Manjusha, S; Dr.Sarita,Bhat G(Cochin University of Science and Technology, December , 2006)
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Abstract:
While the seriousness of the problem of antibiotic resistance is now
recognized, the complex web of resistance linking humans, animals, and the
environment is getting realized. More often, antibiotics are used as a preventive
measure against diseases. Antibiotic use for agriculture leads to the increased
resistance in the environment since antibiotics are inevitable element during
agriculture/aquaculture and antibiotic residues are excreted as waste that is frequently
spread onto farmland as organic fertilizer. Fecal bacteria survive long periods in the
environment and spread through runoff into groundwater, rivers, and marine
ecosystems.However, horizontal gene transfer occurs in the animals and guts of humans and
in a variety of ecosystems, creating a pool of resistance in the rice fields and open
waters. Even if people are not in direct contact with resistant disease through food
animals, there are chances of contact with resistant fecal pathogens from the
environment. Additionally, pathogens that are autochthonous to the environment can
acquire resistance genes from the environment. Our study revealed that autochthonous
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bacteria Vibrio spp gained antibiotic resistance in the environment. Further, it was
evident that horizontal gene transfer occurs in Vibrio by means of plasmids, which
further augments the gravity of the problem. Non-pathogenic bacteria may also
acquire resistance genes and serve as a continuing source of resistance for other
bacteria, both in the environment, and in the human gut. As the effectiveness of
antibiotics for medical applications decline, the indiscriminate use of in aquaculture
and in humans can have disastrous conditions in future due to horizontal gene transfer
and the spread of resistant organisms: We must recognize and deal with the threat
posed by overuse of antibiotics.
Description:
Department of Biotechnology,
Cochin University of Science and Technology
Joshy, N V; Dr.Jayaraj, M K(Cochin University of Science & Technology, June , 2008)
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Abstract:
The main objective of the present study is to understand different mechanisms
involved in the production and evolution of plasma by the pulsed laser ablation
and radio frequency magnetron sputtering. These two methods are of particular
interest, as these are well accomplished methods used for surface coatings,
nanostructure fabrications and other thin film devices fabrications. Material
science researchers all over the world are involved in the development of
devices based on transparent conducting oxide (TCO) thin films. Our laboratory
has been involved in the development of TCO devices like thin film diodes
using zinc oxide (ZnO) and zinc magnesium oxide (ZnMgO), thin film
transistors (TFT's) using zinc indium oxide and zinc indium tin oxide, and some
electroluminescent (EL) devices by pulsed laser ablation and RF magnetron
sputtering.In contrast to the extensive literature relating to pure ZnO and other thin films
produced by various deposition techniques, there appears to have been relatively
little effort directed towards the characterization of plasmas from which such
films are produced. The knowledge of plasma dynamics corresponding to the
variations in the input parameters of ablation and sputtering, with the kind of
laser/magnetron used for the generation of plasma, is limited. To improve the
quality of the deposited films for desired application, a sound understanding of
the plume dynamics, physical and chemical properties of the species in the
plume is required. Generally, there is a correlation between the plume dynamics
and the structural properties of the films deposited. Thus the study of the
characteristics of the plume contributes to a better understanding and control of
the deposition process itself. The hydrodynamic expansion of the plume, the composition, and SIze distribution of clusters depend not only on initial
conditions of plasma production but also on the ambient gas composition and
pressure. The growth and deposition of the films are detennined by the
thermodynamic parameters of the target material and initial conditions such as
electron temperature and density of the plasma.For optimizing the deposition parameters of various films (stoichiometric or
otherwise), in-situ or ex-situ monitoring of plasma plume dynamics become
necessary for the purpose of repeatability and reliability. With this in mind, the
plume dynamics and compositions of laser ablated and RF magnetron sputtered
zinc oxide plasmas have been investigated. The plasmas studied were produced
at conditions employed typically for the deposition of ZnO films by both
methods. Apart from this two component ZnO plasma, a multi-component
material (lead zirconium titanate) was ablated and plasma was characterized.
Description:
Department of Physics,
Cochin University of Science and Technology
Sasi Kumar, P R; Dr.Nampoori,V P N(Cochin University of Science and Technology, August 20, 1994)
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Abstract:
Electrical gas discharges have been the subject of numerous
investigations from the last century due to their growing
interest in technological and fundamental applications.
