Vinu, Thomas; Dr.Mathew, K T(Cochin University of Science & Technology, September , 2008)
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Abstract:
Electromagnetic tomography has been applied to problems in
nondestructive evolution, ground-penetrating radar, synthetic aperture
radar, target identification, electrical well logging, medical imaging
etc. The problem of electromagnetic tomography involves the
estimation of cross sectional distribution dielectric permittivity,
conductivity etc based on measurement of the scattered fields. The
inverse scattering problem of electromagnetic imaging is highly non
linear and ill posed, and is liable to get trapped in local minima. The
iterative solution techniques employed for computing the inverse
scattering problem of electromagnetic imaging are highly computation
intensive. Thus the solution to electromagnetic imaging problem is
beset with convergence and computational issues. The attempt of this
thesis is to develop methods suitable for improving the convergence
and reduce the total computations for tomographic imaging of two
dimensional dielectric cylinders illuminated by TM polarized waves,
where the scattering problem is defmed using scalar equations. A multi
resolution frequency hopping approach was proposed as opposed to
the conventional frequency hopping approach employed to image large
inhomogeneous scatterers. The strategy was tested on both synthetic
and experimental data and gave results that were better localized and
also accelerated the iterative procedure employed for the imaging. A
Degree of Symmetry formulation was introduced to locate the scatterer
in the investigation domain when the scatterer cross section was
circular. The investigation domain could thus be reduced which
reduced the degrees of freedom of the inverse scattering process. Thus
the entire measured scattered data was available for the optimization of
fewer numbers of pixels. This resulted in better and more robust reconstructions of the scatterer cross sectional profile. The Degree of
Symmetry formulation could also be applied to the practical problem
of limited angle tomography, as in the case of a buried pipeline, where
the ill posedness is much larger. The formulation was also tested
using experimental data generated from an experimental setup that was
designed. The experimental results confirmed the practical
applicability of the formulation.
Description:
Department of Electronics,
Cochin University of Science and Technology
Sathiyamoorthy,V; Dr.Mohan Kumar, K(Department of Atmospheric Sciences, 2001)
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Abstract:
The aim of the present study is to understand the biennial scale stratosphere-troposphere interactions over India, and synoptic to interannual timescale meridional stratosphere-troposhere exchanges caused by upper tropospheric/lower stratospheric longwaves using NCEP/NCAR reanalysis data and satellite measured total ozone data. The biennial timescale interaction between lower stratosphere and troposphere over Thumba is analysed using high-resolution radiosonde data. The results suggest that TBO and QBO are two different phenomena with nearly biennial periodicity. Interannual timescale meridional stratosphere-troposphere exchanges caused by the newly documented Asia Pacific Wave (APW) were analysed using ozone as tracer of atmospheric motion. Synoptic timescale meridional stratosphere-troposhere exchanges caused by subtropical upper tropospheric long waves over Asia were studied using global total ozone measurements from TOMS. This research work can be extended to study the influence of decadal scale epochal nature in Indian summer monsoon activity on the APW generated total ozone anomalies around the globe and the trend estimates in total ozone
Manoj, G Tharian; Dr C.G Nandakumar(Cochin University of Science and Technology, March 16, 2015)
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Abstract:
Hat Stiffened Plates are used in composite ships and are gaining popularity in metallic ship
construction due to its high strength-to-weight ratio. Light weight structures will result in greater
payload, higher speeds, reduced fuel consumption and environmental emissions. Numerical
Investigations have been carried out using the commercial Finite Element software ANSYS 12 to
substantiate the high strength-to-weight ratio of Hat Stiffened Plates over other open section
stiffeners which are commonly used in ship building.
Analysis of stiffened plate has always been a matter of concern for the structural engineers
since it has been rather difficult to quantify the actual load sharing between stiffeners and
plating. Finite Element Method has been accepted as an efficient tool for the analysis of stiffened
plated structure. Best results using the Finite Element Method for the analysis of thin plated
structures are obtained when both the stiffeners and the plate are modeled using thin plate
elements having six degrees of freedom per node. However, one serious problem encountered
with this design and analysis process is that the generation of the finite element models for a
complex configuration is time consuming and laborious. In order to overcome these difficulties
two different methods viz., Orthotropic Plate Model and Superelement for Hat Stiffened Plate
have been suggested in the present work.
