Rhizofiltration of a Heavy Metal (Lead) Containing Wastewater Using the Wetland Plant Carex pendula     

Brijesh K. Yadav  Maarten A. Siebel  Johan J. A. van Bruggen 《洁净——土壤、空气、水》2011,39(5):467-474

Rhizofiltration is a subset technique of phytoremediation which refers to the approach of using plant biomass for removing contaminants, primarily toxic metals, from polluted water. The effective implementation of this in situ remediation technology requires experimental as well as conceptual insight of plant–water interactions that control the extraction of targeted metal from polluted water resources. Therefore, pot and simulation experiments are used in this study to investigate the rhizofiltration of a lead containing wastewater using plants of Carex pendula, a common wetland plant found in Europe. The metal contaminant extraction along with plant growth and water uptake rates from a wastewater having varying Pb concentration is studied experimentally for 2 wk. The temporal distribution of the metal concentration in the wastewater and the accumulated metal in different compartments of C. pendula at the end are analyzed using atomic absorption spectrometry. Parameters of the metal uptake kinetics are deduced experimentally for predicting the metal removal by root biomass. Further, mass balance equations coupled with the characterized metal uptake kinetics are used for simulating the metal partitioning from the wastewater to its accumulation in the plant biomass. The simulated metal content in wastewater and plant biomass is compared with the observed data showing a good agreement with the later. Results show that C. pendula accumulates considerable amounts of lead, particularly in root biomass, and can be considered for the cleanup of lead contaminated wastewaters in combination with proper biomass disposal alternatives. Also, the findings can be used for performing further non‐hydroponics experiment to mimic the real wetland conditions more closely.  相似文献   

Resonance in the earth-moon system around the sun including earth’s equatorial ellipticity     

Sushil Yadav  Rajiv Aggarwal 《Astrophysics and Space Science》2013,348(2):367-375

We have investigated the resonances in the earth-moon system around the sun including earth’s equatorial ellipticity. The resonance resulting from the commensurability between the mean motion of the moon and Γ (angle measured from the minor axis of the earth’s equatorial ellipse to the projection of the moon on the plane of the equator) is analyzed. The amplitude and the time period of the oscillation have been determined by using the procedure of Brown and Shook. We have shown the effects of Γ on the amplitude and the time period of the resonance oscillation using the data of the moon. It is observed that the amplitude decreases and the time period also decreases as Γ increases from 0^° to 45^°.  相似文献   

Intensity variation of cosmic rays near the heliospheric current sheet   总被引：1，自引：0，他引：1  

Badruddin R.S. Yadav  N.R. Vadav 《Planetary and Space Science》1985,33(2):191-201

Cosmic ray intensity variations near the heliospheric current sheet—both above and below it—have been studied during 1964–1976. Superposed epoch analysis of the cosmic ray neutron monitor data with respect to sector boundaries (i.e., heliospheric current sheet crossings) has been performed. In this analysis we have used the data from neutron monitors well distributed in latitude over the Earth's surface. First, this study has been made during the two solar activity minimum periods 1964–1965 and 1975–1976, using the data from Thule (cut-off rigidity 0 GV), Deep River (cut-off rigidity 1.02 GV), Rome (cut-off rigidity 6.32 GV) and Huancayo (cut-off rigidity 13.45 GV) neutron monitors. We have also analyzed the data from Deep River, Rome and Huancayo neutron monitors, for whom we have the data for full period (1964–1976), by dividing the periods according to the changes in solar activity, interplanetary magnetic field polarity and coronal holes. All these studies have shown a negative gradient with respect to heliomagnetic latitude (current sheet). These results have been discussed in the light of theoretical and observational evidences. Suggestions have been given to overcome the discrepancy between the observational and theoretical results. Further, possible explanations for these observational results have been suggested.  相似文献   

An experimental study of dissolution kinetics of Calcite, Dolomite, Leucogranite and Gneiss in buffered solutions at temperature 25 and 5°C   总被引：1，自引：0，他引：1  

