Jayasankar, M; Dr.Warrier, K G K(National Institute for Interdisciplinary Science and Technology, December , 2009)
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Abstract:
The thesis entitled "Sol-Gel Alumina Nano Composites for
Functional Applications" investigate sol-gel methods of synthesis of alumina
nanocomposites special reference to alumina-aluminium titanate and alumina-lanthanum
phosphate composites. The functional properties such as thermal
expansion coefficient and thermal shock resistance, machinability of composites as well as thermal protection are highlighted in addition to novel
approach in synthesis of composites.A general introduction of alumina matrix composites materials,
followed by brief coverage of alumina-aluminium titanate and alumina-lanthanum
phosphate composites is highlight of the first chapter. The second
chapter deals with the sol-gel synthesis of aluminium titanate and alumina-aluminium
titanate composite. The synthesis of machinable substrate, based on
alumina and lanthanum phosphate forms the basis of the third chapter. The
fourth chapter describes the sol-gel coating of mullite on SiC substrate for the
possible gas filtration application.
Sankar, Sasidharan; Dr K.G.K Warrier(Cochin University of Science and Technology, January 16, 2015)
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Abstract:
Lanthanum phosphate is one among the lanthanide family of “Rare Earths” following the periodic table of elements. Known under the generic name, Monazite, the rare earth phosphates have melting points above 1900 °C, high thermal phase stability, low thermal conductivity and thermal expansion coefficient similar to some of the high temperature oxides like alumina and zirconia.
Smitha, Sasidharan; Dr.Warrier, K G K(Cochin University of Science & Technology, July , 2009)
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Abstract:
The thesis covers a systematic investigation on the synthesis of
silica aerogels and microspheres with tailored porosity, at ambient conditions by
varying the experimental parameters as well as using organic templates.
Organically modified silica-gelatin and silica-chitosan hybrids were developed for
the first time using alkylalkoxysilanes such as MTMS and VTMS. Application of
novel silica-biopolymer antiwetting coatings on different substrates such as glass,
leather and textile is also demonstrated in the thesis.
Sibu,C P; K G K Warrier(CSIR, FACULTY OF SCIENCE, 2004)
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Abstract:
In the present work Titania bulk powders and coatings were prepared by subjecting titanium isopropoxide solution to a controlled hydrolysis-condensation process. The powders were characterized using techniques such as FTIR for their chemical interactions, TG-DTA for the thermal decomposition features, XRD for the phase assemblage, BET specific surface area analysis for the textural features. The study discusses the preparation methods and the characterization techniques employed and a detailed discussion on the physico-chemical characterization of the prepared systems. The influence of dopants and leaching on the physico-chemical properties as well as their influence on photo activity is also included. The structural/functional coatings of different Titania compositions includes in this study. Coatings on pre-treated glass surfaces with the best compositions prepared showed 90 % transmittance in the visible region.
Sajan, P; Dr. M. Junaid Bushiri(Cochin University of Science and Technology, June 5, 2016)
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Abstract:
The research on nanocrystalline materials have been of great interest for
more than 20 years due to its fundamental properties as well as development of
technology based on it. Non-toxic semiconducting nanocrystals are important
materials with wide range of applications in the areas of biotechnology, medicine,
bio-optics and for the fabrication light emitting and harvesting devices. Majority of
the II-VI semiconductors possess wide band gap along with high iconicity and are
important materials for optoelectronic devices operating under the UV excitation
sources. Among the II-VI semiconductors, ZnS is a material with good optical
transmission in the visible region with large exciton binding energy of about 40
meV. ZnS usually crystallizes in cubic form which is zinc blende or sphalerite and
its hexagonal form is in wurtzite phase. The cubic sphalerite phase of ZnS has a
band gap of 3.68 eV whereas the hexagonal (wurtzite) phase has a band gap of 3.77
eV. Moreover, ZnS is a good host lattice phosphor for photonic applications and
electroluminescent devices because of its wide band gap.
The present thesis deals with the synthesis and photoluminescence studies
of micro and nanostructured ZnS by hydrothermal and solvo-hydrothermal method.
Thesis is also focused on bioimaging application of these materials.
Syed Aftab, Husain Rizvi; Dr.Wazir, Hasan Abdi(Cochin University of Science And Technology, March , 1984)
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Abstract:
This thesis is an attempt to throw light on the works
of some Indian Mathematicians who wrote in Arabic or
persian In the Introductory Chapter on outline of
general history of Mathematics during the eighteenth
Bnd nineteenth century has been sketched. During that
period there were two streams of Mathematical activity.
