Rosily, A V; Dr. Chandramohanakumar, N(Cochin University of Science & Technology, December , 2002)
[+]
[-]
Abstract:
Sulphur is a non conservative major element and is the most active species in the redox processes in nature, especially in aquatic environment . The varying oxidative states from-2 to +6 make it possible to enter into many of the biogeochemical processes. Thus the history, present and future of the chemical composition and behaviour of the natural aquatic systems and sediments have footprints of the sulphur chemistry.Mangroves are considered to be the most productive, fishery supportive ecosystem operating in the intertidal regions. The interlinking of the mangroves with the sulphur chemistry is attempted here.
Description:
Department of Chemical Oceanography, Cochin University of Science and Technology
Princy, K G; Dr. Rani, Joseph; Dr.Sudha Kartha, C(Cochin University of Science & Technology, June , 2002)
[+]
[-]
Abstract:
The primary aim of this work has been to develop conductive silicone and
nitrile rubbers, which are extensively used for making conductive pads in telephone
sets, calculators and other applications. Another objective of the work has been to
synthesise and characterize novel conducting polymers based on glyoxal and
paraphenylenediamine- poly(p-phenylenediazomethine. Conducting polymer
matrices were developed from polymer blends such as poly(pphenylenediazomethine),
polyethylene, PVC and silica and their properties were
studied.
Description:
Department of Polymer Science and Rubber Technology,Cochin University of Science
and Technology
Prafulla, V; Dr.Lakshmanan, P T(Central Institute of Fisheries Technology, 2002)
[+]
[-]
Abstract:
The present study entitled "Investigations on the Distribution Characteristics of Heavy Metals in Squid (Loligo spp.) in Relation to Levels in Food Fishes from the West Coast of India with a Perspective on Seafood Safety"attempts to
establish the base line data on metal levels in squids along the west
coast of India. The study is of great relevance in the present context
when utmost importance is being given for producing wholesome
seafoods especially in the export market with a perspective on seafood
safety.The thesis presents a comprehensive account of the base line
data on important heavy metals, viz., Hg, Cd, Pb, Cu, Zn, Fe, Mn Cr
and Ni in the edible and non-edible body components of the most
abundant Loligo species, viz., L. duvauceli caught along the west
coast of India.
Unnikrishnan, K P; Jayan, Thomas; V P N Nampoori; Vallabhan, C P G(Elsevier, June , 2002)
[+]
[-]
Abstract:
Here we report measurements of third-order susceptibility χ(3), figure of merit F defined as χ(3)/α (where α is the absorption coefficient) and second hyperpolarizability 〈γ〉 of some metal substituted phthalocyanines and a naphthalocyanine in solutions of dimethyl formamide using degenerate four wave mixing at 532 nm under nanosecond excitation. It was found that among samples investigated, bis-naphthalocyanine possessed the highest value of 〈γ〉 followed by the bis-phthalocyanine. This observation is explained on the basis that bis-naphthalocyanine followed by bis-phthalocyanine has higher degree of π electron conjugation.
Ramankutty, C.G; Sugunan, S; Bejoy, Thomas(Elsevier, September 9, 2002)
[+]
[-]
Abstract:
Preparation of simple and mixed ferrospinels of nickel, cobalt and copper and their sulphated analogues by the room temperature coprecipitation method yielded fine particles with high surface areas. Study of the vapour phase decomposition of cyclohexanol at 300 °C over all the ferrospinel systems showed very good conversions yielding cyclohexene by dehydration and/or cyclohexanone by dehydrogenation, as the major products. Sulphation very much enhanced the dehydration activity over all the samples. A good correlation was obtained between the dehydration activities of the simple ferrites and their weak plus medium strength acidities (usually of the Brφnsted type) determined independently by the n-butylamine adsorption and ammonia-TPD methods. Mixed ferrites containing copper showed a general decrease in acidities and a drastic decrease in dehydration activities. There was no general correlation between the basicity parameters obtained by electron donor studies and the ratio of dehydrogenation to dehydration activities. There was a leap in the dehydrogenation activities in the case of all the ferrospinel samples containing copper. Along with the basic properties, the redox properties of copper ion have been invoked to account for this added activity.
The present work undertakes the preparation and physico-chemical characterisation of iron promoted sulphated zirconia
(SZ) with different amounts of iron loading and their application to Friedel-Crafts benzoylation of benzene, toluene and xylene
under different experimental conditions, XRD and laser Raman techniques reveal the stabilisation of the tetragonal phase of
zirconia and the existence of iron in highly dispersed form as Fe203 on the catalyst surface. The surface acidic properties were
determined by ammonia temperature programmed desorption (TPD) and perylene adsorption, The results were supported by
the TGA studies after adsorption of pyridine and 2,6-dimethylpyridine (2,6-DMP), Strong Lewis acid sites on the surface, which
are evident from TPD and perylene adsorption studies. explain the high catalytic activity of the systems towards benzoylation.
The experimental results provide evidence for the truly heterogeneous nature of the reaction. The studies also establish the
resistance to deactivation in the metal incorporated sulphated systems.
Achamma, Kurian; Unnikrishnan, K P; Thomas Lee, S; V P N Nampoori; Vallabhan, C P G(Taylor & Francis, 2002)
[+]
[-]
Abstract:
A sensitive method based on the principle of photothermal phenomena to realize optical
logic gates is presented. A dual beam thermal lens method using low power cw lasers in a
dye-doped polymer can be very effectively used as an alternate technique to perform the
logical function such as NAND, AND and OR.
Binoy, G S; Dr. Vasudevan, K(Cochin University of Science & Technology, June , 2002)
[+]
[-]
Abstract:
The thesis is the outcome of the experimental and theoretical investigations carried out on a novel slotted microstrip antenna.The antenna excites two resonance frequencies and provides orthogonal polarization. The radiation characteristics of the antenna are studied in detail. The antenna design is optimized using IE3D electromagnetic simulation tool. The frequency-Difference Time-Domain (FDTD) method is employed for the analysis of the antenna.The antenna can be used for personal and satellite communication applications.
Description:
Department of Electronics, Cochin University of Science and Technology.
Sugunan, S; Renuka, N K(Indian Journal of Chemistry, April , 2002)
[+]
[-]
Abstract:
Physico-chemical characterization of DY203/V2O5 systems prepared through wet impregnation method has been carried
out using various techniques like EDX, XRD, FTIR. thermal studies, BET surface area, pore volume and pore size
distribution analysis. The amount of vanadia incorporated has been found to influence the surface properties of dysprosia.
The spectroscopic results combining with X-ray analysis reveal that vanadia species exist predominantly as isolated
amorphous vanadyl units along with crystalline dysprosium orthovanadate. Basicity studies have been conducted by
adsorption of electron acceptors and acidity and acid strength distribution by temperature programmed desorption of
ammonia. Cyclohexanol decomposition has been employed as a chemical probe reaction to examine the effect of vanadia on
the acid base property of Dy2O3. Incorporation of vanadia titrates thc Lewis acid and base sites of Dy2O3, while an
enhancement of Bronsted acid sites has been noticed. Data have been correlated with the catalytic activity of these oxides
towards the vapour phase methylation of phenol