Geochemical Conditions Affecting Uranium(VI) Fate And Transport In Soil And Groundwater In The Presence Of Phosphate

Soil and groundwater contamination with actinides like uranium is a serious environmental concern. Phosphate addition to uranium-contaminated soil and groundwater can potentially provide long-term in-situ U(VI) immobilization by precipitation of low solubility U(VI)-phosphates. Reactions at the iron: oxy)hydroxide-water interface can control macroscopic transport and long-term stability of uranium. First, the interactions among phosphate, U(VI), and goethite: alpha-FeOOH) were investigated in a year-long batch experimental study. Dissolved U(VI) and phosphate concentrations were interpreted within a reaction-based modeling framework. U(VI) uptake mechanism varied with the aqueous composition. For most initially supersaturated conditions, chernikovite, H3O(UO2)(PO4)*3H2O(s), nucleated homogeneously, but heterogeneous nucleation probably occurred in cases of mild supersaturation. For conditions undersaturated with respect to chernikovite, phosphate-enhanced U(VI) adsorption indicated the formation of a U(VI)-phosphate-Fe(III) oxide ternary surface complex. Second, molecular-scale structures of adsorbed and precipitated U(VI) from batch experiments were probed using X-ray absorption fine-structure: XAFS) spectroscopy for different total U(VI) concentrations over a pH range 4-7 in the absence and presence of phosphate. The structure of precipitated U(VI) fit the meta-autunite group structure. While U(VI) adsorbed as bidentate edge-sharing =Fe(OH)2UO2 and bidentate corner-sharing: =FeOH)2UO2 surface complexes in the absence of phosphate, it formed a ternary surface complex: =FeO)2UO2PO4 in the presence of phosphate. Third, the effect of transport on U(VI) uptake and remobilization mechanisms and rate was examined. Continuous-flow stirred tank reactor: CFSTR) experiments at pH 4 were conducted under conditions supersaturated and undersaturated with respect to chernikovite and analyzed using a combination of measured dissolved concentrations, microscopy, and XAFS spectroscopy. The rates of dominant U(VI) and phosphate uptake and remobilization mechanisms in the absence and presence of goethite were quantified using a flow-through reactor model. Finally, the effects of simultaneous Fe(III) uptake on iron: oxy)(hydr)oxides on U(VI) and phosphate uptake and remobilization were investigated at pH 4. Goethite-coated sand packed columns and goethite-containing CFSTRs were used to simulate environmental conditions favoring the growth of iron: oxy)(hydr)oxide. While the presence of co-influent Fe(III) increased the extent and rate of phosphate uptake its presence not only decreased U(VI) uptake on goethite but also limited the formation of stable phosphate-induced uranium surface species

Defluoridation of water using Alum impregnated brick powder and its comparison with brick powder

Abstract-The batch study process was adopted to study the defluoridation of water using alum impregnated on brick powder. Different adsorption parameters, viz. effect of pH, effect of dose and contact time were selected and their optimization was done for the study. Alum and brick, when used individually are effective materials to cause defluoridation of water. But both the materials have certain limitations. Comparison of adsorption by Alum impregnated brick powder was made with adsorption by brick powder. In the optimum condition of pH and dose of adsorbents, the percentage defluoridation from synthetic sample for Alum impregnated on brick powder was found to be 4.0-5.0 % higher than the defluoridation due to brick powder. The test was performed on synthetic water prepared by using public supply water. The water contained very little other impurities. Presence of other ions in synthetic water did not significantly affect the defluoridation efficiency of Alum impregnated brick powder. The optimum pH range for the material was found to be 6.0-8.0 and adsorption equilibrium was found to be 60 min. These conditions make it very suitable for use in drinking water treatment. Defluoridation capacity of Alum impregnated brick powder can be explained on the basis of the chemical interaction of fluoride with the metal oxides under suitable pH conditions. The adsorption process was found to follow first order rate mechanism as well as Langmuir isotherm. Index terms: Defluoridation; Adsorption; Brick powder (BP); Alum impregnated on brick powder (AIBP)

