| Abstract: | In many fields such as earth science biology, environment and electronics, the knowledge about elemental distributions and chemical speciation is important. The determination of metal levels especially the toxic ones both in the environment and in biological materials are increasingly demanded by the society.Ion selective sensors have become one of the most effective ad powerful means for analytical scientists for the trace level monitoring of metal ions. The wide range of applications ,low material requirements and simplicity of analytical procedure have not only brought ion-selective electrodes in to the lime light of analytical chemistry,but have promoted their use as tools for physiologists,medical researchers,biologists,geologists,environmental protection specialists etc.Potentiometric ion-selective sensors have been developed for the determination of lanthanide ions such as La3+,Nd3+,Pr3+,Sm3+, and Gd3+.The sensors fabricated include both PVC membrane sensor and chemically modified carbon paste sensor. A set of 10 sensors have been developed. The response parameters of all the sensors have been studied and the sensors were applied as an indicator electrode in the potentiometric titration and for the determination of metal ions in real samples. |
| Description: | Department of Applied Chemistry, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2678 |
| Files | Size |
|---|---|
| Dyuthi-T0730.pdf | (3.456Mb) |
| Abstract: | The fabrication and analytical applications of two types of potentiometric sensors for the determination of ketoconazole (KET) are described. The sensors are based on the use of KET-molybdophosphoric acid (MPA) ion pair as electroactive material. The fabricated sensors include both polymer membrane and carbon paste electrodes. Both sensors showed a linear, stable and near Nernstian slope of 57.8mV=decade and 55.2mV=decade for PVC membrane and carbon paste sensors respectively over a relatively wide range of KET concentration (1×10-2-5×10-5 and 1×10-2-1×10-6). The sensors showed a fast response time of <30 sec and <45 sec. A useful pH range of 3–6 was obtained for both types of sensors. A detection limit of 2.96 10 5M was obtained for PVC membrane sensor and 6.91 10 6M was obtained for carbon paste sensor. The proposed sensors proved to have a good selectivity for KET with respect to a large number of ions. The proposed sensors were successfully applied for the determination of KET in pharmaceutical formulations. The results obtained are in good agreement with the values obtained by the standard method. |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/1989 |
| Files | Size |
|---|---|
| Fabrication of potentiometric....pdf | (210.2Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5281 |
| Files | Size |
|---|---|
| Dyuthi T-2317.pdf | (7.868Mb) |
| Description: | Department of Physics, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2133 |
| Files | Size |
|---|---|
| Dyuthi-T0494.pdf | (4.682Mb) |
| Abstract: | Polymer Optical Fibers have occupied historically a place for large core flexible fibers operating in short distances. In addition to their practical passive application in short-haul communication they constitute a potential research field as active devices with organic dopants. Organic dyes are preferred as dopants over organic semiconductors due to their higher optical cross section. Thus organic dyes as gain media in a polymer fiber is used to develop efficient and narrow laser sources with a tunability throughout the visible region or optical amplifier with high gain. Dyes incorporated in fiber form has added advantage over other solid state forms such as films since the pump power required to excite the molecules in the core of the fiber is less thereby utilising the pump power effectively. In 1987, Muto et.al investigated a dye doped step index polymer fiber laser. Afterwards, numerous researches have been carried out in this area demonstrating laser emission from step index, graded index and hollow optical fibers incorporating various dyes. Among various dyes, Rhodamine6G is the most widely and commonly used laser dye for the last four decades. Rhodamine6G has many desirable optical properties which make it preferable over other organic dyes such as Coumarin, Nile Blue, Curcumin etc. The research focus on the implementation of efficient fiber lasers and amplifiers for short fiber distances. Developing efficient plastic lasers with electrical pumping can be a new proposal in this field which demands lowest possible threshold pump energy of the gain medium in the cavity as an important parameter. One way of improving the efficiency of the lasers, through low threshold pump energy, is by modifying the gain of the amplifiers in the resonator/cavity. Success in the field of Radiative Decay Engineering can pave way to this problem. Laser gain media consisting of dye-nanoparticle composites can improve the efficiency by lowering the lasing threshold and enhancing the photostability. The electric field confined near the surface of metal nanoparticles due to Localized Surface Plasmon Resonance can be very effective for the excitation of active centers to impart high optical gain for lasing. Since the Surface Plasmon Resonance of nanoparticles of gold and silver lies in the visible range, it can affect the spectral emission characteristics of organic dyes such as Rhodamine6G through plasmon field generated by the particles. The change in emission of the dye placed near metal nanoparticles depend on plasmon field strength which in turn depends on the type of metal, size of nanoparticle, surface modification of the particle and the wavelength of incident light. Progress in fabrication of different types of nanostructures lead to the advent of nanospheres, nanoalloys, core-shell and nanowires to name a few. The thesis deals with the fabrication and characterisation of polymer optical fibers with various metallic and bimetallic nanostructures incorporated in the gain media for efficient fiber lasers with low threshold and improved photostability. |
