Fabrication of Nanoparticle-Doped Polyvinyl Alcohol-Cellulose Acetate Membrane and Characterization of the Surface Enhancement

In the present study, nanocomposite polymeric membranes are fabricated using polyvinyl alcohol (PVA), cellulose acetate (CA) as polymers, and dimethyl sulfoxide (DMSO) as the solvent. To enhance the performance of the membrane, nanoparticles like TiO₂, CaO, CdO, and ZrO are added to the polymeric solution and the doped polymeric solution is cast on a glass plate. Nine combinations of membranes are fabricated with two different concentrations (0.1% and 0.2%) of nanoparticles. The basic properties of the membranes such as density, porosity, viscosity, permeability, pure water flux, and water content are studied for the samples. Membrane pore structure and surface properties are identified and it is found that doping nanoparticles on the surface of membranes improve mechanical strength, stability, pore size, etc., allowing the membranes to perform better in extreme industrial-level effluent treatment applications. High-resolution scanning electron microscopy (SEM) shows the homogeneous dispersion of ZrO, TiO₂, CaO, and CdO nanoparticles on the surface of the PVA-CA membrane. The doping of nanoparticles on the PVA-CA membrane results in improved mechanical strength and good chemical oxidation stability. In comparison, the PCD-TiO₂ sample shows high thermal stability and oxidation stability at high temperatures until 200°C, which has a high potential for treating industrial effluents.     

Storm Time Ionospheric-Tropospheric Dynamics: a Study Through Ionospheric and Lower Atmospheric Variability Features of High/Mid and Low Latitudes

Geomagnetism and Aeronomy - Geomagnetic storm is one of the major disturbances in Earth’s magnetosphere and its effect on ionosphere is a well studied area, yet there are a few aspects still...     

A study on zinc speciation of Tungabhadra River sediments,Kurnool, south India: A tool in metal pollution monitoring

The Tungabhadra River is one of the sacred rivers in south India. Industrial and mining operations on its banks generate enormous amounts of effluent that have led to substantial metal and nutrient contamination of the aquatic system. In the present investigation an attempt has been made to assess variation in the physico-chemical characteristics and speciation of zinc in the water and sediment of the Tungabhadra River. Most of the metal ions in the collected samples were in high concentrations compared to the applicable standards. The Individual Contamination Factor (ICF) of Zn was found to be more at Site-B compared to sites A and C. Zinc-bearing particles were characterized by the different morphologies measuring from large colloidal to small particles which were associated with biological structures or may be present in amorphous nature which were observed by Transition electron microscopy (TEM) with X-EDS (Energy dispersive spectrometry). In conclusion, the level of Zn contamination in the Tungabhadra River is increasing at an alarming rate due to industrial activities.     

Bulk viscous cosmological models of universe with variable deceleration parameter in Lyra’s Manifold

FRW models of universe in the presence of viscous fluid are investigated in the cosmological theory based on Lyra’s Manifold. By considering the deceleration parameter to be a variable and the viscosity coefficient of bulk viscous fluid to be a constant, exacts solutions have been obtained from which three forms of model of the universe are derived. The physical properties of the models are also investigated.     

Mapping and Assessment of Groundwater Potential in Bilrai Watershed (Shivpuri District, M.P.)—A Geomatics Approach

The main objective of the present work is to delineate the groundwater potential zones in Bilari watershed of district Shivpuri, Madhya Pradesh. Remote Sensing data and GIS were used to delineate the groundwater potential zones of the area. IRS-1D (LISS III) data have been utilized to extract information on various themes such as geomorphology, structure, drainage and land use/land cover. Available lithology and soil maps have also been used. DEM has been generated from contours taken from Survey of India topographical maps in order to obtain the slope percentage and slope aspect of the area. The groundwater potential zones were delineated by weighted overlay analysis. The themes geology, geomorphology, slope and soil were considered and the weightages assigned to different classes of respective themes according to their role in groundwater potential. Finally, five groundwater potential zones viz., very good, good, moderate; poor and very poor were delineated for the study area. It was estimated that about 110.41?sq km area which forms 37.55% of the total area are in the zones of very poor, poor and moderate category and about 183.75?sq km (62.45%) in zones of good and very good category.     

