| URI: | http://dyuthi.cusat.ac.in/purl/1016 |
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| Annam Chacko 1987.pdf | (263.5Kb) |
| Abstract: | The thesis entitled studies on the synthesis and transformations of a few 2(3H)- and 3(2H)- furanones. Furanones represent an interesting class of heterocyclic compounds, which constitute the central ring system of many natural products. The derivatives of furan is divided, depending on their structure 2(3H)-furanones(I), 2(5H)-furanones(II), and 3(2H)-furanones(III). Systems I&II are unsatured gama lactones known as ‘butenolides’. Compounds of this type also known as ‘crotonolactones’ based on the parent crotonic acid. In conclusion a number of 2(3H)-and 3(2H)- furanones were synthesized from dibenzoylalkene precursors and were characterized on the basis of spectral analytical and X-ray data. On direct irradiation 3,3-bis(4-chloropheneyl)-5-aryl-3H-furan -2-ones underwent decarbonylation to yield the corresponding alpha, beta- unsaturated carbonyl compounds and upon sensitized irradiation they underwent dimersation arising through a 2+2 cycloaddition reaction. Our studies on 3(2H)-furanones revealed that these compounds are thermally stable, while they undergo extensive decomposition to intractable mixtures under the influence of light. Similarly, the novel dibenzoylalkenes- type systems containing hetroatomatic rings synthesized by us also underwent extensive decomposition under the influence of heat. Some of the 3(2H)-furanones synthesized by us exhibit remarkable anti-proliferative activity. |
| URI: | http://dyuthi.cusat.ac.in/purl/96 |
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| Dyuthi-T0256.pdf | (2.743Mb) |
| Abstract: | In this thesis, we report our endeavours in the synthesis of a few polycyclic compounds. We were interested in the synthesis of a few bicyclic compounds designed to undergo interesting photochemical transformations including tripletmediated di-π-methane rearrangement and/or competing singlet-mediated electrocyclic reactions. Our target molecules have "inbuilt" structural features which will potentially alter the photochemistry of the substrate under consideration.The present investigation was undertaken to test our hypothesis on selective intramolecular quenching of singlet or triplet excited states of molecules.We adopted Dies-Alder reaction for the synthesis of several of the bicyclic compounds we were interested in. Some of the precursor dienes synthesised by us are capable of undergoing intramolecular cycloaddition reactions as well. So, it was important to delineate the conditions and structural features that will enable a particular molecule to undergo intermolecular and intramolecular Dies-Alder reaction when treated with a suitable dienophile.Though, the main focus of this thesis is on the synthesis of bicyclic and tricyclic systems capable of undergoing di-π-methane rearrangement, in the last chapter of this thesis, we describe our findings on the synthesis of a few dispirocompounds. These systems were encountered as unexpected products in the attempted synthesis of novel dibenzoylalkene-type systems. Consequently, a brief survey on the synthesis and transformations of dibenzoylalkenes is also included as an integral part of this thesis. |
| Description: | Department of Applied Chemistry, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2054 |
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| Dyuthi-T0477.pdf | (4.280Mb) |
| Abstract: | 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. |
| URI: | http://dyuthi.cusat.ac.in/purl/15 |
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| Dyuthi-T0252.pdf | (1.761Mb) |
| Abstract: | 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 |
| URI: | http://dyuthi.cusat.ac.in/purl/994 |
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| Binoy Jose Mar 2000 chap 1,2,3,4,5,6&7.pdf | (46.96Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1021 |
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| Unnikrishnan P A 1989.pdf | (348.0Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1737 |
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| Dyuthi-T0261.pdf | (2.799Mb) |
| Abstract: | In the present work different new approaches for the synthesis of Vitamin A are investigated. In these synthetic schemes, all the twenty carbon atoms of the target molecule are derived either fully from components isolated from common essential oils or partially from commercially available materials. By retrosynthetic analysis, Vitamin A molecule can be disconnected into a cyclic and a linear unit. Different methods for the synthesis of the linear and the cyclic components are described. The monoterpenes, geraniol and citral, major constituents of palmarosa and lemongrass oils, have the required basic carbon framework for consideration as starting materials for the synthesis of Vitamin A. The potential of these easily available naturally occurring compounds as promising starting materials for Vitamin A synthesis is demonstrated. Organoselenium and organosulfur mediated functional group transformations for the synthesis of the functionalised conjugated C10 linear components (ie., the dimethyloctatriene derivatives) are reported. The classical approaches as well as the attempted preparation of cyclic C10 and C13 units employed in the present study as intermediates for Vitamin A synthesis are described. The utility of commercially available materials namely 2-acetylbutyrolactone and levulinic acid in -the preparation of C5 intermediates for Vitamin A synthesis is demonstrated. |
