Aninda Nafis Ahmed

Utilization of hard rock dust with red clay to produce roof tiles

Abstract Utilization of rock dust to produce roof tiles and its effects on properties of tiles, mixed with red clay collected from Naogaon district of Bangladesh were investigated. After proper characterization of the raw materials, tiles were prepared with different percentages of rock dust (10-50%) mixed with clay sintered from 850-1100 °C temperature. Rock dust has been found good for using as fluxing material after XRF study. The samples were tested for different properties such as water absorption, porosity, mechanical strength, linear shrinkage, and bulk density. The strength values have exceeded the minimum standard requirement for roof tiles with low water absorption in most samples. The results obtained made it possible to conclude about the possibility of producing roof tiles incorporating up to 40% of rock dust having better properties (lower water absorption 6.5%, strength value 31.97 MPa) fired at 900 °C. Therefore these dust acts as a fluxing agent and reducing the sinteringtemperature of the clay material.

Study on the Rietveld analysis for synthesized zinc oxide nanoparticles

In this work, ZnO nanoparticles were prepared by using ZnCl2 and NaOH as precursors using sol-gel chemical method. Synthesized ZnO was characterized by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Topas 4.2 software for Rietveld analysis. Formation of simonkolleite, Zn5(OH)8Cl2.H2O instead of ZnO nano particles was revealed from XRD studies. Formation of hexagonal zincite structure of the ZnO samples was also confirmed by XRD studies. From Rietveld analysis, rise of crystallite size was observed with increasing NaOH concentrations. Morphology and particle size of synthesized ZnO nanoparticles showed from FESEM studies 20-50 nm sized nano particles were evident from FESEM micrographs, which was found consistent with the crystallite size measured by Rietveld analysis of XRD studies. This particle has been applied in different industrial sectors such as solar cells, UV detectors, photodiodes etc.In this work, ZnO nanoparticles were prepared by using ZnCl2 and NaOH as precursors using sol-gel chemical method. Synthesized ZnO was characterized by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Topas 4.2 software for Rietveld analysis. Formation of simonkolleite, Zn5(OH)8Cl2.H2O instead of ZnO nano particles was revealed from XRD studies. Formation of hexagonal zincite structure of the ZnO samples was also confirmed by XRD studies. From Rietveld analysis, rise of crystallite size was observed with increasing NaOH concentrations. Morphology and particle size of synthesized ZnO nanoparticles showed from FESEM studies 20-50 nm sized nano particles were evident from FESEM micrographs, which was found consistent with the crystallite size measured by Rietveld analysis of XRD studies. This particle has been applied in different industrial sectors such as solar cells, UV detectors, photodiodes etc.

ZnO nanoparticles preparation from spent zinc–carbon dry cell batteries: studies on structural, morphological and optical properties

ABSTRACT Recovery and recycling of valuable materials from battery waste is challenging as well as important from economic and environmental point of view. In this work, spent zinc–carbon batteries were processed with HCl and NaOH to synthesize ZnO nanoparticles. ZnO nanopowders were also prepared by using ZnCl2 as precursors with varying amount of NaOH using sol–gel method. In both cases, ZnO nano particles were characterized with XRD, XRF, FESEM, EDAX, particle size analyzer and UV–visible (UV–Vis) spectroscopy. The purity of the synthesized ZnO from spent zinc–carbon batteries was found to be 99.69%. FESEM micrographs showed the reduction in particle size from 50 nm to 20 nm with a decrease in NaOH concentration. UV–Vis study showed significant peak shift with maximum absorption between 365 nm and 359 nm region of the visible spectrum. Because of these remarkable properties, as prepared ZnO nanoparticles can find applications in biomedicine, nanoelectronic devices, sensors, nanomedicine, GATE dielectrics, photovoltaic devices, etc.

Effect of Sintering Temperature on (Bi2O3Fe2O3)0.8(Nb2O5)0.2

(Bi2O3Fe2O3)0.8(Nb2O5)0.2 was synthesized by solid state reaction method. (Bi2O3Fe2O3)0.8(Nb2O5)0.2 was made for the investigation of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Dielectric property. XRD pattern reveals that three phases were obtained with Bismuth Iron Niobium Oxide. SEM elicits that grain size increases with the enhancement of sintering temperature. Dielectric property decreases with the augmentation of frequency.

Effect of sintering temperature on structural and dielectric properties of (Bi 2 O 3 Fe 2 O 3 ) 0.4 (Nb 2 O 5 Nd 2 O 3 ) 0.6

(Bi<inf>2</inf>O<inf>3</inf>Fe<inf>2</inf>O<inf>3</inf>)<inf>0.4</inf>(Nb<inf>2</inf>O<inf>5</inf>Nd<inf>2</inf>O<inf>3</inf>)<inf>0.6</inf> was syhthesised by solid state reaction method for studying the properties of the material. Synthesized material was sintered at two different temperature (1000°C and 1150°C). X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Dielectric property and DC resistivity of the materials are reported in this paper. Existance of bismuth iron niobium oxide and neodymium iron(lll) oxide phases were confirmed by XRD. SEM image yielded that the size of grain increases with the increase of sintering temperature. Low dielectric constant and loss tangent were observed from dielectric property. Insulating nature of the material was found by DC resistivity analysis.

Microstructure evolution and electrical characterization of Lanthanum doped Barium Titanate (BaTiO3) ceramics

In the current work, we investigated the structural and dielectric properties of Lanthanum oxide (La2O3) doped Barium Titanate (BaTiO3) ceramics and established a correlation between them. Solid state sintering method was used to dope BaTiO3 with 0.3, 0.5 and 0.7 mole% La2O3 under different sintering parameters. The raw materials used were La2O3 nano powder of ~80nm grain size and 99.995% purity and BaTiO3 nano powder of 100nm grain size and 99.99% purity. Grain size distribution and morphology of fracture surface of sintered pellets were examined by Field Emission Scanning Electron Microscope and X-Ray Diffraction analysis was conducted to confirm the formation of desired crystal structure. The research result reveal that grain size and electrical properties of BaTiO3 ceramic significantly enhanced for small amount of doping (up to 0.5 mole% La2O3) and then decreased with increasing doping concentration. Desired grain growth (0.80-1.3 µm) and high densification (<90% theoretical density) were found by pr...