| Abstract: | Soil erosion is more detrimental and affects the chemical, physical and biological properties of the soil. Degradation of soil and water resources is a worldwide problem. Over the next two decades, it is expected that the world will need 17% more water to grow food for the increasing population in developing countries and that total water use will increase by 40%. The total land area subjected to human-induced soil degradation is estimated as 20 x 106 (km)2 Hence conservation of soil and water is essential for the subsistence of life. This can be made possible through sustainable watershed management. This thesis aims at investigating the condition under which sustainable watershed management is possible in Kerala, in South India. The research has been carried out in three stages. In the first stage a conceptual framework is formulated (Chapter 3) based on the relevant literature (Chapter 2) in the field of watershed management. In the second stage this framework is applied to two existing case studies in Kerala State (Chapter 4). In the third stage, the methodology is used to test out geo textile innovation (Chapter 5) in two field experiments (Chapter 6). |
| Description: | Department of environmental studies, Cochin University of Science And Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3418 |
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| Dyuthi-T1313.pdf | (9.114Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5585 |
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| Dyuthi T-2626.pdf | (12.50Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5124 |
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| Dyuthi-T 2189.pdf | (1.899Mb) |
| Abstract: | hindi |
| Description: | Department of Hindi, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4751 |
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| Dyuthi-T1848.pdf | (6.274Mb) |
| Abstract: | Hindi |
| Description: | Department of Hindi,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4761 |
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| Dyuthi-T1858.pdf | (4.914Mb) |
| Abstract: | HINDI |
| Description: | Department off Hindi, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4819 |
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| Dyuthi-T1916.pdf | (4.732Mb) |
| Abstract: | hindi |
| Description: | Department of Hindi, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4759 |
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| Dyuthi-T1856.pdf | (3.694Mb) |
| Description: | Department of Hindi, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3002 |
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| Dyuthi-T0982.pdf | (1.039Mb) |
| Abstract: | Natural rubber/isora fibre composites were cured at various temperatures. The solvent swelling characteristics of natural rubber composites containing both untreated and alkali treated fibres were investigated in aromatic and aliphatic solvents like toluene, and n-hexane. The diffusion experiments were conducted by the sorption gravimetric method. The restrictions on elastomer swelling exerted by isora fibre as well as the anisotropy of swelling of the composite have been confirmed by this study. Composite cured at 100°C shows the lowest percentage swelling. The uptake of aromatic solvent is higher than that of aliphatic solvent for the composites cured at all temperatures. The effect of fibre loading on the swelling behaviour of the composite was also investigated in oils like petrol, diesel, lubricating oil etc. The % swelling index and swelling coefficient of the composite were found to decrease with increase in fibre loading. This is due to the increased hindrance exerted by the fibres at higher fibre loadings and also due to the good fibre-rubber interactions. Maximum uptake of solvent was observed with petrol followed by diesel and then lubricating oil. The presence of bonding agent in the composites restrict the swelling considerably due to the strong interfacial adhesion. At a fixed fibre loading, the alkali treated fibre composite showed lower percentage swelling compared to the untreated one. |
| URI: | http://dyuthi.cusat.ac.in/purl/807 |
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| Lovely Mathew a ... g behavior..,Sept.2005.PDF | (6.644Mb) |
