| Abstract: | We have investigated the third-order nonlinearity in ZnO nanocolloids with particle sizes in the range 6-18 nm by the z-scan technique. The third-order optical susceptibility χ(3) increases with increasing particle size (R) within the range of our investigations. In the weak confinement regime, an R2 dependence of χ(3) is obtained for ZnO nanocolloids. The optical limiting response is also studied against particle size. |
| URI: | http://dyuthi.cusat.ac.in/purl/2586 |
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| Dyuthi-P0146.pdf | (755.0Kb) |
| Abstract: | In this article we present size dependent spectroscopic observations of nanocolloids of ZnO. ZnO is reported to show two emission bands, an ultraviolet (UV) emission band and another in the green region. Apart from the known band gap 380 nm and impurity 530 nm emissions, we have found some peculiar features in the fluorescence spectra that are consistent with the nanoparticle size distribution. Results show that additional emissions at 420 and 490 nm are developed with particle size. The origin of the visible band emission is discussed. The mechanism of the luminescence suggests that UV luminescence of ZnO colloid is related to the transition from conduction band edge to valence band, and visible luminescence is caused by the transition from deep donor level to valence band due to oxygen vacancies and by the transition from conduction band to deep acceptor level due to impurities and defect states. A correlation analysis between the particle size and spectroscopic observations is also discussed. |
| URI: | http://dyuthi.cusat.ac.in/purl/2639 |
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| Dyuthi-P0326.pdf | (963.7Kb) |
| Abstract: | Silver silica nanocomposites were obtained by the sol–gel technique using tetraethyl orthosilicate (TEOS) and silver nitrate (AgNO3) as precursors. The silver nitrate concentration was varied for obtaining composites with different nanoparticle sizes. The structural and microstructural properties were determined by x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopic (XPS) studies were done for determining the chemical states of silver in the silica matrix. For the lowest AgNO3 concentration, monodispersed and spherical Ag crystallites, with an average diameter of 5 nm, were obtained. Grain growth and an increase in size distribution was observed for higher concentrations. The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5–10 nm is studied. For decreasing nanoparticle size, a redshift and broadening of the plasmon-related absorption peak was observed. The observed redshift and broadening of the SPR band was explained using modified Mie scattering theory |
| Description: | Nanotechnology 19 (2008) 075710 (7pp) |
| URI: | http://dyuthi.cusat.ac.in/purl/4352 |
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| Size-dependent ... silica nanocomposites.pdf | (858.7Kb) |
| Abstract: | A novel dual frequency design of a square microstrip antenna coaxially fed along the diagonal with a chip capacitor mounted at the bottom of the stub is introduced. This design provides enhanced area reduction and good cross-polarization levels. The antenna design can be used as a compact antenna system where limited size is a major requirement. The details of the antenna design and experimental results are presented |
| URI: | http://dyuthi.cusat.ac.in/purl/1382 |
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| Slot coupled sq ... al-frequency operation.PDF | (1.351Mb) |
| Abstract: | A slot line fed planar dipole antenna with a parasitic strip for wide band applications is presented. The presented antenna offers a 2:1 VSWR bandwidth from 1.66 to 2.71 GHz covering the DCS/ PCS/UMTS and IEEE 802.11b/g bands with a gain better than 6.5 dBi. The uniplanar design, simple feeding, and high gain make it a versatile antenna for wireless applications |
| Description: | MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 51, No. 3, March 2009 |
| URI: | http://dyuthi.cusat.ac.in/purl/4321 |
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| Slot Line Fed D ... Wide Band Applications.pdf | (416.4Kb) |
| Abstract: | Dual frequency operation is achieved from a compact microstrip antenna by loading a pair of narrow slots close to its radiating edges. The two frequencies have parallel polarization planes and similar radiation characteristics. The ratio between the two operating frequencies can be tuned in the range (1.14-1. 24), which is much smaller than that of similar designs. The above excellent radiation characteristics are achieved along with an area reduction of - 75% compared to the standard rectangular patch |
| URI: | http://dyuthi.cusat.ac.in/purl/1378 |
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| Slot-loaded com ... al-frequency operation.PDF | (1.081Mb) |
| Abstract: | The concept of social clause has been accepted in the GATT agreement to prescribe the labour standards. Social clause , $tands for protecting labour standards, more specificalfy prohibition of employment of children in hazardous industries, providing adequate wages. healthy and hygienic working conditions, special social welfare protection for women, prescription of hours of work and rest and provision for efficacious remedy in case of default by employer to provide these conditions to his workers. |
| Description: | SOUTHERN ECONOMIST - JUNE 1, 1997 |
