GIS-based Assessment and Management of Nitrogen and Phosphorus in R?nne? River Catchment, Sweden

Eutrophication in lakes, estuaries and rivers occur due to over-enrichment with nutrients. Amongst the various nutrients Nitrogen (N) and Phosphorous (P) are the elements which are considered as the major pollutants. The present study looks into the problem of managing nutrient losses both from point sources and diffuse sources. The study was carried out in the River R?nne? catchment in South of Sweden where N and P have been assessed by creation of a pollution inventory based on GIS technology. The nutrient loads from different land use types were estimated using export coefficients and evaluated using monitoring data. A comparative analysis is done on the measured and estimated N and P leaching from diffused sources and point sources. Protective zones were suggested to decrease the P export from agricultural land, and the distribution of construction cost was analyzed among administrative regions according to the proportion of catchments, cultivated land, nutrient leaching, protective zone and length of river section within each municipality. The estimated error of the nutrient amount from landuse using GIS is 9.75% and 12.71% for N and P, respectively. The diffused sources contribute 91.53% and 94.74% of the total N and total P respectively, so the creation of a protective zone could be an effective way to decrease the nutrient export. The study demonstrates the power of GIS as a tool to analyze problems related to environmental monitoring and planning at administrative level, which could help in decision making and support for better management of the water resources.     

Radioactive occurrence in sediments of Cenozoic age near Bandha village,Jaisalmer district,Rajasthan

The radioactivity is dependent on the isotope and their concentration in the mineral such as potassium (K), uranium (U) and thorium (Th). In this paper the presence of a 3 to 5 m thick uranium and thorium bearing sediment of Cenozoic age is reported above Goru Formation of Jaisalmer basin. Gamma ray log response of Well-1 which falls under the study area has marked with very high GR (gamma ray) readings ranging from 350-1488 API coupled with high uranium and thorium content from spectral gamma ray log ranging from 92-178 ppm and 60-80 ppm respectively at the depth of 50 m from ground surface (-110m above MSL). Further studies are required to delineate the lateral thickness variation for mining purpose which may be a radioactive source.     

Catalytic hydrothermal carbonization of invasive macrophyte Hornwort (<Emphasis Type="Italic">Ceratophyllum demersum</Emphasis>) for production of hydrochar: a potential biofuel

Biofuels are environment friendly and economical. First-generation biofuels are made from sugar, starch and vegetable oils, and have an impact on food security, while second generation biofuels are generated from plant or algal material and are greener and sustainable. The present work focused on lab-scale application of hydrothermal carbonization to convert aquatic weed Ceratophyllum demersum into a second-generation biofuel—hydrochar. Hydrothermal carbonization has been carried out with and without catalysts in a high-pressure reactor under subcritical temperatures 240–320 °C, residence times 10–40 min and biomass to water dilution ratios varying from 1:4 to 1:12. Under noncatalytic conditions higher heating value and energy density were highest, 24.11 MJ/kg and 1.64 respectively at temperature of 300 °C and residence time of 30 min. The calorific value of noncatalytic hydrochar was enhanced further, respectively, to 29.0, 27.5 and 26.48 MJ/kg by catalysts KOH, Na₂CO₃ and acetic acid. Catalytic hydrochar had H/C and O/C atomic ratios of same order as that of high-rank bituminous coal. Van Krevelen diagram indicated KOH to be better catalyst followed by Na₂CO₃ and acetic acid. Hydrochar yield of 38% obtained in noncatalytic hydrothermal carbonization decreased with catalysts in following order; acetic acid > Na₂CO₃ > KOH, however, energy density was enhanced in order KOH > Na₂CO₃ > acetic acid. The research can prove a way forward in the direction of meeting part of global energy demand. At the same time, the problem of secondary pollution caused by piling up and decay of aquatic weeds will also be addressed to.     

Delineation of potential fluoride contamination zones in Birbhum,West Bengal,India, using remote sensing and GIS techniques

Birbhum district in West Bengal, India, is one of the most severely affected districts by fluoride-contaminated groundwater. Fluoride content as high as 20.4 mg/L has been reported. Several cases of fluoride-related disorder such as dental fluorosis and skeletal fluorosis have been reported to be endemic in the district. Proper management of groundwater is very crucial. This contribution has been carried out for delineating potential fluoride-contaminated zones (PFCZ) in Birbhum district with the implementation of weighted overlay analysis in GIS environment. Twelve different potentially influential environmental parameters are integrated and evaluated. The final output map was categorised into two subclasses, i.e. ‘low’ and ‘high’, where the low region represents fluoride concentration of 1.5 mg/L and below and the high region represents fluoride concentration above 1.5 mg/L. The outcome reveals that approximately 24.35% of the study area falls under PFCZ, whereas about 75.65% of the study area falls under the safe zone with respect to potential fluoride contamination. On validation of the PFCZ, the reported fluoride contamination data in groundwater shows an overall 87.50% accuracy in prediction via superimposition method and 89.06 and 85.85% success and prediction rates, respectively, when validated with success and prediction rates.     

