Using Fly Ash Wastes for the Development of New Building Materials with Improved Compressive Strength

Fly ash wastes (silica, aluminum and iron-rich materials) could be smartly valorized by their incorporation in concrete formulation, partly replacing the cement. The necessary binding properties can be accomplished by a simple procedure: an alkali activation process, involving partial hydrolysis, followed by gel formation and polycondensation. The correlations between the experimental fly ash processing conditions, particle characteristics (size and morphology) and the compressive strength values of the concrete prepared using this material were investigated by performing a parametric optimization study to deduce the optimal processing set of conditions. The alkali activation procedure included the variation of the NaOH solutions concentration (8–12 M), temperature values (25–65 °C) and the liquid/solid ratio (1–3). The activation led to important modifications of the crystallography of the samples (shown by powder XRD analysis), their morphologies (seen by SEM), particle size distribution and Blaine surface values. The values of the compressive strength of concrete prepared using fly ash derivatives were between 16.8–22.6 MPa. Thus, the processed fly ash qualifies as a proper potential building material, solving disposal-associated problems, as well as saving significant amounts of cement consumed in concrete formulation.

Silver-calcium-borates as better replacement for conventional organic antimicrobials in cosmetic products

Microbes generally develop resistance towards organic antibacterial agents like ampicillin, Sulfonamides, methicillin, etc., and progressively new drugs are being invented to replace them. Hence, replacement of organic antibacterial agents with inorganic analogues requires constant research and the present investigation reports alternatives for conventional antimicrobial agents like methylparaben, diazolidinyl urea, etc., in the cosmetic products with silver incorporated calcium borates. The chemically synthesized silver-calcium borates have been analyzed for phase purity using powder XRD analysis, nature of bonding using FTIR vibrations, and morphology using SEM. The antibacterial and antifungal studies were carried out for the novel inorganic silver-calcium borates incorporated cosmetic products. The products were also subjected to thermal & photostability studies and found to be comparable with that of commercially available products. A minimum quantity of 3 ppm of silver-calcium borate concentration was required to bring about nearly 100% bacterial reduction in the cosmetic products.

Electrochemically Crafted Monodispersed γ-Cu5Zn8 Bimetallic Nanoalloy: Characterization and Its Synergistic Effect on Photocatalysis and Antibacterial Efficacy

The present work reports the investigation of monodispersed nano brass prepared by the facile electrochemical technique. The influence of reaction conditions on the surface morphology and size of the bimetallic nano alloy were investigated through high resolution scanning electron microscopy (HR-SEM) and powder X-ray diffraction (PXRD) technique. From the powder XRD analysis the nano alloy was identified as a [[EQUATION]] phase. The detailed investigation was carried out using transition electron microscope (TEM) for the textural features and γ-CuZn phase stoichiometry was revealed by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDAX) analyses. Optical responses were analysed using diffuse reflectance spectroscopy (DRS). The energy band gap obtained from the optical spectrum revealed it can be a good catalyst. Rate of photocatalytic reaction and mechanism of degradation were discussed in detail. Most importantly, electrodeposited γ-CuZn nano alloy reveals superior nano-catalytic activity on methyl orange dye degradation in the shorter irradiation time. Furthermore, the antimicrobial efficacy of the γ-CuZn nano alloy was examined using gram positive and gram negative bacterial strains.

ROLE OF ANNEALING TEMPERATURE ON THE STRUCTURAL, MORPHOLOGICAL AND OPTICAL CHARACTERIZATIONS OF SnO2 THIN FILMS SYNTHESIZED BY SPIN-COATING METHOD

The inuence of annealing temperature on the structural, morphological, and optical properties of SnO thin lms 2 prepared by spin-coating method has been studied. The samples were thermally annealed at 673 K and 773 K for 2 hrs. Powder XRD analysis of the thin lms annealed at 673 and 773 K shows less intense and broad diffraction peaks. The size of the grains found to increase with annealing temperature. The grain size of the synthesized lm is enhanced due to increasing annealing temperature upto 773 K. The grains are well agglomerated for lms annealed at the higher temperature of 773 K. The transmission spectra of SnO thin lms annealed at the 2 temperatures of 673 and 773 K was analyzed. The percentage of transmittance found to increase from 56 to 91% with an increase in the annealing temperature from room temperature to 773 K. The bandgap energy value (Eg) was calculated and it increases from 3.25 to 3.35 eV with the increase in annealing temperatures.

Hydrogen Peroxide-Assisted Hydrothermal Synthesis of BiFeO3 Microspheres and Their Dielectric Behavior

Despite considerable efforts undertaken in a rapidly developing area of multiferroic research, synthesis of phase pure BiFeO3 is still a matter of intensive research. In this work, we report the shape-controlled synthesis of pure BiFeO3 microspheres via a facile hydrothermal route. The prepared BiFeO3 powder has been characterized using powder X-ray Diffraction (XRD), Differential Thermal analysis (DTA), Scanning Electron microscopy (SEM), and impedance spectroscopy. Powder XRD analysis confirms the formation of pure rhombohedrally distorted perovskite with R3c space group. Scanning electron micrograph revealed that the prepared BiFeO3 microspheres are nearly spherical in shape with uniform size distribution. The BiFeO3 microspheres exhibit a dielectric constant value of ~110 at 1000 KHz, which is higher than the BiFeO3 prepared by conventional solid-state reaction and sol–gel method. Variation of dielectric constant with temperature at different frequencies shows that the BiFeO3 has a dielectric anomaly of ferroelectric to paraelectric type at 1093 K and this phenomenon is well supported by TGA results.

