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Integrated Geological and Geophysical Mapping for Groundwater Potential Studies at Ekwegbe-Agu and Environs, Enugu State, Nigeria
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作者 Charles Chibueze Ugbor Ugochukwu Kingsley Ogbodo Osita Kelechi Eze 《Open Journal of Geology》 CAS 2024年第4期513-547,共35页
The study integrates both the geological and geophysical mapping techniques for groundwater potential studies at Ekwegbe-Agu and the environs, Enugu state, Nigeria for optimal citing of borehole. Located in the Anambr... The study integrates both the geological and geophysical mapping techniques for groundwater potential studies at Ekwegbe-Agu and the environs, Enugu state, Nigeria for optimal citing of borehole. Located in the Anambra Basin between latitudes 6˚43'N and 6˚47'N and longitudes 7˚28'E and 7˚32'E, it is stratigraphycally underlain by, from bottom to top, the Enugu/Nkporo, Mamu and Ajali Formation respectively, a complex geology that make citing of productive borehole in the area problematic leading to borehole failure and dry holes due to inadequate sampling. The study adopted a field and analytic sampling approach, integrating field geological, electrical resistivity and self-potential methods. The software, SedLog v3.1, InterpexIx1Dv.3, and Surfer v10 were employed for the data integration and interpretation. The result of the geological field and borehole data shows 11 sedimentary facies consisting of sandstone, shales and heterolith of sandstone/shale, with the aquifer zone mostly prevalent in the more porous sand-dominated horizons. Mostly the AK and HK were the dominant curve types. An average of 6 geo-electric layers were delineated across all transects with resistivity values ranging from 25.42 - 105.85 Ωm, 186.38 - 3383.3 Ωm, and 2992 - 6286.4 Ωm in the Enugu, Mamu and Ajali Formations respectively. The resistivity of the main aquifer layer ranges from 1 to 500 Ωm. The aquifer thickness within the study area varies between 95 and 140 m. The western and northwestern part of the study area which is underlain mainly by the Ajali Formation showed the highest groundwater potential in the area and suitable for citing productive boreholes. 展开更多
关键词 SEISMIC Ekwegbe-Agu groundwater RESISTIVITY Field Mapping Borehole Logging
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Call for Papers——Feature Topic Vol.22,No.3,2025 Special Issue of China Communications:Convergence of 6G empowered Edge Intelligence and Generative AI:Theories,Algorithms,and Applications
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《China Communications》 SCIE CSCD 2024年第1期F0003-F0003,共1页
Generative artificial intelligence(AI),as an emerging paradigm in content generation,has demonstrated its great potentials in creating high-fidelity data including images,texts,and videos.Nowadays wireless networks an... Generative artificial intelligence(AI),as an emerging paradigm in content generation,has demonstrated its great potentials in creating high-fidelity data including images,texts,and videos.Nowadays wireless networks and applications have been rapidly evolving from achieving“connected things”to embracing“connected intelligence”.Generative AI has been recognized as a fundamentally innovative technology to drive the advancement of intelligent wireless communications and networks. 展开更多
关键词 CONNECTED convergence networks
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Diagnostic values of questionnaires of Convergence Insufficiency Symptom Survey and College of Optometrists Vision Development Quality of Life in the screening of convergence insufficiency
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作者 Ling Xiong Qian Chen Ye Wu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第5期904-908,共5页
AIM:To compare and analyse the diagnostic efficacy of the College of Optometrists Vision Development Quality of Life Questionnaire(COVD-QOL)and the Convergence Insufficiency Symptom Survey(CISS)in detecting convergenc... AIM:To compare and analyse the diagnostic efficacy of the College of Optometrists Vision Development Quality of Life Questionnaire(COVD-QOL)and the Convergence Insufficiency Symptom Survey(CISS)in detecting convergence insufficiency and to compare their diagnostic value in clinical applications.METHODS:Using the diagnostic test method,62 adult patients with convergence insufficiency(age:24.74±3.75y)and 62 normal participants(age:23.61±3.13y)who visited the Optometry Clinic of West China Hospital of Sichuan University from April 2021 to January 2023 were included.All subjects completed the CISS and COVD-QOL.Statistical analysis of the sensitivity and specificity of the CISS and COVD-QOL and comparison and joint experimental analysis of their diagnostic efficacy were performed.RESULTS:The sensitivity of the CISS and COVD-QOL for convergence insufficiency was 64.5%and 71.0%,respectively,while the specificity was 96.8%and 67.7%,respectively.Compared to the CISS alone,the combination of the CISS and COVD-QOL demonstrated lower sensitivity and specificity.The areas under the receiver operating characteristic curve of CISS,COVD-QOL and CISS combined with COVD-QOL were 0.806,0.694 and 0.782,respectively.CONCLUSION:Considering the low sensitivity of the CISS and the low specificity of the COVD-QOL,it is recommended to supplement these questionnaires with other screening tests for the detection of convergence insufficiency. 展开更多
