Thomas,P T; George,K K(Department of Applied Economics, September , 1994)
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Abstract:
It is hoped that the present study by analysing the
dynamics of agrarian change and peasant mobility may contribute
to the on-going debate on this issue in India and other developing
countries. It may also help to throw light on the validity of some
of the theories formulated on the basis of experience in different
regions and at different times. The study is likely to be of
special importance as it covers an area which has one of the
highest densities of population. The area has also witnessed
sweeping changes in agrarian structure as a result of the most
radical land reforms among the Indian states.
Dayana, M.K.; Dr. Varkey, A.M(Cochin University of Science and Technology, October 26, 2015)
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Abstract:
This is a study of land use law in India. Land use Controls has been a subject
of controversy since the human settlement. Gamut of control increased with human
development. Now the controls are for many purposes.Nuisance created through various land use was tried to be avoidedthrough the common law controls7. Whether the utility of the activity outweighs
the environmental consideration was the consideration before the court. A
standard definition8 of nuisance could meet most of the problems relating to land
use. Later on, planning and zoning laws brought in major changes. Health, safety
and facilities of others attracted land use controls9. After the Stockholm the sphere
of government interference increased. Several legislations were enacted. Existing
legislations were modified. These come in conflict with the interests of different
sections of society. Coastal Regulations10 and high range protection11 are
manifestations of such unrest. A systematic study on these issues is of current
interest. Exploring of some areas in this respect is also relevant in this respect.
Anantharaman, M R; Lija, Joy K; Sooraj, V; Swapna, Nair S; Narayanan, T N; Ajayan, P M; Sethulakshmi, N(AIP Publishing, March 28, 2014)
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Abstract:
Commercial samples of Magnetite with size ranging from 25–30nm were coated with polyaniline by
using radio frequency plasma polymerization to achieve a core shell structure of magnetic nanoparticle
(core)–Polyaniline (shell). High resolution transmission electron microscopy images confirm the core
shell architecture of polyaniline coated iron oxide. The dielectric properties of the material were
studied before and after plasma treatment. The polymer coated magnetite particles exhibited a large
dielectric permittivity with respect to uncoated samples. The dielectric behavior was modeled using a
Maxwell–Wagner capacitor model. A plausible mechanism for the enhancement of dielectric
permittivity is proposed
Sarasu, T N; Dr.George, M J(Cochin University of Science and Technology, March , 1987)
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Abstract:
Lobsters are renowned the world over as tasty delicacies and are in great demand for Epicurian gourests. As a result these animals found in different parts of the world from countries like India they are mostly frozen and exported thus earning considerable foreign exchange for the country. Importance of this crustacean is thus well known and whatever harvested from nature are utilized to the maximum extent. The demand being much more than what is being produced the need for artificial culture becomes evident. In this context a complete knowledge of the lifecycle ,larval biology and their culture is very essential. Thus with the object of studying the life history of the commercially important lobsters fished from Indian waters the larval biology of panulirus homarus has been taken up as the project for the present study
Radhakrishnan, P; Nampoori, V P N; Girijavallabhan, C P; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
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Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
Nampoori, V P N; Radhakrishnan, P; Girijavallabhan, C P; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
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Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
Girijavallabhan, C P; Radhakrishnan, P; Nampoori, V P N; Geetha, K; Rajesh, M(Journal of Optics A: Pure and Applied Optics, Institute of Physics Publishing, January 13, 2006)
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[-]
Abstract:
We present a compact solid-state laser based on leaky mode propagation
from a dye-doped polymer free-standing film waveguide. The edge emitted
spectrum clearly indicated the existence of periodic resonant modes. The
reflections from the lateral faces of the free-standing film provided the
optical feedback thus giving rise to a Fabry–Perot like optical cavity. This
together with the guidance through the gain medium gave rise to intense
narrow emission lines. For a pump energy of 1.82 mJ/pulse, an intense line
with FWHM ∼0.4 nmwas observed at 576.5 nm.
Rejeena, I; Dr. P. Radhakrishnan(Cochin University of Science and Technology, April 23, 2015)
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Abstract:
Nonlinear optics is a broad field of research and technology that
encompasses subject matter in the field of Physics, Chemistry, and Engineering.
