Adsorption of Cadmium from Aqueous Solution by Ficus religiosa Leaf Powder and Characterization of Loaded Biosorbent     

Karanam Srinivasa Rao  Shashi Anand  Paladugu Venkateswarlu 《洁净——土壤、空气、水》2011,39(4):384-391

The present investigation evaluates the adsorption effectiveness of Cd(II) ions on Ficus religiosa leaf powder (FRL). The experimental parameters chosen included time, pH, particle size, temperature, adsorbate, anion, and Pb(II) concentrations. The time data followed pseudo‐second‐order kinetics. Cd(II) adsorption increased from 1.38 to 75.17% with the increase in pH from 2 to 4 and further increase in pH to 5.5 resulted in its marginal increase to 77.52%. Based on regression coefficient values, the isothermic data fitted the various models in the order Langmuir > Redlich–Peterson > Temkin > Freundlich model. The maximum loading capacity of FRL was estimated to be 27.14 mg g^?1. The presence of Cl^?, , or Pb²⁺ exhibited adverse effect on Cd(II) uptake. The thermodynamic parameters of enthalpy (ΔH⁰) and entropy (ΔS⁰) were estimated to be 8.31 kJ mol^?1 and 38.22 J mol^?1 K^?1, respectively. SEM‐EPMA of the loaded FRL showed Cd(II) distribution at specific sites. The XRD patterns of Cd(II) loaded FRL sample showed disappearance of some peaks corresponding to β‐Ca(PO₃)₂; shifting of peaks and decrease in %RI corresponding to γ‐CaSO₄ phase. Positive shift of IR bands for the Cd(II) loaded sample was observed.  相似文献   

Resolution of multiple sheet-type structures in self-potential measurement     

Arkoprovo Biswas  Shashi Prakash Sharma 《Journal of Earth System Science》2014,123(4):809-825

The resolution of self-potential anomalies due to closely spaced multiple sheet-like bodies by the potential difference and potential gradient is studied in this paper. Self-potential anomalies due to several synthetic models were inverted through a very fast simulated annealing (VFSA) global optimization. Increase in depth to the top, polarization constant and depth extent of the body decreases resolution at a particular target separation. It has been observed that depth to the top and separation between two targets play an important role in the resolution. Vertical sheets at equal depth can be resolved in the potential difference measurement only if they are separated by at least four times their depth, while they can be resolved in the gradient method, if they are separated by twice the depth. Resolution using potential difference becomes more difficult for dipping sheets, although the potential gradient method can resolve them efficiently. Efficacy of potential gradient data in the inversion is demonstrated in the study using synthetic data as well as field measurement from South Purulia Shear Zone related with uranium investigation.  相似文献   

Further empirical evidence for the non-linearity of the period–luminosity relations as seen in the Large Magellanic Cloud Cepheids     

Chow-Choong Ngeow  Shashi M. Kanbur  Sergei Nikolaev  John Buonaccorsi  Kem H. Cook  Douglas L. Welch 《Monthly notices of the Royal Astronomical Society》2005,363(3):831-846

Recent studies, using OGLE data for LMC Cepheids in the optical, strongly suggest that the period–luminosity (PL) relation for the Large Magellanic Cloud (LMC) Cepheids shows a break or non-linearity at a period of 10 d. In this paper we apply statistical tests, the chi-squared test and the F -test, to the Cepheid data from the MACHO project to test for a non-linearity of the V - and R -band PL relations at 10 d, and extend these tests to the near-infrared ( JHK -band) PL relations with 2MASS data. We correct the extinction for these data by applying an extinction map towards the LMC. The statistical test we use, the F -test, is able to take account of small numbers of data points and the nature of that data on either side of the period cut at 10 d. With our data, the results we obtained imply that the VRJH -band PL relations are non-linear around a period of 10 d, while the K -band PL relation is (marginally) consistent with a single-line regression. The choice of a period of 10 d, around which this non-linearity occurs, is consistent with the results obtained when this 'break' period is estimated from the data. We show that robust parametric (including least-squares, least absolute deviation, robust regression) and non-parametric regression methods, which restrict the influence of outliers, produce similar results. Long-period Cepheids are supplemented from the literature to increase our sample size. The photometry of these long-period Cepheids is compared with our data and no trend with period is found. Our main results remain unchanged when we supplement our data set with these long-period Cepheids. By examining our data at maximum light, we also suggest arguments as to why errors in reddening are unlikely to be responsible for our results. The non-linearity of the mean V -band PL relation as seen in both of the OGLE and the MACHO data, using different extinction maps, suggests that this non-linearity is real.  相似文献   

