Informatics Publishing Limited

Krishna Lal , R. Dayal

Abstract

The wood structure of Clematis barlellata Edgw. belonging to the family Ranninculaceae has been described in detail. The occurrence of radial vessels and perforated ray cells has been reported for the first time in this species.

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Man Mohan Singh , S. K. Purkayastha , P. P. Bhola , Krishna Lal , Swarna Singh

Abstract

Fibre morphology and pulp strength of twelve species of bamboos grown in the arboratum of the Forest Research Institute, Dehra Dun were studied in two sets of pulps. In all the species fibre dimensions and particularly lumen width were found to vary widely indicating highly heterogenous nature of the pulp. The fibre dimensions were also significantly different in the two sets. Parenchyma proportions were also found to be different in the two sets. No marked differences were found in the various species as regards chemical composition of either chips or pulps, as well as alkali consumed during pulping. But, wide differences were found in strength properties, in unbeaten and beaten pulps of the 12 species of bamboos studied. However, these differences were considerably reduced on beating. As the ranking of tbe species on the basis of strength in unbeaten and beaten conditions is different strength of beaten pulp cannot be predicted from the unbeaten one. Further, significant differences were observed between the two sets of pulps in both unbeaten and beaten hand sheets. No relationships could be found between the fibre characteristics and the pulp strength properties, It appears from this study that because of wide variations within a species, fibre characteristics cannot be used as a criterion for classifying the bamboos for paper and pulp production. On the basis of pulp yield, alka1i consumption and sheet properties of the 12 species, they have been graded and Dendrocalamus hamiltonii has been found to be the best.

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S. K. Purkayastha , Krishna Lal , K. Ramesh Rao , G. S. Negi

Abstract

Variation in anatomical structure and density has been studied in the main hole of a 25 year old tree of Michelia champaca grown at Newforest, Dehra Dun. For studying the variation from pith to periphery, consecutive blocks comprising 2-3 rings were taken along one radius and at two heights. For variations from bottom to top, two growth sheaths were investigated at eight levels. All anatomical data except fibre length were collected from cross sections by the point sampling method. There is no evidence of any consistent pattern in the variation in anatomical structure within the tree. However the fibre length shows a tendeney to increase from the pith outwards and to decrease from the bottom upwards though the trend in both cases is somewhat irregular. Density values within the tree also show a similar irregular trend. Both anatomical structure and density on the whole vary within rather narrow limits within a growth sheath except near the ground level. Study of the correlation between anatomical structure and density has shown that wall thickness, diameter and length of fibres account for 77 per cent of the variation in density. The proportion of fibres appears to have no significant effect on density.

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Krishna Lal ¹

Affiliations
1 G/3, Beyond Ladies Colony, Banaras Hindu University, Varanasi 5, IN

Abstract

The unsteady laminar fluid flow in boundary layers where oscillations are imposed were discussed by Lighthill (3) in 1954. Messiha (4) discussed the free convection problem for the laminar boundary layers from a vertical flat plate with constant suction. Pop (5) has discussed the unsteady Hydromagnetic free convection flow from a vertical infinite flat plate if suction be assumed constant. Lai (1) has considered the Hydromagnetic free convection flow under variable suction in detail for the oscillatory type motion.

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