Oyster farming

Large quantities of the edible oyster, Crassostrea madrasensis (Fig. 1) growing wildly in most of the tidal creeks and estuarine regions along the east coast of India, are allowed to perish un-exploring the great strides made in this venture by developed nations. The Central Marine Fisheries Research Institute focused its attention in developing systems for the culture of edible bivalves, identifying edible oyster farming and mussel farming as priority areas for Research and Development. Evaluation of the resources potential, identification of suitable water spread and areas for culture, evolving proper techniques to collect required seed for farming, introducing an appropriate method of farming and establishing a model farm formed the broad objectives of the project initiated in 1975 on edible oyster culture. By employing suitable method for spat collection and providing better growing conditions for the seed so collected it appeared distinctly possible to raise large number of oysters achieving faster growth rate and better meat yield. Weighing the pros and cons of the different systems of oyster culture followed in other countries and bearing in mind the local conditions, it was decided to experiment with the 'rack' system of culture

Conductive Strontium Titanate Layers Produced By Boron-ion Implantation

The ion implantation of boron has been found to be an effective method for increasing the conductivity of strontium titanate. A highly conductive layer was formed by implantations at doses of 3.6x1016 to 1.0x1017 ions/cm2, using an accelerating voltage of 100 kV, corresponding to a boron range of about 300 nm. The conductivity of the implanted layer was found to be further enhanced by about four orders of magnitude after annealing at 225 °C. The surface resistivity attained was typically 1000 Ω/square at room temperature. The resistance increased with rising temperature between 77 and 500 K. All samples were found to be n type, as determined by Hall-effect and thermoelectric measurements. The measured Hall mobility range was from 100 cm2/V sec at 77 K, decreasing to 5 cm2/V sec at 300 K. The existence of several defect energy levels can be inferred from the electrical data

Corrections to "pairwise s-normal spaces" rev. colombiana mat. 26 (1992), 25-38

The following corrections are necessary in the paper:1. Example 2.1.1. is not pairwise normal since {0} is T1-closed and N is T2-closed and a T2-open subset containing {0} intersects with any T1-open set containing N

Rare earth Dy activated Li3PO4:Dy phosphors for lyoluminescence dosimetry of ionizing radiations

     Rare earth Dy doped Li3PO4 phosphate based phosphors were prepared by high temperature solid state diffusion technique. The peak LL intensity initially increases with increasing mass of the sample, then tends to attain a saturation value for higher mass of the solute added to the solvent. Eaelier experiments on gamma irradiated crystals have proved that the light emission originates from the recombination of released F-centres with trapped holes (V2-centres) at the liquid-solid interface.In this paper lyoluminescence(LL) characteristics of Li3PO4:Dy phosphors have been reported . These LL characteristics of Li3PO4 phosphor may be useful for high radiation dosimetry using LL technique

Comparative study on mechanoluminescence of Eu2+ doped phosphate based phosphors.

Eu2+ doped phosphate based phosphors were prepared by solid state diffusion technique. The phosphors have simple glow curve with single peak It is clear that the ML intensity increases with increasing concentration of Eu, attained an optimum value for 1 mole % for Sr5(PO4)3Cl:Eu2+, and 2 mole% for Li3PO4:Eu2+ and LaPO4:Eu2+, then decreases with further increase in concentration of Eu. The trapping and detrapping of charge carriers in the material can be studied using ML. It is believed that in the dynamic process of loading, internal friction originating from defects activates holes released from traps and stimulates mechanoluminescience. This phosphor can be used in the dosimetry of ionizing radiations using mechanoluminescence

Corrections to "pairwise s-normal spaces" rev. colombiana mat. 26 (1992), 25-38

The following corrections are necessary in the paper:1. Example 2.1.1. is not pairwise normal since {0} is T1-closed and N is T2-closed and a T2-open subset containing {0} intersects with any T1-open set containing N

Economics of oyster culture

Economic analysis of any system of aquaculture practice aids not only to improvise management practices but also ensures profitability. Attention on return on investment has bsen rightly emphasized by MitcheU and Usry (1967), PiUay (1973) and IPFC (1975) to show that well planned and propsrly managed aquaculture ventures compare very favourably with similar other food production industries. Homell (1910) realising the edibility of the oyster meat and its nutritional value initiated efforts on oyster farming at Pulicat Lake and gave an approximate account of working expenses of a one ha. park

Coastal Aquaculture - Mussel farming; Progress and prospects

During the seventies, the Central Marine Fisheri^ lleseardi Institute gave a lead in researches on mariculture and has carved for itself a pioneering role in the R& D programmes of mariculture in the countiy which has been well recognised. Impressed by the outstanding contributions made during the decade, the infrastructure facilities built up and, above all, the scientific and techni<ial competence it has acquittdi jm UNDP/ICAR Centre of Advanced Studies in Mariculture has been instituted at the Central Marine Fisheries Research Institute since June 1979. The Centre aims at providing postgraduate education in the new discipline of Mariculture and improvmg the quality of research through doct(»ral and post-doctoral research programmes in identified areas. One of the priority areas of mariculture in India is mussel culture. Although considered a poor relation of the oyster in Europe, mussel has one of the highest potentials in India for increaang production of protein- rich sea food. Mussel gives the highest conversion of primary producera ^hytojrfankton) to human food and culture production in column waters enhances the yield several fold. India has a traditional sustenance fishery for the mmsels at a few centres but the scope for increasing natural production from the existing beds is rather limited