Mobility of trace and potentially harmful elements in the environment from high sulfur Indian coal mines

Coal mine rejects and sulfide bearing coals are prone to acid mine drainage (AMD) formation due to aqueous weathering. These acidic effluents contain dissolved trace and potentially harmful elements (PHEs) that have considerable impact on the environment. The behavior of these elements in AMD is mainly controlled by pH. The focus of the present study is to investigate aqueous leaching of mine rejects for prediction of acid producing potential, rates of weathering, and release of PHEs in mine drainage. Mine reject (MR) and coal samples from the active mine sites of Meghalaya, India typically have high S contents (1.8–5.7% in MR and 1.7–4.7% in coals) with 75–90% of the S in organic form and enrichment of most of the PHEs in rejects. Aqueous kinetic leaching experiments on mine rejects showed high acid producing potential and release of trace and potentially harmful elements. The elements (Sb, As, Cd, Cr, Co, Cu, Pb, Mn, Ni, V and Zn) in mine sample leachates are compared with those in mine waters. The concentrations of Al, Si, P, K, Ti, Mn, Fe, Co, Ni, Cu, Zn and Pb are found to increase with leaching time and are negatively correlated with pH of the solution. The processes controlling the release of these elements are acid leaching, precipitation and adsorption. The critical loads of PHEs in water affected by AMD are calculated by comparing their concentrations with those of regulatory levels. The Enrichment Factors (EFs) and soil pollution indices (SPIs) for the elements have shown that PHEs from coal and mine reject samples are mobilized into the nearby environment and are enriched in the associated soil and sediment.     

Interrelationship of rainfall,temperature and reference evapotranspiration trends and their net response to the climate change in Central India

The monthly rainfall data from 1901 to 2011 and maximum and minimum temperature data from 1901 to 2005 are used along with the reference evapotranspiration (ET₀) to analyze the climate trend of 45 stations of Madhya Pradesh. ET₀ is calculated by the Hargreaves method from 1901 to 2005 and the computed data is then used for trend analysis. The temporal variation and the spatial distribution of trend are studied for seasonal and annual series with the Mann-Kendall (MK) test and Sen’s estimator of slope. The percentage of change is used to find the rate of change in 111 years (rainfall) and 105 years (temperatures and ET₀). Interrelationships among these variables are analyzed to see the dependency of one variable on the other. The results indicate a decreasing rainfall and increasing temperatures and ET₀ trend. A similar pattern is noticeable in all seasons except for monsoon season in temperature and ET₀ trend analysis. The highest increase of temperature is noticed during post-monsoon and winter. Rainfall shows a notable decrease in the monsoon season. The entire state of Madhya Pradesh is considered as a single unit, and the calculation of overall net change in the amount of the rainfall, temperatures (maximum and minimum) and ET₀ is done to estimate the total loss or gain in monthly, seasonal and annual series. The results show net loss or deficit in the amount of rainfall and the net gain or excess in the temperature and ET₀ amount.     

‘Lineaments’ the Potential Groundwater Zones in Hard Rock Area: A Case Study of Basaltic Terrain of WGKKC-2 Watershed from Kalmeswar Tehsil of Nagpur District,Central India

Hard rock aquifer system, as it lacks in primary porosity, is complex because of heterogeneity, and hence its performance solely depends on secondary factors such as weathering, fractures, joints and lineaments, etc. As a result, there is no uniformity in behavior of such aquifer system which varies with the intensity of factors causing secondary porosity. In view of this aquifer system of hard rock, particularly multilayered aquifer system such as basalt, the targeting of deeper aquifer system becomes uncertain. Under this situation, mapping of lineament assumes great importance particularly for targeting the deeper aquifer. In view of this, a small watershed WGKKC-2 falling in Nagpur District of Central India has been studied in detail to understand the significance of lineaments on governing deeper aquifer system. The study has been carried out by deploying remote sensing technique for delineation of hydro geomorphology and lineaments vis-à-vis performance of bore wells. The results are encouraging which mainly emphasize the role of lineament mapping in hard rock aquifer system for identification of groundwater potential zones.     

