Stochastic simulation of droughts. Part 1: point droughts     

S. Mohan  P. K. Sahoo 《水文研究》2008,22(6):854-862

The number of drought events derived from the historic streamflow or rainfall series will be limited and produce results that are not very reliable. This study proposes a drought simulation methodology that uses a long sequence of synthetically generated monthly streamflow/rainfall series, from which it is possible to drive a large sample of drought events and the prediction of drought characteristics will be reliable. The modified Herbst method has been used to identify droughts in the generated streamflow and rainfall series. The drought simulation procedure is illustrated with a case study of the Bhadra reservoir catchment in Karnataka State, India. Monthly droughts were derived from both historic and generated monthly streamflow and rainfall series. The important drought characteristics were determined and the suitable probability distribution for each parameter was arrived at after studying seven different probability models. The use of the probability curves thus derived has been illustrated with examples (referred to in Part 1 as ‘point droughts’). Similarly, the development and application of stochastic models for the prediction of regional drought parameters have been illustrated with examples in the accompanying paper (Part 2: regional droughts). Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

The Well Logging Handbook,O. Serra. Editions Technip. 608 pp., €45/US$ 60, ISBN: 978-2-7108-0912-8.     

G. Mohan 《Journal of African Earth Sciences》2009,53(3):137

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Removal of Copper,Nickel, and Zinc Ions from Electroplating Rinse Water     

Meyyappan Revathi  Mohan Saravanan  Ahmed Basha Chiya  Manickam Velan 《洁净——土壤、空气、水》2012,40(1):66-79

Removal of copper, nickel, and zinc ions from synthetic electroplating rinse water was investigated using cationic exchange resin (Ceralite IR 120). Batch ion exchange studies were carried out to optimize the various experimental parameters (such as contact time, pH, and dosage). Influence of co‐existing cations, chelating agent EDTA on the removal of metal ion of interest was also studied. Sorption isotherm data obtained at different experimental conditions were fitted with Langmuir, Freundlich, Redlich–Peterson, and Toth models. A maximum adsorption capacity of 164 mg g^?1 for Cu(II), 109 mg g^?1 for Ni(II), and 105 mg g^?1 for Zn(II) was observed at optimum experimental conditions according to Langmuir model. The kinetic data for metal ions adsorption process follows pseudo second‐order. Presence of EDTA and co‐ions markedly alters the metal ion removal. Continuous column ion exchange experiments were also conducted. The breakeven point of the column was obtained after recovering effectively several liters of rinse water. The treated rinse water could be recycled in rinsing operations. The Thomas and Adams–Bohart models were applied to column studies and the constants were evaluated. Desorption of the adsorbed metal ions from the resin column was studied by conducting a model experiments with Cu(II) ions loaded ion exchange resin column using sulfuric acid as eluant. A novel lead oxide coated Ti substrate dimensionally stable (DSA) anode was prepared for recovery of copper ions as metal foil from regenerated liquor by electro winning at different current densities (50–300 A cm^?2).  相似文献   

Impact of Annular Solar Eclipse of 15 January 2010 on the Atmospheric Boundary Layer Characteristics Over Thumba: A Case Study     

D.?Bala SubrahamanyamEmail author  T.?J.?Anurose  Mannil?Mohan  M.?Santosh  N.?V.?P.?Kiran Kumar  S.?Sijikumar 《Pure and Applied Geophysics》2012,169(4):741-753

On 15 January 2010, Thumba (8.5°N, 76.9°E) witnessed one of the longest known noontime annular solar eclipses (ASEs) spanning a period of about 7 min, centered at 1314 hours local time. In this research article, we present a case study on the behaviour of the atmospheric boundary layer characteristics and its vertical structure in response to this rare celestial event by making use of a suite of different in-situ instruments. During the peak period of the ASE, the incoming solar irradiance was dimmed by about 87% of its normal values, resulting in a significant reduction in the magnitudes of turbulent kinetic energy and surface-layer turbulent fluxes of heat and momentum. The intensity and vertical thickness of the sea/land breeze circulation cell over the study domain also weakened. However, the mixed layer heights determined from balloon-borne GPS Radiosonde did not show any appreciable changes. Analysis of vertical profiles of thermodynamic parameters in association with the wind direction during ASE indicated the formation of a double mixed layer between 700 and 1500 m and is attributed to horizontal advection of a different airmass at those altitudes.  相似文献   

Influence of Co‐Factor on Enhancement of Bioplastic Production through Wastewater Treatment          下载免费PDF全文

