Ravindran, T; Dr.Joseph,Francis D(Cochin University of Science And Technology, March , 1989)
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Abstract:
In the present study, the photochemical
depolymerisation of NR in toluene, in presence of
H202 and a homogenizing solvent (Methanol/Tetrahydro—
furan) so as to get hydroxyl terminated liquid natural
rubber (HTNR) has been carried out. The copolymeri—
sation of this product with butane 1,4 diol and toluene
2,4 diisocyanate in presence of a catalyst, dibutyl tin
dilaurate, to produce polyurethanes with HTNR soft segments
is also reported. The preparation of block
copolymers based on poly(ethylene oxide) with varying
molecular weights and HTNR are also discussed along with
a detailed study on their thermal and mechanical properties
Description:
Department of Polymer science and Rubber technology, Cochin University of Science And Technology
George, V C; Dr.Samuel, C T(Cochin University Of Science And Technology, September 14, 1991)
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Abstract:
In the present study. extensive investigations were
carried out on various factors affecting the selectivity of
prawn gill nets with reference to material, mesh size,
coefficient of hanging secolouration. Effect of tidal current
on fishing height of prawn gill net and seasonal variation of
catch during the course of these investigations were also
studied.
Description:
Department of Industrial Fisheries. Cochin
University of science and Technology
Aloysius, R P; Dr.Syamaprasad,U(Cochin University Of Science And Technology, December 30, 2002)
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Abstract:
The application vistas of superconductors have widened very
much since the discovery of high TC superconductors (HTS) as many of the
applications can be realised at 77 K rather than going down to 4.2 K, the
liquid He temperature. One such application is the HTS current lead which is
used to connect a superconducting system with a room temperature power
source. Minimising heat leak to the cryogenic environment is the main
advantage of introducing current leads into superconducting systems. The
properties of HTSS likes zero resistance (avoiding joule heating) and very
low thermal conductivity (minimized conductive heat transfer) make them
ideal candidates to be used as current leads. There are two forms of HTS
current leads. (i) bulk form (tube or rod) prepared either from YBCO or
BSCCO and (ii) tape form prepared from Bi-2223 multifilamentary tapes.
The tape form of current leads has many advantages with respect to the
mechanical and thermal stability related criteria. Crucial information on
various aspects of HTS current lead development are not available in the
literature as those are kept proprietary by various companies around the
world. The present work has been undertaken to tailor the properties of
multifilamentary tapes for the current lead application and to optimise the
processing parameters of the same for enhanced critical current density and
field tolerance. Also it is the aim of the present investigation is to prepare
prototype current leads engineered for operation in conduction cooled mode
and test them for operational stability
Description:
Council Of Scientific And Industrial Research [Csir]
Regional Research Laboratory
Trivandrum
Claramma, N M; Dr.Mathew, N M(Cochin University of Science and Technology, April 22, 1997)
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Abstract:
Systematic investigations on prevulcanization of NR latex with
special reference to the influence of storage of latex and after-treatments
of films, have been carried out. The other aspects studied include the
effect of temperature on sulphur prevulcanization, the extent of crosslinking,
tensile properties, stress relaxation characteristics, water absorption and
leaching characteristics of prevulcanizcd latex films
Description:
Rubber Research Institute of India
Rubber Board, Kottayam
Subramaniyan, S; Dr. Prema, P(Regional Research Laboratory, February , 2000)
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Abstract:
Xylanases with hydrolytic activity on xylan, one of the hemicellulosic
materials present in plant cell walls, have been identified long back and the
applicability of this enzyme is constantly growing. All these applications
especially the pulp and paper industries require novel enzymes. There has
been lot of documentation on microbial xylanases, however, none meeting all
the required characteristics. The characters being sought are: higher
production, higher pH and temperature optima, good stabilities under these
conditions and finally the low associated cellulase and protease production.
