Assessment of future climate variability and potential adaptation strategies on yield of peanut and Kharif rice in eastern India

Theoretical and Applied Climatology - Temperature and CO2 are the two most important climate parameters that affect crop yield directly. In this study, the impact of these two parameters on the...     

Design Charts for Selecting Minimum Setback Distance from Side Slope to Horizontal Trench System in Bioreactor Landfills

The primary objective of bioreactor landfill is to achieve adequate and rapid distribution of moisture in landfilled municipal solid waste (MSW) to accelerate the anaerobic biodegradation of the organic fraction within MSW. A horizontal trench system (HT) is commonly adopted for leachate distribution in MSW under pressurized conditions. However, this approach should be implemented carefully due to the potential instability of landfill slopes that comes from the generation and distribution of excessive pore fluid pressures. In this study, HT design charts are presented that determine the optimal location of horizontal trench systems from the side slope (i.e., minimum lateral setback distance) under continuous leachate addition with maximum applied injection pressures, for which the landfill slopes remain stable [factor of safety (FOS) where FOS ≥ 1.5]. Use of any higher injection pressure and/or shorter lateral setback distance of HT than the one presented in the design charts would result in an unacceptable design of the bioreactor side slope (FOS < 1.5). The design chart was developed based on a parametric study that used a numerical two-phase flow model that involved different slope configurations and landfill waste depths. MSW heterogeneity and anisotropy, as well as unsaturated hydraulic properties, were taken into consideration in these simulations. Transient changes in pore water and gas pressures due to leachate recirculation were accounted for dually in the slope stability computations. The importance of these design charts is illustrated using a practical example. Site-specific conditions and the expertise and prior experience of a designer or operator must also be adequately considered and utilized with the design charts presented here for the safe design of a horizontal trench system in a bioreactor landfill.     

Horizontal trench system effects on leachate recirculation in bioreactor landfills

Horizontal trenches (HTs) are constructed during the waste filling for leachate recirculation in bioreactor landfills. Leachate distribution depends on HT configuration (i.e., spacing between successive HTs), leachate injection rate, modes of injection, and hydraulic properties and MSW heterogeneity. Presently, the effects of these variables on the moisture distribution have not been studied systematically. This study provides a systematic evaluation of the effect of the HTs variables on the moisture distribution and pore fluid pressures. A two-phase flow model is used to model a bioreactor landfill having an HT leachate injection system. It quantifies the effects of the unsaturated hydraulic properties and MSW heterogeneity, trench configuration, leachate injection flux, and mode of injection on hydraulic behaviour. The results show that unsaturated hydraulic conductivity and MSW heterogeneity significantly shape the zone of influence and excess pore pressures. Under heterogeneous-anisotropic conditions, the leachate migrates more laterally and the developed pore-pressures are lower than for homogeneous MSW. A closely-spaced, multi-level, staggered HT system is found to provide uniform and adequate moisture distribution in MSW. An intermittent mode of injection that alternates between the shallow and deep trenches with a higher leachate injection flow rate is found to be effective to control the excess pore pressures.     

Fluoride contamination of groundwater in parts of eastern India and a preliminary experimental study of fluoride adsorption by natural haematite iron ore and synthetic magnetite

Incidence of high fluoride (F^?) in groundwater (>1.5 mg/L) in two tribal belts of eastern India, one around Chukru in the Palamau district of Jharkhand and the other around Karlakot in the Nuapada district of Odisha, has been studied. The maximum concentration of F^? in groundwater from dug wells and tube wells is 10.30 mg/L in Chukru and 4.62 mg/L in Karlakot. The groundwaters are mildly alkaline with pH ranges of 7.52–8.22 and 7.33–8.20 in Chukru and Karlakot, respectively. The F^? concentration is positively correlated with pH, electrical conductivity and SO₄ ^2? in both areas. The high F^? in groundwater resulted mainly from dissolution of biotite and fluorapatite in quartzofeldspathic gneiss. The ionic dominance pattern (in meq/L) is mostly in the order Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ among cations and HCO₃ ^? > SO₄ ^2? > < Cl^? > F^? among anions in the Karlakot groundwater. Preliminary adsorption experiments were conducted on natural haematite iron ore and synthetic magnetite to evaluate their potential for F^? removal from water. Effects of different parameters such as contact time, pH, adsorbent dose and initial F^? concentration on the adsorption capacity of these materials were investigated. Strong dependence of F^? removal on pH was observed for both the adsorbents. With natural haematite iron ore, the maximum F^? removal of 66 % occurred at an initial pH of 3.2 for a solution with F^? concentration of 3 mg/L, adsorbent dose of 7 g/L and overnight contact time. The haematite iron ore was observed to increase the pH of the F^? solution. Adsorption equilibrium was not achieved with this adsorbent even after a contact time of 45.2 h. In the case of synthetic magnetite, 84 % F^? removal was achieved after 2 min of contact time for a solution with F^? concentration of 6 mg/L, adsorbent dose of 10 g/L and initial pH of 7. The results indicate high potential of both natural haematite iron ore and synthetic magnetite as adsorbents of F^? in water.     

