Synthesis, characterization and physiochemical information, along with antimicrobial studies of some metal complexes derived from an ON donor semicarbazone ligand

Eight new transition metal complexes of benzaldehyde-N(4)–phenylsemicarbazone have been synthesized and characterized by elemental analyses, molar conductance, electronic and infrared spectral studies. In all the complexes, the semicarbazone is coordinated as neutral bidentate ligand. 1H NMR spectrum of [Zn(HL)2(OAc)2] shows that there is no enolisation of the ligand in the complex. The magnetic susceptibility measurements indicate that Cr(III), Mn(II), Fe(III), Co(II) and Cu(II) complexes are paramagnetic and Ni(II) is diamagnetic. The EPR spectrum of [Mn(HL)2(OAc)2] in DMF solution at 77K shows hyperfine sextet with low intensity forbidden lines lying between each of the two main hyperfine lines. The g values calculated for the [Cu(HL)2SO4] complex in frozen DMF, indicate the presence of unpaired electron in the dx2−y2 orbital. The metal ligand bonding parameters evaluated showed strong in-plane bonding and in-plane bonding. The ligand and complexes were screened for their possible antimicrobial activities.

Studies on the Synthesis and Transformations of A Few Dibenzoylalkene – Type Systems

The aim of the study is to synthesise several dibenzoylakene-type systems such as acenaphthenone-2-ylidene ketones 47 and phenanthrenone-9-ylidene ketones 48 by the condensation reaction of acenaphthenequinone and phenanthrenequinone with methyl ketones. Here studies the thermal and photochemical transformations of acenaphthaenone-2-ylidene ketones 3a-c.These acenaphthenone –2-ylidene ketones underwent extensive decomposition on heating. The objectives of present study is to synthesise acenaphthenone-2-ylidene ketones by the Claisen-Schmidt condensation of acenaphthenequinone and methyl ketones, it is to synthesise phenanthrenone –9-ylidene ketones by the Claisen-Schmidt condensation of phenanthrequinone and methyl ketones, thermal studies on acenaphthenone-2-ylidene ketones and phenanthrenone-9-ylidene ketones, photochemical studies on acenaphthenone-2-ylidene ketones and phenanthrenone –9-ylidene ketones to establish the generality of dibenzoyalkene rearrangement. Cyclic voltammetric studies on these dibezoyalkenes to compare their redox behaviour with that of the cis and trans isomers of dibenzoyl-ethylene, dibenzoylstilbene. These results should provide some information about their reactivity, and to assess and exploit the potential of these systems as quinonemethides. This study conclude that a number of new dibenzolalkene-type systems have been synthesized by the Claisen-Schmidt condensation of 1,2-diketones such as phenanthequinone and acenaphthenequinone with methyl ketones. Some of these compounds have been shown to undergo interesting photochemical transformations. Based on the results it is conclude that phenanthjrenone-9-ylidene ketones are excellent Michael acceptors. Methanol adds to these to yield the corresponding furanols. These furanols are unstable and are slowly converted to phenanthro-2 (3H)-furanones.

Studies on Rubber Composition as Passive Acoustic Materials in Underwater Electro Acoustic Tranducer Technology and Their aging Characteristic

The research work has been in the area of compounding and characterization of rubbers for use in under water electro acoustic transducers. The study also covers specific material system such as encapsulation materials, baffle material, seal material, etc. Life prediction techniques of under water rubbers in general have been established with reference to more than one functional property. Ranges of passive materials, besides the active sensing material go into the construction of underwater electro acoustic transducers. Reliability of the transducer is critically dependent on these passive materials. Rubbers are a major class of passive materials. The present work concentrates on these materials. Conventional rubbers are inadequate to meet many of the stringent function specific requirements. There exists a large gap of information in the rubber technology of underwater rubbers, particularly relating to underwater electro acoustic transducers. This study is towards filling up the gaps of information in this crucial area. Water intake into rubber is considered as the single most important issue for the long-term performance of rubbers, especially Neoprene. In this study, the cause and effects of a range of parameters affecting the water absorption by diffusion and permeation have been investigated.

