Fincy Jose, P; Dr.Sugunan, S(Cochin University Of Science And Technology, December 12, 2004)
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Abstract:
The objective of the present work is to improve the textural and structural
properties of cerium oxide by the incorporation of transition metals as well as sulphate
ions. We have incorporated tungsten, molybdenum and chromium oxide into
pure as well as sulphated cerium oxide and the catalytic systems thus prepared were
characterised using various techniques. lndustrially important reactions such as
acetalization and deacetalization, oxidative dehydrogenation of ethylbenzene, MTBE
synthesis and Beckmann rearrangement of cinnamaldoxime and salicylaldoxime have
been selected for the measurement of the catalytic activity of the systems.
The work is presented in eight chapters
Description:
Department
of Applied Chemistry, Cochin University of Science and Technology
Sunajadevi, K R; Dr.Sugunan, S(Cochin University Of Science And Technology, September 22, 2004)
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Abstract:
in the present study, we have prepared and evaluated the physical and
chemical properties and catalytic activities of transition metal loaded sulfated
titania via the sol-gel route. Sol-gel method is widely used for preparing porous
materials having controlled properties and leads to the formation of oxide
particles in nano range, which are spherical or interconnected to each other.
Characterization using various physico-chemical techniques and a
detailed study of acidic properties are also carried out. Some reactions of
industrial importance such as Friedel-Crafts reaction, fen-butylation of phenol,Beckmann rearrangement of cyclohexanone oxime, nitration of phenol and
photochemical degradation of methylene blue have been selected for catalytic
activity study in the present venture.
The work is organized into eight chapters
Description:
Department of Applied Chemistry
Cochin University of Science and Technology
Manju, Kurian; Dr.Prathapan, S; Dr.Sugunan, S(Cochin University Of Science And Technology, February 15, 2004)
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Abstract:
The present work is oriented to obtain a comparative evaluation of the
physicochemical properties and catalytic activities of iron, aluminium and iron aluminium
mixed pillared montmorillonites and their transition metal exchanged analogues.
Reactions of industrial importance like Friedel Crafts alkylations, catalytic wet peroxide
oxidation of phenol and MTBE synthesis have been selected for the present study. The
thesis is structured into seven chapters. First chapter deals with a brief introduction and
literature survey on pillared clays. Second chapter explains the materials and methods
employed in the work. Results and discussions on the characterisation techniques are
described in the third chapter. The subsequent three chapters describe the catalytic
activities of pillared clays in the industrially important reactions. Last chapter comprises
the summary of the investigations and the conclusions drawn from the earlier chapters
Description:
Department of Applied Chemistry
Cochin University of Science and Technology
Rajesh Krishnan, G; Dr. Sreekumar, K(Cochin University of Science and Technology, June , 2008)
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Abstract:
The present thesis has described the development of some heterogeneous
catalysts based on polymer supported dendrimers. Attachment of dendrimers to
crosslinked polymer produced new catalysts with combined benefits of both
dendrimers and heterogeneous catalysts. These were used as heterogeneous
catalysts in selected reactions. All possible attempts were taken to avoid
halogenated and aromatic solvents and toxic reagents. In short the present work
has dealt with development of environmental friendly catalysts based on
dendrimers.
Description:
Department of Applied Chemistry, Cochin University of Science and
Technology
Rahna,K Shamsudeen; Dr.Sugunan, S(Cochin University of Science & Technology, December , 2001)
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Abstract:
In the present study, we have prepared and evaluated the physical and
chemical properties and catalytic activities of various single, mixed and modified
pillared montmorillonites. The single oxide pillared clays include AI-, Fe- and Cr-pillared
montmorillonites. The mixed oxide pillared montmorillonites such as Fe-AI
and Cr-AI pillared systems with various Fe(Cr)/Al ratios are also prepared.
Modification of iron-pillared system is done by vanadia impregnation.