Characterisation and quality assessment of groundwater with a special emphasis on irrigation utility: Thirumanimuttar sub-basin, Tamil Nadu, India

Thirumanimuttar sub-basin is of particular importance in the study of groundwater quality due to the release of effluents from industries, agricultural, sewage and urban runoff, brining considerable change in water quality. An investigation was carried out by collecting a total of 194 groundwater samples for two seasons to decipher hydrogeochemistry and groundwater quality for determining its suitability for agricultural purposes. The water is neutral to alkaline in nature with pH ranging from 6.78 to 9.22 with an average of 7.37. Higher electrical conductivity (EC) was noted in NW and mid-downstream parts of the study area. Higher NO ₃ ^? was observed during post-monsoon (POM) due to the action of leaching and anthropogenic process. The piper plot reveals the dominance of Na⁺?CCl^? and Na⁺?CHCO ₃ ^? , mixed Ca²⁺?CNa⁺?CHCO ₃ ^? , mixed Ca²⁺?CMg²⁺?CHCO ₃ ^? and Ca²⁺?CSO ₄ ^? types of hydrogeochemical facies. Higher total hardness in the groundwater is due to the effect of dyeing and bleaching industries discharging effluents affects the quality of water. Residual Sodium Carbonate value indicates 56% of the samples are not suitable for irrigation purposes in both seasons. Higher sodium percentage is noted during PRM indicating the dominance of ion exchange and weathering. Higher sodium adsorption ratio was observed during POM indicating the effect of leaching and dissolution of salts into the aquifer matrix. USSL plot indicates 15% of samples record high salinity to medium sodicity. The Permeability Index indicates water is moderate to good for irrigation purposes. In general, groundwater in the study area is influenced by both natural and anthropogenic activities.     

Late Holocene (~ 2 ka) East Asian Monsoon variations inferred from river discharge and climate interrelationships in the Pearl River Estuary

A sediment core from the Pearl River Estuary (PRE) was analyzed for grain size and organic geochemistry parameters (TOC and δ¹³C_org). The results showed that high mean grain-size value and increased sand content were correlated with the high TOC and negative δ¹³C_org. These results indicated high river runoff in the PRE area. Peak river discharge occurred during the periods 1900–1750, 1500–1600, 1400–1200, 1000–900 and 750–600 cal yr BP. The main changes recorded in grain-size distributions, TOC contents, and δ¹³C_org variations appear to be directly related to monsoon precipitation in the sediment source area. An increased East Asian summer monsoon rainfall (EASM) and/or an enhanced East Asian winter monsoon rainfall could result in the increasing of monsoon rainfall. Typhoon related rainfalls could act as positive influence on precipitation levels. The study of the correlations between the rainfall records and ENSO activities revealed a close relationship between the monsoon rainfall in the PRE and the tropical Pacific variations. The frequent occurrence of ENSO might result in the southern migration of the EASM rain belt and lead to more typhoon-derived rainfall in the PRD during the late Holocene.     

