Surendran,K P; Bijumon, P V; Mohanan, P; Sebastian,M T(Department of Electronics, April 14, 2005)
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Abstract:
The MgAl2O4 ceramics were prepared by the conventional
solid-state ceramic route and the dielectric properties
studied in the microwave frequency region (3–13 GHz).
The phase purity and crystal structure were identified using
the X-ray diffraction technique. The MgAl2O4 spinel ceramics
show interesting microwave dielectric properties (εr = 8.75,
Qux f = 68 900 GHz (loss tangent = 0.00017 at 12.3 GHz),
τf =−75 ppm/◦C). The MgAl2O4 has high negative τf, which
precludes its immediate use in practical applications. Hence
the microwave dielectric properties of MgAl2O4 spinels were
tailored by adding different mole fractions of TiO2. The
εr and Q factor of the mixed phases were increased with
the molar addition of TiO2 into the spinel to form mixtures
based on (1−x)MgAl2O4-xTiO2 (x = 0.0−1.0). For x = 0.25 in (1−x)MgAl2O4-xTiO2, the microwave quality factor
reaches a maximum value of Qux f = 105 400 GHz (loss tangent
= 0.00007 at 7.5 GHz) where εr and τf are 11.035 and
−12 ppm/◦C, respectively. The microwave dielectric properties
of the newly developed 0.75MgAl2O4-0.25TiO2 dielectric is
superior to several commercially available low loss dielectric
substrates.
Roshini, Thumpakara K; Dr.Prathapan, S(Cochin University of Science & Technology, November , 2007)
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Abstract:
The synthesis and reactions of simple derivatives of 2(3H)- and 3(2H)furanones
have attracted considerable attention in recent years, primarily in
connection with development of routes to antitumor agents that contain this
ring as central structural unit. They also serve as useful synthetic building
blocks for lactones and furans and are the precursors of a wide variety of
biologically important heterocyclic systems. Although a number of syntheses
of furanones were known they were in many cases limited to specific
substitution pattems. The development of altemative strategies for the
preparation of these heterocycles is therefore of considerable importance or
continues to be a challenge.We propose to develop new and general approaches to the synthesis of
furanone ring systems from simple and readily available starting materials
since we were interested in examining their rich photochemistry. The
photochemical reactivity of Beta,gama-unsaturated lactams and lactones is a subject of current interest. Some of the prominent photoreaction pathways of
unsaturated lactones include decarbonylation, solvent addition to double
bonds, decarboxylation, migration of aryl substituents and dimerisation. lt
was reported earlier that the critical requirement for clean photochemical
cleavage of the acyl-oxygen bond is the presence ofa double bond adjacent to
the ether oxygen and 2(3H)-furanones possessing this structural requirement
undergo facile decarbonylation. But related phenanthrofuranones are isolated
as photostable end products upon irradiation. Hence we propose to synthesis a
few phenanthro-2(3H)-furanones to study the effect of a radical stabilising
group at 3-position of furanone ring on photolysis. To explore the tripletmediated
transformations of 2(3H)-furanones in polar and nonpolar solvents a
few 3,3-bis(4-chlorophenyl)-5-aryl-3H-furan-2-ones and 3,3-di(p-tolyl)-5-aryl-
3H-furan-2-ones were synthesised from the corresponding
dibenzoylstyrene precursors by neat thermolysis. Our aim was to study the
nature of intermediates involved in these transformations.We also explored the possibility of developing a new and general
approach to the synthesis of 3(2H)-furanones from simple and readily
available starting materials since such general procedures are not available.
The protocol developed by us employs readily available phenanthrenequinone
and various 4-substituted acetophenones as starting materials and provides
easy access to the required 3(2H)-furanone targets. These furanone
derivatives have immense potential for further investigations .We also aimed the synthesis of a few dibenzoylalkene-type systems
such as acenaphthenone-2—ylidene ketones and phenanthrenone-9-ylidene
ketones. These systems were expected to undergo thermal rearrangement to
give furanones and spirofuranones. Also these systems can be categorised as
quinonemethides which are valuable synthetic intermediates.