STUDIES ON THE STRESS FLUCTUATIONS IN SHEARED STOKESIAN SUSPENSIONS USING CHAOS THEORY AND NONLINEAR DYNAMICS

The thesis report results obtained from a detailed analysis of the fluctuations of the rheological parameters viz. shear and normal stresses, simulated by means of the Stokesian Dynamics method, of a macroscopically homogeneous sheared suspension of neutrally buoyant non-Brownian suspension of identical spheres in the Couette gap between two parallel walls in the limit of vanishingly small Reynolds numbers using the tools of non-linear dynamics and chaos theory for a range of particle concentration and Couette gaps. The thesis used the tools of nonlinear dynamics and chaos theory viz. average mutual information, space-time separation plots, visual recurrence analysis, principal component analysis, false nearest-neighbor technique, correlation integrals, computation of Lyapunov exponents for a range of area fraction of particles and for different Couette gaps. The thesis observed that one stress component can be predicted using another stress component at the same area fraction. This implies a type of synchronization of one stress component with another stress component. This finding suggests us to further analysis of the synchronization of stress components with another stress component at the same or different area fraction of particles. The different model equations of stress components for different area fraction of particles hints at the possible existence a general formula for stress fluctuations with area fraction of particle as a parameter

Studies on Lactic Acid Bacteria from Tropical Fish and Shellfish

In this study, an attempt has been made to gather enough information regarding lactic acid bacteria from fish and shellfish of tropical regions. The occurrence and distribution of lactic acid bacteria in fresh and frozen marine fish and shellfish, farmed fish and shellfish, cured and pickled fish and shellfish have been investigated. Lactic Acid Bacteria (LAB) have for centuries been responsible for the fermentative preservation of many foods. They are used to retard spoilage and preserve foods through natural fermentations. They have found commercial applications as starter cultures in the dairy, baking, meat, fish, and vegetable and alcoholic beverage industries. They are industrially important organisms recognized for their fermentative ability as well as their nutritional benefits. These organisms produce various compounds such as organic acids, diacetyl, hydrogen peroxide and bacteriocins or bactericidal proteins during lactic fermentations.Biopreservation of foods using bacteriocin producing LAB cultures is becoming widely used. The antimicrobial effect of bacteriocins and other compounds produced during fermentation of carbohydrates are well known to inhibit the growth of certain food spoiling bacteria as well as a limited group of food poisoning and pathogenic bacteria LAB like Lactobacillus plantarum are widely used as starter cultures for the Production of fish ensilage. The present study is the first quantitative and qualitative study on the occurrence and distribution of lactic acid bacteria in fresh and frozen fish and prawn. It is concluded that Lactobacillus plantaruni was the predominant lactobacillus species in fresh and frozen fish and shellfish. The ability of selected Lactobacillus cultures to grow at low temperatures, high salt content, produce bacteriocins, rapidly ferment sugars and decrease the pH make them potential candidates for biopreservation of fish and shellfish.

Studies on Some Simple and Zeolite-Y Encapsulated 3d-Transition Metal Complexes of Schiff Bases Derived From 2-Aminobenzothiazole