关键词 convergence insufficiency symptom survey College of Optometrists Vision Development Quality of Life Questionnaire convergence insufficiency ASTHENOPIA
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Exploring groundwater quality in semi-arid areas of Algeria:Impacts on potable water supply and agricultural sustainability
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作者 Noua ALLAOUA Hinda HAFID Haroun CHENCHOUNI 《Journal of Arid Land》 SCIE CSCD 2024年第2期147-167,共21页
Groundwater quality assessment is important to assure safe and durable water use.In semi-arid areas of Algeria,groundwater represents the main water resource for drinking water supply of the rural population as well a... Groundwater quality assessment is important to assure safe and durable water use.In semi-arid areas of Algeria,groundwater represents the main water resource for drinking water supply of the rural population as well as for irrigation of agricultural lands.Groundwater samples from wells and springs were collected from the Gargaat Tarf and Annk Djemel sub-watersheds of the Oum El Bouaghi,Algeria,and were analyzed and compared with the World Health Organization(WHO)standards.Results showed that most of the measured physical and chemical parameters exceeded the quality limits according to the WHO standards.Groundwater had a slightly alkaline water pH(7.00-7.79),electrical conductivity>1500μS/cm,chloride>500 mg/L,calcium>250 mg/L,and magnesium>155 mg/L.Water quality index(WQI)results showed that 68%of the area had excellent water quality,24%of the samples fell into good category,and only 8%were of poor quality and unsuitable for human consumption.Six wells in the area showed bacterial contamination.Total coliforms(453.9(±180.3)CFU(colony-forming units)/100 mL),fecal coliforms(243.2(±99.2)CFU/100 mL),and fecal streptococci(77.9(±32.0)CFU/100 mL)loads were above the standard limits set by the WHO.These results confirmed that water resources in the study area were strongly influenced by anthropogenic activities and were not recommended for consumption as drinking water. 展开更多
关键词 bacteriological indicator groundwater WATERSHED physical-chemical parameter water quality index
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Pumping-induced Well Hydraulics and Groundwater Budget in a Leaky Aquifer System with Vertical Heterogeneity in Aquitard Hydraulic Properties
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作者 ZHUANG Chao LÜChenyang +5 位作者 YAN Long LI Yabing ZHOU Zhifang WANG Jinguo DOU Zhi Walter A.ILLMAN 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第2期477-490,共14页
In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is... In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is derived for pumping-induced well hydraulics and groundwater budget with consideration of vertical heterogeneity in aquitard hydraulic conductivity(K)and specific storage(S_(s)).The proposed new solution is innovative in its partitioning of the aquitard into multiple homogeneous sub-layers to enable consideration of various forms of vertically heterogeneous K or S_(s).Two scenarios of analytical investigations are explored:one is the presence of aquitard interlayers with distinct K or S_(s) values,a common field-scale occurrence;another is an exponentially depth-decaying aquitard S_(s),a regional-scale phenomenon supported by statistical analysis.Analytical investigations reveal that a low-K interlayer can significantly increase aquifer drawdown and enhance aquifer/aquitard depletion;a high-S_(s) interlayer can noticeably reduce aquifer drawdown and increase aquitard depletion.Locations of low-K or high-S_(s) interlayers also significantly impact well hydraulics and groundwater budget.In the context of an exponentially depth-decaying aquitard S_(s),a larger decay exponent can enhance aquifer drawdown.When using current models with a vertically homogeneous aquitard,half the sum of the geometric and harmonic means of exponentially depth-decaying aquitard S_(s) should be used to calculate aquitard depletion and unconfined aquifer leakage. 展开更多
关键词 HYDROGEOLOGY AQUITARD vertical heterogeneity semi-analytical solution well hydraulics groundwater budget
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Assessment of groundwater quantity, quality, and associated health risk of the Tano river basin, Ghana