The impact of extra-tropical transitioning on storm surge and waves in catastrophe risk modelling: application to the Japanese coastline

Catastrophe risk models are used to assess and manage the economic and societal impacts of natural perils such as tropical cyclones. Large ensembles of event simulations are required to generate useful model output. For example, to estimate the risk due to wind-driven storm surge and waves in tropical cyclone risk models, computationally efficient parametric representations of the wind forcing are required to enable the generation of large ensembles. This paper presents new results on the impact of including explicit representations of extra-tropical transitioning in parametric wind models used to force storm surge and wave simulations in a catastrophe risk modelling context. Extra-tropical transitioning is particularly important in modelling risk on the Japanese coastline, as roughly 40 % of typhoons hitting the Japanese mainland are transitioning before landfall. Using both a historical and idealized track set, we compare maximum storm surge and wave footprints along the Japanese coastline for models that include, and do not include, explicit representations of extra-tropical transitioning. We find that the inclusion of extra-tropical transitioning leads to lower storm surge (10–20 %) and waves (5–15 %) on the southern Japanese coast, with significantly higher storm surge and waves along the northern coast (25–50 %). The results of this paper demonstrate that useful risk assessment of coastal flood risk in Japan must consider the extra-tropical transitioning process.     

Population of excited rotational levels of HD and CO in interstellar clouds

Populations of the rotational levels of vibrational and electronic ground state of interstellar HD and CO have been calculated. Ultraviolet pumping and molecular formation have been found to be very important in the case of HD but not so in CO, the population distribution of which is mainly governed either by 3 K or by collisional excitation. The population inversion has been found to occur in HD but not in CO, the excitation temperatures of which pass through maximum for large ultraviolet flux. The population inversion at large density does not occur in HD, probably due to neglect of multipole collision. The observation of HD and CO in the excited states may be possible for suitable values of density and ultraviolet flux.On leave from Tata Institute of Fundamental Research, Bombay, India.     

Dark energy models with anisotropic fluid in Bianchi Type-VI 0 space-time with time dependent deceleration parameter

We present two dark energy (DE) models with an anisotropic fluid in Bianchi type-VI ₀ space-time by considering time dependent deceleration parameter (DP). The equation of state (EoS) for dark energy ω is found to be time dependent and its existing range for derived models is in good agreement with the recent observations. Under the suitable condition, the anisotropic models approach to isotropic scenario. We also find that during the evolution of the universe, the EoS parameter for DE changes from ω>−1 to ω=−1 in first model whereas from ω>−1 to ω<−1 in second model which is consistent with recent observations. The cosmological constant Λ is found to be a positive decreasing function of time and it approaches a small positive value at late time (i.e. the present epoch) which is corroborated by results from recent type Ia supernovae observations. The cosmic jerk parameter in our derived models is also found to be in good agreement with the recent data of astrophysical observations. The physical and geometric aspects of both the models are also discussed in detail.     

Evidence for the standard model through QSO absorption lines

I summarize the properties of the QSO absorption lines which provide evidence for the standard model of the Universe.     

Fluorescence efficiencies of electrons in second positive bands of N2 and first negative bands of N2+

Fluorescence efficiencies of electrons in a large number of bands of N₂ second positive and N_2⁺ first negative groups lying in the 3000–5200 Å region are calculated. At very low pressure where quenching is negligible the present values are within 15 per cent of the experimental data of Hartmann (1968). The efficiencies are found to be independent of the impact energies greater than 200 eV which is in accordance with other theoretical and experimental results. The ratio of the total efficiencies in N₂ second positive and N_2⁺ first negative groups is 1·31 and is about 20 per cent lower than the experimental values. The efficiencies at a higher pressure equal to 600 torr are compared with the experimental data of Davidson and O'Neil (1964a).     

Amino acids derived from Titan tholins

An organic heteropolymer (Titan tholin) was produced by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mbar pressure, roughly simulating the cloudtop atmosphere of Titan. Treatment of this tholin with 6N HCl yielded 16 amino acids by gas chromatography after derivatization of N-trifluroacetyl isopropyl esters on two different capillary columns. Identifications were confirmed by GC/MS. Glycine, aspartic acid, and alpha- and beta-alanine were produced in greatest abundance; the total yield of amino acids was approximately 10(-2), approximately equal to the yield of urea. The presence of "nonbiological" amino acids, the absence of serine, and the fact that the amino acids are racemic within experimental error together indicate that these molecules are not due to microbial or other contamination, but are derived from the tholin. In addition to the HCN, HC2CN, and (CN)2 found by Voyager, nitriles and aminonitriles should be sought in the Titanian atmosphere and, eventually, amino acids on the surface. These results suggest that episodes of liquid water in the past or future of Titan might lead to major further steps in prebiological organic chemistry on that body.