In this regard Schiff base complexes have attracted wide attention. Furthermore, such complexes are found to play important role in analytical chemistry, organic synthesis, metallurgy, refining of metals, electroplating and photography. Many Schiff base complexes are reported in literature. Their properties depend on the nature of the metal ion as well as on the nature of the ligand. By altering the ligands it is possible to obtain desired electronic environment around the metal ion. Thus there is a continuing interest in the synthesis of simple and zeolite encapsulated Schiff base complexes of metal ions. Zeolites have a number of striking structural similarities to the protein portion of natural enzymes. Zeolite based catalysts are known for their remarkable ability of mimicking the chemistry of biological systems. In view of the importance of catalysts in all the areas of modern chemical industries, an effort has been made to synthesize some simple Schiff base complexes, heterogenize them by encapsulating within the supercages of zeoliteY cavities and to study their applications. The thesis deals with studies on the synthesis and characterization of some simple and zeoliteY encapsulated Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes and on the catalytic activity of these complexes on some oxidation reactions. Simple complexes were prepared from the Schiff base ligands SBT derived from 2-aminobenzothiazole and salicylaldehyde and the ligand VBT derived from 2-aminobenzothiazole and vanillin (4-hydroxy-3- methoxybenzaldehyde). ZeoliteY encapsulated Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes of Schiff base ligands SBT and VBT and also of 2-aminobenzothiazole were synthesized. All the prepared complexes were characterized using the physico-chemical techniques such as chemical analysis (employing AAS and CHN analyses), magnetic moment studies, conductance measurements and electronic and FTIR spectra. EPR spectra of the Cu(II) complexes were also carried out to know the probable structures and nature of Cu(II) complexes. Thermogravimetric analyses were carried out to obtain the information regarding the thermal stability of various complexes. The successful encapsulations of the complexes within the cavities of zeoliteY were ascertained by XRD, surface area and pore volume analysis. Assignments of geometries of simple and zeoliteY encapsulated complexes are given in all the cases. Both simple and zeoliteY encapsulated complexes were screened for catalytic activity towards oxidation reactions such as decomposition of hydrogen peroxide, oxidation of benzaldehyde, benzyl alcohol, 1-propanol, 2-propanol and cyclohexanol.

Studies on the Synthesis and Transformations of a Few Dibenzoylalkene-type Systems

The aim of the study is to synthesise several dibenzoylakene-type systems such as acenaphthenone-2-ylidene ketones 47 and phenanthrenone-9-ylidene ketones 48 by the condensation reaction of acenaphthenequinone and phenanthrenequinone with methyl ketones. Here studies the thermal and photochemical transformations of acenaphthaenone-2-ylidene ketones 3a-c.These acenaphthenone –2-ylidene ketones underwent extensive decomposition on heating. The objectives of present study is to synthesise acenaphthenone-2-ylidene ketones by the Claisen-Schmidt condensation of acenaphthenequinone and methyl ketones, it is to synthesise phenanthrenone –9-ylidene ketones by the Claisen-Schmidt condensation of phenanthrequinone and methyl ketones, thermal studies on acenaphthenone-2-ylidene ketones and phenanthrenone-9-ylidene ketones, photochemical studies on acenaphthenone-2-ylidene ketones and phenanthrenone –9-ylidene ketones to establish the generality of dibenzoyalkene rearrangement. Cyclic voltammetric studies on these dibezoyalkenes to compare their redox behaviour with that of the cis and trans isomers of dibenzoyl-ethylene, dibenzoylstilbene. These results should provide some information about their reactivity, and to assess and exploit the potential of these systems as quinonemethides. This study conclude that a number of new dibenzolalkene-type systems have been synthesized by the Claisen-Schmidt condensation of 1,2-diketones such as phenanthequinone and acenaphthenequinone with methyl ketones. Some of these compounds have been shown to undergo interesting photochemical transformations. Based on the results it is conclude that phenanthjrenone-9-ylidene ketones are excellent Michael acceptors. Methanol adds to these to yield the corresponding furanols. These furanols are unstable and are slowly converted to phenanthro-2 (3H)-furanones

STUDIES ON THE BIOLOGY OF THE WEDGE CLAM DONAX INCARNATUS (GMELIN) FROM THE MALIPPURAM BEACH OF KERALA

The present investigations have considerably enhanced the existing knowledge on the biology and distribution/availability pattern of D.incarnatus in the Malippuram region. The species occurs in good concentration during October - March/April, and disappears from the area during late premonsoon and monsoon months. Recolonising the area in September, it grows fast in the subsequent months. The life span of the species is estimated to be about an year. Studies on the reproductive biology of the species have revealed that there are two spawning peaks, the major peak in February - March and minor peak, in December. The salinity regime of the area influences the reproductive activity. These observations form the original contribution in the thesis. The information on variation in water content, protein,glycogen and lipid levels in relation to reproductive cycle has helped to a better understanding of the gametogenic activity and spawning of the species. Similarly, the findings on salinity tolerance and filtration rate have shown that small sized clams exhibit greater tolerance range than larger clams, and grow at a faster rate with active metabolism. It is hoped that these information would considerably add to the present knowledge of the basic facts which are relevant to the improvement and management of the clam fishery of this region.

