Gibinkumar, T R; Dr.Boopendranath, M R(Cochin University of Science & Technology, July , 2008)
[+]
[-]
Abstract:
In the context of Indian fisheries there is a paucity of information on bycatch, in general, and bycatch reduction technologies, in particular. In this study, a detailed investigation on trawl bycatch and bycatch reduction measures is attempted with a view to evolve optimized BRDs for improving selectivity of commercial shrimp trawls. The objectives of the study included design and development of hard bycatch reduction devices (BRDs), comparative evaluation of hard bycatch reduction devices, for selective trawling, bycatch characterisation of the trawl landings, off Central Kerala; and investigations on status of the existing trawling systems operated off Central Kerala.
Description:
School of Industrial Fisheries, Cochin University of Science and Technology
Aneesh Kumar, K.V.; Dr.Meenakumari,B; Dr Remesan, M. P(Cochin University of Science And Technology, November , 2013)
[+]
[-]
Abstract:
The main objectives of the present study have been
studies on the operational performance of tuna longline in
Lakshadweep Sea
studies on the efficiency of hooks in the longline operation
studies on the efficiency of baits in the longline operation
studies on bycatch in longline operation
studies on predation on the longline catch and the hook loss
encountered during the fishing operation
Description:
Fishing Technology Division
Central Institute of Fisheries Technology
CIFT Junction, P. O. Matsyapuri
(Indian Council of Agricultural Research)
Geetha K, Varier; Dr.Nampoori,V P N(Cochin University of Science and Technology, April 28, 1998)
[+]
[-]
Abstract:
Light in its physical and philosophical sense has captured the imagination of human
mind right from the dawn of civilization. The invention of lasers in the 60’s caused
a renaissance in the field of optics. This intense, monochromatic, highly directional
radiation created new frontiers in science and technology. The strong oscillating electric
field of laser radiation creates a. polarisation response that is nonlinear in character in
the medium through which it passes and the medium acts as a new source of optical
field with alternate properties. It was in this context, that the field of optoelectronics
which encompasses the generation, modulation, transmission etc. of optical radiation
has gained tremendous importance. Organic molecules and polymeric systems have
emerged as a class of promising materials of optoelectronics because they offer the
flexibility, both at the molecular and bulk levels, to optimize the nonlinearity and
other suitable properties for device applications. Organic nonlinear optical media,
which yield large third-order nonlinearities, have been widely studied to develop optical
devices like high speed switches, optical limiters etc.
Transparent polymeric materials have found one of their most promising applicationsin
lasers, in which they can be used as active elements with suitable laser dyes
doped in it. The solid-matrix dye lasers make possible combination of the advantages
of solid state lasers with the possibility of tuning the radiation over a broad spectral
range. The polymeric matrices impregnated with organic dyes have not yet widely
used because of the low resistance of the polymeric matrices to laser damage, their low
dye photostability, and low dye stability over longer time of operation and storage.
In this thesis we investigate the nonlinear and radiative properties of certain organic
materials and doped polymeric matrix and their possible role in device development
Description:
International School of Photonics, Cochin University of Science & Technology
Sajimol Augustine, M; Dr.Jayalekshmi, S(Cochin University Of Science And Technology, December 20, 2012)
[+]
[-]
Abstract:
Fluorescence is a powerful tool in biological research, the relevance of
which relies greatly on the availability of sensitive and selective fluorescent
probes. Nanometer sized fluorescent semiconductor materials have attracted considerable attention in recent years due to the high luminescence intensity, low
photobleaching, large Stokes’ shift and high photochemical stability. The optical
and spectroscopic features of nanoparticles make them very convincing
alternatives to traditional fluorophores in a range of applications. Efficient surface
capping agents make these nanocrystals bio-compatible. They can provide a novel
platform on which many biomolecules such as DNA, RNA and proteins can be
covalently linked. In the second phase of the present work, bio-compatible,
fluorescent, manganese doped ZnS (ZnS:Mn) nanocrystals suitable for bioimaging
applications have been developed and their cytocompatibility has been
assessed. Functionalization of ZnS:Mn nanocrystals by safe materials results in
considerable reduction of toxicity and allows conjugation with specific
biomolecules. The highly fluorescent, bio-compatible and water- dispersible
ZnS:Mn nanocrystals are found to be ideal fluorescent probes for biological
labeling
Description:
Department of Physics, Cochin University of Science and
Technology
Sabir, M; Dr.Babu, Joseph K(Cochin University of Science and Technology, 1978)
[+]
[-]
Abstract:
The present thesis deals with the studies on certain aspects of pathological higher field theories .It brings to light some new abnormalities and new samples of abnormal theories and also puts forward a novel approach towards the construction of trouble free theories
Description:
Department of Science, Cochin University of Science and Technology
Sini, P J; Dr.Saramma, A V(Cochin University of Science and Technology, February , 2012)
[+]
[-]
Abstract:
Considering the importance of diversity of micro algae in our ecosystem and new invasion of many organisms, an attempt was made to monitor the Cochin estuary along the south west coast of India for the qualitative distribution of phytoplankton and to study the growth kinetics and allelopathic effect of the phaeocystis sp. Isolated from the cochin estuary. Phaeocystis blooms are common only in high latitude environments and they rarely occur in low latitude environments such as tropics and subtropics. As phaeocystis is grouped under harmful alga ,in the present study the factors causing the blooms formation in the ecosystem. The nutrient concentration of the water body along with other physiochemical parameters that includes temperature salinity and ph play an important role in triggering the bloom of phaeocystis .The phaeocystis harbor specific bacterial flora associated with it and they exert an important role in the growth ,haemolytic activity and the bloom phases of the alga. The harmful alga mainly depends on the production of alleopathic compounds for the establishment of bloom in the marine environments .These physiological properties of the phaecystis were considered for the study, along with the role of nutrients in the allelopathic and hemolytic activity
Description:
Department of Marine Biology,Microbiology and Biochemistry
School of Marine Sciences, Cochin University of Science and Technology
Gregorios, Mathew; Dr. Jacob, Philip(Cochin University of Science and Technology, December , 1998)
[+]
[-]
Abstract:
In this thesis, we present the results of our investigations on the photoconducting
and electrical switching properties of selected chalcogenide glass systems. We have used
XRD and X-ray photoelectron spectroscopy (XPS) analysis for confinuing the amorphous
nature of these materials and for confirming their constituents respectively.Photoconductivity is the enhancement in electrical conductivity of materials
brought about by the motion of charge carriers excited by absorbed radiation. The
phenomenon involves absorption, photogeneration, recombination and transport processes
and it gives good insight into the density of states in the energy gap of solids due to the
presence of impurities and lattice defects. Photoconductivity measurements lead to the
determination of such important parameters as quantum efficiency, photosensiti\'ity,
spectral sensitivity and carrier lifetime. Extensive research work on photoconducting
properties of amorphous semiconductors has resulted in the development of a variety of
very sensitive photodetectors. Photoconductors are finding newer and newer uses eyery
day. CdS, CdSe. Sb2S3, Se, ZnO etc, are typical photoconducting materials which are used
in devices like vidicons, light amplifiers, xerography equipment etc.Electrical switching is another interesting and important property possessed by
several Te based chalcogenides. Switching is the rapid and reversible transition between a
highly resistive OFF state, driven by an external electric field and characterized by a
threshold voltage, and a low resistivity ON state, Switching can be either threshold type
or memory type. The phenomenon of switching could find applications in areas like
infonnation storage, electrical power control etc. Investigations on electrical switching in
chalcogenide glasses help in understanding the mechanism of switching which is
necessary to select and modify materials for specific switching applications.Analysis of XRD pattern gives no further infonuation about amorphous materials
than revealing their disordered structure whereas x-ray photoelectron spectroscopy,XPS)
provides information about the different constituents present in the material. Also it gives binding energies (b.e.) of an element in different compounds and hence b.e. shift from the
elemental form.Our investigations have been concentrated on the bulk glasses, Ge-In-Se, Ge-Bi-Se
and As-Sb-Se for photoconductivity measurements and In-Te for electrical switching. The
photoconducting properties of Ge-Sb-Se thin films prepared by sputtering technique have
also been studied. The bulk glasses for the present investigations are prepared by the melt
quenching technique and are annealed for half an hour at temperatures just below their
respective glass transition temperatures. The dependence of photoconducting propenies on
composition and temperature are investigated in each system. The electrical switching
characteristics of In-Te system are also studied with different compositions and by varying
the temperature.
