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A. Samanta ¹, D. K. Chattoraj ¹

Affiliations
1 Department of Food Technology & Biochemical Engineering, Judavpur University, Calcatta 700032, IN

Abstract

The interfacial tension (γ) of heptane-water system has been measured as functions of time (t) at a fixed concentration (C^l_p) of protein bovine serum albumin at a given value of pH, ionic strength and temperature. The concentration C^l_s of anionic surfactant SDS and those of cationic surfactant cetyl trimethyl ammonium bromide cetyl pyridinium bromide, myristyl trimethyl ammonium bromide and dodecyl trimethyl ammonium bromide respectively have been kept constant during the measurement of interfacial tension lowering (Π). From the rate of change of Π with t, the first order rate constants k₁ and k₂ for the adsorption process have been evaluated for low and high ranges of time. Values of k₁ depend upon magnitude of C^l_s. pH and ionic strength of the medium. The effect of hydrocarbon chain length and the nature of hydrophillic group of the surfactant, on k₁ have been examined at different values of pH and ionic strength of the medium. The values of k₂ are found to be insensitive to the charge of all these parameters reason of which has been discussed. The data have been analysed by Ward-Tordai-McRitchi-Alexander equation for the estimation on area (ΔA) swept out by surfactant bound protein molecule during the protein adsorption at oil-water interface.

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M. K. Bera ¹, Kasturi Bhattacharya ¹, A. Sarkar ², A. Samanta ², Kishor Kumar ³, Ashok Sahni ⁴

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur - 721 302, IN
2 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur -721 302, IN
3 Wadia Institute of Himalayan Geology, Dehradun - 248 001, IN
4 Centre of Advanced Study in Geology, Panjab University, Chandigarh - 160 014, IN

Abstract

Oxygen isotope composition (δ¹⁸O) of fossil bone and tooth enamel phosphate (bioapatite) is an important tool for estimating the isotopic composition of past environmental water. Lack of analytical facility was a hindrance for studying such bioapatites in spite of large number of fossil materials reported from various geological ages in India. We have established in our laboratory, based on available methods, the chemical procedure for extraction of very small amount (<1000 μg) PO₄ ^-3 from bioapatite and on-line mass spectrometric measurement of its δ¹⁸O composition by high temperature (∼1450 °C) pyrolysis. The achieved precision is ∼± 0.3 ‰ similar to obtained elsewhere, with interlaboratory calibration showing excellent agreement of standard phosphates. Inferred δ¹⁸O values of environmental water, based on the analysis of teeth and bones of sharks, fish and terrestrial mammals from the Paleogene successions of the northwest sub-Himalayan and the Peninsular India show strong correspondence with animal habitats. The freshwater δ¹⁸O values are much depleted having range similar to modern monsoon precipitation. However, owing to our small dataset it is not possible at this stage to infer about the existence of monsoon over the Indian sub-continent during the Eocene-Oligocene time.

Keywords

Phosphate, Pyrolysis, Oxygen Isotope, Monsoon.

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A. Samanta ¹, D. Chatterjee ², G. Sutradhar ²

Affiliations
1 Central Tool Room Training Centre, BonHooghly Industrial Area, Kolkata 700108, IN
2 Mechanical Engineering, IN

Abstract

With the outbreak of industrial revolution the trend in large scale production for domestic as well as foreign market has set in. Developed countries can invest huge money in design and R&D to develop their products, but due to trade liberalization the competition becomes stiffer and under developed countries are facing lot of problems to meet the standards for global markets.

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A. Samanta

Abstract

The term Fatigue is often used with different meanings; it is applied in such a diversity of context that it has led to a confusion of ideas. Fatigue can be considered simply as a decrease in physical performance, or as a condition affecting the whole organism. It includes such factors as subjective, feeling of fatigue, motivation, and any resulting deterioration of mental and physical activities.

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