Aqueous Sol-gel Process for Nanocrystalline Photocatalytic Titania, Transparent Functional Coatings and Ceramic Membrane

The present thesis develops from the point of view of titania sol-gel chemistry and an attempt is made to address the modification of the process for better photoactive titania by selective doping and also demonstration of utilization of the process for the preparation of supported membranes and self cleaning films.A general introduction to nanomaterials, nanocrystalline titania and sol-gel chemistry are presented in the first chapter. A brief and updated literature review on sol-gel titania, with special emphasis on catalytic and photocatalytic properties and anatase to rutile transformation are covered. Based on critical assessment of the reported information the present research problem has been defined.The second chapter describes a new aqueous sol-gel method for the preparation of nanocrystalline titania using titanyl sulphate as precursor. This approach is novel since no earlier work has been reported in the same lines proposed here. The sol-gel process has been followed at each step using particle size, zeta potential measurements on the sol and thermal analysis of the resultant gel. The prepared powders were then characterized using X-ray diffraction, FTIR, BET surface area analysis and transmission electron microscopy.The third chapter presents a detailed discussion on the physico-chemical characterization of the aqueous sol-gel derived doped titania. The effect of dopants such as tantalum, gadolinium and ytterbium on the anatase to rutile phase transformation, surface area as well as their influence on photoactivity is also included. The fourth chapter demonstrates application of the aqueous sol-gel method in developing titania coatings on porous alumina substrates for controlling the poresize for use as membrane elements in ultrafiltration. Thin coatings having ~50 nm thickness and transparency of ~90% developed on glass surface were tested successfully for self cleaning applications.

Haematology of Fenneropenaeus indicus in response to environmental alterations and microbial infections

Aquaculture has developed to become one of the fastest growing food producing sectors in the world.Today India is one among the major shrimp producing countries in the world.There are extensive and intensive shrimp culture practices. In extensive shrimp culture, shrimps are stocked at low densities (< 25 PLs m'2)in large ponds or tidal enclosures in which little or no management is exercised or possible. Farmers depend almost entirely on natural conditions in extensive cultures. Intensive shrimp culture is carried out in high densities (>200 PLs m'2). Much of the world shrimp production still comes from extensive culture.There is a growing demand for fish and marine products for human and animal consumption. This demand has led to rapid growth of aquaculture, which some times has been accompanied by ecological impacts and economic loss due to diseases. The expansion of shrimp culture always accompanies local environmental degradation and occurrence of diseases.Disease out breaks is recognised as a significant constraint to aquaculture production. Environmental factors, water quality, pollution due to effluent discharge and pathogenic invasion due to vertical and horizontal transmission are the main causes of shrimp disease out breaks. Nutritional imbalance, toxicant and other pollutants also account for the onset of diseases. pathogens include viruses, bacteria, fungi and parasites.Viruses are the most economically significant pathogens of the cultured shrimps world wide. Disease control in shrimp aquaculture should focus first on preventive measures for eliminating disease promoting factors.ln order to design prophylactic and proactive measures against shrimp diseases, it is mandatory to understand the immune make up of the cultivable species, its optimum culture conditions and the physico chemical parameters of the rearing environment. It has been proven beyond doubt that disease is an end result of complex interaction of environment, pathogen and the host animal. The aquatic environment is abounded with infectious microbes.The transmission of disease in this environment is extremely easy, especially under dense, culture conditions. Therefore, a better understanding of the immune responses of the cultured animal in relation to its environmental alterations and microbial invasions is essential indevising strategic measures against aquaculture loss due to diseases. This study accentuate the importance of proper and regular health monitoring in shrimps employing the most appropriate haematological biomarkers for application of suitable prophylactic measures in order to avoid serious health hazards in shrimp culture systems.

Fish habitats and species assemblage in the selected rivers of Kerala and investigation on life history traits of Puntius carnaticus(Jerdon,1849)

