On the troll line investigations off Cochin during five fishing seasons. Pt. 2. Investigations during 1963-64 season

During this season the investigations were mainly directed towards elucidation of the selective action of trolling lures. Feather jigs, buffalo horn jigs, stainless steel jigs, Japanese whale bone jigs and plastic jigs were selected. Operations were carried out from Fisheries technology No. 5.

On the troll line investigations off Cochin during five fishing seasons. Pt. 3. Investigations during 1965-66 and 1966-67 seasons

During these two seasons investigations were carried out with a view to exploring the possibility of this operation on commercial basis and to study the effect of certain meteorological factors on catch.

On-line topographic analysis in the SEM

A novel method for on-line topographic analysis of rough surfaces in the SEM has been investigated. It utilises a digital minicomputer configured to act as a programmable scan generator and automatic focusing unit. The computer is coupled to the microscope through digital-to-analogue converters which enable it to generate ramp waveforms allowing the beam to be scanned over a small sub-region of the field under program control. A further digital-to-analogue converter regulates the current supply to the objective lens of the microscope. The video signal is sampled by means of an analogue-to-digital converter and the resultant binary code stored in the computer's memory as an array of numbers describing relative image intensity. Computations based on the intensity gradient of the image allow the objective lens current to be found for the in-focus condition, which may be related to the working distance through a previous calibration experiment. The sensitivity of the method for detecting small height changes is theoretically of the order of 1 μm. In practice the operator specifies features of interest by means of a mobile spot cursor injected into the SEM display screen, or he may scan the specimen at sub-regions corresponding to pre-determined points on a regular grid defined by him. The operation then proceeds under program control. | A novel method for on-line topographic analysis of rough surfaces in the SEM has been investigated. It utilizes a digital minicomputer configured to act as a programmable scan generator and automatic focusing unit. A further digital-to-analog converter regulates the current supply to the objective lens of the microscope. The video signal is sampled by means of an analog-to-digital converter and the resultant binary code stored in the computer's memory as an array of numbers describing relative image intensity. The sensitivity of the method for detecting small height changes is theroretically of the order of 1 mu m.

ON-LINE STEREO PROCESSING FOR THE SEM.

A convenient system for the rapid extraction of three dimensional information from pairs of SEM images has been constructed, eliminating the need for time-consuming photography. Results are produced in a digestable form. Distortions inherent in the SEM record display and in the photographic system are not relevant to the system described; only those arising within the column and stage need be considered.

Reproductive biology of the blue spot mullet Valamugil seheli (Forskal) from Mangalore Region, southwest coast of India

The blue spot mullet Valamugil seheli spawns once a year between August and February with peak spawning during October - November. Males attain maturity at 250.5 mm and females at 256.5 mm total length. Males outnumbered females in the commercial catches, although the sex-ratio (M:F=1:0.90) in the population showed no significant deviation. The fecundity of this species varied from 108378 to 910350 eggs with an average of 327944. Linear relationships were found between fish length, gonad weight and fecundity; and between fish length, fish weight and ovary weight.

Systematic study of the blue green algae of Ceylon kept at the herbarium of the Royal Botanical Gardens, Peradeniya

The collection of blue green algae kept at the herbarium of the Royal Botanical Gardens, Peradeniya, was collected by Ferguson more than 70 years ago. Since then many changes have taken place in the taxonomy of the blue green algae. West (1902), Lemmermann (1907), Wine (1915), Crow (1923), Bharadwaja (1934) and Holsinger (1935) had described some of the blue green algae of Ceylon. While examining the collections of blue green algae kept at the herbarium, the authors found that most of the identifications were incorrect and required revision. In the present paper 20 blue green algae are described. The classification and key to the species are based on the characters given by Desikachary (1959). Blue green algae are important to fisheries since Chanos larvae feed on them.

On the domain decomposition and transmission line modelling finite element method for time-domain induction motor analysis

This paper demonstrates how a finite element model which exploits domain decomposition is applied to the analysis of three-phase induction motors. It is shown that a significant gain in cpu time results when compared with standard finite element analysis. Aspects of the application of the method which are particular to induction motors are considered: the means of improving the convergence of the nonlinear finite element equations; the choice of symmetrical sub-domains; the modelling of relative movement; and the inclusion of periodic boundary conditions. © 1999 IEEE.

Application of domain decomposition and transmission line modelling techniques to 2D, time-domain, finite element problems

In this paper a recently published finite element method, which combines domain decomposition with a novel technique for solving nonlinear magnetostatic finite element problems is described. It is then shown how the method can be extended to, and optimised for, the solution of time-domain problems. © 1999 IEEE.

Bimesogenic liquid crystals: New materials for high performance flexoelectric and blue phase displays

In this paper we will describe new bimesogenic nematic liquid crystals that have high flexoelectro-optic coefficients (e/K),of the order of 1.5 CN 1 m-1, high switching angles, up to 100° and fast response times, of the order of 100μs or less. We will describe devices constructed, using the ULH texture that may be switched to the optimum angle of 45° for a birefringence based device with the fields of 4Vμm-1 over a wide temperature range. Such devices use an "in plane" optical switching mode, have gray scale capability and a wide viewing angle. We will describe devices using the USH or Grandjean texture that have an optically isotropic "field off" black state, uses "in plane" switching E fields, to give an induced birefringence phase device, with switching times of the order of 20μs. We will briefly describe new highly reflective Blue Phase devices stable over a 50V temperature range in which an electric field is used to switch the reflection from red to green, for example. Full RGB reflections may be obtained with switching times of a few milliseconds. Finally we will briefly mention potential applications including high efficiency RGB liquid crystal laser sources. © 2006 SID.

An analysis of the experimental pole and line fishery conducted around Sri Lanka by Nichiro Fishing Company of Japan

Under a joint agreement the Government of Sri Lanka and the Nichiro Fishing Company of Japan have undertaken an experimental pole and line fishery around Sri Lanka with a view to determining the feasibility of establishing a joint commercial venture. 3 Japanese vessels conducted trials during the period March 1973-October 1974. Details of the vessels and cruises are given. A variety of fish were tried as bait, and the selection of appropriate bait is discussed. Catches and catch and effort statistics are presented, with tables showing distribution of the tuna. The results of the trials were below expectations, and are in part attributed to bait availability, and unfavorable weather conditions. Seasonal variation of the type of fishery is suggested in order to take account of this, and it is concluded that a fishery based on 45/50 ft combined pole and line and drift net fishing vessels might prove feasible.

Studies on blue discolouration in canned body meat of crab (Scylla serrata)

Blue discolouration met with in the canned body meat of crab (Scylla serrata) was due to copper content exceeding 1.8 to 2.0 mg/100g on dry weight basis. Bleeding the cleaned carcasses of crab thoroughly in running water brought down the copper content below this level and blue discolouration prevented. Addition of copper ions to the thoroughly bled crab meat to raise the copper content above this level caused discolouration. The incidence of blue discolouration was independent of the freshness of the animals used. Citric acid in high concentration prevented blueing to some extent, but is not advisable as texture and flavour were adversely affected.