Geochemical studies on Kashmir loess profiles

Major and trace element concentrations of a few representative loess profiles in Kashmir valley are studied using EDXRF spectroscopy. Principal component analysis for pattern recognition has been employed to study association between elemental concentration variations in various horizons. The present study reveals that elements related to clay illuviation (K, Rb, Fe, Ti, Mn) and plant activity (Cu, Zn) are generally higher in B horizon of the palaeosols whereas Ca and Sr have a high concentration in the loess layers. Such an elemental concentration variation provides us with an objective index for identification and confirmation of palaeosols. There is further a close association in the movement of (i) K, Rb, (ii) Fe, Ti, Mn, (iii) Cu, Zn and (iv) Ca, Sr. These clusters of elements are also present in modern soils, suggesting that the soil characteristics in palaeosols have been preserved. Concentration of iron and titanium is also observed to be higher in loess profiles on Pir Panjal mountain flank which is dominated by basic rocks, compared to profiles on Himalayan flank, suggesting that the loess in Kashmir might have been derived from the nearby rocks in a localized way.     

Determination of thermodynamic properties of (Fe,Mg)-pyroxenes at 1000 K by the emf method

Emf measurements were made on the cell Pt|Fe,(Fe,Mg)_xSi₂O₆,SiO₂|(ZrO₂)_0.85(CaO)_0.15|Fe,FeO|Pt at 1000 K. Using the present data, the standard free energy of formation of ferrosilite (compound FeSiO₃), from the component oxides FeO and SiO₂, is calculated to be −6.35 ± 0.80 kJ/mol. The activity-composition relation for pyroxene solid solution shows that it has a positive deviation from ideality at 1000 K. The present results are compared with the results of other workers.ΔG_mix andΔG^ex are calculated and plotted againstN_FeSiO3.     

A Study on Soil Erosion in Pasighat Town (Arunachal Pradesh) India

Pasighat which lies on the foothills of the Himalayas is one of the important townsof Arunachal Pradesh. A very turbulent river named Siang flows through the townand causes frequent flash floods, inundating the low-lying areas. This river and townis also under threat due to continuous soil erosion. This soil erosion affects theneighbouring state of Assam as well. Due to the soil erosion this river known asBrahmaputra in Assam is constantly changing its course making a large numberof water channels with sand bars thus inundating vast cultivable land every year.The study analyses the cause of the problem at Pasighat in the backdrop of theexisting river system, morphology and the geographical evolution of the TransHimalayas.     

Heat and mass transfer of an oscillatory flow with Hall current

In the first part of these notes new expressions—simpler than any previously obtained—are presented in integral form for the derivatives of the α _n ⁰ -functions (required for an interpretation of the observed light changes of eclipsing variables) with respect to the fractional radiir _{1, 2} and projected separation δ of their centres in terms of the modified Bessel functionsK _{0, 1} (x) of the second kind; and utilized for establishing new asymptotic formulae for the computation of ‘boundary integrals’ of the formJ _?1 ⁰ ,n(μ). In the second part of this paper, by a resort to bi-polar coordinates, we shall establish a new type of expansions for the α _n ⁰ -functions valid for any type of eclipses, and converging faster than the expansions of the cross-correlation integral of the form (1) for α _n ⁰ that have so far been established.     

Experimental evidence of ion plasma oscillations in the apogee region of the Nike-Apache rocket

Several Nike-Apache rockets with Lang muir probe payloads were launched from Thumba (India) to study the disturbances produced by a moving rocket. The rockets were launched during different times of the day and night. It was found that low frequency ion plasma oscillations of the order of 1 KHz frequency were observed in the altitude region 145 to 200 km. This altitude region corresponds to the rocket apogee region where the rocket velocity is subsonic. The amplitude of the fluctuations was about 1 to 2% and was found to be dependant on rocket velocity electron density in the ambient medium, rocket spin and probe voltage. It was noticed that in the case of Centaure and Petrel rockets such types of oscillations were not observed. The Nike-Apache rockets are made of aluminium while Centaure and Petrel rockets are made of stainless steel.     

Vertical diffuse attenuation coefficient (Kd) based optical classification of IRS-P3 MOS-B satellite ocean colour data

The optical classification of the different water types provides vital input for studies related to primary productivity, water clarity and determination of euphotic depth. Image data of the IRSP3 MOS-B, for Path 90 of 27th February, 1998 was used for deriving vertical diffuse attenuation coefficient (K_d) and an optical classification based onK _d values was performed. An atmospheric correction scheme was used for retrieving water leaving radiances in blue and green channels of 412, 443, 490 and 550 nm. The upwelling radiances from 443 nm and 550 nm spectral channels were used for computation of vertical diffuse attenuation coefficientK _d at 490 nm. The waters off the Gujarat coast were classified into different water types based on Jerlov classification scheme. The oceanic water type IA (K _d range 0.035-0.040m^-1), type IB (0.042-0.065 m^-1), type II (0.07-0.1m^-1) and type III (0.115-0.14m^-1) were identified. For the coastal waters along Gujarat coast and Gulf of Kachchh, K_d(490) values ranged between 0.15 m^-1 and 0.35 m^-1. The depth of 1% of surface light for water type IA, IB, II and III corresponds to 88, 68, 58 and 34 meters respectively. Classification of oceanic and coastal waters based onK _d is useful in understanding the light transmission characteristics for sub-marine navigation and under-water imaging.     

Environmetric and GIS techniques for hydrochemical characterization of the Dal lake,Kashmir Himalaya,India

This research explains the background processes responsible for the spatial distribution of hydrochemical properties of the picturesque eutrophic Himalayan Lake, Dal, located in Kashmir valley, India. Univariate and multivariate statistical analyses were used to understand the spatiotemporal variability of 18 hydrochemical parameters comprising of 12,960 observations collected from 30 sampling sites well distributed within the lake at a grid spacing of 1 km² from March 2014 to February 2016. Hierarchical cluster analysis (HCA) grouped all the sampled data into three clusters based on the hydrochemical similarities, Discriminant analysis also revealed the same clusters and patterns in the data, validating the results of HCA. Wilk’s λ quotient distribution revealed the contribution of ions, nutrients, secchi disk transparency, dissolved oxygen and pH in the formation of clusters. The results are in consonance with the Principal Component Analysis of the whole lake data and individual clusters, which showed that the variance is maximally explained by the ionic component (46.82%) followed by dissolved oxygen and pH (9.36%), nitrates and phosphates (7.33%) and Secchi disk transparency (5.98%). Spatial variability of the hydrochemistry of the lake is due to the variations in water depth, lake water dynamics, flushing rate of water, organic matter decomposition, and anthropogenic pressures within and around the Dal lake ecosystem. Overall, the water quality of the lake is unfit for drinking due to the presence of coliform bacteria in the lake waters.