This thesis entitled Fish habitats and species assemblage in the selected rivers of kerala and investigation on life history traits of puntius carnaticus (JERDON,1849). Ecology is a new and exceedingly complex field of study, even though its concept was recognized by the Apostles in their use of the phrase ‘all flesh is grass.central role to play both in order to understand better the biodiversity phenomenon and to be able to draw up clear guidelines for careful resource management. In a review by WWF, IUCN and UNEP on the ways of conserving genetic diversity of freshwater fish it was recommended that the best way to conserve species diversity is to conserve habitat.The habitat studies in freshwater ecosystems are very essential for the proper understanding and management of human impact on fish diversity, to study the relationship between habitat variables and fish species assemblage structure, quantification of ecosystem degradation, habitat quality and biotic integrity of the ecosystems, development of habitat suitability index (I-ISI) models and classification of river reaches based on their physico-chemical properties. Therefore in the present study an attempt was made to assess the biodiversity potential and the relationship between habitat variables and fish species assemblage structure in six major river systems of Kerala which would be very useful in impressing upon the seriousness of habitat degradIn the present study, in Kabbini river system 15 locations encompassing between 721 946m above MSL were surveyed.ation and biotic devastation undergone in the major river systems of Kerala.During the present study the Habitat Quality Score (HQ) developed by the Ohio EPA was applied for the first time in India.The result of the present study revealed that, among various variables analysed, altitude has a very significant influence in deciding the fish diversity in six major river systems of Kerala. The fish diversity studied on the basis of Shanon-Weiner and Simpson diversity indices revealed that even though some minor variations occur with the suitability and complexity of habitats, the altitude showed inverse relationship with fish diversity.The present study revealed that the National Policy on the interlinking of rivers would permanently alter the HSI indices of the above mentioned fish species, which are now solely protected by the individuality of the rivers where their limited occurrence was notice.

Vanadia Supported on Rice Husk Silica Promoted Rare Earth Oxides

The selective oxidation of alkylaromatics is one of the main processes since the reaction products are important as intermediates in numerous industrial organic chemicals. Side-chain oxidation of alkyl aromatic compounds catalyzed by heterogeneous catalysts using cleaner peroxide oxidants is an especially attractive goal since classical synthetic laboratory procedures preferably use permanganate or acid dichromate as stoichiometric oxidants. In spite of many studies, there are very few which use hydrogen peroxide as a source of oxygen in the C-H activation of alkanes. Eflective utilization of ethylbenzene, available in the xylene stream of the petrochemical industry to more value added products is a promising one in chemical industry. The oxidation products of ethylbenzene are widely employed as intermediates in organic, steroid and resin synthesis.

Studies on the pathobiology of penaeid larvae and postlarvae

The thesis presents the results of the studies carried out on certain diseases encountered in the larvae and postlarvae of penaeid prawns raised in the hatcheries at Cochin, Madras and Mandapam Camp during September 1985- April 1988. In the preliminary survey carried out to understand the common diseases occurring in the penaeid larvae and postlarvae, seven cases of diseases and abnormalities were encountered. These included ciliate infestation, Nit_zschia closteriurn infestation, parasitic protozoaninfection, parasitic dinoflagellate infection, appendage necrosis, heteromorphic eye and abnormal eggs and deformed nauplii .The clinical signs, seasonal occurrence and incidence of each of the above cases were provided along with the information on environmental factors such as salinity, dissolved oxygen, temperature and pH of the rearing medium. The Thésis is presented in nine chapters. Chapter 1 surveys the literature on the diseases of penaeid larvae, postlarvae and adult prawns from India and abroad. This is followed by a chapter on the material and methods employed during the present investigation. In the third chapter, seven cases of diseases and abnormalities encountered in the larvae and postlarvae of Penaeus indicus and p. semisulcatus during the survey carried out in the hatcheries located at different centres of Central‘ Marine Fisheries Research Institute are presented and discussed .A bacterium responsible for appendage necrosis was isolated and its taxonomy was studied. It was Gram-negative, fermentative and motile rod. It was sensitive to vibriostatic compound, 0/129. This bacterium was found to be a new isolate of vibrio on the basis of its morphological, biological, physiological and biochemical characters and comparison of these characters with those described for other related vibrios. This new isolate of vibrio was deposited in vibro Referrence Laboratory, Centres for Disease Control, Georgia, U.S.A. and coded as vibrio sp. 2448-88.

