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.
Somatic embryos were induced from scutellar callus of immature zygotic embryos of T aestivum cv.
Chinese Spring. Observations on precociously germinating somatic embryos revealed that: (i) In the initial
stages the coleoptile is split, exposes the shoot apex and forms a green trichomatous leafy structure.
In the germinating zygotic embryo, the coleoptile is tubular, (ii) Unlike what has been inferred earlier the
leafy structure is the coleoptile and not the scutellum, (iii) Bipolarity of the embryoid is established later
when root develops at the basal end.
When simulation modeling is used for
performance improvement studies of complex systems such as
transport terminals, domain specific conceptual modeling
constructs could be used by modelers to create structured
models. A two stage procedure which includes identification of
the problem characteristics/cluster - ‘knowledge acquisition’
and identification of standard models for the problem cluster –
‘model abstraction’ was found to be effective in creating
structured models when applied to certain logistic terminal
systems. In this paper we discuss some methods and examples
related the knowledge acquisition and model abstraction stages
for the development of three different types of model categories
of terminal systems
Description:
Proceedings of the World Congress on Engineering and Computer Science 2012 Vol II
WCECS 2012, October 24-26, 2012, San Francisco, USA
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
Revi Kala, S; Dr. Ramamurthy, V D(Cochin University Of Science And Technology, March 14, 1985)
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Abstract:
The present study was undertaken to observe the phytoplankton (distones,dinoflageliates,and blue green algae) blooms occurring along the south west coast of India at various seasons from February 1982 to august 1984.The centers selected for collection and observation were off Quilon, off Alleppey ,off Calicut. A total number of 25 phytoplankton blooms were studied. Characterisation of phytoplankton blooms include observing the cell counts from the day of its appearance to its day of disappearance. The appearance ,duration and locality of the blooms were also noted
Description:
School Of Marine Sciences
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
Indulal,G; Vijayakumar,Ambat(Department of Mathematics, 2002)
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Abstract:
Two graphs G and H are Turker equivalent if they have the same set of Turker angles.
In this paper some Turker equivalent family of graphs are obtained.
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