Characterisation using various physico-chemical techniques and a detailed study of
acidic properties are also carried out. Major part of our work is oriented to evaluate
the catalytic activity of the pillared systems towards certain important catalytic
reactions. Our samples are found to be excellent catalysts for the reactions namely
Friedel-Crafts benzylation and benzoylation, methylation of aniline and catalytic wet
peroxide oxidation of phenol.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Deepa, C S; Dr.Sugunan, S(Cochin University of Science & Technology, August , 2002)
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Abstract:
In the present work, we have tried to evaluate systematically the surface properties
of sulphated tin oxide systems modified with three different transition metal oxides viz. iron
oxide, tungsten oxide and molybdenum oxide. The catalytic activities of these systems are
checked and compared by carrying out some industrially important reactions such as
oxidative dehydrogenation of ethylbenzene and Friedel-Crafts reactions.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Maya, G; Dr.Sugunan, S(Cochin University of Science and Technology, December , 2006)
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Abstract:
The aim of catalysis research is to apply the catalyst successfully in economically
important reactions in an environmentally friendly way. The present work focuses on the
modification of structural and surface properties of ceria and ceria-zirconia catalysts by
the incorporation of transition metals. The applications of these catalysts in industrially
important reactions like ethylbenzene oxidation, alkylation of aromatics are also
investigated.Sol-gel method is effective for the preparation of transition metal modified
ceria and ceria-zirconia mixed oxide since it produces catalyst with highly dispersed
incorporated metal. Unlike that of impregnation method plugging of pores is not
prominent for sol-gel derived catalyst materials. This prevents loss of surface area on
metal modification as evident for BET surface area measurements.The powder X-ray diffraction analysis confirms the cubic structure of
transition metal modified ceria and ceria-zirconia catalysts. The thermal stability is
evident from TGA/DTA analysis. DR UV-vis spectra provide information on the
coordination environment of the incorporated metal. EPR analysis ofCr, Mn and Cu
modified ceria and a ceria-zirconia catalyst reveals the presence of different oxidation
states of incorporated metal.Temperature programmed desorption of ammonia and thermogravimetric
desorption of 2,6-dimethyl pyridine confirms the enhancement of acidity on metal incorporation. High a-methyl styrene selectivity in cumene cracking reaction implies
the presence of comparatively more number of Lewis acid sites with some amount of
Bronsted acid sites. The formation of cyclohexanone during cyclohexanol
decomposition confirms the presence of basic sites on the catalyst surface.Mn and Cr modified catalysts show better activity towards ethylbenzene
oxidation. A redox mechanism through oxometal pathway is suggested.All the catalysts were found to be active towards benzylation of toluene and
a-xylene. The selectivity towards monoalkylated products remains almost 100%. The
catalytic activity is correlated with the Lewis acidity of the prepared systems.The activity of the catalysts towards methylation of phenols depends on the
strength acid sites as well as the redox properties of the catalysts. A strong
dependence of methylation activity on the total acidity is illustrated.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Nisha, P C; Dr. George, K C(Central Marine Fisheries Research Institute, October , 2006)
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Abstract:
The present investigation revealed three types of circulating haemocytes
in the haemolymph of F. indicus: hyalinocytes, small-granule haemocytes, and
large-granule haemocytes. Intermediate stages indicate the maturing process of a
single cell. The presence of enzymes such as peroxidase, phenoloxidase and acid
phosphatase in the haemocytes, and the substantial production of oxygen radicals
during phagocytosis show that the haemocytes are capable of mounting a fme
cellular defense mechanism. The enzyme activities of the serum and the presence
of agglutinins in the serum, which may act as opsonins, agglutinate foreign
particles and augment phagocytosis, confirm the presence of a superior humoral
immune system in F. indicus.Bacterial infection caused considerable variations in the cellular and
humoral factors, such as the number of circulating cells and haemagglutinating
activity, especially in the initial hours of infection. The total haemocyte count,
haemagglutination titer and phenoloxidase enzyme showed significant reductions
on bacterial presence and could be used as indicators of bacterial infection.The number of circulating cells showed drastic fluctuation on exposure to
pollutants. Nuvan at low concentrations was able to produce changes in the
haemolymph factors and in the tissue organization, which implies that the animal
is under stress and is easily prone to infections. Exposure to nuvan resulted in
significant variation in all of the cellular and humoral factors, especially, the total
haemocyte count, percentage of small granule haemocytes, phagocytic activity
and the haemagglutinating activity, which might be good indicators of pesticide
pollution. Heavy metal exposure caused significant increase in total haemocyte
count and reduction in phenoloxidase enzyme activity Even changes in the
physio-chemical parameters, such as salinity caused fluctuations in the defense
factors, indicating stress in this euryhaline species. The dietary incorporation of a
commercial immunostimulant containing P-l,3 glucan resulted in stimulation of
some of the humoral defense factors of F indicus, but was time dependent. The
modulations, on exposure to various external factors, in the cellular and humoral
factors, especially, total haemocyte count, phagocytic activity, haemagglutinating
activity and the phenoloxidase and acid phosphatase enzymes suggest that these
parameters could be used as indicators of the health status of F indicus, which
assist in better monitoring and effective health management of this important
cultured species.