It is the branch of Optics that describes the behavior of light in nonlinear media,
that is, media in which the dielectric polarization P responds nonlinearly to the
electric field E of the light. This nonlinearity is typically only observed at very
high light intensities. This area has applications in all optical and electro optical
devices used for communication, optical storage and optical computing. Many
nonlinear optical effects have proved to be versatile probes for understanding
basic and applied problems. Nonlinear optical devices use nonlinear dependence
of refractive index or absorption coefficient on the applied field. These nonlinear
optical devices are passive devices and are referred to as intelligent or smart
materials owing to the fact that the sensing, processing and activating functions
required for optical processes are inherent to them which are otherwise separate
in dynamic devices.The large interest in nonlinear optical crystalline materials has been
motivated by their potential use in the fabrication of all-optical photonic devices.
Transparent crystalline materials can exhibit different kinds of
optical nonlinearities which are associated with a nonlinear polarization. The
choice of the most suitable crystal material for a given application is often far
from trivial; it should involve the consideration of many aspects. A high
nonlinearity for frequency conversion of ultra-short pulses does not help if the
interaction length is strongly limited by a large group velocity mismatch and the
low damage threshold limits the applicable optical intensities. Also, it can be
highly desirable to use a crystal material which can be critically phasematched
at room temperature. Among the different types of nonlinear crystals, metal halides and
tartrates have attracted due to their importance in photonics. Metal halides like
lead halides have drawn attention because they exhibit interesting features from
the stand point of the electron-lattice interaction .These materials are important
for their luminescent properties. Tartrate single crystals show many interesting
physical properties such as ferroelectric, piezoelectric, dielectric and optical
characteristics. They are used for nonlinear optical devices based on their optical
transmission characteristics. Among the several tartrate compounds, Strontium
tartrate, Calcium tartrate and Cadmium tartrate have received greater attention
on account of their ferroelectric, nonlinear optical and spectral characteristics.
The present thesis reports the linear and nonlinear aspects of these crystals and
their potential applications in the field of photonics.
Santhi Ani, Joseph; Gaurav, Sharma; Misha, Hari; Mathew, S; Radhakrishnan, P; Nampoori, V P N(Optical Society of America, 2010)
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Abstract:
We demonstrate the possibility of realizing, all-optical switching in gold nanosol. Two overlapping laser beams are used for this purpose, due to which a low-power beam passing collinear to a high-power beam will undergo cross phase modulation and thereby distort the spatial profile. This is taken to advantage for performing logic operations. We have also measured the threshold pump power to obtain a NOT gate and the minimum response time of the device. Contrary to the general notion that the response time of thermal effects used in this application is of the order of milliseconds, we prove that short pump pulses can result in fast switching. Different combinations of beam splitters and combiners will lead to the formation of other logic functions too.
Optical fiber based laser induced fluorescence (LIF)
measurements were carried out using Rhodamine B to analyze
two different species of bacteria , a Gram-positive bacteria
namely Bacillus smithii , and fibrin alginolvticus, a Gram-
negative bacteria . The fiber sensor was clearly able to distinguish
between the two species of bacteria . Quenching effect of the dye
Rhodamine B by Bacillus smithii was observed . The effect of dye
on the samples was also studied in detail.
Nampoori, V P N(Wiley Inter Science, March 27, 2007)
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Abstract:
Optical fiber based laser induced fluorescence (LIF)
measurements were carried out using Rhodamine B to analyze
two different species of bacteria , a Gram-positive bacteria
namely Bacillus .cmithii , and fibrin alginolvticus, a Gram-'
negative bacteria . The fiber sensor was clearly able to distinguish
between the two species of bacteria . Quenching effect of the dye
Rhodamine B by Bacillus smitltii was observed . The effect of dye
on the samples was also studied in detail.
Reethamma, Thomas; Nampoori, V P N(Elsevier, 1990)
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Abstract:
Fluorescence of BaS: Sm phosphor has been studied using a pulsed Nitrogen laser (337.1 nm) as the excitation source. The spectrum consists of a broad band in the region 540–660nm superposed by the characteristic Sm3+ lines. Energy level splitting pattern of Sm3+ due to crystal field effects has been calculated and relevent field parameters are evaluated. Analysis shows that Sm3+ takes up Ba2+ substitutional sites.
