Study on activity of radium,radon and physicochemical parameters in ground water and their health hazards around Tumkur industrial area

Journal of Radioanalytical and Nuclear Chemistry - The activity of radium (226Ra), radon (222Rn) and physicochemical parameters in ground water around study area were estimated by standard...     

The effect of meteorological parameters on radon concentration in borehole air and water

Seasonal and short term variations of ²²²Rn activity concentration in borehole air and water of the borehole drilled in cracked quartzite were studied and possible response on meteorological parameters was examined. Seasonal change of radon concentration in borehole air due to atmospheric temperature was confirmed. Short term variation of radon concentration in borehole air coincided with the atmospheric pressure changes. The strong impact of rainfall on radon concentration values was observed both in air and water environments. The decrease of radon content in borehole air and water followed radioactive decay law exclusively in spring and summer month. Contrary to borehole water, rainfall increased radon concentration in borehole air during spring and summer months only. In this paper the results from two and half years of investigation are presented.     

Study of uranium contamination of ground water in Punjab state in India using X-ray fluorescence technique

The elemental concentration of uranium in the samples collected from the ground water and the canal water in the Bathinda district of Punjab state, India, have been investigated using X-ray fluorescence technique. The residues obtained after drying the water samples were analysed using the energy dispersive X-ray fluorescence spectrometer consisting of Mo-anode X-ray tube equipped with selective absorbers as an excitation source and an Si(Li) detector. The uranium concentration values in significant fraction of the shallow ground water samples from the hand pumps is found to be above the permissible level of 15?ppb recommended by World Health Organisation for the drinking water, and its values in the canal water samples are below 5?ppb. To investigate the flyash from the coal-fired thermal power plants as a possible source of ground water contamination, the water samples collected from the surroundings of the power plants and the flyash samples were also analyzed. The results rule out flyash as a source of uranium contamination. Agrochemical processes occurring in the calcareous soils in the region are the favoured potential source of uranium contamination of the ground water.     

Transport and physicochemical parameters of polypentenamer

Physicochemical properties of a cis-polypentenamer—a hydrocarbon polymer with a low glass transition temperature (T _g = 168.8 K)—have been studied. Measurements of permeability coefficients P in rubbery material for a wide range of gases (He, H₂, O₂, N₂, CO₂, CH₄, C₂H₆, C₃H₈, and n-C₄H₁₀) indicate a high permeability of this polymer for which the values of P are only slightly lower than those of the most permeable rubber—poly(dimethylsiloxane). The method of inverse gas chromatography has been employed to estimate solubility coefficients S for n alkanes C₃–C₁₀ and cycloalkanes in cis-polypentenamer in the range from 25 to 150°C. It has been shown that the solubility coefficients linearly increase in lnS-T _cr ² coordinates, where T _cr is the critical temperature of a solute. In terms of the above correlation, the solubility coefficients of light gases have been estimated and the diffusion coefficients D of gases in the same polymer have been calculated via the formula P=DS. The free volume in cis-polypentenamer has been studied by positron annihilation lifetime spectroscopy. The temperature dependence of the positronium lifetime τ ₃ that characterizes the size of the free volume element in a polymer demonstrates saturation at temperatures above 250 K. This effect is probably related to a rapid migration of fluctuation holes in the rubbery polymer at temperatures remote enough from its glass transition temperature.     

Protolytic dissociation of cyanoanilines in the ground and excited state in water and methanol solutions

The effect of cyano substituents on the photoacidity of mono- and dicyanoanilines has been investigated. It was demonstrated that the cyano substitution increases significantly the acidity of aniline derivatives in the excited state in comparison to the ground state. 3,5-Dicyanoaniline is the strongest acid in the lowest excited singlet state, while 4-cyanoaniline is the weakest one. The derivatives of aniline with two cyano groups in o,o'-position show different properties from those characteristic for aniline and other investigated cyanoanilines. In the methanol solution with sodium methanolate the anions of 2,6-dicyano-3,5-dimethylaniline and 2,6-dicyano-3,5-diphenylaniline appear already in the ground state. The electronic ground and excited state charge distributions and dipole moments of all investigated cyanoanilines have been evaluated by ab initio calculations using the GAMESS program.     

Determination of air-loop volume and radon partition coefficient for measuring radon in water sample

A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10–30 °C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0–75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H₂O and BigBottle RAD-H₂O. The results have shown good agreement between this method and the standard methods.     

Simplified theoretical approaches to calculate radon concentrations in walls and ground

Journal of Radioanalytical and Nuclear Chemistry - Simple mathematical ways of calculating the radon concentrations in walls and ground are presented. The methods exploit Fick’s second law in...     

A modified LEPS surface for the ground state of the water molecule

A modified LEPS potential surface using a Sato parameter which is a function of the internuclear coordinates has been developed for the ground state of the water molecule. By adjusting the Sato parameter many of the known properties of the water potential are fitted with this surface.     

Study of the influence of the lithological and hydrogeological parameters of aquifers on the radon emanation from underground waters using solid state nuclear track detectors

Radon-to-thoron ratios as well as radon and thoron activity concentrations in different underground water samples belonging to different aquifers in the Moroccan Middle Atlas area have been evaluated by LR-115 and CR-39 solid state nuclear track detectors (SSNTD) using a new calibration method. The radon isotope (²²²Rn) was used as a tracer for studying the water exchange between different aquifers of the area studied. The influence of the lithological and hydrogeological parameters of the aquifers on radon emanation were investigated.     