Distribution and risk assessment of polychlorinated biphenyls (PCBs) in the remote air and soil of Manipur,India

∑₂₅PCB congeners including dioxin-like compounds were analyzed at three sites of Manipur India to assess the level of polychlorinated biphenyls (PCBs) in air and soil. The ∑₂₅PCBs were higher in urban air (average 2,454 pg/m³), followed by the mountain air (average 2,109 pg/m³) and rural air (average 1,756 pg/m³). PCB levels observed in urban air were higher compared to PCB levels reported in major Indian metropolitan cities especially along the coastal region and were comparable with the pristine sites of India and also with some pockets of China and Europe. The heavier congeners (tetra, penta, tri and hexa) were dominant in both air and soil samples and show significant correlation with the ambient temperature. Emission of PCB congeners was investigated from soil surface. The total organic carbon present in soil shows the significant correlation (r ² = 0.8; p < 0.05) with the PCBs could indicate that the PCBs originated from the similar sources. Principal component analysis revealed that the sources of higher chlorinated PCB congeners are local emissions while long-range atmospheric transport process is responsible behind elevated levels of lower chlorinated PCBs. Total calculated toxic equivalent (TEQ) levels in soil (37.17–160.5 pg/g) were superior to reported TEQ level of agricultural soil in Delhi, India (0.01–105.40 pg/g). Back trajectory analysis showed that the observed high levels of PCB at Manipur may due to movement of air masses, mostly from the Northern and Southern India and to some extent from Myanmar.     

Spectroscopic Studies on Astrophysically Interesting TaO TaS, ZrS and SiO+ Molecules

The true experimental potential energy curves for the electronic ground states of astrophysically important TaO, TaS, ZrS and SiO⁺molecules are constructed by using the Rydberg–Klein–Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting techniques using the five parameters Hulburt-Hirschfelder (H-H) function. The estimated dissociation energies are 8.19 ± 0.17, 6.9 ±0.14, 5.89 ± 0.12 and 5.75 ± 0.12 eVfor TaO, TaS, ZrS and SiO⁺ respectively. These values are in good agreement with the literature values. The r-centriods and Franck–Condon factors (FC Factors) for the bands of K ² φ _5/2 - X ² Δ _3/2 (K-X) system of TaO, A-X ² Δ (A-X) and B-X ² Δ (B-X)systems of TaS, B ¹ Π - X¹ Σ⁺ (B-X) system of ZrS and B ²Σ⁺ - X² Σ⁺ (B-X) and A ² Π - X² Σ⁺ (A-X)systems of SiO⁺ molecules have been calculated. The Franck–Condon factors (FC factors) are evaluated by the approximate analytical methods of Jarmain and Fraser. The absence of the bands of these systems is explained. This revised version was published online in July 2006 with corrections to the Cover Date.     

Impacts of sea-level rise on coastal zones of Mauritius: insights following calculation of a coastal vulnerability index

Natural Hazards - Whilst climate change has been regarded as a growing concern in recent years due the disruptive and detrimental effects experienced across the globe, one of its most compelling...     

A higher-dimensional string cosmological model in Brans–Dicke theory of gravitation

Field equations in the presence of cosmic string source are obtained in a scalar tensor theory of gravitation proposed by Brans and Dicke (Phys. Rev. 124, 925 (1961)) with the aid of a five-dimensional Kaluza–Klein metric. An exact string cosmological model is presented which represents a five-dimensional Reddy string (Astrophys. Space Sci. 286, 2003b) in Brans–Dicke theory. Some physical properties of the model are also discussed