664 research outputs found

    Promoting the Recovery of a True Mangrove- Avicennia Marina in Ecogeographic Area of Puthuvypeen

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    A study was conducted in a disturbed mangrove forest that had been gazetted as a site under governmental area. This study provides information regarding the status of disturbed mangroves and can be used as baseline data to support decision making in managing mangrove forests. The study were to determine the tree species exploited in mangrove forest. This recovery study was carried out in the upcoming industrial area of Puthuvypeen. Puthuvypeen ecogeographic area is clearly categorized as a mangrove forest that has a uniform single-layered canopy with trees reaching up to an average 15-25cm GBH and 25-30m in height. Generally there are mixed- mangrove forests of Avicennia marina and Avicennia officinalis . This ecogeographic area of Puthuvypeen may now also be known as “ vanishing mangroves. ” Even under severe degradation, Avicennia marina species still shows its adaptation capacity under stressful condition with re-sprouting from in and around the destroyed trees. In general, the species composition of Puthuvypeen geographic area is rich and the regeneration status is good for the recovery of the species

    Measurement of Devolatilization Time and Transient Shrinkage of a Cylindrical Wood Particle in a Bubbling Fluidized Bed Combustor”,

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    ABSTRACT This work presents the results of experiments conducted to determine the mass loss and size reduction characteristics of a cylindrical wood particle undergoing devolatilization under oxidation conditions in a bubbling fluidized bed combustor. Cylindrical wood particles having five different sizes ranging from 10 to 30 mm and aspect ratio (l/d=1) have been used for the study. Experiments were conducted in a lab scale bubbling fluidized bed combustor having silica sand as the inert bed material and air as the fluidizing medium. Devolatilization time, and radial and longitudinal shrinkages have been measured during and at the end of devolatilization. Studies have been carried out at three different bed temperatures (T bed =750, 850 and 950 °C), two inert bed material sizes (mean size d p =375 and 550 µm) and two fluidizing velocities (u=5u mf and u=10u mf ). Devolatilization time is most influenced by the initial wood size and bed temperature. Longitudinal shrinkage begins after 50% of conversion while radial shrinkage occurs right from the beginning. There was no clear influence of the fluidization velocity and bed particle size on the parameters studied

    Natural Frequency based delamination estimation in GFRP beams using RSM and ANN

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    The importance of delamination detection can be understood from aircraft components like Vertical Stabilizer, which is subjected to heavy vibration during the flight movement and it may lead to delamination and finally even flight crash can happen because of that. Any solid structure's vibration behaviour discloses specific dynamic characteristics and property parameters of that structure. This research investigates the detection of delamination in composites using a method based on vibration signals.  The composite material's flexural stiffness and strength are reduced as a result of delaminations, and vibration properties such as natural frequency responses are altered. In inverse problems involving vibration response, the response signals such as natural frequencies are utilized to find the location and magnitude of delaminations. For different delaminated beams with varying position and size, inverse approaches such as Response Surface Methodology (RSM) and Artificial Neural Network (ANN) are utilized to address the inverse problem, which aids in the prediction of delamination size and location

    Artificial neural network based delamination prediction in composite plates using vibration signals

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    Dynamic loading on composite components may induce damages such as cracks, delaminations, etc. and development of an early damage detection technique for delaminations is one of the most important aspects in ensuring the integrity and safety of composite components. The presence of damages such as delaminations on the composites reduces its stiffness and further changes the dynamic behaviour of the structures. As the loss in stiffness leads to changes in the natural frequencies, mode shapes, and other aspects of the structure, vibration analysis may be the ideal technique to employ in this case. In this research work, the supervised feed-forward multilayer back-propagation Artificial Neural Network (ANN) is used to determine the position and area of delaminations in GFRP plates using changes in natural frequencies as inputs. The natural frequencies were obtained by finite element analysis and results are validated by experimentation. The findings show that the suggested technique can satisfactorily estimate the location and extent of delaminations in composite plates

    FABRICATION OF DRUG DELIVERY SYSTEM FOR CONTROLLED RELEASE OF CURCUMIN, INTERCALATED WITH MAGNETITE NANOPARTICLES THROUGH SODIUM ALGINATE/POLYVINYLPYRROLIDONE-CO-VINYL ACETATE SEMI IPN MICROBEADS

