Investigations on the biology of Indian Mackerel Rastrelliger kanagurta (Cuvier) along the Central Kerala coast with special reference to maturation, feeding and lipid dynamics

Dept. of Marine Biology, Microbiology & Biochemistry, Cochin University of Science and Technology

Investigations on broadband planar monopole and slot radiators and their suitability for UWB applications

In recent years, there is a visible trend for products/services which demand seamless integration of cellular networks, WLANs and WPANs. This is a strong indication for the inclusion of high speed short range wireless technology in future applications. In this context UWB radio has a significant role to play as an extension/complement to existing cellular/access technology. In the present work, we have investigated two major types of wide band planar antennas: Monopole and Slot. Four novel compact broadband antennas, suitable for poratble applications, are designed and characterized, namely 1. Elliptical monopole 2. Inverted cone monopole 3. Koch fractal slot 4. Wide band slot The performance of these designs have been studied using standard simulation tools used in industry/academia and they have been experimentally verified. Antenna design guidelines are also deduced by accounting the resonances in each structure. In addition to having compact sized, high efficiency and broad bandwidth antennas, one of the major criterion in the design of impulse-UWB systems have been the transmission of narrow band pulses with minimum distortion. The key challenge is not only to design a broad band antenna with constant and stable gain but to maintain a flat group delay or linear phase response in the frequency domain or excellent transient response in time domain. One of the major contributions of the thesis lies in the analysis of the frequency and time-domain response of the designed UWB antennas to confirm their suitability for portable pulsed-UWB systems. Techniques to avoid narrowband interference by engraving narrow slot resonators on the antenna is also proposed and their effect on a nano-second pulse have been investigated.

Investigations on Eco-friendly Natural Insecticides

Instead of developing easily degradable, and low-priced insecticides, we are going after highly sophisticated chemicals. Here, an attempt is being made to develop safer formulations of insecticides of botanical origin. Different parts of the plants were chosen based on their use in countryside and villages The dried plant materials were extracted with petroleum ether, and were applied on Tribolium castaneum. The results were statistically analysed. The active principles from Croton tigilium and Leea sambucina, the most potential plants, were isolated using Column Chromatography, TLC, and Hydrolysis. The isolated principles were analysed spectroscopically ( UV-Vis., IR, NMR, and MS ) to identify their chemical nature. The active principles from Leea and Croton were identified as a cholisterate derivative and a phorbol derivative respectively. In order to ascertain the environmental combatibility of the principles, degradation by soil bacteria was studied. The isolated principles were made into three type of formulations using stabilizers .The formulations were applied on Snake gourd semilooper, Pulse beetle, and mosquito larvae. Also the biocidal activity of the formulations was studied. Both Leea derivative and Croton derivative could be formulated effectively and were effective against a variety of pests. They are eco-friendly, as there is no artificial chemicals involved.

Multichannel Remote Data Acquisition and Analysing Systems For Fisheries / Environmental Investigations

Remote Data acquisition and analysing systems developed for fisheries and related environmental studies have been reported. It consists of three units. The first one namely multichannel remote data acquisition system is installed at the remote place powered by a rechargeable battery. It acquires and stores the 16 channel environmental data on a battery backed up RAM. The second unit called the Field data analyser is used for insitue display and analysis of the data stored in the backed up RAM. The third unit namely Laboratory data analyser is an IBM compatible PC based unit for detailed analysis and interpretation of the data after bringing the RAM unit to the laboratory. The data collected using the system has been analysed and presented in the form of a graph. The system timer operated at negligibly low current, switches on the power to the entire remote operated system at prefixed time interval of 2 hours.Data storage at remote site on low power battery backedupRAM and retrieval and analysis of data using PC are the special i ty of the system. The remote operated system takes about 7 seconds including the 5 second stabilization time to acquire and store data and is very ideal for remote operation on rechargeable bat tery. The system can store 16 channel data scanned at 2 hour interval for 10 days on 2K backed up RAM with memory expansion facility for 8K RAM.