Nonsingular charged analogues of Schwarzschild’s interior solution

The problem of finding nonsingular charged analogue of Schwarzschild’s interior solutions has been reduced to that of finding a monotonically decreasing function f. The models are discussed in generality by imposing reality condition on f. It is shown that the physical solutions are possible only for surface density to central density ratio greater than or equal to 2/3 i.e. $\frac{\rho_{a}}{\rho_{0}}\ge2/3$ . The unphysical nature of solutions with linear equation state has been proved. A generalization procedure has been utilized to generalize solutions by Guilfoyle (1999). Recently found solutions by Gupta and Kumar (2005a, 2005b, 2005c) are generalized by taking particular form of f and seen to have higher mass and more stable. The maximum mass is found to be 1.59482 M _Θ . The models have been found to be stable once the physical requirements are established due to mass to radius less than 4/9, total charge to total mass ratio less than 1 and redshift quite low.     

Reconciling theory with observations: elements of a diagnostic approach to model evaluation

This paper discusses the need for a well‐considered approach to reconciling environmental theory with observations that has clear and compelling diagnostic power. This need is well recognized by the scientific community in the context of the ‘Predictions in Ungaged Basins’ initiative and the National Science Foundation sponsored ‘Environmental Observatories’ initiative, among others. It is suggested that many current strategies for confronting environmental process models with observational data are inadequate in the face of the highly complex and high order models becoming central to modern environmental science, and steps are proposed towards the development of a robust and powerful ‘Theory of Evaluation’. This paper presents the concept of a diagnostic evaluation approach rooted in information theory and employing the notion of signature indices that measure theoretically relevant system process behaviours. The signature‐based approach addresses the issue of degree of system complexity resolvable by a model. Further, it can be placed in the context of Bayesian inference to facilitate uncertainty analysis, and can be readily applied to the problem of process evaluation leading to improved predictions in ungaged basins. Copyright © 2008 John Wiley & Sons, Ltd.     

Some aspects of volcanic ash layers in the Central Indian Basin

 Intercalated volcanic ash layers in two deep-sea sediment cores from the Central Indian Basin (CIB) are examined for the possibility of an in situ source of suboceanic volcanism. An in situ source has been predicated based on the bottom morphological structures and activation of seamounts during the geological past. The tentative correlation between depositional ages of the ash layer horizons and the period of global climatic cooling events reinforces the hypothesis that the suboceanic volcanic episode might have been initiated during the onset of glaciation. Received: 20 June 1995 / Revision received: 11 May 1998     

Estimation of seismic drift demands for frame structures

A process is outlined and evaluated for the estimation of seismic roof and storey drift demands for frame structures from the spectral displacement demand at the first mode period of the structure. The spectral displacement demand is related to the roof drift demand for the multi‐degree‐of‐freedom (MDOF) structure using three modification factors, accounting for MDOF effects, inelasticity effects, and P‐delta effects. Median values and measures of dispersion for the factors are obtained from elastic and inelastic time history analyses of nine steel moment resisting frame structures subjected to sets of ground motions representative of different hazard levels. The roof drift demand is related to the storey drift demands, with the results being strongly dependent on the number of stories and the ground motion characteristics. The relationships proposed in this paper should prove useful in the conceptual design phase, in estimating deformation demands for performance assessment, and in improving basic understanding of seismic behaviour. Copyright © 2000 John Wiley & Sons, Ltd.     

GPS-derived precipitable water vapour and its comparison with MODIS data for Almora, Central Himalaya, India

The present study is an attempt to analyse the precipitable water vapour (PWV) derived from Global Positioning System (GPS) and observed meteorological data over Almora, Central Himalayan Region. The PWV values derived using GPS study is compared with the corresponding moderate resolution imaging spectro-radiometer (MODIS) data. The statistical analysis reveals a positive correlation between both methods. Moderate resolution imaging spectroradiometer near-infrared (MODIS NIR) clear column water vapour product shows a higher correlation (R ² = 90–93 %) with GPS-derived precipitable water vapour on annual scale as compared to the seasonal scale (R ² = 62–87 %). MODIS is found to be overestimating in NIR clear column where the magnitude of bias and RMSE show systematic changes from season to season. Monsoon is an important phenomenon in the Indian weather context and holds significant importance in Central Himalayan ecosystem. The monthly and seasonal variation in precipitable water vapour is related with monsoon onset in the region. Diurnal variations in precipitable water vapour are studied with other meteorological data over Almora during dry and wet season. The precipitable water vapour had minimum value in the morning, increases in the afternoon to evening and again decreases to the midnight in both the dry and wet seasons. These results suggest that diurnal variation of water vapour is caused by the transport of water vapour by thermally induced local circulation.