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  • 1
    ISSN: 1432-0495
    Keywords: Key words Damodar River ; Heavy metals ; Grain size ; Chemical fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The distribution of Si, Al, Fe, Mn, Cu, Zn, Ni and Cr in different grain-size fractions and geochemical association of Fe, Mn, Cu and Zn with 〈63-μm size fraction of bed sediments of Damodar River has been studied. In general, concentrations of heavy metals tend to increase as the size fractions get finer. However at two sites, near mining areas, the coarser particles show similar or even higher heavy metal concentrations than finer ones. The higher residence time and/or presence of coarser particles from mining wastes are possibly responsible for higher metal content in the coarser size fractions. The chemical fractionation study shows that lithogenic is the major chemical phase for heavy metals. Fe and Mn are the major elements of the lithogenic lattice, constituting 34–63% and 22–59%, respectively, of total concentrations. Fe-Mn oxide and organic bound fractions are significant phases in the non-lithogenic fraction. The carbonate fraction is less significant for heavy metal scavenging in the present environment and shows the following order of abundance Zn〉Cu〉Mn〉Fe. The exchangeable fraction of the Damodar sediments contains very low amounts of heavy metals suggesting poor bioavailability of metals.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 37 (1999), S. 124-136 
    ISSN: 1432-0495
    Keywords: Key words Damodar River ; Weathering ; Anthropogenic ; Heavy metal ; Total dissolved solids ; Total suspended matter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Water and bed sediment samples collected from the Damodar River and its tributaries were analysed to study elemental chemistry and suspended load characteristics of the river basin. Na and Ca are the dominant cations and HCO3 is the dominant anion. The water chemistry of the Damodar River basin strongly reflects the dominance of continental weathering aided by atmospheric and anthropogenic activities in the catchment area. High concentrations of SO4 and PO4 at some sites indicate the mining and anthropogenic impact on water quality. The high concentration of dissolved silica, relatively high (Na+K)/TZ+ ratio (0.2–0.4) and low equivalent ratio of (Ca+Mg)/(Na+K) indicate that dissolved ions contribute significantly to the weathering of aluminosilicate minerals of crystalline rocks. The seasonal data show a minimum ionic concentration in the monsoon season, reflecting the influence of atmospheric precipitation on total dissolved solids contents. The suspended sediments show a positive correlation with discharge and both discharge and suspended load reach their maximum value during the monsoon season. Kaolinite is the mineral that is possibly in equilibrium with the water. This implies that the chemistry of the Damodar River water favours kaolinite formation. The concentration of heavy metals in the finer size fraction (〈37 μ m) is significantly higher than the bulk composition. The geoaccumulation index values calculated for Fe, Mn, Zn, Ni and Cr are well below zero, suggesting that there is no pollution from these metals in Damodar River sediments.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Annales geophysicae 17 (1999), S. 1260-1267 
    ISSN: 0992-7689
    Keywords: Ionosphere (equatorial ionosphere; ionosphere-magnetosphere interactions; wave-particle interactions)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The morphology of ELF hiss events observed at low-latitude ground station Varanasi (L = 1.07, geomagnetic latitude 14°55′N) are reported, which consist of two types: (1) events which propagated in ducted mode along the geomagnetic field line corresponding to observing station Varanasi and (2) events which propagated in ducted mode along higher L-values (L = 4–6), after reaching the lower edge of ionosphere excite the Earth-ionosphere wave guide and propagate towards equator to be received at Varanasi. To understand the generation mechanism of ELF hiss, incoherent Cerenkov radiated power from the low latitude and middle latitude plasmasphere are evaluated. Considering this estimated power as an input for wave amplification through wave-particle interaction, the growth rate and amplification factor is evaluated which is too small to explain the observed wave intensity. It is suggested that some non-linear mechanism is responsible for the generation of ELF hiss.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Anaesthesia 50 (1995), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Changes in intra–ocular pressure during spontaneous ventilation with a laryngeal mask were compared with controlled ventilation using a tracheal tube in 40 patients undergoing intra–ocular surgery under general anaesthesia. Intra–ocular pressure was measured before induction, after establishing the airway, at the end of the operation and after removal of the airway device. Anaesthesia was induced with propofol and maintained with enflurane and nitrous oxide in oxygen. Mean end–tidal carbon dioxide tension was significantly higher during spontaneous ventilation than during controlled ventilation 5min after establishing the airway (5.7 versus 4.5) and at the end of surgery (6.1 versus 4.2) (p 〈 0.001). Despite this, intra–ocular pressures were lower than baseline and similar in the two groups throughout anaesthesia. At the end of surgery, intra–ocular pressure (mmHg) was 11.2 and 8.6 during spontaneous or controlled ventilation respectively. One min after removal of the device, mean intra–ocular pressure (mmHg) in the tracheal tube group (16.0) was slightly higher than baseline (15.3) and was significantly higher than the laryngeal mask group (10.9) (p 〈 0.01). Spontaneous ventilation with a laryngeal mask is an acceptable alternative to controlled ventilation with tracheal intubation in elective intra–ocular surgery.