Nandini Menon, N; Dr. Ravindranatha Menon, N(Cochin University of Science & Technology, April , 1997)
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Abstract:
The thesis deals with different aspects connected with the distribution and toxicity of PHC in crude oils in the aquatic environment and marine molluscs. Information has been gathered and presented on the present status of research in the field based on a thorough review of recent literature. It is seen from the literature that the resident time of PHC becomes lesser and lesser when crude oil is discharged in large quantities into the coastal waters where excess oxygenation light penetration, temperature availability and strong tidal currents persist. This results in the reduction of the onslaught of oil pollution. This probably shows that taxic insult of crude oil in tropical shores will be relatively lesser than that occurring in temperate and boreal waters. However, there is no record of major episodal oil pollution comparable in quantum and extent to that of Torrey Canyon or Amoco Cadiz which prevents a more reliable analysis on the issue. Considerable controversy exists on the method of estimation of PHC in seawater. However, Ultra-violet fluorescence spectroscopy has been widely recommended as an analytical tool for the determination of total hydrocarbons. Similarly representation of values as chrysene equivalents has been recognised as the most reliable method of Quantum representation.
Description:
Division of Marine Biology, Microbiology and Biochemistry, school of Marine Sciences, Cochin University of Science and Technology
Mohandas, N N; Dr. George, M K(Indian Council of Agricultural Research, Central Marine Fisheries Institute, January , 1997)
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Abstract:
The objective of present investigation was to study the population genetic structure of S. longiceps by applying three different basic population genetic techniques such as cytogenetics, non-enzymatic biochemicalgenetics (general protein) and morphomeristics/metrics.
Rani, Joseph(John Wiley & Sons,Inc., December 29, 1997)
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Abstract:
ABSTRACT: The electrical conductivity of silicone rubber vulcanizates containing carbon
blacks [e.g., acetylene black, lamp black, and ISAF (N-234) black] were investigated.
The change in electrical conductivity with varying amounts of carbon blacks and the
temperature dependence was measured. The mechanical properties like tensile
strength, tear strength, elongation at break, hardness, etc., of the vulcanizates were
determined. A comparative study of the electrical conductivity of the composites revealed
that the electrical conductivity of the composites made with acetylene black was
higher than that of the composites made of other blacks.
Laser irradiation at wavelength 514 nm was used to study the effect, of lasers in inducing
chromosomal aberrations at mitosis. This study offers a new radiation system which could be used for the
induction of mutations. Results are compared with those obtained from studies using y-rays as irradiation
source.
A comparative study of the effect of laser in inducing chromosomal
aberrations at 488 nm was done in Vicia faba L. (faba bean)
and Allium cepa L. (onion) with Argon ion laser (Spectra Physics Model
171). Seeds and bulbs of V. faba and A. cepa were subjected to laser irradiation
by 488 nm excitations from Argon ion laser source at power levels
200 and 400 mW with power densities 2.25 mW cm-2 and 4.49 mW
cm-2 and different exposure times ( 10, 20, 30 & 40 ..... tc) similar to the effect of other physical and chemical mutagens, laser caused a dose
dependent decrease in mitotic index and a rise in mitotic aberrations
when compared to the control . In both plant species, mutations were
observed in all stages of mitotic cell cycle . The total percentage of aberrations
was two fold higher at 400 mW than at 200 mW exposure.
Edwin, Xavier; Dr.Girijavallabhan, C P(Cochin University of Science & Technology, March , 1997)
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Abstract:
The present thesis is centered around the study of electrical and thermal
properties of certain selected photonic materials.We have studied the electrical conduction mechanism in various
phases of certain selected photonic materials and those associated with different phase
transitions occurring in them. A phase transition leaves its own impressions on the key
parameters like electrical conductivity and dielectric constant. However, the activation
energy calculation reveals the dominant factor responsible for conduction process.PA measurements of thermal diffusivity in certain other important photonic
materials are included in the remaining part of the research work presented in this
thesis. PA technique is a promising tool for studying thermal diffusivities of solid
samples in any form. Because of its crucial role and common occurrence in heat flow
problems, the thermal diffusivity determination is often necessary and knowledge of
thermal diffusivity can intum be used to calculate the thermal conductivity. Especially,knowledge of the thermal diffusivity of semiconductors is important due to its relation
to the power dissipation problem in microelectronic and optoelectronic devices which
limits their performances. More than that, the thermal properties, especially those of
thin films are of growing interest in microelectronics and microsystems because of the
heat removal problem involved in highly integrated devices. The prescribed chapter
of the present theis demonstrates how direct measurement of thermal diffusivity can be
carried out in thin films of interest in a simple and elegant manner using PA techniques.
Although results of only representative measurements viz; thermal diffusivity values in
Indium, Aluminium, Silver and CdS thin films are given here, evaluation of this
quantity for any photonic and / electronic material can be carried out using this
technique in a very simple and straight forward manner.
Description:
International School of Photonics,Cochin University of Science and Technology