Description:
Department of Instrumentation,
Cochin University of Science and Technology
Sreekanth, Varma J; Dr.Jayalekshmi, S(Cochin University of Science and Technology, September , 2012)
[+]
[-]
Abstract:
Light emitting polymers (LEP) have drawn considerable attention because of their numerous potential applications in the field of optoelectronic devices. Till date, a large number of organic molecules and polymers have been designed and devices fabricated based on these materials. Optoelectronic devices like polymer light emitting diodes (PLED) have attracted wide-spread research attention owing to their superior properties like flexibility, lower operational power, colour tunability and possibility of obtaining large area coatings. PLEDs can be utilized for the fabrication of flat panel displays and as replacements for incandescent lamps. The internal efficiency of the LEDs mainly depends on the electroluminescent efficiency of the emissive polymer such as quantum efficiency, luminance-voltage profile of LED and the balanced injection of electrons and holes. Poly (p-phenylenevinylene) (PPV) and regio-regular polythiophenes are interesting electro-active polymers which exhibit good electrical conductivity, electroluminescent activity and high film-forming properties. A combination of Red, Green and Blue emitting polymers is necessary for the generation of white light which can replace the high energy consuming incandescent lamps. Most of these polymers show very low solubility, stability and poor mechanical properties. Many of these light emitting polymers are based on conjugated extended chains of alternating phenyl and vinyl units. The intra-chain or inter-chain interactions within these polymer chains can change the emitted colour. Therefore an effective way of synthesizing polymers with reduced π-stacking, high solubility, high thermal stability and high light-emitting efficiency is still a challenge for chemists. New copolymers have to be effectively designed so as to solve these issues. Hence, in the present work, the suitability of a few novel copolymers with very high thermal stability, excellent solubility, intense light emission (blue, cyan and green) and high glass transition temperatures have been investigated to be used as emissive layers for polymer light emitting diodes.
Description:
Division for Research in Advanced Materials
Department of Physics, Cochin University of Science and Technology
Shynu, S V; Vasudevan, K(Cochin University of Science & Technology, October , 2006)
[+]
[-]
Abstract:
In this work,we investigate novel designs of compact electronically reconfigurable dual frequency microstrip antennas with a single feed,operating mainly in L-band,without using any matching networks and complicated biasing circuitry.These antennas have been designed to operate in very popular frequency range where a great number of wireless communication applications exist.Efforts were carried out to introduce a successful,low cost reconfigurable dual-frequency microstrip antenna design to the wireless and radio frequency design community.
Description:
Department of Electronics,
Cochin University of Science and Technology
Indu Sebastian; Dr. Sheenu Thomas(Cochin University of Science and Technology, August 10, 2014)
[+]
[-]
Abstract:
Among various optical sensing schemes, infrared spectroscopy is a powerful tool for detecting and determining the composition of complex organic samples since vibrational finger prints of all biomolecules and organic species are located in this window. This spectroscopic technique is simple, reliable, fast, non-destructive, cost-effective while having low sensitivity. Use of metallic nanoparticles in association with a good IR transparent sensing substrate, is one of the promising solutions to enhance the sensitivity.
Chalcogenide glasses are promising substrate material because of their extended optical transmission window starting from the visible to the far infrared range up to 20 μm, high refractive index usually between 2 and 3 and high optical nonlinearity, which make them good candidates as IR sensors and optical ultrafast nonlinear devices. These glasses are favorable sensor materials for the infrared spectral range because of their high IR transparency to allow for low optical loss at wavelengths corresponding to the characteristic optical absorption bands of organic molecules, high refractive index for tight confinement of optical energy within the resonator structure, processibility into thin film form, chemical compatibility for adhesion of silver nano particles and thin films and resistance to the chemical environment to be sensed. Molecules adsorbed to silver island structures shows enhanced IR absorption spectra and the extent of enhancement is determined by many factors such as the size, density and morphology of silver structures, optical and dielectric properties of the substrate material etc.
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.
Sreevalsa, V G; Dr.Jayalekshmi, S(Cochin University Of Science And Technology, November , 2012)
[+]
[-]
Abstract:
Organic crystals possess extremely large optical nonlinearity compared
to inorganic crystals. Also organic compounds have the amenability for
synthesis and scope for introducing desirable characteristics by inclusions. A
wide variety of organic materials having electron donor and acceptor groups,
generate high order of nonlinearity. In the present work, a new nonlinear optical crystal, L-citrulline oxalate (LCO) based on the aminoacid L-citrulline was grown using slow evaporation technique. Structural characterization was carried out by single crystal XRD. It crystallizes in the noncentrosymmetric, orthorhombic structure with space group P21 P21 P21. Functional groups present in the sample were identified by Fourier transform infra red (FTIR) and FT-Raman spectral analysis. On studying the FTIR and Raman spectra of the precursors L-citrulline and oxalic acid, used for growing L-citrulline oxalate crystal, it is found that the
significant peaks of the precursors are present in the spectra of the L-citrulline
oxalate crystal . This observation along with the presence of NH3
+ group in the spectra of L-citrulline oxalate, confirms the formation of the charge
transfer complex
Description:
Department of Physics, Cochin University of Science and Technology
Jeeju, P P; Dr.Jayalekshmi, S(Cochin University of Science and Technology, June , 2012)
[+]
[-]
Abstract:
The present work deals with investigations on some technologically important polymer nanocomposite films and semi crystalline polypyrrole films.The work presented in the thesis deals with the realization of novel polymer nanocomposites with enhanced functionalities and prospects of applications in the fields related to nanophotonics. The development of inorganic/polymer nanocomposites is a rapidly expanding multidisciplinary research area with profound industrial applications. The incorporation of suitable inorganic nanoparticles can endow the resulting nanocomposites with excellent electrical, optical and mechanical properties.
The first chapter gives a general introduction to nanotechnology, nanocomposites and conducting
polymers. It also emphasizes the significance of ZnO among other semiconductor materials, which forms the inorganic filler in the polymer nanocomposites of the present study. This chapter also gives general ideas on the properties and applications of conducting polymers with special reference to polypyrrole. The objectives of the present investigations are also clearly addressed in this chapter.
The second chapter deals with the theoretical aspects and details of all the experimental techniques used in the present work for the synthesis of polymer nanocomposites and polypyrrole samples and their various characterizations. Chapter 3 is based on the preparation and properties of ZnO/Polystyrene nanocomposite film samples. The optical properties of these nanocomoposite films are discussed in detail.Chapter 4 deals with the detailed investigations on the dependence of the optical properties of ZnO/PS nanocomposite films on the size of the nanostructured ZnO filler material. The excellent UV shielding properties of these nanocomposite films form the highlight of this chapter. Chapter 5 gives a detailed analysis of the nonlinear optical properties of ZnO/PS nanocomposite films using Z scan technique. The effect of ZnO particle size in the composite films on the nonlinear properties is discussed. The present study involves two phases of research activities. In the first phase, the linear and nonlinear optical properties of ZnO/polymer nanocomposites are investigated in detail. The second phase of work is centered on the synthesis and related studies on highly crystalline polypyrrole films.
In the present study, nanosized ZnO is synthesized using wet chemical method at two different temperatures
Description:
Department of Physics,
Cochin University of Science and Technology,
Ahmed Yasir,Vakayil; Mohan Das,P N; Mohammed Yusuff, K K(Department of Applied Chemistry, 2001)
[+]
[-]
Abstract:
Titania is a versatile metal oxide with multiple applications. Titania supported catalysts are reported to be much more active compared to conventional silica or alumina supported ones in some reactions. TiO2 (anatase) having high surface area, with better crystallinity and high onset temperature of rutilation can be prepared by thermal hydrolysis of titanyl sulfate solution under controlled conditions. Calcinations at 350oC for 6 hrs were necessary to crystallize anatase. Method of preparation and percentage of the loaded metal oxides have greater influence on surface area. Drastic decrease in surface area was observed upon rutilation. Rutilation started at different temperatures depending on the metal oxide and the method of preparation. TiO2 should be characterized with high surface area, phase purity and high onset temperature of rutilation.Which should be well above the optimum temperature of a designated reaction in which it is employed as a catalyst. Variation in physical properties, depending upon the method of preparation is greater in TiO2 supported catalysts. Methanation activity was found to be highly dependent on nickel concentration present on the surface of the pellets. The methanation activity is strongly influenced by support material. The rate and turn over frequency of methanation and toluene oxidation activity of these catalysts are also equally important from an industrial point of view.
