B. Unni Nair

An improved product-process for cleaner chrome tanning in leather processing

Abstract Severe restrictions imposed by the pollution control authorities on the disposal of chromium, total dissolved solids and chlorides in tannery effluents have forced the tanners to look for low-waste, high exhaust chrome tanning salts. An improved chrome syntan with more than 90% uptake of chrome has been developed. The new product serves both as tanning and retanning agent and can be applied directly to delimed pelts thus eliminating the conventional pickling stage in the leather processing. This modified process helps to reduce the chemical oxygen demand (COD), total dissolved solids (TDS) and chlorides in the spent tan liquor by 51, 81 and 99%, respectively. The product offers full, soft leathers having shrinkage temperature comparable to conventional chrome tanned skins. Since the developed product is highly reactive, it saves time and reduces the water requirement when compared to the conventional chrome tanning method. Thus the novel product/process developed not only has advantages in reducing pollution loads but also seems to be techno-economically viable.

Quantification of reactive sites in DNA bases using condensed Fukui functions

Abstract The Fukui function values of various atoms in DNA bases have been computed with a view to understand their reactivity. Since reactivity of DNA bases depends on the surrounding solvent medium, the effect of incorporation of bulk solvent around the bases has also been studied using self consistent reaction field approach with in the frame work of Hartree–Fock theory.