Sabu, S; Boopendranath, M R(Cochin University of Science & Technology, August , 2008)
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Abstract:
Trawling, though an efficient method of fishing, is known to be one of the most non-selective methods of fish capture. The bulk of the wild caught penaeid shrimps landed in India are caught by trawling.In addition to shrimps, the trawler fleet also catches considerable amount of non-shrimp resources. The term bycatch means that portion of the catch other than target species caught while fishing, which are either retained or discarded. Bycatch discards is a serious problem leading to the depletion of the resources and negative impacts on biodiversity. In order to minimize this problem, trawling has to be made more selective by incorporating Bycatch Reduction Devices (BRDs). There are several advantages in using BRDs in shrimp trawling. BRDs reduce the negative impacts of shrimp trawling on marine community. Fishers could benefit economically from higher catch value due to improved catch quality, shorter sorting time, lower fuel costs, and longer tow duration. Adoption of BRDs by fishers would forestall criticism by conservation groups against trawling.
Description:
Faculty of Marine Sciences
COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
COCHIN-682 022
Jisha, C P; Dr.Kuriakose, V C(Cochin University of Science & Technology, March , 2008)
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Abstract:
This thesis deals with the study of light beam propagation through different
nonlinear media. Analytical and numerical methods are used to
show the formation of solitonS in these media. Basic experiments have
also been performed to show the formation of a self-written waveguide in a
photopolymer. The variational method is used for the analytical analysis
throughout the thesis. Numerical method based on the finite-difference forms of the original partial differential equation is used for the numerical
analysis.In Chapter 2, we have studied two kinds of solitons, the (2 + 1) D
spatial solitons and the (3 + l)D spatio-temporal solitons in a cubic-quintic
medium in the presence of multiphoton ionization.In Chapter 3, we have studied the evolution of light beam through a
different kind of nonlinear media, the photorcfractive polymer. We study
modulational instability and beam propagation through a photorefractive
polymer in the presence of absorption losses. The one dimensional beam
propagation through the nonlinear medium is studied using variational and
numerical methods. Stable soliton propagation is observed both analytically
and numerically.Chapter 4 deals with the study of modulational instability in a photorefractive
crystal in the presence of wave mixing effects. Modulational
instability in a photorefractive medium is studied in the presence of two
wave mixing. We then propose and derive a model for forward four wave
mixing in the photorefractive medium and investigate the modulational
instability induced by four wave mixing effects. By using the standard
linear stability analysis the instability gain is obtained.Chapter 5 deals with the study of self-written waveguides. Besides
the usual analytical analysis, basic experiments were done showing the
formation of self-written waveguide in a photopolymer system.
The formation of a directional coupler in a photopolymer system is
studied theoretically in Chapter 6. We propose and study, using the
variational approximation as well as numerical simulation, the evolution
of a probe beam through a directional coupler formed in a photopolymer system.
Description:
Department of Physics,
Cochin University of Science and Technology
This thesis deals with some aspects of the Physics of the early universe, like phase transitions, bubble nucleations and premodial density perturbations which lead to the formation structures in the universe. Quantum aspects of the gravitational interaction play an essential role in retical high-energy physics. The questions of the quantum gravity are naturally connected with early universe and Grand Unification Theories. In spite of numerous efforts, the various problems of quantum gravity remain still unsolved. In this condition, the consideration of different quantum gravity models is an inevitable stage to study the quantum aspects of gravitational interaction. The important role of gravitationally coupled scalar field in the physics of the early universe is discussed in this thesis. The study shows that the scalar-gravitational coupling and the scalar curvature did play a crucial role in determining the nature of phase transitions that took place in the early universe. The key idea in studying the formation structure in the universe is that of gravitational instability.