Manikandan,R; Dr.Krishnamoorthy,A(Cochin University Of Science And Technology, October 24, 2013)
[+]
[-]
Abstract:
In this thesis the queueing-inventory models considered are analyzed
as continuous time Markov chains in which we use the tools such as matrix
analytic methods. We obtain the steady-state distributions of various
queueing-inventory models in product form under the assumption that no
customer joins the system when the inventory level is zero. This is despite
the strong correlation between the number of customers joining the system
and the inventory level during lead time. The resulting quasi-birth-anddeath
(QBD) processes are solved explicitly by matrix geometric methods
Description:
Department of Mathematics
Cochin University of Science and Technology
Manju Dominic; Dr C.G. Nandakumar(Cochin University of Science and Technology, February 12, 2016)
[+]
[-]
Abstract:
Composite materials have emerged as a superior structural material having application in
all spheres of life. These have applications in every sector and essentially in marine
environment, where high strength to weight ratio and noncorrosive nature of the material
has great importance. Subsequently there has been a major shift in use of structural
materials from steel to composite materials in marine structures. Composite materials are
engineered materials made from two or more constituent materials that are combined at a
macroscopic level to produce a material with characteristics different from the individual
components. When both the matrix and fibre are not of metallic origin, such composites
are called as nonmetallic composites. Glass Fibre Reinforced Polymers (GFRP), Carbon
Fibre Reinforced Polymers (CFRP) and Aramid Fibre Reinforced Polymers (AFRP) are
common nonmetallic composite materials used for marine structural applications. These
are used in laminate form in ship hull construction.In the present study, a design philosophy based on strength and sustainability of
composite laminates has been proposed for selection of composites for ship hull
construction. For this purpose, an index based on strength of composite laminates and an
index based on sustainability of composites has been tabulated and materials need to be
selected based on these indices. Both the indices had been constructed as a composite
indicator. Index based on strength called as ‘Strength Index’ has been developed based on
the index values of various strength parameters. Index based on sustainability called as
‘Sustainability index’ has been developed based on the index values of the composites
based on the environmental impact of various phases of a ship’s life cycle. Nine non
metallic composites have been considered in the present study. Accordingly strength
parameters identified are bending strength, buckling strength and impact strength have
been found out. Environmental impact during the manufacturing phase and disposal phase
of composites has been found out. Based on these index values, indices based on strength
and sustainability has been constructed respectively. Based on these indices, ranks have
been assigned in such a way that, lower rank corresponds to higher strength and lower
environmental impact. This also means lower the rank, higher the acceptability of the composite laminates. Using these two indices a two dimensional assessment of
composites has been conducted. In this study both the indices have been superimposed to
get strength index versus sustainability index plot. Analysis of this plot is the core of the
design philosophy, ‘Design for strength and sustainability’. According to this design
philosophy, the composite which has the least strength index and sustainability index
rank should be selected for designing so that the structure will be strong and at the same
time have a low impact on the environment. This procedure can be extended to any
number of composites in the marine area or to composites that has application in other
areas.
Nandagopan, O R; Dr.Nandakumar, C G(Cochin University of Science and Technology, November , 2010)
[+]
[-]
Abstract:
The study envisaged herein contains the numerical investigations on Perforated Plate
(PP) as well as numerical and experimental investigations on Perforated Plate with Lining
(PPL) which has a variety of applications in underwater engineering especially related to
defence applications. Finite element method has been adopted as the tool for analysis of
PP and PPL. The commercial software ANSYS has been used for static and free
vibration response evaluation, whereas ANSYS LS-DYNA has been used for shock
analysis. SHELL63, SHELL93, SOLID45, SOLSH190, BEAM188 and FLUID30 finite
elements available in the ANSYS library as well as SHELL193 and SOLID194 available
in the ANSYS LS-DYNA library have been made use of. Unit cell of the PP and PPL
which is a miniature of the original plate with 16 perforations have been used. Based
upon the convergence characteristics, the utility of SHELL63 element for the analysis of
PP and PPL, and the required mesh density are brought out. The effect of perforation,
geometry and orientation of perforation, boundary conditions and lining plate are
investigated for various configurations. Stress concentration and deflection factor are
also studied. Based on these investigations, stadium geometry perforation with horizontal
orientation is recommended for further analysis.Linear and nonlinear static analysis of PP and PPL subjected to unit normal pressure has
been carried out besides the free vibration analysis. Shock analysis has also been carried
out on these structural components. The analytical model measures 0.9m x 0.9m with
stiffener of 0.3m interval. The influence of finite element, boundary conditions, and lining plate on linear static response has been estimated and presented. Comparison of
behavior of PP and PPL in the nonlinear strain regime has been made using geometric
nonlinear analysis. Free vibration analysis of the PP and PPL has been carried out ‘in
vacuum’ condition and in water backed condition, and the influence of water backed
condition and effect of perforation on natural frequency have been investigated.Based upon the studies on the vibration characteristics of NPP, PP and PPL in water
backed condition and ‘in vacuum’ condition, the reduction in the natural frequency of the
plate in immersed condition has been rightly brought out. The necessity to introduce the
effect of water medium in the analysis of water backed underwater structure has been
highlighted.Shock analysis of PP and PPL for three explosives viz., PEK, TNT and C4 has been
carried out and deflection and stresses on plate as well as free field pressure have been
estimated using ANSYS LS-DYNA. The effect of perforations and the effect of lining
plate have been predicted. Experimental investigations of the measurement of free field
pressure using PPL have been conducted in a shock tank. Free field pressure has been
measured and has been validated with finite element analysis results. Besides, an
experiment has been carried out on PPL, for the comparison of the static deflection
predicted by finite element analysis.The distribution of the free field pressure and the estimation of differential pressure from
experimentation and the provision for treating the differential pressure as the resistance,
as a part of the design load for PPL, has been brought out.
Description:
Dept. of Ship Technology,
Cochin University of Science and
Technology
Neethu Sundaresan; C K S Pillai(RRL,CUSAT, April , 2006)
[+]
[-]
Abstract:
Liquid Crystalline DNA is emerging as an active area of research, due to its potential applications in diverse fields, ranging from nanoelectronics to therapeutics. Since, counter ion neutralization is an essential requirement for the expression of LC DNA, and the present level of understanding on the LC phase behavior of high molecular weight DNA is inadequate, a thorough investigation is required to understand the nature and stability of these phases under the influence of various cationic species. The present study is, therefore mainly focused on a comparative investigation of the effect of metal ions of varying charge, size, hydration and binding modes on the LC phase behavior of high molecular weight DNA. The main objectives of the works are investigations on the induction and stabilization of LC phases of high molecular weight DNA by alkali metal ions, investigations on the induction and stabilization of LC phases of high molecular weight DNA by alkaline earth metal ions, effects of multivalent, transition and heavy metal ions on the LC phase behavior of high molecular weight DNA and investigations on spermine induced LC behavior of high molecular weight DNA in the presence of alkali and alkaline earth metal ions.
