Biochemical Alteration in the Labeo rohita Tissues Following Exposure to the Effluent Generated during Extraction of Metals from Polymetallic Sea Nodules          下载免费PDF全文

Huma Vaseem  Tarun K. Banerjee 《洁净——土壤、空气、水》2014,42(8):1060-1065

  相似文献   

Evaluation of energy balance closure adjustment methods by independent evapotranspiration estimates from lysimeters and hydrological simulations          下载免费PDF全文

Matthias Mauder  Sandra Genzel  Jin Fu  Ralf Kiese  Mohsen Soltani  Rainer Steinbrecher  Matthias Zeeman  Tirtha Banerjee  Frederik De Roo  Harald Kunstmann 《水文研究》2018,32(1):39-50

Non‐closure of the surface energy balance is a frequently observed phenomenon of hydrometeorological field measurements, when using the eddy‐covariance method, which can be ascribed to an underestimation of the turbulent fluxes. Several approaches have been proposed in order to adjust the measured fluxes for this apparent systematic error. However, there are uncertainties about partitioning of the energy balance residual between the sensible and latent heat flux and whether such a correction should be applied on 30‐min data or longer time scales. The data for this study originate from two grassland sites in southern Germany, where measurements from weighable lysimeters are available as reference. The adjusted evapotranspiration rates are also compared with joint energy and water balance simulations using a physically based distributed hydrological model. We evaluate two adjustment methods: the first one preserves the Bowen ratio and the correction factor is determined on a daily basis. The second one attributes a smaller portion of the residual energy to the latent heat flux than to the sensible heat flux for closing the energy balance for every 30‐min flux integration interval. Both methods lead to an improved agreement of the eddy‐covariance based fluxes with the independent lysimeter estimates and the physically based model simulations. The first method results in a better comparability of evapotranspiration rates, and the second method leads to a smaller overall bias. These results are similar between both sites despite considerable differences in terrain complexity and grassland management. Moreover, we found that a daily adjustment factor leads to less scatter than a complete partitioning of the residual for every half‐hour time interval. The vertical temperature gradient in the surface layer and friction velocity were identified as important predictors for a potential future parameterisation of the energy balance residual.  相似文献   

Stochastic dynamic analysis of a historical masonry bridge under surface blast-induced multi-point ground motion     

Kemal Hacıefendioğlu  Swagata Banerjee  Kurtuluş Soyluk  Emre Alpaslan 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(5):1275-1286

  相似文献   

Basaltic glass as a habitat for microbial life: Implications for astrobiology and planetary exploration     

M.R.M. Izawa  N.R. Banerjee  N.J. Bridge 《Planetary and Space Science》2010,58(4):583-710

Recent studies have demonstrated that terrestrial subaqueous basalts and hyaloclastites are suitable microbial habitats. During subaqueous basaltic volcanism, glass is produced by the quenching of basaltic magma upon contact with water. On Earth, microbes rapidly begin colonizing the glassy surfaces along fractures and cracks that have been exposed to water. Microbial colonization of basaltic glass leads to the alteration and modification of the rocks and produces characteristic granular and/or tubular bioalteration textures. Infilling of the alteration textures by minerals such as phyllosilicates, zeolites and titanite may enable their preservation through geologic time. Basaltic rocks are a major component of the Martian crust and are widespread on other solar system bodies. A variety of lines of evidence strongly suggests the long-term existence of abundant liquid water on ancient Mars. Recent orbiter, lander and rover missions have found evidence for the presence of transient liquid water on Mars, perhaps persisting to the present day. Many other solar system bodies, notably Europa, Enceladus and other icy satellites, may contain (or have once hosted) subaqueous basaltic glasses. The record of terrestrial glass bioalteration has been interpreted to extend as far back as ∼3.5 billion years ago and is widespread in oceanic crust and its metamorphic equivalents. The terrestrial record of glass bioalteration strongly suggests that glassy or formerly glassy basaltic rocks on extraterrestrial bodies that have interacted with liquid water are high-value targets for astrobiological exploration.  相似文献   

Early Miocene shell concentration in the mixed carbonate-siliciclastic system of Kutch and their distribution in sequence stratigraphic framework     

Pramod Kumar  Pratul Kumar Saraswati  Santanu Banerjee 《Journal of the Geological Society of India》2009,74(4):432-444

The Early Miocene succession of Kutch represents a mixed carbonate-siliciclastic depositional system. The carbonate part of the succession, characterized by high abundance of shallow marine benthic fauna, hosts typical shell concentrations (also referred as shell beds). The thickness of shell concentrations vary in scale from 5 cm to 100 cm and are separated by poorly fossiliferous to barren silty shales/siltstones. Based on taphonomic and sedimentological observations, shell concentrations are classified as lag, event, composite/multi-event and hiatal types. The occurrence of different types of shell concentrations in the background of sequence stratigraphic framework is the main theme for the present study. Overall, the shell concentrations occupy the middle part of the sequence i.e. upper part of the transgressive systems tract and lower part of the highstand systems tract. Lag concentrations are found in the lower part of the sequence while composite concentrations, the major contributors in the sequence, occur in upper part of the transgressive systems tract and in the lower part of the highstand systems tract. The hiatal concentrations are associated with maximum flooding surface while the position of event concentrations is independent of sequence stratigraphic framework. The shell concentrations occupy marine flooding surface or marine ravinement surface, thus mark parasequence boundaries.  相似文献   