Studies on amylolytic bacteria in Cochin backwaters

This thesis Entitled Studies on amylolytic bacteria in cochin backwaters.This thesis presents a detailed account of the disribution of amylolytic bacteria in water. sediment. fishes ( Etroplus suratensis and Liza parsia) • prawns ( Penaeus indicus and Metapenaeus dobsoni) and clams ( Sunetta scripta and Meretrix casta) from Cochin backwaters. genera-wise distribution of amylolytic bacteria, ability of selected strains to grow and produce amylase at various physico-chemical conditions. Regulation of amylase synthesis anrt characters of amylases producer by these halophilic bacteria.Amylolytic bacteria are distributed widely in water. sediment. fishes. prawns and clams of Cochin back waters. 53% of the total isolates tested were capable of producing amylase. Maximum number of arnylolytic bacteria were present in Metapenaeus dobsoni. In general, the gut region of aquatic animals harboured more amylolytic bacteria than the gill or surface. These bacteria may help in the digestion of starch present in their food.Presence of ions in the medium was found to be essential for growth and amylase production. It was found that this ionic requirement is not highly specific. Sorlium chloride could be replaced by potassium chloride. or magnesium chloride to some extent I without affecting growth and amylase production. The important function of these ions may be to maintain the osmotic balance between the cells and their environment.All the isolates showed the ability to grow and produce amylase using raw-starches from cassava. plantain and potato .This property suggests their role in the rdegradation of native starches in the environment

Studies on the systematics and biology of the fisheries of the Vembanad lake

The thesis documents a comprehensive systematic account of Vembenad lake fishes and to study the effect of physico-chemical parameters on the distribution and abundance of fishes in the lake. This study is expected to advance the knowledge on the biological aspects of two commercially important fishes of the lake which are very desirable for brackish water fish farming. Additionally, the results of the studies on the ecology as habitat, occurrence, season and abundance of all the recorded fishes of the lake end the commercially important fish species of the lake are also incorporated. A general appraisal on the detrimental factors which are adversely affecting the fisheries resources of the lake are presented and some measures of conservation are also suggested. The results of the present study are helpful in formulating suitable schemes for management of parts of the Vembenad lake for capture and culture fisheries

Microbial production of antibiotics from mangrove ecosystem

The present study on "Microbial production of antibiotics from mangrove ecosystem” was carried out for a period of one year in four selected Stations, Mangalavana, Narakkal, Puthuvyppu and light house area of Puthuvyppu (9°55' — 10°10'N and 76°10‘ - 76°20'E) from January to December 1991. Though much emphasis has been given to occurrence and distribution of actinomycetes, an attempt was also made to understand the distribution patterns of other micro flora in the sediments. Data on physico-chemical parameters were also collected to find out their relationship if any with the microflora. The principle interest of the present investigation is to determineseasonal variations of antagonistic actinomycetes in selected mangrove ecosystem. The microbial interrelationship in mangrove sediments was found out by constructing the ratio between bacteria and actinomycetes, bacteria and fungi, fungi and actinomycetes. In addition temperature, pH, salinity, dissolved oxygen and organic carbon were determined seasonally and their possible relationship was statistically analyzed and the results are presented. Isolated actinomycetes were subjected to cross streak assay to know their nature of antibiotic activity against test fish pathogens and crude antibiotics were extracted from selected isolates and their inhibitory activity is studied and the results are discussed.

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 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.

Benthic ecology of selected prawn culture fields and ponds near Cochin

The thesis on the"Benthic ecology of selected prawn culture fields and ponds near Cochin” was taken up with a view to provide information on the qualitative and quantitative distribution of benthos and their relationships to prawnproduction of different culture ecosystems and to the physico-chemical parameters influencing their production. A two-year observation was carried out in nine selected prawn culture systems including perennial ponds (stations 1 to 4) seasonal fields (stations 5 to 7) and contiguous canals (stations 8 and 9) during December 1988 to November 1989. All macro- and meiobenthic organisms contributing to the faua were identified and their abundance, distribution, diversity, biomass and trophic relationships between benthos and prawns were studied. The environmental variables studied were temperature pH, salinity, dissolved oxygen, alkalinity, nitrite-nitrogen, nitrate-nitrogen, amonianitrogen, phosphate and silicate of bottom water and organic carbon and texture of the soil The thesis is presented in 4 Chapters. Chapter I presents an’ INTRODUCTION to the topic of study and a review of relevant works to bring an awareness to the present status of research in benthos and benthic ecology. Chapter 11, MATERIALS AND MTHODS, includes the techniques of sampling, preservation of samples and methods of analyses of various physico-chemical factors and area covered under the study is also given in this chapter. Chapter III, HYDROGRAPHY deals with the results of investigation and discussion onthe physico-chemical parameters of water and Chapter IV, SEDIMENT covers the sedimentoloical characteristics of the different culture systems followed by a detailed discussion. Chapter V, BOTTOM FAUNA presents an account on the various aspects of benthos and benthic ecology and the details of prawn production. A discussion on the overall assessment of interrelations between abiotic and biotic factors is given in Chapter VI, DISCUSSION. A critical evaluation of the implication of benthic production on prawn production under culture conditions and trophic relationships are also included in this chapter. An executive SUMMARY of the observations made during this study is presented in the final section of the thesis .