Arsenic speciation and other parameters of surface and ground water samples of Jamshoro,Pakistan

This study evaluated and interpreted complex data sets of water samples collected from different sampling origins of ground water (hand pump and tube well) and surface water (municipal, river and canal). The aim was to provide information concerning the apportionment of pollution sources to obtain better information about water quality and possible distribution of As with respect to its speciation. The As (III) formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, while total iAs in water samples was adsorbed on titanium dioxide (TiO₂) and determined by electrothermal atomic absorption spectrometry. The accuracy of the proposed methodologies was confirmed by standard addition method. The recoveries of As (III) and total inorganic arsenic (iAs) were found to be >98%. The results revealed that the ground water of the area under study was more contaminated as compared to surface water samples. The mean concentration of As (III) and As (V) in the surface water samples was found to be 15.8 and 6.00?µg?L^?1, respectively, whereas, in the case of ground water samples, the contents of As (III) and As (V) ranged from 6.20 to 51.0 and 6.40 to 53.0?µg?L^?1, respectively. Principal component analysis performed on a combined (tube well and hand pump) samples data set extracted two significant factors explaining more than 60% of total variance, which suggested that the contamination sources might be natural or anthropogenic.     

Mechanistic impact of water addition to SmI2: consequences in the ground and transition state

The mechanistic impact of water addition to SmI2 on the ground state and rate-limiting transition state structures in the reduction of benzyl bromide was determined using UV-vis spectroscopy, cyclic voltammetry, vapor pressure osmommetry, and stopped-flow spectrophotometric studies. The results obtained from these studies show that, upon addition of water, SmI2 in THF (or DME) becomes partially water-solvated by displacing metal-coordinated solvent. Further addition of water displaces remaining bound solvent and induces a monomer-dimer equilibrium of the SmI2-water complex. Concomitant with this process, a thermodynamically more powerful reductant is created. Rate studies on the reduction of benzyl bromide by SmI2-water are consistent with reaction occurring through a dimeric transition state with the assembly of the activated complex requiring an equivalent of water at low concentrations but not at higher concentrations. The mechanistic complexity of the SmI2-water system shows that simple empirical models describing the role of water in SmI2-mediated reductions are likely to contain a high degree of uncertainty.     

Study of the B"B 1Sigmau+ state of H2: transition probabilities from the ground state, dissociative widths, and Fano parameters

The transition probabilities, the dissociation widths, and the associated Fano parameters for rovibronic lines with J"=0,...,3 of the absorption bands of the B"B 1Sigmau+ state out of the X 1Sigmag+ v"=0 ground state were measured over the complete vibrational progression, showing clearly that only the inner-well state with B" 4psigma character can absorb vuv light and predissociate efficiently. The absolute values of these transition probablities, predissociation widths, and Fano parameters were found to agree well with ab initio calculations if one takes into account that the calculations neglect nonadiabatic couplings.     

Phase state and physicochemical properties of systems containing ammonium tungstate or ammonium vanadate, polyvinylpyrrolidone, and water

Isothermal sections of ammonium dodecatungstate-polyvinylpyrrolidone-water and ammonium vanadate-polyvinylpyrrolidone-water phase diagrams have been designed. The combination of visual or microscopic examination and refractive index and density measurements was employed in analysis. The fields of homogeneous polymer-salt solutions and a two-phase field in which a salt phase exists were found in the systems have been found in the systems. Exposure of the vanadate system to light increases the solubility of the salt. In the heterogeneous field of this system, colored precipitates appear because of the solvolysis of ammonium vanadate in combination with the photochemical reduction of the products     

FTIR and fluorescence studies on the ground and excited state hydrogen-bonding interactions between 1-methylindole and water in water–triethylamine mixtures

The ground and excited state π-hydrogen-bonding interactions between 1-methylindole, MI, and water have been investigated in water–triethylamine, water–TEA, mixtures. FTIR measurements performed on the OH stretching bands of the water–TEA clusters show that, upon MI addition, the typical bands of the water–TEA system at 3348 cm⁻¹, 3440 cm⁻¹, 3545 cm⁻¹ and 3682 cm⁻¹ diminish, whereas two new absorption bands at 3316 cm⁻¹ and 3654 cm⁻¹ grow up. These spectral changes have been rationalised assuming the formation of only one 1:1 water–MI complex, in which the dangling protons in the water–TEA clusters are hydrogen bonded to the π-cloud of the MI aromatic ring. Steady state and time resolved fluorescence measurements provide additional proofs on the ground state formation of a fluorescent OH ? π hydrogen bonded complex. The relevance that the present and the previously reported results could have on the indole ring photophysics is discussed.     

SCF-CI studies on the electronic ground state of water: Potential energy hypersurface and spectroscopic constants

Large-scale Hartree-Fock self-consistent field calculations, employing extended Gaussian basis sets, and configuration interaction studies are performed to calculate the energy hypersurface of the electronic ground state of the water molecule and to investigate the accuracy requirements in view of the determination of molecular spectroscopic constants. From the calculated points on the hypersurface the theoretical equilibrium geometry, the force field through fourth order, the spectroscopic constants _i, x_ij, _i as well as the Darling-Dennison and Fermi resonance constants are evaluated. The CI surface yields an equilibrium structure for H₂O withr _e = 0.9501 Å and _e=105.33 ° (r _exp = 0.9572 Å and _exp = 104.52 °). The vibrational levels are obtained with a systematic error of about 2 percent and the rotational constants to about 1 percent compared to spectroscopic data. The relative energy maximum corresponding to the linear structure with = is calculated to be 11890cm^–1, within the error limits of the values deduced from experimental measurements.     

On the ground state and first excited state geometries of syn-sesquinorbornene

Extende Hückel calculations on the title compound ($\text{1}$) predict hinge-like bending of the double bond corresponding to interplanar angles of 167° for the ground state and 210° for the first excited state. The predictions are discussed in terms of hyperconjugative interactions.