Abstract: | A broadband rectangular tnicrostrip antenna utilizing an electromagnetically coupled L-strip feed is presented. Experimental study shows a 2:1 VSWR bandwidth of a 10% and excellent cross-polarization performance with a radiation coverage almost as same as that of the rectangular microstrip antenna fed by conventional methods. The variation of bandwidth for different feed parameters is also studied. The proposed antenna is suitable for broadband communications |
URI: | http://dyuthi.cusat.ac.in/purl/1385 |
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PLANAR L-STRIP ... AND MICROSTRIP ANTENNA.PDF | (716.7Kb) |
Abstract: | A compact coplanar waveguide-fed (CPW) monopole antenna for ultra-wideband wireless communication is presented. The proposed antenna comprises of a CPW-fed beveled rectangular patch with a modified slotted ground. The overall size of the antenna is 30 mm 27 mm 1.6 mm. The lower edge of the band is attained by properly decoupling the resonant frequencies due to the extended ground plane and the beveled rectangular patch of the antenna. The upper edge of the radiating band is enhanced by beveling the ground plane corners near the feed point. Experimental results show that the designed antenna operates in the 2.7–12 GHz band, for S11 10 dB with a gain of 2.7–5 dBi. Both the frequency domain and time domain characteristics of the antenna are investigated using antenna transfer function. It is observed that the antenna exhibits identical radiation patterns and reasonable transient characteristics over the entire operating band |
Description: | International Journal of RF and Microwave Computer‐Aided Engineering,VOL 22,issue 5,pp 594-602 |
URI: | http://dyuthi.cusat.ac.in/purl/4331 |
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Planar UWB Ante ... d Slotted Ground Plane.pdf | (963.2Kb) |
Description: | Plasma Science, 2002. ICOPS 2002. IEEE Conference Record-Abstracts. The 29th IEEE International Conference on |
URI: | http://dyuthi.cusat.ac.in/purl/4434 |
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Plasma Assisted ... lyanisidine Thin Films.pdf | (86.27Kb) |
Abstract: | In the present study we assessed plasma and platelet monoamine content using high performance liquid chromatography (HPLC). The study included 22 subjects consisting of 12 freshly-detected male diabetic patients and 10 age and sex-matched healthy controls. The same parameters were measured in streptozotocin -induced diabetic rat models consisting of controls , diabetic and insulin - treated diabetic rats. The platelet counts were significantly reduced (P < 0.05) in rat models as well as human diabetic samples. The plasma norepinephrine (NE) and epinephrine (EPI) concentrations were significantly increased (P < 0.05). The platelet showed a significant increase (P < 0.01) in NE, EPI and serotonin content. Increase in the plasma and platelet content of neurotransmitters may be due to increased sympathetic function, which is an adaptation for the decreased platelet count observed in our study . The results indicate that changes in the neurotransmitter content of the platelet may be a good index to assess the neurotransmitter status in pathological condition such as diabetes mellitus. |
URI: | http://dyuthi.cusat.ac.in/purl/644 |
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jakson James and others(1997)jan.PDF | (2.505Mb) |
Abstract: | The Majority Strategy for finding medians of a set of clients on a graph can be relaxed in the following way: if we are at v, then we move to a neighbor w if there are at least as many clients closer to w than to v (thus ignoring the clients at equal distance from v and w). The graphs on which this Plurality Strategy always finds the set of all medians are precisely those for which the set of medians induces always a connected subgraph |
Description: | Report/Econometric Institute, Erasmus University Rotterdam |
URI: | http://dyuthi.cusat.ac.in/purl/4208 |
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The Plurality Strategy on Graphs.pdf | (149.0Kb) |
Abstract: | Two three-clement polarisation-agile active microstrip patch arrays have been developed . The radiating elements are square patches each with two transistors mounted on adjacent edges. The patches radiate orthogonal modes , the relative phase of which can be varied. Radiation patterns show good agreement with predictions from theory, in both linear and circular polarization, and no grating lobes were observed |
