Jiby, K. Gopinath; Dr. K. Sreekumar(Cochin University of Science & Technology, July 30, 2015)
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Abstract:
Polymers with conjugated π-electron backbone display unusual
electronic properties such as low energy optical transition, low ionization
potentials, and high electron affinities. The properties that make these
materials attractive include a wide range of electrical conductivity,
mechanical flexibility and thermal stability. Some of the potential
applications of these conjugated polymers are in sensors, solar cells, field
effect transistors, field emission and electrochromic displays, supercapacitors
and energy storage. With recent advances in the stability of
conjugated polymer materials, and improved control of properties, a
growing number of applications are currently being explored. Some of the
important applications of conducting polymers include: they are used in
electrostatic materials, conducting adhesives, shielding against
electromagnetic interference (EMI), artificial nerves, aircraft structures,
diodes, and transistors.
Analytical expressions for the Green’s function of an annular elliptical ring microstrip
antenna (AERMA) are developed and reported. The modal, radiation and input impedance
characteristics of the TM, modes are determined from these expressions. The resonant frequencies of
odd modes are greater than that of the even modes for all TMnl modes (n = 1, 2, 3, ...) udke
elliptical microstrip structures. The radiation pattern and input imedance curves of TMI2 mode on
comparison with available experimental result shows good agreement whch provides an independent
validation to this technique. The performance of the AERMA is then investigated as a function of
thickness and substrate dielectric permittivity.
Description:
IEE Proc.-Microw. Antennas Propag., Vol. 146, No. 6, December 1999
Bejoy, Varghese; Dr. Nandakumar, V.M(Cochin University of Science and Technology, December 13, 2015)
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Abstract:
Semiconductor lasers with different types of feedback schemes have been an active research
area for many years. Feedback can induce complex phenomena in semiconductor
lasers and their investigations often helped to understand the inner mechanisms of the
laser. The possibility of using high dimensional chaos induced in semiconductor lasers
by delayed feedback, for secure communication systems was a major motivation for intense
research in the subject. Recently these systems also served as a testbed for general
investigations on delay dynamical systems. The present study focuses on the aspects of the
dynamical behavior of semiconductor lasers which are induced by delay feedback.
Santhosh,K R; Dr.Viswanadham,D V(Cochin University of Science and Technology, March , 1987)
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Abstract:
Man's inadvertent interference with the
environment by way of indiscreL¢ industrflflization
has led to the deteriorating air quality in the recent
times. The search is on to find the remedies to
confine the air pollution levels with in their thershold
limits. Theoretical studies play A crucial role in the
control and for abatment of air pollution. Improper
siting of industry is one of the most common reasons
for the increased levels of air pollution in urban
environments. A proper and effective ecological planning
is an essential first step for any region in order to
reduce the effects of air pollution. By means of
theoretical models one can obtain the pollutant distribution
in any urban area, provided the necessary data
are available with the help of which the sites for new
industries could be suggested, given the emission
inventory. Studies on air pollution meteorology serve
and aid the planners to initate remedial actions to
bring down the levels of pollution and also to out—line
the control strategy. In the present thesis some
theoretical studies on air pollution meteorology over
South India are made. The thesis is divided into
six chapters
Description:
Physical Oceanography and Meteorology Division
School of Marine Sciences, Cochin University of Science And Technology
Rosabella,K Puthur; Sebastian, K L; Sugunan, S(Cochin University of Science and Technology, October , 2001)
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Abstract:
The thesis presents the dynamics of a polymer chain under tension. It includes existing theories of polymer fracture, important theories of reaction rates, the rate using multidimensional transition state theory and apply it to the case of polyethylene etc. The main findings of the study are; the life time of the bond is somewhat sensitive to the potential lead to rather different answers, for a given potential a rough estimate of the rate can be obtained by a simples approximation that considers the dynamics of only the bond that breaks and neglects the coupling to neighboring bonds. Dynamics of neighboring bonds would decrease the rate, but usually not more than by one order of magnitude, for the breaking of polyethylene, quantum effects are important only for temperatures below 150K, the lifetime strongly depends on the strain and as the strain varies over a narrow range, the life varies rapidly from 105 seconds to 10_5 seconds, if we change one unit of the polymer by a foreign atom, say by one sulphure atom, in the main chain itself, by a weaker bond, the rate is found to increase by orders of magnitude etc.
