Environmental geochemistry of the River Gomti: A tributary of the Ganges River

Water and sediment samples collected from the Gomti River, a tributary of the Ganges River system, during the postmonsoon season have been analyzed to estimate major elemental chemistry. Water chemistry of the River Gomti shows almost monotonous spatial distribution of various chemical species, especially because of uniform presence of alluvium Dun gravels throughout the basin. The river annually transports 0.34×10⁶ tonnes of total suspended material (TSM) and 3.0×10⁶ tonnes of total dissolved solids (TDS), 69 percent of which is accounted for by bicarbonate ions only. Samples collected downstream of the city of Lucknow show the influence of anthropogenic loadings for a considerable distance in the river water. Na⁺, Cl^–, and SO₄ ^2– concentrations build up downstream. The bed sediment chemistry is dominated by Si (36 percent), reflecting a high percentage of detrital quartz, which makes up about 74 percent of the mineralogy of the bed sediments in the River Gomti. The average Kjeldahl nitrogen concentration (234 g/g) indicates indirectly the amount of organic matter in the sediments. The Hg concentration in sediments has been found to be higher (average 904 ppb) than the background value. The suspended sediments are well sorted, very finely skewed, and extremely leptokurtic, indicating a low energy condition of flow in the Gomti River. The influence of chemical loads in the Gomti has been found to be small or nonexistent on the Ganges River, perhaps because the water discharge of the Gomti (1.57 percent) to the Ganges is quite low.     

Forest cover mapping of East district,Sikkim using IRS-1A LISS II satellite data

Remote sensing techniques have been applied to classify tour density classes within each of the forest type along with other major landuse/landcover classes in the East district, Sikkim using IRS-1A LISS II satellite data pertaining to the period of November, 1988. The shadow problem in rugged terrain and difficulty in acquiring cloud free data for different seasons pose problems to achieve considerable mapping accuracy. In the present study, the forests of the district were delineated through supervised classification techniques using maximum likelihood algorithm into five forest types as sal forests, subtropical broad-leaved forests, Himalayan wet temperate forests, Rhododendron forests and alpine forests. The alpine forests were further stratified into two categories as moist alpine scrub and dry alpine scrub. The statistical data obtained from the present study shows that 55.47 percent of the total geographical area of the East district was under forest cover. An overall accuracy of more than 85 percent in correctly delineating forest classes was achieved.     

Effect of perturbed potentials on the non-linear stability of libration pointL 4 in the restricted problem

The non-linear stability of the libration pointL ₄ in the restricted problem has been studied when there are perturbations in the potentials between the bodies. It is seen that the pointL ₄ is stable for all mass ratios in the range of linear stability except for three mass ratios depending upon the perturbing functions. The theory is applied to the following four cases:

On the interior of the neutron star (II)

With the assumption, the physical 3-spacet = constant in a superdense star is spheroidal and the matter-density on the boundary surface of the configurationa = 2 × 10¹⁴ g cm^–3( the average matter density in a neutron star) Vaidya and Tikekar (1982) proposed an exact relativistic model for a neutron star. They suggested that their model can describe the hydrostatic equilibrium conditions in such a superdense star with densities in the range of 10¹⁴-10¹⁶ g cm^–3. Based on this model Parui and Sarma (1991) estimated the maximum limit of the density variation parameter for a stable neutron star (both for charged and uncharged) which is equal to 0.68, i.e. _max = 0.68.In this paper we have shown variation of central density per unit equilibrium radius (0/a), variation of mass, upper limit of density variation parameter both for charged and uncharged neutron stars at densities 10¹⁵ and 10¹⁶ g cm^–3, respectively. We have obtained _max = 0.68, i.e. the same as before. The important is that the duration of stability among the neutron star's constituents around _max will be shorter and shorter at higher densities as we proceed near the centre of the neutron star. In case of a charged neutron star, once stability among the constituents has been established, then unstability appears gradually maintaining linear relation between change in central density per unit equilibrium radius and change in mass whereas in case of uncharged neutron star, linear relation does not maintain.     