URI: | http://dyuthi.cusat.ac.in/purl/1349 |
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Polarisation ag ... icrostrip patch arrays.PDF | (173.6Kb) |
Abstract: | A new microstrip antenna element is described which exhibits polarization agility. This is achieved by employing a T-slot radiator which is driven by the edge fields of a balanced microstrip line. The balanced line can support two propagating modes. namely. an even mode and an odd mode, and be switching between these modes. the orthogonal arms of the T-slot radiator are separately excited thus forming orthogonally polarized radiated fields. A nucrostrip patch antenna, which displays polarization agility using the sane mechanism, is also described |
URI: | http://dyuthi.cusat.ac.in/purl/1364 |
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POLARIZATION AG ... ARRAY ANTENNA ELEMENT.PDF | (638.8Kb) |
Abstract: | This 'study' deals with a preliminary study of automatic beam steering properly in conducting polyaniline . Polyaniline in its undoped and doped .state was prepared from aniline by the chemical oxidative polymerization method. Dielectric properties of the samples were studied at S-band microwave frequencies using cavity perturbation technique. It is found that undoped po/vanihne is having greater dielectric loss and conductivity contpared with the doped samples. The beam steering property is studied using a perspex rod antenna and HP 85/OC vector network analyzer. The shift in the radiated beam is studied for different do voltages. The results show that polyaniline is a good nutterial far beam steering applications. |
URI: | http://dyuthi.cusat.ac.in/purl/809 |
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Rajesh Menon an ... iline as an...July2007.PDF | (3.204Mb) |
Abstract: | In situ polymerization of aniline is done inside the pillared clay matrix. The nonswellable pillared clay confined matrix allows efficient polymerization that leads to nanofibrous morphology. As a result high polymer order and crystallinity is attained and is evident from XRD patterns. The strong interaction between the clay layers and polyaniline (PANI) is understood from FTIR and DRS spectra. Additionally these analytical results suggest that the prepared PANI is in the doped state. The PANI/pillared clay nanocomposite formation gives additional thermal stability to the polymer backbone and is clear from the DTG curves. |
URI: | http://dyuthi.cusat.ac.in/xmlui/purl/1938 |
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Polyaniline....pdf | (238.4Kb) |
Abstract: | Fine (approximately 18 nm) particles of nickel ferrite were synthesized by the sol-gel technique, and their structural properties were evaluated by X-ray diffraction. Neoprene-based rubber ferrite composites were prepared by incorporating these nickel ferrite powders in the rubber matrix according to a specific recipe. The cure characteristics were analyzed, and the samples were molded into particular shapes whose properties were determined according to ASTM standards. Magnetization studies were carried out using a Vibrating Sample Magnetometer. This study indicates that neoprene rubber-based flexible magnets with desired magnetic properties and appropriate mechanical properties can be prepared by incorporating an adequate amount of nanoscale nickel ferrite particles within the rubber matrix |
Description: | Polymer-Plastics Technology and Engineering, 47: 137–146, 2008 |
URI: | http://dyuthi.cusat.ac.in/purl/4388 |
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Physicomechanic ... ber Ferrite Composites.pdf | (827.3Kb) |
Abstract: | Polymer-solvent interaction parameters for the blends of natural rubber (NR) with styrene-butadiene rubber (SBR) and polybutadiene rubber ( BR) are calculated using the Flory-Rehner equation by equating the network density of the vulcanizates in two solvents. |
URI: | http://dyuthi.cusat.ac.in/purl/834 |
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Rani Joseph an ... ymer solvent..,Nov1986.PDF | (2.916Mb) |