In the Orthotropic Plate Model geometric orthotropy is converted to material orthotropy
i.e., the stiffeners are smeared and they vanish from the field of analysis and the structure can be
analysed using any commercial Finite Element software which has orthotropic elements in its
element library. The Orthotropic Plate Model developed has predicted deflection, stress and
linear buckling load with sufficiently good accuracy in the case of all four edges simply
supported boundary condition. Whereas, in the case of two edges fixed and other two edges
simply supported boundary condition even though the stress has been predicted with good
accuracy there has been large variation in the deflection predicted. This variation in the
deflection predicted is because, for the Orthotropic Plate Model the rigidity is uniform throughout the plate whereas in the actual Hat Stiffened Plate the rigidity along the line of
attachment of the stiffeners to the plate is large as compared to the unsupported portion of the
plate.
The Superelement technique is a method of treating a portion of the structure as if it were a
single element even though it is made up of many individual elements. The Superelement has
predicted the deflection and in-plane stress of Hat Stiffened Plate with sufficiently good accuracy
for different boundary conditions. Formulation of Superelement for composite Hat Stiffened
Plate has also been presented in the thesis. The capability of Orthotropic Plate Model and
Superelement to handle typical boundary conditions and characteristic loads in a ship structure
has been demonstrated through numerical investigations.
Sarada,S; Sankaranarayanan,K C(School of Management studies, Faculty of Social sciences, 2004)
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Abstract:
The focus of this study is the stress of women entrepreneurs.As stress is associated with constraints and demands, and as a set of emerging conditions seem to affect the quality of life of women, it is more than just an occasional need to enquire in to the possibilities of promoting entrepreneurship by empowering women.As women entrepreneurs are increasingly involved in inherently complicated activities of improving their enterprise functioning ,it would be appropriate for women entrepreneurs to focus on transformational coping interventions.The study is limited to women entrepreneurs in the tiny sector.Women entrepreneurs registered in the Distric Industries ( DIC) and in the Kerala State Women’s Industries Association (KSWIA) are only selected for the study.It gaves a detailed description about empowerment of women.The social , economic ,political,ecological,and psychological importance of the study are detailed.It explains the family related stress, and the contextual system.This study is suggested on beliefs and values of women about their self-perception influencing gender bias, which contribute to stress and coping.This study is also needed about women’s believes and expectations about the probable effectiveness of various course of action and their ability to perform those actions.It is also neede for appraising coping potential of women and enhancing their stress base.It is important to research on stress and self-concept
Anupama Nair, P R; Dr.Mohammed Salih,K Y; Dr.Sujatha, C H(Cochin University Of Science And Technology, May , 2008)
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Abstract:
Poisoning by pesticides from agricultural fields is a serious water
pollution problem and its environmental long-term effect may result in the
incidence of poisoning of fish and other aquatic life forms (jyothi and
Narayan, 1999). Fishes like Heteropneustesfbssilis and C/arius batrac/nus are
especially prone to serious pesticide pollution as their habitat is mostly the
agriculture area. Though only few studies are conducted in this area, it can
be assessed from the local information that, population of such fish is on
the verge of vulnerability due to extensive use of pesticides. The knowledge
of sublethal effects of xenobiotic compounds on hematological parameters,
enzyme activities and metabolite concentrations is very important to
delineate the fish health status and provide a future understanding of
ecological impacts. These pesticides act by causing inhibition of
cholinesterase enzymes (ChE) by formation of enzyme inhibitor complex
(O'Brien, 1976) and damaging the nervous system. These effects may result
in metabolic disorders. Associated to cholinesterase activities, a study of
other enzymes such as phosphatases and aminotransferases close to
intermediary metabolite determination provides a wider view of
metabolism. Interest in toxicological aspects has grown in recent years and
research is now increasingly focused on mechanistic aspects of oxidative damage and cellular responses in biological system. The term ‘biomarker’ is
generally used in a broad sense to include almost any measurement
reflecting an interaction between a biological system and a potential hazard,
which may be chemical, physical or biological (WHO, 1993). As biomarker
stands for immediate responses, they are used as early warning signals of
biological effects caused by environmental pollutants.