Period–colour and amplitude–colour relations in classical Cepheid variables – IV. The multiphase relations     

Chow-Choong Ngeow  Shashi M. Kanbur 《Monthly notices of the Royal Astronomical Society》2006,369(2):723-733

The superb phase resolution and quality of the Optical Gravitational Lensing Experiment (OGLE) data on the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) Cepheids, together with existing data on Galactic Cepheids, are combined to study the period–colour (PC) and amplitude–colour (AC) relations as a function of pulsation phase. Our results confirm earlier work that the LMC PC relation (at mean light) is more consistent with two lines of differing slopes, separated at a period of 10 d. However, our multiphase PC relations reveal much new structure which can potentially increase our understanding of Cepheid variables. These multiphase PC relations provide insight into why the Galactic PC relation is linear but the LMC PC relation is non-linear. This is because the LMC PC relation is shallower for short  (log  P < 1)  and steeper for long  (log  P > 1)  period Cepheids than the corresponding Galactic PC relation. Both of the short- and long-period Cepheids in all three galaxies exhibit the steepest and shallowest slopes at phases around 0.75–0.85, respectively. A consequence is that the PC relation at phase ∼ 0.8 is highly non-linear. Further, the Galactic and LMC Cepheids with  log  P > 1  display a flat slope in the PC plane at phases close to the maximum light. When the LMC period–luminosity (PL) relation is studied as a function of phase, we confirm that it changes with the PC relation. The LMC PL relation in V and I band near the phase of 0.8 provides compelling evidence that this relation is also consistent with two lines of differing slopes joined at a period close to 10 d.  相似文献   

The impact of using area-averaged land surface properties —topography, vegetation condition, soil wetness—in calculations of intermediate scale (approximately 10 km) surface-atmosphere heat and moisture fluxes     

Piers J. Sellers  Mark D. Heiser  Forrest G. Hall  Shashi B. Verma  Raymond L. Desjardins  Peter M. Schuepp  J. Ian MacPherson 《Journal of Hydrology》1997,190(3-4):269-301

It is commonly assumed that biophysically based soil-vegetation-atmosphere transfer (SVAT) models are scale-invariant with respect to the initial boundary conditions of topography, vegetation condition and soil moisture. In practice, SVAT models that have been developed and tested at the local scale (a few meters or a few tens of meters) are applied almost unmodified within general circulation models (GCMs) of the atmosphere, which have grid areas of 50–500 km². This study, which draws much of its substantive material from the papers of Sellers et al. (1992c, J. Geophys. Res., 97(D17): 19033–19060) and Sellers et al. (1995, J. Geophys. Res., 100(D12): 25607–25629), explores the validity of doing this. The work makes use of the FIFE-89 data set which was collected over a 2 km × 15 km grassland area in Kansas. The site was characterized by high variability in soil moisture and vegetation condition during the late growing season of 1989. The area also has moderate topography.

The 2 km × 15 km ‘testbed’ area was divided into 68 × 501 pixels of 30 m × 30 m spatial resolution, each of which could be assigned topographic, vegetation condition and soil moisture parameters from satellite and in situ observations gathered in FIFE-89. One or more of these surface fields was area-averaged in a series of simulation runs to determine the impact of using large-area means of these initial or boundary conditions on the area-integrated (aggregated) surface fluxes. The results of the study can be summarized as follows:

1. 1. analyses and some of the simulations indicated that the relationships describing the effects of moderate topography on the surface radiation budget are near-linear and thus largely scale-invariant. The relationships linking the simple ratio vegetation index (SR), the canopy conductance parameter (_F) and the canopy transpiration flux are also near-linear and similarly scale-invariant to first order. Because of this, it appears that simple area-averaging operations can be applied to these fields with relatively little impact on the calculated surface heat flux.

2. 2. The relationships linking surface and root-zone soil wetness to the soil surface and canopy transpiration rates are non-linear. However, simulation results and observations indicate that soil moisture variability decreases significantly as an area dries out, which partially cancels out the effects of these non-linear functions.In conclusion, it appears that simple averages of topographic slope and vegetation parameters can be used to calculate surface energy and heat fluxes over a wide range of spatial scales, from a few meters up to many kilometers at least for grassland sites and areas with moderate topography. Although the relationships between soil moisture and evapotranspiration are non-linear for intermediate soil wetnesses, the dynamics of soil drying act to progressively reduce soil moisture variability and thus the impacts of these non-linearities on the area-averaged surface fluxes. These findings indicate that we may be able to use mean values of topography, vegetation condition and soil moisture to calculate the surface-atmosphere fluxes of energy, heat and moisture at larger length scales, to within an acceptable accuracy for climate modeling work. However, further tests over areas with different vegetation types, soils and more extreme topography are required to improve our confidence in this approach.

