The effect of DTPA on calcium carbonate scale deposition on copper and aluminium surfaces.

Calcium carbonate (CaCO3) scale inhibition by Diethylenetriaminepentaacetic acid (DTPA) on copper and aluminium metal surfaces was studied at 60 and 100 °C. The samples were characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results revealed a novel pot like morphology for calcite which was resulted from the transformation of dumbbell morphology. The pot like morphology exposed the possibility of hollow structures for other polymorphs and is resulted from the breaking apart of the dumbbell structures at the middle, followed by fluffing of the separated parts.

Excimer formation in inclusion complexes of ß-cyclodextrin with salbutamol, sotalol and atenolol: spectral and molecular modeling studies.

The inclusion complexation behavior of salbutamol, sotalol and atenolol drugs with ß-cyclodextrin (ß-CD) were investigated by UV-visible, fluorometry, time resolved fluorescence, FT-IR, (1)H NMR, SEM and PM3 methods. The above drugs gave a single emission maximum in water where as dual emission in ß-CD. In ß-CD solutions the shorter wavelength fluorescence intensity was regularly decreased and longer wavelength fluorescence intensity increased. Addition of ß-CD to aqueous solutions of drugs resulted into excimer emission. The excimer emission is concluded to be due to a 1:2 inclusion complex between ß-CD and drug. Nanosecond time-resolved studies indicated that all drugs exhibited biexponential decay in solvents and triexponential decay in CD. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.