Absorption of electromagnetic radiation by a gas discharge result
into a change in electrical impedance due to a significant
perturbations in the steady state population of excited levels
and the degree of ionization. This change in impedance produced
by resonant absorption of radiation is known as optogalvanic COG)
effect. where as that is produced by injecting electrons in to
the discharge by photoelectric emission is usually known as
photoemission optogalvanic (FOG) effect. With the development of
lasers and sophisticated electronic equipment. these effects have
established their importance in analytical and spectroscopic
measurements. The present thesis deals with the work carried out
by the author in the field optogalvanic effect during the past
few years at the Department of Physics in Cochin University of
Science| and "Fechnology. The results and the observation are
summarized in nine chapters and the references to the literature
is made at the end of each chapter
Description:
Department of Physics. Cochin University of Science and
Technology
Pushpakumari,K N; Dr.Paul, Vatakencherry A(Cochin University of Science and Technology, September , 1987)
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Abstract:
The thesis deals with the different properties and characteristics of oil of lemon grass.. The oil of lemongrass (Cymbopogon flexuosus) is one of the most important essential oils. It will continue to be one of the "big ten" of our essential oils1. Lemongrass oil is obtained from certain species of grasses of the genus cymbopogon. The genus consists of about 80 species, 10 to 12 of which are known to occur in India. Lemongrass is a stoloniferous plant. The plant grows wild in many tropical andsemitropical parts of Asia, Africa and in parts of Central America and South America. For the extraction of the oil however only cultivated lemongrass is employed. The trade distinguishes two Principal types of lemongrass oil, viz. the East Indian Oil and West Indian Oil. There was much confusion, years ago, about the taxonomy of the plants which yield theEast Indian and West Indian types of lemongrass oil, however Stapf2 ended the long controversy of identifying the plant yielding the East Indian type oil as Cymbopogon flexuosus (D.C.) Stapf and the plant yielding the West Indian type oil as Cymbopogon citrates (D.C.) stapf. The 2 plants have_been named variously also Andropogon nardus var. Flexuosus Hack or A. citratus D.C. respectively
Description:
Department of Applied Chemistry, Cochin
University of Science and Technology
Ajithkumar, C M; Dr.Babu, Joseph K(Cochin University of Science and Technology, 1986)
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Abstract:
In 1931 Dirac studied the motion of an electron in the field of a magnetic monopole and found that the quantization of electric charge can be explained by postulating the mere existence of a magnetic monopole. Since 1974 there has been a resurgence of interest in magnetic monopole due to the work of ‘t’ Hooft and Polyakov who independently observed that monopoles can exist as finite energy topologically stable solutions to certain spontaneously broken gauge theories. The thesis, “Studies on Magnetic Monopole Solutions of Non-abelian Gauge Theories and Related Problems”, reports a systematic investigation of classical solutions of non-abelian gauge theories with special emphasis on magnetic monopoles and dyons which possess both electric and magnetic charges. The formation of bound states of a dyon with fermions and bosons is also studied in detail.
The thesis opens with an account of a new derivation of a relationship between the magnetic charge of a dyon and the topology of the gauge fields associated with it. Although this formula has been reported earlier in the literature, the present method has two distinct advantages. In the first place, it does not depend either on the mechanism of symmetry breaking or on the nature of the residual symmetry group. Secondly, the results can be generalized to finite temperature monopoles.
Description:
Department of Physics, Cochin University of Science and Technology
Nancy, Mathew; Dr.Prathapachandra Kurup,M R(Cochin University of Science and Technology, June , 2011)
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Abstract:
Studies on transition metal complexes have achieved a great interest due to their versatile applications.The convenient route for synthesis,the nature of ligands and stability of metal complexes has significant contributions in their applications in medicine,biology,catalysis and photonics.The present work deals wth the synthesis and characterization of metal complexes of some tridentate acylhydrazones .Hydrazones are promising ligands in coordination chemistry with interesting binding modes and applications.The acylhydrazones chosen for the current study are capable of forming complexes in different forms through tautomerism.
