| Abstract: | This thesis Entitled Studies on certain exploited marine Finfish Resources of india.Marine fish catch forecasting is short term or long term basis for purposes of explation and management. Among the short term forecasts, two approaches need serious consideration in India: 1. to improve the methods of understanding the influence of environmental characteristics on the abundance or availability of fish in different areas in different periods and to make the forecasts of the same, 2. to make analysis of time series catch data (ARIMA models) to make forecasts of catch in the next year or in a particular period during next year. There is some evidence of suitability of these approaches to Indian marine fisheries but attempts aiming at comprehensive studies should be made. In the area of long term forecasts, considerable work is done in India on single species assessments but in the context of multi species, multigear nature of Indian marine fisheries, assessments of all species together in a mixed fishery are urgently required for effective managements of fisheries. |
| Description: | School of Marine Scxience, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3153 |
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| Dyuthi-T1127.pdf | (11.70Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1221 |
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| Arun Shivnath Ninawe 1988.PDF | (549.5Kb) |
| Abstract: | The main goal of this thesis is to study the dynamics of Josephson junction system in the presence of an external rf-biasing.A system of two chaotically synchronized Josephson junction is studied.The change in the dynamics of the system in the presence of at phase difference between the applied fields is considered. Control of chaos is very important from an application point of view. The role Of phase difference in controlling chaos is discussed.An array of three Josephson junctions iS studied for the effect of phase difference on chaos and synchronization and the argument is extended for a system of N Josephson junctions. In the presence of a phase difference between the external fields, the system exhibits periodic behavior with a definite phase relationship between all the three junctions.Itdeals with an array of three Josephson junctions with a time delay in the coupling term. It is observed that only the outer systems synchronize while the middle system remain uncorrelated with t-he other two. The effect of phase difference between the applied fields and time-delay on system dynamics and synchronization is also studied. We study the influence of an applied ac biasing on a serniannular Josephson junction. It is found the magnetic field along with the biasing induces creation and annihilation of fluxons in the junction. The I-V characteristics of the junction is studied by considering the surface loss term also in the model equation. The system is found to exhibit chaotic behavior in the presence of ac biasing. |
| Description: | Department of Physics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2904 |
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| Dyuthi-T0900.pdf | (4.928Mb) |
| Abstract: | Ion-exchange chromatography has emerged as a practical and rapid method of separation and analysis. A review of literature on chelating resins reveals that eventhough investigations on highly selective resins are intensively pursued from early 1940s, such resins are still insufficiently used in analytical chemistry and process technology. This is mainly due to the complexity of their synthesis and high cost. In this context, it is worthwhile to develop novel chelating resins which are specific or at least selective towards a group of metal ions. Synthesis, characterization and analytical applications of two such resins are presented in this thesis. |
| Description: | Department of Applied Chemistry, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3614 |
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| Dyuthi-T1572.pdf | (4.488Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1018 |
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| Lucy Joseph 1988.pdf | (259.8Kb) |
| Abstract: | Chemical bath deposition (CBD)is one of the simplest, very convient and probably the cheapest method for thin film preparation. Photovoltaic is the cleanest and the most efficient mode of conversion of energy to electrical power. Silicon is the most popular material in this field. The present study on chemical bath deposited semiconducting copper selenide and iron sulfide thin films useful for photovoltaic applications. Semiconducting thin films prepared by chemical deposition find applications as photo detectors, solar control coatings and solar cells. Copper selenide is a p-type semiconductor that finds application in photovolitics. Several heterojunction systems such as Cu2-xSe/ZnSe (for injection electro luminescence), Cu2Se/AgInSe2 and Cu2Se/Si (for photodiodes), Cu2-xSe/CdS, Cu2-xSe/CdSe, CuxSe/InP and Cu2-xSe/Si for solar cells are reported. A maximum efficiency of 8.3% was achieved for the Cu2-xSe/Si cell, various preparation techniques are used for copper selenide like vacuum evaporation, direct reaction, electrodeposition and CBD. Instability of the as-prepared films was investigation and is accounted as mainly due to deviation from stoichiometry and the formation of iron oxide impurity. A sulphur annealing chamber was designed and fabricated for this work. These samples wee also analysed using optical absorption technique, XPS (X-ray Photoelectron Spectroscopy) and XRD.(X-Ray Diffraction).The pyrite films obtained by CBD technique showed amorphous nature and the electrical studies carried out showed the films to be of high resistive nature. Future work possible in the material of iron pyrite includes sulphur annealing of the non-stochiometric iron pyrite CBD thin films in the absence of atmospheric oxygen |
