405 research outputs found

    Impact of plankton structure on primary productivity in two beels of West Bengal, India

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    Planktonic community in floodplain wetlands embodies the energy transfer through this phase and indicates trophic status of lake. Originally rich bottom coupled with a conducive physicochemical environment encourages fast colonization of the plankton population. Present investigation was carried out in two floodplain wetlands having characteristics of open (Amda beel) and closed (Suguna beel) system. The physicochemical parameters of water and soil of the investigated heels were by and large conducive for planktonic growth. The density of plankton population varied between 1,346 and 2,170 u/l in Suguna bed whereas in Amda beel it ranged from 1,030 to 1,802 u/l. Seasonal fluctuations in water column were conspicuous and mostly dependent on the replenished resources and volume, A mixed and balanced population of diversified fauna constituted the plankton population of the investigated ecosystems. Mostly the diversity was observed to be maximum during winter seasons with coincidence of favorable temperature, dissolved oxygen and other physico-chemical parameters of water besides optimum solar penetration. Richness of planktonic structure in closed system (Suguna) resulted in higher fish production (1,570,05 kg/ha/yr) than that of open system (Amda) (384.4 kg/ha/yr)

    Some socio-economic aspects of the fishermen of twin pronged floodplain wetlands in West Bengal

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    A socio-economic investigation was carried out in two fishermen cooperative societies namely Purba Helatala Fishermen Co-operative Society (E-1), Barhal Fishermen Co-operative Society (E-2), under Maldah district, West Bengal to which the beels (flood plains) under study belong. A total of 132 member fishermen, which constituted the sample, were personally interviewed. The age group of the fishermen of the sample in E-1 varied between 20 and 66 years whereas in E-2 it was 22 and 61 years. All the members of the sample belonged to Scheduled Caste (SC) community. The primary occupation of all the respondents of both the beels was observed to be fishing (100%). Maximum number of illiterate respondents was observed to 56% in E-2 and 35% in E-1. It has been observed that as many as 38.3% of fishermen were having fishing experience which ranging from 16 to 20 years in E-1 whereas it was 6 - 10 years (36.1%) in E-2. Maximum number of fishermen lived in thatched houses (41.66%) in E-1 whereas in E-2 most of them lived in houses made of corrugated tin/tile shed (41.66%). As many as 41.55% of E-1 and 30.55% of E-2 used dug-out canoes for their fishing. Maximum number of fishermen used cast net with individualistic approach (100%) followed by Gill net (E-1:41.56% and E-2:55.55%). Most of the fishermen of the sample participated in fishing activities for 241 to 270 days (41.66%) in E-2 whereas it was 211 to 240 days (33.33 %) in E-1 in a year. During fishing season as many as 40.0% of the respondents of E-1 earned on an average Rs. 801.00 to Rs. 900.00 per month whereas it was Rs. 901.00 to Rs.1,000.00 (43.05%) in case of E-2. A section of fishermen of the sample borrowed money often (51.6%) E-1 whereas it was most often (27.27%) of E-2. The respondents of E-2 made regular repayment of the loan to the maximum extent (79.48%) whereas it was 57.44% in E-1. Higher fish production vis-a-vis higher income for the fishermen was observed in the beel (E2) having close characteristic

    Extractive spectrophotometric determination of microgram amounts of palladium with iodide and cetyltrimethylammonium bromide

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    443-444The coloured complex formed between palladium(II), iodide and cetyltrimethylammonium bromide, is extractable into chloroform. Absorbance, measured at 340 nm, shows a linear response upto 5 ppm of palladium. Molar absorptivity of the complex, based on palladium content, is 2.038 x 104 dm3 mol-1 cm-1 and Sandell's sensitivity is 0.0052, μg/cm2. The influence of foreign ions has been studied

    Extractive Spectrophotometric Determination of Palladium(II} Using Mixed Ligand Complex Formation with Pyridine/ɑ-Picoline/β-Picoline/γ-Picoline/2, 4, 6-Collidine & Iodide

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    181-182Palladium(II) forms complexes with pyridine/ɑ-picoline/β- picoline/γ-picoline/2,4,6-collidine in presence of potassium iodide. These are extractable into chloroform and absorb at 354- 360 nm. The molar absorptivities of the complexes are in the range 1.6-1.9 x 104 l mol-1 cm-1. The formation of these complexes has been utilized to propose an extractive spectrophotometric method of determination of palladium. The notable metal interference is due to mercury. Use of other common organic solvents provides no special advantages

    Surface Tension at Finite Tempearture in the MIT Bag Model

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    At T=0 T = 0 the surface tension σ1/3 \sigma ^{1/3} in the MIT bag model for a single hadron is known to be negligible as compared to the bag pressure B1/4 B^{1/4}. We show that at finite temperature it has a substantial value of 50 - 70 MeV which also differ from hadron to hadron. We also find that the dynamics of the Quark-Gluon Plasma is such that the creation of hybrids (ssˉg)(s\bar{s}g) with massive quarks will predominate over the creation of (ssˉ) (s\bar{s}) mesons.Comment: Substantial changes in the revised version and a new author included, 13 pages in Latex and one figur

    Stage-variations of anandamide hydrolase activity in the mouse uterus during the natural oestrus cycle

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    Recent studies have demonstrated that the endogenous cannabinoids are important modulators of fertility in mammals. In particular, a role of the endocannabinoid system in early stages of embryo development, oviductal transport of embryos, pregnancy maintenance and labour has been demonstrated in rodents and/or in humans. In the present paper, we report the analysis of FAAH activity and protein content in the mouse uterus as a function of the natural oestrus cycle stages. Variations of FAAH activity are discussed in relationship to changes in sex steroid levels and to the possible action of AEA on remodelling of uterine tissues

    Thermal Analysis of Potted Litz Wire for High-Power-Density Aerospace Electric Machines

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    Increasing the power density and efficiency of electric machines (motors and generators) is integral to bringing Electrified Aircraft (EA) to commercial realization. To that end an effort to create a High Efficiency Megawatt Motor (HEMM) with a goal of exceeding 98% efficiency and 1.46 MW of power has been undertaken at the NASA Glenn Research Center. Of the motor components the resistive losses in the stator windings are by far the largest contributor (34%) to total motor loss. The challenge is the linear relationship between resistivity and temperature, making machine operation sensitive to temperature increases. In order to accurately predict the thermal behavior of the stator the thermal conductivity of the Litz wire-potting-electrical insulation system must be known. Unfortunately, this multi material system has a wide range of thermal conductivities (0.1 W/m-K 400 W/m-K) and a high anisotropy (axial vs transverse) making the prediction of the transverse thermal conductivity an in turn the hot spot temperatures in the windings is difficult. In order to do this a device that simulates the thermal environment found in the HEMM stator was designed. This device is not unlike the motorettes (little motors) that are described in IEEE standards for testing electrical insulation lifetimes or other electric motor testing. However, because the HEMM motor design includes significant rotor electrical and thermal considerations the term motorette was not deemed appropriate. Instead statorette (or little stator) was adopted as the term for this test device. This paper discussed the design, thermal heat conjugate analysis (thermal model), manufacturing and testing of HEMM's statorette. Analysis of the results is done by thermal resistance network model and micro thermal model and is compared to analytical predictions of thermal conductivity of the insulated and potted Litz wire system
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