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 3679-3682 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high temperature-high pressure pyrophyllite cell with a graphite heater has limitations when temperature exceeds ∼2100 K. A conventional cell used with the cubic anvil high pressure apparatus has been modified to reach ∼3300 K. The heater power versus temperature calibration curve has been established using Pt–Pt10%Rh thermocouple up to 1900 K. For calibration above 1900 K, the heater powers required to initiate melting in Al2O3, Y2O3, and TiB2, and decomposition of α-SiC have been determined. The melting (or decomposition) of the specimens has been detected by examining the microstructure of the specimens recovered after pressure-temperature treatment. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 19 (1996), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Nostoc muscorum required an active proline oxidase in order to assimilate exogenous proline as a source of fixed nitrogen. A mutant strain (Acr) resistant to growth inhibition by L-azetidine-2-carboxylate (AC) was found to be deficient in proline oxidase activity, and to be a proline overaccumulator. Proline overaccumulation, resulting either from mutational acquisition of the Acr phenotype or from salinity-inducible uptake of exogenous proline, conferred enhanced salinity tolerance in this cyanobacterium.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of sol gel science and technology 8 (1997), S. 371-376 
    ISSN: 1573-4846
    Keywords: oxycarbide glass ; surface hydroxyls ; infra-red ; surface area
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In this study, the surface chemistry and structure of methyl-substituted silica gels and porous oxycarbide glasses were investigated. FTIR was used to measure the relative concentration of Si−CH3 and Si−OH as a function of the degree of methyl-substitution and the pyrolysis temperature. The gels and glasses were further heated, dehydrated or hydrated, in situ, within the FTIR spectrometer. In the temperature range of 800–850°C, high surface area oxycarbide glasses were created with no detectable surface hydroxyl groups. Oxycarbide glasses synthesized in argon at 700°C displayed a weak band for surface hydroxyl groups and reversible physisorption of water, while those synthesized at 850/900°C showed a complete absence of surface hydroxyl groups and the formation of vicinal silanols upon chemisorption of water. Isolated silanols were observed upon heat treatment in vacuum. Formation of aromatic carbon species was found to correlate with the decomposition of the methyl groups. The oxycarbide surface is quite stable to densification (presumably due to elemental carbon on the pore surfaces). In the absence of oxygen, porous silicon oxycarbide glass powders maintain surface areas 〉200 m2/g at 1200°C. However, oxidizing species in the atmosphere deplete the aromatic carbon species, and the glasses lose surface area.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Films of c-axis textured YBa2Cu3O7-x (YBCO) were grown on (1 0 0) oriented yttria stabilized zirconia substrates by high pressure glow discharge sputtering. The influence of substrate temperature on the texture and superconducting properties of the films is reported. X-ray pole figure analysis has shown that a c-axis orientation of the film normal to the substrate surface occurs at an optimized substrate temperature of 953 K. HREM investigation revealed that the deposited material nucleates and grows as YBCO with a large amount of stacking faults and with a few Y2BaCuO5 particles. A dominant cube-to-cube orientation relationship is found between the YBCO film and the substrate.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 32 (1997), S. 229-234 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Different types of silicides precipitate in high-temperature titanium alloys depending upon the composition and heat treatment of the alloys. However, there are inconsistencies and lacunae with respect to the chemical and crystallographic characteristics of the silicides and these are pointed out here. Hexagonal silicides s1 (a=0.7804 nm; c=0.5447 nm) and s2 (a=0.701 nm; c=0.368 nm) coexist in the ternary alloy Ti–5Zr–Si; however, only the s2 silicide exists when the addition of β stabilizing element is made. In addition, there is no common agreement about the space group of s2 silicide while the space group of s1 silicide was found to be P63/mcm (hP16). The (TiZr)6Si3 stoichiometry of s2 silicide is based on the experimental findings; however, the (TiZr)5Si3 stoichiometry of s1 silicide is simply deduced. Also the orientation relationships of silicides with α and β phases of the matrix are discussed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 32 (1997), S. 2595-2598 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Microstructural studies and X-ray diffraction combined with pole figure characterizations have been carried out on the melt-grown YBa2Cu3O7-x and GdBa2Cu3O7-x samples. The crystallographic orientation of the domains in melt-grown samples are highlighted based on the above studies.
    Type of Medium: Electronic Resource
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