Studies on the Deep - Water Crab Charybdis (Goniohellenus ) Smithii Macleay From the Seas Around India

The present study deals with a general introduction which outlines the objective of the study providing an exhaustive review of works on crabs with particular reference to deep-sea forms. In the first section, Taxonomy and Geographical disribution of the crab are dealt with. The species is described in detail based on several male and female specimens obtained from the pelagic and bottom collections, and its identity in Indian waters is established. It is also distinguished from a closely allied species so far not reported from Indian waters. The second section comprises the biology of the species and it is dealt with under four subheading, namely Habit and Habitats, Reproduction, Food and feeding and Proximate composition. The different habitats occupied by juveniles, subadults and adults of the species have been described and discussed in the light of available information on differential distribution of other related species. The reproductive biology is described in various details touching on gross anatomy and histology of the reproductive systems, spermatogenesis, oogenesis, size at maturity, ovarian maturation process, fecundity, egg carriage and breeding. The food and feeding habits of the species have been studied with reference to the different life stages such as juveniles, subadults and adults during the different phases of life based on stomach content analysis. The percentage of meat recovery and protein, carbohydrate and lipid content of meat have been described in the section dealing with proximate composition. In section three the distribution and abundance of the crab for the entire Indian EEZ and some contiguous ares have been described and illustrated in detail separately for pelagic and benthic realms. The size frequency disrtibution, sex ratios, length weight relationship and relative abundance of breeding population in the experimental catches have been dealt with in detail and discussed.

Some Studies and New Results on Multi Microprocessor Applications

One of the fastest expanding areas of computer exploitation is in embedded systems, whose prime function is not that of computing, but which nevertheless require information processing in order to carry out their prime function. Advances in hardware technology have made multi microprocessor systems a viable alternative to uniprocessor systems in many embedded application areas. This thesis reports the results of investigations carried out on multi microprocessors oriented towards embedded applications, with a view to enhancing throughput and reliability. An ideal controller for multiprocessor operation is developed which would smoothen sharing of routines and enable more powerful and efficient code I data interchange. Results of performance evaluation are appended.A typical application scenario is presented, which calls for classifying tasks based on characteristic features that were identified. The different classes are introduced along with a partitioned storage scheme. Theoretical analysis is also given. A review of schemes available for reducing disc access time is carried out and a new scheme presented. This is found to speed up data base transactions in embedded systems. The significance of software maintenance and adaptation in such applications is highlighted. A novel scheme of prov1d1ng a maintenance folio to system firmware is presented, alongwith experimental results. Processing reliability can be enhanced if facility exists to check if a particular instruction in a stream is appropriate. Likelihood of occurrence of a particular instruction would be more prudent if number of instructions in the set is less. A new organisation is derived to form the basement for further work. Some early results that would help steer the course of the work are presented.

Photoconductivity studies on some semiconducting thin films for photovoltaic applications

Photoconductivity (PC) processes may be the most suitable technique for obtaining information about the states in the gap. It finds applications in photovoItaics, photo detection and radiation measurements. The main task in the area of photovoltaics, is to increase the efficiency of the device and also to develop new materials with good optoelectronic properties useful for energy conversion, keeping the idea of cost effectiveness. Photoconduction includes generation and recombination of carriers and their transport to the electrodes. So thermal relaxation process, charge carrier statistics, effects of electrodes and several mechanisms of recombination are involved in photoconductivity.A major effect of trapping is to make the experimentally observed decay time of photocurrent, longer than carrier lifetime. If no trapping centers are present, then observed photocurrent will decay in the same way as the density of free carriers and the observed decay time will be equal to carrier lifetime. If the density of free carriers is much less than density of trapped carriers, the entire decay of photocurrent is effectively dominated by the rate of trap emptying rather than by the rate of recombination.In the present study, the decay time of carriers was measured using photoconductive decay (PCD) technique. For the measurements, the film was loaded in a liquid Helium cryostat and the temperature was controlled using Lakshore Auto tuning temperature controller (Model 321). White light was used to illuminate the required area of the sample. Heat radiation from the light source was avoided by passing the light beam through a water filter. The decay current. after switching off the illumination. was measured using a Kiethely 2000 multi meter. Sets of PCD measurements were taken varying sample temperature, sample preparation temperature, thickness of the film, partial pressure of Oxygen and concentration of a particular element in a compound. Decay times were calculated using the rate window technique, which is a decay sampling technique particularly suited to computerized analysis. For PCD curves with two well-defined regions, two windows were chosen, one at the fast decay region and the other at the slow decay region. The curves in a particular window were exponentially fitted using Microsoft Excel 2000 programme. These decay times were plotted against sample temperature and sample preparation temperature to study the effect of various defects in the film. These studies were done in order to optimize conditions of preparation technique so as to get good photosensitive samples. useful for photovoltaic applications.Materials selected for the study were CdS, In2Se3, CuIn2Se3 and CuInS2• Photoconductivity studies done on these samples are organised in six chapters including introduction and conclusion.

