the major foible of dental ceramics is their brittle nature. therefore, the producers of these materials have focused on the “strength” issue. a method of increasing strength is ion exchange on porcelain surface which leads to formation of a compressive crust that opposing forces should overcome before developing a crack. in current study, ion exchange in two types of porcelain, ceramco ii whic...

this study deals with bioleaching of the low grade uranium ore of saghand mine in iran using a mixed culture of mesophilic bacteria (acidithiobacillus ferrooxidans, acidithiobacillus thiooxidans and leptospirillum ferrooxidans). experiments were carried out in shaking flask examining the effect of temperature, initial ferrous ion concentration, pulp density and particle size. variations of ph, ...

an extraction-spectrophotometric method for the determination of trace amounts of ammonium ion is described. ammonium ion is effectively extracted as a neutral ternary complex nh . db 18c6. calmagite at ph 3.0 into chloroform, followed by spectrophotometric determination at =48 5 nm. molar absorptivity of the ternary complex at this wavelength is 1.08 10 mol cm . beer's law is obeyed over ...

This study was conducted to investigate organoclay prepared using montmorillonite clay with zinc oxide (ZnO) nanoparticles and a long-chain organic surfactant hexadecyltrimethylammonium bromide for the removal of nitrate ion from aqueous solutions. Adsorbents were evaluated by X-Ray Diffraction (XRD), Fourier Transform Infra-Red (FT-IR),...

A conductance study of the interaction between Cs+, Rb+, NH4+, K+, T1+ and Ag+ ions and18-crown-6 (18C6), benzo-18-crown-6 (B18C6), dicyclohexyl-18-crown-6 (DC18C6),dicyclohexyl-24-crown-8 (DC24C8), dibenzo-24-crown-8 (DB24C8) in different binarymixtures of acetonitrile (AN) with dimethylsulfoxide (DMSO) and dimethylformamide (DMF)at 25 °C has been carried out. Formation constants of the result...