The present work attempts to assess the toxicity of organophosphorus
insecticide monocrotophos on the experimental organism selected for this
study namely stinging catfish (Heteropneustesfossi/is) (Bloch), and to probe
into the stress responses of the organism
Description:
Department of Marine Biology, Microbiology and
Biochemistry, Cochin University of Science and Technology
Varughese,Philip; Prathapachandra Kurup, M R(Dept. of Applied Chemistry, July , 2004)
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Abstract:
The study deals with structural and spectral investigations of transition metal complexes of di-2-pyridyl ketone N(4),N(4)-disubstituted thiosemicarbazones. The main objective and scope of the work deals with di-2-pyridyl ketone N(4),N(4)-disubstituted thiosemicarbazones are quardridentate NNNS donor ligands. To chosen this ligand for study because, the ligands are prepared and characterized for the first time, since there are two pyridyl nitorgens, dimmers and polymers of complexes may result leading to interesting structural aspects. The work includes the preparation of the thiosemicarbzones and their structural and spectral studies, synthesis and spectral characterization of complexes of copper(II),,nickel(II),manganese(II), dioxovanadium(V),cobalt(III),zinc(II),cadmium(II) of the ligand HL, synthesis and spectral characterization of complexes of copper(II),manganese(II), of the ligand HL and the development of X-ray quality crystals and its X-ray diffraction studies. The structural characterization techniques are elemental analysis, conductivity measurements, magnetic measurements, electronic spectroscopy, H NMR spectroscopy, Infrared spectroscopy and X-ray crystallography.
Bessy Raj, B N; Dr.Prathapachandra Kurup,M R(Cochin University of Science and Technology, February , 2009)
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Abstract:
The present work deals with the complexation of Schiff
bases of aroylhydrazines with various transition metal ions. The hydrazone
systems selected for study have long 7I:-delocalized chain in the ligand molecule
itself, which get intensified due to metal-to-ligand or ligand-to-metal charge
transfer excitations upon coordination. Complexation with metal ions like copper,
nickel, cobalt, manganese, iron, zinc and cadmium are tried. Various spectral
techniques are employed for characterization. The structures of some complexes
have been well established by single crystal X-ray diffraction studies. The nonIinaer
optical studies of the ligands and complexes synthesized have been studied
by hyper-Rayleigh scattering technique.The work is presented in seven chapters and the last one deals with
summary and conclusion. One of the hydrazone system selected for study proved
that it could give rise to polymeric metal complexes. Some of the copper, nickel,
zinc and cadmium complexes showed non-linear optical activity. The NLO
studies of manganese and iron showed negative result, may be due to the inversion
centre of symmetry within the molecular lattice.
Description:
Department of Applied Chemistry,
Cochin University of Science and Technology
Rajive, Tomy M; Dr.Jayalekshmi, S(Cochin University Of Science And Technology, July 20, 2012)
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Abstract:
The main challenges in the deposition of cathode materials in thin film form are
the reproduction of stoichiometry close to the bulk material and attaining higher
rates of deposition and excellent crystallinity at comparatively lower annealing
temperatures. There are several methods available to develop stoichiometric thin
film cathode materials including pulsed laser deposition; plasma enhanced
chemical vapor deposition, electron beam evaporation, electrostatic spray
deposition and RF magnetron sputtering. Among them the most versatile
method is the sputtering technique, owing to its suitability for micro-fabricating
the thin film batteries directly on chips in any shape or size, and on flexible
substrates, with good capacity and cycle life. The main drawback of the
conventional sputtering technique using RF frequency of 13.56MHz is its lower
rate of deposition, compared to other deposition techniques A typical cathode
layer for a thin film battery requires a thickness around one micron. To deposit
such thick layers using convention RF sputtering, longer time of deposition is
required, since the deposition rate is very low, which is typically 10-20 Å/min.