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    Objective: The aim of the present work is to fabricate curcumin (CUR) encapsulated microbeads in the polymer matrix of sodium alginate (SA)/poly(vinylpyrrolidone)-co-vinyl acetate (PVP-co-VAc) intercalated with magnetite nanoparticles (MNPs) using glutaraldehyde (GA)/calcium chloride CaCl2 as the crosslinker. Methods: Magnetite nanoparticles (MNPs) were synthesized by a modified co-precipitation method. Curcumin encapsulated SA/PVP-co-VAc microbeads, intercalated with MNPs were prepared by simple ionotropic gelation technique. The formation of microbeads and uniform distribution of curcumin were characterized using spectroscopic methods. In addition, swelling and drug release kinetic studies of the microbeads were performed in simulated intestinal fluid (pH 7.4) and simulated gastric fluid (pH 1.2) at 37 °C. Results: Microbeads formation was confirmed by Fourier Transform Infrared (FTIR). Differential Scanning Calorimetry (DSC) studies reveal that the peak at 181 °C of CUR was not observed in CUR loaded microbeads, which confirms that CUR was encapsulated at the molecular level in the polymer matrix. The X-Ray diffraction (X-RD) diffractograms of CUR shows 2Ө peaks between 12-28 °, which indicated the crystalline nature of CUR, these peaks are not found in CUR loaded microbeads, suggesting that the drug has been molecularly dispersed in the polymer matrix. The X-RD 2Ө peaks of MNPs are observed in the MNPs loaded microbeads, which confirms that MNPs are successfully loaded in the microbeads. The swelling studies and in vitro release studies were performed at pH 1.2 and 7.4. The results reveal that at pH 7.4 highest swelling and release was observed, which confirms that the developed microbeads are pH sensitive and are suitable for intestinal drug delivery. The drug release kinetics fit into the Korsmeyer-Peppas equation, indicating non-Fickian diffusion. Conclusion: The results concluded that the present system as dependent on pH of the test medium and hence suggest suitability for intestinal drug delivery

    Use of spatiotemporal characteristics of ambient PM2.5 in rural South India to infer local versus regional contributions

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    This study uses spatiotemporal patterns in ambient concentrations to infer the contribution of regional versus local sources. We collected 12 months of monitoring data for outdoor fine particulate matter (PM2.5) in rural southern India. Rural India includes more than one-tenth of the global population and annually accounts for around half a million air pollution deaths, yet little is known about the relative contribution of local sources to outdoor air pollution. We measured 1-min averaged outdoor PM2.5 concentrations during June 2015-May 2016 in three villages, which varied in population size, socioeconomic status, and type and usage of domestic fuel. The daily geometric-mean PM2.5 concentration was approximately 30mugm(-3) (geometric standard deviation: approximately 1.5). Concentrations exceeded the Indian National Ambient Air Quality standards (60mugm(-3)) during 2-5% of observation days. Average concentrations were approximately 25mugm(-3) higher during winter than during monsoon and approximately 8mugm(-3) higher during morning hours than the diurnal average. A moving average subtraction method based on 1-min average PM2.5 concentrations indicated that local contributions (e.g., nearby biomass combustion, brick kilns) were greater in the most populated village, and that overall the majority of ambient PM2.5 in our study was regional, implying that local air pollution control strategies alone may have limited influence on local ambient concentrations. We compared the relatively new moving average subtraction method against a more established approach. Both methods broadly agree on the relative contribution of local sources across the three sites. The moving average subtraction method has broad applicability across locations

    On attributes of a Rotating Neutron star with a Hyperon core

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    We study the effect of rotation on global properties of neutron star with a hyperon core in an effective chiral model with varying nucleon effective mass within a mean field approach. The resulting gross properties of the rotating compact star sequences are then compared and analyzed with other theoretical predictions and observations from neutron stars. The maximum mass of the compact star predicted by the model lies in the range (1.42.4) M(1.4-2.4) ~M_{\odot} at Kepler frequency ΩK\Omega_K, which is consistant with recent observation of high mass stars thereby reflecting the sensitivity of the underlying nucleon effective mass in the dense matter EoS. We also discuss the implications of the experimental constraints from the flow data from heavy-ion collisions on the global properties of the rotating neutron stars.Comment: 11 Pages, 10 Figures and 2 Table
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