Abstract: | In a sigma-delta analog to digital (A/D) As most of the sigma-delta ADC applications require converter, the most computationally intensive block is decimation filters with linear phase characteristics, the decimation filter and its hardware implementation symmetric Finite Impulse Response (FIR) filters are may require millions of transistors. Since these widely used for implementation. But the number of FIR converters are now targeted for a portable application, filter coefficients will be quite large for implementing a a hardware efficient design is an implicit requirement. narrow band decimation filter. Implementing decimation In this effect, this paper presents a computationally filter in several stages reduces the total number of filter efficient polyphase implementation of non-recursive coefficients, and hence reduces the hardware complexity cascaded integrator comb (CIC) decimators for and power consumption [2]. Sigma-Delta Converters (SDCs). The SDCs are The first stage of decimation filter can be operating at high oversampling frequencies and hence implemented very efficiently using a cascade of integrators require large sampling rate conversions. The filtering and comb filters which do not require multiplication or and rate reduction are performed in several stages to coefficient storage. The remaining filtering is performed reduce hardware complexity and power dissipation. either in single stage or in two stages with more complex The CIC filters are widely adopted as the first stage of FIR or infinite impulse response (IIR) filters according to decimation due to its multiplier free structure. In this the requirements. The amount of passband aliasing or research, the performance of polyphase structure is imaging error can be brought within prescribed bounds by compared with the CICs using recursive and increasing the number of stages in the CIC filter. The non-recursive algorithms in terms of power, speed and width of the passband and the frequency characteristics area. This polyphase implementation offers high speed outside the passband are severely limited. So, CIC filters operation and low power consumption. The polyphase are used to make the transition between high and low implementation of 4th order CIC filter with a sampling rates. Conventional filters operating at low decimation factor of '64' and input word length of sampling rate are used to attain the required transition '4-bits' offers about 70% and 37% of power saving bandwidth and stopband attenuation. compared to the corresponding recursive and Several papers are available in literature that deals non-recursive implementations respectively. The same with different implementations of decimation filter polyphase CIC filter can operate about 7 times faster architecture for sigma-delta ADCs. Hogenauer has than the recursive and about 3.7 times faster than the described the design procedures for decimation and non-recursive CIC filters. |
Description: | Electron Devices and Solid-State Circuits, 2007. EDSSC 2007. IEEE Conference on |
URI: | http://dyuthi.cusat.ac.in/purl/3858 |
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Polyphase Implementation of Non-recursive Comb.pdf | (4.781Mb) |
Abstract: | A set of six new polystyrene anchored metal complexes have been synthesized by the reaction of the metal salt with the polystyrene anchored Schiff base of vanillin. These complexes were characterized by elemental analyses, Fourier transform infrared spectroscopy, diffuse reflectance studies, thermal studies, and magnetic susceptibility measurements. The elemental analyses suggest a metal : ligand ratio of 1 : 2. The ligand is unidentate and coordinates through the azomethine nitrogen. The Mn(II), Fe(III), Co(II), Ni(II), and Cu(II) complexes are all paramagnetic while Zn(II) is diamagnetic. The Cu(II) complex is assigned a square planar structure, while Zn(II) is assigned a tetrahedral structure and Mn(II), Fe(III), Co(II), and Ni(II) are all assigned octahedral geometry. The thermal analyses were done on the ligand and its complexes to reveal their stability. Further, the application of the Schiff base as a chelating resin in ion removal studies was investigated. The polystyrene anchored Schiff base gave 96% efficiency in the removal of Ni(II) from a 20-ppm solution in 15 min, without any interference from ions such as Mn(II), Co(II), Fe(III), Cu(II), Zn(II), U(VI), Na , K , NH4 , Ca2 , Cl , Br , NO3 , NO2 ,and CH3CO2 . The major advantage is that the removal is achieved without altering the pH. |
URI: | http://dyuthi.cusat.ac.in/purl/514 |
