Studies of some diatomic molecules in the F- and early G-type dwarf stars     

Markandey Singh  Jai Prakash Chaturvedi 《Astrophysics and Space Science》1987,136(2):231-246

A critical analysis of CH, NH, OH, C₂, and CN molecules/radicals has been made in twenty-four F- and early G-type dwarfs at different effective temperature as well as in new constructed model atmosphere. Molecular indices of bandheads ofA-X system of CH, NH, OH, C₂, and CN have been obtained by using the data available in the literature (thirteen-colour and eight-colour photometry).Besides, some interesting plots of the molecular indices vs _eff, molecular abundances and molecular indices vs dissociation energy, reduced equivalent widths and FCF's vs dissociation energy for respective molecules have also been enumerated. It is found that the molecular indices at bandheads ofA-X system of CH, NH, OH, C₂, and CN are approximately constant (5810–6570 K). It is to be noted that the molecular indices decrease in the order OH, NH, CH, C₂, and CN at a given temperature.The dissociation equilibrium of CH, NH, OH, C₂, and CN is considered at 5810, 6570, and 7160 K phases in model atmosphere. At standard scale of abundance the molecular abundance and molecular index decrease in the order OH, NH, CH, C₂, and CN at any given phase, however, CN abundance and index increase (_eff=0.867-0.767). The amplitude of abundance and index variation decrease in the order NH, OH, CH, C₂, and CN (_eff=0.767-0.704).The reduced equivalent width decrease in the order OH, NH, CH, and C₂ and FCF's decrease in the order CH, OH, NH, CN, and C₂.The confrontation of models and observations of spectra of F- and early G-type dwarfs of parent molecules is of primary importance to investigate the physical conditions within atmospheres. Reliable excitation models are also requisite for interpreting spectroscopic observations of parent molecules and deriving molecular abundances.  相似文献   

Mapping Proterozoic unconformity-related uranium deposits in the Rockhole area, Northern Territory, Australia using landsat ETM+     

H.M. Rajesh   《Ore Geology Reviews》2008,33(3-4):382-396

The Rockhole area, Northern Territory, Australia, hosts a number of Proterozoic unconformity-related uranium deposits. The geology of the area features within Paleoproterozoic rocks of the Pine Creek Orogen, near the unconformity with overlying platform cover sandstone of the Paleo- to Mesoproterozoic McArthur Basin. Landsat Enhanced Thematic Mapper plus (ETM+) data was used in the Rockhole area to assist in mapping geological structures and lithology, and to identify anomalous concentrations of ferrous minerals, the product of alteration, which can be indicators of buried uranium mineralization. Several image-processing procedures were applied to the ETM+ data to identify, isolate and enhance mineralogical information as simple and complex false color composites. ETM+ 754 shown as red green and blue respectively was the best simple image. Overall, complex images based on Principal Component Analysis proved to be the most useful products. Sandstone, shale and siltstone, the target lithologies, Koolpin Formation, the target stratigraphic unit, and bleaching pattern due to the removal of iron(II) compounds, the target alteration pattern, were confidently mapped to provide information required by the mineral emplacement model, which ultimately identified areas of likely uranium mineralization. Thus the contrasting behavior of the two principle oxidation states of uranium and iron can be utilized to map/delineate bleached alteration zones associated with economic concentrations of uranium using multispectral sensors like Landsat or better hyperspectral sensors.  相似文献   

Evaluation of geochemical impact of tsunami on Pichavaram mangrove ecosystem,southeast coast of India   总被引：1，自引：0，他引：1  

Rajesh Kumar Ranjan  AL. Ramanathan  Gurmeet Singh 《Environmental Geology》2008,55(3):687-697

The 26 December 2004-tsunami has deposited sediments in the Pichavaram mangrove ecosystem, east coast of India. Ten surface and three core sediment samples were collected within 30 days of the event and analyzed for nutrients. Water samples were also analyzed to see the impact of tsunami on the geochemical behavior of nutrients. An increase in the concentration of various nutrients namely nitrate and phosphate was observed. The geochemistry of the mangrove forest was observed to be influenced by a number of factors like rapid increase of aquaculture farms, agricultural practices and the anthropogenic discharge from the nearby-inhabited areas. Further the sediment column was disturbed due to energetic tsunami waves, which has caused a sheer increase in the dissolved oxygen in water. As a result, the change in the redox potential has resulted in change in the nutrients absorbed/associated with the sediments. In addition, role of retreating water after tsunami on the nutrient geochemistry was also evaluated.  相似文献   

Some vibrational bands of theC-X system of V0 molecules in the umbral spectrum of the Sun     

Markandey Singh  Jai Prakash Chaturvedi 《Astrophysics and Space Science》1989,161(2):233-239

Vibrational transition probabilities namely Franck-Condon factors and r-centroids have been evaluated using an approximate analytical method for theC-X system of V0. Morse potential energy curves forX _{4 –} andC _{4 –} states of V0 have been constructed using the latest spectroscopic data. The value of r-centroids for the band have been found to increase linearly with the corresponding wavelength. We show results for new transition and ten new bands in the umbral spectrum of the Sun.  相似文献   

Whistler observations of the quiet time plasmasphere-ionosphere coupling fluxes at low latitude     

Lalmani  R. P. Singh  Rajesh Singh  Altaf Ahmad 《Earth, Moon, and Planets》1996,74(1):7-15