Impact of Information Communication Technology (ICT) on Professional Development and Educational Needs of Library Professionals in the Universities of Kerala

The shift from print to digital information has a high impact on all components of the academic library system in India especially the users, services and the staff. Though information is considered as an important resource, the use of ICT tools to collect and disseminate information has been in a slow pace in majority of the University libraries This may be due to various factors like insufficient funds, inadequate staff trained in handling computers and software packages, administrative concerns etc. In Kerala, automation has been initiated in almost all University libraries using library automation software and is under different stages of completion. There are not much studies conducted about the effects of information communication technologies on the professional activities of library professionals in the universities in Kerala. It is important to evaluate whether progress in ICT has had any impact on the library profession in these highest educational institutions. The aim of the study is to assess whether the developments in information communication technologies have any influence on the library professionals’ professional development, and the need for further education and training in the profession and evaluate their skills in handling developments in ICT. The total population of the study is 252 including the permanently employed professional library staff in central libraries and departmental libraries in the main campuses of the universities under study. This is almost a census study of the defined population of users. The questionnaire method was adopted for collection of data for this study, supplemented by interviews of Librarians to gather additional information. Library Professionals have a positive approach towards ICT applications and services in Libraries, but majority do not have the opportunities to develop their skills and competencies in their work environment. To develop competitive personnel in a technologically advanced world, high priority must be given to develop competence in ICT applications, library management and soft skills in library professionals, by the University administrators and Library associations. Library science schools and teaching departments across the country have to take significant steps to revise library science curriculum, and incorporate significant changes to achieve the demands and challenges of library science profession.

Studies,Design and Development of Network Security Enhancement Services Using Novel Cryptographic Algorithms

Internet today has become a vital part of day to day life, owing to the revolutionary changes it has brought about in various fields. Dependence on the Internet as an information highway and knowledge bank is exponentially increasing so that a going back is beyond imagination. Transfer of critical information is also being carried out through the Internet. This widespread use of the Internet coupled with the tremendous growth in e-commerce and m-commerce has created a vital need for infonnation security.Internet has also become an active field of crackers and intruders. The whole development in this area can become null and void if fool-proof security of the data is not ensured without a chance of being adulterated. It is, hence a challenge before the professional community to develop systems to ensure security of the data sent through the Internet.Stream ciphers, hash functions and message authentication codes play vital roles in providing security services like confidentiality, integrity and authentication of the data sent through the Internet. There are several ·such popular and dependable techniques, which have been in use widely, for quite a long time. This long term exposure makes them vulnerable to successful or near successful attempts for attacks. Hence it is the need of the hour to develop new algorithms with better security.Hence studies were conducted on various types of algorithms being used in this area. Focus was given to identify the properties imparting security at this stage. By making use of a perception derived from these studies, new algorithms were designed. Performances of these algorithms were then studied followed by necessary modifications to yield an improved system consisting of a new stream cipher algorithm MAJE4, a new hash code JERIM- 320 and a new message authentication code MACJER-320. Detailed analysis and comparison with the existing popular schemes were also carried out to establish the security levels.The Secure Socket Layer (SSL) I Transport Layer Security (TLS) protocol is one of the most widely used security protocols in Internet. The cryptographic algorithms RC4 and HMAC have been in use for achieving security services like confidentiality and authentication in the SSL I TLS. But recent attacks on RC4 and HMAC have raised questions about the reliability of these algorithms. Hence MAJE4 and MACJER-320 have been proposed as substitutes for them. Detailed studies on the performance of these new algorithms were carried out; it has been observed that they are dependable alternatives.