| Abstract: | Swift heavy ion induced changes in microstructure and surface morphology of vapor deposited Fe–Ni based metallic glass thin films have been investigated by using atomic force microscopy, X-ray diffraction and transmission electron microscopy. Ion beam irradiation was carried out at room temperature with 103 MeV Au9+ beam with fluences ranging from 3 1011 to 3 1013 ions/cm2. The atomic force microscopy images were subjected to power spectral density analysis and roughness analysis using an image analysis software. Clusters were found in the image of as-deposited samples, which indicates that the film growth is dominated by the island growth mode. As-deposited films were amorphous as evidenced from X-ray diffraction; however, high resolution transmission electron microscopy measurements revealed a short range atomic order in the samples with crystallites of size around 3 nm embedded in an amorphous matrix. X-ray diffraction pattern of the as-deposited films after irradiation does not show any appreciable changes, indicating that the passage of swift heavy ions stabilizes the short range atomic ordering, or even creates further amorphization. The crystallinity of the as-deposited Fe–Ni based films was improved by thermal annealing, and diffraction results indicated that ion beam irradiation on annealed samples results in grain fragmentation. On bombarding annealed films, the surface roughness of the films decreased initially, then, at higher fluences it increased. The observed change in surface morphology of the irradiated films is attributed to the interplay between ion induced sputtering, volume diffusion and surface diffusion |
| Description: | Nuclear Instruments and Methods in Physics Research B 287 (2012) 85–90 |
| URI: | http://dyuthi.cusat.ac.in/purl/4407 |
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| Swift heavy ion ... tion in metallic glass.pdf | (1.092Mb) |
| Abstract: | Fe–Ni based amorphous thin films were prepared by thermal evaporation. These films were irradiated by 108 MeV Ag8+ ions at room temperature with fluences ranging from 1 1012 to 3 1013 ions/cm2 using a 15 UD Pelletron accelerator. Glancing angle x-ray diffraction studies showed that the irradiated films retain their amorphous nature. The topographical evolution of the films under swift heavy ion SHI bombardment was probed using atomic force microscope and it was noticed that surface roughening was taking place with ion beam irradiation. Magnetic measurements using a vibrating sample magnetometer showed that the coercivity of the films increases with an increase in the ion fluence. The observed coercivity changes are correlated with topographical evolution of the films under SHI irradiation. The ability to modify the magnetic properties via SHI irradiation could be utilized for applications in thin film magnetism |
| Description: | J. Appl. Phys. 105, 033910 2009 |
| URI: | http://dyuthi.cusat.ac.in/purl/4377 |
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| Swift heavy ion ... d amorphous thin films.pdf | (674.4Kb) |
| Abstract: | Magnetism and magnetic materials have been playing a lead role in the day to day life of human beings. The human kind owes its gratitude to the ‘lodestone’ meaning ‘leading stone’ which lead to the discovery of nations and the onset of modern civilizations. If it was William Gilbert, who first stated that ‘earth was a giant magnet’, then it was the turn of Faraday who correlated electricity and magnetism. Magnetic materials find innumerable applications in the form of inductors, read and write heads, motors, storage devices, magnetic resonance imaging and fusion reactors. Now the industry of magnetic materials has almost surpassed the semiconductor industry and this speaks volumes about its importance. Extensive research is being carried out by scientists and engineers to remove obsolescence and invent new devices. Though magnetism can be categorized based on the response of an applied magnetic field in to diamagnetic, paramagnetic, ferromagnetic, ferrimagnetic and antiferromagnetic; it is ferrimagnetic, ferromagnetic and antiferromagnetic materials which have potential applications. The present thesis focusses on these materials, their composite structures and different ways and means to modify their properties for useful applications. |
| URI: | http://dyuthi.cusat.ac.in/purl/5069 |
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| Dyuthi-T 3133.pdf | (6.109Mb) |
| Abstract: | Magnetism and magnetic materials have been playing a lead role in the day to day life of human beings. The human kind owes its gratitude to the ‘lodestone’ meaning ‘leading stone’ which lead to the discovery of nations and the onset of modern civilizations. If it was William Gilbert, who first stated that ‘earth was a giant magnet’, then it was the turn of Faraday who correlated electricity and magnetism. Magnetic materials find innumerable applications in the form of inductors, read and write heads, motors, storage devices, magnetic resonance imaging and fusion reactors. Now the industry of magnetic materials has almost surpassed the semiconductor industry and this speaks volumes about its importance. Extensive research is being carried out by scientists and engineers to remove obsolescence and invent new devices. Though magnetism can be categorized based on the response of