Infrared absorption spectra of the precipitated solids separated from aluminiumhydroxide solutions below the pH of minimum solubility of AI(OH)3 demonstrate the slow ageing of polymeric A1 complexes to gibbsite. On comparison with the spectra of natural gibbsites, shifts in absorption frequency during crystal growth are interpreted in terms of changes in hydrogen bonding as a consequence of dep...

This paper examines the compressive strength of sodium silicate bonded cores for aluminum casting with different additives. Various materials are used as additives among which it is found that 5% sand size bauxite has the best effect on both gas strength and de-coring 98.5% silica content sand with 70-90 AFS No. with 4% sodium silicate is used. The results indicate that although very good colla...

OBJECTIVES The main objective is the characterization of the setting reaction in glass ionomer cements (GICs) based on experimental glasses using the (27)Al magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy in order to understand the crosslinking process during the setting reaction. METHODS Three types of GICs which are based on fluoro-alumino-silicate glasses (LG125, ART...

The fouling of a spiral wound reverse osmosis (RO) membrane after nearly 1 year of service in a brackish water treatment plant was investigated using optical and electron microscopic methods, Fourier transform infrared spectroscopy (FTIR) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Both the top surface and the cross-section of the fouled membrane were analysed to moni...