The critical DNA concentration (CD) required for the expression of LC phases, phase transitions and their stability varied considerably when the binding site of the metal ions changed from phosphate groups to the nitrogenous bases of DNA, with Li+ giving the highest stability. Multiple LC phases with different textures, sometimes diffused and unstable or otherwise mainly distinct and clear, were observed on mixing metal ions with DNA solutions, which in turn depended on the charge, size, hydration factor, binding modes, concentration of the metal ions and time. Molecular modeling studies on binding of selected metal ions to DNA supported the experimental findings
Gopikakumari, R; Dr.Sreedhar, C S(Cochin University Of Science And Technology, July 31, 1998)
[+]
[-]
Abstract:
This thesis is an outcome of the investigations carried out on the development of an
Artificial Neural Network (ANN) model to implement 2-D DFT at high speed. A new
definition of 2-D DFT relation is presented. This new definition enables DFT computation
organized in stages involving only real addition except at the final stage of computation. The
number of stages is always fixed at 4. Two different strategies are proposed. 1) A visual
representation of 2-D DFT coefficients. 2) A neural network approach.
The visual representation scheme can be used to compute, analyze and manipulate 2D
signals such as images in the frequency domain in terms of symbols derived from 2x2
DFT. This, in turn, can be represented in terms of real data. This approach can help analyze
signals in the frequency domain even without computing the DFT coefficients.
A hierarchical neural network model is developed to implement 2-D DFT. Presently,
this model is capable of implementing 2-D DFT for a particular order N such that ((N))4 = 2.
The model can be developed into one that can implement the 2-D DFT for any order N upto a
set maximum limited by the hardware constraints. The reported method shows a potential in
implementing the 2-D DF T in hardware as a VLSI / ASIC
Description:
Department of Electronics,
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.
Krishnan Nair, P R; Nandakumaran, V M(Cochin University of Science and Technology, October , 1999)
[+]
[-]
Abstract:
This thesis is a study of discrete nonlinear systems represented by one dimensional mappings.As one dimensional interative maps represent Poincarre sections of higher dimensional flows,they offer a convenient means to understand the dynamical evolution of many physical systems.It highlighting the basic ideas of deterministic chaos.Qualitative and quantitative measures for the detection and characterization of chaos in nonlinear systems are discussed.Some simple mathematical models exhibiting chaos are presented.The bifurcation scenario and the possible routes to chaos are explained.It present the results of the numerical computational of the Lyapunov exponents (λ) of one dimensional maps.This thesis focuses on the results obtained by our investigations on combinations maps,scaling behaviour of the Lyapunov characteristic exponents of one dimensional maps and the nature of bifurcations in a discontinous logistic map.It gives a review of the major routes to chaos in dissipative systems,namely, Period-doubling ,Intermittency and Crises.This study gives a theoretical understanding of the route to chaos in discontinous systems.A detailed analysis of the dynamics of a discontinous logistic map is carried out, both analytically and numerically ,to understand the route it follows to chaos.The present analysis deals only with the case of the discontinuity parameter applied to the right half of the interval of mapping.A detailed analysis for the n –furcations of various periodicities can be made and a more general theory for the map with discontinuities applied at different positions can be on a similar footing
Nandini Menon,N; Dr.Ravindranatha Menon,N(Cochin University of Science & Technology, April , 1997)
[+]
[-]
Abstract:
The thesis deals with different aspects connected with the distribution and toxicity of PHC in crude oils in the aquatic environment and marine molluscs. Information has been gathered and presented on the present status of research in the field based on a thorough review of recent literature. It is seen from the literature that the resident time of PHC becomes lesser and lesser when crude oil is discharged in large quantities into the coastal waters where excess oxygenation light penetration, temperature availability and strong tidal currents persist. This results in the reduction of the onslaught of oil pollution. This probably shows that taxic insult of crude oil in tropical shores will be relatively lesser than that occurring in temperate and boreal waters. However, there is no record of major episodal oil pollution comparable in quantum and extent to that of Torrey Canyon or Amoco Cadiz which prevents a more reliable analysis on the issue. Considerable controversy exists on the method of estimation of PHC in seawater. However, Ultra-violet fluorescence spectroscopy has been widely recommended as an analytical tool for the determination of total hydrocarbons. Similarly representation of values as chrysene equivalents has been recognised as the most reliable method of Quantum representation.
Description:
Division of Marine Biology, Microbiology and Biochemistry, school of Marine Sciences, Cochin University of Science and Technology
Nirmala, Paul; Dr.Krishna Pillai, M G(Cochin University Of Science And Technology, December 2, 1981)
[+]
[-]
Abstract:
The thesis is a report of the attempts made to
prepare semiconducting and dielectric thin films and to
study their electrical properties. It consists of (i)
studies on the preparation and electrical characteristics
of compound semiconductor thin films of silver sulphide
and ferric hydroxide, and (ii) investigations on the electrical
and dielectric properties of plasma polymerized
thin films of para-toluidine element
Description:
Department
of Physics,Cochin University Of Science And Technology
Matlrew, George; Dr.Anantharaman, M R(Cochin University of Science & Technology, February , 2004)
[+]
[-]
Abstract:
Magnetism and magnetic materials have been an ever-attractive
subject area for engineers and scientists alike because of its versatility in
finding applications in useful devices. They find applications in a host of
devices ranging from rudimentary devices like loud speakers to sophisticated
gadgets like waveguides and Magnetic Random Access Memories (MRAM).The one and only material in the realm of magnetism that has been at the
centre stage of applications is ferrites and in that spinel ferrites received the
lions share as far as practical applications are concerned.It has been the endeavour of scientists and engineers to remove
obsolescence and improve upon the existing so as to save energy and
integrate in to various other systems. This has been the hallmark of material
scientists and this has led to new materials and new technologies.In the field of ferrites too there has been considerable interest to
devise new materials based on iron oxides and other compounds. This means
synthesising ultra fine particles and tuning its properties to device new
materials. There are various preparation techniques ranging from top- down
to bottom-up approaches. This includes synthesising at molecular level, self
assembling,gas based condensation. Iow temperature eo-precipitation, solgel
process and high energy ball milling. Among these methods sol-gel
process allows good control of the properties of ceramic materials. The
advantage of this method includes processing at low temperature. mixing at
the molecular level and fabrication of novel materials for various devices.Composites are materials. which combine the good qualities of one
or more components. They can be prepared in situ or by mechanical means
by the incorporation of fine particles in appropriate matrixes. The size of the
magnetic powders as well as the nature of matrix affect the processability
and other physical properties of the final product. These plastic/rubber
magnets can in turn be useful for various applications in different devices.
In applications involving ferrites at high frequencies, it is essential that the
material possesses an appropriate dielectric permittivity and suitable
magnetic permeability. This can be achieved by synthesizing rubber ferrite
composites (RFC's). RFCs are very useful materials for microwave
absorptions. Hence the synthesis of ferrites in the nanoregirne.investigations on their size effects on the structural, magnetic, and electrical
properties and the incorporation of these ferrites into polymer matrixes
assume significance.In the present study, nano particles of NiFe204, Li(!5Fe2S04 and
Col-e-O, are prepared by sol gel method. By appropriate heat treatments,
particles of different grain sizes are obtained. The structural, magnetic and
electrical measurements are evaluated as a function of grain size and
temperature. NiFel04 prepared in the ultrafine regime are then incorporated
in nitrile rubber matrix. The incorporation was carried out according to a
specific recipe and for various loadings of magnetic fillers. The cure
characteristics, magnetic properties, electrical properties and mechanical
properties of these elastomer blends are carried out. The electrical
permittivity of all the rubber samples in the X - band are also conducted.
Description:
Department of Physics,
Cochin University of Science & Technology
Mathew, George; Dr.Anantharaman, M R(Cochin University Of Science And Technology, February 16, 2004)
[+]
[-]
Abstract:
In the present study, nano particles of NiFe3O4, I_.l()5Feg5O4 and
CoFegO4 are prepared by sol gel method. By appropriate heat treatments,
particles of different grain sizes are obtained. The structural, magnetic and
electrical measurements are evaluated as a function of grain size and
temperature. NiFe3O4 prepared in the ultrafine regime are then incorporated
in nitrile rubber matrix. The incorporation was carried out according to a
specific recipe and for various loadings of magnetic fillers. The cure
characteristics, magnetic properties, electrical properties and mechanical
properties of these elastomer blends are carried out. The electrical
permittivity of all the rubber samples in the X — band are also conducted
Description:
Department of Physics
Cochin University of Science & Technology
Sagar, S; Dr.Anantharaman, M R(Cochin University of Science & Technology, August , 2010)
[+]
[-]
Abstract:
This thesis lays importance in the investigation on the multiferroic and
thermooelectric properties of selected representatives of low bandwidth and
intermediate band width manganites. The first candidate, Strontium doped Gd manganite, is prepared by wet solid state reaction method and the second
candidate, Na doped La manganite, by citrate gel method. In addition to the above
mentioned properties, magneto resistance and dielectric properties are
investigated. Using dielectric spectroscopic the dispersion parameters are
correlated to the relaxation mechanisms and an attempt is made to obtain the grain
and grain boundary contribution to the impedance of the sample through
impedance spectroscopy studies.