Description:
Department of Applied Chemistry,Cochin University of Science and Technology
Paul,C M; Dr.Girijavallabhan,C P(Cochin University of Science And Technology, April , 1982)
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Abstract:
The major objective of the thesis is essentially to evolve and apply certain computational procedures to evaluate the structure and properties of some simple polyatomic molecules
making use of spectroscopic data available from the literature. It must be said that though there is dwindling interest in recent times in such analyses, there exists tremendous scope
and utility for attempting such calculations as the precision and reliability of'experimental techniques in spectroscopy have increased vastly due to enormous sophistication of the instruments used for these measurements. In the present thesis an attempt is made to extract maximum amount of information regarding the geometrical structure and interatmic forces of simple molecules from the experimental data on microwave and infrared spectra of
these molecules
Description:
Department of physics, Cochin University of Science And Technology
Mercy, Mani P; Dr.Ramachandra Kaimal, M(Cochin University of Science And Technology, June , 1988)
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Abstract:
The nonlinear dynamics of certain important reaction systems are discussed and analysed in this thesis. The interest in the theoretical and the experimental studies of chemical reactions showing oscillatory dynamics and associated properties is increasing very rapidly. An attempt is made to study some nonlinear phenomena exhibited by the well known chemical oscillator, the BelousovZhabotinskii reaction whose mathematical properties are much in common with the properties of biological oscillators. While extremely complex, this reaction is still much simpler
than biological systems at least from the modelling point of view. A suitable model [19] for the system is analysed and the researcher has studied the limit cycle behaviour of the system, for
different values of the stoichiometric parameter f, by keeping the value of the reaction rate (k6) fixed at k6 = l. The more complicated three-variable model is stiff in nature.
Description:
Department of mathematics and statistics, Cochin University of Science And Technology
Radhakrishnan, R; Dr. Ramesh Babu, T(Cochin University of Science and Technology, July , 2008)
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Abstract:
In the present thesis we have formulated the Dalgarno-Lewis procedure
for two-and three-photon processes and an elegant alternate expressions
are derived. Starting from a brief review on various multiphoton processes
we have discussed the difficulties coming in the perturbative treatment
of multiphoton processes. A small discussion on various available methods
for studying multiphoton processes are presented in chapter 2. These
theoretical treatments mainly concentrate on the evaluation of the higher
order matrix elements coming in the perturbation theory. In chapter 3 we
have described the use of Dalgarno-Lewis procedure and its implimentation on second order matrix elements. The analytical expressions for twophoton
transition amplitude, two-photon ionization cross section, dipole
dynamic polarizability and Kramers-Heiseberg are obtained in a unified
manner. Fourth chapter is an extension of the implicit summation technique
presented in chapter 3. We have clearly mentioned the advantage of
our method, especially the analytical continuation of the relevant expressions
suited for various values of radiation frequency which is also used for
efficient numerical analysis.
A possible extension of the work is to study various multiphoton processcs
from the stark shifted first excited states of hydrogen atom. We
can also extend this procedure for studying multiphoton processes in alkali
atoms as well as Rydberg atoms. Also, instead of going for analytical expressions,
one can try a complete numerical evaluation of the higher order
matrix elements using this procedure.
Description:
Department of Physics,
Cochin University of Science and Technology
Reghunath, A T; Dr.Nampoori,V P N(Cochin University of Science And Technology, November , 1987)
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Abstract:
The central theme of the work presented in this thesis is a careful investigation of the factors influencing the attenuation of laser beam through sea water. The thesis presents a detailed report of the work done by the author on the attenuation studies in sea water and on laser propagation through a turbulent medium. The thesis contains six chapters which are more or less self-contained with separate abstracts and references. The first chapter is divided into two parts. The first part introduces the subject of laser propagation through sea water. It includes a brief
description of optical properties of sea water followed by a review of the earlier works on attenuation studies in water. The second part gives the theoretical background of the problem
of laser propagation through a turbulent medium.
Description:
Department of physics, Cochin University of Science And Technology
Rajesh, K M; Dr.Sugunan, S(Cochin University of Science and Technology, May , 2011)
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Abstract:
The present work aims to prepare visible light responsive anion doped titania via sol-gel precipitation method.The prepared catalysts were characterized by various techniques.The photocatalytic abilities of the prepared catalysts were measured by the degradation of dyes,pesticides,hydrogen production through water splitting reaction and antibacterial study.We also compared the activities of prepared catalysts with pure titania prepared in the laboratory and one of the commercial anatase titania samples.
Description:
Dept.of Applied Chemistry,Cochin University of Science and Technology