an applied magnetic field in to diamagnetic, paramagnetic, ferromagnetic, ferrimagnetic and antiferromagnetic; it is ferrimagnetic, ferromagnetic and antiferromagnetic materials which have potential applications. The present thesis focusses on these materials, their composite structures and different ways and means to modify their properties for useful applications. In the past, metals like Fe, Ni and Co were sought after for various applications though iron was in the forefront because of its cost effectiveness and abundance. Later, alloys based on Fe and Ni were increasingly employed. They were used in magnetic heads and in inductors. Ferrites entered the arena and subsequently most of the newer applications were based on ferrites, a ferrimagnetic material, whose composition can be tuned to tailor the magnetic properties. In the late 1950s a new class of magnetic material emerged on the magnetic horizon and they were fondly known as metallic glasses. They are well known for their soft magnetic properties. They were synthesized in the form of melt spun ribbons and are amorphous in nature and they are projected to replace the crystalline counterparts. |
| URI: | http://dyuthi.cusat.ac.in/purl/5067 |
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| Dyuthi-T 2130.pdf | (6.114Mb) |
| Abstract: | Pyridoxal phosphate is the coenzyme of various decarboxylases involved in the formation of monoamine neurotransmitters such as y-aminobutyric acid , serotonin , dopamine, and norepinephrine . Adult male Sprague-Dawley rats placed on a pyridoxine -deficient diet for 8 weeks showed significant hypertension compared with pyridoxine -supplemented controls . Hypothalamic contents of pyridoxal phosphate , y-aminobutyric acid, and serotonin in the pyridoxine - deficient rats were significantly lower than those in pyridoxine -supplemented controls . Hypertension was associated with sympathetic stimulation . Treatment of pyridoxine-deficient rats with a single dose of pyridoxine (10 mg/kg body weight) reversed the blood pressure to normal levels within 24 hours, with concomitant restorations of hypothalamic serotonin and y-aminobutyric acid as well as the return of plasma norepinephrine and epinephrine to normal levels . Also, pyridoxine treatment reversed the hypothalamic hypothyroidism observed in pyridoxine -deficient rats . These results indicate an association between pyridoxine deficiency and sympathetic stimulation leading to hypertension. |
| URI: | http://dyuthi.cusat.ac.in/purl/651 |
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| C S Paulose and others(1987)dec.8.PDF | (4.659Mb) |
| Abstract: | In this Letter we numerically investigate the dynamics of a system of two coupled chaotic multimode Nd:YAG lasers with two mode and three mode outputs. Unidirectional and bidirectional coupling schemes are adopted; intensity time series plots, phase space plots and synchronization plots are used for studying the dynamics. Quality of synchronization is measured using correlation index plots. It is found that for laser with two mode output bidirectional direct coupling scheme is found to be effective in achieving complete synchronization, control of chaos and amplification in output intensity. For laser with three mode output, bidirectional difference coupling scheme gives much better chaotic synchronization as compared to unidirectional difference coupling but at the cost of higher coupling strength. We also conclude that the coupling scheme and system properties play an important role in determining the type of synchronization exhibited by the system. |
| URI: | http://dyuthi.cusat.ac.in/purl/2530 |
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| Dyuthi-P0105.pdf | (451.1Kb) |
| Abstract: | Synechocystis MCCB 114 and 115 were segregated as putative probionts for shrimp larvae from a collection of 54 cyanobacterial cultures enriched from seawater. On feeding Penaeus monodon post-larvae with the cyanobacteria, the generic diversity of the intestinal bacterial flora could be enhanced with substantial reduction or total absence of Vibrio spp. A significant difference (p < 0.001) in the percent survival of batches of post-larvae fed on the cyanobacterial cultures was observed and, on repeated challenge with V. harveyi, the relative percent survival of those batches of larvae fed on Synechocystis MCCB 114 and 115 was significantly higher. The Synechocystis MCCB 114 and 115 cultures were found to contain high levels of protein (34 to 43%), in addition to carotenoids |
| Description: | Dis Aquat Org 74: 243–247, 2007 |
| URI: | http://dyuthi.cusat.ac.in/purl/4052 |
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| Synechocystis M ... us monodon post-larvae.pdf | (62.53Kb) |
