Theoretical modeling insights into elastic wave attenuation mechanisms in marine sediments with pore-filling methane hydrate

The majority of presently exploitable marine methane hydrate reservoirs are likely to host hydrate in disseminated form in coarse grain sediments. For hydrate concentrations below 25–40%, disseminated or pore-filling hydrate does not increase elastic frame moduli, thus making impotent traditional seismic velocity-based methods. Here, we present a theoretical model to calculate frequency-dependent P and S wave velocity and attenuation of an effective porous medium composed of solid mineral grains, methane hydrate, methane gas, and water. The model considers elastic wave energy losses caused by local viscous flow both (i) between fluid inclusions in hydrate and pores and (ii) between different aspect ratio pores (created when hydrate grows); the inertial motion of the frame with respect to the pore fluid (Biot's type fluid flow); and gas bubble damping. The sole presence of pore-filling hydrate in the sediment reduces the available porosity and intrinsic permeability of the sediment affecting Biot's type attenuation at high frequencies. Our model shows that attenuation maxima due to fluid inclusions in hydrate are possible over the entire frequency range of interest to exploration seismology (1–106 Hz), depending on the aspect ratio of the inclusions, whereas maxima due to different aspect ratio pores occur only at sonic to ultrasound frequencies (104–106 Hz). This frequency response imposes further constraints on possible hydrate saturations able to reproduce broadband elastic measurements of velocity and attenuation. Our results provide a physical basis for detecting the presence and amount of pore-filling hydrate in seafloor sediments using conventional seismic surveys

Pathology of mixed infections of saprolegniasis-myxosporidiosis in Indian major carp (Catla catla Ham.)

An outbreak of saprolegniasis in Catla catla in composite carp culture ponds were recorded during winter season. The typical cotton wool growths were observed on whole body surfaces of catla along with sporadic mortality. The fungal invasion was only restricted to skin and no fungal elements were visible in any internal organs after periodic acid schiff staining. On histology, periportal accumulation of mononuclear cells in liver, presence of myxosporidean cysts in antieror kidney, eosinophilic granular cells reaction in submucosa of stomach and intestine, dilated and engorged blood vessels of brain along with sloughing of epidermis and hyperplasia at gill lamellar base were pronounced changes. The possible role of release of Saprolegnia toxin in producing internal organs pathology has been discussed

Ethnobotanical study of medicinal plants in the coastal districts of Odisha

Ethnobotanical study was carried out in the coastal districts of Odisha during 2010-2011 to document the medicinal utility of plants. The present paper deals with traditional uses of 46 plant species belonging to 44 genera and 32 families along with correct botanical identification, local names, parts used and mode of administration in respect to different diseases.  The documented ethnomedicinal plants are mostly used to cure skin diseases, diarrhoea, jaundice, piles and urinary troubles

CFD Simulation to Optimise Single Stage Pulse Tube Refrigerator Temperature Below 6oK

AbstractAn optimize result of the single stage iterance tube pulse tube refrigerator (ITPTR) has been found by the use of a computational fluid dynamic (CFD) solution method. A well CFD solution software FLUENT is used for solution purpose. A number of case has been solved by changing the pulse tube length by taking diameter constant out of which it is found that a length of about 125mm at which the minimum temperature is achieved at cold heat exchanger end of 58K. The variation in any parameter of ITPTR will affect the cooling temperature that may be the length or diameter of pulse tube or inertance tube or change in operating frequency but it is essential to achieve lower temperature than till date achieved by same method. So for optimization purpose we take the length of pulse tube length as the varying Para-meter and the operating frequency 34Hz, pulse tube diameter 5mm remains constant. To get an optimum parameter experimentally is a very tedious for iterance tube pulse tube refrigerator job so the CFD approach gives a better solution which is the main purpose of the present work

Absorption cross section in warped AdS_3 black hole revisited

We investigate the absorption cross section for minimal-coupled scalars in the warped AdS_3 black hole. According to our calculation, the cross section reduces to the horizon area in the low energy limit as usually expected in contrast to what was previously found. We also calculate the greybody factor and find that the effective temperatures for the two chiral CFT's are consistent with that derived from the quasinormal modes. Observing the conjectured warped AdS/CFT correspondence, we suspect that a specific sector of the CFT operators with the desired conformal dimension could be responsible for the peculiar thermal behaviour of the warped AdS_3 black hole.Comment: 16+1 pages, typos corrected, references and footnotes adde

Active power regulation of hydro dominating energy system using IDD optimized FPA

