| Abstract: | Cryptosystem using linear codes was developed in 1978 by Mc-Eliece. Later in 1985 Niederreiter and others developed a modified version of cryptosystem using concepts of linear codes. But these systems were not used frequently because of its larger key size. In this study we were designing a cryptosystem using the concepts of algebraic geometric codes with smaller key size. Error detection and correction can be done efficiently by simple decoding methods using the cryptosystem developed. Approach: Algebraic geometric codes are codes, generated using curves. The cryptosystem use basic concepts of elliptic curves cryptography and generator matrix. Decrypted information takes the form of a repetition code. Due to this complexity of decoding procedure is reduced. Error detection and correction can be carried out efficiently by solving a simple system of linear equations, there by imposing the concepts of security along with error detection and correction. Results: Implementation of the algorithm is done on MATLAB and comparative analysis is also done on various parameters of the system. Attacks are common to all cryptosystems. But by securely choosing curve, field and representation of elements in field, we can overcome the attacks and a stable system can be generated. Conclusion: The algorithm defined here protects the information from an intruder and also from the error in communication channel by efficient error correction methods. |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2007 |
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| A Cryptosystem using....pdf | (93.25Kb) |
| Abstract: | The current scenario of coordination chemistry is witnessing the exploitation of coordination bonds and noncovalent interactions to generate self-assemblies of various dimensions having not only aesthetic values but also countless applications and that paved way for supramolecular chemistry/crystal engineering. Most of such fascinating work employs Schiff bases obtained by the condenzation of an amine and a carbonyl compound. The use of diamines in the synthesis of highnuclearity complexes utilizes the bridging capacity of phenoxo atoms. Whereas in the case of N2O donor tridentate Schiff bases (N-substituted diamines with salicylaldehyde or its derivatives), coligands are employed to generate structures of variable composition apart from satisfying the coordination number. Among the various coligands known, pseudohalides (azido, cyanato, thiocyanato, dicyanamido) deserve special attention on account of its versatile modes of binding. In addition to the structural variety, such Schiff base complexes have its signature in the field of catalysis, luminescence, gas adsorption and magnetic materials which make the arena conspicuous. The recognition of plasticity of copper(II) metal with respect to its coordination number and its ubiquitous nature as active sites in many metalloenzymes fuelled us to work with this metal. The results of our efforts to explore the role of various interaction forces constitute the subject matter of the thesis entitled “Crystalline architectures of copper(II) complexes derived from halogen substituted carbonyl compounds: Interplay of covalent and non-covalent forces”. The work embodied in this thesis was carried out by the author in the Department of Applied Chemistry, CUSAT, Kochi, during the period 2011-2016 and is divided into eight chapters. |
| URI: | http://dyuthi.cusat.ac.in/purl/5137 |
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| Dyuthi-T2171.pdf | (24.08Mb) |
| Abstract: | Thiosemicarbazones have emerged as an important class of ligands over a period of time, for a variety of reasons, such as variable donor properties, structural diversity and biological applications. Interesting as the coordination chemistry may be, the driving force for the study of these ligands has undoubtedly been their biological properties and the majority of the 3000 or so publications on thiosemicarbazones since 2000 have alluded to this feature. Thiosemicarbazones with potential donor atoms in their structural skeleton fascinate coordination chemists with their versatile chelating behavior. The thiosemicarbazones of aromatic aldehydes and ketones form stable chelates with transition metal cations by utilizing both their sulfur and azomethine nitrogen as donor atoms. They have been shown to possess a diverse range of biological activities including anticancer, antitumor, antibacterial, antiviral, antimalarial and antifungal properties owing to their ability to diffuse through the semipermeable membrane of the cell lines. The enhanced effect may be attributed to the increased lipophilicity of the metal complexes compared to the ligand alone. |
| Description: | Department of Applied Chemistry, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3747 |
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| Dyuthi-T1709.pdf | (5.286Mb) |