A CME Source Region Catalogue and their Associated Properties

The primary objective of this study is to connect the coronal mass ejections (CMEs) to their source regions, primarily creating a CME source region (CSR) catalogue, and secondly probing into the influence the source regions have on different statistical properties of CMEs. We create a source region catalogue for 3327 CMEs from 1998 to 2017, thus capturing the different phases of cycle 23 and 24. The identified source regions are segregated into 3 classes, Active Regions (ARs), Prominence Eruptions (PEs) and Active Prominences (APs), while the CMEs are segregated into slow and fast based on their average projected speeds. We find the contribution of these three source region types to the occurrences of slow and fast CMEs to be different in the above period. A study of the distribution of average speeds reveals different power-laws for CMEs originating from different sources, and the power-law is different during the different phases of cycles 23 and 24. A study of statistical latitudinal deflections showed equator-ward deflections, while the magnitude of deflections again bears an imprint of the source regions. An East-West asymmetry is also noted, particularly in the rising phase of cycle 23, with the presence of active longitudes for the CMEs, with a preference towards the Western part of the Sun. Our results show that different aspects of CME kinematics bear a strong imprint of the source regions they originate from, thus indicating the existence of different ejection and/or propagation mechanisms of these CMEs.Comment: 29 Pages, 18 Figures. Accepted in The Astrophysical Journal Supplement Series (APJS

SMART GRID ENABLES DEREGULATED POWER SECTOR

This paper provides an overview of the role of Smart-grid in deregulated power sector. This includes the architecture and key feature of smart grid with Advantages, disadvantages and challenges to its adoption in the deregulated power sector. In the Deregulated power sector need of division between generation, transmission and distribution. Due to this market monopoly will be end and actual cost of power will be paid. For the calculation of actual data there is a need of real time data of consumption, generation and consumption. The accelerating installation of renewable electrical power generation has made the lot of requirement for a restructured electrical power system design. On the basis of specific configurations, particular rules and regulation it will then need to be improved. The Smart-grids can meet the price, efficient result, and environmental improvement; and the demand requirements for security, quality, reliability, and availability benefits of location generation, achieved by modern controls and operating. This will also useful for the reduction of CO2 emission. In the deregulated power sector all the calculation of cost depend on the real time data which can be obtained by smart meters and other components of smart grid

CALCULATIONS OF ELECTRICAL POWER COST IN RESTRUCTURED POWER SECTOR: A CASE STUDY

This paper presents different methods for electrical cost of transmission and distribution to its customer through different transactions under restructured environment of Electrical power sector. There are different methods for calculate the cost on the basis of various criteria. In this paper explanation of different methods is given and tries to explain the best of them. There is IEEE 9 bus system is considered for the calculations. For the calculation of rate some transaction assumed on different buses and load is taken. This transaction is used in Megawatt. These transactions are bilateral and free from the direction of power flow direction, reactive and active power both are considered and power factor of the system included. Calculation of the flowing power at the different busses using load flow has been calculated. Load flow calculation provide power flow in transmission line and this power can use for the calculation of the cost of transmission power. After that we can calculate the price of electricity with different transaction on different values and without transaction. Auction system or mechanism is used in restructured electrical power sector for transparent and better than other way to calculate electricity cost

Thermal Radiation from Compact Objects in Curved Space-Time

We highlight here the fact that the distantly observed luminosity of a spherically symmetric compact star radiating thermal radiation isotropically is higher by a factor of (1+zb)2 compared to the corresponding flat space-time case, where zb is the surface gravitational redshift of the compact star. In particular, we emphasize that if the thermal radiation is indeed emitted isotropically along the respective normal directions at each point, this factor of increment (1+zb)2 remains unchanged even if the compact object would lie within its photon sphere. Since a canonical neutron star has zb≈0.1, the actual X-ray luminosity from the neutron star surface could be ∼20% higher than what would be interpreted by ignoring the general relativistic effects described here. For a static compact object, supported by only isotropic pressure, compactness is limited by the Buchdahl limit zb<2.0. However, for compact objects supported by anisotropic pressure, zb could be even higher (zb<5.211). In addition, in principle, there could be ultra-compact objects having zb≫1. Accordingly, the general relativistic effects described here might be quite important for studies of thermal radiation from some ultra-compact objects

