Comparative catching efficiency of traditional prawn fishing gears in Pulicat lake of Tamil Nadu, India

303-310Prawn fishery in Pulicat Lake has a significant role in livelihood of the fishers, which is being harvested through different fishing gears. Here, we investigated the prawn-fishing gear and their catch composition. The information on various aspect about the gears was collected from the 48 respondents each month through pre-designed interview schedule by adopting random sampling. Results revealed that the quantity of prawn were higher in stake net (209.83 kg), followed by barriers (118.58 kg), drive-in-net (55.58 kg) tangle net (18.25 kg) and was statically significant at 5 %. It was estimated that more than half (52.16 %) of the total prawn catch in Pulicat Lake was obtained through stake net than the barriers (29.48 %), drive-in-net (13.82 %) and tangle net (4.54 %). The maximum quantity of prawn was obtained during the November and December in all the prawn-fishing gear (p < 0.05). This study concludes that non-selective fishing gears resulted in the abundant catch of juvenile fishes and crabs, need to be regulated mesh size, to support the conservation and sustainable harvest of the fishery resources in Pulicat Lake

Microstructural and mechanical characterisation of laser-welded high-carbon and stainless steel

The final publication is available at Springer via http://dx.doi.org/10.1007/s00170-015-7111-5Laser welding is becoming an important joining technique for welding of stainless steel to carbon steel and is extensively used across various sectors, including aerospace, transportation, power plants, electronics and other industries. However, welding of stainless steel to high-carbon steel is still at its early stage, predominantly due to the formation of hard brittle phases, which undermine the mechanical strength of the joint. This study reports a scientific investigation on controlling the brittle phase formation during laser dissimilar welding of high-carbon steel to stainless steel. Attempts have been made to tailor the microstructure and phase composition of the fusion zone through influencing the alloying composition and the cooling rate. Results show that the heat-affected zone (HAZ) within the high-carbon steel has significantly higher hardness than the weld area, which severely undermines the weld quality. To reduce the hardness of the HAZ, a new heat treatment strategy was proposed and evaluated using a finite element analysis-based numerical simulation model. A series of experiments has been performed to verify the developed thermo-metallurgical finite element analysis (FEA) model, and a qualitative agreement of predicted martensitic phase distribution is shown to exist

Evolution of microstructure and crystallographic texture during dissimilar friction stir welding of duplex stainless steel to low carbon-manganese structural steel

Electron backscattered diffraction (EBSD) was used to analyze the evolution of microstructure and crystallographic texture during friction stir welding of dissimilar type 2205 duplex stainless steel (DSS) to type S275 low carbon-manganese structural steel. The results of microstructural analyses show that the temperature in the center of stirred zone reached temperatures between Ac 1 and Ac 3 during welding, resulting in a minor ferrite-to-austenite phase transformation in the S275 steel, and no changes in the fractions of ferrite and austenite in the DSS. Temperatures in the thermomechanically affected and shoulder-affected zones of both materials, in particular toward the root of the weld, did not exceed the Ac 1 of S275 steel. The shear generated by the friction between the material and the rotating probe occurred in austenitic/ferritic phase field of the S275 and DSS. In the former, the transformed austenite regions of the microstructure were transformed to acicular ferrite, on cooling, while the dual-phase austenitic/ferritic structure of the latter was retained. Studying the development of crystallographic textures with regard to shear flow lines generated by the probe tool showed the dominance of simple shear components across the whole weld in both materials. The ferrite texture in S275 steel was dominated by D 1, D 2, E, E¯ , and F, where the fraction of acicular ferrite formed on cooling showed a negligible deviation from the texture for the ideal shear texture components of bcc metals. The ferrite texture in DSS was dominated by D 1, D 2, I, I¯ , and F, and that of austenite was dominated by the A, A¯ , B, and B¯ of the ideal shear texture components for bcc and fcc metals, respectively. While D 1, D 2, and F components of the ideal shear texture are common between the ferrite in S275 steel and that of dual-phase DSS, the preferential partitioning of strain into the ferrite phase of DSS led to the development of I and I¯ components in DSS, as opposed to E and E¯ in the S275 steel. The formations of fine and ultrafine equiaxed grains were observed in different regions of both materials that are believed to be due to strain-induced continuous dynamic recrystallization (CDRX) in ferrite of both DSS and S275 steel, and discontinuous dynamic recrystallization (DDRX) in austenite phase of DSS

The Comparison of Two Prognostic Scores PRISM III and PIM II in a Pediatric Intensive Care Unit

BACKGROUND: Pediatric Intensive Care Unit is specialized area in care of critically ill infant and children. Many prognostic scores are used to evaluate outcome in PICU.PRISM III and PIMII are the recent versions used in pediatric populations. OBJECTIVES: To compare the performance of PRISM III and PIM II in sick children in a Pediatric Intensive Care Unit and their relation between predicted mortality and observed mortality. METHODS: A prospective study was conducted at Pediatric Intensive Care Unit, Chengalpattu, over a period of one year from July 2018 to July 2019.A total of 102 children were enrolled during study period. Within first hours of admission PIM II was assessed and at 24 hours PRISM III score was assessed. Children were followed up for outcome measured in survival and death. RESULTS: A total of 102 children were included in this study. Among 102 children 18 children were died and 84 children were survived. Mean age was 37.6 months, ,majority of children died were infants and female children but there was no statistical significance influence on outcome. The overall estimated mortality was 9 and 7 with PRISM III and PIM II respectively compared with observed mortality of 18.PRISM III and PIM II had poor calibration.However PRISM III (ROC-0.881) and PIM II (0.768) showed the better discriminatory power to predict survival and death. CONCLUSION: In this study PRISM III and PIM II underestimate the mortality in comparison to observed mortality. However both scores helps in discriminating cases between survival and death. PRISM III is better than PIM II in terms of risk stratification in PICU

Characterization of hydrophobic coating developed by micro arc oxidation on AA2014 alloy

325-330The interest in aluminum alloys is on account of their attractive properties and high strength to weight ratio. In marine environments aluminum alloys especially AA2014, exhibit low corrosion resistance. Micro arc oxidation (MAO), a novel technique, has gained popularity for synthesizing ceramic coatings by electrochemical treatment using an aqueous electrolyte on aluminum, magnesium, titanium and their alloys and it can be a method of improving corrosion resistance of aluminum alloys. In this study, a stable film is produced on the substrate of AA2014 aluminum alloy by MAO in an aqueous electrolyte having chemically treated with myristic acid. Corrosion properties of these treated and untreated surfaces are evaluated in freshly prepared 3.5% NaCl solution by potentiodynamic polarization test. The electrochemical measurements showed that the MAO treatment significantly reduced the corrosion current densities (Icorr) and simultaneously enhanced the corrosion potential (Ecorr) values indicating that the surface becomes nobler than the untreated one. The surface morphology of the coatings is characterized by scanning electron microscope (SEM). Hydrophobicity of these coatings is evaluated by means of contact angle measurement by goniometer. XRD test is also done on the sample to find out present elements on the coating. For one of the treated surfaces the static contact angle for water is measured to be approximately 129°. Thus the coatings are found to offer excellent corrosion resistance combined with hydrophobic property