Iranian Journal of Chemistry and Chemical Engineering
Volume:21 Issue: 2, Nov-Dec 2002

The polymer supported hypochlorite ion is a selective oxidizing agent for the oxidation of various alcohols to aldehydes and ketones. Similarly it successfully oxidizes various Hantzsch type 1,4 - dihydropyridines to corresponding pyridines

A new correlation function for the calculation of viscosity for five typical supercritical gases is presented using the Rainwater-Friend and modified Enskog theories. It is shown that by using accurate values for the thermal pressure and co-volume in the modified Enskog theory, this correlation function is suitable for calculation of the viscosity of supercritical gases, without any density and temperature limitation. For this purpose, two new correlation functions for the calculation of the thermal pressure coefficient and co-volume are presented. It is also shown that the co-volume in the modified Enskog theory depends not only on temperature, but also on density. The accuracy of the calculated viscosity is about 1%, which is much better than the previous work. It is also shown that the modified Enskog Theory can be extended to very high density-temperature ranges by choosing correct values for the thermal pressure and co-volume

A combined electrodeposition-ETAAS technique has been applied to the analysis of Pb, Cd, Co, Ni, Cr and Mn in biological samples in order to overcome interferences and to minimize sample pretreatment. It requires minimal sample preparation with the electrolysis process aiding partial decomposition of the organic matrix, adequate for the release and deposition of trace elements. In an initial electrodeposition step, the graphite furnace is coated by Pd. Analytes are then electrodeposited in situ from the sample at optimized applied voltage and time onto the Pd-coated furnace, followed by removal of spent electrolyte and atomization. The high background signals due to matrix components of urine and blood were eliminated by the technique and the sensitivity of determination was improved up to five-fold with respect to conventional ETAAS technique. A good precision of 1-3 %RSD (depending on the element and sample matrix) has been obtained. The recovery of added analytes is close to 100%, based on comparison with conventional ETAAS of aqueous samples. The accuracy of the technique was established by analyzing the urine standard reference material, SRM2670. The results of determinations of the elements tested are within the range of certified values given by the NIST with an acceptable %RSD.

Diagnosis of infected and affected dentine is an important Factor in clinical restorative treatment of dentine. In this study, the IR and Raman spectra of the sound dentine, infected dentine and affected dentine are reported. The structure of infected dentine and affected dentine has been compared with the sound dentine and hydroxyapatite. It is shown while the infected dentine has lost its structure, the affected dentine has more or less a structure similar to the sound dentine. The molecular structure of collagen remains unchanged in both infected and affected dentine.