Environmental set-up and tidal propagation in a tropical estuary with dual connection to the sea (SW Coast of India)

The Kochi Backwater (KB) is the second largest wetland system in India. It is connected to the sea at Fort Kochi and Munambam (Pallipuram) (30 km north of Kochi). As the tide is forced through two openings, its propagation in the backwater system is very complicated, particularly in the northern arm of the estuary. Using synchronous water level (WL) and current measurements in the KB from a network of stations during 2007-2008, it was convenient to demarcate the northern KB into two distinct regions according to the tidal forcing from the north (Pallipuram) and south (Vallarpadam). This demarcation is useful for computing the propagation speeds of the dominant tidal constituents in the northern branch of the KB with dual opening for opposing tides. WL variations indicated that M 2 tide (Principal lunar semidiurnal constituent) dominated in the sea level variance, followed by the K 1 constituent (Luni-solar declinational diurnal constituent). The M 2 tidal influence was the strongest near the mouth and decayed in the upstream direction. The propagation speed of the M 2 tide in the southern estuary was ~3.14 m/s. The ratio of the total annual runoff to the estuarine volume is ~42 that indicates the estuary will be flushed 42 times in a year. KB can be classified as a monsoonal estuary where the river discharge exhibits large seasonal variation

Development of selected electro-active polymer-ceramic nanocomposites as pyroelectric thermal/infrared detector materials

The present work emphasises on the synthesis and characterization of electro-active polymer-ceramic nanocomposites which can be used for pyroelectric thermal/infrared detection applications. Two sets of samples belong to polymer-microcrystalline composites have also been investigated in the work. The polymers used in the work have been commercially available ones, but the nanoceramics have been synthesized following simple chemical routes and aqueous organic gel routes. After characterizing the nanoceramics for their structure by powder XRD, they have been dispersed in liquid polymer and sonicated for uniform dispersion. The viscous mixture so formed was cast in the form of films for experimentation. Samples with volume fraction of the ceramic phase varied from 0 to 0.25 have been prepared. Solution growth was followed to prepare microcrystalline samples for the polymer-microcrystalline composites. The physical properties that determine the pyroelectric sensitivity of a material are dielectric constant, dielectric loss, pyroelectric coefficient, thermal conductivity and specific heat capacity. These parameters have been determined for all the samples and compositions reported in this work.The pyroelectric figures of merit for all the samples were determined. The pyroelectric figures of merit that determine the pyroelectric sensitivity of a material are current sensitivity, voltage responsivity and detectivity. All these have been determined for each set of samples and reported in the thesis. In order to assess the flexibility and mouldability of the composites we have measured the Shore hardness of each of the composites by indentation technique and compared with the pyroelectric figures of merit. Some important factors considered during the material fabrication stages were maximum flexibility and maximum figures of merit for pyroelectric thermal/IR detection applications. In order to achieve these goals, all the samples are synthesized as composites of polymers and nano/microcrystalline particles and are prepared in the form of freestanding films. The selected polymer matrices and particle inclusions possess good pyroelectric coefficients, low thermal and dielectric properties, so that good pyroelectric figures of merit could be achieved. The salient features of the work include the particle size of the selected ceramic materials. Since they are in nanometer size it was possible to achieve high flexibility and moldability with high figures of merit for even low volume fractions of inclusions of the prepared nanocrystalline composites. In the case of microcrystalline TGS and DTGS, their composites in PU matrix protect them from fragility and humidity susceptibility and made them for environmental friendly applications.Cochin University Of Science And TechnologyDepartment of Instrumentatio

Lipomatous mixed tumor of the skin with predominance of stromal fat

A rare variant of cutaneous chondroid syringoma, with epithelial differentiation composed of apocrine, follicular, and sebaceous components and showing the presence of predominantly lipomatous stroma, is being reported in a 54-year-old female

Planktonic foraminifera in waters off the Coromandel coast, Bay of Bengal

1-7Living planktonic foraminifers have been studied in relation to their ecology and distribution with plankton samples collected in January from the east coast of India. During this period, upwelling occurs in the northwestern Bay of Bengal and as a result, besides higher populations of Foraminifera in the northeastern part of the coast, upwelling indicator species such as Globigerina butloides and Neogloboquodrina dutertrei are also discernible in the fauna. Species diversity, equitability, and coexistence of various foraminiferal species of the samples are compared. Further, the degree of fauna] affinity for different sites is discussed