| Abstract: | Supra molecular architectures of coordination complexes of liydrazones through non covalent interactions have been explored. Molecular self—assernbly driven by weak interactions such as hydrogen— bonding, K '”T[, C-1-I‘ "TE, van der Waals interactions, and so forth are currently of tremendous research interest in the fields of molecule based materials. The directional properties of the hydrogembonding interaction associate discrete molecules into aggregate structures that are sufficiently stable to be considered as independent chemical species. Chemistry can borrow nature’s strategy to utilize hydrogen-bonding as Well as other noncovalent interactions as found in secondary and tertiary structures of proteins such as the double helix folding of DNA, hydrophobic selflorganization of phospholipids in cell membrane etc. In supramolecular chemistry hydrogen bonding plays an important role in forming a variety of architectures. Thus, the wise modulation and tuning of the complementary sites responsible for hydrogen—bond formation have led to its application in supramolecular electronics, host-guest chemistry, self-assembly of molecular capsules, nanotubes etc. The work presented in this thesis describes the synthesis and characterization of metal complexes derived from some substituted aroylhydrazones. The thesis is divided into seven chapters. |
| Description: | Department of Applied Chemistry, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3491 |
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| Dyuthi-T1430.pdf | (3.011Mb) |
| Abstract: | A new electronically reconfigurable dual frequency microstrip patch antenna with highly simplified varactor tuning circuitry is presented. The proposed design allows relatively independent selection of the two operating frequencies. Tuning ranges of 7.1 and 4.1% are realised for the two resonant frequencies without the use of any matching circuits. |
| URI: | http://dyuthi.cusat.ac.in/purl/2758 |
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| Dyuthi-P00377.pdf | (94.62Kb) |
| Abstract: | Thin film solar cells having structure CuInS2/In2S3 were fabricated using chemical spray pyrolysis (CSP) technique over ITO coated glass. Top electrode was silver film (area 0.05 cm2). Cu/In ratio and S/Cu in the precursor solution for CuInS2 were fixed as 1.2 and 5 respectively. In/S ratio in the precursor solution for In2S3 was fixed as 1.2/8. An efficiency of 0.6% (fill factor -37.6%) was obtained. Cu diffusion to the In2S3 layer, which deteriorates junction properties, is inevitable in CuInS2/In2S3 cell. So to decrease this effect and to ensure a Cu-free In2S3 layer at the top of the cell, Cu/In ratio was reduced to 1. Then a remarkable increase in short circuit current density was occurred from 3 mA/cm2 to 14.8 mA/cm2 and an efficiency of 2.13% was achieved. Also when In/S ratio was altered to 1.2/12, the short circuit current density increased to 17.8 mA/cm2 with an improved fill factor of 32% and efficiency remaining as 2%. Thus Cu/In and In/S ratios in the precursor solutions play a crucial role in determining the cell parameters |
| Description: | Energy Procedia 15 ( 2012 ) 283 – 290 |
| URI: | http://dyuthi.cusat.ac.in/purl/4722 |
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| CuInS2In2S3 Cel ... ios on Cell Parameters.pdf | (1.060Mb) |
| Description: | Dept.of Physics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2113 |
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| Dyuthi-T0386.pdf | (7.080Mb) |
| Abstract: | Hindi |
| Description: | Department of Hindi, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4828 |
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| Dyuthi-T1925.pdf | (6.728Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1164 |
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| Ammini Joseph 1984.PDF | (271.8Kb) |
| Abstract: | The present study on naoplankton is based on the isolation and development of unialgai culturas from the inshore waters at Cochin. characterization of their growth assimilation products. ecophysioiogy and evaluation of nutritional quality. The work was carried out during the period 1980-1983. The nanoplankters were isolated and grown in the labratory as batch cultures to study the increase in cell population, the photosynthetic pigment: ana physioiogical activity. The chemical composition of these organisms and their rate of excretion were also determined. The environmental factors physical and chemical that influence the growth of these Cultures were defined by conducting independentexperiments. These cultures of the isolated nanoplankters have raised indoor and fed to the larvae of edible oyster to test their suitability as live-food. |
| Description: | Central Marine Fisheries Research Institute |
| URI: | http://dyuthi.cusat.ac.in/purl/3551 |
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| Dyuthi-T1519.pdf | (17.80Mb) |
