Propagation of high amplitude higher order sounds in slightly soft rectangular ducts, carrying mean flow

The resonance expansion method, developed to study the propagation of sound in rigid rectangular ducts is applied to the case of slightly soft ducts. Expressions for the generation and decay of various harmonics are obtained. The effect of wall admittance is seen through a dissipation function in the system of nonlinear differential equations, governing the generation of harmonics. As the wall admittance increases, the resonance is reduced. For a given wall admittance this phenomenon is stronger at higher input intensities. Both the first and second order solutions are obtained and the results are extended to the case of ducts having mean flow

Site and species selection criteria for cage culture

Site selection is the most important factor which determines the commercial viability of mariculture systems. Cage culture can be made possible only when the site for cage culture operation is located, designed and operated to provide optimum water quality and to avoid stress conditions. In addition to water and sediment quality of the site some biological and natural distribution information for the species should also be known before a site is selected for cage culture. The selection of fish for cage culture should be based on biological criteria, such as physiological, behavioural characteristics and level of domestication; marketing criteria and environmental criteria, distribution and habitat of sit

Heavy metal distribution in the biotic and abiotic matrices along Karnataka coast, west coast of India

Sediment and soft tissue of bivalve samples collected from various sites of Karnataka coast were analysed for the estimation of the nanaal and anthropogenic heavy metal fluxes. Seasonal variations of heavy metals in sediment and bivalves collected from selected hot spots from Binage, Karwar and Thannirbavi, Mangalore were monitored. High concentrations of Hg was observed in the environment near' the vicinity of a caustic soda plant at Binage, Karwar, indicating Hg pollution. Total Hg concentration in the tissue of oysters sampled from a contaminated stream from the above site, exceeded the safe limit of 0.5 ilg g.1 wet weight. The base-line heavy metal concentrations in sediment and bivalves from selected sites of coastal Karnataka are presented

Sperm whale Physeter macrocephalus washed ashore at Devbagh, Karnataka

A female sperm whale Physeter macrocephalus was stranded and washed ashore in dead condition, at Devbagh, 10 km away from Karwar on 18.9.2009

Some aspects of nursery rearing of the Asian seabass (Lates calcarifer, Bloch) in indoor cement tanks

Asian seabass (Lates calcarifer) is a highly valued food fish of great culture potential. Nursery rearing of Asian seabass in indoor cement tanks was undertaken. Fish were fed on artificial diets at 4% body weight and four times feeding per day with periodical size grading. Mean weight and length at the end of the 45 days experimental period was 8.55 g and 91.03 mm, respectively. While survival rate was 100%, FCR and PER at the end of the 45 days experimental period was 1.15 and 1.07%, respectively. The results of various growth parameters studied showed that the values obtained were in conformity with earlier reports on nursery rearing of Asian seabass under varied rearing systems and growth conditions

Non-spherical collapse of a two fluid star

We obtain the analogue of collapsing Vaidya-like solution to include both a null fluid and a string fluid, with a linear equation of state ($p_{\bot} = k \rho$), in non-spherical (plane symmetric and cylindrically symmetric) anti-de Sitter space-timess. It turns out that the non-spherical collapse of two fluid in anti-de Sitter space-times, in accordance with cosmic censorship, proceed to form black holes, i.e., on naked singularity ever forms, violating hoop conjecture.Comment: 7 pages, RevTeX 4, minor correction

Abundance of natural fish seed resources prioritized for mariculture in the Kali estuary

Mariculture is a promising fish producing industry in India with cage farming of marine finfish and shellfish becoming popular along the entire coast. Fish seed availability is the need of the hour for sustaining and supporting expansion of cage farming of fishes in India. Capture Based Aquaculture (CBA), can be considered as an economic activity for fishermen communities to practise where by accessing natural fish seed resources for culture, it enhances the fish production, yield and market value

Current Oscillations, Interacting Hall Discs and Boundary CFTs

In this paper, we discuss the behavior of conformal field theories interacting at a single point. The edge states of the quantum Hall effect (QHE) system give rise to a particular representation of a chiral Kac-Moody current algebra. We show that in the case of QHE systems interacting at one point we obtain a ``twisted'' representation of the current algebra. The condition for stationarity of currents is the same as the classical Kirchoff's law applied to the currents at the interaction point. We find that in the case of two discs touching at one point, since the currents are chiral, they are not stationary and one obtains current oscillations between the two discs. We determine the frequency of these oscillations in terms of an effective parameter characterizing the interaction. The chiral conformal field theories can be represented in terms of bosonic Lagrangians with a boundary interaction. We discuss how these one point interactions can be represented as boundary conditions on fields, and how the requirement of chirality leads to restrictions on the interactions described by these Lagrangians. By gauging these models we find that the theory is naturally coupled to a Chern-Simons gauge theory in 2+1 dimensions, and this coupling is completely determined by the requirement of anomaly cancellation.Comment: 32 pages, LateX. Uses amstex, amssymb. Typos corrected. To appear in Int. J. Mod. Phys.

Radioactive isotopes reveal a non sluggish kinetics of grain boundary diffusion in high entropy alloys

High entropy alloys (HEAs) have emerged as a new class of multicomponent materials, which have potential for high temperature applications. Phase stability and creep deformation, two key selection criteria for high temperature materials, are predominantly influenced by the diffusion of constituent elements along the grain boundaries (GBs). For the first time, GB diffusion of Ni in chemically homogeneous CoCrFeNi and CoCrFeMnNi HEAs is measured by radiotracer analysis using the $^{63}$Ni isotope. Atom probe tomography confirmed the absence of elemental segregation at GBs that allowed reliable estimation of the GB width to be about 0.5 nm. Our GB diffusion measurements prove that a mere increase in number of constituent elements does not lower the diffusion rates in HEAs, but the nature of added constituents plays a more decisive role. The GB energies in both HEAs are estimated at about 0.8-0.9 J/m$^2$, they are found to increase significantly with temperature and the effect is more pronounced for the CoCrFeMnNi alloy.Comment: 11 pages, 9 figure

Charged null fluid collapse in anti-de Sitter spacetimes and naked singularities

We investigate the occurrence of naked singularities in the spherically symmetric, plane symmetric and cylindrically symmetric collapse of charged null fluid in an anti-de Sitter background. The naked singularities are found to be strong in Tipler's sense and thus violate the cosmic censorship conjecture, but not hoop conjecture.Comment: 8 pages, No figure