Studies of stability of fluid flowa using variational methods

The study of stability problems is relevant to the study of structure of a physical system. It 1S particularly important when it is not possible to probe into its interior and obtain information on its structure by a direct method. The thesis states about stability theory that has become of dominant importance in the study of dynamical systems. and has many applications in basic fields like meteorology, oceanography, astrophysics and geophysics- to mention few of them. The definition of stability was found useful 1n many situations, but inadequate in many others so that a host of other important concepts have been introduced in past many years which are more or less related to the first definition and to the common sense meaning of stability. In recent years the theoretical developments in the studies of instabilities and turbulence have been as profound as the developments in experimental methods. The study here Points to a new direction for stability studies based on Lagrangian formulation instead of the Hamiltonian formulation used by other authors.

Studies on fungal flora with special reference to Yeasts in the Cochin backwaters

Man's concern with environmental deterioration is one of the major reasons for the increased interest in marine and estuarine microbes. Microbes form an important link in the biogeochemical cycling and their cyclinq activites often determine to a large measure the potential productivity of an ecosystem In the recycling of the nutrients in the estuary, bacteria and fungi therefore play a particularly significant role.The allochthonous plant materials contain biopolymers such as cellulose, lignin, humus etc., that are difficult to degrade into simpler substances. The fungi have the ability to degrade _substances, thereby making them available for cycling within the system. The present study is devoted to find the composition and the activity of myco populations of Cochin backwater. For convenience the thesis is divided into eight chapters. The opening chapter briefly reviews the literature and projects the importance of work and the main objectives. Second chapter discusses the materials and methods. In the third chapter the systematic and taxonomy of estuarine yeasts are examined in detail since this information is scarcely available for our waters. The general ecological aspects of the yeasts and filamentous fungi in the area of study are examined in the fourth chapter using appropriate statistical techniques. A special reference to the fungi in a small mangrove ecosystem is attempted in the fifth chapter. The biochemical studies are discussed in the sixth chapter and the penultimate chapter provides an overall discussion. In the last chapter the summary of the work is presented.

Studies on vibrio spp. in juveniles of penaeus indicus in culture systems

The present study is carried out to understand (i) the incidence and occurrence of species of Vibrio in different culture systems in and around Cochin, (ii) characteristics of vibrios isolates, their ecology including growth response to various hydrological parameters, sensitivity to about 40 antibiotics, and (iii) role of physico-chemical parameters in pathogenicity of vibrios, etc. and the results emerged from the investigations are important and encouraging for better understanding of the 'vibriosis' in the culture systems to develop remedial measures to control diseases. The Thesis begins with an “Introduction” followed by “A review of literature” on diseases of penaeid shrimps with particular reference to 'vibriosis' and “Material and methods” which details with the methods and procedures followed in the experiments and analyses of data. This Thesis consists of three chapters. Chapter Ideals with the incidence and ecology of Vibrio spp. in water, sediment and in juveniles of the Indian white prawn Penaeus indicus in the culture systems. In Chapter 2, characteristics of vibrio isolates including growth response to various levels oftemperature, salinity and pl 1, sensitivity to 40 antibiotics and minimal inhibitory concentration tests are detailed.e out-breaks. The Chapter 3 discusses the role of physico-chemical parameters in the incidence, seasonal abundance of Vibrio spp. and in 'vibriosis'. A summary of the whole work and list of references are also included at the end. This study gives a detailed information regarding the incidence and ecology of vibrios in the culture systems. their characteristics and pathogenicity

Studies on the reproductive physiology of the green tiger prawn Penaeus (penaeus) semisulcatus de Haan

A study of the reproductive physiology of P. (P). semisulcatus wasundertaken as this information is an essential prerequisite for brood stock development for hatchery operations, and the results are embodied in this thesis. The thesis is presented in seven chapters. The protein, lipid and carbohydrate contents of ovary were estimated for the different vitellogenic phases. The protein, lipid, carbohydrate and cholesterol contents were estimated in testes and spermatophore.The thesis present the results of induced maturation experiments by eyestalk ablation, CNS extract injection and UV rays application on immature female prawns.

