Three-dimensional hydrodynamic simulations of asymmetric pulsar wind bow shocks     

M. Vigelius  A. Melatos  S. Chatterjee †  B. M. Gaensler ‡§  P. Ghavamian 《Monthly notices of the Royal Astronomical Society》2007,374(3):793-808

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Changes in Ellipticals Due to Collisions with Spirals and Their Consequences     

T. K. Chatterjee  V. B. Magalinsky 《Astrophysics》2001,44(3):315-320

A study of collisions between spiral and elliptical galaxies (approximated as composite spherical masses) is made to assess the changes undergone by the elliptical. Results indicate that unless the spiral is extremely massive compared to the elliptical, the elliptical is almost unaffected, while the spiral is strongly affected. For the frequent type of collision between equally massive spiral and elliptical galaxies, the elliptical is negligibly affected, while disruptive effects set in the spiral. However, the stellar pattern of the elliptical is changed and the stars are found to crowd in faint shells after the collision. The consequences of these results are explored in the context of the morphology-density relationship and the elliptical companions of ring galaxies.  相似文献   

Biosorption of Cadmium(II) Ions by Citrus Peels in a Packed Bed Column: Effect of Process Parameters and Comparison of Different Breakthrough Curve Models     

Abhijit Chatterjee  Silke Schiewer 《洁净——土壤、空气、水》2011,39(9):874-881

The efficiency of low cost citrus peels as biosorbents for removal of cadmium ions from aqueous solution was investigated in a fixed bed column, a process that could be applied to treat industrial wastewaters similar to commonly used ion exchange columns. Effluent concentration versus time profiles (i.e., breakthrough curves) were experimentally determined in a laboratory‐scale packed bed column for varying operational parameters such as flow rate (2, 9, and 15.5 mL/min), influent cadmium concentration (5, 10, and 15 mg/L), and bed height (24, 48, and 72 cm) at pH 5.5. Column operation was most efficient for empty bed contact times of at least 10 min, which were apparently necessary for mass transfer. While the sorption capacity was largely unaffected by operational variables, the Thomas (Th) rate constant increased with the flow rate, and slightly decreased with increasing column length. Three widely used semi‐mechanistic models (Th, Bohart–Adams, and Yoon–Nelson) were shown to be equivalent and the generalized model was compared with a two‐parameter empirical model (dose‐response). The latter was found to be able to better simulate the breakthrough curve in the region of breakthrough and saturation.  相似文献   

Evaluation of crustal and upper mantle structures using receiver function analysis: ISM broadband observatory data     

J. R. Kayal  V. K. Srivastava  P. Kumar  Rima Chatterjee  P. K. Khan 《Journal of the Geological Society of India》2011,78(1):76-80

A three-component broadband seismograph is in operation since January 2007 at the Indian School of Mines (ISM) campus, Dhanbad. We have used the broadband (BB) seismograms of 17 teleseismic events (M ≥ 5.8) recorded by this single BB station during 2008–09 to estimate the crust and upper mantle discontinuities in Dhanbad area which falls in the peninsular India shield. The converted wave technique and the Receiver function analysis are used. A 1-D velocity model has been derived using inversion. The Mohorovicic (Moho) discontinuity (crustal thickness) below the ISM observatory is estimated to be ∼41 km, with an average Poisson ratio of ∼0.28, suggesting that the crust below the Dhanbad area is intermediate to mafic in nature. The single station BB data shed new light to the estimate of crustal thickness beneath the eastern India shield area, which was hitherto elusive. Further, it is observed that the global upper mantle discontinuity at 410 km is delayed by ∼0.6 sec compared to the IASP-91 global model; this may be explained by a slower/hotter upper mantle; while the 660 km discontinuity is within the noise level of data.  相似文献   

Determination of in-situ stress direction from cleat orientation mapping for coal bed methane exploration in south-eastern part of Jharia coalfield, India     

Suman Paul Rima Chatterjee 《International Journal of Coal Geology》2011,87(2):87-96

Accurate prediction of in-situ stress directions plays a key role in any Coal Bed Methane (CBM) exploration and exploitation project in order to estimate the production potential of the CBM reservoirs. Permeability is one of the most important factors for determination of CBM productivity. The coal seams in Jharia coalfield generally show low permeability in the range of 0.5 md to 3 md. To estimate the in-situ stress direction in the study area, an attempt has been made to undertake the cleat orientation mapping of four regional coal seams of two underground coal mines located at south-eastern part of Jharia coalfield, India. Cleat orientation mapping is critical to determine the maximum principal compressive horizontal stress (S_H) direction for CBM exploration and exploitation, which in turn controls the direction of maximum gas or water flow though coal beds. From the field study it is found that the average face and butt cleat azimuths are towards N15°W and N75°E respectively. Average permeability of the four above-mentioned major coal seams has been calculated from well logs of nine CBM wells distributing over an area of 7.5 km², adjacent to the underground mines. The cleat orientations are congruous with the regional lineament pattern and fits well with the average permeability contour map of the study area to infer the orientation of in-situ maximum horizontal stress. Goodness of fit for the exponential regressions between vertical stress and permeability for individual coal seams varies between 0.6 and 0.84. The cleat orientation is further validated from the previous fracture analysis using FMI well log in Parbatpur area located southern part of the Jharia coalfield. The major coal seams under the study area exhibit directional permeability, with the maximum permeability, oriented parallel to the direction of face cleat orientation.  相似文献   

