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Very fast transient overvoltage (VFTO) generated by an operating disconnector is one of the main reasons for electromagnetic disturbance in gas-insulated switchgear (GIS) substations. Generally, the amplitude of VFTO can be used as one of the references for the insulation design of GIS primary electric power equipment, so it is necessary to obtain its accurate amplitude. In this study, a new VFTO measuring sensor is developed and its measurement performance is demonstrated through hundreds of operations by a disconnector in a 220 kV GIS test circuit. The validation shows that the low cut-off frequency of the new VFTO measuring sensor has been greatly expanded to 0.01 mHz, which is improved by about 50% compared with the old sensor. The measurement accuracy of amplitude of VFTO micro-pulse improves greatly by about 80% compared with the old one. Thus, the new VFTO measuring sensor can fully meet the measurement needs of trapped charge voltage, power frequency voltage, and high-frequency transient voltage in VFTO waveform. It can be used to provide more accurate data support for insulation design of GIS primary power electric equipment in extra-high voltage (EHV) and ultra-high voltage (UHV) GIS substations.

This study presents the liquefaction potential in Kahramanmaras city, which is located on the seismically active zones of East Anatolian and Dead Sea Faults in southern central Turkey. Geotechnical investigations in the city were carried out both in situ and laboratory. A total of 238 boreholes in the city were drilled in order to perform Standard Penetration Tests (SPT) and to define the physical properties (sieve analysis, Atterberg limits, soil classification) of the soils obtained from these boreholes. The stratigraphic structure underlying the city consists of various amounts of silt, clay, gravel and sand. Ground water table levels were found to vary from 0-6 m to 15 m or more in the study area. Liquefaction potential was studied based on the SPT results and a hypothetical earthquake with a magnitude of 7.5. The results indicate that the southern areas of the city have a high potential to liquefy, while the northern parts of the city lie mainly within nonliquefaction area. Analyses of liquefaction potential were mapped by using geographical information system (GIS)-based computer software. Evidently, the complied GIS maps could be effectively used by researchers and engineers for further studies on the purpose of land-use planning and urban development.

Rapid identification of groundwater sources is crucial for emergency water supplies. Yudu County (YDC) in Southern China serves as a case study due to its typical mountainous terrain and pressing groundwater demands. To address the limitations of conventional groundwater mapping methods in large-scale areas with sparse data, this study integrates remote sensing (RS), geographic information systems (GIS), and multi-criteria decision analysis (MCDA) techniques to delineate groundwater potential zones (GWPZs) in YDC. Following a series of correlation tests, seven assessment indicators were selected from various groundwater influencing factors, including two innovative ones: terrestrial water storage change (TWSC) and spring flow. The analytic hierarchy process (AHP) and fuzzy AHP (FAHP) models were employed to calculate factor weights, and GWPZ maps were generated using weighted overlay analysis in GIS. The model performance was validated using borewell data, receiver operating characteristic (ROC) curves, and yield prediction models. Additionally, four water enrichment types and their spatial distribution were identified by field investigations and yield prediction assessments. Results indicated a remarkable similarity between GWPZs delineated by AHP and FAHP, categorized into five classes: very high (13.92% for AHP and 14.33% for FAHP), high (26.29 and 27.55%), medium (29.33 and 28.14%), low (20.66 and 21.50%), and very low (9.80 and 8.48%). The area under the curve (AUC) for FAHP was 85.09%, slightly higher than the 84.41% of AHP, while the correlation coefficient (R 2 of the prediction model improved from 0.747 to 0.817 with FAHP. These findings confirmed the reliability of combining GIS and MCDA methods to delineate GWPZs, with FAHP demonstrating an advantage over AHP. The proposed methodology and resulting mapping significantly enhance sustainable water resource management and development in YDC, offering a practical framework for rapid groundwater investigations in disaster response, as well as for long-term water security planning in similar mountainous environments.