Thermal Radiation from Compact Objects in Curved Space-Time

We highlight here the fact that the distantly observed luminosity of a spherically symmetric compact star radiating thermal radiation isotropically is higher by a factor of (1+zb)2 compared to the corresponding flat space-time case, where zb is the surface gravitational redshift of the compact star. In particular, we emphasize that if the thermal radiation is indeed emitted isotropically along the respective normal directions at each point, this factor of increment (1+zb)2 remains unchanged even if the compact object would lie within its photon sphere. Since a canonical neutron star has zb≈0.1, the actual X-ray luminosity from the neutron star surface could be ∼20% higher than what would be interpreted by ignoring the general relativistic effects described here. For a static compact object, supported by only isotropic pressure, compactness is limited by the Buchdahl limit zb2.0. However, for compact objects supported by anisotropic pressure, zb could be even higher (zb5.211). In addition, in principle, there could be ultra-compact objects having zb≫1. Accordingly, the general relativistic effects described here might be quite important for studies of thermal radiation from some ultra-compact objects

Practices and attitudinal behavior about drinking water in an urban slum of district Rohtak, Haryana: A community-based study

Background: Globally, approximately, one billion people lack access to safe drinking water and 1.59 million deaths per year are because of contaminated water, primarily in children age <5 years. WHO reported that more than 90% of diarrhea cases can be prevented by enhancing the availability of clean water and improving hygiene measures. Methodology: The study was conducted in an urban slum of Rohtak district. Investigator interviewed the mothers at their home having children age less than 5 years using study tools in their vernacular language. Study Design: The study was a community based epidemiological study with cross-sectional design. Study Participants: 400 mothers having children less than 5 years. Results: Most of subjects (59%) were in the age group of 15-25 years followed by in 25-35 years. One third of subjects belonged to upper caste and 29% of subjects from backward class. The study found that 80% of mother store water in earthen pitcher followed by plastic jug (14%). 78% of mothers said that their source of drinking water was tap while 12% had Hand pump. 83.5% of subjects said that they drink water as such ie without filtering, boiling or chlorination. Conclusion and Recommendations: The study concluded that the prevalence of diarrhea is more among children < 5 years this is because of poor knowledge, poor attitude and inadequate storage water practices of water. The study recommends creating awareness how to diminish contamination of water at household level, creating community groups for women to learn about treatment of water at household level

Environmental status of groundwater affected by chromite ore processing residue (COPR) dumpsites during pre-monsoon and monsoon seasons

Chromite ore processing residue (COPR) is generated by the roasting of chromite ores for the extraction of chromium. Leaching of carcinogenic hexavalent chromium (Cr(VI)) from COPR dumpsites and contamination of groundwater is a key environmental risk. The objective of the study was to evaluate Cr(VI) contamination in groundwater in the vicinity of three COPR disposal sites in Uttar Pradesh, India, in the pre-monsoon and monsoon seasons. Groundwater samples (n = 57 pre-monsoon, n = 70 monsoon) were taken in 2014 and analyzed for Cr(VI) and relevant hydrochemical parameters. The site-specific ranges of Cr(VI) concentrations in groundwater were <0.005 to 34.8 mg L-1 (Rania), <0.005 to 115 mg L-1 (Chhiwali), and <0.005 to 2.0 mg L-1 (Godhrauli). Maximum levels of Cr(VI) were found close to the COPR dumpsites and significantly exceeded safe drinking water limits (0.05 mg L-1). No significant dependence of Cr(VI) concentration on monsoons was observed