Toxicity of Diluted Dyeing and Printing Industry Effluent to a Penaeid Prawn,Parapenaeopsis sculptilis (Heller)     

Rahul Kundu  V. V. S. Prasad  A. P. Mansuri 《洁净——土壤、空气、水》1989,17(1):87-93

Experiments were carried out on the toxicity of diluted dyeing and printing industry effluent to a penaeid prawn, Parapenaeopsis sculptilis (Heller). Effluent tolerance experiments showed that both juvenile and adult prawns were unable to withstand the increasing concentration of the effluent. Juveniles were more susceptible to effluent than adults. As a consequence of higher consumption of energy due to the disturbed metabolism a decrease in the metabolite content was observed, whereas the content of ions showed an irregular trend with all the concentrations. The behavioural study showed that before death both juvenile and adult prawns became inactive, followed by paralysis. The physico-chemical nature of the effluent showed high amounts of solids, BOD, COD, sodium, magnesium, calcium, chloride, ammonium nitrogen, sulphate and absence of DO, probably causing an osmotic imbalance in the prawn body which leads to early mortality. Even a 1% concentration of such an effluent of a physico-chemical nature was reported to be toxic to the prawns.  相似文献   

Coccolithophores from the central Arabian Sea: Sediment trap results     

Lina P. Mergulhao  Rahul Mohan  V. S. N. Murty  M. V. S. Guptha  D. K. Sinha 《Journal of Earth System Science》2006,115(4):415-428

Sediment trap samples collected from a depth of 1018 m in the Central Arabian Sea Trap (CAST) at 14°28.2′N, 64°35.8′E were analyzed for temporal variation of coccolithophore fluxes from October 1993 to August 1994. Out of the twenty species of coccolithophores encountered,Gephyrocapsa oceanica, Emiliania huxleyi, Umbilicosphaera sibogae andUmbellosphaera irregularis were the most abundant. The total coccolithophore fluxes ranged from 28.5 × 10⁶m^-2d^-1 to 50.3 × 10⁶m^-2d^-1 showing seasonality with higher fluxes during the northeast (NE) monsoon and lower fluxes during the spring intermonsoon. The higher fluxes were attributed to the enhancement of primary production in the central Arabian Sea due to southward extent of nutrients from the northeast Arabian Sea by the prevailing surface currents. Similarly, the occurrences of relatively lower coccolithophore fluxes during the spring intermonsoon and southwest (SW) monsoon were attributed to the low nutrients in the warm, shallow surface mixed layer and downwelling to the south of Findlater Jet respectively in the central Arabian Sea. Some of the coccolithophore species such asE. huxleyi, G. oceanica, Calcidiscus leptoporus andUmbellosphaera tenuis showed signs of dissolution.  相似文献   

Correction to: Hydro-meteorological and agricultural trends in water-scarce Karha Basin,western India: current and future scenario     

Rahul S. Todmal  Mahendra S. Korade  Amit G. Dhorde  Rajendra B. Zolekar 《Arabian Journal of Geosciences》2018,11(12):317

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Genesis and simultaneous occurrences of the super cyclone Kyarr and extremely severe cyclone Maha in the Arabian Sea in October 2019     

Akhila  R. S.  Kuttippurath  J.  Rahul  R.  Chakraborty  A. 《Natural Hazards》2022,110(2):1133-1152

Natural Hazards - Waterlogging and sunlight shortage are important factors that significantly deteriorate the yield and quality of wheat. The objective of this study was to evaluate the effects of...  相似文献   

Hazardous area map: an approach of sustainable urban planning and industrial development—a review     

Ganguly  Madhurima  Aynyas  Rahul  Nandan  Abhishek  Mondal  Prasenjit 《Natural Hazards》2018,91(3):1385-1405

Natural Hazards - A hazard map is a map which shows about all the vulnerable regions present in any country or at any specific place or location which is affected or will be affected by natural...  相似文献   

Effects of primordial magnetic field on the formation rate of dark matter halos     

Varalakshmi Cheera  Rahul Nigam 《Astrophysics and Space Science》2018,363(5):93

We construct and demonstrate a method for computing the formation rate of the dark matter halo in the hierarchical model set up. This method uses the Press-Schecter distribution for the halos and hence applies only to the spherical halos. But this can be generalized to ellipsoidal structures also if one uses the Sheth-Torman distribution. After obtaining the formation rate, we study the effect of primordial magnetic field on the dynamics of these halos. We investigate the effect for different field strengths and conclude that a magnetic field stronger than 10 nG would impact the halos larger than \(10^{8}\) solar masses while a weaker field affects the formation rate of smaller halos.  相似文献   

Physical Properties of Umbral Dots Observed in Sunspots: A <Emphasis Type="Italic">Hinode</Emphasis> Observation     