Description:
Department of Physics,
Cochin University of Science & Technolog
Palson,T I; Dr.Joy, George(Cochin University Of Science And Technology, February 16, 1987)
[+]
[-]
Abstract:
The work reported in this thesis is the preparation,
and the structural, electrical and optical properties
of reactively evaporated lead sulphide and tin telluride
thin films. The three temperature method had been used
for the preparation of these semiconductor thin films.
In this preparation technique constituent elements are
evaporated from separate sources with the substrate kept
at a particular temperature. when one of the constituent
element is a gas near room temperature, the method is
often called reactive evaporation. It has been found for
many materials that a stoichiometric interval exists with
a limited range of flux and substrate temperature. Usually
this technique is used for the preparation of thin films of
high melting point compounds or of materials which decompose
during evaporation. Tin telluride and lead sulphide are
neither high melting point materials nor do they decompose
on melting. But even than reactive evaporation offers the
possibility of changing the ratios of the flux of the constituent
elements within a wide range and studying its
effect on the properties of the films
Description:
Department of Physics, Cochin
University of Science and Technology
Sarin, V P; Dr.Vasudevan, K(Cochin University of Science and Technology, January , 2012)
[+]
[-]
Abstract:
With the recent progress and rapid increase in mobile terminals, the design of
antennas for small mobile terminals is acquiring great importance. In view of this
situation, several design concepts are already been addressed by the scientists and
engineers. Compactness and efficiency are the major criteria for mobile terminal
antennas. The challenging task of the microwave scientists and engineers is to device
compact printed radiating systems having broadband behavior, together with good
efficiency. Printed antenna technology has received popularity among antenna
scientists after the introduction of microstrip antenna in 1970s. The successors in this
kind such as printed monopoles and planar inverted F are also equally important.
Scientists and Engineers are trying to explore this technology as a viable coast
effective solution for forthcoming microwave revolution. The transmission line
perspectives of antennas are very interesting. The concept behind any
electromagnetic radiator is simple. Any electromagnetic system with a discontinuity
is radiating electromagnetic energy. The size, shape and the orientation of the
discontinuities controls the radiation characteristics of the system such as radiation
pattern, gain, polarization etc. It can be either resonant or non resonant structure.
Microstrip antennas are suitable for wireless applications due to their low cost,
high gain and ease of fabrication. But the major disadvantage of micro strip antennas is
their inherent narrow bandwidth. A lot of techniques are introduced by the researchers
all over the world to enhance the bandwidth of micro strip patch antennas. The thesis
addresses an attempt to enhance the bandwidth of micro strip patch antennas by
incorporating impedance matching strip as a part of the micro strip patch antenna. The
first part of the thesis deals with the broadband operation of the tilted square slot and
polygonal slot loaded square micro strip patch antennas. The resonant mechanisms are
clearly mentioned using the simulation and experimental studies. The bandwidth of the
polygonal slotted broadband patch antenna is again enhanced by implementing an Lstrip
feed mechanism. In the second major part of the thesis, a novel gain enhancement
technique for single band and broadband square micro strip patch antennas is achieved
by implementing offset stacked configurations.
Description:
Department of Electronics
Cochin University of Science and Technology
Sarin, V.P; Dr. K. Vasudevan(Cochin University of Science and Technology, January 14, 2012)
[+]
[-]
Abstract:
With the recent progress and rapid increase in mobile terminals, the design of
antennas for small mobile terminals is acquiring great importance. In view of this
situation, several design concepts are already been addressed by the scientists and
engineers. Compactness and efficiency are the major criteria for mobile terminal
antennas. The challenging task of the microwave scientists and engineers is to device
compact printed radiating systems having broadband behavior, together with good
efficiency. Printed antenna technology has received popularity among antenna
scientists after the introduction of microstrip antenna in 1970s. The successors in this
kind such as printed monopoles and planar inverted F are also equally important.
Scientists and Engineers are trying to explore this technology as a viable coast
effective solution for forthcoming microwave revolution. The transmission line
perspectives of antennas are very interesting. The concept behind any
electromagnetic radiator is simple. Any electromagnetic system with a discontinuity
is radiating electromagnetic energy. The size, shape and the orientation of the
discontinuities controls the radiation characteristics of the system such as radiation
pattern, gain, polarization etc. It can be either resonant or non resonant structure.
Vasudevan, K; Dr.Nair, K G(Cochin University of Science and Technology, April 19, 1982)
[+]
[-]
Abstract:
Antennas play an important role in determining
the characteristics of any electronic system which depends
on free space as the propagation medium. Basically, an
antenna can be considered as the connecting link between
free space and the transmitter or receiver. For radar and
navigational purposes the directional properties of an
antenna is its most basic requirement as it determines the
distribution of radiated energy. Hence the study of directional properties of antennas has got special significance
and several useful applications.
Description:
Department of Physics, Cochin University of Science and Technology
Joseph, V P; Dr.Mathew, K T(Cochin University of Science And Technology, July , 1999)
[+]
[-]
Abstract:
Investigations on the design and development of certain new hollow
dielectric hom antennas of rectangular cross section have been carried out. The main
shortcoming of the existing ordinary hollow dielectric hom antenna (HDH) is the
abrupt discontinuity at the feed-end. A new launching technique using a dielectric rod is
introduced to overcome this limitation. Also a strip loading technique is employed for
further modification of the antenna. Radiation parameters of new I-IDH antennas of Eplane
sectoral, H-plane sectoral and pyramidal types were studied and are found to be
very attractive. Theoretical approach based on Marcatili’s principle and two aperture
theory along with diffraction theory and image theory is used to support the experimental
findings. The HDH is considered as solid horn of effective dielectric constant and the
aperture field is evaluated. The antenna is excited by the open waveguide in the dominant
TE1o mode and so the existence of any hybrid mode is mled-out. The theoretical results
are observed to be in good agreement with the experimental results.
Description:
Department of Electronics, Cochin University of Science and Technology
Gopikrishna, M; Dr.Aanandan, C K(Cochin University of Science & Technology, July , 2010)
[+]
[-]
Abstract:
A major challenge in the transmission of narrow pulses is the radiation characteristics
of the antenna. Designing the front ends for UWB systems pose challenges
compared to their narrow and wide band counterparts because in addition to
having electrically small size, high efficiency and band width, the antenna has
to have excellent transient response. The present work deals with the design
of four novel antenna designs- Square Monopole, Semi-Elliptic Slot, Step and
Linear Tapered slot - and an assay on their suitability in UWB Systems. Multiple
resonances in the geometry are matched to UWB by redesigning the ground-patch
interfaces. Techniques to avoid narrow band interference is proposed in the
antenna level and their effect on a nano second pulse have also been investigated.
The thesis proposes design guidelines to design the antenna on laminates of any
permittivity and the analyzes are complete with results in the frequency and time
domains.