Studies on the Composition and Structure of Palm Oil Glycerides

During the last couple of decades, the oil palm has emerged as the second largest source of edible oil in the world. Recently oil palm has been introduced commercially in India to augment edible oil supply in the country. Currently, about 10,000 hectares are under oil palm cultivation in India, and it is envisaged to cover about 6 lakh hectares in the coming years. Though oil palm is a major commercial oil crop, not much basic information on the lipids of the fruit (the source of palm oil) is available even where oil palm is cultivated in a very large scale. Being a new crop to India, it is of paramount importance to understand the basic chemistry/biochemistry of the lipids, which in turn, may find practical applications in the area of processing and product development. The present investigation entitled "Studies on the Composition and Structure of Palm Oil Glycerides" was designed with a view to elucidate the lipid composition and structure under conditions such as fruit development and processing.

Studies on the benthose of the mud bank regions of the Kerala coast

There is very little information on the subtidal bottom fauna of the shelf regions in the seas around India. What little is known is restricted to macro benthos. The paucity of the work on bottom fauna and the importance of mud banks in the fishery of the South West Coast of India has initiated the present study. Attempts have been made to obtain a picture of the bottom fauna of a mud bank region of the Kerala Coast. The difficulties involved in the sampling and analysis, especially the availability of a suitable vessel during the S.W. Monsoon, resulted in the work being restricted mainly to the Narakal mud bank region 6 Km. north of Cochin Detailed sampling is conducted using grab, dredge and to a small extent beam trawl, to assess the qualitative and quantitative nature of the macro benthos. Important species contributing to the fauna are identified and the standing crop estimated for different seasons. The meiobenthos was studied using core samples taken from the grab. Animals were identified to the major taxa. Standing crop of meiobenthos and the quantitative importance of different groups were also studied. The data collected have been interpreted and discussed. As an understanding of the physico-chemical aspects of the environment is essential in order to obtain a true picture of the benthos, attempts were made in this direction. Environmental parameters such as temperature of the sediment, salinity, temperature, and dissolved oxygen in the overlying water were studied .during the period of benthos investigation. Monthly observations on the dissolved inorganic and organic phosphorus in the area of investigation have been made. The physico-chemical nature of the sediment was also studied. Influence of these ecological variables on the bottom fauna is discussed.

Transition metal complexes derived from ketone based N(4)-substituted thiosemicarbazones: Crystal structures and spectral studies

Thiosemicarbazones have recently attracted considerable attention due to their ability to form tridentate chelates with transition metal ions through either two nitrogen and sulfur atoms, N–N–S or oxygen, nitrogen and sulfur atoms, O–N–S. Considerable interest in thiosemicarbazones and their transition metal complexes has also grown in the areas of biology and chemistry due to biological activities such as antitumoral, fungicidal, bactericidal, antiviral and nonlinear optical properties. They have been used for metal analyses, for device applications related to telecommunications, optical computing, storage and information processing.The versatile applications of metal complexes of thiosemicarbazones in various fields prompted us to synthesize the tridentate NNS-donor thiosemicarbazones and their metal complexes. As a part of our studies on transition metal complexes with these ligands, the researcher undertook the current work with the following objectives. 1. To synthesize and physico-chemically characterize the following thiosemicarbazone ligands: a. Di-2-pyridyl ketone-N(4)-methyl thiosemicarbazone (HDpyMeTsc) b. Di-2-pyridyl ketone-N(4)-ethyl thiosemicarbazone (HDpyETsc) 2. To synthesize oxovanadium(IV), manganese(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes using the synthesized thiosemicarbazones as principal ligands and some anionic coligands. 3. To study the coordination modes of the ligands in metal complexes by using different physicochemical methods like partial elemental analysis, thermogravimetry and by different spectroscopic techniques. 4. To establish the structure of compounds by single crystal XRD studies

Studies on lipid nutrition in larvae and juveniles of the indian white prawn penaeus indicus h. milne edwards