| URI: | http://dyuthi.cusat.ac.in/purl/4294 |
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| Social Clause of WTO and India.pdf | (152.4Kb) |
| Abstract: | Tourism is an industry which is heavily dependent on marketing. Mouth to mouth communication has played a major role in shaping a number of destinations.This is particularly true in modern parlance.This is social networking phenomenon which is fast spreading over the internet .Many sites provide visitors a lot of freedom to express their views.Promotion of a destination depends lot on conversation and exchange of information over these social networks.This paper analyses the social networking sites their contribution to marketing tourism and hoapitality .The negetive impacts phenomena are also discussed |
| Description: | Indian Journal of Tourism and Hospitality Management Vol.11 No.2 Dec 2010 |
| URI: | http://dyuthi.cusat.ac.in/purl/4295 |
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| Social Media- A ... hospitality marketing.pdf | (337.6Kb) |
| Abstract: | The paper is an attempt to shed light on the socio-economic aspects of the local communities on the development of ecotourism in Kerala. Most of the local communities in the ecotourism destinations are tribes who have been excluded from the mainstream society and are not a part of Kerala’s overall development setting. The paper also tries to situate the community perception on the sustainable livelihood of ecotourism sites of Kerala. Data for the study is obtained from a primary survey by dividing the ecotourism destinations in Kerala into three zones, 230 from south zone, 220 from central zone and 200 from north zone with a total sample size of 650 based on the notion of community based ecotourism initiatives of the state. The result of the study confirms that ecotourism has helped to enhance the livelihood of the marginalized community. With well-knit policies it is possible to tag ecotourism of Kerala as an important tourism destination in the global tourism map |
| Description: | Research on Humanities and Social Sciences,Vol 2, No.11, 2012 |
| URI: | http://dyuthi.cusat.ac.in/purl/4591 |
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| Socio-Economic ... mentThe Case of Kerala.pdf | (701.7Kb) |
| Abstract: | This paper describes certain findings of intonation and intensity study of emotive speech with the minimal use of signal processing algorithms. This study was based on six basic emotions and the neutral, elicited from 1660 English utterances obtained from the speech recordings of six Indian women. The correctness of the emotional content was verified through perceptual listening tests. Marked similarity was noted among pitch contours of like-worded, positive valence emotions, though no such similarity was observed among the four negative valence emotional expressions. The intensity patterns were also studied. The results of the study were validated using arbitrary television recordings for four emotions. The findings are useful to technical researchers, social psychologists and to the common man interested in the dynamics of vocal expression of emotions |
| Description: | Procedia Engineering 30 (2012) 577 – 583 |
| URI: | http://dyuthi.cusat.ac.in/purl/4529 |
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| A socio friendl ... ysis of emotive speech.pdf | (336.4Kb) |
| Abstract: | Rare earth metal ion exchanged (La3+, Ce3+, RE3+) KFAU-Y zeolites were prepared by simple ion-exchange methods and have been characterized using different physico-chemical techniques. In this paper a novel application of solid acid catalysts in the dehydration/ Beckmann rearrangement of aldoximes; benzaldoxime and 4-methoxybenzaldoxime is reported. Dehydration/Beckmann rearrangement reactions of benzaldoxime and 4-methoxybenzaldoxime is carried out in a continuous down flow reactor at 473K. 4-Methoxybenzaldoxime gave both Beckmann rearrangement product (4-methoxyphenylformamide) and dehydration product (4-methoxybenzonitrile) in high overall yields. The difference in behavior of the aldoximes is explained in terms of electronic effects. The production of benzonitrile was near quantitative under heterogeneous reaction conditions. The optimal protocol allows nitriles to be synthesized in good yields through the dehydration of aldoximes. Time on stream studies show a fast decline in the activity of the catalyst due to neutralization of acid sites by the basic reactant and product molecules. |
| URI: | http://dyuthi.cusat.ac.in/purl/2253 |
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| Dyuthi-SS48.pdf | (495.6Kb) |
| Abstract: | The rising pressure of Population, together with the constantly changing technologies, and development perspectives, contribute to the ever increasing volumes of wastes in different forms. The solid and liquid wastes generated in the urban areas were considered a burden to the society, and hazardous to the environment. The fact is that the growth of consumerist culture and aimless throwing of refuse by the people created the outbreak of environmental pollution. Unhygienic environment and solid waste accumulation coincided with mosquito breeding which causes, the spread of most epidemics. The rationale behind most of the diseases is the unhygienic pattern followed by the people both in rural and urban areas. As an environmental package, the disposal of solid waste from different sources, such as house holds markets, commercial areas, slaughter houses, hospitals and industries, therefore assumed crucial importance. So as a part of the theory and practice, a study on the area, solid waste management of Arppukara Grama Panchayat of Kottayam district is taken into consideration. The study conducted here proposes, to examine the quality and quantity of the solid waste generated in the panchayat and also it's impact on the existing social, economical, environmental and ecological systems |