Sunandakumari,V M; Dr.Ramanujam, N(Cochin University of Science And Technology, May , 1988)
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Abstract:
During recent years, the theory of differential inequalities has been extensively used to discuss singular perturbation problems and method of lines to partial differential equations. The present thesis deals with some differential inequality theorems and their applications to singularly perturbed initial value problems, boundary value problems for ordinary differential equations
in Banach space and initial boundary value problems for parabolic differential equations. The method of lines to parabolic and elliptic differential equations are also dealt The thesis is organised into nine chapters
Description:
Department of mathematics, Cochin University of Science And Technology
Sajan, D George; Achamma, Kurian; Martin, Lase; Nampoori, V P N; Vallabhan, C P G(SPIE, 2001)
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Abstract:
An open cell photoacoustic configuration has been employed to evaluate the thermal diffusivity of pure InP as well as InP doped with sulphur and iron. Chopped optical radiation at 488 nm from an Ar-ion laser has been used to excite photoacoustic signals which been detected by a sensitive electret microphone. Thermal diffusivity value have been calculated from phase versus chopping frequency plots. Doped sample are found to show a reduced value for thermal diffusivity in comparison with intrinsically pure sample. The results have been interpreted in terms of the mechanisms of heat generation and transmission in semiconductors.
Sugunan, S; Suja, H; Sanjay, G; Joseph, L K; Nampoori, V P N; Radhakrishnan, P(Taylor & Francis, April 1, 2009)
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Abstract:
Thermal diffusivity (TD) measurements were performed on some industrially
important dyes – auramine O (AO), malachite green and methylene blue (MB) –
adsorbed K-10 montmorillonites using photoacoustic method. The TD value for
the dye-adsorbed clay mineral was observed to change with a variation in dye
concentration. The contribution of the dye towards TD was also determined. The
repeatedly adsorbed samples with MB and AO exhibited a lower TD than the
single-adsorbed samples. TD values of sintered MB samples were also obtained
experimentally. These sintered samples exhibit a higher TD, although they show
a trend similar to that of non-sintered pellets. A variation in dye concentration
and sintering temperature can be used for tuning the TD value of the clay mineral
to the desired level
Description:
Philosophical Magazine
Vol. 89, No. 10, 1 April 2009, 895–905
Joseph, L K; Sanjay, G; Suja, H; Sugunan, S; Nampoori, V P N; Radhakrishnan, P(Taylor & Francis, April 1, 2009)
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Abstract:
Thermal diffusivity (TD) measurements were performed on some industrially
important dyes – auramine O (AO), malachite green and methylene blue (MB) –
adsorbed K-10 montmorillonites using photoacoustic method. The TD value for
the dye-adsorbed clay mineral was observed to change with a variation in dye
concentration. The contribution of the dye towards TD was also determined. The
repeatedly adsorbed samples with MB and AO exhibited a lower TD than the
single-adsorbed samples. TD values of sintered MB samples were also obtained
experimentally. These sintered samples exhibit a higher TD, although they show
a trend similar to that of non-sintered pellets. A variation in dye concentration
and sintering temperature can be used for tuning the TD value of the clay mineral
to the desired level.
Annieta, Philip K; Lyjo, Joseph K; Litty, Irimpan M; Bindu, Krishnan; Radhakrishnan, P; Nampoori, V P N; Raghu, Natarajan(WILEY-VCH Verlag, 2007)
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Abstract:
Thermal characterization of alumina–zirconia and zirconia ceramic tapes using a photoacoustic technique is presented. A transmission-mode geometry is employed for the measurement of thermal diffusivity while a reflection-mode geometry is used for the measurement of thermal effusivity. In both these geometries, the same open photoacoustic cell is used. From the measured values of thermal diffusivity and thermal effusivity, the thermal conductivity value has also been evaluated.
Anantharaman, M R; V P N Nampoori; Radhakrishnan, P; Girijavallabhan, C P; Sajan, D George; Saravanan, S; Venkatachalam, S(Physical Review, American Physical Society, June 8, 2004)
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Abstract:
Thermal diffusivity of the composites of camphor sulphonic acid (CSA) doped polyaniline (PANI) and its
composites with cobalt phthalocyanine (CoPc) has been measured using open cell photoacoustic technique.
Analysis of the data shows that the effective thermal diffusivity value can be tuned by varying the relative
volume fraction of the constituents. It is seen that polaron assisted heat transfer mechanism is dominant in CSA
doped PANI and these composites exhibit a thermal diffusivity value which is intermediate to that of CSA
doped PANI and CoPc. The results obtained are correlated with the electrical conductivity and hardness
measurements carried out on the samples
Girijavallabhan, C P; Radhakrishnan, P; Nampoori, V P N; Sajan, D George; Saravanan, S; Venkatachalam, S(Physical Review, American Physical Society, June 8, 2004)
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Abstract:
Thermal diffusivity of the composites of camphor sulphonic acid (CSA) doped polyaniline (PANI) and its
composites with cobalt phthalocyanine (CoPc) has been measured using open cell photoacoustic technique.
Analysis of the data shows that the effective thermal diffusivity value can be tuned by varying the relative
volume fraction of the constituents. It is seen that polaron assisted heat transfer mechanism is dominant in CSA
doped PANI and these composites exhibit a thermal diffusivity value which is intermediate to that of CSA
doped PANI and CoPc. The results obtained are correlated with the electrical conductivity and hardness
measurements carried out on the samples.