Stabilization of Dicalcium Silicate-Zn Composite Approaching Layered Double Hydroxide Structure for Bioactive Cement Applications

Layered Double Hydroxide (LDH) is ionic clay that is characterized by the union of metal cations and OH- hydroxides. LDH composites exhibit considerably high releasing and recharging capacity and have applications as bioactive cements. They can be prepared by direct co-precipitation of metal salts at controlled pH. The preparation is carried out from an acid solution of Zn (NO3)2.6H2O, Al (NO3)3.9H2O and a basic solution of Na2CO3 and NaOH, with a Zn/Al ratio = 3, the pH is stabilized between 9 and 9.5 at a constant temperature of 45°C. The objective of this study is to incorporate Zinc and Aluminum elements at different percentages in dicalcium silicate phase to produce C2S phase incorporating LDH composite. The characterizations of the developed phases by XRD and SEM indicate the formation of stoichiometric LDH phases Zn6Al2(OH)16CO3.4H2O and non-stoichiometric Zn0.61Al0.39 (OH)2(CO3)0.195.xH2O, the incorporation of Zn in the belitic C2S phase and not Al. The obtained micrographs by SEM(EDAX) analysis show new morphology of the stabilized composite.

Comparative LM, SEM and EDAX study of chalk glands on leaf and stem of two species of Plumbago Linn.

Stem and leaves of two species of PlumbagoLinn.viz. P. zeylanica Linn.andP. auriculata Lam. were investigated for the structure and chemical composition of chalk glands. Light Microscopy (LM) and Scanning Electron Microscopy (SEM) revealed the presence of chalk glands on both lower as well as upper surface of leaf and stem of both species. Chalk glands are abundant on lower surface and sparse on upper surface of leaf. Chalk glands are approximately hemispherical glands with oval or almost circular outline. It is composed of 8 cells arranged in two circles – central circle of 4 secretory cells and outer circle of 4 adjoining cells. Each secretory cell has depression which corresponds to pore. Each gland is surrounded by 4 subsidiary cells. No significant difference in the structure of chalk glands in both species was noticed. Chalk glands occupy three different positions with regard to epidermal cells –at the same level of the epidermis, slightly sunken in the epidermis and slightly raised above the epidermis. Common elements found in EDAX analysis of all chalk glands are carbon, oxygen, magnesium, sulphur, potassium and calcium. Differences in the presence of elements silicon, chlorine, aluminium, sodium, phosphorus were observed. The presence of significant amount of calcium in chalk glands and their dried deposits and absence of sodium and chlorine from dried deposits and even in some chalk glands appealed to use the term ‘Chalk gland’ instead of ‘Salt gland’ in Plumbago.

Crystal Chemistry, Rietveld Analysis, Structural and Electrical Properties of Cobalt-Erbium Nano-Ferrites

Synthesis of Cobalt-Erbium nano-ferrites with formulation CoErxFe2-xO4 (x = 0, 0.005, 0.010, 0.015, 0.020, 0.025, and 0.030) using technique of citrate-gel auto-combustion was done. Characterization of prepared powders was done by using XRD, EDAX, FESEM, AFM and FTIR Spectroscopy, DC resistivity properties respectively. XRD Rietveld Analysis, SEM, TEM and EDAX analysis were taken up in studying spectral, structural, magnetic and electrical properties. XRD pattern of CEF nano particles confirm single phase cubic spinal structure. The structural variables given by lattice constant (a), lattice volume (v), average crystallite size (D) and X-ray density(dx), Bulk density (d), porosity (p), percentage of pore space (P%), surface area (s), strain (ε), dislocation density (δ), along with ionic radii, bond length and hoping length were calculated. SEM and TEM results reveal homogeneous nature of particles accompanied by clusters having no impurity pickup. TEM analysis gives information about particle size of nanocrystalline ferrite while EDAX analysis confirm elemental composition. Emergence of two arch shaped frequency bands (ν1 and ν2) that represent vibrations at tetrahedral site (A) and octahedral site(B) was indicated by spectra of FTIR. The samples electrical resistivity (DC) was measured between 30°C -600°C with Two probe method. XRD Rietveld analysis confirm crystallite size lying between 20.84 nm–14.40 nm while SEM analysis indicate formation of agglomerates and TEM analysis indicate particle size ranging between 24 nm–16 nm. DC Electrical measurements indicate continuous decrease in resistivity with increasing temperature while increasing doping decreases curie temperature. The Magnetic parameters such as Saturation magnetization (Ms), Remanent magnetization (Mr), Coercivity (Hc) and Squareness ratio (R = Mr/Ms), Magnetic moment (nB) were altered by doping of Er+3 content in the increasing order (x = 0.00 to 0.030). The increasing erbium content decreases magnetization thus converting the sample into soft magnetic material. Observations indicated strong dependence of magnetic properties on Erbium substitution and coercivity varies in accordance with anisotropy constant. Due to the presence of magnetic dipole Erbium substituted cobalt ferrites can be used in electromagnetic applications. The present study investigates the effect of different compositions of Er3+ replaced for Fe on structural properties and electrical resistivity of cobalt ferrites.

