Post-harvest technology

In recent years great interest is envinced in several countries in the culture of molluscan shellfish. In the tropics favourable conditions exist for rapid growth and marketable oysters are obtained with in vir^n to twelve months. Investigations have been conducted at the Central Marine Fisheries Research institute and success has been achieved in perfecting the techniques of oyster culture in coastal waters (Nayar and Mahadevan, 1983). The awareness that shellfish have to be purified and rendered harmless goes back to the time of the Roman Empire. During the first century B.C. the Romans consumed cockles and oysters after treating them in tanks known as cockle washery (Yonge, 1962)

Larval rearing and production of spat of the oyster Crassostrea madrasensis (Preston) in an Experimental hatchery

The Indian backwater oyster, Crassostrea madrasensis, was spawned in the laboratory at Tuticorin. The larvae were reared and the spat settled in 15-20 days. Two species of jihytoflagellates, Isochrysis galbana and Pavlova sp. were isolated from the natural environment, cultured in mass scale and given as food throughout the larval period. Early stages of the development of fertilized egg, successive stages of developing larvae, and metamorphosis to the spat have been described. The methodology of the production of cultchless spat and rearing the post-set oysters are discussed

The edible oyster culture

In 1970s the CMFR Institute initiated oyster culture through rack and tray method. Large scale spat collection, preparation of spat collectors, season and seed availability were studied. In 1980, a hatchery was set up with annual production capacity of one million edible oyster seed and the techniques involved in hatchery system were standardized. The seed were supplied to other centres of this Institute and Gujarat Fisheries Department. The production rates for rack and tray, string and stake method were estimated as 120 t and 22 t respectively. As part of extension, one lab to land programme, 8 training programmes, one workshop and a summer insitute were conducted. Results of experimental oyster culture work carried out at Mandapam, Madras, Bheemunipatnam, Kakinada, Mulki, Dharmadam, Ashtamudi and Cochin backwaters are given. Rearing 600 strings in 0.04 ha at Ashtamudi and harvesting 2.5t oysters pointed out 44.8% return with estimated production of 80- 105t/ha. Further research priorities on oyster culture aspects are indicated

Indian edible oyster

In India pioneering attempts were made by James Hornell in 1910 in developing Oyster culture in the erstwhile Madras State. Scientific investigations were undertaken during early 70's by the Central Marine Fisheries Research Institute, at Tuticorin. The Institute has conducted R & D programmes on all aspects of Oyster farming during the last two decades, culminating in a wealth of informations on the technology of Oyster farming. The Brochure outlines various aspects of the technology of farming of the Indian Edible Oyster or the Indian Backwater Oyster Crasaostrea madrasensis (Preston} including information on biology, ecology and economics of Oyster farming

Experience paper on the operation of pilot project on oyster culture at Tuticorin

The technology of oyster culture was developed in India at the Central Marine Fisheries Research Institute. An experimental farm was established at Tuticorin bay in an area of 0.25 hectares. Different growout methods have been tried and it has been assessed that the shell string method could be practised with relatively low cost inputs with a production rate comparable to highly efficient systems such as rack and tray method or raft culture

Factors Affecting Habitat Occupancy of Tiger in the Terai ARC Landscape, India

Not availabl

Multi-Valued Majority Logic Circuits Using Spin Waves

With increasing data sets for processing, there is a requirement to build faster and smaller arithmetic circuits. One of the ways to improve the performance of higher order arithmetic units is to reduce the carry propagation levels. Multi-valued logic enables this by reducing the number of digits required to represent a range of numbers. Area reduction is also obtained through fewer operations and signals required to realise a function. Though theoretically multi-valued logic has these advantages, implementation of the multi-valued logic using CMOS has not been efficient. The main reason is because multi-valued logic is emulated in CMOS using binary switches. Two main approaches are followed in CMOS in implementing multi-valued logic using CMOS. Voltage mode logic, where the logic states are encoded using the node voltages suffer from low noise margins and limitation of radix due to the power supply. Current mode logic, where the branch currents are used to represent the logic levels suffer from high power consumption due to static current flow and requirement of restoration devices. The mindset of the post-CMOS approaches explored so far for multi-valued logic circuit design has been to replace the CMOS switches with their novel nano switches. Hence they too suffer from the same issues as CMOS implementation. Our value proposition is through the use of a truly multi-state device based on electron spin. Spin waves, which are a collection of electron spins of an atom enables multi-valued logic by allowing encoding information in the amplitude and phase of the wave.Another advantage of the spin wave fabric is that the computation is through wave propagation and interference which does not involve any movement of charge. This enables building low energy,smaller and faster multi-valued circuits. In this thesis, implementation of the basic building blocks of multi-valued logic using these novel spin wave based devices is shown. Building of arithmetic circuits like adders using these building blocks have also been demonstrated. To quantify the benefits of spin wave based multi-valued circuits, they are benchmarked with CMOS. For 32-bits, our projected comparisons show a 5X increased performance, 125X area improvement and 1717X power reduction for hexa-decimal spin wave based adders compared to binary CMOS. Similarly there is a 4X increase in performance of hexa-decimal SPWF multiplier compared to CMOS for 16 bits. Finally, we have implemented the I/O circuits for smooth interface between binary CMOS and multi-valued SPWF logic

Evaluation of DC-DC converter using renewable energy sources

This work analyses and evaluates the performance of renewable energy sources-based converters using Intelligent techniques. The objective of the research is to maintain the reliability of the converters such that it decreases the switching losses, high duty cycle and recycles the leakage energy. To accomplish the high output voltage gain converters are designed with different intelligent methods. Due to heavy demands, the cost of fossil fuel has gone up.so the need for the time is identifying and developing renewable energy sources along with developing new technologies for energy saving in renewable energy system to fight the issues plaguing the environment

Distribution and exploitation of oyster resources along the southeast and southwest coasts of India

The oysters are sedentary bivalve molluscs which are gregarious and found in aggregates attached by their right shell valve to hard substrata, forming oyster beds or oyster banks in varied environments, intertidal and subtidal zones in shallow coastal waters, bays, creeks, lagoons, backwaters and estuarine environment. In India, natural stocks of oysters are exploited on a small scale at a number of places as a subsistence fishery and oysters are not cultured commercially

Cephalopod resources in southeast and northeast coasts of India and Andaman - Nicobar waters

During 1988-'90, FORV Sagar Sampada has made 28 exclusive cruises to three regions in the Bay of Bengal covering different seasons of the year. Cephalopods formed one of the components of the demersal fishery resources of these regions, with the pelagic resources remaining insignificant. The commercially important neritic species of squids (Loligo duvauceli, Doryteuthis sibogae and Doryteuthis singhalensis), and cuttlefish (Sepia aculeata) were comparatively more in number and quantity than the species of oceanic squid Symplectoteuthis oualaniensis and other less important oceanic squids. The former groups of cephalopods were taken in demersal trawl and the latter in pelagic trawl. The distribution and relative abundance of various neritic and oceanic group of cephalopods by area and depth is given in the paper