Moreover, the smallest particle size was associated with the sample derived from the ultrasonically prepared precursor. TEM analysis revealed that all samples have sphere‐like morphologies. Structural analysis of the prepared ZnO samples was conducted and compared using Rietveld analysis of their PXRD patterns. Optical band gap calculations based on analysis of the UV–vis spectra of ZnO samples using Tauc's power law were achieved. The highest band gap of 3.63 eV was observed for ZnO sample obtained from the ultrasonically prepared precursor. Furthermore, the photocatalytic activity of ZnO NPs for the removal of Eosin Y color was monitored. The highest removal efficiency was recorded for ZnO originated from the ultrasonically synthesized precursor. Enhancement of removal efficiency that reached 98% was attained in only a period of 8 min. Its recycling test showed that it can be reused without structural changes over four cycling experiments.

A zinc coordination polymer derived from pyridine‐2,6‐dicarboxylate (PDC), {[Zn2(PDC)2]}n, was successfully prepared via conventional, sonication and microwave‐irradiation methods. The composition and characteristics of the obtained coordination polymers (CPs) were investigated by elemental analysis, TGA/DTA, X‐ray diffraction and spectroscopic techniques. The so obtained CPs were heat‐treated in the air at 600 °C for 2 h to produce ZnO of nanosized particles (NPs). It is of interest to note that the synthesis approach of the precursor greatly affects both the nanoparticle size and the structure of the resulting ZnO NPs. Moreover, the smallest particle size was associated with the sample derived from the ultrasonically prepared precursor. TEM analysis revealed that all samples have sphere‐like morphologies. Structural analysis of the prepared ZnO samples was conducted and compared using Rietveld analysis of their PXRD patterns. Optical band gap calculations based on analysis of the UV–vis spectra of ZnO samples using Tauc's power law were achieved. The highest band gap of 3.63 eV was observed for ZnO sample obtained from the ultrasonically prepared precursor. Furthermore, the photocatalytic activity of ZnO NPs for the removal of Eosin Y color was monitored. The highest removal efficiency was recorded for ZnO originated from the ultrasonically synthesized precursor. Enhancement of removal efficiency that reached 98% was attained in only a period of 8 min. Its recycling test showed that it can be reused without structural changes over four cycling experiments.

A zinc coordination polymer derived from pyridine‐2,6‐dicarboxylate (PDC), {[Zn2(PDC)2]}n, was successfully prepared via conventional, sonication and microwave‐irradiation methods. The composition and characteristics of the obtained coordination polymers (CPs) were investigated by elemental analysis, TGA/DTA, X‐ray diffraction and spectroscopic techniques. The so obtained CPs were heat‐treated in the air at 600 °C for 2 h to produce ZnO of nanosized particles (NPs). It is of interest to note that the synthesis approach of the precursor greatly affects both the nanoparticle size and the structure of the resulting ZnO NPs. Moreover, the smallest particle size was associated with the sample derived from the ultrasonically prepared precursor. TEM analysis revealed that all samples have sphere‐like morphologies. Structural analysis of the prepared ZnO samples was conducted and compared using Rietveld analysis of their PXRD patterns. Optical band gap calculations based on analysis of the UV–vis spectra of ZnO samples using Tauc's power law were achieved. The highest band gap of 3.63 eV was observed for ZnO sample obtained from the ultrasonically prepared precursor. Furthermore, the photocatalytic activity of ZnO NPs for the removal of Eosin Y color was monitored. The highest removal efficiency was recorded for ZnO originated from the ultrasonically synthesized precursor. Enhancement of removal efficiency that reached 98% was attained in only a period of 8 min. Its recycling test showed that it can be reused without structural changes over four cycling experiments.

A zinc coordination polymer derived from pyridine‐2,6‐dicarboxylate (PDC), {[Zn2(PDC)2]}n, was successfully prepared via conventional, sonication and microwave‐irradiation methods. The composition and characteristics of the obtained coordination polymers (CPs) were investigated by elemental analysis, TGA/DTA, X‐ray diffraction and spectroscopic techniques. The so obtained CPs were heat‐treated in the air at 600 °C for 2 h to produce ZnO of nanosized particles (NPs). It is of interest to note that the synthesis approach of the precursor greatly affects both the nanoparticle size and the structure of the resulting ZnO NPs. Moreover, the smallest particle size was associated with the sample derived from the ultrasonically prepared precursor. TEM analysis revealed that all samples have sphere‐like morphologies. Structural analysis of the prepared ZnO samples was conducted and compared using Rietveld analysis of their PXRD patterns. Optical band gap calculations based on analysis of the UV–vis spectra of ZnO samples using Tauc's power law were achieved. The highest band gap of 3.63 eV was observed for ZnO sample obtained from the ultrasonically prepared precursor. Furthermore, the photocatalytic activity of ZnO NPs for the removal of Eosin Y color was monitored. The highest removal efficiency was recorded for ZnO originated from the ultrasonically synthesized precursor. Enhancement of removal efficiency that reached 98% was attained in only a period of 8 min. Its recycling test showed that it can be reused without structural changes over four cycling experiments.

Finite element simulation for MHD ferro-convective flow in an inclined double-lid driven L-shaped enclosure with heated corners.

MHD natural convection from two heating modes in fined triangular enclosures filled with porous media using nanofluids. .