George,K K; Dr.Parameswaran, Nair N(Cochin University of Science and Technology, October 19, 1982)
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Abstract:
The problem of regional disparities in economic
development is for India an inheritance from the colonial past.
At the beginning of the First Five Year Plan (1950-51), three
years after the advent of independence, the per capita State
income showed considerable inter—state variations.
Description:
School of Management Studies, Cochin University of Science and Technology
Zeena, Ravi P; Dr.Chandramohanakumar, N(Cochin University of Science & Technology, May , 2005)
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Abstract:
Mangrove swamps are unique inter-tidal wetland ecosystems found in sheltered tropical and subtropical shores.Mangrove sediments can be considered as large reservoirs of amino acids,which exist in several different forms,like free amino acids in the sediment micropores,as amino acids,peptides or proteins bound to clay minerals or as amino acids,peptides or proteins bound to humic colloids.Inorder to assess survival conditions of organisms of mangroves,it is important to understand stability of amino acids in the sediments.The amounts of amino acids present in sediment represent a balance between its synthesis and destruction by microorganisms.Thus amino acid analysis offers more insight into the processes of diagenesis,which changes the nature and characteristics of organic matter deposition and decomposition.
Description:
Department of Chemical
Oceanography Cochin University of Science
and Technology
Manoj,R; Jayaraj, M K(Department of Physics, October , 2006)
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Abstract:
Materials exhibiting transparency and electrical conductivity simultaneously,
transparent conductors, Transparent conducting oxides (TCOs), which have
high transparency through the visible spectrum and high electrical
conductivity are already being used in numerous applications. Low-emission
windows that allow visible light through while reflecting the infrared, this
keeps the heat out in summer, or the heat in, in winter. A thin conducting
layer on or in between the glass panes achieves this. Low-emission windows
use mostly F-doped SnO2. Most of these TCO’s are n type semiconductors
and are utilized in a variety of commercial applications, such as flat-panel
displays, photovoltaic devices, and electrochromic windows, in which they
serve as transparent electrodes. Novel functions may be integrated into the
materials since oxides have a variety of elements and crystal structures,
providing great potential for realizing a diverse range of active functions.
However, the application of TCOs has been restricted to transparent
electrodes, notwithstanding the fact that TCOs are n-type semiconductors.
The primary reason is the lack of p-type TCOs, because many of the active
functions in semiconductors originate from the nature of the pn-junction. In
1997, H. Kawazoe et al.[2] reported CuAlO2 thin films as a first p-type TCO
along with a chemical design concept for the exploration of other p-type
TCOs.
Sivaprasad, P.; Prof. (Dr). C. A. Babu(Cochin University of Science and Technology, May 3, 2015)
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Abstract:
The aerosols in the atmosphere play major role in the radiation balance of the Earthatmosphere
system. Direct and indirect impact of aerosols on the weather and climate still
remains as a topic to be investigated in detail. The effect of aerosols on the radiation budget and
thereby circulation pattern is important and requires further study. A detailed analysis of the
aerosol properties, their variability and meteorological processes that affect the aerosol
properties and distribution over the Indian region is performed in the thesis. The doctoral thesis
entitled “Characteristics of aerosols over the Indian region and their variability associated
with atmospheric conditions” contains 7 chapters. This thesis presents results on the analysis
on the distribution (spatial and temporal) and characteristics of the aerosols over the Indian
region and adjoining seas. Regional and stationwise data were analysed and methods such as
modeling and statistical analysis are implemented to understand the aerosol properties,
classification and transportation.
Chapter-1 presents a brief introduction on the aerosols, their measurement techniques,
impact of aerosols on the atmospheric radiation budget, climatic and geographic features of the
study area and the literature review on the previous studies. It provides a basic understanding in
the field of study and objective of the thesis. Definition of the aerosols, their sources/sinks and
classification of the particles according to optical and microphysical properties are described.
Different measurement techniques such as sampling and remote sensing methods are explained
in detail. Physical parameters used to describe aerosol properties and effect of aerosols on the
radiation distribution are also discussed. The chapter also explains the objectives of the thesis
and description of climatic features of the study area.