S. K. Yadav  G. J. Chakrapani  M. K. Gupta 《Environmental Geology》2008,53(8):1683-1694

Laboratory experiments were carried out continuously for 30–35 days at 25 and 5°C in three different buffer solutions of pH 4.0, 2.2 and 8.4 to calculate dissolution rates of two minerals, calcite (CC) and dolomite (DM) and two rocks, leucogranite (LG) and gneiss (GN) from the Himalayan range. Calculated rates in terms of release of targeted elements versus time (Ca for CC; Mg for DM; Si for LG and GN) demonstrate direct correlation with temperature. Dissolution rates are higher at 25°C compared to 5°C. CC and DM were experimented only at pH 8.4 and results show that both undergo congruent dissolution with CC dissolving ∼5 times faster than DM. Ca and Mg exhibit average apparent activation energies (E _a) of 13.98 and 9.98 kcal mol⁻¹ respectively at pH 8.4 which reflects greater sensitivity of CC dissolution than DM dissolution towards an increase in temperature. Scanning Electron Microscope attached with Energy Dispersive X-Ray Analyser (SEM-EDX) data indicates that dissolution is controlled primarily by surface-reaction processes, with dislocation sites contributing maximum to the dissolution. As compared to CC and DM dissolution, LG and GN undergo relatively slower incongruent dissolution with precipitation of some secondary minerals as revealed from X-ray diffractometer (XRD) results. Rates of dissolution of LG is maximum at pH 2.2, moderate at pH 8.4 and least at pH 4.0, whereas GN shows maximum dissolution at pH 2.2, moderate at pH 4.0 and least at pH 8.4. A comparison in dissolution behavior of LG and GN at experimental conditions reveals that increase in Si-release rate in the temperature range between 5 and 25°C is maximum at pH 8.4 (∼3.4–4.5 times), moderate at pH 4.0 (∼3–1.8 times) and least at pH 2.2 (∼1.0–1.5 times). Within the experimental temperature range, calculated values of E _a for Si release during LG and GN dissolution advocates positive correlation with pH. A substantial decrease in initial values of Brunauer–Emmett–Teller (BET) surface area of DM, LG, and GN has been encountered at the end of the experiment, except for CC for which an increase is observed. The study clearly demonstrates the dissolution behavior of pure minerals and rocks under controlled conditions. The dissolution rates assume enormous significance for the release of trace elements from rocks/minerals to the reacting water.  相似文献   

Landslide Hazard Zonation using Remote Sensing and GIS: a case study of Dikrong river basin, Arunachal Pradesh, India   总被引：3，自引：0，他引：3  

Ashish Pandey  P. P. Dabral  V. M. Chowdary  N. K. Yadav 《Environmental Geology》2008,54(7):1517-1529

Landslides are among the most costly and damaging natural hazards in mountainous regions, triggered mainly under the influence of earthquakes and/or rainfall. In the present study, Landslide Hazard Zonation (LHZ) of Dikrong river basin of Arunachal Pradesh was carried out using Remote Sensing and Geographic Information System (GIS). Various thematic layers namely slope, photo-lineament buffer, thrust buffer, relative relief map, geology and land use / land cover map were generated using remote sensing data and GIS. The weighting-rating system based on the relative importance of various causative factors as derived from remotely sensed data and other thematic maps were used for the LHZ. The different classes of thematic layers were assigned the corresponding rating value as attribute information in the GIS and an “attribute map” was generated for each data layer. Each class within a thematic layer was assigned an ordinal rating from 0 to 9. Summation of these attribute maps were then multiplied by the corresponding weights to yield the Landslide Hazard Index (LHI) for each cell. Using trial and error method the weight-rating values have been re-adjusted. The LHI threshold values used were: 142, 165, 189 and 216. A LHZ map was prepared showing the five zones, namely “very low hazard”, “low hazard”, “moderate hazard”, “high hazard” and “very high hazard” by using the “slicing” operation.  相似文献   

Globalization and India’s international trade: does distance still matter?     

