On heavy metal pollution from a suburban road network

In the context of urban diffuse pollution a suburban road acts as a potential source of toxic pollutants among which heavy metals are very common, are found at elevated concentrations and are generally persistent. With a lack of detailed understanding of metal emission patterns on suburban roads, a detailed study is therefore essential for gaining an improved understanding to plug the knowledge gap in terms of urban diffuse pollution management. The present understanding of pollutant build-up and wash-off processes on road surfaces elucidates that these processes are highly site specific and are hard to generalise in certain aspects. Therefore, this study aimed to characterise heavy metal emissions and associated pollution levels at several road sites on the Riccarton Campus road network using road sediment collected during dry and wet weather periods. The heavy metal concentrations of Cd, Cr, Cu, Ni, Pb and Zn, are believed to be greatly toxic and are highly abundant in road traffic environments, were determined by strong nitric acid digestion and atomic absorption spectrometry. The study revealed that the pollutant build-up and wash-off processes were site specific and so also were the derived local build-up and wash-off parameters, as expected. However, these derived parameters were very different from those used in common urban drainage models suggesting that the default values are (significantly) inappropriate for the studied road network. The quantification of heavy metals in road sediments displayed significantly higher concentrations than local background concentrations. Their concentrations between weather types were found in the order of runoff, snow and dry road sediment, and also varied between sampling sites according to site-specific attributes, such as road lay-out inured traffic movement pattern, road surface condition and presence of road paint rather than due to traffic volume alone. The concentrations of all metals except Pb were significantly higher in finer sediment sizes than in larger sediment sizes. Correlation analyses revealed a similar pattern showing a greater number of statistically significant associations between metals in finer sediment sizes. An assessment of heavy metal contamination indicated that road sediment may likely pose a moderate to considerable level of ecological risk, if transported to the nearby water environment in the study area. The assimilation of the knowledge gained in this study should help to improve current understanding of environmental pollution from suburban roads and to provide better guidance for selecting appropriate control measures under the framework of sustainable urban drainage systems

On certain new notion of order Cauchy sequences, continuity in (l)-group

[EN] In this paper, we introduce the notions of order quasi-Cauchy sequences, downward and upward order quasi-Cauchy sequences, order half Cauchy sequences. Next we consider an associated idea of continuity namely, ward order continuous functions [2] and investigate certain interesting results. The entire investigation is performed in (l)-group setting to extend the recent results in [5, 6].Council of Scientific and Industrial Research, HRDG, IndiaPal, SK.; Chakraborty, S. (2022). On certain new notion of order Cauchy sequences, continuity in (l)-group. Applied General Topology. 23(1):55-68. https://doi.org/10.4995/agt.2022.16126OJS556823

Relativistic coupled-cluster study of RaF as a candidate for parity and time reversal violating interaction

We have employed both Z-vector method and the expectation value approach in the relativistic coupled-cluster framework to calculate the scalar-pseudoscalar (S-PS) P, T -odd interaction constant (W_s) and the effective electric field (Eeff) experienced by the unpaired electron in the ground electronic state of RaF. Further, the magnetic hyperfine structure constants of ^{223}Ra in RaF and ^{223}Ra+ are also calculated and compared with the experimental values wherever available to judge the extent of accuracy obtained in the employed methods. The outcome of our study reveals that the Z-vector method is superior than the expectation value approach in terms of accuracy obtained for the calculation of ground state property. The Z-vector calculation shows that RaF has a high E_eff (52.5 GV/cm) and W_s (141.2 kHz) which makes it a potential candidate for the eEDM experiment.Comment: 8 pages, 3 figure

Relativistic equation-of-motion coupled-cluster method for the electron attachment problem

The article considers the successful implementation of relativistic equation-of-motion coupled cluster method for the electron attachment problem (EA-EOMCC) at the level of single- and double- excitation approximation. The implemented relativistic EA-EOMCC method is employed to calculate ionization potential values of alkali metal atoms (Li, Na, K, Rb, Cs, Fr) and the vertical electron affinity values of LiX (X = H, F, Cl, Br), NaY (Y = H, F, Cl) starting from their closed-shell configuration. Both four-component and exact two-component calculations are done for all the opted systems. Further, we have shown the effect of spin-orbit interaction considering the atomic systems. The results of our atomic calculations are compared with the values from the NIST database and the results are found to be very accurate (< 1 %).Comment: 26 Pages, 3 figures, 6 Tables. Comments are welcom

Electron-nucleus scalar-pseudoscalar interaction in PbF: Z-vector study in the relativistic coupled-cluster framework

The scalar-pseudoscalar interaction constant of PbF in its ground state electronic configuration is calculated using the Z-vector method in the relativistic coupled-cluster framework. The precise calculated value is very important to set upper bound limit on P,T-odd scalar-pseudoscalar interaction constant, k_s, from the experimentally observed P,T-odd frequency shift. Further, the ratio of the effective electric field to the scalar-pseudoscalar interaction constant is also calculated which is required to get an independent upper bound limit of electric dipole moment of electron, d_e, and k_s and how these (d_e and k_s) are interrelated is also presented here.Comment: 6 pages, 1 figure