On the quiet-time Pc 5 pulsation events (Spacequakes)

A quiet-time Pc 5 event (designated Spacequake) of March 18, 1974, first noted on the Fort Churchill magnetopram, was studied using global data. Its amplitude was found to be largest in the northern part of the auroral zone and its period seemed to increase with latitude. The clockwise polarization of the event noted at Baker Lake and higher latitudes changed to counterclockwise at Fort Churchill in X-Y, X-Z and Y-Z planes. The resonance of a field line (L ? 10) excited due to an instability of the Kelvin-Helmholtz type may have given rise to the observed event. It is conjectured that the cause of instability at this high altitude was internal convection of the magnetosphere. Similar quiet-time events from four Canadian observatories were selected from approximately 11 years of magnetograms and their statistical analysis revealed that (i) occurrences maximized near dawn and dusk (ii) the amplitude-latitude profile peaked at Great Whale River (L ? 6.67), (iii) periods increased with increasing geomagnetic latitudes, (iv) a large number of events occurred in January, February and March every year, and (v) frequency of occurrence increased with increasing sunspot numbers. Comparison of these results with those available in the literature from analyses of satellite data clearly indicate that quiet-time Pc 5 events (Spacequakes) originate in the outer magnetosphere.     

Photoelectric study of the δ Scuti star HR 1225

The periodogram analysis of theV observations of the Scuti star HR 1225 has been carried out. Two frequencies of 6.415 cd (P ₀=0 _. ^d 1558) and 8.418 cd (P ₁=0 _. ^d 1188) have been determined. The period ratio ofP ₁/P ₀=0.762 indicates radial pulsation. The absolute magnitude, effective temperature and mass of the star are derived to be 1 _. ^m 05, 7600 K and 1.9M , respectively.     

Bianchi II,VIII, and IX viscous fluid cosmology

In this paper we study the exact solutions for a viscous fluid distribution in Bianchi II, VIII, and IX models. The metric is simplified by assuming a relationship between the coefficients of the metric tensor. Solutions are obtained in two special cases: in one an additional assumption is made where the matter density and the expansion scalar have a definite relation and in the other a barotropic equation of state of the formp= is assumed. While the Bianchi II solutions are already found in the literature the other two classes of solutions are apparently new.     

Structure of the marine boundary layer over north western Indian Ocean during 1983 summer monsoon

The spatial variability of the structure of the lower troposphere over the northwestern Indian Ocean for the period 12th July to 2nd September, 1983 has been studied using upper air data collected during the first scientific cruise of ORV Sagar Kanya.An analysis of thermodynamic structure and kinematics of the marine boundary layer for different zonal and meridional sections revealed the following features: (a) Temperature and humidity inversions were generally absent over the study area except over a few locations in the western region; (b) Large-scale subsidence was found over the central equatorial Indian Ocean; (c) The convective activity over the western Indian Ocean was found to be moderately suppressed as compared to the eastern region; (d) The zonal and meridional components of winds along the equator and 10° N zonal section exhibited a mirror-image-like distribution.     

A note on theH-functions of transfer problems in multiplying media

Some useful results and remodelled representations ofH-functions corresponding to the dispersion function $$T\left( z \right) = 1 - 2z^2 \sum\limits_1^n {\int_0^{\lambda r} {Y_r } \left( x \right){\text{d}}x/\left( {z^2 - x^2 } \right)} $$ are derived, suitable to the case of a multiplying medium characterized by $$\gamma _0 = \sum\limits_1^n {\int_0^{\lambda r} {Y_r } \left( x \right){\text{d}}x > \tfrac{1}{2} \Rightarrow \xi = 1 - 2\gamma _0< 0} $$      

Impact of Changes in Redox Conditions on Leaching of Some Elements from MSW Fly Ash

Abstract. Oxidation and reduction processes can influence extent of leaching of elements from solid waste. Three samples of municipal solid waste combustion fly ash were subjected to oxidizing and reducing conditions in order to evaluate leaching of elements in the Milli-Q water and fly ash (liquid to solid ratio, 100) mixtures. Although the oxidizing and reducing conditions were applied for 6 hours only, elements like Cs, Li, Mg, Sb, Tl and V leached more under oxidizing condition than under reducing condition in the case of all three ash samples. Cadmium, Pb and Zn leached more from all samples under reducing condition than under oxidizing condition. Leaching of other elements like Al, Ba, Cr, Cu, Ni and Rb was inconsistent with oxidizing or reducing conditions and varied from sample to sample, suggesting that factors other than redox may be more important in controlling leaching of these elements. Strong acid neutralization capacity of the fly ash samples let the pH vary within a narrow range, and thus severely limited the extent of leaching during the course of the experiment. Lead and Zn were the most sensitive while K and Na were the least sensitive to changes in redox conditions.