| Abstract: | The research work which was carried out to Synergic Reactions in the Estuarine Environment leading to Modulation of Aluminium metal during Transport Processes (in Cochin Estuary)Estuaries are considered as sink or source for terrestrial and various anthropogenically generated materials. These include naturally occurring elements Al, Si, Fe or trace inorganics or industrial pollutants of different types. There have been reports on both positive and negative impacts by the introduction of above materials into the ecosystem.This thesis deals with the trace metal Aluminium (Al) whose average concentration (about 8%) in the earths crust is surpassed only by that of Oxygen and Silicon. There can be no doubt that most of the land derived materials reaches the ocean through rivers via estuaries. An important aspect noticed here is that the concentration of dissolved Al is much lower in sea water than in river water.On critically analysing Cochin estuary, for the entire cycles, covering monsoon, postmonsoon and premonsoon, the following salient features are documented as hereunder. Dissolved Al exhibits high and variable trends in Cochin estuary, the influencing parameters being salinity, SPM, pH and dissolved Si. A general profile showed removal in upper/mid estuary followed by regeneration in the mid/lower estuary and further decrease seawards in the southern/northem arms.Distribution appears to be a function of freshwater input, the monsoon season exhibiting very high concentrations throughout the estuary. As the river discharge decreased with the progress of seasons, dissolved Al concentration also decreased, the metal limiting itself to the upper and mid estuary. |
| Description: | Department of Physical Oceanography,School of Marine Science, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3113 |
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| Dyuthi-T1087.pdf | (4.312Mb) |
| Abstract: | Zinc salts of ethyl, isopropyl and butyl xanthates were prepared in the laboratory. The effect of these xanthates with zinc diethyldithiocarbamate (ZDC) on the vulcanization of HAF filled NR compound has been studied at different temperatures. The rubber compounds with the three xanthate accelerators and ZDC were cured at various temperatures from 60°C to 150°C. The sheets were moulded and properties such as tensile strength , tear strength , cross-link density, elongation -at-break, compression set, heat build up, abrasion resistance, flex resistance , etc. were evaluated . The properties showed that zinc xanthate/ZDC accelerator combination has a positive synergistic effect on the mechanical properties of NR compounds. The curing of HAF filled NR compound containing zinc xanthate /ZDC is slightly slower than the curing of the corresponding gum compounds . It is observed that, by gradually increasing the amount of the accelerator, the cure time of black filled NR compound can be made equal to that of the gum compou |
| URI: | http://dyuthi.cusat.ac.in/purl/814 |
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| Shiny Palaty an ... nergism of...,July2003.PDF | (5.107Mb) |
| Abstract: | The thesis entitled “Synergistic solvent extraction of Thorium(IV) and Uranium(VI) with β-diketones in presence of oxo-donors” embodies the results of the investigations carried out on the extraction of thorium(IV) an uranium(VI) with heterocyclic β-diketones in the presence and absence of various macrocyclic ligands and neutral organophosphorus extractants. The objective of this work is to generate the knowledge base to achieve better selectivity between thorium(IV) and uranium(VI) by understanding the interactions of crown ethers or neutral organophosphorus extractants with metal-heterocyclic β-diketonate complexes. Para-substituted 1-phenyl-3-methyl-4-aroyl-5-pyrazolones, namely,1-phenyl-3-methyl-4-(4-fluorobenzoyl)-5-pyrazolone (HPMFBP) and 1-phenyl-3-methyl-4-(4-toluoyl)-5-pyrazolone (HPMTP) were synthesized and characterized by elemental analysis, IR and H NMR spectral data. The synthesized ligands have been utilized for the extraction of thorium(IV) and uranium(VI) from nitric acid solutions in the presence and absence of various crown ethers. Thorium(IV) and uranium(VI) complexes with HPMPP(1-Phenyl-3-methyl-4-pivaloyl-5-pyrazolone) and neutral organophosphorus extractants were synthesized and characterized by IR and P NMR spectral data to further understand the interactions of neutral organophosphorus extractants with metal-chelates. Solid complexes of thorium(IV) and uranium(VI) with para-substituted 4-aroyl-5-isoxazolones and crown ethers were isolated and characterized by various spectroscopic techniques to further clarify the nature of the extracted complexes. |
| URI: | http://dyuthi.cusat.ac.in/purl/912 |
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| Dyuthi-T0294.pdf | (2.603Mb) |
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