Observations of whistlers during quiet times made at low-latitude ground station Nainital (geomag. lat. 19 1 N) are used to deduce plasmasphere-ionosphere coupling fluxes. The whistler data from 3 magnetically quiet days are presented that show a smooth decrease in dispersion with time. This decrease in dispersion is interpreted in terms of a corresponding decrease in electron content of tubes of ionization. The electron densities, electron tube contents (10¹⁶ el/m²-tube) and coupling fluxes (10 el m^–1 s^–2) are computed by means of an accurate curve fitting method developed by Tarcsai (1975) and are in good agreement with the results reported by other workers.  相似文献   

YO molecule in the sun     

Markandey Singh  Jai Prakash Chaturvedi 《Astrophysics and Space Science》1990,165(1):119-129

Vibrational transition probabilities, namely Franck—Condon factors and -centroids have been evaluated by an approximate analytical method for the (A–X), (A–X), and (A–X) system of YO molecule. Morse potential energy curves forX ²⁺,A ²₂,A²₂, andA²₂, states of YO have been constructed using the latest spectroscopic data. The value of -centroids for the band have been found to decrease linearly with the corresponding wavelengths. We show results for two new transitions of (A–X) and (A–X) and five new bands of (A–X) of YO in the umbral spectrum of the Sun.  相似文献   

Morse pe-curves of AlH     

Markandey Singh  Jai Prakash Chaturvedi 《Astrophysics and Space Science》1990,173(1):27-30

Morse potential energy curves forC ¹⁺ andC ¹⁺ of AlH have been constructed. The energy values have been found to increase from vibrational levels 0 to 6 and decrease from vibrational levels 7 to 50 with the corresponding centre and half-width in the stateC ¹⁺. InC ¹⁺ state the energy values have been found to increase from vibrational levels 0 to 28 and decrease from vibrational levels 29 to 50 with the corresponding centre and half-width.  相似文献   

High rate anaerobic treatment of Sago wastewater using HUASB with PUF as carrier     

J. Rajesh Banu M.Sc  M.Phil.  Ph.D.  S. Kaliappan B.E.  M.E.  Ph.D.  D. Beck 《International Journal of Environmental Science and Technology》2006,3(1):69-77

Sago industry is one of the major small-scale sectors in India and over 800 units are located in the southern State of Tamilnadu. Processing of sago generates enormous quantities of high strength wastewater requiring systematic treatment prior to disposal. The present study is an attempt to treat the sago wastewater using Hybrid Upflow Anaerobic Sludge Blanket (HUASB) reactor, which offers the advantages of both fixed film and up flow anaerobic sludge blanket treatment. HUASB reactor with a volume of 5.6 L was operated at Organic Loading Rates varying from 10.7 to 24.7 kg COD/m³.day. After 130 days of startup, the reactor produced appreciable decrease in COD of wastewater and removed solids efficiently. The COD removal varied from 91–87%. While the removal of Total Solids was in the range of 61–57%, that of volatile solids varied from 70–67%. The ideal OLR for the reactor was 23.5 kg COD/m³.day. The findings of the study open up newer possibilities of design low cost and compact onsite treatment systems with very short retention periods.  相似文献   

Correct nomenclature for the Angadimogar pluton, Kerala, southwestern India     

H. M. Rajesh 《Journal of Earth System Science》2006,115(2):239-248

The proper usage of modal composition and geochemical classification of granitoids is discussed for assigning a proper nomenclature for the Angadimogar pluton, Kerala, southwestern India. This discussion is mainly aimed at addressing questions concerning the nomenclature of Angadimogar pluton (syenitevs. granite). Modal composition and whole-rock XRD data clearly show that the pluton exposed near Angadimogar is a quartz-syenite and its geochemistry is typical of a ferroan, metaluminous, alkali (A-type) granitoid  相似文献   

Charnockitic magmatism in southern India   总被引：2，自引：0，他引：2  

H. M. Rajesh  M. Santosh 《Journal of Earth System Science》2004,113(4):565-585

Large charnockite massifs cover a substantial portion of the southern Indian granulite terrain. The older (late Archaean to early Proterozoic) charnockites occur in the northern part and the younger (late Proterozoic) charnockites occur in the southern part of this high-grade terrain. Among these, the older Biligirirangan hill, Shevroy hill and Nilgiri hill massifs are intermediate charnockites, with Pallavaram massif consisting dominantly of felsic charnockites. The charnockite massifs from northern Kerala and Cardamom hill show spatial association of intermediate and felsic charnockites, with the youngest Nagercoil massif consisting of felsic charnockites. Their igneous parentage is evident from a combination of features including field relations, mineralogy, petrography, thermobarometry, as well as distinct chemical features. The southern Indian charnockite massifs show similarity with high-Ba-Sr granitoids, with the tonalitic intermediate charnockites showing similarity with high-Ba-Sr granitoids with low K₂O/Na₂O ratios, and the felsic charnockites showing similarity with high-Ba-Sr granitoids with high K₂O/Na₂O ratios. A two-stage model is suggested for the formation of these charnockites. During the first stage there was a period of basalt underplating, with the ponding of alkaline mafic magmas. Partial melting of this mafic lower crust formed the charnockitic magmas. Here emplacement of basalt with low water content would lead to dehydration melting of the lower crust forming intermediate charnockites. Conversely, emplacement of hydrous basalt would result in melting at higher {ie565-01} favoring production of more siliceous felsic charnockites. This model is correlated with two crustal thickening phases in southern India, one related to the accretion of the older crustal blocks on to the Archaean craton to the north and the other probably related to the collision between crustal fragments of East and West Gondwana in a supercontinent framework.  相似文献