Studies on the Effects of Bottom Trawling on the Benthic Fauna off Veraval Coast, Gujarat

Bottom trawling is one among the most destructive human induced physical disturbances inflicted to seabed and its living communities. The bottom trawls are designed to tow along the sea floor, which on its operation indiscriminately smashes everything on their way crushing, killing, burying and exposing to predators the benthic fauna. Bottom trawling causes physical and biological damages that are irreversible, extensive and long lasting. The commercial trawling fleet of India consists of 29,241 small and medium-fishing boats. The northwest coast of India has the largest fishing fleet consisting of 23,618 mechanized vessels, especially the bottom trawlers. However, attempts were not made to study the impact of bottom trawling along Northwest coast of India. The estimated optimum fleet size of Gujarat is 1,473 mechanised trawlers while 7402 commercial trawlers are operated from the coast of Gujarat. Veraval port was designed initially for 1,200 fishing trawlers but 2793 trawlers are being operated from this port making it the largest trawler port of Gujarat. The aim of this study was to investigate the effects of bottom trawling on the substratum and the associated benthic communities of commercial trawling grounds of Veraval coast. The study compared the differences between the samples collected before and after experimental trawling to detect the impacts of bottom trawling. Attempts were made to assess the possible impact of bottom trawling on:(i) the sediment characteristics (ii)the sediment heavy metals (iii) epifauna (iv) macrobenthos and (v) meiobenthos. This study is expected to generate information on trawling impacts of the studied area that will help in better management of the biological diversity and integrity of the benthic fauna off Veraval coast. An exhaustive review on the studies conducted around the world and in India on impact of bottom trawling on the benthic fauna is also detailed.In the present study, the bottom trawling induced variations on sediment organic matter, epifauna, macrobenthos and meiobenthos were evident. It was also observed that the seasonal/ natural variations were more prominent masking the trawling effect on sediment texture and heavy metals. Enforcement of control of excess bottom trawlers and popularization of semi pelagic trawls designed to operate a little distance above the sea bottom for off bottom resources will minimize disturbance on the sea bottom. Training and creating awareness in responsible fishing should be made mandatory requirements, to the coastal communities. They should be made wardens to protect the valuable resources for the benefit of sustainability. To protect the biodiversity and ecosystem health, the imminent need is to survey and make catalogue, identification of sensitive areas or hot spots and to adopt management strategies for the conservation and biodiversity protection of benthic fauna. The present study is a pioneering work carried out along Veraval coast. This thesis will provide a major fillip to the studies on impact of bottom trawling on the benthic fauna along the coast of India.

Tropical Mesoscale Convective Systems and Associated Energetics : Observational and Modeling Studies

The main purpose of the thesis is to improve the state of knowledge and understanding of the physical structure of the TMCS and its short range prediction. The present study principally addresses the fine structure, dynamics and microphysics of severe convective storms.The structure and dynamics of the Tropical cloud clusters over Indian region is not well understood. The observational cases discussed in the thesis are limited to the temperature and humidity observations. We propose a mesoscale observational network along with all the available Doppler radars and other conventional and non—conventional observations. Simultaneous observations with DWR, VHF and UHF radars of the same cloud system will provide new insight into the dynamics and microphysics of the clouds. More cases have to be studied in detail to obtain climatology of the storm type passing over tropical Indian region. These observational data sets provide wide variety of information to be assimilated to the mesoscale data assimilation system and can be used to force CSRM.The gravity wave generation and stratosphere troposphere exchange (STE) processes associated with convection gained a great deal of attention to modem science and meteorologist. Round the clock observations using VHF and UHF radars along with supplementary data sets like DWR, satellite, GPS/Radiosondes, meteorological rockets and aircrafl observations is needed to explore the role of convection and associated energetics in detail.