Motakatla Venkateswar Reddy  Dhulipala Naga Sri Krishna Chitanya  Gauravarapu Navlur Nikhil  S. Venkata Mohan  Ponnapalli Nageswara Sarma 《洁净——土壤、空气、水》2014,42(6):809-814

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Arthrospira (Spirulina) Species as Bioadsorbents for Lead,Chromium, and Cadmium – a Comparative Study          下载免费PDF全文

Sundaramoorthy Balaji  Chandrasekaran Rajasekaran  Mohan Shalini  Ramamoorthy Siva  Rajan Kumar Singh  Mohammed Asif Akthar 《洁净——土壤、空气、水》2014,42(12):1790-1797

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Comparing seismic susceptibility models of the Himalayan terrain     

S. K. Som  P. Dasarwar  Murali Mohan  J. N. Hindayar  N. Thrideep Kumar  S. N. Chowdhuri  G. S. Darmwal  Harbans Singh 《Journal of Seismology》2016,20(3):827-863

The ongoing intra-continental collision between the Indian and Eurasian plates along the Himalayas has resulted in many damaging earthquakes with severe damages to man-made structures and natural landscapes due to ground shaking and ground failure, which in turn depends on geomorphological, geological and geophysical variables. Seismic susceptibility models are developed for Gangtok City by combining all the three variables using both knowledge-driven and data-driven methods on facet and grid cell terrain units. Finally, the results are critically evaluated by validation with the earthquake intensity data recorded during earthquake events. First-stage modelling attempt using different knowledge-driven methods on different terrain units shows bi-modal data distribution with low predictability due to extremely rugged topography with wide altitudinal variations within short distances. Second-stage modelling of separated population by using the same methodologies increases model predictability in which one model method describes the higher topographic levels better and the other model method is found to be better for lower topographic levels. Seismic susceptibility of the area is best described by composite models, combining different best methods of fine classification for lower and higher topographic levels having the same mapping/terrain units. Comparison of the composite models shows that the terrain unit does not play a significant role but the type of models selected determines the best possible seismic susceptibility map of the area.  相似文献   

Multiband optical monitoring of the blazars S5 0716+714 and BL Lacertae     

C. S. Stalin  Gopal-Krishna  Ram Sagar  Paul J. Wiita  V. Mohan  A. K. Pandey 《Monthly notices of the Royal Astronomical Society》2006,366(4):1337-1345

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Evaluation of metal contamination in coastal sediments of the Bay of Bengal, India: geochemical and statistical approaches   总被引：11，自引：0，他引：11  

Selvaraj K  Ram Mohan V  Szefer P 《Marine pollution bulletin》2004,49(3):174-185

Surface sediment samples collected from the inner shelf region of the Bay of Bengal, were analysed for the major elements and total and acetic acid available trace elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Si, Zn) to evaluate geochemical processes influencing their distribution. Major elemental analysis showed that the sediments had high concentrations of Si and relatively low concentrations of Al and Fe. Both major elemental and trace metal concentrations indicated that the sediments represent weathered products of granite and charnockite. Normalization of metals to Al indicated relatively high enrichment factors for Pb, Cd, Zn and Cr. The higher proportions of nondetrital Pb (66%), Cd (41%) and Co (28%) reveal metal contamination due to anthropogenic inputs. Factor analysis (FA) identified six possible types of sedimentological and geochemical associations. The dominant factor accounting for 26.9% of the total variance identifies an anthropogenic input and accumulation of nondetrital Cd, Co, Cr, Ni and Pb. Association of these metals with CaCO3 reveals that shell fragments in the surface sediments are likely act as a carrier phase for nondetrital metals. The results are discussed in the context of the sources and pathways of elements in the Bay of Bengal.  相似文献   

Equilibrium structures of rotationally and tidally distorted stellar models     

C. Mohan  R. M. Saxena  S. R. Agarwal 《Astrophysics and Space Science》1990,163(1):23-39

In this paper we present a method for computint the equilibrium structures of rotationally distorted stars as well as rotationally and tidally distorted primary components of the stars in binary systems. The method is based on the averaging technique of Kippenhahn and Thomas (1970) and utilizes the concepts of Roche equipotentials (Kopal, 1972). The method takes into account terms up to second-order of smallness in the rotational and tidal distortion parameters. The use of the method in obtaining the equilibrium structures of certain rotationally and (or) tidally distorted models of Main-Sequence stars is also illustrated.  相似文献