Preserving the quality of groundwater has become Bangladesh’s primary challenge in recent years. This study explores temporal trend variations in groundwater quality on a broader scale across 18 stations within the Dhaka division over 35 years. The data set encompasses an analysis of 15 distinct water quality parameters. Modified Mann-Kendal, Sens Slope and Mann-Kendal tests were performed to determine the trend’s variation and slope. In addition, the spatial–temporal changes in the quality of groundwater are studied through Geographic Information System (GIS) mapping and Piper diagram was applied to identify the unique hydrochemical properties. This is the first study conducted on this area using various trends analysis and no in-depth study is available highlighting the trends analysis of groundwater quality on a larger magnitude. In contrast, the correlation matrix reveals a high association between Mg 2+ and SO 4 2− , Na + and Cl − that affects salinity and overall hardness at the majority of sites. The Piper diagram also demonstrates that the groundwater in Madaripur Sadar has major salinity issues. The analysis reveals a distinctive dominance of bicarbonate (HCO 3 − ) ions across all sampling stations, with (HCO 3 − ) equivalent fractions consistently ranging from 0.70 to 0.99 which can cause a significant impact on groundwater uses. This extensive analysis of long-term groundwater quality trends in the Dhaka Division enables researchers to comprehend the overall transition of groundwater quality for hardness related complications in future. Moreover, it can be a baseline study considering the valuable implications and future steps for sustainable water resource management in this region.

Ecological factors that control the species distribution patterns at various spatiotemporal scales will get affected by climate change. To combat the situation, in the past few decades geographical information system (GIS) and remote sensing have been widely used by the researchers in the field of wildlife and habitat suitability modeling. The main objective of this study is to map and predict the current and future habitat suitability potential of Rucervus eldii eldii in Keibul Lamjao National Park (KLNP) using MaxEnt. Presence location data of the species, topographic factors, and bio-climatic variables were used as input in the MaxEnt software to map current habitat suitability potential. To map the habitat suitability potential for future, two representative concentration pathway (RCP) scenarios RCP 2.6 and RCP 8.5 for the years 2050 and 2070 were used. The model returned an average AUC value of 0.944 which indicates the model to be sensitive and descriptive. Isothermality and precipitation in the wettest quarter were found to be two most significant variables. The suitable range of precipitation in the wettest quarter for Rucervus eldii eldii varies from 1365 to 1410 mm with an optimal value of 1405 mm and isothermality from 46.43 to 46.6% with an optimal value of 46.5%. Current habitat suitability results of the model show 0.45 km 2 of the area under no potential, 29.25 km 2 of the area under least potential, 8.29 km 2 of the area under moderate potential, 9.21 km 2 of the area under good potential, and 8.82 km 2 of the area under high potential. Both RCPs for the years 2050 and 2070 show the decreasing trend in the area under high suitability potential and increasing trend under no suitability potential. The results of this study can provide aid in the management and protection of Rucervus eldii eldii .

Under operating conditions, metallic particle contaminants inside Gas-Insulated Switchgears (GIS) represent a major threat that can initiate partial discharges (PD) and lead to insulation failure. To investigate the discharge patterns under combined AC and switching impulse voltages, this paper presents an experimental study conducted in SF6 gas on wire-shaped, spherical, and Mixed Metal Particles. By synchronously analyzing PD time-domain waveforms, Phase-Resolved Partial Discharge (PRPD) patterns, and high-speed motion camera recordings, the correlation between particle motion behavior and discharge signals was systematically examined. The results indicate that wire particles exhibit a significant discharge initiation delay under the combined voltage; however, intense, discrete discharges with large magnitudes occur during their vertical jumping phase. In contrast, spherical particles can be activated within the first power frequency cycle without delay, but the subsequent discharge magnitudes are limited. The characteristics of hybrid particles lie between these two types, demonstrating a staged evolution described as “spherical particles lead initiation, wire particles dominate discharge.” Furthermore, under the sustained AC voltage, hybrid particles trigger a more dispersed and violent discharge process. These findings reveal the complex motion-discharge mechanism of Mixed Metal Particles, providing critical insights for fault mechanism analysis and insulation protection related to particle contamination in practical GIS equipment.