Investigations on ecofriendly de-inking agents for paper recycling

School of Environmental Studies, Cochin University of Science and Technology

Analytical Investigations 0n Collapse of Cylindrical Submarine Shells

Submarine hull structure is a watertight envelope, under hydrostatic pressure when in operation. Stiffened cylindrical shells constitute the major portion of these submarine hulls and these thin shells under compression are susceptible to buckling failure. Normally loss of stability occurs at the limit point rather than at the bifurcation point and the stability analysis has to consider the change in geometry at each load step. Hence geometric nonlinear analysis of the shell forms becomes. a necessity. External hydrostatic pressure will follow the deformed configuration of the shell and hence follower force effect has to be accounted for. Computer codes have been developed based on all-cubic axisymmetric cylindrical shell finite element and discrete ring stiffener element for linear elastic, linear buckling and geometric nonIinear analysis of stiffened cylindrical shells. These analysis programs have the capability to treat hydrostatic pressure as a radial load and as a follower force. Analytical investigations are carried out on two attack submarine cylindrical hull models besides standard benchmark problems. In each case, the analysis has been carried out for interstiffener, interdeepframe and interbulkhead configurations. The shell stiffener attachment in each of this configuration has been represented by the simply supported-simply supported, clamped-clamped and fixed-fixed boundary conditions in this study. The results of the analytical investigations have been discussed and the observations and conclusions are described. Rotation restraint at the ends is influential for interstiffener and interbulkhead configurations and the significance of axial restraint becomes predominant in the interbulkhead configuration. The follower force effect of hydrostatic pressure is not significant in interstiffener and interdeepframe configurations where as it has very high detrimental effect on buckling pressure on interbulkhead configuration. The geometric nonlinear interbulkhead analysis incorporating follower force effect gives the critical value of buckling pressure and this analysis is recommended for the determination of collapse pressure of stiffened cylindrical submarine shells.

Synthesis and Characterization of Some Organic Semiconductors and Investigations on the Effect of Swift Heavy Ions on Their Properties

In this work polymers belonging to polyaniline and polyaniline doped with camphor sulphonic acid are synthesised. Cobalt phthalocyanine is an interesting candidate belonging to the tetramers. Studies on the composites containing cobalt phthalocyanine tetramer and polyaniline doped with camphor sulphonic acid for various concentration are also undertaken in order to understand the mechanism. RF plasma polymerised aniline and furfural are prepared. The structural and electrical properties are evaluated. The bombardment of swift heavy ions of these films are carried out and the effect of irradiation on their properties is also investigated.

Structural and biological investigations of metal complexes of some substituted thiosemicarbazones

Department of Applied Chemistry, Cochin University of Science and Technology

Investigations on some Y-Zeolite encapsulated transition metal complexes of Schiff bases

Department of Applied Chemistry, Cochin University of Science and Technology

Laser Induced Photothermal Investigations on Thermal and Transport Properties of Certain Selected Photonic Materials

Discovery of coherent optical sources four decades ago has revolutionized all fields of scientific development. One of the path breaking applications of lasers is the emergence of various thermo optic techniques to unravel some of the mysteries of light matter interactions.Thermo optic technique is a valuable tool to evaluate optical and thermal properties of materials in solid,liquid and gaseous states .This technique can also be employed effectively in nondestructive quality evaluation. In this doctoral thesis , the use of photothermal techniques based on photoacoustic and photothermal deflection phenomena for the study of certain class of photonics materials such as semiconductors, nano metal dispersed ceramics, composites of conducting polymers and liquid crystals is elaborated.

Investigations on some selected conducting polymers and polymer composites for possible optoelectronic applications

Department of Physics, Cochin University of Science and Technology

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

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.

Investigations on Low Frequency Piezofilm Hydrophones with Improved Performance

Department of Electronics, Cochin University of Science & Technology

Investigations on Nonlinear and Radiative Properties of Certain Photonic Materials

International School of Photonics, Cochin University of Science & Technology