Assessment of groundwater vulnerability and sensitivity to pollution in Aquifers Zanjan Plain, Iran

Groundwater pollution caused by human activity is a serious environmental problem in cities. Pollution vulnerability assessment of groundwater resources provides information on how to protect areas vulnerable to pollution. The present study is a detailed investigation of the potential for groundwater contamination through construction of a vulnerability map for the study aquifer in Zanjan plain. The parameters used in the DRASTIC model are depth-to-water table, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity. The overlying index, GIS and AHP were used with the modified DRASTIC model to evaluate the vulnerability of the alluvial Zanjan aquifer to nitrates. AHP was used to determine the rate coefficient of each parameter. The correlation coefficients were produced by comparing the vulnerability index with the nitrate concentrations in the groundwater. The results show that the DRASTIC index values for the study area ranged from 82 to 186 and were divided into low, medium, and high vulnerability classes. GIS was found to provide an efficient environment for such analyses. The DRASTIC aquifer vulnerability map indicates the dominance of the medium vulnerability class in the most parts of the study area (49.033%). The high correlation coefficient for the modified DRASTIC index (0.92) and nitrate layer than for the standard DRASTIC model (0.74) suggests that the actual condition in the study area can be better explained by the modified DRASTIC model.Keywords: Groundwater vulnerability, GIS, DRASTIC Model, AHP, Zanja

Biosynthesis of Zinc Oxide Nanoparticles Using Hertia intermedia and Evaluation of its Cytotoxic and Antimicrobial Activities

The unique properties of zinc oxide nanoparticles (ZnO-NPs) produced using plant extract make them attractive for use in medical as well as industrial applications. In this study, ZnO-NPs were synthesized using Hertia intermedia extract as the reducing and stabilizing agent followed by characterization and evaluation of its biological potency. Field emission scanning electron microscopy (FESEM) image showed spherical nanoparticles with a size range of 20�80 nm. UV-vis spectroscopy displayed absorption peaks at 362.67 nm which is one of the characteristic features of ZnO-NPs. FT-IR spectra confirmed the presence of some phytoconstituents as capping agents to stabilize the nanoparticles. MTT assay showed cytotoxicity of ZnO-NPs against Caco-2 (IC50 177 μg/mL), SH-SY5Y (IC50 184 μg/mL), MDA-MB-231 (IC50 168 μg/Ml, and HEK-293 (IC50 240 μg/mL) cell lines. Using 7-dichlorodihydrouorescein diacetate (DCFH-DA) assay, significant production of reactive oxygen species (ROS) was measured after 24 h of treatment with 200 μg/mL ZnO-NPs that is indicative of ZnO-NP-mediated oxidative stress. Induction of apoptosis/necrosis in ZnO-NPs-treated cells was determined using annexin V-PE/7-AAD staining. Furthermore, expression analysis of pro-apoptotic gene Bax and anti-apoptotic gene Bcl-2 by real-time PCR showed 10-fold increase in expression of Bax and 16-fold decrease in expression of Bcl-2 after exposure of cells to ZnO-NPs. Well diffusion method did not show effective antibacterial activities of synthesized ZnO-NPs against both gram-negative and gram-positive bacteria. All the results confirm that the ZnO-NPs synthesized in the present work are a potential candidate to induce ROS and oxidative stress that lead to cytotoxicity in cell lines. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature

Investigation of the effect of water droplet injection on condensation flow of different nozzles geometry

In the present study, the effect of droplet injection of Moore A (MA), and De Laval nozzles (De) on the condensation shock, has been modeled and compared. The Eulerian–Eulerian method has been used in two-dimensional, compressible, viscous, and turbulent using the k−ω SST turbulence model to simulate the condensation flow field numerically. Four different nozzle inlet injection modes are evaluated; droplet injection in all cases caused a weaker condensation shock in the MA nozzle and could eliminate the De nozzle's shock. Also, the Mach number has increased by 2 and 5% at the output of the MA and De nozzles. The droplet spraying does not affect MA nozzle's wetness fraction, but it is reduced by about 30% at the De nozzle output. In general, the results showed that spray droplets at the inlet depend on geometry to improve aerodynamic and thermodynamic parameters. © 2022, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature