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A. Raizada , A. K. Parandiyal , B. N. Ghosh

Abstract

The paper deals with the estimation of C flux through litterfall (total and leaf litterfall alone) in forest plantations of India, occurring in four major forest groups of India. Using published studies covering 82 stands and 24 species raised as plantations, the annual C flux rates were computed. The C flux rates (M t C/yr) from total litter were 2.17, 1.18, 1.60 and 2.30 in tropical moist deciduous forests, tropical dry deciduous forests, montane sub-tropical forests and montane temperate forests, respectively. The C flux rates from leaf litter alone were highest (3.03 M t C/year) in montane sub-tropical forests. Results indicate that plantations of short rotation tree species with regular leaf shedding patterns have more C sequestering capacity than species with unimodal or bimodal leaf shedding patterns. Such species could be raised in wastelands for twin purposes - biomass production and carbon sequestering.

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B. N. Ghosh ¹

Affiliations
1 80 Regent Estate, Calcutta-700 092, IN

Abstract

It is generally assumed that in aqueous solution each particle or macromolecule of the colloidal electrolyte is surrounded by an ion-atmosphere in which the number density of the counterions is greater than that of the co-ions, but the particle or the macro molecule with its ion-atmosphere, as a whole, is electrically neutral and that the thickness of the ion-atmosphere is small compared to the distance between the centres of two neighbouring particles except when the concentration of the colloid is very high. Starting with this simplified picture and assuming further that in a highly purified colloidal solution the thickness of the ion atmosphere and the activities of the (diffusible) ions in the inter micellar solution do not change appreciably with dilution equations have been deduced to account quantitatively for the variation of (1) counter-ion activity, (2) the specific conductivity and (3) the osmotic pressure with the concentration of the colloidal electrolyte. The equations have been subjected to test using the data available in the literature on congo red, cetylsulphonic acid benzopurpurin 4B and its isomer prepared from metatolidine, azarectic (neem gum) acid, gum arabic acid, polyacrylic acids, clay acids and their salts and have been found satisfactory. Furthermore, using the aforesaid expression for the variation of specific conductivity with dilution, Smoluchowski's equation for the electroviscous behaviour of colloids has been modified and equations have been deduced to account for the variation of electro-viscosity of solutions of colloidal electrolytes with dilution. These equations have been subjected to test using the data available in the literature on viscosity of sols of sodium thymus nucleate, gum arabic acid, polyacrylic acids of different degrees of polymerisation, silver iodide, bovine serum albumin. β-lactoglobulin, ribonuclease and mono-disperse polystyrene lattices prepared by emulsion polymerisation using Na-stearate and Na-dodecylsulphate as emulsifiers and have been found satisfactory.

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S. K. Banerjee ¹, J. Bhattacharya ¹, B. N. Ghosh ¹

Affiliations
1 National Metallurgical Laboratory, Jamshedpur, IN

Abstract

Welding or joining of metals is probably as old as the invention of metals, when metals, were joined by heating and hammering (forge welding). Despite the early start, progress in the development of welding process was very slow; only in the 19th century, welding of metals was accepted as a potential technology for fabrication of metals, and since then the development work in this field started growing and presently it is considered to be a major fabrication process in the modern industries. With the introduction of more sophisticated and complex materials more and more novel techniques have been introduced for joining metals. Explosive welding is one of the latest techniques in the field of joining metals which can solve many joining problems.

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S. R. Bhattacharya ¹, B. N. Ghosh ¹, P. Som ¹

Affiliations
1 Civil Engineering Department, Jadavpur University, Calcutta-700 032, IN

Abstract

In the last few decades rapid housing development works have progressed both in rural and urban areas. Interiors of the Himalayan region, which, at one time were accessible only to fearless trekkers and pilgrims, are now full with human activities.

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A. K. Maiti ¹, T. K. Ray ², B. N. Ghosh ³

Affiliations
1 National Building Construction Corporation, IN
2 Jadavpur University, IN
3 Civil Engineering Dept., Jadavpur University, IN

Abstract

Most of the domes so far constructed are spherical in shape. But a parabolic dome has some extra advantages over and above those available in the case of a spherical dome. At the same time there is no difference in the method of construction between the two. This paper mainly deals with the comparative analysis of a parabolic dome with a spherical and conical one.

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