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jour appli poly science.pdf | (75.34Kb) |
Abstract: | The effects of feeding of 6-propyllhiouracil (6-I'fU) and potyunsaturatcd fatty acids (I'UFA) independently and ill combination and administration (ip) of a single close of Iriiodothyronine (I',) (2.51ig/IOOg body wl) along with feeding of 6- PTU and PUFA were studied in cal brain. Dopamine (DA), 5-hydroxytryplophan (5-IIl'I'), serolouin (5-Ill), 5-hydioxy indole acetic acid (5-111AA), norepinephrine (NF) :uul ceinephrinn (I?I'l) contenls were assayed in the hypothalannls and ccrc bral cortex regions. It was found that 6-P"l'U Iccding resulted in decrease in dopamine, 5-III', 5 II I I' and 5 IIiAA in both regions. In animals fed wills PUFA followed by adnliuislralion of T,. the I)A level was found normal. |
URI: | http://dyuthi.cusat.ac.in/purl/579 |
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Sheelu Varghese and others(2001)27aug.PDF | (3.405Mb) |
Abstract: | Organic nonlinear optical single crystals of Methyl para-Hydroxy Benzoate (MHB) have been grown using gel-solution technique. These crystals are cut along z-axis and are bombarded with Ag14+ ions of energy 100 MeV. The results show an increase in refractive index at the ion irradiated region. The dielectric constant of the irradiated crystal is increased more than 15 times compared to that of a nonirradiated crystal. The result of these changes and comparative study of second harmonic generation (SHG) efficiency before and after irradiation is discussed. |
URI: | http://dyuthi.cusat.ac.in/purl/2458 |
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Dyuthi-P0319.pdf | (411.5Kb) |
Abstract: | We have studied sea surface temperature (SST) anomalies over the Indian and Pacific Oceans (domain 25 °S to 25°N and 40 °E to 160 °W) during the three seasons following the Indian summer monsoon for wet monsoons and also for dry monsoons accompanied or not by El Ni˜no. A dry monsoon is followed by positive SST anomalies in the longitude belt 40 to 120 °E, negative anomalies in 120 to 160 °E and again positive anomalies east of 160 °E. In dry monsoons accompanied by El Ni˜no the anomalies have the same sign, but are much stronger. Wet monsoons have weak anomalies of opposite sign in all three of the longitude belts. Thus El Ni˜no and a dry monsoon have the same types of association with the Indian and Pacific Ocean SSTs. In the sector 40 to 120 °E SST anomalies first appear over the western part of the Indian Ocean (June to September) followed by the same sign of anomalies over its eastern part and China Sea (October to March). By March after a dry monsoon or El Ni˜no the Indian Ocean between 10 °N and 10 °S has a spatially large warm SST anomaly. Anomalies in deep convection tend to follow the SST anomalies, with warm SST anomalies producing positive convection anomalies around the seasonal location of the intertropical convergence zone |
Description: | Int. J. Climatol. 22: 559–567 (2002) |
URI: | http://dyuthi.cusat.ac.in/purl/3782 |
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CAB.PVJ_Int.Clim.pdf | (302.3Kb) |
Abstract: | Pseudomonas aeruginosa MCCB 123 was grown in a synthetic medium for β-1,3 glucanase production. From the culture filtrate, β-1,3 glucanase was purified with a molecular mass of 45 kDa. The enzyme was a metallozyme as its β-1,3 glucanase activity got inhibited by the metal chelator EDTA. Optimum pH and temperature for β-1,3 glucanase activity on laminarin was found to be 7 and 50 °C respectively. The MCCB 123 β-1,3 glucanase was found to have good lytic action on a wide range of fungal isolates, and hence its application in fungal DNA extraction was evaluated. β-1,3 glucanase purified from the culture supernatant of P. aeruginosa MCCB 123 could be used for the extraction of fungal DNA without the addition of any other reagents generally used. Optimum pH and temperature of enzyme for fungal DNA extraction was found to be 7 and 65 °C respectively. This is the first report on β-1,3 glucanase employed in fungal DNA extraction |
Description: | Indian Journal of Experimental Biology Vol.52, January 2014, pp. 89-96 |
URI: | http://dyuthi.cusat.ac.in/purl/4083 |
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Potential appli ... fungal DNA extraction.pdf | (1.470Mb) |