Near-infrared and optical studies of the fast nova V4643 Sgr (Nova Sagittarii 2001)     

N. M. Ashok  D. P. K. Banerjee  W. P. Varricatt  U. S. Kamath 《Monthly notices of the Royal Astronomical Society》2006,368(2):592-598

It is generally accepted that the presence of a hot magnetic corona provides the source of X-ray emission in cool stars. With this connection one could expect to see the variation of magnetic flux in the activity cycle of a star mirrored by a similar variation in the stars X-ray emission. Using magnetic maps produced from flux emergence and transport simulations and assuming a potential field for the corona, we can extrapolate the coronal magnetic field and hence calculate the variation of the X-ray emission. We consider three types of activity cycle that successfully reproduce the pattern of intermingled magnetic flux at high latitudes, a feature observed with Zeeman–Doppler imaging. The three different cycles take the form of (1) an enhanced butterfly pattern where flux emergence is extended to a latitude of 70°, (2) an extended emergence profile as before but with an overlap of 4 yr in the butterfly diagram and (3) where no butterfly diagram is used. The cyclic variation in the X-ray emission is around two orders of magnitude for cases (1) and (3), but less than one order of magnitude for case (2). For all three cases, the rotational modulation of the X-ray emission is greatest at cycle minimum, but the emission measure weighted density varies little over the cycle. For cases (1) and (2) the fraction of the total flux that is open (along which a wind can escape) varies little over the cycle, but for case (3) this is three times larger at cycle minimum than at maximum. Our results clearly show that although magnetic cycles may exist for stars they are not necessarily observable in the X-ray emission.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987114000371     

Amlan Banerjee 《地学前缘(英文版)》2015,6(2):277-284

Dissolution of fluorite(CaF_2) and/or fluorapatite(FAP)[Ca_5(PO_4)_3F],pulled by calcite precipitation,is thought to be the dominant mechanism responsible for groundwater fluoride(F~-) contamination.Here,one dimensional reactive—transport models are developed to test this mechanism using the published dissolution and precipitation rate kinetics for the mineral pair FAP and calcite.Simulation results correctly show positive correlation between the aqueous concentrations of F and CO_3~(2-) and negative correlation between F~- and Ca~(2+).Results also show that precipitation of calcite,contrary to the present understanding,slows down the FAP dissolution by 10~6 orders of magnitude compared to the FAP dissolution by hydrolysis.For appreciable amount of fluoride contamination rock-water interaction time must be long and of order 10~6 years.  相似文献   

Simultaneous Longitudinal and Transverse Oscillations in an Active-Region Filament     

Vaibhav Pant  Rakesh Mazumder  Ding Yuan  Dipankar Banerjee  Abhishek K. Srivastava  Yuandeng Shen 《Solar physics》2016,291(11):3303-3315

  相似文献   

MODIS-FIRMS and ground-truthing-based wildfire likelihood mapping of Sikkim Himalaya using machine learning algorithms     

Banerjee  Polash 《Natural Hazards》2022,110(2):899-935

Natural Hazards - Wildfires in limited extent and intensity can be a boon for the forest ecosystem. However, recent episodes of wildfires of 2019 in Australia and Brazil are sad reminders of their...  相似文献   

Velocity shear effect on the longitudinal wave in a strongly coupled dusty plasma     

S. Garai  D. Banerjee  M. S. Janaki  N. Chakrabarti 《Astrophysics and Space Science》2014,349(2):789-798

The characteristics of longitudinal dust acoustic wave (DAW) in presence of velocity shear have been investigated in a strongly coupled dusty plasma using the generalized hydrodynamic (GH) model. In the hydrodynamic regime (ωτ _m ?1), i.e. when characteristic time τ _m is slower than inverse of wave frequency, the viscosity in the GH model plays the usual role of wave damping, whereas in the kinetic regime (ωτ _m ?1), i.e. when characteristic time τ _m is larger than inverse of wave frequency, viscosity shows energy storing property in the wave. In the kinetic regime, we have studied the longitudinal mode $\omega^{2}=k^{2} (c_{d}^{2}+c_{l}^{2})$ (where ω is the frequency, k is the wave number, c _d is the dust acoustic velocity and c _l is the longitudinal velocity that arises due to viscosity) in presence of velocity shear. It is shown that velocity shear can destabilize this mode. Both nonmodal and modal techniques are employed to demonstrate the growth rate of the instability.  相似文献