The present study analyses various facets of xylanase biotechnology giving
emphasis on bacterial xylanases. Fungal xylanases are having problems like
low pH values for both enzyme activity and growth. Moreover, the associated
production of cellulases at significant levels make fungal xylanases less
suitable for application in paper and pulp industries.Bacillus SSP-34 selected from 200 isolates was clearly having xylan
catabolizing nature distinct from earlier reports. The stabilities at higher
temperatures and pH values along with the optimum conditions for pH and
temperature is rendering Bacillus SSP-34 xylanase more suitable than many of
the previous reports for application in pulp and paper industries.Bacillus SSP-34 is an alkalophilic thertmotolerant bacteria which
under optimal cultural conditions as mentioned earlier, can produce 2.5 times
more xylanase than the basal medium.The 0.5% xylan concentration in the medium was found to the best
carbon source resulting in 366 IU/ml of xylanase activity. This induction was
subjected to catabolite repression by glucose. Xylose was a good inducer for
xylanase production. The combination of yeast extract and peptone selected
from several nitrogen sources resulted in the highest enzyme production
(379+-0.2 IU/ml) at the optimum final concentration of 0.5%. All the cultural
and nutritional parameters were compiled and comparative study showed that the modified medium resulted in xylanase activity of 506 IU/ml, 5 folds higher than the basal medium.The novel combination of purification techniques like ultrafiltraton,
ammonium sulphate fractionation, DEAE Sepharose anion exchange
chromatography, CM Sephadex cation exchange chromatography and Gel
permeation chromatography resulted in the purified xylanase having a specific
activity of 1723 U/mg protein with 33.3% yield. The enzyme was having a
molecular weight of 20-22 kDa. The Km of the purified xylanase was 6.5 mg
of oat spelts xylan per ml and Vmax 1233 µ mol/min/mg protein.Bacillus SSP-34 xylanase resulted in the ISO brightness increase from
41.1% to 48.5%. The hydrolytic nature of the xylanase was in the endo-form.Thus the organism Bacillus SSP-34 was having interesting
biotechnological and physiological aspects. The SSP-34 xylanase having
desired characters seems to be suited for application in paper and pulp
industries.
Jayadevan, A P; Dr. Ramesh Babu, T(Cochin University of Science and Technology, February , 2005)
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Abstract:
In this thesis quark-antiquark bound states are considered using a relativistic two-body
equation for Dirac particles. The mass spectrum of mesons includes bound states
involving two heavy quarks or one heavy and one light quark. In order to analyse these
states within a unified formalism, it is desirable to have a two-fermion equation that limits
to one body Dirac equation with a static interaction for the light quark when the other
particle's mass tends to infinity. A suitable two-body equation has been developed by Mandelzweig
and Wallace. This equation is solved in momentum space and is used to describe
the complete spectrum of mesons. The potential used in this work contains a short range
one-gluon exchange interaction and a long range linear confining and constant potential
terms. This model is used to investigate the decay processes of heavy mesons. Semileptonic
decays are more tractable since there is no final state interactions between the leptons
and hadrons that would otherwise complicate the situation. Studies on B and D meson
decays are helpful to understand the nonperturbative strong interactions of heavy mesons,
which in turn is useful to extract the details of weak interaction process. Calculation of
form factors of these semileptonic decays of pseudo scalar mesons are also presented.
Description:
Department of Physics,
Cochin University of Science and Technology
Ganapathy, R; Dr.Kuriakose, V C(Cochin University of Science And Technology, November , 2002)
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Abstract:
Studies on pulse propagation in single mode optical fibers have attracted interest
from a wide area of science and technology as they have laid down the
foundation for an in-depth understanding of the underlying physical principles,
especially in the field of optical telecommunications. The foremost among them
is discovery of the optical soliton which is considered to be one of the most significant
events of the twentieth century owing to its fantastic ability to propagate
undistorted over long distances and to remain unaflected after collision with each
other. To exploit the important propertia of optical solitons, innovative mathematical
models which take into account proper physical properties of the single
mode optical fibers demand special attention. This thesis contains a theoretical
analysis of the studies on soliton pulse propagation in single mode optical fibers.
Description:
Department of Physics, Cochin University of Science and Technology
Nijo,Varghese; Dr.Kuriakose, V C(Cochin University of Science and Technology, October , 2012)
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Abstract:
This thesis Entitled Studies on Quasinormal modes and Late-time tails black hole spacetimes. In this thesis, the signature of these new theories are probed on the evolution of field perturbations on the black hole spacetimes in the theory. Chapter 1 gives a general introduction to black holes and its perturbation formalism. Various concepts in the area covered by the thesis are also elucidated in this chapter. Chapter 2 describes the evolution of massive, charged scalar field perturbations around a Reissner-Nordstrom black hole surrounded by a static and spherically symmetric quintessence. Chapter 3 comprises the evolution of massless scalar, electromagnetic and gravitational fields around spherically symmetric black hole whose asymptotes are defined by the quintessence, with special interest on the late-time behavior. Chapter 4 examines the evolution of Dirac field around a Schwarzschild black hole surrounded by quintessence. Detailed numerical simulations are done to analyze the nature of field on different surfaces of constant radius . Chapter 5is dedicated to the study of the evolution of massless fields around the black hole geometry in the HL gravity.
