Browsing by Author "Dharmendra Kumar Singh"

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Geoelectrical Sounding for Aquifer Characterization in and around Nandgao, Majan, Singrauli District, Madhya Pradesh, India
(Kalpana Corporation, 2022) Dharmendra Kumar Singh; Nawal Kishore; Birendra Pratap; Vijayendra Pratap Dheeraj
Ten geo-electrical soundings using Schlumberger electrode configuration were used to evaluate aquifer geo-elec-tric characteristics in the parts of Nandgao, Majan, district Singrauli, M.P., India. SSR MP-1, a digital resistivity meter, was used for ten vertical electric sounding (VES) sounding with a minimum of 10 m to a maximum of 200 m current electrode (AB) spacing and locating the exact position of VES stations global positioning system (GPS) was used. The IPI2win and win resist software was used for data interpretation, which revealed 3 to 4 subsurface layers comprising the top alluvial soil, sub-soil to fine-grained sandstone, fine-grained sandstone to fractured or weathered sandstone and basement rocks. The resistivity of these strata ranged from 9.55-59.51 ωm, whereas the depth ranged between 0.42-63.91 m. Transverse resistance and longitudinal conductance calculated from the aquifer resistivity and thickness varied from 102.14-4357.44 ωm2 and 0.08-1.02 Siemens, respectively. Also, aquifer resistivity and porosity ranged from 26.95-93.68 ωm and 53-92%, respectively. The low value of trans-missivity at VES location no. 2,3, 5, 8 correspond to low borehole yields and high at VES location no. 1,4, 6, 7, 9, 10 correspond to high borehole yields. The value of overburden protection capacity is low at VES location no. 1, 2, 3, 5, 7, 8 and moderate at VES location 6, which means aquifers contaminants are more vulnerable in these areas. In contrast, at VES location 4, the aquifer protection capacity is high, indicating that the aquifer in these regions is well protected. However, a more significant portion of the study area has a lower value of protective capacities which reveals a more substantial part of the study area is susceptible to contaminants. In general, all of the places may be used to extract groundwater at moderate depths. © 2022 - Kalpana Corporation.
Geoelectrical Sounding to Identify Sub-surface and Groundwater State at Village Banauli, Singrauli District, Madhya Pradesh, India
(Technoscience Publications, 2022) Dharmendra Kumar Singh; Nawal Kishore
Electrical resistivity (Geoelectrical) methods are well-known and common techniques for investigating the groundwater potential zone. These methods are economically viable and have the highest resolving power compared with other geophysical methods. A total of fifteen Vertical electrical soundings were conducted in the village of Banauli, located in Singrauli district in Madhya Pradesh, India. Vertical electrical sounding was carried out using Schlumberger electrode configuration with the maximum current electrode (AB) spacing of 200 m and potential electrode (MN) spacing of 10 m. For interpretation of measured resistivity, the Partial curve matching technique was used to calculate the layer parameters (resistivity and thickness) and further depict the depth section of the profile. In this study, the maximum five-layer model is obtained, and most curves are of HAK types. The first layer has a mean resistivity value of 12.41 Ωm and a mean thickness of 0.94 m. The second layer has mean resistivity of 7.93 Ωm and a mean thickness of 4.79 m. The third layer has a mean thickness value of 10.55 m and a mean resistivity value of 16.54 Ωm. The fourth layer has a mean resistivity value of 20.17 Ωm and a mean thickness of 9.20 m, and finally, the fifth layer, the bedrock, has a higher mean resistivity value of 59.92 Ωm. Thus, the obtained results may be used for identifying the drilling site for the groundwater potential zone. © 2022 Technoscience Publications. All rights reserved.