Bindhu, S G; Dr.Kuriakose, V C(Cochin University of Science and Technology, January , 2000)
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Abstract:
Nonlinearity is a charming element of nature and Nonlinear Science has now become one of the most important tools for the fundamental understanding of the nature. Solitons— solutions of a class of nonlinear partial differential equations — which propagate without spreading and having particle— like properties represent one of the most striking aspects of nonlinear phenomena. The study of wave propagation through nonlinear media has wide applications in different branches of physics.Different mathematical techniques have been introduced to study nonlinear systems. The thesis deals with the study of some of the aspects of electromagnetic wave propagation through nonlinear media, viz, plasma and ferromagnets, using reductive perturbation method. The thesis contains 6 chapters
Description:
Department
of Physics, Cochin University of Science and Technology
Mathew, E J; Dr.Mohammed Yusuff,K K(Cochin University of Science & Technology, November , 1990)
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Abstract:
The thesis deals with our studies on the synthesis and
elucidation of structure of some metal complexes of dithio
ligands, such as the dithiocarbamates, xanthates and
2-aminocyclopent-1-ene-1-dithiocarboxylate and its N-alkyl
derivatives.2-Aminocyclopent-1-ene-1-dithiocarboxylate (ACDA) is an
interesting ligand, because of its potential dual capability of
bonding between the metal and the ligand. Since the earlier
reports on the complexes of ACDA contain contradictory ideas on
the nature of its bonding, it was thought worthwhile to undertake
a detailed and systematic study of these type of complexes. As
the ACDA complexes have very low solubilities in solvents like
chloroform, we have used the isopropyl derivative of ACDA as the
ligand. The increased solubility of these complexes have made it
possible to investigate their NMR and solution electronic spectra.The complexes of this ligand have not yet been reported in the
literature.We have synthesised some new mixed ligand complexes of
dithiocarbamates by reacting bis(dithiocarbamato)-µ-dichloro
dicopper complexes (obtained by the reaction of mixed benzoic
dithiocarbamic anhydride and copper(II) chloride) with ACDA or its
N-alkyl derivatives.Interactions of metal halides with the mixed anhydrides
formed from benzoylchloride and xanthates have also been
investigated. Novel complexes of the type, [Cu2(RXant)CI]
(R=i-Bu, i-Pr, n-Bu or n-Pr)) have been isolated from the reaction
of copper(II) chloride and the mixed anhydride, and these
reactions appear to be like the clock reactions reported in the
literature.It also deal with the characterisation of
the complexes of the type [Hg(R2d t c )X] (X=Cl, Br or 1),[Cu3(R2dtc)6][Cu2Br6] and [Cu(R2dtc)Cl2](R2=Me2,Et2,Pip,Morph or Pyrr)respectively, synthesised by simple and novel routes,
different from those reported earlier.
Description:
Department of Applied Chemistry, Cochin
University of Science and Technology
Vineetha,C P; Mohammed Yusuff, K K(Department of Applied Chemistry, Faculty of Science, 2002)
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Abstract:
The thesis deals with the synthesis, characterization and catalytic activity studies of some new Fe (III), Co (II), Ni (II) and Cu (II) complexes of hydrazones and their zeolite encapsulated analogues. Hydrazones have diverse applications in biological, non-biological and biochemical front. During the present study three hydrazone types of ligands namely, acetylacetone- 2-hydroxyphenylhydrazone (APAcAc), acetoacetanilide- 2-hydroxyphenylhydrazone (APAcAcA) and acetoacetanilide-3,5-dihydro-2,4-dione pyrimidylhydrazone (AUAcAcA) were synthesized by diazotization of primary amine and coupling with compounds containing active methylene group. First part of the thesis deals with the synthesis of Fe, Co, Ni and Cu complexes using three hydrazone types of ligands are given. Details regarding the characterization of these complexes with a view to establishing the molecular structures are presented in this part. The other part contains the method of encapsulation of these complexes in zeolite cavities and their characterizations of the encapsulated metal species are described. A comparitive account of the catalytic activities of the pure and encapsulated complexes for cyclohexanol oxidation was also carried out.
Pearly Sebastian, Chittilappilly; Mohammed Yusuff, K K(Cochin University of Science and Technology, March , 2007)
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Abstract:
In the present study an attempt has been made to synthesize some simple complexes of
multidentate ligands. Analogous zeolite encapsulated complexes were also synthesized and
characterized. Immobilization on to polymer supports through covalent attachment is
expected to solve the problem of decomposition of many complexes during catalytic reaction.
Hence the work is also extended to the synthesis and characterization of some polymer
supported complexes of Schiff base Iigands. All the three types of synthesized complexes,
simple, zeolite encapsulated and polystyrene anchored, were subjected to catalytic activity
study towards catechol-oxidation reaction. A selected group of complexes were also screened
for their catalytic activity towards phenol-oxidation reaction. Biological screening of the
synthesized ligands and neat complexes were done with a view to establish the effect of
complexation on biological systems.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Mayadevi, S; Dr.Mohammed Yusuff,K K(Cochin University Of Science And Technology, August 6, 1997)
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Abstract:
This thesis deals with the synthesis, characterisation and
catalytic activity studies of some new transition metal complexes of the
Schiff bases, derived from quinoxaline—2—carboxaldehyde. The model
complexes derived from specially designed and synthesised Schiff bases
help us to understand the chemistry of biological systems. Schiff bases
derived from heterocyclic aldehydes like quinoxaline-2-carboxaldehyde
provide great structural diversity during complexation. The Schiff
bases synthesised in the present study ' are
quinoxaline—2—carboxa.lidene-2-aminophenol (QAP). quinoxaline—2carboxaldehyde
semicarbazone (QSC), quinoxaline-2—carboxalidene—o—
phenylenediamine (QOD) and quinoxaline-2-carboxalidene-2-furfurylamine
(QFA). The elucidation of the structure of these complexes is done
using conductance, magnetic susceptibility measurements. infrared,
UV—Vis and EPR spectral studies.
Description:
Dcpanmcm of Appiied Chemistry, Cochin Univenity of science and
Tochnology