On one side many eminent scholers, who wrote in Sanskrit,
.he l d the field as before without being much influenced
by other sources. On the other side there were scholars
whose writings were based on Arabic and Persian text
but who occasionally drew upon other sources also.
Description:
Department of Mathematics and Statistics, Cochin University of Science and Technology
Asha Gopalakrishnan; Dr.Unnikrishnan Nair, N(Cochin University Of Science And Technology, May 15, 1995)
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Abstract:
The term reliability of an equipment or device is
often meant to indicate the probability that it carries out
the functions expected of it adequately or without failure
and within specified performance limits at a given age for a
desired mission time when put to use under the designated
application and operating environmental stress. A broad
classification of the approaches employed in relation to
reliability studies can be made as probabilistic and
deterministic, where the main interest in the former is to
device tools and methods to identify the random mechanism
governing the failure process through a proper statistical
frame work, while the latter addresses the question of
finding the causes of failure and steps to reduce individual
failures thereby enhancing reliability. In the
probabilistic attitude to which the present study subscribes to, the concept of life distribution, a mathematical
idealisation that describes the failure times, is
fundamental and a basic question a reliability analyst has
to settle is the form of the life distribution. It is for
no other reason that a major share of the literature on the
mathematical theory of reliability is focussed on methods of
arriving at reasonable models of failure times and in
showing the failure patterns that induce such models. The
application of the methodology of life time distributions is
not confined to the assesment of endurance of equipments and
systems only, but ranges over a wide variety of scientific
investigations where the word life time may not refer to the
length of life in the literal sense, but can be concieved in
its most general form as a non-negative random variable.
Thus the tools developed in connection with modelling life
time data have found applications in other areas of research
such as actuarial science, engineering, biomedical sciences,
economics, extreme value theory etc.
Description:
Division of Statistics, School of Mathematical Sciences,
Cochin University of Science and Technology
Muraleedharan Nair,K R; Dr.Unnikrishnan Nair, N(Cochin University Of Science And Technology, May 10, 1990)
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Abstract:
It is highly desirable that any multivariate
distribution possessescharacteristic properties that
are generalisation in some sense of the corresponding
results in the univariate case. Therefore it is of
interest to examine whether a multivariate distribution
can admit such characterizations. In the exponential
context, the question to be answered is, in what meaning—
ful way can one extend the unique properties in the
univariate case in a bivariate set up? Since the lack
of memory property is the best studied and most useful
property of the exponential law, our first endeavour
in the present thesis, is to suitably extend this
property and its equivalent forms so as to characterize
the Gumbel's bivariate exponential distribution.
Though there are many forms of bivariate exponential
distributions, a matching interest has not been shown
in developing corresponding discrete versions in the
form of bivariate geometric distributions. Accordingly,
attempt is also made to introduce the geometric version
of the Gumbel distribution and examine several of its
characteristic properties. A major area where exponential
models are successfully applied being reliability
theory, we also look into the role of these bivariate
laws in that context.
The present thesis is organised into five
Chapters
Description:
Department of Mathematics
and Statistics, Cochin University of Science
and Technology
This thesis entitled Reliability Modelling and Analysis in Discrete time Some Concepts and Models Useful in the Analysis of discrete life time data.The present study consists of five chapters. In Chapter II we take up the derivation of some general results useful in reliability modelling that involves two component mixtures. Expression for the failure rate, mean residual life and second moment of residual life of the mixture distributions in terms of the corresponding quantities in the component distributions are investigated. Some applications of these results are also pointed out. The role of the geometric,Waring and negative hypergeometric distributions as models of life lengths in the discrete time domain has been discussed already. While describing various reliability characteristics, it was found that they can be often considered as a class. The applicability of these models in single populations naturally extends to the case of populations composed of sub-populations making mixtures of these distributions worth investigating. Accordingly the general properties, various reliability characteristics and characterizations of these models are discussed in chapter III. Inference of parameters in mixture distribution is usually a difficult problem because the mass function of the mixture is a linear function of the component masses that makes manipulation of the likelihood equations, leastsquare function etc and the resulting computations.very difficult. We show that one of our characterizations help in inferring the parameters of the geometric mixture without involving computational hazards. As mentioned in the review of results in the previous sections, partial moments were not studied extensively in literature especially in the case of discrete distributions. Chapters IV and V deal with descending and ascending partial factorial moments. Apart from studying their properties, we prove characterizations of distributions by functional forms of partial moments and establish recurrence relations between successive moments for some well known families. It is further demonstrated that partial moments are equally efficient and convenient compared to many of the conventional tools to resolve practical problems in reliability modelling and analysis. The study concludes by indicating some new problems that surfaced during the course of the present investigation which could be the subject for a future work in this area.