| URI: | http://dyuthi.cusat.ac.in/purl/941 |
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| Dyuthi-T0021.pdf | (10.53Mb) |
| Abstract: | The thesis is proposed to study the occurrence and distribution of chitinoclasts in water, sediment and fauna as related to site characteristics such as temperature, salinity, depth of water, pH, etc. Since no information is available on the chitinolytic properties of coastal strains, it is also proposed to study the chitinolytic activity of the bacterial isolates in relation to various environmental conditions. It is also planned to work out the taxonomy of some of the representative isolates and certain kinetic properties of their chitinases. It is expected that the results of the study would yield a comprehensive information-on the chitinoclastic bacteria in the southern coastal zone of west coast of India. |
| Description: | Department Of Marine Sciences,Cochin University Of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3482 |
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| Dyuthi-T1428.pdf | (7.069Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1157 |
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| Ivy Thomas 1984.PDF | (398.6Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/2198 |
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| Dyuthi-T0549.pdf | (3.278Mb) |
| Description: | Department of Mathematics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2349 |
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| Dyuthi-T0621.pdf | (503.3Kb) |
| Abstract: | In India much work has been done on different aspects of quality of processed fish and fishery products (Pillai et al., 1965; Iyer and Chaudhuri, 1966; Iyer et al., 1966; Sreenivasan and Joseph, 1966; Pillai and Rao, 1969; Mathen et al., 1975; Valsan et al., 1985) and standards have been formulated for almost all the fishery products. Quality standards for fresh fish cover only a few fish species available in the markets. For the formulation and recommendation of quality standards for fish and fishery products for domestic trade detailed background informations are necessary. Khot et al., (1982), Valsan et al. J (1985) and Iyer et al. (1986) have reported on the bacterial flora of sea foods at retail level in Bombay. Cochin is a major fish landing centre of the south west coast of India, and an average of 25,000. tonnes of fish/shell fish are landed annually at this harbour which is about 10 percent of the total catch of fish in Kerala (Lakshmanan -et -al., 1984). All the varieties of marine, brackish water and fresh water fishes are available in Cochln throughout the year for catering to Its cosmopolitan. population and informations regarding their bacteriological quality are scanty. Hence the present study was undertaken to investigate the bacteriological quality of fish and fishery products available in the markets and cold storages situated in and around Cochin meant for internal consumption. |
| Description: | Central Institute of Fisheries Technology, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3410 |
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| Dyuthi-T1386.pdf | (3.128Mb) |
| Description: | Theory Division Department of Physics |
| URI: | http://dyuthi.cusat.ac.in/purl/5016 |
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| Dyuthi-T2083.pdf | (3.615Mb) |
| Abstract: | The primary aim of this work has been to develop conductive silicone and nitrile rubbers, which are extensively used for making conductive pads in telephone sets, calculators and other applications. Another objective of the work has been to synthesise and characterize novel conducting polymers based on glyoxal and paraphenylenediamine- poly(p-phenylenediazomethine. Conducting polymer matrices were developed from polymer blends such as poly(pphenylenediazomethine), polyethylene, PVC and silica and their properties were studied. |
| Description: | Department of Polymer Science and Rubber Technology,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2201 |
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| Dyuthi-T0558.pdf | (5.380Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1601 |
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| Dyuthi-T0022.pdf | (3.541Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1659 |
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| Dyuthi-T0023.pdf | (3.315Mb) |
| Abstract: | The present study of the parasitic copepods gives the taxonomic description of thirty one species of parasites collected from various elasmobranch fishes of Kerala coast. Copepods parasitic on fishes include three sub orders, viz. poecilostomatoida, cyclopoida and siphonostomatoida. Parasitic copepods of elasmobranch fishes for the present study were collected from different fish landing centres of Kerala and by undertaking regular fishing trips. The collected parasites are identified to the species level and described. It is found that out of thirty one species, fifteen are new to science. They belong to the genera viz. Nothobomolochus Vervoot, 1962, Caligus Muller, 1785, Alebion, Kroyer, 1863, Gloipotes Steenstrup and Lutken, 1861, Pandarus Leach,1819, Perissopus Steenstrup and Lutken, 1861, Echthrogaleus Steenstrup and Lutken, 1861 and Kroyeria van Beneden, 1853. Fifteen new host records were reported. Two genera viz. Echthrogaleus and Entepherus were reported for first time from Indian waters. A new genus called Penicillus was erected. The general observations made during this study revealed certain interesting aspects of host-parasite relationship, host specificity, site specificity, adaptive modifications and geographical distribution. |