Relative availability of inorganic N-pools shifts under land use change: An unexplored variable in soil carbon dynamics
(Elsevier B.V., 2016) Pratap Srivastava; Praveen Kumar Singh; Rishikesh Singh; Rahul Bhadouria; Dharmendra Kumar Singh; Shivam Singh; Talat Afreen; Sacchidanand Tripathi; Pardeep Singh; Hema Singh; Akhilesh Singh Raghubanshi
Land use change (LUC) may detrimentally affect the soil organic carbon (SOC) within different soil fractions; directly supplemented by significant contribution to soil CO2 efflux (SCE). To understand the governing mechanism, experimental data were collected for SOC and SCE along with soil physico-chemical, microbial and aggregate characteristics across adjacent secondary forest (SF)-grassland (GL)-cropland (CL) sequence in dry tropical ecosystems. A significant change in SOC and SCE was observed from SF to GL and CL systems, respectively; though moderately from GL to CL system. Respective decrease in SOC (31 and 42%); soil ammonium-N to nitrate-N ratio (ANR; 96 and 86%), microbial biomass C (MBC; 30 and 50%), nitrogen (MBN; 6 and 33%) and MBC/MBN ratio (25 and 24%); whereas increase in SCE (43 and 57%) and soil nitrate-N availability (340 and 592%) was observed from SF to GL and CL systems. Moreover, aggregate physical distribution shifted toward smaller size fractions; whereas aggregate-associated total C and KMnO4-labile-C concentration and carbon management index (CMI) across aggregate-size fractions decreased linearly with the land use sequence. SOC was majorly governed by macro-aggregate water stability (WASmacro) and MBC; whereas SCE by CMI of macro-aggregate (CMImacro) fraction. Furthermore, the ANR showed positive correlation with microbial (i.e. MBC and MBC/MBN ratio) and macro-aggregate physical (i.e. WASmacro) and chemical stability (i.e. CMImacro). It indicates that a shift in the microbial community with the land use may affect the relative availability of inorganic N pools and associated aggregate characteristics. Thus, our results indicate that a shift in ANR with LUC may be an unexplored and crucial indicator of soil C dynamics mediating quantitative and qualitative changes in microbial and aggregate characteristics in dry tropical ecosystems. Further, a critical emphasis is needed on the relationship of SOC dynamics with ANR for future studies at various spatiotemporal scales worldwide to recognize its potential role as ecological indicator of SOC dynamics. Also, its inclusion under climatic models may help to better predict the future climate. © 2016 Elsevier Ltd. All rights reserved.
Why airborne transmission hasn't been conclusive in case of COVID-19? An atmospheric science perspective
(Elsevier B.V., 2021) Kirpa Ram; Roseline C. Thakur; Dharmendra Kumar Singh; Kimitaka Kawamura; Akito Shimouchi; Yoshika Sekine; Hidekazu Nishimura; Sunit K. Singh; Chandra Mouli Pavuluri; R.S. Singh; S.N. Tripathi
Airborne transmission is one of the routes for the spread of COVID-19 which is caused by inhalation of smaller droplets1 containing SARS-CoV-2 (i.e., either virus-laden particulate matter: PM and/or droplet nuclei) in an indoor environment. Notably, a significant fraction of the small droplets, along with respiratory droplets, is produced by both symptomatic and asymptomatic individuals during expiratory events such as breathing, sneezing, coughing and speaking. When these small droplets are exposed to the ambient environment, they may interact with PM and may remain suspended in the atmosphere even for several hours. Therefore, it is important to know the fate of these droplets and processes (e.g., physical and chemical) in the atmosphere to better understand airborne transmission. Therefore, we reviewed existing literature focussed on the transmission of SARS-CoV-2 in the spread of COVID-19 and present an environmental perspective on why airborne transmission hasn't been very conclusive so far. In addition, we discuss various environmental factors (e.g., temperature, humidity, etc.) and sampling difficulties, which affect the conclusions of the studies focussed on airborne transmission. One of the reasons for reduced emphasis on airborne transmission could be that the smaller droplets have less number of viruses as compared to larger droplets. Further, smaller droplets can evaporate faster, exposing SARS-CoV-2 within the small droplets to the environment, whose viability may further reduce. For example, these small droplets containing SARS-CoV-2 might also physically combine with or attach to pre-existing PM so that their behaviour and fate may be governed by PM composition. Thus, the measurement of their infectivity and viability is highly uncertain due to a lack of robust sampling system to separately collect virions in the atmosphere. We believe that the present review will help to minimize the gap in our understanding of the current pandemic and develop a robust epidemiological method for mortality assessment. © 2021 Elsevier B.V.