Variation of lunar and solar geomagnetic tides with sunspot and geomagnetic activity     

K. S. Raja Rao  S. Jeevananda Reddy 《Pure and Applied Geophysics》1973,111(1):2291-2299

Summary Solar and lunar geomagnetic tides inH at Alibag have been determined by spectral analysis of discrete Fourier transforms following the method of Black and the well-known Chapman-Miller method. The seasonal variation inL ₂(H) is opposite to that inL ₂(D) with maximum in thed season and minimum in thej season. In bothH andD the enhancement due to sunspot activity is larger in lunar tide than in solar tide. Surprisingly, the enhancement due to magnetic activity is greater inL ₂(H) than inS ₁(H), while the contrary is true for declination. It is inferred that there is a local time component of the storm time variation contrary to the view expressed by Green and Malin. The enhancements in amplitudesL ₂ andS ₁ inH andD, due to sunspot activity and due to magnetic activity, have been separated. The results show that the amplitude at zero sunspot number increases with magnetic activity in all the four parameters, while the enhancement due to sunspot activity at different levels of magnetic activity decreases with increase ofK _p. But if bothK _p andR are increasing, whenK _p increases enhancement due toR decreases and whenR increases enhancement due toK _p decreases.  相似文献   

Problems concerning the magnetic behaviour and determination of curie points of certain basalts     

C. Radhakrishnamurty  P. K. S. Raja  S. D. Likhite  P. W. Sahasrabudhe 《Pure and Applied Geophysics》1972,93(1):129-140

Summary Magnetic hysteresis studies at different fields and temperatures have been carried out on several basalts. From such studies it would be often possible to delineate the single or multidomain character of the sample and in some cases to identify the magnetic minerals in them. However, in determining the Curie temperatures of the basalts, especially of those containing predominantly single domain grains, several difficulties arise, which are discussed.  相似文献   

On the reactive uptake of gaseous PAH molecules by micron-sized atmospheric water droplets   总被引：1，自引：0，他引：1  

S. Raja  K.T. Valsaraj   《Atmospheric Research》2006,81(4):277-292

A falling droplet reactor was used to study the heterogeneous oxidation of gaseous PAH molecules adsorbed on a 92 μm diameter water droplet by ozone. The dynamic partition constant for the PAH between the droplet and air and the first-order surface rate constant was measured. The increase in uptake with ozone concentration was due to increased mass transfer via surface reaction of co-adsorbed ozone and PAH. The surface rate constant was rationalized through the Langmuir–Hinshelwood mechanism. The rate constant was smaller for phenanthrene than naphthalene. The main reaction products identified in the aqueous phase indicated the peroxidic route for surface reaction of ozone with PAH. The heterogeneous reaction rate of ozone with adsorbed phenanthrene at the air–water interface of a 92-μm droplet was estimated to be 9300 times larger than the homogeneous reaction of ozone with phenanthrene in the gas phase and it was 76 times larger than the homogeneous oxidation by hydroxyl radical in the gas phase. For naphthalene that is more volatile, however, the homogeneous reaction with hydroxyl was more important. Increased organic carbon added to the droplet increased both the partition constant for phenanthrene and surface reaction with ozone. The partition constant for a droplet formed from actual fog water was much larger than for pure distilled water.  相似文献   

A Hybrid Spatio-Temporal Data Model and Structure (HST-DMS) for Efficient Storage and Retrieval of Land Use Information   总被引：1，自引：0，他引：1  

Raja Sengupta  Chen Yan 《Transactions in GIS》2004,8(3):351-366

While the incorporation of geographical and environmental modeling with GIS requires software support for storage and retrieval of spatial information that changes over time, it continues to be an unresolved issue with modern GIS software. Two complementary approaches have been used to manage the spatial and temporal heterogeneity within datasets that use a field‐based representation of the world. Some researchers have proposed new data models that partition space into discrete elements on an as‐needed basis following each temporal event, while others have focused on eliminating duplication of repeated data elements present in spatio‐temporal information. It is proposed in this paper that both approaches have merit and can be combined to create a Hybrid Spatio‐Temporal Data Model and Structure (HST‐DMS) that efficiently supports spatio‐temporal data storage and querying. Specifically, Peuquet and Duan's (1995) Event‐based Spatio‐Temporal Data Model (ESTDM) and the Overlapping R‐tree (Guttman 1984, Tzourmanis et al. 2000) are utilized to create a prototype used to store information about urban expansion for the town of Carbondale, Illinois.  相似文献   