Description:
Department of Statistics, Cochin
University of Science and Technology
Thomas, Joseph; Dr.Jathavedan, M(Cochin University of Science and Technology, June , 1993)
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Abstract:
This thesis contains a study of conservation laws of
fluid mechanics. These conservation laws though classical, have
been put to extensive studies in t:he past many decades
Description:
Department of Mathematics And Statistics, Cochin University of Science And Technology
Sreekumar, R; Thrivikraman,T; Chakravarti, R S(Department of Mathematics, Faculty of Science, 2002)
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Abstract:
The main purpose of the study is to extent concept of the class of spaces called ‘generalized metric spaces’ to fuzzy context and investigates its properties. Any class of spaces defined by a property possessed by all metric spaces could technically be called as a class of ‘generalized metric spaces’. But the term is meant for classes, which are ‘close’ to metrizable spaces in some under certain kinds of mappings. The theory of generalized metric spaces is closely related to ‘metrization theory’. The class of spaces likes Morita’s M- spaces, Borges’s w-spaces, Arhangelskii’s p-spaces, Okuyama’s spaces have major roles in the theory of generalized metric spaces. The thesis introduces fuzzy metrizable spaces, fuzzy submetrizable spaces and proves some characterizations of fuzzy submetrizable spaces, and also the fuzzy generalized metric spaces like fuzzy w-spaces, fuzzy Moore spaces, fuzzy M-spaces, fuzzy k-spaces, fuzzy -spaces study of their properties, prove some equivalent conditions for fuzzy p-spaces. The concept of a network is one of the most useful tools in the theory of generalized metric spaces. The -spaces is a class of generalized metric spaces having a network.
Babu, Sundar S; Dr.Thrivikraman, T(Cochin University Of Science And Technology, March 21, 1989)
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Abstract:
It is believed that every fuzzy generalization should be
formulated in such a way that it contain the ordinary set
theoretic notion as a special case. Therefore the definition of fuzzy topology in the line of C.L.CHANG E9]
with an arbitrary complete and distributive lattice as the
membership set is taken. Almost all the results proved and presented in this thesis can, in a sense, be called generalizations of corresponding results in ordinary set theory and set topology. However the tools and the methods have to be in many of the cases, new. Here an attempt is made to solve the problem of complementation in the lattice of fuzzy
topologies on a set. It is proved that in general, the
lattice of fuzzy topologies is not complemented. Complements
of some fuzzy topologies are found out. It is observed that
(L,X) is not uniquely complemented. However, a complete
analysis of the problem of complementation in the lattice
of fuzzy topologies is yet to be found out
Description:
Depantment of Mathematics and Statistics
Cochin University of Scince
and Technology
Baby,B V; Dr.Babu, Joseph K(Cochin University of Science and Technology, April 3, 1985)
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Abstract:
An immense variety of problems in theoretical physics are of the non-linear type. Non~linear partial differential equations (NPDE) have almost become the rule rather than an exception in diverse branches of physics such as fluid mechanics, field theory, particle physics, statistical physics and optics, and the construction of exact solutions of these equations constitutes
one of the most vigorous activities in theoretical physics today. The thesis entitled ‘Some Non-linear Problems in Theoretical Physics’ addresses various aspects of this problem at the classical level. For obtaining exact solutions we have used mathematical tools like the bilinear
operator method, base equation technique and similarity method with emphasis on its group theoretical aspects. The thesis deals with certain methods of finding exact solutions of a number of non-linear partial differential equations of importance to theoretical physics. Some of these new solutions are of relevance from the applications point of view in diverse branches such as elementary particle physics, field theory, solid state physics and non-linear optics and give some insight into the stable or unstable behavior of dynamical Systems The thesis consists of six chapters.
Description:
Department of Physics, Cochin University of Science and Technology