Recent studies with prawns indicate that their growth, metamorphosis, maturation and moulting are affected by the typo and level of lipids supplied in the diets. Despite the recognition of the importance of lipids in the diets of prawns there is no information on the essentiality and quantitative lipid requirements of Indian penaeid prawns. Therefore during the present study about 24 laboratory experiments were conducted to determine the essentiality and dietary requirements of total lipids, phoapholipida, fatty acids cholestrol, and to ascertain the nutritional value of natural lipid sources for the larvae, post-larvae tad juveniles of one of the most suitable cultivable species of panaeid prans. All the experiments were conducted in the laboratory following standard procedures, using isonitrogen and approaximately isocaloric purified diets. Changes were made in tha ingridients as required for specific requirements. For the larvae diets of particle size < 37) were fed, For the postlarvae and juveniles pellet feed was given. while data on survival and growth of larvae and pout-larvae 1-10 were recorded, data were collected on the survival, growth, food conversion ratio, protein efficiency ratio and biochemical composition at the body for post-larva 11-25 and juveniles. The influence ot fatty acid pattern of dietary lipid sources on the fatty acids profile of prawns were also studied in the case of juvenile prawns. Analysis of variance andleast significant differences test were employed to determine the significant differences between treatments in the observed parameters with the help of a newlett Packard master computer.

Studies on molecular structure and properties using microwave and infrared spectral data

The major objective of the thesis is essentially to evolve and apply certain computational procedures to evaluate the structure and properties of some simple polyatomic molecules making use of spectroscopic data available from the literature. It must be said that though there is dwindling interest in recent times in such analyses, there exists tremendous scope and utility for attempting such calculations as the precision and reliability of'experimental techniques in spectroscopy have increased vastly due to enormous sophistication of the instruments used for these measurements. In the present thesis an attempt is made to extract maximum amount of information regarding the geometrical structure and interatmic forces of simple molecules from the experimental data on microwave and infrared spectra of these molecules

Studies on the ecology and productivity of saline lagoon

A perusal of the literature shows that most of the earlier works on the ecology and productivity from the Indian waters have been confined to the estuarine ecosystms and contiguous neritic and oceanic water bodies. Although some information is available on certain aspects of the envirornental parameters from the ‘coastal lagoon ecosystem‘, there is hardly any indepth study on the ecological and productivity problems from "derlict saline lagoonal environment" in India . In view of this, the researcher undertook a study on the subject "ecology and productivity“ of a typical “coastal saline lagoon"(Pilla;headan lagoon) situated along the southeast coast of India for a period of two years!-N11, 1982 to June, 1984) , and the results of the investigations are embodied in the present thesis entitled "studies on the ecology and productivity of saline lagoon‘.

Studies on the freshwater copepod fish parasites of Kerala

Studies on parasitic copepods from freshwater fishes are still in its infancy. In recent years, there- is a renewed enthusiasm in the study of freshwater fish parasites due to rapidly increasing aquaculture practices. The importance of diseases and their control assumes great significance because of the adverse impact of diseases on fish production and its economy. Copepods are one of the most harmful parasites of freshwater fishes. Reports on the damages caused by copepod parasites from different parts on the world are increasing alarmingly. But the information on parasitic copepods of freshwater fishes in India is quite meagre. Knowledge regarding this group of parasites, their Biology and pathology from Kerala. is lacking. The thesis consists of five chapters. The first chapter is a general introduction which deals with the review of literature on various aspects of parasitic copepods viz; systematics, life history, host-parasite relationship, ecology, pathogenicity, prophylaxis and control measures. Systematics of parasitic copepods of freshwater fishes collected during the present study forms the second chapter. The third chapter deals with the life cycle study of the new Lernaeid copepod, Lernaea osphronemi. The fourth chapter contains host-parasite relationship. ecology and treatment of ‘the’ new species of Lernaea On Osphronemus goramy. General observations and a summary of the entire work constitute the fifth chapter

Studies on genetic polymorphism in Santalum Album L.

Loss of natural sandal populations due to illicit felling, forest encroachment and spike disease have an adverse effect on genetic diversity of the species. To initiate any genetic improvement programme in sandal, a precise understanding of the population genetic diversity structure is essential. The concern over the loss of genetic variability in sandal is particularly critical, as there is hardly any information regarding the diversity status of the natural populations. Identifying fast growing, disease resistant, oil rich sandal trees through breeding and their mass multiplication for afforestation are the best method for ensuring sustainable supply of superior sandalwood. The healthy sandal trees existing in heavily spike diseased area can be used as a promising starting point for any such breeding programme (Venkatesh, 1978). So far, no genetic information is available regarding the resistant nature of spike disease evaded trees left in heavily infected patches. The high rate of depletion of the superior trees in South Indian sandal reserves due to illegal felling and spike disease has necessitated an urgent need for conservation of the surviving trees.Widespread occurrence of spike disease in Marayoor forest reserve was reported in 1981 (Ghosh and Balasundaran, 1995). Because of the high density of trees and varying intensity of spike disease, Marayoor sandal population was found to be ideal for experimental studies in sandal (Ghosh et al., 1985). Fifteen trees of reserve 51 of Marayoor range had been selected as candidate plus trees for growth and spike disease evasion . These trees have been selected for mass multiplication through tissue culture technique.

