42 research outputs found
Baseline information of reproduction parameters of an amphidromous croaker Johnius coitor (Hamilton, 1822) from Ganga river basin, India with special reference to potential influence of climatic variability
Get PDFReproductive biology of female amphidromous croaker Johnius coitor (Hamilton, 1822) was studied for the first time from various freshwater stretches of Ganga river basin, India in relation to climatic variability. The species showed high spatial variation in reproductive phenology and capable of breeding during pre-monsoon, monsoon, post-monsoon and winter. Water temperature is the most crucial environmental parameter influencing gonadal maturation and breeding. Generalized additive model (GAM) models revealed water temperature near 23–25 °C as optimum and threshold GSI above 3 units necessary for breeding. Pre-spawning fitness (Kspawn50) and size at 50% maturity (LM50) benchmarked through Kaplan-Meier survival fit estimates were in the range 1.27–1.37 units and 19–24.5 cm respectively. First maturity of females was encountered at 11.4 cm within the size range 7.2–28.5 cm. Egg parameters in mature-ripe females ranged between 0.29–0.80 mm (diameter), 0.05–0.19 mg (weight) and 5687–121 849 eggs (absolute fecundity). Mapping of climate preferendum through LOESS smoothing technique hinted water temperatures 32 °C to be detrimental for attainment of pre-spawning fitness while no dependence on rainfall was observed. Based on the climato-hydrological influence on breeding and regional trends of changing climate along river Ganga, we infer minimal climate driven changes in breeding phenology of this amphidromous fish species. Results of this study may serve as baseline information for future studies assessing climate driven changes and evolutionary adaptations in croakers from river Ganga
Microplastics contamination in East Kolkata Wetlands and drinking water plants
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Continuous carbon nanotube-polycarbonate composite fibers through melt spinning
No full text477-481Among the many potential applications of
carbon nanotubes (CNT), its usage to strengthen polymers has been paid
considerable attention due to the exceptional stiffness, excellent strength and
the low density. This has provided numerous opportunities for the invention of
new material systems for applications requiring high strength and high modulus.
In this paper, composite fibers of polycarbonate (PC) and multiwall carbon
nanotubes (MWNTs) are prepared in dimethyl formamide (DMF) using melt
mixing-coagulation technique followed by melt spinning at 220°C. The spinning
of the coagulated PC-MWNTs is done at various draw ratios and the resultant
fibers are studied by optical microscope, SEM and AFM. The mechanical
properties of the composite fiber are determined and it is found that the
addition of 1-1.5 wt% of MWNT increased the tensile strength of the polymer
fiber from 900 MPa to 1890 MPa and Young’s modulus from 1372 MPa to 2060 MPa.
The results show that the mixing of MWNT with the polycarbonate matrix, above
its melting point followed by coagulation in water might have developed a
strong interfacial bonding between functionalized MWNTs and PC
A new index-based risk assessment disentangling the phytoplankton diversity loss induced by inland navigation?towards framing river water management strategy
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A new index-based risk assessment disentangling the phytoplankton diversity loss induced by inland navigation?towards framing river water management strategy
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