Krishna Kumar,P A; Chandramohanakumar, N(Cochin University of Science and Technology, October , 1999)
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Abstract:
This study focuses on the fractionation and quantification of chlorophenols, the most important and potential pollutant in this category, the distribution and seasonal dynamics of MBAS, phenols and clorophenols and development of a model to describe the chemical reactivity of the estuary are utilizing the dynamics of boron. The CES is highly influenced by various anthropogenic activities like discharge of agricultural, industrial and urban wastes operation of shipyard, oil and other transporting activities, fishing, dredging etc. Seasonal values of MBAS showed high values in the surface water during monsoon compared to premonsoon and postmonsoon. In the Cochin estuary o-chlorophenol and p-chlorophenol showed low values in the surface water compared to bottom water in the northern part of the estuary and higher values in the surface water in the southern part
Akula Raghunadha, Rao; Basil, Mathew(Naval Physical & Oceanographic Laboratory,Defence Research and Development Organisation, 2008)
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Abstract:
In the present study the availability of satellite altimeter sea level data with good spatial and temporal resolution is explored to describe and understand circulation of the tropical Indian Ocean. The derived geostrophic circulations showed large variability in all scales. The seasonal cycle described using monthly climatology generated using 12 years SSH data from 1993 to 2004 revealed several new aspects of tropical Indian Ocean circulation. The interannual variability presented in this study using monthly means of SSH data for 12 years have shown large year-to-year variability. The EOF analysis has shown the influence of several periodic signals in the annual and interannual scales where the relative strengths of the signals also varied from year to year. Since one of the reasons for this kind of variability in circulation is the presence of planetary waves. This study discussed the influence of such waves on circulation by presenting two cases one in the Arabian Sea and other in the Bay of Bengal.
Sugunan, S; Sherly, K B; Devika Rani, G(React. Kinet.Catal.Lett., 1993)
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Abstract:
The limit of electron transfer in electron affinity from
the oxide surface to the electron acceptor (EA) are reported
from the adsorption of EA on DY203, mixed oxides
of DY203 with alumina and mixed oxides of Y203 with y-alumina.
The extent of electron transfer is understood
from magnetic measurements.
Sugunan, S; Binsy, Varghese(Indian Journal of Chemistry, September , 1998)
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Abstract:
The electron donating properties, surface acidity/ basicity and catalytic activity of cerium - zirconium mixed
oxides at various compositions have been reported at an activation temperature of 500 degree C. The catalytic activity
for the esterification of acetic acid with n-butanol has heen correlated with electron donating properties and
surface acidity/basicity of the oxides.
Jalaja, Malayan J; Dr.Sugunan, S(Cochin University of Science and Technology, December , 1994)
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Abstract:
The rare earths have provided fascinating field
for chemists confronted with problems of their separation
and purification. The rare earths become available in
relatively pure form in recent years due to the development
of efficient separation methods, largely as a byproduct of
the atomic energy programmes of various countries. The
rare earths often called lanthanides from La (Z=57) to Lu
(Z=7l) display subtle variation of properties through the
series, while the differences become appreciable for the
elements that are farther apart.
Description:
Department of
Applied Chemistry, Cochin University of Science and
Technology
The electron donating properties, surface acidity/basicity and catalytic activity of lanthana for various dopant concentrations of strontium are reported at two activation temperatures. The catalytic activity has been correlated with electron donating properties and surface acidity/basicity of the oxide.
Anantharaman, M R; Senoy, Thomas; Al-Harthi, S H; Ramanujan, R V; Zhao, Bangchuan; Liu, Yan; Wang, Lan(AIP Publishing, February 10, 2009)
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Abstract:
The growth of Fe–Ni based amorphous nanocolumns has been studied using atomic force
microscopy. The root mean square roughness of the film surface increased with the deposition time
but showed a little change at higher deposition time. It was found that the separation between the
nanostructures increased sharply during the initial stages of growth and the change was less
pronounced at higher deposition time. During the initial stages of the column growth, a roughening
process due to self shadowing is dominant and, as the deposition time increases, a smoothening
mechanism takes place due to the surface diffusion of adatoms
Ramankutty, C G; Dr.Sugunan, S(Cochin University of Science & Technology, November , 2000)
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Abstract:
The present study describes the surface properties and catalytic activities of
ferrospinels containing Co, Ni and Cu prepared by the low temperature route. Various
physico-chemical methods have been adopted to characterise the systems. The reactions
carried out are the Friedel-Crafts benzoylation of aromatics and the cyclohexanol
decomposition. We have attempted the sulphate modification of the ferrites and have
studied the surface and catalytic properties of the sulphated analogues.The work is presented in six chapters, the last chapter giving the summary and
conclusions of the results presented earlier. Our samples prove as potential catalysts for
the benzoylation of aromatics , for which truly heterogeneous catalysts are rare. Again ,
the materials show remarkable dehydration/dehydrogenation activities during
cyclohexanol decomposition. There is plenty of scope for research in this field, especially
in the development of environmentally benign catalysts for acylation reactions.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Ferrospinels of nickel, cobalt and copper and their sulphated analogues were prepared by the room temperature coprecipitation
route to yield samples with high surface areas. The intrinsic acidity among the ferrites was found to decrease in
the order: cobalt> nickel> copper. Sulphation caused an increase in the number of weak and medium strong acid sites,
whereas the strong acid sites were left unaffected. Electron donor studies revealed that copper ferrite has both the highest
proportion of strong sites and the lowest proportion of weak basic sites. All the ferrite samples proved to be good catalysts
for the benzoy lation of toluene with benzoyl chloride. copper and cobalt ferrites being much more active than nickel ferrite.
