Ultrasonic-assisted conversion of limestone into needle-like hydroxyapatite nanoparticles.

Needle-like hydroxyapatite nanoparticles were successfully synthesized via a reaction between calcium oxide (CaO) that was obtained from calcined limestone and orthophosphoric acid (HPO) under ultrasonic irradiation at 25 °C. The reaction systems were exposed to ultrasonic waves of 20 kHz for various times ranging from 0 to 4 h. The initial and final pH values of the mixtures of CaO and HPO solution were continuously observed (pH < 4.

Synthesis and characterization of high purity hydroxyapatite nanorods by hydrothermal technique.

High purity hydroxyapatite (HAp) nanorods were synthesized by hydrothermal technique using Ca(NO3)2 x 4H2O and (NH4)2HPO4 as starting materials in a hydrothermal reactor at 150-200 degrees C for 12-24 h with pH6 and pH9.5, respectively. The prepared HAp nanorods were characterized by XRD, FTIR, and TEM techniques.

Nanofibers of barium strontium titanate (BST) by sol-gel processing and electrospinning.

This paper describes the fabrication of barium strontium titanate (Ba0.6Sr0.4TiO3 or BST) nanofibers by electrospinning method using a solution that contained poly(vinylpyrrolidone) and a sol-gel solution of BST.