| URI: | http://dyuthi.cusat.ac.in/purl/5098 |
| Files | Size |
|---|---|
| Dyuthi-T 2164.pdf | (13.85Mb) |
| Abstract: | In this paper we address the problem of face detection and recognition of grey scale frontal view images. We propose a face recognition system based on probabilistic neural networks (PNN) architecture. The system is implemented using voronoi/ delaunay tessellations and template matching. Images are segmented successfully into homogeneous regions by virtue of voronoi diagram properties. Face verification is achieved using matching scores computed by correlating edge gradients of reference images. The advantage of classification using PNN models is its short training time. The correlation based template matching guarantees good classification results |
| Description: | Nature & Biologically Inspired Computing, 2009. NaBIC 2009. World Congress on |
| URI: | http://dyuthi.cusat.ac.in/purl/4142 |
| Files | Size |
|---|---|
| Face Recognitio ... listic Neural Networks.pdf | (216.3Kb) |
| Abstract: | n this paper we address the problem of face detection and recognition of grey scale frontal view images. We propose a face recognition system based on probabilistic neural networks (PNN) architecture. The system is implemented using voronoi/ delaunay tessellations and template matching. Images are segmented successfully into homogeneous regions by virtue of voronoi diagram properties. Face verification is achieved using matching scores computed by correlating edge gradients of reference images. The advantage of classification using PNN models is its short training time. The correlation based template matching guarantees good classification results. |
| URI: | http://dyuthi.cusat.ac.in/purl/4183 |
| Files | Size |
|---|---|
| Face Recognitio ... listic Neural Networks.pdf | (218.8Kb) |
| Abstract: | A series of novel naphthyridine derivatives 3 and 4 was prepared from substituted pyridine 2 and ketones using ZnCl2 as catalyst under microwave irradiation conditions. All the compounds were evaluated for AChE inhibitory activity and promising compounds 3d, 3e, 4b, and 4g was identified. Representative compounds 3d and 3e were found to show insignificant THLE-2 liver cell viability/toxicity. The binding mode between X-ray crystal structure of human AChE and compounds was studied using molecular docking method and fitness scores were found to be in good correlation with the activity data. |
| Description: | Med Chem Res (2012) 21:1785–1795 DOI 10.1007/s00044-011-9695-0 |
| URI: | http://dyuthi.cusat.ac.in/purl/4162 |
| Files | Size |
|---|---|
| A facile and si ... ivity, and molecular m.pdf | (1.024Mb) |
| Abstract: | A simple and facile strategy for the synthesis of highly substituted imidazoles has been developed by multi-component condensation of 1,2-diketone, aldehyde, amine, and ammonium acetate in presence of tetrabutyl ammonium bromide as catalyst |
| Description: | Res Chem Intermed (2012) 38:359–365 DOI 10.1007/s11164-011-0352-5 |
| URI: | http://dyuthi.cusat.ac.in/purl/4137 |
| Files | Size |
|---|---|
| A facile strate ... iumbromide as catalyst.pdf | (308.6Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5491 |
| Files | Size |
|---|---|
| Dyuthi T-2528.pdf | (4.995Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5197 |
| Files | Size |
|---|---|
| Dyuthi T-2232.pdf | (12.66Mb) |
| Description: | School of Industrial Fisheries, Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/xmlui/purl/2081 |
| Files | Size |
|---|---|
| Dyuthi-T0410.pdf | (20.64Mb) |
| URI: | http://dyuthi.cusat.ac.in/purl/5433 |
| Files | Size |
|---|---|
| Dyuthi T-2474.pdf | (37.92Mb) |
| Abstract: | Given a non empty set S of vertices of a graph, the partiality of a vertex with respect to S is the di erence between maximum and minimum of the distances of the vertex to the vertices of S. The vertices with minimum partiality constitute the fair center of the set. Any vertex set which is the fair center of some set of vertices is called a fair set. In this paper we prove that the induced subgraph of any fair set is connected in the case of trees and characterise block graphs as the class of chordal graphs for which the induced subgraph of all fair sets are connected. The fair sets of Kn, Km;n, Kne, wheel graphs, odd cycles and symmetric even graphs are identi ed. The fair sets of the Cartesian product graphs are also discussed |
| Description: | arXiv preprint arXiv:1304.5378 |
| URI: | http://dyuthi.cusat.ac.in/purl/4230 |
| Files | Size |
|---|---|
| Fair Sets of Some Classes of Graphs.pdf | (443.4Kb) |