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Genesis of Coal Metamorphism of Late PalaeozoicCoals in the South of North China——A Further Approach to the Effects of ThermalGroundwater on Coal Metamorphism     

Zhong NingningJianghan Petroleum Institute  Shashi City  Hubei  Cao DaiyongBeijing Graduate School  China University of Mining  Technology  Beijing Jiang Minxi 《《地质学报》英文版》1995,69(2):183-195

The close relationship between the genesis of coal metamorphism and the evolution of the regional tectonic framework is expounded on the basis of an analysis of the geological factors causing the metamorphic zonation of the Late Palaeozoic coals in southern North China; in terms of the mechanism for the formation of palaeogeothermal anomalies, the effects of thermal groundwater on coal metamorphism is highlighted and a geological model for thermal groundwater metamorphism of coal established; with the concept of the palaeogeotherm-coal metamorphism system, the genesis of coal metamorphism is analysed according to the distribution pattern of three geological factors: heat source, heat-carrier and channel, and heat-collector.  相似文献   

Can very low frequency electromagnetic survey detect graphite deposits in the subsurface? Initial results from Daltanganj,Jharkhand     

Arkoprovo Biswas  Shashi Prakash Sharma 《Journal of the Geological Society of India》2015,86(5):530-534

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Influence of scattering of SH-waves in dynamic interaction of shear wall with soil layers     

Kumar  Shashi  Chakraborty  Swapan Kumar 《地震工程与工程振动(英文版)》2020,19(3):583-595

The dynamic soil-structure interaction of a shear wall embedded in elastic isotropic and homogeneous soil layers underlain by bedrock, subjected to SH waves, is modeled in the present article. The soil layers consist of irregular interfaces and it has been shown that the scattering due to the roughness of the layers has significant effect on the displacement of both the foundation and the shear wall. To demonstrate the phenomena indirect boundary element method(IBEM) has been used on the basis of its validation in previous problems of similar type. The system response is compared with the analytical solution of the same type of model for vertically propagating incident SH waves. It is observed that for the low frequency of wave, displacement is abruptly high, and as a result the combination of shear wall and foundation perceives resonance. The thickness of the soil layer, mass of the shear wall, stiffness of the bedrock and the soil layers all affects the system frequency and displacement.  相似文献   

Ecological variables influencing the diversity and distribution of macrolichens colonizing Quercus leucotrichophora in Uttarakhand forest     

Shashi UPADHYAY  Arun K.JUGRAN  Yogesh JOSHI  Renu SUYAL  Ranbeer S.RAWAL 《山地科学学报》2018,(2)

Ecological variables play a significant role in determining the diversity and distribution of any living organism on earth. Lichens are not exceptional and are quite sensitive in comparison to other organisms; hence the present study focuses on the impact of ecological variables on the diversity and distribution of epiphytic macrolichens colonizing Quercus leucotrichophora across eight different sites(50 m × 50 m) in Thal Ke Dhar forest, Kumaun Himalaya, Uttarakhand, India. For sampling of macrolichens, 200 trees(25 trees from each site) of Q.leucotrichophora were selected from each site and five quadrats of 5 cm × 10 cm(1000 quadrats in totality) were drawn at the tree trunk. From all the sampled trees, a total of 54 species of epiphytic macrolichens belonging to 18 genera and five families were recorded. Various ecological variables, namely altitude, aspect, slope, diameter at breast height(DBH), and lopping percent(partial cutting of the twigs as disturbance), were also analyzed to investigate their influence on macrolichen species composition and distribution pattern in the study area. For the determination of relationships between these variables, statistical analysis, namely Pearson's Correlation Coefficient, Polynomial regression analysis and Principal Component Analysis(PCA)were performed. Out of all variables, lopping was significantly correlated to species richness of epiphytic macrolichens(0.712~*, p0.05) and it was confirmed by Pearson's Correlation Coefficient.Despite of having high anthropogenic pressure or impact through lopping, the maximum number of macrolichen species was recorded at elevation 2267 meter above sea level(m asl). The present study revealed that besides other ecological variables,lopping practices can act as a key parameter incontrolling the diversity and distribution not only of epiphytic macrolichens but also of other life forms such as bryophytes, pteridophytes, insects, birds etc.and can be either negatively or positively correlated.  相似文献   

Laterite covered mafic-ultramafic rocks: Potential target for chromite exploration–A case study from southern part of Tangarparha,Odisha     

Animesh Mandal  William K. Mohanty  Shashi Prakash Sharma  Saibal Gupta 《Journal of the Geological Society of India》2015,86(5):519-529

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