Robe’s restricted problem of 2+2 bodies when the bigger primary is a Roche ellipsoid and the smaller primary is an oblate body

In this problem, one of the primaries of mass m ₁ is a Roche ellipsoid filled with a homogeneous incompressible fluid of density ρ ₁. The smaller primary of mass m ₂ is an oblate body outside the Ellipsoid. The third and the fourth bodies (of mass m ₃ and m ₄ respectively) are small solid spheres of density ρ ₃ and ρ ₄ respectively inside the Ellipsoid, with the assumption that the mass and the radius of the third and the fourth body are infinitesimal. We assume that m ₂ is describing a circle around m ₁. The masses m ₃ and m ₄ mutually attract each other, do not influence the motions of m ₁ and m ₂ but are influenced by them. We have extended the Robe’s restricted three-body problem to 2+2 body problem under the assumption that the fluid body assumes the shape of the Roche ellipsoid (Chandrashekhar in Ellipsoidal figures of equilibrium, Chap. 8, Dover, New York, 1987). We have taken into consideration all the three components of the pressure field in deriving the expression for the buoyancy force viz (i) due to the own gravitational field of the fluid (ii) that originating in the attraction of m ₂ (iii) that arising from the centrifugal force. In this paper, equilibrium solutions of m ₃ and m ₄ and their linear stability are analyzed. We have proved that there exist only six equilibrium solutions of the system, provided they lie within the Roche ellipsoid. In a system where the primaries are considered as Earth-Moon and m ₃,m ₄ as submarines, the equilibrium solutions of m ₃ and m ₄ respectively when the displacement is given in the direction of x ₁-axis or x ₂-axis are unstable.     

Resonance in a geo-centric satellite due to earth’s equatorial ellipticity

The resonances in a geocentric satellite due to earth’s equatorial ellipticity have been investigated. The resonance at five points resulting from the commensurability between the mean motion of the satellite and the earth’s equatorial ellipticity is analyzed. The amplitude and the time period of the oscillation have been determined by using the procedure of Brown and Shook. A comparison of their effects on the orbital elements has also been studied. It is observed that the amplitude and the time period of the oscillation decrease as Γ (angle measured from the minor axis of the earth’s equatorial ellipse to the projection of the satellite on the plane of the equator) increases in the first quadrant for all the resonance cases.     

How will Benthic Foraminifera Respond to Warming and Changes in Productivity?: A Laboratory Culture Study on Cymbaloporetta plana

Anthropogenic activities are likely to cause global warming. Global warming will affect marine productivityand thus food availability for marine organisms. Both the seawater temperature and food availability affect benthicforaminifera, the most abundant marine calcareous microorganisms. Therefore, a laboratory culture experiment wasconducted on Cymbaloporetta plana to understand the coupled effect of temperature(25°C, 27°C, 30°C) and food(102±5,203±9, 305±14, 407±18, 508±23 diatom cells). At all temperatures, growth increased with increase in food. The specimenssubjected to 27°C temperature attained the maximum growth and those subjected to 25°C were the smallest. All specimensfed with 508±23 cells reproduced, 0 irrespective of temperature. Of all the specimens without food, 40% at 27°C and 20% at25°C reproduced, whereas specimens subjected to 30°C did not reproduce. The 100% rate of reproduction at 27°C suggeststhat it is the optimum temperature for growth and reproduction. All the specimens at 30°C and without additional food,died, whereas at 25°C and 27°C, the mortality rate was 80% and 60%, respectively. The limited growth and reproductionwith decreasing food clearly indicates that food availability also controls the growth and reproduction of shallow waterbenthic foraminifer C. plana. Therefore, warming coupled with decreasing productivity is likely to severely affect thegrowth and abundance of shallow water benthic foraminifera.     

Morphotectonic analysis in Anandpur Sahib area,Punjab (India) using remote sensing and gis approach

Anandpur Sahib area of Rupnagar district (Punjab) was investigated using an integrated multi-disciplinary approach of geomorphological, structural, drainage and morphotectonic analysis through satellite data and GIS. Most commonly used geomorphic indices viz., channel sinuosity, drainage basin asymmetry, basin elongation ratio, mountain front sinuosity and valley floor to valley width ratio index have been used to identify the geomorphic indicators of active tectonics in the area. Existence of fluvial anomalies viz., abrupt changes in flow direction, flow against gradient, beheaded streams and river terraces reflect the strong structural control on the fluvial features. Asymmetric nature of drainage basin, elongated nature of the sub-watersheds, straight to curvilinear mountain fronts and narrow incised valley floors further substantiate the role of active tectonics in the region.