| Description: | Department of Industrial Fisheries, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2092 |
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| Dyuthi-T0459.pdf | (3.429Mb) |
| Abstract: | The main objectives of the study are: To study the seasonal distribution of copepods with special reference to their qualitative and quantitative distribution, with notes on biodiversity in the Andaman Sea and the Bay of Bengal. To study the spatial and temporal distribution of copepods in the Andaman Sea and the Bay of Bengal.To understand the hydrography and the environmental characteristics of the Andaman Sea and the Bay of Bengal and their role in the distribution and biomass of copepods.To study the vertical migration/diurnal migration of the copepods. To study the difference between the coastal and oceanic composition of copepods in the study area and the factors responsible for it. |
| Description: | National Institute of Oceanography, Regional Centre, Kochi |
| URI: | http://dyuthi.cusat.ac.in/purl/4629 |
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| Dyuthi-T1821.pdf | (4.688Mb) |
| Abstract: | Cosmology deals with the studies on the structure and evolution of the universe. The model of the universe formulated by Friedmann, Lemaitre, Robertson andWalker known as the standard model (FLRW model) of the universe, which is based on the Einstein's theory of gravity, turned out to be the accepted model because of the various observational supports. The major observational supports to this model are the explanation for the Hubble's law, primordial nucleosynthesis, microwave back ground radiation etc. Recent observations on Type Ia supernovae by teams led by S Perlmutter, Brian P Schmidt and Adam G Riess led to the discovery that the present universe is expanding in an accelerated manner. The exotic form of matter which causes the acceleration is termed as dark energy which produce negative pressure. Understanding the nature and evolution of dark energy is a challenge for the cosmologists. In addition to the evidences from supernovae, the anisotropy in CMBR spectra, large scale structures and Baryon acoustic oscillations are also supporting the discovery. To explain dark energy, various theoretical models have been proposed. One such model is the CDM model, in which the universe is assumed to be composed of dark energy and dark matter. In this model, Einstein's cosmological constant is considered as dark energy. It has a constant equation of state; ! = p = 1: The model predicts the values of cosmological parameters such as the Hubble parameter, transition redshift and present deceleration parameter, having a very good agreement with the observational constraints. But this model has two major aws, which are: 1. Cosmological constant problem:- Theoretically predicted value of dark energy density as the vacuum constant is, 1074GeV 4; while the observed value is 1047GeV 4: The predicted value is greater than the observed value by 120 orders of magnitude. This discrepancy between the theoretical and observational values is known as the cosmological constant problem. 2. Cosmological coincidence problem:- Energy densities of dark energy and dark matter are found to be of the same order even though their evolutionary nature are di erent. This is known as the coincidence problem which is not explained by the CDM model. These led to the proposals of dynamical dark energy models by considering that the equation of state parameter is evolving with the expanding universe. Scalar models of dark energy such as Quintessence, K-essence, Phantom model, Chaplygin gas model and holographicdark energy model are examples of dynamic dark energy models. Holographic dark energy model is based on the holographic principle developed by Susskind and 't Hooft. The principle says that the degrees of freedom of a system resides on its surface rather than in its volume. The total energy inside a region of size L must not exceed the mass of a black hole of the same size. The holographic dark energy density can then be formulated as, = 3c2M2 plL2 (1) where 3c2 is a numerical constant, M2 pl = 8 G is the reduced Planck mass. Possible choices for L; the IR cut-o , are Hubble horizon, particle horizon and event horizon. The choices for the IR cut-o whether it be Hubble horizon or particle horizon will not support an accelerating universe, while the third choice, the event horizon, violates causality. Another alternative for the IR cut-o is the Ricci scalar, which was rst introduced by Gao et al. Later modi ed holographic Ricci dark energy was proposed by Granda and Oliveros. In the present thesis, the modi ed Ricci dark energy is studied by considering its interaction with the dark matter present in the universe. Owing to the lack of knowledge about the microscopic origin of such an interaction, phenomenological interaction forms of nongravitational nature is assumed. |
| URI: | http://dyuthi.cusat.ac.in/purl/5163 |
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| Dyuthi-T2197.pdf | (2.575Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1158 |
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| Radha Devi A 1984.PDF | (328.6Kb) |
| Abstract: | Cumacea plays an important role in the marine environment as food for man and comercially important species of fishes . Hence it is desirable to have a better knowledge of the taxonomy, ecology, biology and distribution of the various species of Cumacea. The present work is directed towards the study of the above aspects |
| Description: | School Of Marine Sciences,Cochin University Of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3533 |
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| Dyuthi-T1464.pdf | (7.786Mb) |
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