Rahul Yadav  Shibu K. Mathew 《Solar physics》2018,293(4):54

Umbral dots (UDs) are small-scale bright features observed in the umbral part of sunspots and pores. It is well established that they are manifestations of magnetoconvection phenomena inside umbrae. We study the physical properties of UDs in different sunspots and their dependence on decay rate and filling factor. We have selected high-resolution, G-band continuum filtergrams of seven sunspots from Hinode to study their physical properties. We have also used Michelson Doppler Imager (MDI) continuum images to estimate the decay rate of selected sunspots. An identification and tracking algorithm was developed to identify the UDs in time sequences. The statistical analysis of UDs exhibits an averaged maximum intensity and effective diameter of 0.26 \(I_{\mathrm{QS}}\) and 270 km. Furthermore, the lifetime, horizontal speed, trajectory length, and displacement length (birth–death distance) of UDs are 8.19 minutes, 0.5 km?s^?1, 284 km, and 155 km, respectively. We also find a positive correlation between intensity–diameter, intensity–lifetime, and diameter–lifetime of UDs. However, UD properties do not show any significant relation with the decay rate or filling factor.  相似文献   

Thermonuclear X-ray burst of MXB 1658-298 with <Emphasis Type="Italic">NuSTAR</Emphasis>     

Rahul Sharma  Abdul Jaleel  Chetana Jain  Biswajit Paul  Anjan Dutta 《Journal of Astrophysics and Astronomy》2018,39(1):16

MXB 1658-298 is a transient Low-Mass X-ray Binary (LMXB), which shows eclipses, dips and bursts in its light curve. This source has undergone three active periods separated by long quiescent phases. The latest phase of enhanced X-ray emission was observed during 2015–2016. We have analysed broadband data from Swift/XRT and NuSTAR observations carried out in 2015. During NuSTAR observation, one thermonuclear X-ray burst took place. The X-ray emission during the burst was brighter by a factor of \(\sim 200\), compared to the pre-burst emission. This work focuses on the spectral analysis of MXB 1658-298 during the persistent and the burst phases using NuSTAR observation of 2015. We have also determined the temperature and radius evolution during the burst using the time-resolved spectroscopy. The burst phase shows mild Photospheric Radius Expansion (PRE).  相似文献   

SPIN: An Inversion Code for the Photospheric Spectral Line     

Rahul Yadav  Shibu K. Mathew  Alok Ranjan Tiwary 《Solar physics》2017,292(8):105

Inversion codes are the most useful tools to infer the physical properties of the solar atmosphere from the interpretation of Stokes profiles. In this paper, we present the details of a new Stokes Profile INversion code (SPIN) developed specifically to invert the spectro-polarimetric data of the Multi-Application Solar Telescope (MAST) at Udaipur Solar Observatory. The SPIN code has adopted Milne–Eddington approximations to solve the polarized radiative transfer equation (RTE) and for the purpose of fitting a modified Levenberg–Marquardt algorithm has been employed. We describe the details and utilization of the SPIN code to invert the spectro-polarimetric data. We also present the details of tests performed to validate the inversion code by comparing the results from the other widely used inversion codes (VFISV and SIR). The inverted results of the SPIN code after its application to Hinode/SP data have been compared with the inverted results from other inversion codes.  相似文献   

Dissolved major ions,Sr and 87Sr/86Sr of coastal lakes from Larsemann hills,East Antarctica: Solute sources and chemical weathering in a polar environment     

Mohammad Nuruzzama  Waliur Rahaman  Gyana R. Tripathy  Rahul Mohan  Shramik Patil 《水文研究》2020,34(11):2351-2364

Dissolved major ions, Sr concentrations and ⁸⁷Sr/⁸⁶Sr ratios of 10 coastal lakes from the Larsemann Hills, East Antarctica have been studied to constrain their solute sources, transport and glacial weathering patterns in their catchments. In absence of perennial river/streams, lakes serve as only reliable archive to study land surface processes in these low-temperature regions. The lake water chemistry is mostly Na-Cl type and it does not show any significant depth variations. Sr isotope compositions of these lakes vary from 0.7110 to 0.7211 with an average value of 0.7145, which is higher than modern seawater value. In addition to oceanic sources, major ions and Sr isotopic data show appreciable amount of solute supply from chemical weathering of silicate rocks in lake catchments and dissolution of Ca-Mg rich salts produced during the freezing of seawaters. The role of sulphide oxidation and carbonate weathering are found to be minimal on lake hydro-chemistry in this part of Antarctica. Inverse model calculations using this chemical dataset provide first-order estimates of dissolved cations and Sr; they are mostly derived from oceanic (seawater + snow) sources (cations approximately 76%) and (Sr approximately 92%) with minimal supplies from weathering of silicates (cations approximately 15%); (Sr approximately 2%) and Ca-rich minerals (cations approximately 9%); (Sr approximately 7%). The silicate weathering rate and its corresponding atmospheric CO₂ consumption rate estimates for Scandrett lake catchment (3.6 ± 0.3 tons/km²/year and 0.5 × 10⁵ moles/km²/year), are lower than that of reported values for the average global river basins (5.4 tons/km²/year and 0.9 × 10⁵ tons/km²/year) respectively. The present study provides a comprehensive report of chemical weathering intensity and its role in atmospheric CO₂ consumption in low-temperature pristine environment of Antarctica. These estimates underscore the importance of Antarctica weathering on atmospheric CO₂ budget, particularly during the past warmer periods when the large area was exposed and available for intense chemical weathering.  相似文献