| Description: | Department Of Applied Chemistry Cochin University Of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3495 |
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| Dyuthi-T1431.pdf | (1.607Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1020 |
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| Jose David P 1989.pdf | (233.8Kb) |
| Abstract: | 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 |
| Description: | School of Marine Science, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3185 |
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| Dyuthi-T1159.pdf | (23.56Mb) |
| Abstract: | Rainbow sardines of the genus belonging to the family Dueenaieriidae. are small pelagic fishes forming a fairly good, though not abundant. seasonal fishery all along the coasts of India inhabiting the coastal waters. There have been some earlier reports on such individual aspects as their systematic, distribution, abundance. Ostecology and a few biological factors but no attempt has been made towards a comprehensive study on this group. Two species of rainbow sardines are known to occur in the Indian seas and while a knowledge about their biology would be useful from the fishery point of view. it was also thought a study of their systematic position, especially regarding the identity or the two species which had raised doubts among earlier workers would lead to a better understanding or the group as a whole. This thesis is mainly based on studies during the period from April 1969 to march 1971 with a continued investigation of fishhery aspects till December 1975. from the Gulf of manar: and the Palk Bay around mandapam area. on the south-east coast of India. Thus the work deals with the systemtics, biology and fishery of rainbow sardines of Indian seas. |
| Description: | Central Marine Fisheries Research Institute |
| URI: | http://dyuthi.cusat.ac.in/purl/3403 |
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| Dyuthi-T1380.pdf | (10.66Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1160 |
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| Radhakrishnan Nair P N 1984.PDF | (219.3Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1153 |
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| Madhusoodana Kurup B 1983.PDF | (286.0Kb) |
| Abstract: | The oceans in their expanse cover, seven - tenths of the Earth surface. Despite being restricted in size, the littoral zone or the intertidal zone (beach) has the greatest variation in environment factors of any marine area .Stemming from this variation ,a treamendous diversity of life, which may be great as or greater than that found in the more extensive sub tidal habits exist in this realm. the study beaches harbour diverse and abundant assemblage of marine organisms. Besides macro funna, microscopic organisms belonging to the lower and higher invertebrate taxa profusely inhabit these beaches. The ecological realm where these animals exist is known as the interstitial environment, which in principle includes the pore spaces in between the sand grains containing copious supply of nutrient rich oxygenated seawater. An astonishing diversity of taxa could be found within the interstitial fauna. |
| URI: | http://dyuthi.cusat.ac.in/purl/3022 |
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| Dyuthi-T1000.pdf | (37.30Mb) |
| Abstract: | Trawling, despite being heavily energy expensive, still continues to be the most energy expensive fishing method particularly so in View of the export oriented nature of the Indian seafood industry. This study therefore aims at analyzing the efficiency of trawls operation from Cochin, an important fishing center along the southwest coast of India. The analysis is made along two perspectives - economic and technological. Even though technological efficiency complement economic efficiency, in the fishing parlance, parameters like the size composition of the catch, selectivity factors, etc., will have a direct bearing on the technological qualities of the trawl, and which parameters will have a significant impact on the effective exploitation of a fishery stock. Whereas the technological analysis aims at improving the efficiency with regard to the effective utilization of fuel and fishery stocks, economic analysis ascertains the present status of the trawling operations from the commercial angle. |
