660 research outputs found

    Snow cover, snowmelt and runoff in the Himalayan River basins

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    Not withstanding the seasonal vagaries of both rainfall amount and snowcover extent, the Himalayan rivers retain their basic perennial character. However, it is the component of snowmelt yield that accounts for some 60 to 70 percent of the total annual flow volumes from Hamilayan watersheds. On this large hydropotential predominantly depends the temporal performance of hydropower generation and major irrigation projects. The large scale effects of Himalayan snowcover on the hydrologic responses of a few selected catchments in western Himalayas was studied. The antecedent effects of snowcover area on long and short term meltwater yields can best be analyzed by developing appropriate hydrologic models forecasting the pattern of snowmelt as a function of variations in snowcover area. It is hoped that these models would be of practical value in the management of water resources. The predictability of meltwater for the entire snowmelt season was studied, as was the concurrent flow variation in adjacent watersheds, and their hydrologic significance. And the applicability of the Snowmelt-Runoff Model for real time forecast of daily discharges during the major part of the snowmelt season is examined

    Influence of Host Genotype on Uredospore Production and Germinability in Puccinia arachidis.

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    Uredospore production by Puccinia arachidis was studied on inoculated detached leaves of one susceptible and five resistant genotypes of peanut (Arachis hypogaea). Significantly fewer uredospores were produced per unit leaf area and per unit pustule area on the resistant than on the susceptible genotypes. Germinability tests carried out on uredospores from three susceptible, one moderately resistant, and 15 resistant genotypes showed that uredospores from resistant genotypes had significantly lower germinability than those from the moderately resistant and the susceptible genotypes. The significance of uredospore production and germinability in relation to resistance is discussed

    Synthesis and Characterization of Er Doped CaZrO3 Phosphors

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    The present paper reports the synthesis and Photoluminescence (PL) studies of the Er rare earth ions doped in CaZrO3 phosphor at a concentration of 2 mol%. Starting materials like Calcium carbonate (CaCO3), Zirconium oxide(ZrO2),Erbium Oxide (Er2O3). The samples were prepared by the conventional solid-state reaction method, which is the most suitable for large-scale product ion. The received phosphor samples were characterized using XRD, SEM and PL techniques. Undoped CaZrO3 exhibits good photoluminescence emission. The PL emission mainly concentrates around 467 nm, when excited with 254 nm wavelengths. The CaZrO3 phosphor, when doped with Er the PL emission was observed from 400 to 560 nm range peaks around 527 ,531,545 and 553nm with high intensity. The present phosphor can act as host for greenlight emission in compact fluorescent (CFL) and fluorescent lamps

    Seaweed resources of the Tuticorin-Tiruchendur coast, Tamil Nadu, India

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    The southern coast of Tamil Nadu (Mandapam to Kanyakumari) supports luxuriant growth of economic seaweeds. The entire indigenous phycocoUoid industry of the country gets the raw material from this region and during the last two decades, due to indiscriminate harvesting, there has been over-exploitation of the resource. The present paper deals with survey conducted in the first sector from Tuticorin to Tiruchendur during December 1986—March 1987. In this study 58 species of marine algae were recorded of which 7 belong to Chlorophyta, 12 to Phaeophyta and 39 to Rhodophyta besides 3 species of seagrasses namely Cymodocea seiriilata, Halophila ovalis and //. ovata within 650 sq. km area surveyed. The total standing crop of the seaweeds was estimated at 9,100 tonnes (wt.). The estimates for the dominant species are Dictyota maxima 530 t, Sargassum tenerrium 640 t, D. bartayresiana 8601, Selieria rebusta 2,0901 and Hypnea valemiae 2,4301. The seaweed potential for commercial exploitation has been briefly discussed

    Semicommercial scale studies using flotation column and dual extraction column on iron ores of Goa, India

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    Goa state in India is endowed with large deposits of low-grade iron ores, geologically formed from the lower Dharwar super group of Archaean rocks. Petrological studies have revealed that silica and alumina are the main gangue minerals. where alumina exists as fine clay and adherent material interspersed in ore body and in some cases both silica and alumina are interlocked with iron ore particles. The amenability of Columnflotation and Dual Extraction Column to remove such gangue was studied by installing test units at the Greater Ferromet beneficiation plant of M/s. Sociedade De Fomento Industrial Ltd., Goa. A reverse flotation process was adopted wherein gangue minerals containing silica and alumina are floated using cationic collector. Sodium hydroxide and starch were used to regulate the slurry pH and depress the iron ore, respectively. Iron ores of different mines and their mixtures were studied using different cationic collectors. The effect of both process and column parameters on grade and recovery were established. The results clearly suggest that iron ore concentrate assaying 67% Fe and 2% Si02 and Ah03 could be obtained with a recovery of 85-90% by single stage column operation. The better performance of flotation column over Dual Extraction Column in terms of reduction of gangue was also brought out in this study

    Photoelectrochemical studies on the mixed oxides, A<SUB>6</SUB>Nb<SUB>8</SUB>Ti<SUB>2</SUB>O<SUB>30</SUB>(A=Ba,Sr)

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    The photoelectrochemical behaviour of oxide bronzes of the type A6Nb8Ti2O30 (A=Ba, Sr) has been studied. They show good photoactivity with photopotentials of the order of 700-800 mV. The flat band potential has been estimated to be -0&#183;9 V vs SCE. The band gap estimated from the spectral response is 3&#183;1 eV

    Studies on nutritional composition of three colour forms of Kappaphycus alvarezii (Doty) Doty

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    Biochemical composition of seaweeds is known to vary with species and environment. Kappaphycus alvarezii is an important commercial source of carrageenans (gel-forming and viscosifying polysaccharides). The nutritional and mineral composition of three (brown, green and pale yellow) colour forms of edible seaweed K. alvarezii is investigated in the current study. The brown colour form of this seaweed contained highest ash content of (25.99±0.22 %), crude fibre (21.0±0.68 %), and protein (8.92±0.41 %), while, the green form had highest carbohydrate (22.0±0.00 %) and sulphate (5.89±0.00 %) content. On the other hand, the pale yellow colour form had highest lipid content (0.72±0.00 %). Amongst the 17 minerals analyzed, highest total mineral macro-elements (viz. Na, K, Ca and Mg) were recorded in the brown form (18.8±0.71 g/100 g d wt) followed by the pale yellow (17.3±1.07 g/100 g d wt) and green colour form (11.9±1.22 g/100 g d wt). The micro-elements varied within the three colour forms; however, the brown colour form had maximum micro-element content (P, Cd, Pb, As, Hg, Cr, Zn, Cu, Fe, Mn, Co, Mo and Ni; 19.96±0.24mg/100 g d wt), followed by green (8.6±0.64 mg /100 g d wt) and pale yellow form (7.15±0.58mg /100 g d wt). On the basis of this study, it could be said that these three colour forms (i.e. brown, green and pale yellow) of Kappaphycus alvarezii could be utilized as a condiment in the omnivorous diet; however, a daily intake of 5.68 g d wt is recommended in case of the brown form, while in case of the green and pale yellow form a maximum daily intake of 9.55 and 10.5 g d wt, respectively is recommended. The study also reveals that the three colour-forms differed in their nutritional and mineral composition
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