| Abstract: | The present study is an attempt to standardize the environmental condition like pH, salinity and photoperiod, and also the feed for the maximum production of rotifers. Considering the deficiency of essential fatty acids in rotifers, enrichment experiments were carried out and fatty acids profile were analysed. Attempts were made to improve the production of clown fish (Amphiprion sebae) juveniles using enriched rotifers. Attempts were also made to rear various larval stages of Penaeus monodon with enriched rotifers as a substitute for Artemia nauplii. |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2083 |
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| Dyuthi-T0387.pdf | (5.523Mb) |
| Abstract: | Earlier studies on measurement of customer satisfaction are based on either transaction specific or overall approaches. The transaction specific approach evaluates customer satisfaction with single components in the whole purchase process but the overall satisfaction was based on all the encounters or experiences to the customer throughout the purchase process. Consumers will comment on particular events of their purchase process when asked about transaction-specific satisfaction and they will comment their overall impression and general experiences in overall satisfaction (Bitner & Hubbert 1994) Through a critical review on the literature, it has been identified a new approaches to customer satisfaction, say, cumulative approaches that can be more useful than overall and transaction specific approaches for strategic decision making (Fornell et al 1996). The cumulative approach to customer satisfaction doesn’t study earlier due to the difficulty in operationalization of the concept. But the influencers of customer satisfaction are context specific and the prevailing models doesn’t give the sources of variations in the satisfaction, the importance of cumulative approaches to customer satisfaction has emerges that lights to a new research. The current study has focused to explore the influencers of overall customer satisfaction to form individual elements that can be used to identify the cumulative customer satisfaction. |
| URI: | http://dyuthi.cusat.ac.in/purl/4935 |
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| Dyuthi _T2010.pdf | (3.580Mb) |
| Abstract: | The scope of the work was to synthesis few biologically active derivatives of curcumin. The derivatives were prepared by altering the keto-enol centre of curcumin by various reagents. This particular reaction centre for preparing derivative was selected keeping in mind the controversy regarding the major site responsible for antioxidant mechanism of curcumin. Most of the mechanistic study done earlier was by varying the constituents in one or both of the phenol ring present in the curcumin. The alterations at the keto-enol moiety may throw an insight into the role of the diketo moiety towards the antioxidant mechanism. Since recently curcumin has been suggested as a chemotherapeutic agent for various ailments, we also decided to check the DNA intercalating property of the derivatives synthesised. |
| Description: | Department of Applied Chemistry Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3754 |
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| Dyuthi-T1716.pdf | (7.046Mb) |
| Abstract: | Blends of styrene butadiene rubber (SBR) with maleic anhydride grafted whole tire reclaim (MA-g-WTR) have been prepared and the cure and mechanical properties have been studied with respect to the reclaim content. The grafting was carried out in the presence of dicumylperoxide (DCP) in a Brabender Plasticorder at 150'C. The presence of anhydride group on the WTR was confirmed by infrared spectrometry (IR) study. The properties were compared with those of the blends containing unmodified WTR. Though the cure time was marginally higher, the mechanical properties of the blends containing grafted WTR were better than that of the unmodified blends. |
| URI: | http://dyuthi.cusat.ac.in/purl/886 |
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| NELSON P A, S. ... aracteristics and......PDF | (5.257Mb) |
| Abstract: | Ultra fine nickel ferrite have been synthesized by the sol-gel method. By heat treating different portions of the prepared powder separately at different temperatures, nano-sized particles of nickel ferrite with varying particle sizes were obtained. These powders were characterised by the X-ray diffraction and then incorporated in the nitrile rubber matrix according to a specific recipe for various loadings. The cure characteristics and the mechanical properties of these rubber ferrite composites (RFCs) were evaluated. The effect of loading and the grain size of the filler on the cure characteristics and tensile properties were also evaluated. It is found that the grain size and porosity of the filler plays a vital role in determining the mechanical properties of the RFCs |
| Description: | Journal ofAppliedPolymer Science,Vol. 119, 3019–3025 (2011) |
| URI: | http://dyuthi.cusat.ac.in/purl/4424 |
