S In this work, snail shells were used as a calcium source in synthesis of carbonated hydroxyapatite (CHAp) particles using a co-precipitation method. Then, the CHAp was further processed to produce a porous structure scaffold using a simple gas foaming method with H₂O₂ solution (30%) as foaming agent, followed by densification at high temperature. Ratio of liquid H₂O₂ solution/CHAp solid was varied from 0.75/1, 1/1, and 1.25/1 ml/g. A scanning electron microscope (SEM) was used to observe the morphology of samples. Chemical structure and compositions were analyzed by a Fourier transform infrared (FTIR) and an energy dispersive X-ray (EDX). Crystallographic and phase identity of samples were evaluated using an X-ray diffractometer (XRD). XRD, FTIR and EDX results showed the CHAp successfully produced from snail shells. SEM analysis on CHAp morphology indicated that CHAp has sphere-like grain with size under 1 μm. Higher ratio of liquid H₂O₂ solution/CHAp solid brings bigger and richer macro-pores structure in the scaffold, yet microporosity seems to independent to this parameter. High temperature treatment to densify the scaffold has no profound effect on purity of the final scaffold.

Microstructures with diverse and individualized morphologies are achieved by computer generated holography to reconfigure azopolymer micropillars in three dimensions.

This study aimed to investigate the effect of the amount of carbonate in synthesis to the crystallography properties of carbonated-hydroxyapatite (CHAp) using the snail shells as the calcium source. Snail shells were cleaned, milled, and sintered at 1000°C for 4 hours to get CaO powder. CHAp synthesized by co-precipitation method. The molar ratio CO₃ ^2-/PO₄ ^3- was varied 0/6, 2/6, 3/6, and 6/6. Meanwhile, the molar ratio of Ca/P was kept at 1.67. After synthesis, the solution was aged, centrifugally washed, dried, and sintered at 400°C for 2 h in the air atmosphere. A scanning electron microscope (SEM) was used to observe the morphology of CHAp. An energy dispersive spectroscopy (EDS) was used to determine the chemical composition of CHAp. An X-Ray Diffractometer (XRD) was conducted to analyze the crystallography of CHAp. Fourier transform infrared (FT-IR) was used to evaluate the chemical structure of the CHAp. The XRD spectra of CHAp of all variations show they have apatite phase. There is no secondary phase observed in XRD spectra. The results of FTIR and EDS supported the XRD results. The increasing of carbonate amount in synthesis decreased the crystallinity and crystallite size of CHAp. The lattice parameter a-axis was decreased, but the lattice parameter c-axis was increased as the amount of carbonate increased in the synthesis process. The increasing of carbonate amount in synthesis decreases the crystallite size of CHAp. The results demonstrate that the amount of carbonate in synthesis affects the crystallography properties of CHAp.

The measurement of the refractive index typically requires the use of optical ellipsometry which, although potentially very accurate, is extremely sensitive to the structural properties of the sample and its theoretical modeling, and typically requires specialized expertise to obtain reliable output data. Here, we propose a simple diffractive method for the measurement of the refractive index of homogenous solid thin films, which requires only the structuring of the surface of the material to be measured with the profile of a diffraction grating. The refractive index of an exemplary soft-moldable material is successfully estimated over a wide wavelength range by simply incorporating the measured topography and diffraction efficiency of the grating into a convenient scalar theory-based diffraction model. Without the need for specialized expertise and equipment, the method can serve as a simple and widely accessible optical characterization of materials useful in material science and photonics applications.

The aim of this work is to investigate the influence of sintering temperature on purity and crystallography properties of carbonated hydroxyapatite (CHAp). The CHAp was synthesized using a coprecipitation method. The snail shells (Pillaampulacea) were processed to yield calcium oxide as the calcium source in synthesis. The CHAp powder then was sintered for 2 h in an air atmosphere at 400, 600, 800, and 1000°C. An X-Ray diffractometer (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and energy dispersive x-ray (EDX) are used to investigate the physicochemical properties of CHAp. XRD, FTIR, and EDS results show primary phase is carbonated hydroxyapatite. Calcium oxide as a secondary phase is detected starting from 800°C. The crystallinity and crystallite size are increased along the increasing of sintering temperature. Drastic enhancement on these properties is shown at 600–800°C. However, there is no simple relation to the sintering temperature and lattice parameters. These results show that sintering temperature has an important role in the purity and crystallography properties of the CHAp.