Emerging Character of Metallic Materials

Despite the usefulness of metals, new alternative materials have been appearing on the scene everyday, threatening the metallic monopolies. Innovative deve-lopments in technologies and techniques make metals still the most sought after material for various applications including areas where non-metallic mater- ials were dominating till recently. This paper highli- ghts the technological advances taking place in the area of metallic materials meet to the exacting requ-irements of automobile, marine, space and knowledge based industries

Bumper catch of sea bass, Lates calcarifer (Bloch, 1790) by gill netters in Mumbai waters

Lates calcarifer is commonly called as giant sea bass, sea perch or giant brackish water perch and in Maharastra, locally known as ‘Khajura’ (Waghmare and Sawant, 1994). Sea bass is considered as a valuable seafood delicacy with good demand in market. They are found in coastal waters, estuaries and lagoons usually at a depth of 40 m and mainly feed on fishes and crustaceans

IN VITRO ANTIOXIDANT CAPACITY OF THE FERN, DRYNARIA QUERCIFOLIA (L) SM., RHIZOME EXTRACT

Objective: The study was aimed to evaluate polyphenolic composition and antioxidant properties of methanol extract of rhizome of Drynaria quercifolia (L.) Sm. Methods: In this study, assessment of total phenolic and flavonoid contents were performed using Foiln-Ciocalteu and Aluminium chloride methods respectively. Antioxidant capacity of crude methanolic extract of rhizome of D. quercifolia were examined using established 1,1 – diphenyl – 2-picrylhydrazyl stable free radical (DPPH∙) assay, hydroxyl ion radicals (˙OH), nitric oxide (NO), hydrogen peroxide (H2O2)and 2, 2'-Azinobis (3-ethylbenzothiazoline sulphonic acid) ABTS•+ scavenging assays.  Results: The extract yielded total phenolic content (TP) of 240 ± 0.01 mg gallic acid equivalents (GAE)/100g of fresh mass (FM) and total flavonoid content (TF) of 150 ± 0.02 mg quercetin equivalents (QE)/100g of fresh mass (FM). The extract of D. quercifolia rhizome exhibited remarkable scavenging capacity towards DPPH∙ (EC50 18.54 ±0.70 µg mL-1), ˙OH (EC50 37.60±0.41 µg mL-1) NO (EC50 42.40 µg mL-1), H2O2 (EC50 32.80±1.89 µg mL-1) and ABTS•+ (EC50 29.80 ±0.70 µg mL-1). The antioxidant capacities of the extract were comparable and stronger than that of the antioxidant standard, butyl hydroxy toluene (BHT). The findings were also comparable with antioxidant properties of other medicinal ferns which are discussed in the study. Conclusion: Significant and positive correlations (R2 0.999-0.862) were observed between polyphenolic contents and the antioxidant capacities, indicating that the phenolics were major contributors of the antioxidant property. Thus, the methanol extract from the rhizome of D. quercifolia indicated the existence of strong antioxidants and it can be used as tonic

Phase diagram of the metal-insulator transition in 2D electronic systems

We investigated the interdependence of the effects of disorder and carrier correlations on the metal-insulator transition in two-dimensional electronic systems. We present a quantitative metal-insulator phase diagram. Depending on the carrier density we find two different types of metal-insulator transition - a continuous localization for rs=<8 and a discontinuous transition at higher rs. The critical level of disorder at the transition decreases with decreasing carrier density. At very low carrier densities we find that the system is always insulating. The value of the conductivity at the transition is consistent with recent experimental measurements. The self-consistent method which we have developed includes the effects of both disorder and correlations on the transition, using a density relaxation theory with the Coulomb correlations determined from numerical simulation data.Comment: 4 pages, RevTeX + epsf, 5 figures. New comments on conducting phase and on the conductivity. References updated and correcte

Model for Glass Transition in a Binary fluid from a Mode Coupling approach

We consider the Mode Coupling Theory (MCT) of Glass transition for a Binary fluid. The Equations of Nonlinear Fluctuating Hydrodynamics are obtained with a proper choice of the slow variables corresponding to the conservation laws. The resulting model equations are solved in the long time limit to locate the dynamic transition. The transition point from our model is considerably higher than predicted in existing MCT models for binary systems. This is in agreement with what is seen in Computer Simulation of binary fluids. fluids.Comment: 9 Pages, 3 Figure

Population dynamics and stock assessment of grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-west coast of India

The life history and exploitation parameters of Rhizoprionodon oligolinx Springer, 1964 were assessed using commercial landing data of 2012-2015 from Mumbai waters of India to understand the population dynamics and stock status of the species. The average annual landing of the species was estimated to be 383 t, which formed about 9.1% of the total shark landings of Maharashtra. L∞, K and t0 estimated were 97.1 cm, 0.47 yr-1 and -0.79 yr respectively. Total mortality (Z), fishing mortality (F) and natural mortality (M) rates were estimated as 2.16 yr-1, 1.48 yr-1 and 0.69 yr-1 respectively. The length at capture (L50), length at female maturity (Lm50) and male maturity (Lm50) were estimated as 49.7, 62.3 and 59.5 cm respectively, which indicated that most of the sharks entered peak phase of exploitation before attaining sexual maturity. Length-weight relationship indicated allometric growth (b>3) for the species. The species was found to be a continuous breeder and showed peak recruitment during April. The current exploitation rate (Ecur) was found to be 0.68, which is lower than Emax estimated for the species using Beverton and Holt yield per recruit analysis. Thompson and Bell prediction model showed that at current exploitation level, the biomass (B) has reduced to 32% of virgin biomass (B0) where as, the spawning stock biomass (SSB) has reduced to 16% of the virgin spawning stock biomass (SSB0). Hence the exploitation level for the species should be reduced by 40% that will ensure the availability of SSB at a relatively safer 30% level to rebuild the stock for long term sustainability of the resource