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作者 Adwoba Kua-Manza Edjah Bruce Banoeng-Yakubo +6 位作者 Anthony Ewusi Enoch Sakyi-Yeboah David Saka Clara Turetta Giulio Cozzi David Atta-Peters Larry Pax Chegbeleh 《Acta Geochimica》 EI CAS CSCD 2024年第2期325-353,共29页
In the Tano River Basin,groundwater serves as a crucial resource;however,its quantity and quality with regard to trace elements and microbiological loadings remain poorly understood due to the lack of groundwater logs... In the Tano River Basin,groundwater serves as a crucial resource;however,its quantity and quality with regard to trace elements and microbiological loadings remain poorly understood due to the lack of groundwater logs and limited water research.This study presents a comprehensive analysis of the Tano River Basin,focusing on three key objectives.First,it investigated the aquifer hydraulic parameters and the results showed significant spatial variations in borehole depths,yields,transmissivity,hydraulic conductivity,and specific capacity.Deeper boreholes were concentrated in the northeastern and southeastern zones,while geological formations,particu-larly the Apollonian Formation,exhibit a strong influence on borehole yields.The study identified areas with high transmissivity and hydraulic conductivity in the southern and eastern regions,suggesting good groundwater avail-ability and suitability for sustainable water supply.Sec-ondly,the research investigated the groundwater quality and observed that the majority of borehole samples fall within WHO(Guidelines for Drinking-water Quality,Environmental Health Criteria,Geneva,2011,2017.http://www.who.int)limit.However,some samples have pH levels below the standards,although the groundwater generally qualifies as freshwater.The study further explores hydrochemical facies and health risk assessment,highlighting the dominance of Ca–HCO3 water type.Trace element analysis reveals minimal health risks from most elements,with chromium(Cr)as the primary contributor to chronic health risk.Overall,this study has provided a key insights into the Tano River Basin’s hydrogeology and associated health risks.The outcome of this research has contributed to the broader understanding of hydrogeologi-cal dynamics and the importance of managing groundwater resources sustainably in complex geological environments. 展开更多
关键词 groundwater Unsupervised machine learning technique HYDROCHEMISTRY Aquifer hydraulic parameter Health risk
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Assessment of Groundwater Physico-Chemical Quality in the Ouémé Delta (Southern-Benin)
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作者 Aoulatou Alassane Zakari Dadja Toyou Masamaéya Gnazou +5 位作者 Abdoukarim Alassane Kodjo Apelete Raoul Kpegli Ousmane Touré Boukari Bio Guidah Chabi Bénito Didier Koukpohounsi Daouda Mama 《Journal of Environmental Protection》 2024年第3期298-317,共20页
Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural ... Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural and industrial activities have resulted in a deterioration in the quality of these resources. To assess the quality of the delta’s groundwater and its suitability for human consumption and irrigation, a total of fourteen (14) physico-chemical parameters were analyzed in some forty existing water points between September 2020 and March 2021, using standard water analysis techniques. The values obtained were compared with the potability standards recommended by the World Health Organization (WHO) and the Republic of Benin and were subjected to statistical analysis (principal component analysis (PCA)). In addition, methods for determining the suitability of water for irrigation were used. The results showed that the waters are acidic to slightly neutral and influenced by ambient temperature. In addition, the waters are moderately mineralized, with conductivities (24 - 1205 μS/cm) in line with WHO standards. A comparison of the analytical results of the WHO (2017) and Benin (2001) standards indicates that the majority of the waters studied are of good quality for all the chemical parameters considered. Nevertheless, some samples show levels of nitrates (21%), potassium (14% to 16%), calcium (13%), ammonium (12%), nitrites (8%) and bicarbonates (10%) over their respective standards. The Wilcox and Riverside diagrams indicate that the majority of waters (90%) have excellent suitability for irrigation and no negative effect on soil fertilization. 展开更多
关键词 BENIN OuéméDelta groundwater Physico-Chemical Quality Consumption IRRIGATION
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Spatial Differentiation and Convergence Trend of High-quality Development Level of China’s Tourism Economy
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作者 CAO Shanshan HE Zhaoli +2 位作者 NIU Jinlan WANG Songmao ZHAO Lei 《Chinese Geographical Science》 SCIE CSCD 2024年第2期230-249,共20页
