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.
Biju, John; Rajendran, C P(Cochin University of Science and Technology, 2003)
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Abstract:
The purpose of the present study is to understand the surface deformation associated with the Killari and Wadakkancheri earthquake and to examine if there are any evidence of occurrence of paleo-earthquakes in this region or its vicinity. The present study is an attempt to characterize active tectonic structures from two areas within penisular India: the sites of 1993 Killari (Latur) (Mb 6.3) and 1994 Wadakkancheri (M 4.3) earthquakes in the Precambrian shield. The main objectives of the study are to isolate structures related to active tectonism, constraint the style of near – surface deformation and identify previous events by interpreting the deformational features. The study indicates the existence of a NW-SE trending pre-existing fault, passing through the epicentral area of the 1993 Killari earthquake. It presents the salient features obtained during the field investigations in and around the rupture zone. Details of mapping of the scrap, trenching, and shallow drilling are discussed here. It presents the geologic and tectonic settings of the Wadakkancheri area and the local seismicity; interpretation of remote sensing data and a detailed geomorphic analysis. Quantitative geomorphic analysis around the epicenter of the Wadakkancheri earthquake indicates suitable neotectonic rejuvenation. Evaluation of remote sensing data shows distinct linear features including the presence of potentially active WNW-ESE trending fault within the Precambrian shear zone. The study concludes that the earthquakes in the shield area are mostly associated with discrete faults that are developed in association with the preexisting shear zones or structurally weak zones
Madhu, V; Dr.Mohan Kumar, K(Cochin University of Science and Technology, October , 2004)
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Abstract:
The present work is an attempt to understand the characteristics of the upper troposphere and lower stratosphere over the Asian summer monsoon region, more specifically over the Indian subcontinent. Mainly three important parameters are taken such as zonal wind, temperature and ozone over the UT/LS of the Asian summer monsoon region. It made a detailed study of its interannual variability and characteristics of theses parameters during the Indian summer monsoon period. Monthly values of zonal wind and temperature from the NCEP/NCAR reanalysis for the period 1960-2002 are used for the present study. Also the daily overpass total ozone data for the 12 Indian stations (from low latitude to high latitudes) from the TOMS Nimbus 7 satellite for the period 1979 to 1992 were also used to understand the total ozone variation over the Indian region.
The study reveals that if QBO phases in the stratosphere is easterly or weak westerly then the respective monsoon is found to be DRY or below Normal . On the other hand, if the phase is westerly or weak easterly the respective Indian summer monsoon is noted as a WET year. This connection of stratospheric QBO phases and Indian summer monsoon gives more insight in to the long-term predictions of Indian summer monsoon rainfall. Wavelet analysis and EOF methods are the two advanced statistical techniques used in the present study to explore more information of the zonal wind that from the smaller scale to higher scale variability over the Asian summer monsoon region. The interannual variability of temperature for different stratospheric and tropospheric levels over the Asian summer monsoon region have been studied. An attempt has been made to understand the total ozone characteristics and its interannual variablilty over 12 Indian stations spread from south latitudes to north latitudes. Finally it found that the upper troposphere and lower stratosphere contribute significantly to monsoon variability and climate changes. It is also observed that there exists a link between the stratospheric QBO and Indian summer monsoon
Helvin, Vincent; Saritha G, Bhatt(Cochin University of Science and Technology, May 7, 2014)
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Abstract:
Soil community genomics or metagenomics is employed in this study to analyze the evolutionary related
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ness of mangrove microbial community. The metagenomic DNA was isolated from mangrove sediment and
16SrDNA was amplified using universal primers. The amplicons were ligated into pTZ57R/T cloning vector and transformed
onto E. coli JM109 host cells. The recombinant plasmids were isolated from positive clones and the insert was confirmed
by its reamplification. The amplicons were subjected to Amplified Ribosomal DNA Restriction Analysis (ARDRA) using three
different tetra cutter restriction enzymes namely Sau3A1, Hha1 and HpaII. The 16SrDNA insert were sequenced and their
identity was determined. The sequences were submitted to NCBI database and accession numbers obtained. The phylo
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genetic tree was constructed based on Neighbor-Joining technique. Clones belonged to two major phyla of the bacterial
domain, namely Firmicutes and Proteobacteria, with members of Firmicutes predominating. The microbial diversity of the
mangrove sediment was explored in this manner.