Watershed prioritization for soil erosion mapping in the Lesser Himalayan Indian basin using PCA and WSA methods in conjunction with morphometric parameters and GIS-based approach

Environment, Development and Sustainability - Watersheds in the subtropical Himalayan basins are highly prone to land degradation due to deforestation, landslides, intensive agriculture, population...     

Semi-parametric Bayesian density estimation using ranked set sample in the presence of ranking error

In this paper, we propose a Bayesian method to estimate the underlying density function of a study variable Y using a ranked set sample in which an auxiliary variable X is used to rank the sampling units. The amount of association between X and Y is not known, resulting in an unknown degree of ranking error. We assume that (X, Y) follows a Morgenstern family of distributions. The study variable Y is assumed to have a parametric distribution, with the distribution of the parameters having a Dirichlet process prior. A Markov chain Monte Carlo procedure is developed to obtain a Bayesian estimator of the desired density function as well as of the ranking error. A simulation study is used to evaluate the performance of the proposed method. An example from forestry is used to illustrate a real-life application of the proposed methodology.     

Alcohol ethoxysulfates (AES) in environmental matrices

Environmental Science and Pollution Research - Extensive use of surfactants in numerous fields resulted in their discharge into various environmental compartments including soil, sediment, and...     

Selection of suitable lichen bioindicator species for monitoring climatic variability in the Himalaya

Interspecific comparison in metals and PAHs profile in three lichen species, Flavoparmelia caperata, Phaeophyscia hispidula and Pyxine sorediata, were studied in different altitudinal gradients of the Western Himalayas. The species collected from 14 sites, enroute from Dehradun to Morinda (243 Km) including the trekking route 42 Km from Taluka to Morinda having an altitudinal gradient between 850–3,750 m, were analysed for their metals and PAHs. The species showed similar metal as well as PAHs profile under similar altitudinal gradients in the sequence of F. caperata > P. hispidula > P. sorediata. The difference in pollutant concentrations within each lichen species may be related to intrinsic attributes of the species, such as thallus morphology and the presence of lichen substances which are responsible for the sensitivity and accumulation potential of a particular species. Novelty of the present study lies on the fact that all the species show a similar efficiency of reflecting the environmental condition of the area, albeit the coefficient values of individual species for individual pollutant obtained by three-factor ANOVA revealed that the bioaccumulation affinity of F. caperata is significantly higher than P. hispidula and P. sorediata. For individual metals, F. caperata has a higher affinity for Al, Cr, Fe, Pb and Zn while P. hispidula has a significant positive affinity for Fe and Pb. PCA analysis of sites with respect to pollutant revealed the segregation of sites based on source and distance. Combining the bioaccumulation potential parameters along with geostatistical (GIS) techniques establishes that F. caperata species is a better accumulator of metals and PAHs in comparison to P. hispidula and P. sorediata in the temperate regions of the Himalaya.     

Effective oil removal from water by magnetically driven superhydrophobic and oleophilic magnetic titania nanotubes

Development of efficient techniques to combat the harmful effects of oil spill is an emerging field, where fabrication of new sorbents for selective removal of oil has become a hot topic for environmental scientists. The present study reports the preparation of superhydrophobic/oleophilic magnetic titania nanotubes via a facile hydrothermal method, followed by the treatment with octadecylamine, as potential magnetically driven sorbent for selective removal of oil from water surface. The magnetic nature (superparamagnetism at 300 K) of the nanotubes enabled magnetic removal of the oil-sorbed material from water surface. Wettability test of the material depicted a static water contact angle of 166 ± 1°, indicating its superhydrophobic character. Oil uptake experiments and contact angle measurements revealed its superoleophilicity with maximum oil sorption capacity >1.5 g/g for a variety of oils. In addition to the ease of magnetic removal, the nanotubes possess sufficient buoyancy, high selectivity, and quick rate of oil uptake and is more than five times reusable.     

Solar-driven technology for freshwater production from atmospheric air by using the composite desiccant material “CaCl<Subscript>2</Subscript>/floral foam”

In this communication, experiments have been performed to check the capability of the newly formed composite desiccant material (CaCl₂/floral) for the extraction of freshwater from atmospheric air. Three numbers of solar glass desiccant box type system (SGDBS) with a captured area of 0.36 m² each, have been used. The design parameters for the water production are height of glass from desiccant bed at 0.22 m, inclination in angle as 30°, the effective thickness of glass as 3 mm and number of glazing as single. The maximum yield by the new composite desiccant material is 0.35 ml/cm³/day. The efficiency of the system SGDBS with 37 % concentration of CaCl₂ is 76.44 %.     

Comparative study of solar-powered water production from atmospheric air using different desiccant materials

In this paper, experiments have been performed in order to determine the quantity of water produced from the atmospheric air using different desiccant materials named Silica gel, Activated alumina and Molecular sieve 13 X. On the bases of experimental results, a correlation is derived among the different temperatures and water production using Central Composite Design (CCD) of Response Surface Methodology. A newly designed solar glass desiccant box type system (SGDBS), three in number, has been used. Design parameters for the production of water has been taken as depth of material from the glass is 0.22 m, inclination in angle as 30°, effective thickness of glass as 3 mm and number of glazing as single. It has been found experimentally that the maximum quantity of water produced by Silica gel, Activated alumina and Molecular sieve 13 X is 160, 20 and 35 ml/kg/day, respectively. Whereas theoretically, value of water produced by the Silica gel, Activated alumina and Molecular sieve 13 X is 600, 28 and 60 ml/kg/day, respectively.