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| Cure Characteri ... n Nano-Nickel Ferrites.pdf | (692.2Kb) |
| Abstract: | Cure characteristics and mechanical properties of short nylon fiber reinforced acrylonitrile butadiene rubber-reclaimed rubber composites were studied. Minimum torque, (maximum-minimum) torque and cure rate increased with fiber concentration. Scorch time and cure time decreased by the addition of fibers. Properties like tensile strength, tear strength, elongation at break, abrasion loss and heat build up were studied in both orientations of fibers. Tensile and tear properties were enhanced by the addition of fibers and were higher in the longitudinal direction. Heat build up increased with fiber concentration and were higher in the longitudinal direction. Abrasion resistance was improved in presence of short fibers and was higher in the longitudinal direction. Resilience increased on the introduction of fibers. Compression set was higher for blends. |
| URI: | http://dyuthi.cusat.ac.in/purl/897 |
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| sreeja T D, S. ... teristics and .........PDF | (4.832Mb) |
| Abstract: | Cure characteristics of short polyester fiber-polyurethane composites with respect to different bonding agents (MD resins) based on 4, 4' diphenylmethanediisocyanate (MDI) and various diols like propyleneglycol (PG), polypropyleneglycol (PPG) and glycerol (GL) were studied. Tmax. - Tmin. of composites having MD resin were found to be higher than the composite without MD resin. Minimum torque and Tmax. - Tmin., scorch time and optimum cure time were increased with the increase of MDI equivalence. Optimum ratio of MDI / -of in the resin was found to be within the range of 1-1.5. It was observed from the cure characteristics that for getting better adhesion between short polyester fiber and the polyurethane matrix the best choice of MD resin was one based on MDI and 1:1 equivalent mixture of polypropyleneglycol and glycerol. |
| URI: | http://dyuthi.cusat.ac.in/purl/902 |
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| Suhara, F S K N ... polyester..............PDF | (7.438Mb) |
| Abstract: | Rubber ferrite composites were prepared by incorporating nickel ferrite in a neoprene rubber matrix. Kinetics of the cure reaction were determined from the rheometric torque values and found to follow first-order kinetics. Analysis of the swelling behavior of the rubber ferrite composites in toluene elucidates the mechanism of solvent penetration and sorption characteristics, and reveals the extent of the physical interaction of the ferrite particles with the neoprene rubber matrix. Mechanical properties of rubber ferrite composites were determined, which support the reinforcing nature of nickel ferrite to the neoprene rubber matrix. These results show that magnetic composites with the required processing safety can be prepared economically by incorporating higher amounts of nickel ferrite in the neoprene rubber matrix |
| Description: | International Journal of Polymeric Materials, 59:173–183, 2010 |
| URI: | http://dyuthi.cusat.ac.in/purl/4425 |
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| Cure Kinetics a ... ber Ferrite Composites.pdf | (327.4Kb) |
| Abstract: | There are a large number of commercial examples and property advantages of immiscible elastomer blends.73 Blends of natural rubber (NR) and polybutadiene (BR) have shown various advantages including heat stability, improved elasticity and abrasion resistance. Ethylene-propylene-diene-rubber (EPDM) blended with styrene-butadiene rubber (SBR) has shown improvements in ozone and chemical resistance with better compression set properties. Blends of EPDM and nitrile rubber (NBR) have been cited as a compromise for obtaining moderate oil and ozone resistance with improved low temperature properties. Neoprene (CR)/BR blends offer improved low temperature properties and abrasion resistance with better processing characteristics etc. However, in many of the commercial two-phase elastomer blends, segregation of the crosslinking agents, carbon black or antioxidants preferentially into one phase can result in failure to attain optimum properties. Soluble and insoluble compounding ingredients are found to be preferentially concentrated in one phase. The balance of optimum curing of both phases therefore presents a difficult problem. It has been the aim of this study to improve the performance of commercially important elastomer blends such as natural rubber (NR)/styrene-butadiene rubber (SBR) and natural rubber/polybutadiene rubber (BR) by industrially viable procedures |
| Description: | Department Of Polymer Science And Rubber technology |
| URI: | http://dyuthi.cusat.ac.in/purl/3288 |
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| Dyuthi-T1263.pdf | (9.825Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/1308 |
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| Rani Joseph 1988.PDF | (157.1Kb) |
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