The catalytic activity for benzoylation was not much influenced by sulphation, but it increased remarkably with calcination
temperature of the catalyst. Surface Lewis acid sites, provided by the octahedral cations on the spinel surface, are suggested
to be responsible for the catalytic activity for the benzoylation reaction.
Nishamol,Kanat; Sugunan, S(Department of applied chemistry, 2002)
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Abstract:
In recent years considerable advances have been achieved in the study of the surface structure and mechanism of action of environmentally benign heterogeneous catalysts. The study entitled as surface properties and catalytic activity of manganese ferrospinels. In the present study we have prepared manganese ferrospinels of general formula Mn(1-x)BxFe2O4 via low temperature controlled co-precipation method. The study employed low temperature co-precipitation method for the preparation ofMn(1-x)BxFe2O4 specimens, where B is a metal cation such as Cr,Co, Ni,Cu and Zn. The catalytic activities of the systems were investigated for liquid-phase benzoylation of aromatic compounds and phenol hydroxylation and for vapour-phase reactions such as aniline alkylation, phenol methylation and ODH of ethylbenzene. The different series of manganese ferrites are proved to be excellent catalysts for various industrially important reactions such as Friedel-crafts benzoylation of aromatic compounds, methylation of aniline and phenol, hydroxylation of phenol and oxidative dehydrogenation of ethylbenzene. Due to the tightening of the environmental regulations, production of diphenols from phenol hydroxylation and reduction of phenolic pollutants in waste waters using these catalysts can be a promising approach because it demands only simple techniques and produce little environmental pollution.
Smitha, V K; Suja, H; Joyce, Jacob; Sugunan, S(Indian Journal of Chemistry, February , 2003)
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Abstract:
Preparation and physico-chemical characterization or
phosphate modified zirconia systems and their application to
Friedel-Crafts benzylation and benzoylation of toluene have been
reported. The influence of transition metals on the surface
properties and catalytic activity has also been discussed.
Renuka, N K; Dr.Sugunan, S(Cochin University of Science & Technology, November , 2000)
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Abstract:
An investigation on the physical and chemical characterisation of rare earth oxide
supported vanadia is attempted in the present study. La2O3, Sm2O3 and DY2O3 serve the
purpose of supports. Supported catalysts were prepared and characterised using various
physico chemical techniques. A detailed investigation of acid base properties is also
carried out. The nature of interaction of vanadia with lanthanide oxide is discussed and
the effect of vanadia loading on the activity of the systems towards reactions of industrial
importance is explored.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Sugunan, S; Renuka, N K(Indian Journal of Chemistry, February , 2002)
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Abstract:
Sm2O3 - vanadia catalysts have been prepared by wet
impregnation method using NH4VO3 solution. The surface
properties of the prepared catalysts have been studied using FTIR.
XRD. surface area and pore volume data. The acid-base properties
of the system have been investigated by titrimetric method using
Hammett indicators. adsorption of electron acceptors as well as
decomposition of cyclohexanol. Phenol alkylation reaction by
methanol has been carried out to investigate the catalytic activity.
It has been observed that the selectivity of the products depends
upon the composition of the supported system
Vijayakumar, K P; Dr.Purushothaman, C(Cochin University of Science and Technology, May 28, 1984)
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Abstract:
The thesis aims to present the results of experimental investigations on the changes of optical properties of metallic thin films due to heating. The parameters which are measured are reflectivity, refractive indices and the ellipsometric quantities V and A . The materials used in the studies are metals like Silver, Aluminium and Copper. By applying the optical method the interdiffusion taking place in multilayer
‘films of Aluminium and Silver has also been studied. Special interest has been taken to reveal the mechanisms of the hillock growth and surface roughness caused by heating and their relation with the stress in the film
Description:
Department of Physics, Cochin University of Science and Technology