This paper aims to interpret the connotation of high-quality development of tourism economy(HQTE)from the perspective of the new development concepts of innovation,coordination,green,openness and sharing,and then to e... This paper aims to interpret the connotation of high-quality development of tourism economy(HQTE)from the perspective of the new development concepts of innovation,coordination,green,openness and sharing,and then to evaluate the spatial differenti-ation of China’s HQTE based on provincial panel data from 2009 to 2018.Specifically,we employ the spatial convergence model to ex-plore the absolute and conditionalβconvergence trends of HQTE in the whole country and the eastern,central and western regions of China.Our empirical results reveal that:1)within the decade,from 2009 to 2018,regions of China with the highest HQTE index is its eastern region followed by the central region and then the western region,but the fastest growing one is the western region of China fol-lowed by the central region and then the eastern region.2)Whether or not the spatial effect is included,there are absolute and condition-alβconvergence in HQTE in the whole country and aforementioned three regions.3)The degree of government attention as well as the level of economic development and location accessibility are the positive driving factors for the convergence of HQTE in the whole country and the three regions.The degree of marketization and human capital have not passed the significance test either in the whole country or in the three regions.The above conclusions could deepen the understanding of the regional imbalance and spatial conver-gence characteristics of HQTE,clarify the primary development objects,and accomplish the goal of China’s HQTE. 展开更多
关键词 new development concepts high-quality development of tourism economy(HQTE) spatial convergence China
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Groundwater vulnerability assessment using a GIS-based DRASTIC method in the Erbil Dumpsite area (Kani Qirzhala), Central Erbil Basin, North Iraq
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作者 Masoud H Hamed Rebwar N Dara Marios C Kirlas 《Journal of Groundwater Science and Engineering》 2024年第1期16-33,共18页
Groundwater vulnerability assessment is a crucial step in the efficient management of groundwater resources,especially in areas with intensive anthropogenic activities and groundwater pollution.In the present study,th... Groundwater vulnerability assessment is a crucial step in the efficient management of groundwater resources,especially in areas with intensive anthropogenic activities and groundwater pollution.In the present study,the DRASTIC method was applied using Geographic Information System(GIS)to delineate groundwater vulnerability zones in the Erbil Dumpsite area,Central Erbil Basin,North Iraq.Results showed that the area was classified into four vulnerability classes:Very low(16.97%),low(27.67%),moderate(36.55%)and high(18.81%).The southern,south-eastern and northern parts of the study area exhibited the highest vulnerability potential,while the central-northern,northern and north-western regions displayed the lowest vulnerability potential.Moreover,results of the single-parameter sensitivity analysis indicated that amongst the seven DRASTIC parameters,the unsaturated zone and the aquifer media were the most influencing parameters.In conclustion,the correlation of 25 nitrate concentration values with the final vulnerability map,assessed using the Pearson correlation coefficient,yielded a satisfactory result of R=0.72. 展开更多
关键词 DRASTIC Erbil Iraq groundwater vulnerability assessment NITRATE POLLUTION Sensitivity analysis
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The Damaging Effects of Abstracting the Deep Aquifers’Groundwater in Jordan-Quality Constraints
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作者 Elias Salameh Ghaida Abdallat Taleb Odeh 《Journal of Geoscience and Environment Protection》 2024年第3期250-278,共29页
The deep aquifers in Jordan contain non-renewable and fossil groundwater and their extraction is quasi a mining process, which ends in the depletion of these resources. Although aquifers in the majority of groundwater... The deep aquifers in Jordan contain non-renewable and fossil groundwater and their extraction is quasi a mining process, which ends in the depletion of these resources. Although aquifers in the majority of groundwater basins in Jordan are vertically and horizontally interconnected stratification in different water quality horizons with generally increasing water salinity with the depth is observed. Many officials and planners advocate the extraction of deep salty and brackish water to be desalinated and used in household, industrial, and agricultural uses. In this article, the quality of the groundwater in the different deep aquifers and areas in Jordan is discussed. The results of this study show that the consequences of the deep groundwater exploitation are not restricted to depletion of the deep aquifers but also that the overlying fresh groundwater will, due to vertical and horizontal