Description:
Department of Physics, Cochin University of Scienceand Technology
Nijo Varghese; Prof V. C. Kuriakose(Cochin University of Science and Technology, October 14, 2012)
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Abstract:
Black hole's response to external perturbations will carry significant
information about these exotic objects. Its response, shortly
after the initial `kick', is known to be ruled by the damped oscillation
of the perturbating eld, called quasinormal modes(QNMs), followed
by the tails of decay and is the characteristic of the background black
hole spacetime.
In the last three decades, several shortcomings came out in the
Einstein's General Theory of Relativity(GTR). Such issues come, especially,
from observational cosmology and quantum eld theory. In
the rst case, for example, the observed accelerated expansion of the
universe and the hypothesized mysterious dark energy still lack a satisfactory
explanation. Secondly, GTR is a classical theory which does
not work as a fundamental theory, when one wants to achieve a full
quantum description of gravity. Due to these facts modi cation to
GTR or alternative theories for gravity have been considered. Two
potential approaches towards these problems are the quintessence
model for dark energy and Ho rava-Lifshitz(HL) gravity. Quintessence
is a dynamical model of dark energy which is often realized by scalar
eld mechanism. HL gravity is the recently proposed theory of gravity,
which is renormalizable in power counting arguments. The two
models are considered as a potential candidate in explaining these
issues.
Lorna R,Nayagam; Dr.Ram Mohan,H S(Cochin University of Science & Technology, February , 2012)
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Abstract:
The present study helped to understand the trend in rainfall patterns at smaller
spatial scales and the large regional differences in the variability of rainfall. The effect of
land use and orography on the diurnal variability is also understood. But a better
understanding on the long term variation in rainfall is possible by using a longer dataset,which may provide insight into the rainfall variation over country during the past
century.
The basic mechanism behind the interannual rainfall variability would be possible
with numerical studies using coupled Ocean-Atmosphere models. The regional
difference in the active-break conditions points to the significance of regional studies
than considering India as a single unit.
The underlying dynamics of diurnal variability need to be studied by making use
of a high resolution model as the present study could not simulate the local onshore
circulation. Also the land use modification in this study, selected a region, which is
surrounded by crop land. This implies the high possibility for the conversion of the
remaining region to agricultural land. Therefore the study is useful than considering
idealized conditions, but the adverse effect of irrigated crop is more than non-irrigated
crop. Therefore, such studies would help to understand the climate changes occurred in
the recent period. The large accumulation of rainfall between 300-600 m height of
western Ghats has been found but the reason behind this need to be studied, which is
possible by utilizing datasets that would better represent the orography and landuse over
the region in high resolution model. Similarly a detailed analysis is needed to clearly
identify the causative relations of the predictors identified with the predictant and the
physical reasons behind them. New approaches that include nonlinear relationships and
dynamical variables from model simulations can be included in the existing statistical
models to improve the skill of the models. Also the statistical models for the forecasts of
monsoon have to be continually updated.
Description:
Department of Atmospheric Sciences,Cochin University of Science
and Technology
Mohanakumaran Nair, C; Dr.Shahul,Hameed M(Cochin University of Science and Technology, August , 1993)
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Abstract:
In India scientific commercial farming of Macrobrachium is yet to get a start, the major constraint being the lack of seed. Seed collection from the natural sources alone may not be sufficient, and in such cases seed production in hatcheries is inevitable. This necessitates knowledge of the reproductive biology of the species technology development for brood stock and larval rearing, and the optimum conditions required for larval development to undertake large scale seed production.The present study was taken up with the major objectives of developing a proper, simple and feasible technology for the larval rearing of Macrobrachium, with special emphasis on. mass larval rearing suitable for commercial level operations.
Description:
Department of
Industrial Fisheries, Cochin University of Science and Technology