Spatial Scale and Population Assignment Choices in Environmental Justice Analyses1     

Michael T. Most  Raja Sengupta  Michael A. Burgener 《The Professional geographer》2004,56(4):574-586

Environmental justice laws protect certain populations against discriminatory actions that may result from a myriad of enterprises, including transportation activities. Previous environmental equity studies examining the effects of transportation‐engendered externalities have been criticized on several points, including (1) that the choice of a reference population for comparison to the criterion variable may influence the outcome of research results and (2) that the selection and use of inappropriate methodologies intended to identify and characterize populations may foreordain research outcomes. This article examines the potentially confounding effects of selected spatial scale and population assignment strategies as applied to a study of excessive noise levels at a large Midwestern airport, finding that reported outcomes can vary significantly as a function of methodological choices.  相似文献   

Interaction of Vermiculite with Pb(II), Cd(II), Cu(II) and Ni(II) Ions in Single and Quaternary Mixtures          下载免费PDF全文

Kuppusamy Vijayaraghavan  Franklin D. Raja 《洁净——土壤、空气、水》2015,43(8):1174-1180

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Land Surface Processes Simulation Over Thar Desert in Northwest India     

P. Raja  C. V. Srinivas  K. B. R. R. Hari Prasad  Nilendu Singh 《Pure and Applied Geophysics》2016,173(6):2195-2214

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Late Pleistocene Paleoflood Deposits Identified by Grain Size Signatures,Parsons Valley Lake,Nilgiris, Tamil Nadu     

Priyanka Raja  Hema Achyuthan  K. Geethanjali  Pankaj Kumar  Sundeep Chopra 《Journal of the Geological Society of India》2018,91(5):547-553

A study involving grain size analysis was carried out from the Parsons valley lake deposit, Nilgiris, India to determine the depositional environments and paleoflood events since late Pleistocene period (～29,838 cal yr BP). A 72 cm lacustrine core was collected from the lake and eight organic rich sediment samples were AMS radiocarbon dated. The study reveals variations in the grain size distribution chiefly influenced by regional climatic conditions. Paleoflood events have been identified by the individual sedimentary flood signatures of varying changes in the magnitude of sediment supply from the background silty sediment matrix around ～29,838 and ～8405 cal yr BP.  相似文献   

Remote sensing and GIS based comparative morphometric study of two sub-watershed of different physiographic conditions,West Godavari District,A.P.     

G. Tamma Rao  V. V. S. Gurunadha Rao  Ratnakar Dakate  S. T. Mallikharjuna Rao  B. M. Raja Rao 《Journal of the Geological Society of India》2012,79(4):383-390

In this present study, Remote Sensing (RS) and Geographical Information System (GIS) techniques were used to update drainage and surface water bodies and to evaluate linear, relief and aerial morphometric parameters of the two sub-watersheds viz. Jilugumilli and Regulapadu in the northern part of West Godavari District, Andhra Pradesh. The area of Jilugumilli and Regulapadu watersheds spread over about 110 & 80 sq. km respectively. The morphometric analysis of the drainage networks of Regulapadu and Jilugumilli sub-watersheds exhibit sub-dendritic and sub parallel drainage pattern. The variation in stream length ratio changes due to change in slope and topography. It was inferred from the study that the streams are in a mature stage in Regulapadu and Jilugumilli watersheds, which indicated the geomorphic development. The variations in bifurcation ratio values among the sub-watersheds are described with respect to topography and geometric development. The stream frequencies for both sub-watersheds exhibit positive correlation with the drainage density, indicating increase in stream population with respect to increase in drainage density. The Jilugumilli watershed has a coarse drainage texture and Regulapadu sub-watershed is a fine drainage texture in nature. In the present study an attempt has been made to analyse the morphometric analysis of two sub-watersheds under different physiographic conditions. Morphometric analysis is one of the essential analyses required for development and management of watershed.  相似文献   

Geochemical processes and multivariate statistical analysis for the assessment of groundwater quality in the Swarnamukhi River basin,Andhra Pradesh,India     

Priyanka Patel  N. Janardhana Raju  B. C. Sundara Raja Reddy  U. Suresh  Wolfgang Gossel  Peter Wycisk 《Environmental Earth Sciences》2016,75(7):611

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