interconnectedness of the different aquifers, percolate down to replace the extracted deep groundwater. This will cause the down-percolating fresh groundwater to become salinized in the deep saline aquifers, which means that extracting the deep brackish and saline groundwater is not only an emptying process of the deep groundwater but also it is an emptying process of the fresh groundwater overlying them. The results allow to conclude that any extraction of the deep groundwater in areas lying to the north of Ras en Naqab Escarpment will have damaging impacts on the fresh groundwater in the overlying fresh groundwater aquifers. This article strongly advises not to extract the deep brackish and saline groundwater, but to conserve that groundwater as a base supporting the overlying fresh groundwater resources, and that will help in protecting the thermal mineralized water springs used in spas originating from these deep aquifers. The increasing water needs of the country can be covered by the desalination of seawater at Aqaba, which is the only viable option for Jordan at present and in the coming decades. 展开更多
关键词 groundwater Salinity Sources of Salinity Interconnectedness of Aquifers Absurdity of Deep groundwater Exploitation
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Hydrogeological and Physico-Chemical Study of the Groundwater of Mitendi South-East in the Commune of Mont-Ngafula around the Kimwenza Quarry (Province of Kinshasa, DR Congo)
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作者 Jonathan Mayi Nkolomonyi Ivon Ndala Tshiwisa +2 位作者 Hervé Khonde Mbumba Samuel Ingila Asanga Clement N’zau Umba-Di-Mbudi 《Journal of Geoscience and Environment Protection》 2024年第4期96-114,共19页
The exploitation of groundwater by drilling in the Mitendi South-East district constitutes a solution to the water shortage in this peripheral part of the Mont-Ngafula township in Kinshasa, the capital of the DR Congo... The exploitation of groundwater by drilling in the Mitendi South-East district constitutes a solution to the water shortage in this peripheral part of the Mont-Ngafula township in Kinshasa, the capital of the DR Congo. Individuals exploit groundwater in boreholes to serve the population without taking into account certain necessary aspects such as the origin of the groundwater table and the quality which constitute the major problems of this work such as: What is the quantity of water from the recharge of our aquifer? What is the state of the Mitendi South-East aquifer water in relation to some physico-chemical parameters? The cardinal objective of this work is to provide chemical data and trace elements in each analyzed borehole and determine the type of recharge of the underground aquifer. The specific objectives are as follows: analyze the potability of groundwater on a physico-chemical level and their chemical facies, take the geographical coordinates of water samples from the aquifer in each targeted borehole in order to develop the sampling map of the area under study;also check each parameter analyzed in relation to WHO standards. We carried out a general investigation of the study area by carrying out observations, sampling and in-situ measurements of each borehole, as well as the good conservation of the samples taken in a cooler. The various measurements that we took in-situ: pH, electrical conductivity, turbidity, salinity, temperature, and TDS were carried out by using a multi-parameter probe in the laboratory of appropriate methods such as titled-sorting, spectrophotometry, atomic absorption spectrometry, ArcGise and Excel software. With regard to the results from laboratory analysis (physical and chemical analysis), the parameters showed that the standards recommended by the WHO were not respected. We affirm that the water consumed in the Mitendi South-East district in Mont-Ngafula town ship is not drinkable. Since, it can cause several water-borne diseases. It would be better to treat that water before being drunk. . 展开更多
关键词 groundwater Aquifer Physicochemical Parameters Mitendi Kimwenza Quarry
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Groundwater recharge via precipitation in the Badain Jaran Desert,China
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作者 Zhe Wang Li-juan Wang +3 位作者 Jian-mei Shen Zhen-long Nie Le Cao Ling-qun Meng 《Journal of Groundwater Science and Engineering》 2024年第1期109-118,共10页
