Vijayakumar,A; Dr.Thrivikraman, T(Cochin University of Science and Technology, July , 1985)
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Abstract:
This thesis is an attempt to initiate the development of a discrete geometry of the discrete
plane H = {(qmxo,qnyo); m,n e Z - the set of integers}, where q s (0,1) is fixed and (xO,yO) is a fixed point in the first quadrant of the complex plane, xo,y0 ¢ 0. The discrete plane was first considered by Harman in 1972, to evolve a discrete analytic function theory for geometric difference functions. We shall mention briefly, through various sections, the principle
of discretization, an outline of discrete a alytic function theory, the concept of geometry of space and also summary of work done in this thesis
Description:
Department
of Mathematics and Statistics,Cochin University of Science & Technology
Ramachandra, Sharma N; Dr.Madhavan Pillai, P(Cochin University of Science And Technology, March , 1988)
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Abstract:
Strychnine is the major alkaloid present in the seeds of _Strychnos, nuxvomica tree which grow naturally in this area. Strychnine has a very complex chemical structure and is known to stimulate all portions of the central nervous system with preference to the spinal cord. However, it is a powerful convulsant and death results from asphyxia. Consequently strychnine has no therapeutic application in the western system of medicine at present. The objective of this work, therefore, was to convert strychnine by microbial transformation into a product having more desirable pharmacological properties so that this locally available natural product may find some use in the preparation of a therapeutic agent.
Description:
Department of applied chemistry, Cochin University of Science And Technology
Geetha, S; Dr.Jathavedan, M(Cochin University of Science and Technology, July , 1994)
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Abstract:
The study of stability problems is relevant to the study of structure of a physical system. It 1S particularly important when it is not possible to probe into its interior and obtain information on its structure by a direct method. The thesis states about stability theory that has become of dominant importance in the study of dynamical systems. and has many applications in
basic fields like meteorology, oceanography, astrophysics and geophysics- to mention few of them. The definition of stability was found useful 1n many situations, but inadequate in many others so that a host of other important concepts have been introduced in past many years which
are more or less related to the first definition and to the common sense meaning of stability.
In recent years the theoretical developments in the studies of instabilities and turbulence have been as profound as the developments in experimental methods. The study here
Points to a new direction for stability studies based on Lagrangian formulation instead
of the Hamiltonian formulation used by other authors.
Description:
Division of Mathematics,
School of Mathematical Sciences, Cochin University of Science and
Technology
Sreedharan Nair, M N; Dr.Babu, Joseph K(Cochin University of Science and Technology, November 2, 1981)
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Abstract:
This thesis is devoted to theoretical studies on the properties of hadrons on the basis of bag models. It contains some applications of the traditional.HIT bag model to the spectroscopy and decay of hadrons. The inadequacies of the model are brought out and a new version of the model, called the variable pressure bag model, is developed. Some of the Phenomenological applications of this model are discussed and the predictions are compared with experiment.
Description:
Department of Physics, Cochin University of Science & Technology
Dhanya, T P; Dr.Sugunan, S(Cochin University Of Science And Technology, November 7, 2012)
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Abstract:
Semiconductor photocatalysis has received much attention during last
three decades as a promising solution for both energy generation and
environmental problems. Heterogeneous photocatalytic oxidation allows the
degradation of organic compounds into carbon dioxide and water in the
presence of a semiconductor catalyst and UV light source. The •OH radicals
formed during the photocatalytic processes are powerful oxidizing agents and
can mineralise a number of organic contaminants. Titanium dioxide (TiO2),
due to its chemical stability, non-toxicity and low cost represents one of the
most efficient photocatalyst. However, only the ultraviolet fraction of the solar
radiation is active in the photoexcitation processes using pure TiO2 and
although, TiO2 can treat a wide range of organic pollutants the effectiveness of
the process for pollution abatement is still low.
A more effective and efficient catalyst therefore must be formulated.
Doping of TiO2 was considered with the aim of improving photocatalytic
properties.
In this study TiO2 catalyst was prepared using the sol-gel method. Metal
and nonmetal doped TiO2 catalysts were prepared. The photoactivity of the
catalyst was evaluated by the photodegradation of different dyes and pesticides
in aqueous solution.
High photocatalytic degradation of all the pollutants was observed with
doped TiO2. Structural and optical properties of the catalysts were characterized
using XRD, BET surface area, UV-Vis. DRS, CHNS analysis, SEM, EDX, TEM,
XPS, FTIR and TG. All the catalysts showed the anatase phase. The presence of
dopants shifts the absorption of TiO2 into the visible region indicating the
possibility of using visible light for photocatalytic processes.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Ambili, V K; Dr.Sugunan, S(Cochin University of Science and Technology, April , 2011)
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Abstract:
To meet the challenges related to the chemical industry,development of efficient catalysts is necessary.The mesoporous materials like SBA-15 are considered as good catalyst candidates of 21st century.SBA-15 mesoporous materials are catalytically inactive,but allow the dispersion of catalytically active phases into the framework.So these materials can be considered as an interesting alternative for preparing catalytically active metal nanoparticles in-situ into it.In the present work various transition metals are incorporated to improve the catalytic activity of SBA-15 material.The fundamental aspects of the preparation,characterization and the activity studies are briefly viewed in this thesis. Systematic investigation of the physico-chemical properties and catalytic activity studies of the prepared materials were carried out and presented in this Study.