Studies on rubber compositions as passive acoustic materials in underwater electro acoustic transducer technology-and their aging characteristics

Rubber has become an indispensable material in Ocean technology. Rubber components play critical roles such as sealing, damping, environmental protection, electrical insulation etc. in most under water engineering applications. Technology driven innovations in electro acoustic transducers and other sophisticated end uses have enabled quantum jump in the quality and reliability of rubber components. Under water electro acoustic transducers use rubbers as a critical material in their construction. Work in this field has lead to highly reliable and high performance materials which has enhanced service life of transducers to the extent of 1015 years. Present work concentrates on these materials. Conventional rubbers are inadequate to meet many of the stringent functional of the requirements. There exists large gap of information in the rubber technology of under water rubbers, particularly in the context of under water electro acoustic transducers. Present study is towards filling up the gaps of information in this crucial area. The research work has been in the area of compounding and characterisation of rubbers for use in under water electro acoustic transducers. The study also covers specific material system such as encapsulation material, baffle material, seal material, etc. Life prediction techniques of under water rubbers in general has been established with reference to more than one functional property. This thesis is divided into 6 chapters.

Studies on meroplankton

Plankton community, drawn from a vary wide variety of animal phyla, formed the basic food supply of marine life and indicators of water mass. The term meroplankton generally referred to that portion of the zooplankton which is transient in nature, remaining rest of their lives in the nektonic or benthic environment. This group was selected for intensive studies, considering the role of meroplankton in the economy of the sea and the scarcity of literature on them from the Indian Ocean. The preser .udy besides providing information regarding the fixation and preservation !e _ iniques and biochemical aspects of tropical meroplankton, also consolidates information regarding their zoogeography in the Indian Ocean region, with a view to amplifying the limited information available from this area. The distribution studies are based on the collections made during the International Indian Ocean Expedition (1960-65), whereas the material for preservation and biochemical studies was collected from the coastal waters during 1968-1978. Salient features:- 2% of formaldehyde buffered with 2% borax, added to the plankton in the ratio of 9:1 was found the best fixative. On fixation the plankton underwent shrinkage due to loss of 15 to 87% water. Addition of antioxidants prevented colour fading. Narcotization by different specific reagents prior to fixation reduced distortions due to violent reaction and improved morphological conditions. One percent formaldehyde solution in sea water buffered with borax or neutralised with calcium carbonate perfectly preserved majority of meroplankton. Equally good was one percent propylene phenoxetol buffered with borax. Biochemical compostion of vaioous taxa showed variations according to their age class, size groups metamorphosing stage, feeding mechanism, type of organism fed and time of collection. General distribution studies of 4 meroplankton taxa - Anthozoan larvae, cirripedia larvae, sipunculoid larvae and gastropod larvae stowed abundance in the coastal areas especially during the SW monsoon period. Based on the larval distribution different zoo-geographical areas in the Indian Ocean are differentiated.

Studies on the reproductive physiology of lazes calcarifer (BLOCH)

At present, there is paucity of information regarding the breeding biology, especially from southeastern region, which differs in its climatic features from northeastern coastal areas, where some attempts have been made to study the biology of the fish, though not documented in detail (Jhingran and Natarajan, I969; Patnaik and Jena, 1976; Kowtal, 1977; Roy e_t _a_l_., I977). The present work, first to undertake detailed investigation into reproductive aspects of the fish from India is not only confined to biology, but extend to the study on histological as well as physiological changes in the processes associated with natural reproductive cycle. The main objective of the study is to develop a background for the standardisation of subsequent artificial propagation techniques for the Sea Dass The thesis is presented in three chapters. The first chapter; general introduction, surveys the literature pertaining to the status of research on Lates calcarifer with specific reference to reproduction and acquaculture. The second chapter entitled, materials and methods gives description regarding collection of specimens as well as samples in addition to the various analytical methodologies employed during the study.