Precipitation infiltration serves as a significant source of groundwater in the Badain Jaran Desert.To investigate variations in precipitation infiltration within the desert,this study collected data on moisture conte... Precipitation infiltration serves as a significant source of groundwater in the Badain Jaran Desert.To investigate variations in precipitation infiltration within the desert,this study collected data on moisture content and temperature from the vadose zone through in-situ field monitoring.Utilizing these data,a numerical model is employed to explore the mechanism of groundwater recharge via precipitation.The results are as follows:(1)Moisture content and temperature in the shallow vadose zone exhibit significant seasonal variations,with moisture content diminishing with increasing depth;(2)Groundwater recharge via precipitation infiltration initially increases and then decreases with groundwater level depth(GWD).Peak groundwater recharge via precipitation occurs at a GWD of 0.75 m,decreasing to merely 0.012 cm at GWDs exceeding 2 m;(3)Groundwater is no longer susceptible to phreatic water evaporation when the GWD reaches approximately 3.7 m.Therefore,GWD plays a crucial role in governing groundwater recharge via precipitation in the Badain Jaran Desert. 展开更多
关键词 Badain Jaran Desert Vadose zone groundwater recharge In situ monitoring Numerical simulation
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Hydrochemical Characterisation and Assessment of the Level of Contamination of Groundwater Collected by Private Waterworks in the Town of Moundou in the South of Chad
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作者 Prosper Doumtoudjinodji Elegbede Manou Bernadin +3 位作者 Jean Claude Doumnang Mbaigane Nguérassem Djoueingue Urbain Agnichola Akilou Socohou Amadou 《Journal of Geoscience and Environment Protection》 2024年第1期13-32,共20页
Groundwater is the main source of drinking water for large cities in most African countries. In Moundou, for example, the conventional groundwater supply system is failing. To compensate for this state failure, the po... Groundwater is the main source of drinking water for large cities in most African countries. In Moundou, for example, the conventional groundwater supply system is failing. To compensate for this state failure, the population is building boreholes and wells, most of which tap the surface water table, generally referred to as the “water table”. The aim of this study is to characterize these waters in order to assess their level of contamination and, by extension, the degree of pollution of the water table. Major elements such as: Chloride (Cl<sup>-</sup>), Sulfate (SO<sub>4</sub><sup>2-</sup>), Nitrate (NO<sub>3</sub><sup>-</sup>), Calcium (Ca<sup>2+</sup>), magnesium (Mg<sup>2+</sup>), sodium (Na<sup>+</sup>) and potassium (K<sup>+</sup>) were analysed by Liquid Chromatography and the Bicarbonate ion (HCO<sub>3</sub><sup>-</sup>) was determined by the titrimetric method. The methodology applied is based on a combination of hydrochemical techniques and statistical analysis (PCA and CHA). A sampling campaign was carried out during high-water periods. The results of the physico-chemical analyses show mineralization ranging from 7.29 to 3670 μS/cm, with an average of 487.44 μS/cm. The groundwater studied is generally acidic, with a pH ranging from 3.26 to 6.41. Based on their anions, they are classified into four main hydrochemical facies: chloride and sulphate facies, calcium and magnesium facies, sodium and potassium facies and bicarbonate facies. The various correlations between major ions and statistical analyses have enabled us to identify three hydrogeochemical processes involved in water mineralization. The dominant process is silicate hydrolysis, followed by cation exchange, then anthropogenic input, which influences mineralization by polluting the water. 展开更多
关键词 Drinking Water groundwater Chemical Pollution Moundou Chad
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Pollution source identification methods and remediation technologies of groundwater: A review
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作者 Ya-ci Liu Yu-hong Fei +2 位作者 Ya-song Li Xi-lin Bao Peng-wei Zhang 《China Geology》 CAS CSCD 2024年第1期125-137,共13页
Groundwater is an important source of drinking water.Groundwater pollution severely endangers drinking water safety and sustainable social development.In the case of groundwater pollution,the top priority is to identi... Groundwater is an important source of drinking water.Groundwater pollution severely endangers drinking water safety and sustainable social development.In the case of groundwater pollution,the top priority is to identify pollution sources,and accurate information on pollution sources is the premise of efficient remediation.Then,an appropriate pollution remediation scheme should be developed according to information on pollution sources,site conditions,and economic costs.The methods for identifying pollution sources mainly include geophysical exploration,geochemistry,isotopic tracing,and numerical modeling.Among these identification methods,only the numerical modeling can recognize various information on pollution sources,while other methods can only identify a certain aspect of pollution sources.The remediation technologies of groundwater can be divided into in-situ and ex-situ remediation technologies according to the remediation location.The in-situ remediation technologies enjoy low costs and a wide remediation