Influence of Bio-Inspired Ag doped MoO3 Nanoparticles in the Seedling Growth and Inhibitory Action Against Microbial Organisms

Herein we report the hydrothermal synthesis, characterization and biological applications of h-MoO3 and silver doped MoO3 nanoparticles (NPs). The phase formation of the synthesized NPs was identified using X-ray diffraction studies and vibrational spectral studies. The average crystallite size of the NPs tends to decrease as the dopant concentration increases. The surface morphology and the elemental composition of the nanoparticles were observed from SEM and EDAX analysis. The crystallite nature was obtained from HRTEM images. The band gap energies obtained from UV-DRS spectra for h-MoO3 (3.26 eV) were starting to decrease as the concentration of the dopant Ag increases (3.22-2.76eV). The antibacterial activity of the prepared nanoparticles was tested against some gram positive and gram negative bacterial strains viz., Staphylococcus aureus, Bacillus cereus and Citrobacter koseri and Pseudomonas aeruginosa respectively. Also their seed germination properties were studied on foxtail and finger millet seeds for a period of seven days.

Eco-Friendly Synthesis, TEM and Magnetic Properties of Co-Er Nano-Ferrites

Synthesis of Cobalt-Erbium nano-ferrites with formulation CoErxFe2-xO4 (x = 0, 0.005, 0.010, 0.015, 0.020, 0.025, and 0.030) using technique of citrate-gel auto-combustion was done. Characterization of prepared powders was done using XRD, EDAX, FESEM, TEM, AFM, and FTIR spectroscopy, VSM: magnetic properties, respectively. XRD Rietveld Analysis, SEM, TEM, and EDAX analysis studied spectral, structural, and magnetic properties. XRD pattern of CEF nanoparticles confirms single-phase cubic spinal structure. The structural variables are given by lattice constant (a), lattice volume (v), the average crystallite size (D) and X-ray density (dx), bulk density (d), porosity (p), percentage of pore space (P%), surface area (s), strain(ε), dislocation density (δ), along with ionic radii, bond length and hoping length were calculated. SEM and TEM results reveal the homogeneous nature of particles accompanied by clusters having no impurity pickup. TEM analysis gives information about the particle size of nanocrystalline ferrite, while EDAX analysis confirms elemental composition. The emergence of two arch-shaped frequency bands (ν_1 and〖 ν〗_2) that represent vibrations at the tetrahedral site (A) and octahedral site(B) was indicated by spectra of FTIR. The XRD Rietveld analysis confirms crystallite size lying between 20.84 nm-14.40 nm, while SEM analysis indicates the formation of agglomerates and TEM analysis indicates particle size ranging between 24nm-16 nm. The XRD Rietveld analysis confirms crystallite size lying between 20.84nm-14.40nm, while SEM analysis indicates the formation of agglomerates and TEM analysis indicates particle size ranging between 24 nm - 16 nm. The magnetization measurements indicated that increasing Er3+ content in cobalt ferrites decreases magnetization from 60emu/g to 42emu/g while coercivity decreases (18990) as compared to CoFe2O4 (18998) in cobalt ferrites with doping. The present study investigates the effect of different compositions of Er3+ replaced for Fe on structural and magnetic properties of cobalt ferrites.

Excellent Fire Retardant Properties of CNF/VMT Based LBL Coatings Deposited on Polypropylene and Wood-Ply

In this report, layer by layer (LBL) fire retardant coatings were produced on wood ply and Polypropylene Homopolymer/Flax fiber composites. FE-SEM and EDAX analysis was carried out to analyze the surface morphology, thickness, growth rate and elemental composition of the samples. Coatings with a high degree of uniformity were formed on Polypropylene composite (PP/flax), while coatings with highest thickness were obtained on wood ply (wood). FTIR and Raman spectroscopy were further used for the molecular identifications of the coatings, which confirmed the maximum deposition of the solution components on the wood substrate. A physiochemical analysis and model was proposed to explain the forces of adhesion between the substrate and solution molecules. Fire protection and thermal properties were studied using TGA and UL-94 tests. It was explored, that the degradation of the coated substrates was highly protected by the coatings as follows: wood > PP/flax > PP. From the UL-94 test, it was further discovered that more than 83% of the coated wood substrate was protected from burning, compared to the 0% of the uncoated substrate. The flammability resistance of the samples was ranked as wood > PP/flax > PP.

Safety and Efficacy of Pseudomonas Exopolymer in Sequestration of Iron From Aqueous Environments

The present study reports the iron binding characteristics and safety of an exopolymer (EBP) of an environmental isolate of Pseudomonas sp. The EBP was predominantly polysaccharide in composition with pyruvic and uronic acid residues. A prevalence of carboxyl and hydroxyl groups was observed in the Fourier-transform infrared spectroscopy (FTIR) results, while scanning electron microscopy (SEM) revealed a porous structure in a linear fashion with large number of grooves. The purified EBP was stable for over two months and exhibited rapid binding of iron (25mg/L) within 10 minutes at ambient temperature. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDAX) analysis of iron challenged EBP suggested the involvement of carboxyl groups in potentiating iron removal. Both Langmuir and Freundlich adsorption isotherms depicted high iron removal capacity in comparison to reported biomasses or biopolymers. Cytotoxic effects were not observed upon challenging various doses of EBP in RAW 264.7 cell lines implying a strong possibility of application of the EBP.

Construction of Modified CuO-Co3O4-ZnO Electrode for Acetone Detection in Breath

Acetone in breath can be used as a biomarker for noninvasive detection of diabetes. The acetone level in breath is substantially high for diabetic patients. In this study, mixed metal oxide nanocomposite of CuO-Co3O4 -ZnO was used for the electrochemical detection of acetone in artificial breath solution. The structural and morphological characterization of synthesized nanocomposite was done by XRD, RAMAN and SEM (EDAX) analysis. The electrochemical study was performed and the metal oxide modified electrode showed the sensitivity of 6.52 μA cm-2 ppm-1 towards the detection of acetone in the artificial solution.