Yadav  Purva 《GeoJournal》2021,86(4):1927-1941

GeoJournal - This paper attempts to capture the missing ‘distance’ puzzle in the globalization process driven by trade flows. It is widely recognized that the growing global economic...  相似文献   

Estimation of site response functions for the central seismic gap of Himalaya,India     

Sharma  Anjali  Yadav  Renu  Kumar  Dinesh  Paul  Ajay  Teotia  S. S. 《Natural Hazards》2021,109(2):1899-1933

Natural Hazards - In the analysis of seismic hazards of a particular region, the site response functions play a significant role. Site response functions for the central seismic gap become more...  相似文献   

Fresnel zone plate telescopes for X-ray imaging I: experiments with a quasi-parallel beam     

Sandip K. Chakrabarti  S. Palit  D. Debnath  A. Nandi  V. Yadav  Ritabrata Sarkar 《Experimental Astronomy》2009,24(1-3):109-126

Combination of Fresnel Zone Plates (FZP) can make an excellent telescope for imaging in X-rays. We present here the results of our experiments with several pairs of tungsten made Fresnel Zone plates in presence of an X-ray source kept at a distance of about 45 ft. The quasi-parallel beam allowed us to study sources placed on the axis as well as off the axis of the telescope. We present theoretical study of the fringe patterns produced by the zone plates in presence of a quasi-parallel source. We compare the patterns obtained from experiments with those obtained by our Monte-Carlo simulations. The images are also reconstructed by deconvolution from both the patterns. We compare the performance of such a telescope with other X-ray imaging devices used in space-astronomy.  相似文献   

Mass balance and morphological evolution of the Dokriani Glacier,central Himalaya,India during 1999–2014     

Purushottam Kumar Garg  Jairam Singh Yadav  Santosh Kumar Rai  Aparna Shukla 《地学前缘(英文版)》2022,(1):255-267

Glaciological mass balance(MB)is considered the most direct,undelayed and unfiltered response of the glaciers to climatic perturbations.However,it may inherit errors associated with stake underrepresentation,averaging over the entire glacier and human bias.Therefore,proper validation of glaciological MB with geodetic MB is highly recommended by the World Glacier Monitoring Service(WGMS).The present study focuses on the Dokriani Glacier,central Himalaya which is one of the bench-mark glaciers in the region and has glaciological MB records from 1993 to 2013 with intermittent gaps.In the present study,firstly the glaciological MB series is extended to 2014 i.e.,field-based MB for one more year is computed and,to compare with it,the geodetic MB is computed for the 1999–2014 period using high resolution Cartosat-1 digital elevation model(DEM)and SRTM DEM.Finally,the study assesses the regional representation of the Dokriani Glacier in terms of MB and evaluates the influence of the MB regime on its morphological evolution.Results show that the average glaciological MB(-0.34±0.2 m water equivalent(w.e.)y-1)is more negative than the geodetic MB(-0.23±0.1 m w.e.y-1)for the 1999–2014 period.This is likely because of the partial representation of glacier margins in the glaciological MB,where melting is strikingly low owing to thick debris cover(>30 cm).In contrast,geodetic MB considers all marginal pixels leading to a comparatively low MB.A comparative assessment shows that the MB of Dokriani Glacier is less negative(possibly due to its huge accumulation area)than most other glacier-specific and regional MBs,restricting it to be a representative glacier in the region.Moreover,continuous negative MB has brought a peculiar change in the epiglacial morphology in the lower tongue of the glacier as differential debris thickness-induced differential melting has turned the glacier surface into a concave one.This concavity has led to development of a large(10–20 m deep)supraglacial channel which is expanding incessantly.The supraglacial channel is also connected with the snout wall and accelerates terminus disintegration.Given the total thickness of about 30–50 m in the lower glacier tongue,downwasting at its current pace,deepening/widening of supraglacial channel coupled with rapid terminus retreat may lead to the complete vanishing of the lower one km glacier tongue.  相似文献   

Inhomogeneous perfect fluid universe with electromagnetic field     

Anirudh Pradhan  Vineet K. Yadav  Lallan Yadav  A. K. Yadav 《Astrophysics and Space Science》2007,312(3-4):267-273

Cylindrically symmetric inhomogeneous cosmological model for perfect fluid distribution with electromagnetic field is obtained. The source of the magnetic field is due to an electric current produced along the z-axis. F ₁₂ is the non-vanishing component of electromagnetic field tensor. To get the deterministic solution, it has been assumed that the expansion θ in the model is proportional to the shear σ. Physical and geometric aspects of the models are also discussed in presence and absence of magnetic field.   相似文献