| Abstract: | The present study was an attempt to analytically approach the problem of farm poverty in Kerala from an entirely different angle by incorporating an independently developed and reformulated definition of poverty line in terms of physical units of operational holdings (say, acre). The entire discussion on farm poverty emerged out of proper co-ordination of two important factors popularly considered as the distinct features of I<erala's agrarian sector, viz, unparalleled proliferation of marginal holdings and the unique and emirable position enjoyed by the state in terms of farm productivity. This brief analytical study on farm poverty, conducted in the light of inter regional variations in farm productivity tried to highlight various grave issues deserving thorough introspection. |
| Description: | Department of Applied Economics,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2872 |
| Files | Size |
|---|---|
| Dyuthi-T0869.pdf | (5.398Mb) |
| Abstract: | Farm communication and extension programs are vital part of the farm development attempts. Electronic media plays a major role in farm extension activities. Kerala, the consumer state, which was a complete agricultural state in pre-independence period, is the sprouting land of agricultural extension and publication activities in print media. Later AIR (All India Radio) farm programs and farm broadcasting of Doordarshan enriched the role of electronic media in farm extension activities. The media saturated southern state of India received this new electronic media farm communication revolution whole heartedly. However, after 1990, Kerala witnessed a flood of private T V channels and currently there are 24 channels in this regional language, named Malayalam. All major news and entertainment channels are broadcasting farm programs. Farm programs of AIR and Doordarshan, broadcasted in Malayalam language, have been well accepted to the farmers‘ in Kerala. However, post-independence period, witnessed the formation of Kerala state in Indian Union and the first ballot-elected communist Government started its administration. After the land reform bills, the state witnessed a gradual decrease in agricultural production. Even if it is not reflected much in the attitude and practices of farm community and farm broadcast of traditional electronic broadcasting, a change is observable after the post-liberalization era of India. Private Television channels, which were focused on entertainment value of programs, started broadcasting farm programs and the parameters of program production went through certain changes. In this situation, there is ample relevance for a study about the farm programs of electronic media in terms of a comparative study of audience perception. The study is limited in the state of Kerala as it is the most media saturated state in India. The study analyzes the rate, nature and scope of adoption of farming methods transmitted through electronic media (T.V. and Radio) in Malayalam language.All kinds of Farm programs including comprehensive program serials, success stories, seasonal cropping methods, experts opinion, been analyzed on the basis of the following objectives. To find whether propagating new farm methods through farm programs in electronic media or the availability of adequate infrastructure and economic factors make a farmer to adopt a new farming method. To find which electronic media has more influence on farmers to adopt agricultural programs. To find which form of electronic media gets better feedback from farmers To find out whether the programs of T.V. or Radio is more acceptable to farmers than the print media. To find whether farmers gets the message through their preferred medium for the message. The researcher recorded opinions from a panel of agricultural officers, farm Information officers, agro extension researchers and experts. According to their opinions and guidelines, a pilot study is designed and conducted in Kanjikuzhy Panchayath, in Alappuzha district, Kerala. The Panchayath is selected by considering its ideal nature of being the sample for a social Science research. Besides, the nature of farming in the Panchayath, which devoid of the cultivation of cash crops also supported its sample value. As per the observations from the pilot study, researcher confirmed the Triangulation method as the methodology of research. The questionnaire survey, being the primary part contained 42 Questions with 6 independent and 32 dependent variables. The survey is conducted among 400 respondents in Idukki, Alappuzha and Pathanamthitta districts considering geographical differences and distribution of different types of crops. The response from a total of 360 respondents, 120 from each district, finally selected for tabulation and data analysis.The data analysis, based on percentage analysis, along with the results from focus group discussion among a selected group of 20 farmers, together produced the results as follows. Farmers, who are the audience of farm programs, have a very serious approach towards the medium. They are maintaining a critical point of view towards the content of the programs. Farmers are reasonably aware about the financial side of the programs and the monitory aspirations of both private and Government owned Television channels. Even though, the farmers are not aware on the technical terminology and jargons, they have ideas about success stories, program serials and they are even informed about channels are not maintaining an audience research section like AIR. Though the farmers accept Doordarshan as the credential source of farm information and methods, they are inclined to the entertainment value of programs too. They prefer to have more entertainment value for the programs of Doordarshan. Surprisingly, they