Preparation and Powder XRD Analysis of Tris(2,2’-bipyridine)nickel(II) Trifluoroacetate

The complex containing Ni(II)-2,2’-bipyridin (bipy)-trifluoroacetate (TFA) was prepared by direct interaction of the corresponding precursors in an aqueous solution. AAS measurement for metal content, TGA-DTA analysis and electrical conductance suggest the ionic complex of [Ni(bipy)3](CF3COO)2·6H2O. The magnetic moment of 3.13–3.17 BM indicates the paramagnetism corresponding to two unpaired electrons which is clearly higher than that of the spin only value (2.87 BM), and commonly observed due to the spin-orbit coupling in Ni(II). UV-Vis spectral property revealed the first two main ligand field bands centered at about 14200 and 18650 cm–1, which are attributed to the spin-allowed transition, 3A2g→3T2g and 3A2g→3T1g(F), respectively. The expected third band at higher energy seems to appear as a shoulder at 26500 cm–1 (378 nm), as it is masked by a strong intensity of charge transfer band centered at 31050 cm–1. The infrared spectrum exhibits mode of vibrations of the functional groups of ligand and TFA. The powder diffractogram was refined by Le Bail method and found fit as monoclinic system of space group of P21/M, with figures of merit: Rp = 3.62, Rwp = 5.76, Rexp = 3.48, goodness of fitting (GOF) 2.745 and the derived Bragg R-Factor = 0.05.

Analysis of Structural, Morphological and Electrochemical on Ni (OH)2 Coated Carbon Sphere by Hydrothermal Method

Nickel hydroxide Ni (OH)2 nanoparticles (Nps) effectively embedded on carbon sphere (Ni(OH)2@CS) by facile hydrothermal method. The prepared sample was characterized through powder XRD analysis which clearly shows the crystalline structure of the Ni(OH)2@CS. FTIR spectra gave the functional group in the carbon sphere Ni(OH)2@CS Ni-O, C-O, C-C, C=C, and OH vibration on the Ni(OH)2@CS. The scanning electron microscope (SEM) shows the surface morphology of the sample. Energy dispersive analysis shows the elemental conformation of the prepared sample. The electrochemical performance analysis shows the Galvanostatic charge-discharge, cyclic voltammetry analysis gives the specific capacitance of the prepared sample. The impedance analysis shows the electrode-electrolyte interface on the electrode material.

Complex of Tris(Phenanthroline)Cobalt(II)Trifluoroacetate: Characterisation and Powder XRD Analysis

The powder complex of tris(phenanthroline)cobalt(II) trifluoroacetate (TFA) has been prepared by interaction of cobalt(II) nitrate, phenanthroline (phen) in aqueous solution with drops of ethanol, and an excess of saturated aqueous solution of sodium trifluoroacetate, whereupon the yellowish powder was produced. AAS measurment for the metal content, equivalent conductance (1:2), and TGA-DTA of the powder suggest the corresponding formula of [Co(phen)3](TFA)2.5H2O. The efffective magnetic moment of 4.9 BM indicates the high-spin nature of this complex which corresponds to three unpaired electrons in the electronic configuration of Co(II) with significantly higher than the spin only value due to the orbital contribution. UV-Vis spectrum of the complex reveals the d-d spin-allowed transition bands as well as the MLCT and intraligand band. The estimating transition energy ratio of 2.04 for ν2/ν1, is clearly in the range for octahedral configuration. The infrared spectral property indicates the main mode of vibrations for the functional groups of ligand phen and TFA, and thus supports strongly the formula proposed for this complex. The corresponding powder XRD was then refined using Rietica-Le Bail method and found to be fit as triclinic crystal system with space group of PĪ.

Growth, electrical, thermal, mechanical and etching studies on 4-chloroanilinium hydrogen (2R, 3R)-tartrate monohydrate-an organic NLO single crystal

An organic single crystal of 4-chloroanilinium hydrogen (2R,3R)-tartrate monohydrate (4CAHT) was grown by slow evaporation solution growth technique at room temperature. Single crystal XRD study confirmed that the crystal belongs to monoclinic system with the space group P21. Powder XRD analysis confirmed the crystalline nature of the compound. The presence of various functional groups in the compound was revealed by FT-IR analysis. UV studies showed the absence of absorption in the entire visible region. To determine the thermal stability of the grown crystals it was subjected to thermogravimetric and differential thermal analyses. Microhardness and etching studies were also carried out for the crystal. The powder second harmonic generation efficiency of 4CAHT was tested by Kurtz and Perry powder technique and the relative SHG efficiency of 4CAHT was found to be 1.44 times greater than that of standard KDP.

Structural, spectral, electrical, Z-scan and HOMO LUMO studies on new 2-amino-6-methylpyridinium 2-hydroxybenzoate crystal

New organic single crystals of 2-amino-6-methylpyridinium 2-hydroxybenzoate (2A6M2H) were grown by slow evaporation solution growth technique at room temperature. The grown crystal structure was studied using single crystal XRD. Crystalline nature and phases were confirmed by powder XRD analysis. FT-IR study was used to identify the functional groups present in the compound. UV-Vis study revealed that the lower cut off wavelength of the crystal is at 350 nm. The dielectric studies indicated the low value of dielectric loss at high frequency. Mechanical properties of the crystals were studied using Vickers microhardness test. The Z-Scan studies were conducted for the crystal using He–Ne laser.