Description:
Department of Electronics,
Cochin University of Science and Technology
Jesty, Thomas; Surender, G D; Reddy, M L P(RRL (CSIR), 2000)
[+]
[-]
Abstract:
The thesis entitled INVESTIDGATIONS ON THE RECOVERY OF TITANIUM VANADIUM AND IRON VALUES FROM THE WASTE CHILORIDE LIQUORS OF TITANIA INDUSTRY embodies the results of the investigations carried out on the solvent extraction separation of iron (III) vanadium(V) and titanium (IV) chlorides from the waste chloride liquors of titanium minerals processing industry by employing tributylphosphate (TBT) as an extractant. The objective of this study is to generate the knowledge base to achieve the recovery of iron, vanadium and titanium cvalues from multi- metal waste chloride liquors originating from ilmenite mineral beneficiation industries through selective separation and value added material development
Rani, Pavithran; Reddy, M L P(Chemical Science Division RRL (CSIR), March , 2005)
[+]
[-]
Abstract:
The thesis entitled “ Investigations on the solvent extraction and luminescence of lanthanoids with mixtures of heterocyclic β-diketone S and various neutral oxo-donors” embodies the results of investigations carried out on the solvent extraction of trivalent lanthanoids with various heterocyclic β-diketones in the presence and absence of neutral oxo-donors and also on the luminescent studies of Eu3+-heterocyclic β-diketonate complexes with Lewis bases. The primary objective of the present work is to generate the knowledge base, especially to understand the interactions of lanthanoid-heterocyclic β-diketonates with various macrocyclic ligands such as crown ethers and neutral organophosphorus extractants , with a view to achieve better selectivity. The secondary objective of this thesis is to develop novel lanthanoid luminescent materials based on 3-phenyl-4-aroyl-5-isoxazolones and organophosphorus ligands, for use in electroluminescent devices.
In the beginning it describes the need for the development of new mixed-ligand systems for the separation of lanthanoids and the development and importance of novel luminescent lanthanoid- β-diketonate complexes for display devices. The syntheses of various para substituted derivatives of 4-aroyl-5-isoxazolones and their characterization by various spectroscopic techniques are described. It also investigate the solvent extraction behaviour of trivalent lanthanoids with 4-aroyl-5-isoxazolones in the presence and absence of various crown ethers such as 18C6, DC18C6, DB18C6 and B18C6. Elemental analysis, IR and H NMR spectral studies are used to understand the interactions of crown ethers with 4-aroyl-5-isoxazolonate complexes of lanthanoids.
The synergistic extraction of trivalent lanthanoids with sterically hindered 1-phenyl-3-methyl-4-pivaloyl-5-pyrazolone in the presence of various structurally related crown ethers are studied. The syntheses, characterization and photyphysical properties of Eu3+-4-aroyl-5-isoxazolonate complexes in the presence of Lewis bases like trictylphosphine oxide or triphenylphosphine oxide were studied.
Miriam,Paul; Dr.Ravindranatha Menon,N(Cochin University Of Science And Technology, June 5, 2001)
[+]
[-]
Abstract:
The present investigation has addressed the eflects of PHC
contaminated culture medium on the morphology, physiology and
behaviour of shrimps] The shrimp Metapenaeus dobsoni is an important
member of the crustacean animal community abounding the oil
contaminated benthic regions of Cochin backwater system. Since it is
known that true pollutants can disrupt the sustainability of ecosystems by
its eflect on species, populations and communities, a representative
species was used for the study. The results discussed in this work is bound
to help in understanding the ecotoxicant resistance that the animal may
display under toxic conditions compared to aynamic steaay-state systems
in nature
Description:
School of Marine Sciences, Cochin
University of Science and Technology
Paul,Miriam; Dr.Ravindranatha Menon,N(Cochin University of Science & Technology, 2001)
[+]
[-]
Abstract:
The present investigation has addressed the effects of PHC contaminated culture medium on the morphology, physiology and behaviour of shrimps. The shrimp Metapenaeus dobsoni is an important member of the crustacean animal community abounding the oil contaminated benthic regions of Cochin backwater system. Since it is known that true pollutants can disrupt the sustainability of ecosystems by its effect on species, populations and communities,a representative species was used for the study. The results discussed in this work is bound to help in understanding the ecotoxicant resistance that the animal may display under toxic conditions compared to dynamic steady-state systems in nature.
Description:
Division of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology
Dhiju Das, P. H.; Dr Leela, Edwin(Cochin University of Science and Technology, October , 2015)
[+]
[-]
Abstract:
The study covers theFishing capture technology innovation includes the catching of aquatic
animal, using any kind of gear techniques, operated from a vessel. Utilization
of fishing techniques varies, depending upon the type of fisheries, and can go
from a basic and little hook connected to a line to huge and complex mid water
trawls or seines operated by large fishing vessels.The size and autonomy of a fishing vessel is largely determined by its
ability to handle, process and store fish in good condition on board, and thus
these two characteristics have been greatly influenced by the introduction and
utilization of ice and refrigeration machinery. Other technological developments
especially hydraulic hauling machinery, fish finding electronics and synthetic
twines have also had a major impact on the efficiency and profitability of
fishing vessels.A wide variety of fishing gears and practices ranging from small-scale
artisanal to advanced mechanised systems are used for fish capture in Kerala.
Most important among these fishing gears are trawls, seines, lines, gillnets and
entangling nets and traps The modern sector was introduced in 1953 at
Neendakara, Shakthikulangara region under the initiative of Indo-Norwegian
project (INP). The novel facilities introduced in fishing industry by Indo-
Norwegian project accordingly are mechanically operated new boats with new fishing nets. Soon after mechanization, motorization programme gained
momentum in Kerala especially in Alleppey, Ernakulam and Kollam districts.
Dhannia, T; Dr.Jayalekshmi, S(Cochin University of Science and Technology, January 30, 2012)
[+]
[-]
Abstract:
This thesis Entitled INVESTIGATIONS ON THE STRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF NANOSTRUCTURED CERIUM OXIDE IN PURE AND DOPED FORMS AND ITS POLYMER NANOCOMPOSITES.Synthesis and processing of nanomatelials and nanostmctures are the essential aspects of nanotechnology. Studies on new physical properties and
applications of nanomaterials and nanostructures are possible only when nanostructured materials are made available with desired size, morphology,crystal structure and chemical composition.Recently, several methods have been developed to prepare pure and doped CeO2 powder, including wet chemical synthesis, thermal hydrolysis, flux method, hydrothermal synthesis, gas condensation method, microwave technique etc. In all these, some special reaction conditions, such as high temperature, high pressure, capping agents, expensive or toxic solvents etc. have been involved.Another hi gh-li ght of the present work is room temperature ferromagnetism in cerium oxdie thin films deposited by spray pyrolysis technique.The observation of self trapped exciton mediated PL in ceria nanocrystals is another important outcome of the present study. STE mediated mechanism has been proposed for CeO2 nanocrystals based on the dependence of PL intensity on the annealing temperature. It would be interesting to extent these investigations to the doped forms of cerium oxide and cerium oxide thin
films to get deeper Insight into STE mechanism.Due to time constraints detailed investigations could not be canied out on the preparation and properties of free standing films of polymer/ceria
nanocomposites. It has been observed that good quality free standing films of PVDF/ceria, PS/C61‘l8, PMMA/ceria can be obtained using solution casting technique. These polymer nanocomposite films show high dielectric constant around 20 and offer prospects of applications as gate electrodes in metal-oxide semiconductor devices.
Description:
Division for Research in Advanced Materials,
Department of Physics,
Cochin University of Science and Technology
Dhannia, T; Dr. S. Jayalekshmi(Cochin University of Science and Technology, January 30, 2012)
[+]
[-]
Abstract:
In recent years, nanoscience and nanotechnology has emerged as one of
the most important and exciting frontier areas of research interest in almost all
fields of science and technology. This technology provides the path of many
breakthrough changes in the near future in many areas of advanced technological
applications. Nanotechnology is an interdisciplinary area of research and
development. The advent of nanotechnology in the modern times and the
beginning of its systematic study can be thought of to have begun with a lecture by
the famous physicist Richard Feynman. In 1960 he presented a visionary and
prophetic lecture at the meeting of the American Physical Society entitled “there is
plenty of room at the bottom” where he speculated on the possibility and potential of
nanosized materials.