Groundwater resources are used in various parts of the world to meet out drinking water supply, irrigational practices and industrial applications. These valuable resources are naturally replenished by rainfall infiltration. Due to population growth and industrialization, groundwater resources are often overexploited in different parts of the world particularly in the hard rock areas. It leads to rapid declination in the groundwater level. Therefore, groundwater fluctuation with respect to space and time governs attention throughout the world for the purpose of sustainable management of water resources. In the present study, long-term trend detection and spatiotemporal variation of groundwater levels were analyzed using Geographical Information System (GIS) and performing statistical tests for the Lower Bhavani River basin, Tamil Nadu, India. For this purpose, 32 years long-term groundwater-level data (1984–2015) of 57 observation wells spread over the study area were collected from the government departments. Seasonal variation of groundwater levels was plotted spatially for pre-monsoon (March to May), post-monsoon (January and February), southwest (SW) monsoon (June to September) and northeast (NE) monsoon (October to December) seasons using GIS. The trend variation of groundwater levels was predicted by performing statistical tests such as Mann–Kendall test and Sen’s slope estimator. The present study indicates that the average annual groundwater level has lowered beyond 15 m (below ground level) during all the monsoon seasons in the year 2003 and 2004, which highlights less rainfall infiltration and overexploitation of groundwater. This leads the hard rock aquifer into stress. The study also shows that the groundwater fluctuation is very high in the southeastern and northeastern parts of the basin, and it is moderate in the northern and northwestern parts of the basin. However, the fluctuation is comparatively less in the central part of the basin because of replenishment of groundwater by the Bhavani River. The trend analysis highlights that declining water table is mostly found during SW monsoon season (summer season), which is observed more than 50% area of the basin. The places such as Emmampoondi, Kumbapanai, Kandisalai, Alukuli, Perikoduveri, P.Mettupalayam, Pudupalayam, Sathyamangalam, Nallagoundanpudur, Kullampalayam and Baguthampalayam are mostly affected by the declining trend in the groundwater level. Therefore, this study recommends for the implementation of large-scale rainwater harvesting system in the Lower Bhavani River basin to augment groundwater resources.

Groundwater is a vital water source in the rural and urban areas of developing and developed nations. In this study, a novel hybrid integration approach of Fisher’s linear discriminant function (FLDA) with rotation forest (RFLDA) and bagging (BFLDA) ensembles was used for groundwater potential assessment at the Ningtiaota area in Shaanxi, China. A spatial database with 66 groundwater spring locations and 14 groundwater spring contributing factors was prepared; these factors were elevation, aspect, slope, plan and profile curvatures, sediment transport index, stream power index, topographic wetness index, distance to roads and streams, land use, lithology, soil and normalized difference vegetation index. The classifier attribute evaluation method based on the FLDA model was implemented to test the predictive competence of the mentioned contributing factors. The area under curve, confidence interval at 95%, standard error, Friedman test and Wilcoxon signed-rank test were used to compare and validate the success and prediction competence of the three applied models. According to the achieved results, the BFLDA model showed the most prediction competence, followed by the RFLDA and FLDA models, respectively. The resulting groundwater spring potential maps can be used for groundwater development plans and land use planning.

Groundwater is one of the most valuable natural resources, which supports human health, economic development and ecological diversity. Overexploitation and unabated pollution of this vital resource is threatening our ecosystems and even the life of future generations. With the advent of powerful personal computers and the advances in space technology, efficient techniques for land and water management have evolved of which RS (remote sensing) and GIS (geographic information system) are of great significance. These techniques have fundamentally changed our thoughts and ways to manage natural resources in general and water resources in particular. The main intent of the present paper is to highlight RS and GIS technologies and to present a comprehensive review on their applications to groundwater hydrology. A detailed survey of literature revealed six major areas of RS and GIS applications in groundwater hydrology: (i) exploration and assessment of groundwater resources, (ii) selection of artificial recharge sites, (iii) GIS-based subsurface flow and pollution modeling, (iv) groundwater-pollution hazard assessment and protection planning, (v) estimation of natural recharge distribution, and (vi) hydrogeologic data analysis and process monitoring. Although the use of these techniques in groundwater studies has rapidly increased since early nineties, the success rate is very limited and most applications are still in their infancy. Based on this review, salient areas in need of further research and development are discussed, together with the constraints for RS and GIS applications in developing nations. More and more RS- and GIS-based groundwater studies are recommended to be carried out in conjunction with field investigations to effectively exploit the expanding potential of RS and GIS technologies, which will perfect and standardize current applications as well as evolve new approaches and applications. It is concluded that both the RS and GIS technologies have great potential to revolutionize the monitoring and management of vital groundwater resources in the future, though some challenges are daunting before hydrogeologists/hydrologists.

Twenty eight surface water samples were collected from fourteen sites of the West Bokaro coalfield, India. The concentration of Mn, Cu, Zn, Ni, As, Se, Al, Cr, Ba, and Fe were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) for determination of seasonal fluctuations and a heavy metal pollution index (HPI). The HPI values were below the critical pollution index value of 100. Metal concentrations were higher in the pre-monsoon season as compared to the post-monsoon season. The Zn, Ni, Mn, As, Se, Al, Ba, Cu, and Cr concentrations did not exceed the desirable limits for drinking water in either season. However, at many sites, concentrations of Fe were above the desirable limit of the WHO ( 2006 ) and Indian drinking water standard (BIS 2003 ) in both seasons. The water that contained higher concentrations of Fe would require treatment before domestic use.