Informatics Publishing Limited

S. K. Saha ¹, R. C. Srivastava ¹

Affiliations
1 Chemistry Group, Birla Institute of Technology and Science, Pilani 333031, Rajasthan, IN

Abstract

The field of biosensors is becoming increasingly high tech. This advancement is definitely welcome. But the cost factor is increasingly prohibitive in the underdeveloped and developing countries. Intelligent improvisations for the development of low cost indigenous ( Swadeshi ) science/technology hold the key to the advancement of science/technology in such countries. With this motivation we have developed in our laboratory improvised sensors for urea [1], cholesterol [2] and a simple method for the estimation of insulin [3]. In this article a concise account of these efforts is given. Very recently, we have also attempted to develop a taste sensor [4], the analysis of which utilizes the methods of non-linear science as against the analysis used in the present three sensors.

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S. K. Saha ¹, R. N. Choudhury ¹, S. K. Chakravarti ¹

Affiliations
1 Department of Chemistry, University of North Bengal, Derjeeling, IN

Abstract

Multiple equilibria in humic acid-Cu(II) and humic acid-Ca systems in 0.1 N KNO₃, have been studied at different pH's using ion selective electrodes. At pH 4.8, Ca has been found to form only MA⁺, where as Cu(II) forms both MA⁺ and MA₂, complexes. Significant negative co-operative effect has been observed in all the systems studied, which is more prominent in Ca-humic acid complex at low pH. Logarithms of intrinsic stability constant, K₀, ranged from 7.5 to 8.5 for Cu(II) and 5.8 to 6.0 for Ca-complexes. Results are compared with those for the two synthetic model humic acid-metal systems.

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P. K. Guha ¹, S. K. Saha ²

Affiliations
1 Department of Chemistry, Siliguri College, Siliguri, Dist Darjeeling-734401, W. Bangal, IN
2 Department of Chemistry, University of North Bengal, Darjeeling 734 430, W. Bengal, IN

Abstract

The properties of aqueous solutions of CTAB and TX-100 have been investigated in the presence of additives, viz., 1- and 2-naphthols by viscosity measurements. Unlike binary systems, relative viscosity versus concentration plots show well defined break points near cmc's in the presence of additives. Addition of 1-naphthol decreases the cmc values of both the surfactants while 2- naphthol decreases the cmc of TX-100 but increases that of CTAB slightly. The threshold additive concentration for gel formation (tac) by 1- and 2-naphthols are 3.2 mmol/lit and 2.4 mmol/lit respectively for CTAB whereas, they are 1.0 mmol/lit and 0.6 mmol/lit respectively for TX-100. The surfactant concentrations are, however, much below that of the reported concentration at which spheri- cal-to-rod micelle transition occurs. The large deviation of the cmc value of TX-100 in the presence of both the additives has been explained in terms of the greater hydrophobic hydration and hydrogen bonding.

Keywords

Micellization, Gelation, CTAB, TX-100, Additives, Cmc, Tac.

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Vineet Kumar ¹, Mamta Kumari ², S. K. Saha ²

Affiliations
1 Indian Institute Technology Bombay, Powai, Mumbai 400 076, IN
2 Indian Institute of Remote Sensing (ISRO), 4, Kalidas Road, Dehradun 248 001, IN

Abstract

The present study distinguishes the growing areas of basmati and non-basmati rice types using polarimetric target decomposition technique on temporal Synthetic Aperture Radar (SAR) data. Multi-temporal quad-pol RADARSAT-2 data of part of the Indo-Gangetic plains were acquired to analyse the contribution of different scattering components (double bounce, singe bounce and volume scattering) at various crop growth stages of both rice types. A decision tree-based framework has been proposed to segregate both rice types and other major land use-land cover classes by capturing the temporal variations in different scattering components. Both rice types were separated in the study area with user's accuracy of 85.19% and 82.93% for non-basmati and basmati rice respectively.

Keywords

Basmati Rice, Decision-Tree Classifier, Polarimetric Target Decomposition, Synthetic Aperture Radar.

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D. K. Saha ¹, O. N. Mohanty ², S. K. Saha ³, A. B. Chattopadhyay ³

Affiliations
1 TELCO, Jamshadpur, IN
2 National Metallurgical Laboratory, Jamshedpur, IN
3 I. I. T, Kharagpur, IN

Abstract

The high temperature developed during high speed machining and grinding not only limits the tool-life but also deteriorates the quality of the finished product by inducing tensile residual stresses, micro-cracks and structural changes. This problem becomes more critical with the difficult-to-machine materials and when the finished products are used in dynamic loading. In such cases drastic and extreme cooling may be an answer to this problem. In present study liquid nitrogen in the form of a jet is employed on the surface grinding of a number of steels and appreciable improvement is noted mainly through reducing energy consumptions, surface damages and tensile residual stresses.

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