| Description: | Department of Industrial Fisheries,School of Marine Science, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3207 |
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| Dyuthi-T1181.pdf | (4.609Mb) |
| Abstract: | Teredinids (shipworms), a group of wood boring bivalves occurring in the Cochin Harbour region have been taken up for the eco-physiological studies. On the ecological part, the occurrence, abunance and seasonal intensity of the teredinids in relation to hydrographic conditions have been studied. On the physiological part, salinity tolerance and oxygen consumption of the most commonly occurring shipworms, Nausitcra hedlgyi and Teredo furcifera have been investigated. The hydrographic factors studied are temperature, salinity, dissolved oxygen, phosphate, nitrite, silicate and pH. The variation in temperature is found to be comparatively narrow. But seasonal variation in salinity, dissolved oxygen, phosphate, nitrite and silicate has been observed, with the highest values during the monsoon period. In the case of pH, the minimum value has been obtained during the low saline period and the maximum value, during the high saline period. Of the various hydrographic factors studied, salinity has been found to be the most important fluctuating environmental parameter influencing the life of organisms in the habitat. |
| Description: | School of marine sciences, Cochin University of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3292 |
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| Dyuthi-T1274.pdf | (7.152Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1842 |
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| Dyuthi-T0263.pdf | (4.978Mb) |
| Abstract: | This thesis aims to develop new toughened systems for epoxy resin via physical and chemical modifications. Initially the synthesis of DGEBA was carried out and the properties compared with that of the commercial sample. Subsequently the modifier resins to be employed were synthesized. The synthesized resin were characterized by spectroscopic method (FTIR and H NMR), epoxide equivalent and gel permeation chromatography. Chemical modification involves the incorporation of thermoset resins such a phenolics, epoxy novolacs, cardanol epoxides and unsaturated polyester into the epoxy resin by reactive belnding. The mechanical and thermal properties of the blends were studied. In the physical modification route, elastomers, maleated elastomers and functional elastomers were dispersed as micro-sized rubber phase into the continuous epoxy phase by a solution blending technique as against the conventional mechanical blending technique. The effect of matrix toughening on the properties of glass reinforced composites and the effect of fillers on the properties of commercial epoxy resin were also investigated. The blends were characterized by thermo gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy and mechanical property measurements. Among the thermoset blends, substantial toughening was observed in the case of epoxy phenolic novolacs especially epoxy para cresol novolac (ECN). In the case of elastomer blending , the toughest blends were obtained in the case of maleic anhydride grafted NBR. Among functional elastomers the best results were obtained with CTBN. Studies on filled and glass reinforced composites employing modified epoxy as matrix revealed an overall improvement in mechanical properties |
| URI: | http://dyuthi.cusat.ac.in/purl/759 |
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| Dyuthi-T0257.pdf | (5.992Mb) |
| Abstract: | Industrialisation affects air, water, and soil. Industrial effluents which enter the aquatic environment either by direct disposal or through run off, affect living organisms at morphological and physiological levels. In any living tissue toxic materials exert their effects first at molecular and biochemical levels (Robbins and Angell, 1976). Most of the industrial effluents contain elevated concentrations of organic and inorganic chemicals capable of eliciting stimulatory or inhibitory effects on the metabolism of aquatic organisms. Heavy metals form an important group of environmental pollutants. Effects of pollution on the aquatic environment by heavy metals have received considerable attention in recent years due to their toxicity even at very low levels, persistence in the environment, and chances of getting biomagnified. A pollutant that does not affect a particular process under normal unstressed condition may affect the ability of the animal to adjust to changing environmental conditions which ultimately decrease its chances of survival (Thurberg et al., 1973 |
| Description: | School of Environmental Studies, Cochin University of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3737 |
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| Dyuthi-T1691.pdf | (3.191Mb) |
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