Zircon evaporation ages and geochemistry of metamorphosed volcanic rocks from the Vinjamuru domain,Krishna Province: evidence for 1.78 Ga convergent tectonics along the southeastern margin of the Eastern Dharwar Craton     

Ravikant Vadlamani  A. Krner  D. Vasudevan  I. Wendt  H. Tobschall  C. Chatterjee 《Geological Journal》2013,48(4):293-309

Palaeoproterozoic intermediate to potassic felsic volcanism in volcano‐sedimentary sequences could either have occurred in continental rift or at convergent magmatic arc tectonic settings. The Vinjamuru domain of the Krishna Province in Andhra Pradesh, SE India, contains such felsic and intermediate metavolcanic rocks, whose geochemistry constrains their probable tectonic setting and which were dated by the zircon Pb evaporation method in order to constrain their time of formation. These rocks consist of interlayered quartz–garnet–biotite schist, quartz–hematite–baryte–sericite schist as well as cherty quartzite, and represent a calc‐alkaline volcanic sequence of andesitic to rhyolitic rocks that underwent amphibolite‐facies metamorphism at ~1.61 Ga. Zircons from four felsic metavolcanic rock samples yielded youngest mean ²⁰⁷Pb/²⁰⁶Pb ages between 1771 and 1791 Ma, whereas the youngest zircon age for a meta‐andesite is 1868 Ma. A ~2.43 Ga zircon xenocryst reflects incorporation of Neoarchaean basement gneisses. Their calc‐alkaline trends, higher LILE, enriched chondrite‐normalized LREE pattern and negative Nb and Ti anomalies on primitive mantle‐normalized diagrams, suggest formation in a continental magmatic arc tectonic setting. Whereas the intermediate rocks may have been derived from mantle‐source parental arc magmas by fractionation and crustal contamination, the rhyolitic rocks had crustal parental magmas. The Vinjamuru Palaeoproterozoic volcanic eruption implies an event of convergent tectonism at the southeastern margin of the Eastern Dharwar Craton at ~1.78 Ga forming one of the major crustal domains of the Krishna Province. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Bifurcations of dust ion acoustic travelling waves in a magnetized quantum dusty plasma     

Utpal Kumar Samanta  Asit Saha  Prasanta Chatterjee 《Astrophysics and Space Science》2013,347(2):293-298

Bifurcation behavior of nonlinear dust ion acoustic travelling waves in a magnetized quantum dusty plasma has been studied. Applying the reductive perturbation technique (RPT), we have derived a Kadomtsev-Petviashili (KP) equation for dust ion acoustic waves (DIAWs) in a magnetized quantum dusty plasma. By using the bifurcation theory of planar dynamical systems to the KP equation, we have proved that our model has solitary wave solutions and periodic travelling wave solutions. We have derived two exact explicit solutions of the above travelling waves depending on different parameters.  相似文献   

Planar and nonplanar ion acoustic shock waves with nonthermal electrons and positrons     

Prasanta Chatterjee  Deb Kumar Ghosh  Biswajit Sahu 《Astrophysics and Space Science》2012,339(2):261-267

The nonlinear propagation of ion acoustic shock waves (IASWs) are studied in an unmagnetized plasma consisting of nonthermal electrons, nonthermal positrons, and singly charged adiabatically hot positive ions, whose dynamics is governed by the two dimensional nonplanar Kadomstev-Petviashvili-Burgers (KPB) equation. The shock solution of the KPB equations is obtained numerically. The effects of several parameters and ion kinematic viscosities on the properties of ion acoustic shock waves are discussed in planar and nonplanar geometry. It is shown that the ion acoustic shock wave propagating in cylindrical/spherical geometry with transverse perturbation will be deformed as time goes on. Also, it is seen that the strength and the steepness of the IASWs increases with increasing β, the nonthermal parameter.  相似文献   

Superthermal effect of electrons on nonplanar dust-ion-acoustic solitary waves and double layers in a dusty plasma     

Uday Narayan Ghosh  Deb Kumar Ghosh  Prasanta Chatterjee  Biswajit Sahu 《Astrophysics and Space Science》2012,342(2):449-456

The basic features of planar and nonplanar time-dependent dust-ion-acoustic (DIA) solitary waves (SWs) and double layers (DLs) have been studied in an unmagnetized dusty plasma system consisting of positively and negatively charged dust, Boltzmann distributed ions and superthermal electrons (represented by kappa distribution). Using the reductive perturbation technique (RPT) we have derived modified Gardner (MG) equation, which gives information beyond the Korteweg-de Vries (KdV) limits (corresponding to the vanishing of nonlinear coefficient of the KdV equation). It is seen that the properties of nonplanar DIA SWs and DLs are significantly differs as the value of spectral index kappa (κ) changes. The present investigation may have relevance in the study of propagation of DIA waves in space and laboratory plasmas.  相似文献   

Correction to: Soliton and shocks in pair ion plasma in presence of superthermal electron     

Utpal Kumar Samanta  Prasanta Chatterjee  Monimala Nej 《Astrophysics and Space Science》2018,363(6):121

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