have very solid suggestions on even about the shots which add entertainment value to the farm broadcasting methods of Doordarshan. Farmers are very much aware about the fact that media is just an instrument for inspiration and persuasion. They strongly believe that the source of information and new methods is agricultural research and an effective change happens only when there are adequate infrastructure and marketing facilities, along with the proper support from Government agricultural guideline and support systems like Krishi Bhavans. They strongly believe that media alone cannot create any magic in increasing agricultural production. Farmers are pointing out the lack of response to the feedback and queries of farmers on farming methods, as an evidence for the difference in levels of commitment of Government and private owned Television channels.Farmers are still perceiving AIR farm programs are far more committed to farmers and farming than any other electronic medium. However, they are seriously lacking Radio receivers with medium wave reception facility. Farmers perceive that the farming methods on new crops are more adoptable than the farming methods of traditional crops in both private and Government owned Television channels. There are multiple factors behind this observation from farmers. Farmers changed in terms of viewing habits and they prefer success stories, which are totally irrelevant and they even think that such stories encourage people to go for farming and they opined that such stories are good sources of inspiration. However, they are all very much sure about the importance and particular about the presence of entertainment factor even in farm programs. Farmers expect direct interaction of any expert of the new farming method to implement the method in their agriculture practices. Though introduction of a new idea in the T.V. is acceptable, farmers need the direct instruction of expert on field to start implementing the new farming practices Farmers still have an affinity towards print media reports and agricultural pages and they have complaints to print media on the removal of agricultural information pages from news papers. They prefer the reports in print media as it facilitates them to collect and refer articles when they need it. Farmers are having an eye of doubt about the credibility of farm programs by private T.V. channels. Even if they prefer private Television channels for listening and adopting new farming methods and other farm information, they scrutinize programs to know whether they are sponsored programs by agrochemical or agro-fertilizer manufacturer. |
| Description: | Department of Applied Economics,Cochin University of Science and Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/2701 |
| Files | Size |
|---|---|
| Dyuthi-T0753.pdf | (7.471Mb) |
| Abstract: | Combinational digital circuits can be evolved automatically using Genetic Algorithms (GA). Until recently this technique used linear chromosomes and and one dimensional crossover and mutation operators. In this paper, a new method for representing combinational digital circuits as 2 Dimensional (2D) chromosomes and suitable 2D crossover and mutation techniques has been proposed. By using this method, the convergence speed of GA can be increased significantly compared to the conventional methods. Moreover, the 2D representation and crossover operation provides the designer with better visualization of the evolved circuits. In addition to this, a technique to display automatically the evolved circuits has been developed with the help of MATLAB |
| Description: | Power, Signals, Controls and Computation (EPSCICON), 2012 International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4525 |
| Files | Size |
|---|---|
| A Faster 2D Tec ... Using GeneticAlgorithm.pdf | (190.8Kb) |
| Abstract: | In this article, techniques have been presented for faster evolution of wavelet lifting coefficients for fingerprint image compression (FIC). In addition to increasing the computational speed by 81.35%, the coefficients performed much better than the reported coefficients in literature. Generally, full-size images are used for evolving wavelet coefficients, which is time consuming. To overcome this, in this work, wavelets were evolved with resized, cropped, resized-average and cropped-average images. On comparing the peak- signal-to-noise-ratios (PSNR) offered by the evolved wavelets, it was found that the cropped images excelled the resized images and is in par with the results reported till date. Wavelet lifting coefficients evolved from an average of four 256 256 centre-cropped images took less than 1/5th the evolution time reported in literature. It produced an improvement of 1.009 dB in average PSNR. Improvement in average PSNR was observed for other compression ratios (CR) and degraded images as well. The proposed technique gave better PSNR for various bit rates, with set partitioning in hierarchical trees (SPIHT) coder. These coefficients performed well with other fingerprint databases as well. |
| Description: | International Journal of Electronics, 2013 Vol. 100, No. 5, 655 -668 |
| URI: | http://dyuthi.cusat.ac.in/purl/4524 |
| Files | Size |
|---|---|
| Faster techniqu ... int image compressions.pdf | (739.7Kb) |
Dyuthi Digital Repository Copyright © 2007-2011 Cochin University of Science and Technology. Items in Dyuthi are protected by copyright, with all rights reserved, unless otherwise indicated.