Abstract: | Prevalence of faecal coliform bacteria and the survival of Escherichia coli, Vibrio parahaemolyticus and Salmonella paratyphi were studied in the water and sediment from Vembanadu Lake in the presence and absence of protozoan predators. The density of faecal coliform bacteria ranged between mean MPN value 5080–9000/100 ml in water and 110,000–988,000/1 g in sediment (p <0.01), which was 110 times greater than in overlying water. The laboratory microcosm studies revealed that E. coli, V. parahaemolyticus and S. paratyphi showed significantly higher survival (p <0.05) potential in sediment than in overlying water both in the presence and absence of protozoan predators. The results indicate that Vembanadu Lake sediment constitutes a reservoir of pathogenic bacteria and exhibits potential health hazard from possible resuspension and subsequent ingestion during recreational activities. Therefore, assessment of bacterial concentration in freshwater lake sediments used for contact and non-contact recreation is of considerable significance for the proper assessment of microbial pollution of the overlying water and the management and protection of related health risk at specific recreational sites. In addition, assessment of the bacterial concentration in sediments can be used as a relatively stable indicator of long-term mean bacterial concentration in the water column above. |
Description: | Water Qual Expo Health (2010) 2: 105–113 |
URI: | http://dyuthi.cusat.ac.in/purl/3954 |
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Potential Expos ... Vembanadu Lake, India.pdf | (918.0Kb) |
Abstract: | To assess the prevalence of faecal coliform bacteria and multiple drug resistance among Escherichia coli and Salmonella serotypes from Vembanadu Lake. Study design: Systematic microbiological testing. Methods: Monthly collection of water samples were made from ten stations on the southern and northern parts of a salt water regulator constructed in Vembanadu Lake in order to prevent incursion of seawater during certain periods of the year. Density of faecal colifrom bacteria was estimated. E. coli and Salmonella were isolated and their different serotypes were identified. Antibiotic resistance analysis of E. coli and Salmonella serotypes was done and the MAR index of individual isolates was calculated. Results: Density of faecal coliform bacteria ranged from mean MPN value 2900 -7100/100ml. Results showed multiple drug resistance pattern among the bacterial isolates. E. coli showed more than 50% resistance to amickacin, oxytetracycline, streptomycin, tetracycline and kanamycin while Salmonella showed high resistance to oxytetracycline, streptomycin, tetracycline and ampicillin. The MAR indexing of the isolates showed that they have originated from high risk source such as humans, poultry and dairy cows. Conclusions: The high density of faecal coliform bacteria and prevalence of multi drug resistant E. coli and Salmonella serotypes in the lake may pose severe public health risk through related water borne and food borne outbreaks |
Description: | Public health 1 2 5 ( 2 0 1 1 ) 3 7 7-3 7 9 |
URI: | http://dyuthi.cusat.ac.in/purl/3917 |
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Potential publi ... f faecal contamination.pdf | (99.36Kb) |
Abstract: | A fairly rigorous analytical treatment of the power characteristics of dielectric optical waveguides with Piet Hein core-cross sectional geometry is presented in this paper. This kind of wareguide structure would be advantageous owing to the absence of corners, which are found in rectangular guides, resulting in undesirable loss (hit to the scattering of light. In order to simplify this theoretical approach. em approximation of vanishing refractive index difference between the guiding and the non-guiding sections is implemented. The variation eJ logarithmic power is shown for different dimensions of the core, corresponding to different azimuthal modal indices. It is found that the nutlet with higher index values carry less logaritlunic power in the lower tail of the propagation 's constant range, and this feature affects the higher tail. A better kind of uniformity of the power distribution is observed near the higher tail of the range of propagation Constants |
URI: | http://dyuthi.cusat.ac.in/purl/1396 |
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Power character ... l piet hein waveguides.PDF | (136.2Kb) |
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