Concave grating spectrometer Patent

Concave grating spectrometer for use in near and vacuum ultraviolet region

Modeling of plate flexure satisfying normal stress conditions at the plate surfaces

Modeling of plate flexure, based on cubic variation of inplane displacements and quartic variation of the normal displacement has been discussed. Displacement functions satisfy the zero shear stress condition at top and bottom surfaces of the plate. The normal stress condition at the surfaces of the plate and the elemental equilibrium eqUlltions are enforced through the use of the Lagrangian multipliers in the variational procedure used. Several new models are available as special cases in this formulation. An illustrative example of a simply-supported plate subjected to sinusoidal loading is included to indicate relative merits of the special cases

Kinetics of Oxidation of Methyl Orange & Methyl Red by V(V)*

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Taxonomy of the fishes of the family Leiognathidae (Pisces, Teleostei) from the West coast of India

Taxonomy of the fishes of the family Leiognathidae (Pisces, Teleostei) from the West coast of Indi

Reproductive biology of Leiognathus splendens (Cuvier) from Kochi, south-west coast of India

The reproductive biology of Leiognathus splendens (N = 2112) was studied using the samples collected from the Kerala coast during 1998 - 2000. A separate scale of five stages of maturation has been developed for the first time for any Indian marine fish and applied in the present study. Analysis of data on the ova diameter in different length groups showed that spawning takes place in batches at regular intervals after the juveniles undergo the process of maturation and reach ripe stage. Spawning takes place almost round the year. The length at first maturity was 75 mm. The estimated fecundity ranges from 5715 (88 mm TL) to 37160 (106 mm TL)

Maturity and spawning of Secutor insidiator along the Kerala coast

The reproductive biology of Secutor insidiator (N=1546) was studied from samples collected along Kerala during October 1998-December 1999. A separate scale of five stages of maturity has been developed. Analysis of data on the ova of different stages of maturation in different length groups and months showed that spawning takes place in batches regularly at intervals after the juveniles undergo the process of maturation and reach ripe stage. The length at first maturity was estimated at 75 mm. This species has a protracted spawning season extending almost throughout the year

Age and growth studies in silverbellies along Kerala coast

Age and growth were estimated for five species of silverbellies from samples collected for 24 months from January 1998 along Kerala coast. The estimated values of von Bertalanffy growth parameters are: Eubleekeri splendens L∞ = 154 mm, K = 0.52; Leiognathus brevirostris L∞ = 140 mm, K = 0.86; Secutor insidiator L∞ = 130 mm, K = 0.80; S. ruconius L∞ = 92 mm, K = 1.19 and Gazza minuta L∞ = 160 mm, K = 1.7. Length-weight relationship of E. splendens W = 0.000006 L3.163977, S. insidiator W = 0.0000015 L3.463096 and S. ruconius was W = 0.000162 L2.973626. The Kn value in E. splendens is lowest in the 75-79 mm length group and highest in 100-104 mm length group. In S. insidiator the Kn value is highest in the 60-64 mm length group. A review of methods available for study of growth has been made and the limitations are discussed. In the ELEFAN method, which has been followed in the present work, the issues confronted are discussed and the ways by which accurate growth parameters could be estimated are discussed

Fishery and population dynamics of silverbellies along the Kerala coast

The fishery of silverbellies along the Kerala coast has been described bringing out various craft gear combinations and the seasonal variation in abundance of different species. The Beverton-Holt yield per recruit analysis was made in all the five species that contribute to the commercial fisheries and the Fmax under the current tc and tmax under the current F have been determined and the status of the stocks of each species brought out. In all the five species the Fmax is shown to be less than the present F and the current age at first capture is less than the value that leads to increase the yields. Mixed fisheries assessment has been carried out in five species, which constitute about 90% by weight of silverbelly landings and the maximum equilibrium yield that could be taken was determined. The maximum equilibrium yield could be achieved at 25% of current fishing effort level and the current tc. Similarly, maximum equilibrium yield of silverbellies could be obtained at 200% of the current codend mesh size keeping the current effort constant

Nitrogen isotopes in mantle-derived diamonds: indications of a multi-component structure

Mantle nitrogen trapped in diamonds is commonly defined by an isotopic composition (δ15N) of ~-5% based on the central tendency of total combustion diamond data that vary from -25 to +18%. We present here the nitrogen isotopic data from stepped combustion of diamonds, which together with data from other mantlederived materials suggest a multi-component structure of diamond-nitrogen. Mantle nitrogen sampled in diamonds apparently has δ15N ~-15%, similar to that observed in mantle xenoliths and mid-oceanic ridge basalts (MORBs), while nitrogen in a minor population of diamonds from China is consistent with contributions from an ocean island basalt like mantle source

Structural behaviour of tapered rods subjected to axial compressive loads in the post-buckling range

The equation governing the behaviour of rods of variable cross-section subjected to compressive load" is deduced using the classical assumption-that the plane sectioIis of the rod before bending remain plane even after bending; the stress-strain relationship can be either the conventional Ramberg-Osgood Law or the alternative form developed by Rao and Krishna Murthy; the deformations are considered to be large, 'The governing equation is nonlinear and an iterative' method is used to obtain numerical results. A dass of rods whose variation of the cross-section ,can be represented by I=I0(1-βS)n(where s is the curvilinear coordinate) are considered to study,the post-buckling behnviour. Numerical results have been obtained for various values of the geometric parameters involved in the problem, and the results are in good agreement with those available in the literature