| Description: | Journal of Global Economy, Volume 6 No 1, JANUARY-FEBRUARY, 2010 |
| URI: | http://dyuthi.cusat.ac.in/purl/4300 |
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| Solid Waste Man ... udy of Arppukara Grama.pdf | (832.0Kb) |
| URI: | http://dyuthi.cusat.ac.in/purl/727 |
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| Sreekumar,K,ed.and Saritha G Bhat,SWM.PDF | (3.920Mb) |
| Abstract: | The phenomenon of two-soliton resonances of the Kadomtsev-Petviashvilli equation for the superfluid surface density fluctuation in He films is studied. The velocity of the resonant soliton is obtained. |
| URI: | http://dyuthi.cusat.ac.in/purl/2561 |
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| Dyuthi-P0120.pdf | (384.2Kb) |
| Abstract: | The dynamics of saturated two-dimensional superfluid4He films is shown to be governed by the Kadomtsev-Petviashvili equation with negative dispersion. It is established that the phenomena of soliton resonance could be observed in such films. Under the lowest order nonlinearity, such resonance would happen only if two dimensional effects are taken into account. The amplitude and velocity of the resonant soliton are obtained. |
| URI: | http://dyuthi.cusat.ac.in/purl/2568 |
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| Dyuthi-P0127.pdf | (427.3Kb) |
| Abstract: | Solubilities of 4-nitrobenzoic acid at 25°, 35° and 42°C have been determined in water and in the presence of several concentrations of electrolytes. The free energies, enthalpies and entropies of transfer are also reported. The data have been rationalized by considering the structure-breaking effects of the ions of the salts and the requirement of the localized hydrolysis model. The theory of Symons is not satisfactory to rationalise the experimental data. |
| URI: | http://dyuthi.cusat.ac.in/purl/2222 |
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| Dyuthi-SS26.pdf | (149.8Kb) |
| Abstract: | Dual beam thermal lens tecbnique is successfully employed for the determination of absolute Fluorescence quantum yield of rhodamine 6G lnser dye in different solvents. A 532 nm radiation from a Q-switched Nd:YAG laser was used for the excitation purpose. The fluorescence quantum yield values are found to be strongly influenced by environmental effects. It has been observed that fluorescence yield is greater for rhodamine 6G in ethylene glycol system than in water or in methanol. Our results also indicate that parameters like concentration of the dye solution, aggregate formation and excited state absorption affect the absolute values of fluorescence yield significantly. |
| URI: | http://dyuthi.cusat.ac.in/purl/2474 |
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| Dyuthi-P0209.pdf | (681.9Kb) |
| Abstract: | Somatic embryos were induced from scutellar callus of immature zygotic embryos of T aestivum cv. Chinese Spring. Observations on precociously germinating somatic embryos revealed that: (i) In the initial stages the coleoptile is split, exposes the shoot apex and forms a green trichomatous leafy structure. In the germinating zygotic embryo, the coleoptile is tubular, (ii) Unlike what has been inferred earlier the leafy structure is the coleoptile and not the scutellum, (iii) Bipolarity of the embryoid is established later when root develops at the basal end. |
| URI: | http://dyuthi.cusat.ac.in/purl/740 |
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| Padma Nambisan ... bryogenesis...,Jan1992.PDF | (2.812Mb) |
| Abstract: | When simulation modeling is used for performance improvement studies of complex systems such as transport terminals, domain specific conceptual modeling constructs could be used by modelers to create structured models. A two stage procedure which includes identification of the problem characteristics/cluster - ‘knowledge acquisition’ and identification of standard models for the problem cluster – ‘model abstraction’ was found to be effective in creating structured models when applied to certain logistic terminal systems. In this paper we discuss some methods and examples related the knowledge acquisition and model abstraction stages for the development of three different types of model categories of terminal systems |
| Description: | Proceedings of the World Congress on Engineering and Computer Science 2012 Vol II WCECS 2012, October 24-26, 2012, San Francisco, USA |
| URI: | http://dyuthi.cusat.ac.in/purl/4666 |
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| Some Aspects of ... ic Terminal operations.pdf | (565.9Kb) |
| Abstract: | Two graphs G and H are Turker equivalent if they have the same set of Turker angles. In this paper some Turker equivalent family of graphs are obtained. |
| URI: | http://dyuthi.cusat.ac.in/purl/643 |
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| Turker equivale ... for graph theory notes.pdf | (161.4Kb) |
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