Synthesis of nanomaterials and nanostructures are the essential aspects of
nanotechnology. Studies on new physical properties and applications of
nanomaterials are possible only when materials are made available with desired
size, morphology, crystal structure and chemical composition. Cerium oxide (ceria)
is one of the important functional materials with high mechanical strength, thermal
stability, excellent optical properties, appreciable oxygen ion conductivity and
oxygen storage capacity. Ceria finds a variety of applications in mechanical
polishing of microelectronic devices, as catalysts for three-way automatic exhaust
systems and as additives in ceramics and phosphors. The doped ceria usually has
enhanced catalytic and electrical properties, which depend on a series of factors
such as the particle size, the structural characteristics, morphology etc. Ceria based
solid solutions have been widely identified as promising electrolytes for
intermediate temperature solid oxide fuel cells (SOFC). The success of many
promising device technologies depends on the suitable powder synthesis
techniques. The challenge for introducing new nanopowder synthesis techniques is to preserve high material quality while attaining the desired composition. The
method adopted should give reproducible powder properties, high yield and must
be time and energy effective. The use of a variety of new materials in many
technological applications has been realized through the use of thin films of these
materials. Thus the development of any new material will have good application
potential if it can be deposited in thin film form with the same properties. The
advantageous properties of thin films include the possibility of tailoring the
properties according to film thickness, small mass of the materials involved and
high surface to volume ratio. The synthesis of polymer nanocomposites is an
integral aspect of polymer nanotechnology. By inserting the nanometric inorganic
compounds, the properties of polymers can be improved and this has a lot of
applications depending upon the inorganic filler material present in the polymer.
Suni, V; Dr.Prathapachandra Kurup,M R(Cochin University of Science and Technology, August 29, 2005)
[+]
[-]
Abstract:
The present work deals with the investigations on sthe structural spectral and magnetic interactions of transition metal complexes of multidentate ligands from D1-2-pyridyl ketone and N(4)-Substituted thiosemicarbazides.Thiosemicarbazones are thiourea derivatives with the general formula R2N—
C(S)—NH—N=CR2. In the solution state, the thiosemicarbazones exhibit the thionethiol tautomerism similar to the keto-enol tautomerism, and in solution state the thiol form predominates and a deprotonation at the thiolate group in alcoholic medium enhances the coordination abilities ofthe thiosemicarbazones.The magnetochemistry of metal complexes of di-2-pyridyl ketone is a current
hot subject of research, which mainly owes to the excellent structural diversity of the complexes ranging from cubanes to clusters, with promising ferromagnetic outputs.Only few efforts were aimed at
the magnetochemistry of metal complexes of thiosemicarbazones, and that too were concerned with the complexes of bisttltioscinicarbazones). However, as far as the monothiosemicarbazones are concerned, the magnetochemistry of transition metal complexes of di-2-pyridyl ketone thiosemicarbazones turned up quite unexplored. Consequently, an investigation into it appeared novel and promising to us and that prompted this study, which can be regarded as the initial step towards exploring the magnetochemistry of thiosemicarbazone complexes, especially of di-2-pyridyl ketone derivatives.We could successfully isolate single crystals suitable for X-ray diffraction for the first three ligands.
To conclude, we have synthesized some new thiosemicarbazones and their transition metal complexes and studied their structural, spectral and magnetic attributes. Some ofthe complexes revealed interesting stereochemistries and possible bridging characteristics with spectroscopic evidences. Unfortunately, single crystal Xray diffraction studies could not be carried out for many of these interesting compounds due to the lack of availability of suitable quality single crystals. However,
the magnetic studies provided support for the proposed stereochemistry giving evidences for their magnetically concentrated nature. The magnetic susceptibilities measured at six different temperatures in the 80-298 K range are fitted into different magnetic equations, which provided an idea about the magnetic behavior of the compounds under study. Some of the copper, oxovanadium, nickel and cobalt
complexes are found to possess anomalous magnetic moments, i.e., they revealed no regular gradation with temperature. However, some other copper complexes are observed to be antiferromagnetic, due to super-exchange pathways. The manganese complexes and one of the cobalt complexes are also observed to be antiferromagnetic in nature. However, some nickel complexes have turned up to be ferromagnetic. Accordingly, the versatile stereoehemistry and magnetic behavior of the complexes
studied, prompt us to conclude that the transition metal complexes of di-2-pyridyl ketone thiosemicarbazones are promising systems for potential magnetic applications.
Description:
Department of Applied Chemistry,Cochin University of Science and Technology
Divya, S; Dr. A. Mujeeb(Cochin University of Science and Technology, May 20, 2015)
[+]
[-]
Abstract:
This Study overviews the basics of TiO2with respect to its structure, properties and applications. A brief account of its structural, electronic and optical properties is provided. Various emerging technological applications utilising TiO2 is also discussed.Till now, exceptionally large number of fundamental studies and application-oriented research and developments has been carried out by many researchers worldwide in TiO2 with its low-dimensional nanomaterial form due to its various novel properties. These nanostructured materials have shown many favourable properties for potential applications, including pollutant photocatalytic decomposition, photovoltaic cells, sensors and so on. This thesis aims to make an in-depth investigation on different linear and nonlinear optical and structural characteristics of different phases of TiO2. Correspondingly, extensive challenges to synthesise different high quality TiO2 nanostructure derivatives such as nanotubes, nanospheres, nanoflowers etc. are continuing. Here, different nanostructures of anatase TiO2 were synthesised and analysed. Morphologically different nanostructures were found to have different impact on their physical and electronic properties such as varied surface area, dissimilar quantum confinement and hence diverged suitability for different applications. In view of the advantages of TiO2, it can act as an excellent matrix for nanoparticle composite films. These composite films may lead to several advantageous functional optical characteristics. Detailed investigations of these kinds of nanocomposites were also performed, only to find that these nanocomposites showed higher adeptness than their parent material. Fine tuning of these parameters helps researchers to achieve high proficiency in their respective applications. These innumerable opportunities aims to encompass the new progress in studies related to TiO2 for an efficient utilization in photo-catalytic or photo-voltaic applications under visible light, accentuate the future trends of TiO2-research in the environment as well as energy related fields serving promising applications benefitting the mankind. The last section of the thesis discusses the applicability of analysed nanomaterials for dye sensitised solar cells followed by future suggestions.
Sumangala,R; Saseendran Pillai, P R(Cochin University OF Science and Technology, December , 1996)
[+]
[-]
Abstract:
The main objective of carrying out this investigation is to develop suitable transducer array systems so that underwater pipeline inspection could be carried out in a much better way, a focused beam and electronic steering can reduce inspection time as well. Better results are obtained by optimizing the array parameters. The spacing between the elements is assumed to be half the wavelength so that the interelement interaction is minimum. For NDT applications these arrays are operated at MHz range. The wavelengths become very small in these frequency ranges. Then the size of the array elements becomes very small, requiring hybrid construction techniques for their fabrication. Transducer elements have been fabricated using PVDF as the active, mild steel as the backing and conducting silver preparation as the bonding materials. The transducer is operated in the (3,3) mode. The construction of a high frequency array is comparatively complicated. The interelement spacing between the transducer elements becomes considerably small when high frequencies are considered. It becomes very difficult to construct the transducer manually. The electrode connections to the elements can produce significant loading effect. The array has to be fabricated using hybrid construction techniques. The active materials has to be deposited on a proper substrate and etching techniques are required to fabricate the array. The annular ring, annular cylindrical or other similar structural forms of arrays may also find applications in the near future in treatments were curved contours of the human body are affected.
Vijayan, K K; Dr.Abdul Rasheed, T M(Cochin University Of Science And Technology, October 8, 2003)
[+]
[-]
Abstract:
The central theme of this research concerns the study of vibrationally excited
molecules. We have used the local mode description of such vibrational states, and this
-model has now gained general acceptance. A central feature of the model is the
Wloealizafion of vibrational energy. A study of these high—energy localized states provides
example, becauseof this localization, overtone spectra, which measure the absorption of
T vibrational energy, are extremely sensitive to the properties of X-H bonds. We also use
-overtone spectra to study the conformation of molecules, i.e., the relative internal
orientation of their bonds. The thesis comprises six chapters
Description:
Department of Physics Cochin
University of Science and Technology
Lakshmanan, P T; Dr.Krishnan Nambisan, P N(Cochin University Of Science And Technology, January , 1982)
[+]
[-]
Abstract:
The subsequent chapters of the Thesis deal with the toxic
effects of mercury, copper, zinc und~1ead on these bivalve
molluecs, their accumulation and distribution among various
organs of the animals and also the motel retention winstica
by the three species. Static biousauy tests have been conducted
in these studies. It was found that the concentrations of
the various metals studied in these organism are well below
the permitted level given far ease ahellfienes (crab and ehrimgi
and that these maliuscs are very good integrators ef trace
metals from their environment and may be used as an indicator
organism sf metal pallutaute.