Analyses of significant features of L-Prolinium Picrate single crystal: An excellent material for non linear optical applications

Today the fundamental aspect of the researchers is to explore maximum physical properties of the material for device fabrication. In the present article, single crystal X-ray diffraction has been carried out to verify the formation of the synthesized compound. In addition to that, powder X-ray diffraction has been performed to obtain diffraction pattern of (L)-Prolinium Picrate single crystal. The strain present inside the single crystal was measured using Hall-Williamson equation from PXRD measurements. The dark current and photon current was obtained from photoconductivity technique whose plot depicted that the sample was negative photoconducting material. Optical homogeneity of the single crystal was analyzed using birefringence technique. Its resistance towards Nd: YAG laser was scrutinized for (L)-Prolinium Picrate single crystal by applying 1 pulse per second. Different thermal parameters like thermal conductivity, thermal diffusivity, thermal effusivity and specific heat were computed using photopyroelectric technique. Solid state parameters were calculated from Clausius Mossotti relation by taking structural information of the title compound. Also, optical parameters like refractive index, reflectance etc were calculated through UV-Vis NIR analysis

Nonlinear optical single crystal of L-Cystine hydrochloride: Insights into the crystalline perfection, thermal, mechanical and optical properties for device fabrication

Now days, nonlinear optical materials are subjected to extensive research owing to their versatility towards various photonic applications. In the present article, twin free L-Cystine hydrochloride single crystals were grown using conventional slow evaporation solution technique. The powder X-ray diffraction pattern confirmed that the titled compound belongs to monoclinic crystal system having space group C-2. Using FWHM of each diffracting peak, the strain present within the lattice was calculated. Through High Resolution XRD, the crystal quality was scrutinized and found that the grown single crystal is free from any type of defects and grain boundaries. For examination of optical homogeneity of the crystal, birefringence studies were conducted which revealed that there is only one fringe in the interferogram suggesting a good optical homogeneity. Further, various thermal transport parameters were calculated using Photopyroelectric technique. Apart from that, its mechanical strength was assessed at nanoscale through Nano indentation technique. Piezoelectric and ferroelectric studies were also carried out on the filed compound

Bulk growth of ninhydrin single crystals by solvent evaporation method and its characterization for SHG and THG applications

Ninhydrin is a well-known compound generally used in amino acid synthesis and also for detecting the latent fingerprints on porous surfaces. Single crystals can be grown by dissolving the compound in double distilled water at ambient temperature, and can be used as a potential material for second and third harmonic generation applications. The grown specimen was subjected to different characterization techniques in order to find out its suitability for device fabrication. Its lattice dimensions have been confirmed by X-ray powder diffraction and its crystalline quality has been assessed by high resolution X-ray diffraction and X-ray topography methods. The presence of functional groups was identified from HETCOR analysis and confirmed the absence of impurities during crystallization. Its optical properties have been examined by photoluminescence and birefringence analyses. Its thermal parameters such as thermal diffusivity, thermal conductivity and specific capacity have been carried out by following photopyroelectric method. Third order nonlinear optical measurements have been carried out using Z-scan technique and its nonlinear optical absorption coefficient has been determined

Dopamine functionalization of BaTiO 3 : an effective strategy for the enhancement of electrical, magnetoelectric and thermal properties of BaTiO 3 -PVDF-TrFE nanocomposites

International audienc

Crystalline perfection, thermal, mechanical and optical investigations on solution grown-arginine monohydrochloride single crystal

In the present work we report crystallization and detailed analyses on l-arginine monohydrochloride single crystal an efficient material for nonlinear optical applications. The crystal of titled material was grown using slow evaporation solution growth technique using double distilled water as solvent. Single crystal X-ray diffraction technique revealed that lattice dimensions of grown crystal are in good agreement with the reported literature and it crystallised in monoclinic crystal system. High resolution X-ray diffraction study revealed that crystalline perfection is fairly good. Optical homogeneity and variation of birefringence across the sample cross-section was studied using birefringence interferometer. Specific heat and thermal conductivity of grown crystal was measured using photopyroelectric technique and was found to be higher than many organic and inorganic crystals. Its various mechanical properties and resistance toward deformation was examined using nano-indentation technique. Further laser damage threshold value and phase matching angle was also measured