Nibu, A George; Vallabhan, C P G; Nampoori, V P N; George, A K; Radhakrishnan, P(Taylor & Francis, 2001)
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Abstract:
In this paper we report the use of a laser induced phoroacoustic technique for the detection of multiple phase transitions in heptyl-oxy-cyanobiphenyl (70CB) and octyl-oxy-cyanobiphenyl (80CB) liquid crystals. The observed photoacoustic signal amplitude profile carries clear signatures of two tirst order transitions in 70CB and two tirst order and a second order transitions in 80CB. Analysis of the experimental data using Rosencwaig-Gersho theory shows that the sudden decrease in the photoacoustic (PA) signal amplitude during phase transitions is due to a sharp increase in the heat capacity of the samples near the transition temperatures.
Sajan, D George(Cochin University of Science & Technology, November , 2003)
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Abstract:
Discovery of coherent optical sources four decades ago has revolutionized all fields of scientific development. One of the path breaking applications of lasers is the emergence of various thermo optic techniques to unravel some of the mysteries of light matter interactions.Thermo optic technique is a valuable tool to evaluate optical and thermal properties of materials in solid,liquid and gaseous states .This technique can also be employed effectively in nondestructive quality evaluation. In this doctoral thesis , the use of photothermal techniques based on photoacoustic and photothermal deflection phenomena for the study of certain class of photonics materials such as semiconductors, nano metal dispersed ceramics, composites of conducting polymers and liquid crystals is elaborated.
Description:
International School of Photonics,
Cochin University of Science and Technology
Jacob, Philip; Manivannan, S; Dhanuskodi, S; Tiwari, S K(Springer, 2008)
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Abstract:
N-alkyl-2,6-dimethyl-4(1H)-pyridinones, salts of
4-dimethylaminopyridine and 2-amino-5-nitropyridine are considered
to be potential candidates for nonlinear optical (NLO)
applications, in particular for the generation of blue-green laser
radiation. Single crystals were grown following the slow evaporation
technique at constant temperature. Single-shot laserinduced
surface damage thresholds in the range 3–10 GW/cm2
were measured using a 18 ns Q-switched Nd:YAG laser. The
surface morphologies of the damaged crystals were examined
under an optical microscope and the nature of damage identified.
The Vicker’s microhardness was determined at a load of
98.07 mN. The thermal transport properties, thermal diffusivity
(α), thermal effusivity (e), thermal conductivity (K) and heat
capacity (Cp), of the grown crystals were measured by an improved
photopyroelectric technique at room temperature. All
the results are presented and discussed.
Radhakrishnan, P; Nampoori, V P N; Girijavallabhan, C P; Sajan, D George; Aji, A Anapara; K G K Warrier(Proceedings of SPIE, 2003)
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Abstract:
In this paper, we report the measurements of thermal diffusivity of nano Ag metal dispersed ceramic alumina
matrix sintered at different temperatures using laser induced non-destructive photoacoustic technique. Measurements of
thermal diffusivity also have been carried out on specimens with various concentration of nano metal. Analysis of the
data is done on the basis of one-dimensional model of Rosencwaig and Gersho. The present measurements on the
thermal diffusivity of nano metal dispersed ceramic alumina shows that porosity has a great influence on the heat
transport and the thermal diffusivity value. The present analysis also shows that the inclusion of nano metal into
ceramic matrix increases its interconnectivity and hence the thermal diffusivity value. The present study on the samples
sintered at different temperature shows that the porosity of the ceramics varies considerably with the change in sintering
temperature. The results are interpreted in terms of phonon assisted heat transfer mechanism and the exclusion of pores
with the increase in sintering temperature
Nampoori, V P N; Radhakrishnan, P; Girijavallabhan, C P; Sajan, D George; Aji, A Anapara; K G K Warrier(Proceedings of SPIE, 2003)
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Abstract:
In this paper, we report the measurements of thermal diffusivity of nano Ag metal dispersed ceramic alumina
matrix sintered at different temperatures using laser induced non-destructive photoacoustic technique. Measurements of
thermal diffusivity also have been carried out on specimens with various concentration of nano metal. Analysis of the
data is done on the basis of one-dimensional model of Rosencwaig and Gersho. The present measurements on the
thermal diffusivity of nano metal dispersed ceramic alumina shows that porosity has a great influence on the heat
transport and the thermal diffusivity value. The present analysis also shows that the inclusion of nano metal into
ceramic matrix increases its interconnectivity and hence the thermal diffusivity value. The present study on the samples
sintered at different temperature shows that the porosity of the ceramics varies considerably with the change in sintering
temperature. The results are interpreted in terms of phonon assisted heat transfer mechanism and the exclusion of pores
with the increase in sintering temperature