The present investigutionsemphaeie the need for a clean
coastal water and gives a serious warning regarding the possiblc
route of heavy metals in ta human body thraugh marine food
chain.
Description:
School Of Marine Sciences
Cochin University Of Science And Technology
Namboothiripad,P V S; Dr.Parameswaran, Nair N(Cochin University of Science and Technology, November 1, 1979)
[+]
[-]
Abstract:
The present study is intended to provide a new scientific approach to the solution of the worlds cost engineering problems encountered in the chemical industries in our nation. The problem is that of cost estimation of equipments especially of pressure vessels when setting up chemical industries .The present study attempts to develop a model for such cost estimation. This in turn is hoped would go a long way to solve this and related problems in forecasting the cost of setting up chemical plants.
Zeena, Hamza P; Dr.Thomas, Kurian(Cochin University of Science And Technology, October , 2012)
[+]
[-]
Abstract:
Biodegradation is the chemical degradation of materials brought
about by the action of naturally occurring microorganisms. Biodegradation
is a relatively rapid process under suitable conditions of moisture, temperature
and oxygen availability. The logic behind blending biopolymers such as starch
with inert polymers like polyethylene is that if the biopolymer component is
present in sufficient amount, and if it is removed by microorganisms in the
waste disposal environment, then the base inert plastic should slowly
degrade and disappear.
The present work focuses on the preparation of biodegradable and
photodegradable blends based on low density polyethylene incorporating small
quantities of ionomers as compatibilizers.
The thesis consists of eight chapters. The first chapter presents an
introduction to the present research work and literature survey. The details of
the materials used and the experimental procedures undertaken for the study
are described in the second chapter. Preparation and characterization of low
density polyethylene (LDPE)-biopolymer (starch/dextrin) blends are
described in the third chapter. The result of investigations on the effect of
polyethylene-co-methacrylic acid ionomers on the compatibility of LDPE
and starch are reported in chapter 4. Chapter 5 has been divided into two
parts. The first part deals with the effect of metal oxides on the
photodegradation of LDPE. The second part describes the function of
metal stearates on the photodegradation of LDPE. The results of the
investigations on the role of various metal oxides as pro-oxidants on the
degradation of ionomer compatibilized LDPE-starch blends are reported in
chapter 6. Chapter 7 deals with the results of investigations on the role of
various metal stearates as pro-oxidants on the degradation of ionomer
compatibilized LDPE-starch blends. The conclusion of the investigations is
presented in the last chapter of the thesis.
Description:
Department of Polymer Science and Rubber Technology,
Cochin University of Science and Technology
The present study is an attempt to find out the ralation between RNA/DNA ratio, protein,percentage growth rate and specific growth rate of prawn,Penaeus indicus with respect to Nervous system, Eyestalk and Muscle tissues during ontogenesis. We have isolated and purified a natural agglutinin in the hemolymph of P.indicus with antigenecity, agglutinating, hemolytic and antibacterial properties. The influence of growth and environmental parameters on the level of agglutinin in the hemolymph was studied. Agglutinin concentration during normal growth process was compared. The agglutinin concentration in the hemolymph was quantified through developing ELISA, which is useful in health monitoring studies of individual species. Complete amino acid composition of both the subunits of P.indicus agglutinin were analysed. P.indicus agglutinin showed similarity to those proteins having antigenecity,hemolytic and agglutinating properties.Hence, agglutinin was considered as a natural defence protein in the hemolymph of P.indicus responsible for immune surveillance. The humoral defence mechanism of agglutinin was a co-operative effort with hemocytes and complement system. The composition of isolated agglutinin of P.indicus amino acids will be helpful in the synthesis of new antibacterial analogues which can be used against disease causing organisms.
Description:
Dept. of Biotechnology, Cochin University of Science and Technology
Manjusha,K P; Dr.Saleena, Mathew(Cochin University of Science and Technology, April , 2011)
[+]
[-]
Abstract:
The present study is aimed at the isolation and characterization of glycosaminoglycans from selected tissues of two commercially important species of cephalopods;squid,Loligo duvauceli and cuttlefish,Sepia pharaonis,keeping in view of the aforementioned benefits on the utilization of waste generated during processing.The cephalopod GAGs may also be expected to have an effect on various physiological functions based on the results obtained from GAGs from other sources.In addition,knowledge of the chemical structure of macromolecules that constitute major components of extracellular matrix(ECM) will be helpful in understanding their interactions with other matrix components.
Description:
School of Industrial Fisheries,
Cochin University of Science and Technology
Bijina, B; Dr.Chandrasekaran,M(Cochin University of Science & Technology, May , 2006)
[+]
[-]
Abstract:
Protease inhibitors are one of the most important tools of nature for
regulating the proteolytic activity of their target proteases. They are
synthesized in biological systems and they play a critical role in controlling
a number of diverse physiological functions. The current investigation
focused on the isolation, purification and characterization of a novel
protease inhibitor from Moringa oleifera. The results obtained during the
course of study opens new perspectives for the utilization of protease
inhibitor from Moringa oleifera for various pharmaceutical, agricultural and
food industries. The biological and physicochemical properties exhibited by
the novel protease inhibitor from Moringa oleifera clearly testify its
suitability for the development as a drug for application in pharmaceutical
industries such as anticoagulant agent or biocontrol agent in agriculture and
even as a food preservant. There is a scope for further research on the
structure elucidation and protein engineering towards a wide range of
further applications. Detailed structure/function analysis of these proteins is
important to facilitate their use in genetic engineering for various
applications.
Description:
Department of Biotechnology,
Cocbin University of Science and Technology
Sapna, K; Dr.Elyas, K K(Cochin University of Science And Technology, March , 2013)
[+]
[-]
Abstract:
The microorganisms are recognized as important sources of protease
inhibitors which are valuable in the fields of medicine, agriculture and
biotechnology. The protease inhibitors of microbial origin are found to be versatile
in their structure and mode of inhibition that vary from those of other sources.
Although surplus of low molecular weight non-protein protease inhibitors from
microorganisms have been reported, there is a dearth of reports on proteinaceous
protease inhibitors. The search for new metabolites from marine organisms has
resulted in the isolation of more or less 10,000 metabolites (Fuesetani and
Fuesetani, 2000) many of which are gifted with pharmacodynamic properties. The
existence of marine microorganisms was reported earlier, and they were found to
be metabolically and physiologically dissimilar from terrestrial microorganisms.
Marine microorganisms have potential as important new sources of enzyme
inhibitors and consequently a detailed study of new marine microbial inhibitors
will provide the basis for future research (Imada, 2004).
Description:
Department of Biotechnology, Cochin University of Science and Technology
Joshy, M K; Dr.Rani,Joseph(Cochin University of Science and Technology, October , 2007)
[+]
[-]
Abstract:
The aim of this
investigation is to study the effectiveness of isora fibre as reinforcement material
in short and long forms, for unsaturated polyester and epoxy resins.Studies on the optimization of fibre length and fibre loading of
randomly oriented isora-polyester composite are described.The
salient features of the alkali treatment of short isora fibre on the properties of
randomly oriented isora-polyester composite are outlined in this thesis.The
effect of surface modification of the hydrophilic isora fibre by different chemical
treatments on the properties of randomly oriented isora-polyester composite is
outlined.The properties of oriented and
randomly oriented isora fibre reinforced epoxy composites with special reference
to the effect of fibre loading are reported and also the dynamic mechanical
properties ofthe oriented and randomly oriented isora-polyester and isora-epoxy
composites are presented and the water absorption kinetics
of oriented and randomly oriented isora-polyester composites and oriented isoraepoxy
composites are given. The effect of hot air oven aging on the tensile and
flexural properties of oriented isora-polyester and isora-epoxy composites are
also reported in this thesis.
Description:
Department of Polymer Science and Rubber Technology,Cochin University of
Science and Technology