Macrobenthos of a tropical estuary

In this thesis a detailed sampling is conducted using grabs and dredges to access the qualitative and quantitative nature of the macrobenthos. A11 the animal contributing to the fauna are identified and their pattern of distribution and seasonal abundance are discussed. Affinity and diversity of polychaete fauna have also been studied. Importance of different benthic forms and their contribution to the standing crop are studied in detail. Trophic relationship between macrofauna and botton feeding commercially important fishes and prawns are also given attention. The physico-chemical aspects or the environment have been studied and their relation to the distribution and abundance of bottom fauna has been discussed. Environmental parameters such as temperature. salinity and dissolved oxygen. both in bottom and in the overlying waters. and rainfall were studied along with the benthos investigations. The physico-chemical nature of the sediments was also subjected to investigation. Influence of all those ecological parameters on the bottom fauna is discussed. A detailed quantitative faunal list of maorobenthio species and a brief systematic account of the polychaeta are also given.

Water Quality Variation, its Influence on Drinking Water Treatment and Remedial Measures - A Case Study of Peechi reservoir, Thrissur, Kerala

The Kerala Water Authority requested the School of Environmental Studies to carry out investigations on the mechanism of sporadic mobilization of iron and odour in the raw water drawn to the drinking water treatment plant. The currently used treatment process failed to remove iron completely. This led to problems in the filter and complaints of taste and colour due to iron in the finished water. The sporadic nature of the problem itself made the trouble shooting difficult. The problem was looked in from three points of view. 1. Influence of environmental (climatic) conditions on the dynamics of the relevant basin of the reservoir. 2. Influence of the physical dynamics on the physico — chemical quality of water. 3. Identification of cost-effective treatment processes to suit the existing plant. Since the problem emerged only during the post- monsoon to pre-monsoon months, a related problem was investigated, namely, influence of anions on the oxidation of Fe(II) in natural waters by air. This is presented in Part II of the dissertation.

Studies on the treatment of effluents from natural rubber processing units

The present study was undertaken to evaluate the effectiveness of a few physico-chemical and biological methods for the treatment of effluents from natural rubber processing units. The overall objective of this study is to evaluate the effectiveness of certain physico-chemical and biological methods for the treatment of effluents from natural rubber processing units. survey of the chemical characteristics of the effluents discharged from rubber processing units showed that the effluents from latex concentration units were the most polluting

Seoimentology And Geochemistiiy Of Some Selected Mangrove Ecosystems Of Kerala, Southwest Coast Of India

As a result of the issues of care and conservation and sustainable utilisation, the proper management of mangrove forests have become more pressing than ever. Much recent ecological and toxicological debate has been centered around the question of validity of making predictions about the future of mangrove ecosystemas a result of the newly evolved environmental policy. Though muchinformation exist on the biodiversity, floristic composition and characteristics, geographical distribution and uses of mangroves, systematic documentation of the various sedimentological and geochemical phenomena in relation to the mangrove flora are scarce. Hazardous, persistent, man-made chemicals and waste produces are entering the mangrove ecosystem at from the adjacent watersheds which strengthened alarming rates the indispensible need for further researches on the environmental behaviours, fate and the effect of such products. Studies on the effect of heavy metals, pesticides and the other toxic signals through bioassay and toxicity tests on mangrove species as well as in sediments definitely will furnish ample clues to establish the actual operative mechanisms of these environments. A thorough review of literature made in this angle reveals that some attempts have already been initiated the world over the record the physico-chemical characteristics of major abiotic components such as sediments and water of many mangrove ecosystem, however, adequate information is lacking in the Indian Environmental Science scenario. The present investigation is an attempt to record the sedimentological, mineralogical and geochemical characteristics of sediments as well as the heavy metal enrichment in the various species ofmangrove flora of three important mangrove ecosystems of Kerala, located at Veli (SouthKerala), Kochi (Central Kerala) and Kannur (North Kerala). The results of the above investigation have been analysed statistically, discussed based on the available literature and presented in this thesis under seven chapters