Description:
Department of Applied Chemistry,Cochin University of Science and Technology
Joyes, Jacob; Dr.Sugunan, S(Cochin University of Science and Technology, December 14, 2009)
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Abstract:
Scientists throughout the world are in search of a better methodology to reduce the use of environmentally hazardous chemicals common in industries .A significant contribution in this field is given by different redox catalysts in oxidation reactions. The oxidation of organic substrates represents one of the most important industrial chemical reactions, explaining the significant efforts invested in the research and development of new heterogeneous catalysts with increased activities and selectivities in these type reactions[l-4|. Hence liquid phase reactions like epoxidation of cylcohexene and hydroxylation of phenol were carried out with a new outlook in the challenge using CeO2/TiO;; and CuO/TiO2 catalysts denoted as TiO2-Ce as TiO2-Cu respectively in this work. Also different wt% of metals incorporated titania catalysts like 3, 6, 9 wt% CeO2/TiO; and CuO/TiO;were subjected to the present study .The interaction between metal oxides and the oxide supports have attracted much attention because of the wide applications of supported metal oxide systems[7,8]. It is well known that supported oxides of transition metals are widely used as catalysts for various reactions. Titania as well its metal modified catalysts systems afford high activity and selectivity in the liquid phase epoxidation of cyclohexene[9]. Cyclohexene epoxide is obtained as the major product during the reaction with small amounts of allylic substitution products.This chapter gives an idea about the liquid phase oxidation reactions like epoxidation of cylcohexene and hydroxylation of phenol in which many industrially important products are formed. Here discusses about the redox properties of the ceria and copper incorporated titania catalysts.The epoxidation of cyclohcxene is carried out efficiently over the prepared systems with the selective formation of cyclohexane epoxide. This reaction hints that it might be possible to create cleaner nylon chemistry. The total acidity of the prepared systems plays an important role in determining the catalytic activity in the dehydrogenation of cyclohexane and cyclohexene. The total acidity of the prepared systems plays an important role in determining the catalytic activity in the dehydrogenation of cyclohexane and cyclohexene.
Description:
Department of Applied Chemistry, Cochin University of Science and Technology
Suja, Haridas; Dr.Sugunan, S(Cochin University of Science & Technology, January , 2002)
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Abstract:
The present project was a systematic investigation of the
physico-chemical properties and catalytic activity of some transition metal promoted
sulphated zirconia systems. The characterisation and catalytic activity results were
compared with that of pure Zr02 and simple sulphated zirconia systems. Sulphated
zirconia samples were prepared by a controlled impregnation technique. In the case of
metal incorporated systems, a single step impregnation was carried out using required
amounts of sulphuric acid and metal salt solutions. As a preliminary step, optimisation of
calcination temperature and sulphate content was achieved. For further studies, the
optimised sulphate loading of 10 ml per gram of hydrous zirconium oxide and a
calcination temperature of 700°C was employed. Metal incorporation had a positive
influence on the physico-chemical properties. Vapour phase cumene conversion served as
a test reaction for acidity. Some industrially important reactions like Friedel-Crafts
reaction, phenol hydroxylation, nitration, etc. were selected to test the catalytic activity of
the prepared systems.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Sreeja Rani, K; Prathapan,S; Sugunan, S(Department of Applied Chemistry,Faculty of Science, 2002)
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Abstract:
Catalysis is an essential technology in manufacturing industries. The investigation based on supported vanadia catalysts and it’s sulfated analogues. Vanadia is a transition metal oxide and is used in oxidation reactions in chemical industry. It is more active and selective catalysts on suitable supports. The work deals with preparation of vanadia incorporated tin oxide and zirconia systems by wet impregnation. Physico-chemical characterization using instrumental techniques like BET etc. The surface acidic properties were determined by the ammonia TPD studies, Perylene absorption studies and Cumene conversion reaction. The catalytic activities of the prepared systems are tested by Friedel-Crafts benzylation of arenes and Bechmann rearrangement of Cyclohexanol oxime. Here the rector reactions are relatively rare. So to test the application of the catalyst systems for the selective oxidation of cyclohexanol to cyclohexanone and finally evaluate the catalytic activity of the systems for the vapour phase oxidative dehydrogenation of Ethylbenzene, which leads to the formation of
Industrially important compound ‘styrene’ is another objective of this work
Chitra, R Nayak; Dr.Kuriakose, V C(Cochin University of Science and Technology, October , 2008)
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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
Lucy,Joseph; Dr.Sivasankara Pillai, V N(Cochin University Of Science And Technology, December 10, 1987)
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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
Lakshmi,M; Sudha Kartha, C(Department of Physics, 2001)
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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