Description:
Department of Applied Chemistry, Cochin University of Science
and Technology
Pyroja, S; Paulose,C S(Department of Biotechnology, Faculty of Science, April , 2002)
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Abstract:
The work is an attempt to understand the role of 5-HT, 5-HT1A and 5-HT2C receptors in the regulation of liver cell proliferation using in vivo and in vitro models. The work also focuses on the brain serotonergic changes associated with hapatocyte proliferation and apoptosis to delineate its regulatory function. The investigation of mechanisms involving different models of hepatocyte proliferation contributes to our knowledge about serotonergic regulation of cell growth, apoptosis and carcinogenesis of liver. The study reveals that the alteration of the 5-HT1A and 5-HT2C receptor function and gene expression in the brain stem, cerebral cortex and hypothalamus play an important role in the sympathetic regulation of cell proliferation, neoplastic transformation and apoptosis. The functional balance between 5-HT1A and 5-HT2C receptor plays an important role in regulating hepatocyte proliferation, neoplastic transformation and hepatic apoptosis. The regulatory role of 5-HT1A and 5-HT2C receptor during neoplastic transformation and apoptosis could lead to possible therapeutic intervention in the treatment of cancers and have immense clinical importance.
Baby,Jacob; Dr.Sankaranarayanan, K C(Cochin University of Science and Technology, March 1, 1985)
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Abstract:
An attempt is made to identify the causes for the decline of Kerala’s agricultural export performance. The study evaluates the policies of the government and programmes of the organization assigned with the task of development of export trade of specific commodities. The researcher recommends a plan of action with long term perspective and suggests appropriate strategies for the export development of the traditional and nontraditional agricultural items. T he thesis also review trends in the world trade of the major exports from Kerala
Description:
Department of Applied Economics, Cochin University of Science and Technology
One of the most amazing and wonderful mathematicians of all time is Srinivasa
Ramanujan. He provides a shining example for each of us in at least two
important ways. First, his magical genius has provided mathematicians for
the last one hundred years with wonderful research directions that have greatly
enriched our understanding of many areas of Mathematics. Second, he has
shown us that someone born in poverty can achieve success beyond our wildest
dreams. The world is a better place because he lived”.
Anil,R Nair; Dr.Sadasivan Nair,G(Cochin University Of Science And Technology, October 20, 2009)
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Abstract:
Access to education becomes an issue of equity with diverse
claims from stakeholders justifying their rights based on perceptions
of equity — both social and individual. In-spite of the phenomenal
increase since independence in the number of institutions imparting
education and the number of beneficiaries, India being the second
largest nation in terms of population of the young finds its resources
spread thin in meeting the demand for education. Quality education
comes at a premium in India whether it is provided in the private or
in the public sector. Education seemingly enables the individuals,
singly and collectively. to overcome the social barriers perpetuated
by the caste system. Taken together, these unleash grave demands on formulating equitable standards. It is in this context that
identifying the deserving for favourable consideration becomes all
the more important.
In this sea of claims and counter-claims, this thesis tries to
identify the issues involved on the question of equitable access to
education on the basis of the factual position in the field of
education. Identifying the issues correctly provides the necessary
impetus for framing the questions that provide meaningful answers.
The objective of this research is to help formulate the policy
guidelines governing the principles of equity that is needed to
ensure universal access to education in India.
Description:
School of Legal Studies, Cochin University of Science and
Technology
Dimethylacetals of ketones; cyclohexanone, acetophenone,
and benzophenone have been prepared by reacting
ketones with methanol under mild reaction conditions.
Large pore zeolites (H-Y and its rare earth metal, Ce3+, La3+,
and RE3+ modified forms), and mesoporous clay (K-10
montmorillonite and its cerium exchanged counterpart) with
regular pore structure, silica and silica-alumina have been
used as catalysts. Clay catalysts are found to be much more
active than zeolites, thanks to slightly bigger pore size. The
nature of the pores of the solid acid catalysts determine acetalization
efficiency of a particular catalyst. As evidenced
by the reaction time studies, the catalyst decay is greater
over the zeolites than over the clays. Carrying out the reaction
with ketones of different molecular sizes it is shown
that K-10 clays and rare earth exchanged H-Y zeolites are
promising environmentally friendly catalysts for their use in
the production fine chemicals.
Three enzymes, α-amylase, glucoamylase and invertase, were immobilized on acid activated montmorillonite K 10 via two independent techniques, adsorption and covalent binding. The immobilized enzymes were characterized by XRD, N2 adsorption measurements and 27Al MAS-NMR spectroscopy. The XRD patterns showed that all enzymes were intercalated into the clay inter-layer space. The entire protein backbone was situated at the periphery of the clay matrix. Intercalation occurred through the side chains of the amino acid residues. A decrease in surface area and pore volume upon immobilization supported this observation. The extent of intercalation was greater for the covalently bound systems. NMR data showed that tetrahedral Al species were involved during enzyme adsorption whereas octahedral Al was involved during covalent binding. The immobilized enzymes demonstrated enhanced storage stability. While the free enzymes lost all activity within a period of 10 days, the immobilized forms retained appreciable activity even after 30 days of storage. Reusability also improved upon immobilization. Here again, covalently bound enzymes exhibited better characteristics than their adsorbed counterparts. The immobilized enzymes could be successfully used continuously in the packed bed reactor for about 96 hours without much loss in activity. Immobilized glucoamylase demonstrated the best results.