In this paper an attempt is made to propose the different models of control and design such as integral derivative (ID), proportional integral derivative (PID) and integral double derivative (IDD) effectively optimized through flower pollination algorithm (FPA) for active power regulation of modern energy system having hydro dominating areas. At first, the performance of FPA-ID, FPA-PID and FPA-IDD founded LFC are evaluated for standard load change in one control area and their performance for system model is judged on the basis of inverse time multiplied absolute error (ITAE). The results obtained show the advancement of FPA-IDD over other designs for hydro dominating energy system. The performance of the control lacks in minimizing system overshoot, oscillations and settling time due to large responding time of hydro turbines. Hence, the collective operation of unified power flow control (UPFC) in series with tie-line and active power support from redox flow battery is installed in the hydro dominating energy system. The significant improvement in system results are obtained by installing the UPFC and RFB in system model. Further enhancement in the system results are achieved by recalculating the gains of IDD with the help of FPA with positive support from RFB and UPFC. The application results are obtained for standard load change and results show the effectiveness of the proposed technique for the hydro dominating energy system.10th International Conference on Applied Energy (ICAE2018), 22-25 August 2018, Hong Kong, Chinahttp://www.elsevier.com/locate/procediaam2020Electrical, Electronic and Computer Engineerin

Linear Stability of Triangular Equilibrium Points in the Generalized Photogravitational Restricted Three Body Problem with Poynting-Robertson Drag

In this paper we have examined the linear stability of triangular equilibrium points in the generalised photogravitational restricted three body problem with Poynting-Robertson drag. We have found the position of triangular equilibrium points of our problem. The problem is generalised in the sense that smaller primary is supposed to be an oblate spheroid. The bigger primary is considered as radiating. The equations of motion are affected by radiation pressure force, oblateness and P-R drag. All classical results involving photogravitational and oblateness in restricted three body problem may be verified from this result. With the help of characteristic equation, we discussed the stability. Finally we conclude that triangular equilibrium points are unstable.Comment: accepted for publication in Journal of Dynamical Systems & Geometric Theories Vol. 4, Number 1 (2006

The STAR Photon Multiplicity Detector

Details concerning the design, fabrication and performance of STAR Photon Multiplicity Detector (PMD) are presented. The PMD will cover the forward region, within the pseudorapidity range 2.3--3.5, behind the forward time projection chamber. It will measure the spatial distribution of photons in order to study collective flow, fluctuation and chiral symmetry restoration.Comment: 15 pages, including 11 figures; to appear in a special NIM volume dedicated to the accelerator and detectors at RHI

Modelling and Prediction of Soil Organic Carbon using Digital Soil Mapping in the Thar Desert Region of India

Not AvailableIn the present study, the distribution of soil organic carbon (SOC) was investigated using digital soil mapping for an area of ~29 lakhs ha in Bikaner district, Rajasthan, India. To achieve this goal, 187 soil profiles were used for SOC estimation by Quantile regression forest (QRF) model technique. Landsat data, terrain attributes and bioclimatic variables were used as environmental variables. 10-fold cross-validation was used to evaluate model. Equal-area quadratic splines were fitted to soil profile datasets to estimate SOC at six standard soil depths (0-5, 5-15, 15-30, 30-60, 60-100 and 100-200 cm). Results showed that the mean SOC concentration was very low with values varied from 1.18 to 1.53 g kg-1 in different depths. While predicting SOC at different depths, the model was able to capture low variability (R2 = 1–7%). Overall, the Lin’s concordance correlation coefficient (CCC) values ranged from 0.01 to 0.18, indicating poor agreement between the predicted and observed values. Root mean square error (RMSE) and mean error (ME) were 0.97 and 0.16, respectively. The values of prediction interval coverage probability (PICP) recorded 87.2–89.7% for SOC contents at different depths. The most important variables for predicting SOC concentration variations were the annual range of temperature, latitude, Landsat 8 bands 2, 5 and 6. Temperature-related variables and remote sensed data products are important for predicting SOC concentrations in arid regions. We anticipate that this digital information of SOC will be useful for frequent monitoring and assessment of carbon cycle in arid regions.Not Availabl

Measurement of the near-threshold e+e−→DDˉe^+e^- \to D \bar D cross section using initial-state radiation

We report measurements of the exclusive cross section for $e^+e^- \to D \bar D$, where $D=D^0$ or $D^+$, in the center-of-mass energy range from the $D \bar D$ threshold to $5\mathrm{GeV}/c^2$ with initial-state radiation. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of 673 $\mathrm{fb}^{-1}$.Comment: Presented at EPS07 and LP07 conferences, published in PRD(RC