This makes the conventional RF sputtering technique a less viable option for
mass production in an economical way.
There exists a host of theoretical and experimental evidences and results that
higher excitation frequency can be efficiently used to deposit good quality films
at higher deposition rates with glow discharge plasma. The effect of frequencies
higher than the conventional one (13.56MHz) on the RF magnetron sputtering
process has not been subjected to detailed investigations. Attempts have been
made in the present work, to sputter deposit spinel oxide cathode films, using
high frequency RF excitation source. Most importantly, the major challenge faced by the thin film battery based on the LiMn2O4 cathode material is the poor capacity retention during charge discharge cycling. The major causes for the capacity fading reported in LiMn2O4cathode materials are due to, Jahn-Teller distortion, Mn2+ dissolution into the electrolyte and oxygen loss in cathode material during cycling. The work discussed in this thesis is an attempt on overcoming the above said challenges and developing a high capacity thin film cathode material.
Description:
Division for Research in Advanced Materials
Department of Physics
Cochin University of Science and Technology
Sivakumar,S; Prathapachandra Kurup, M R(Department of Applied Chemistry, 2002)
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Abstract:
The primary aim of these investigations was to probe the spectroscopic, electrochemical, biological and single crystal X-ray diffraction studies of some selected transition metal complexes of 4N-monosubstituted thiosemicarbazones. Transition metal complexes with thiosemicarbazones exhibit a wide range of stereochemistries and possess potential biological activity. Metal complexes of thiosemicarbazones are proved to have improved pharmacological and therapeutic effects. The studies are conducted to bring about a fair understanding of the structure activity relationship and to develop certain effective and economical metal-based antimicrobial agents. Study showed that the thiosemicarbazones have antibacterial, antiviral and antiproliferative properties and hence used against tuberculosis, leprosy, psoriasis, rheumatism, trypanosomiasis and coccidiosis. Certain thiosemicarbazones showed a selective inhibition of HSV and HIV infections. The insolubility of most thiosemicarbazones in water causes difficulty in the oral administration in clinical practice. Transition metal complexes are found to have more activity than uncombined thiosemicarbazones. They exhibit a variety of denticity and can be varied by proper substitution. The stereochemistry assumed by the thiosemicarbazones during the coordination with transition metal ions depends on the factors such as preparative conditions and availability of additional bonding site in the ligand moiety and charge of the ligand. The resulting complexes exhibited a wide range of stereochemistries and have biomimic activity and potential application as sensors
Sivakumar,S; Prathapachandra Kurup, M R(Department of Applied Chemistry, 2002)
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Abstract:
The primary aim of these investigations was to probe the spectroscopic, electrochemical, biological and single crystal X-ray diffraction studies of some selected transition metal complexes of 4N-monosubstituted thiosemicarbazones. Transition metal complexes with thiosemicarbazones exhibit a wide range of stereochemistries and possess potential biological activity. Metal complexes of thiosemicarbazones are proved to have improved pharmacological and therapeutic effects. The studies are conducted to bring about a fair understanding of the structure activity relationship and to develop certain effective and economical metal-based antimicrobial agents. Study showed that the thiosemicarbazones have antibacterial, antiviral and antiproliferative properties and hence used against tuberculosis, leprosy, psoriasis, rheumatism, trypanosomiasis and coccidiosis. Certain thiosemicarbazones showed a selective inhibition of HSV and HIV infections. The insolubility of most thiosemicarbazones in water causes difficulty in the oral administration in clinical practice. Transition metal complexes are found to have more activity than uncombined thiosemicarbazones. They exhibit a variety of denticity and can be varied by proper substitution. The stereochemistry assumed by the thiosemicarbazones during the coordination with transition metal ions depends on the factors such as preparative conditions and availability of additional bonding site in the ligand moiety and charge of the ligand. The resulting complexes exhibited a wide range of stereochemistries and have biomimic activity and potential application as sensors.