Sugunan, S; Anto, Paul(Indian Journal of Chemistry, December , 1997)
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Abstract:
The surface acidity and basicity of mixed oxides of Zr and Y
and their mixed oxides have been determined by titration method
using Hammett indicators. The acid base properties are evaluated
on a common scale of acid strength. Liquid phase reduction of
cyclohexanone has been selected as a model reaction to correlate
catalytic activity.
Sugunan, S; Rani, G D; Unnikrishnan, P A(J. Mater. Sci. Technol., 1994)
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Abstract:
The electron donor properties of Pr6O11 activated at 300. 500 and 800°C are reported from the studies
on adsorption of electron acceptors of various electron affinity (7. 7, 8, 8-tetracyanoquinodimethane.
2, 3. 5, 6-tetrachloro-l, 4-benzoquin one. p-dinitrobenzene. and
m-dinitrobenzene) in three solvents (acetonitrile, 1,4-dioxan and ethyl acetate). The extent of electron
transfer during adsorption is understood from magnetic measurements and ESR spectral data. The corresponding
data on mixed oxides of Pr and Al are reported for various compositions, The acid / base
properties of these oxides are determined using a set of Hammett indicators.
Sugunan, S; Chemparathy, G V; Anto, Paul(Indian Journal of Engineering & Materials Sciences, 1996)
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Abstract:
The surface acidity and basicity of binary oxides of Zr with Ce and La are determined using a series of Hammet indicators and Ho,,max values are reported. The generation of new acid sites habe been ascribed to the charge imbalance of M1-O-M2 bonds, where M1 and M2 are metal atoms. Both Bronsted and Lewis acid sites contribute to the acidity of the oxides
Sugunan, S; Devika Rani, G(Journal of Materials Science Letters, 1993)
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Abstract:
The electron donor properties of Nd2O3 activated at 300, 500 and 800°C were investigated
through studies on the adsorption of electron acceptors of various electron affinities - 7, 7, 8,8-tetracyanoquinodimethane (2.84 eV). 2, 3, 5, 6-tetrachloro-l , 4-benzoquinone (2.40 eV).
p-dinitrobenzene (1.77 eV), and m-dinitrobenzene (1.26 eV) in solvents acetonitrile and
1, 4-dioxan. The extent of electron transfer during adsorption has been found from magnetic
measurements and electronic spectral data. The corresponding data on mixed oxides of
neodymium and aluminium are reported for various. compositions. The acid-base properties of
catalysts were also determined using a set of Hammett indicators.
Binsy,Varghese V; Dr.Sugunan, S(Cochin University Of Science And Technology, February , 1998)
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Abstract:
Catalysis research underpins the science of modern chemical processing
and fuel technologies. Catalysis is commercially one of the most important
technologies in national economies. Solid state heterogeneous catalyst materials such
as metal oxides and metal particles on ceramic oxide substrates are most common.
They are typically used with commodity gases and liquid reactants. Selective oxidation
catalysts of hydrocarbon feedstocks is the dominant process of converting them to key
industrial chemicals, polymers and energy sources.[1]
In the absence of a unique successfiil theory of heterogeneous catalysis,
attempts are being made to correlate catalytic activity with some specific properties of
the solid surface. Such correlations help to narrow down the search for a good catalyst
for a given reaction.
The heterogeneous catalytic performance of material depends on many
factors such as [2]
Crystal and surface structure of the catalyst.
Thermodynamic stability of the catalyst and the reactant.
Acid- base properties of the solid surface.
Surface defect properties of the catalyst.Electronic
and semiconducting properties and the band structure.
Co-existence of dilferent types of ions or structures.
Adsorption sites and adsorbed species such as oxygen.Preparation method of catalyst , surface area and nature of heat treatment.
Molecular structure of the reactants.
Many systematic investigations have been performed to correlate
catalytic performances with the above mentioned properties. Many of these
investigations remain isolated and further research is needed to bridge the gap in the
present knowledge of the field.
Description:
Department of Applied Chemistry, Cochin University of Science & Technology