range,but their remediation performance is prone to be affected by environmental conditions and cause secondary pollution.The ex-situ remediation technologies boast high remediation efficiency,high processing capacity,and high treatment concentration but suffer high costs.Different methods for pollution source identification and remediation technologies are applicable to different conditions.To achieve the expected identification and remediation results,it is feasible to combine several methods and technologies according to the actual hydrogeological conditions of contaminated sites and the nature of pollutants.Additionally,detailed knowledge about the hydrogeological conditions and stratigraphic structure of the contaminated site is the basis of all work regardless of the adopted identification methods or remediation technologies. 展开更多
关键词 groundwater pollution Identification of pollution sources Geophysical exploration identification Geochemistry identification Isotopic tracing Numerical modeling Remediation technology Hydrogeological conditions Hydrogeological survey engineering
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Convergence Issues Associated with Cutoff Energies and Ab Initio Studies of Adsorption of CO on W and Pt
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作者 Sathya Hanagud Roussislava Zaharieva 《Journal of Materials Science and Chemical Engineering》 2024年第3期1-8,共8页
The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were ba... The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. . 展开更多
关键词 CO Adsorption Tungsten and Pt surfaces Cutoff Energy Selection convergence of Ab Initio Energy
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Almost Sure Convergence of Proximal Stochastic Accelerated Gradient Methods
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作者 Xin Xiang Haoming Xia 《Journal of Applied Mathematics and Physics》 2024年第4期1321-1336,共16页
Proximal gradient descent and its accelerated version are resultful methods for solving the sum of smooth and non-smooth problems. When the smooth function can be represented as a sum of multiple functions, the stocha... Proximal gradient descent and its accelerated version are resultful methods for solving the sum of smooth and non-smooth problems. When the smooth function can be represented as a sum of multiple functions, the stochastic proximal gradient method performs well. However, research on its accelerated version remains unclear. This paper proposes a proximal stochastic accelerated gradient (PSAG) method to address problems involving a combination of smooth and non-smooth components, where the smooth part corresponds to the average of multiple block sums. Simultaneously, most of convergence analyses hold in expectation. To this end, under some mind conditions, we present an almost sure convergence of unbiased gradient estimation in the non-smooth setting. Moreover, we establish that the minimum of the squared gradient mapping norm arbitrarily converges to zero with probability one. 展开更多
关键词 Proximal Stochastic Accelerated Method Almost Sure convergence Composite Optimization Non-Smooth Optimization Stochastic Optimization Accelerated Gradient Method
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Harmful evaluation of heavy metals from soil layer to the groundwater: Take the Jilin Hunchun Basin as an example
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作者 Xiao-Dong Guo Qiang Liu +3 位作者 Hui-Rong Zhang Xu-Fei Shi Chuan-Yu Qin Zhi-Qiang Zhang 《China Geology》 CAS CSCD 2024年第1期116-124,共9页
The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the ... The continuous enrichment of heavy metals in soils has caused potential harm to groundwater.Quantitative methods to evaluate the harm of heavy metals in soil to groundwater are lacked in previous studies.Based on the theory of groundwater circulation and solid-liquid equilibrium,a simple and easy-touse flux model of soil heavy metals migrating to groundwater is constructed.Based on groundwater environmental capacity,an innovative method for evaluating the harm of heavy metals in soil to groundwater is proposed,which has been applied in Hunchun Basin,Jilin Province,China.The results show that the fluxes of soil heavy metals into groundwater in the study area are Zn,Cu,As,Pb,Cd,Ni,and Hg in descending order.The content of heavy metals in groundwater(As,Hg,Cu,Pb,Zn,Ni,and Cd)in most areas has not risen to the threshold of environmental capacity within 10 years.The harm levels of soil heavy metals to groundwater in the most townships soils are at the moderate level or below.This evaluation method can quantify the flux of soil heavy metals into groundwater simply and quickly,determine the residual capacity of groundwater to heavy metals,evaluate the harm level of soil heavy metals to groundwater,provide support for relevant departments to carry out environmental protection of soil and groundwater,and provide a reference to carry out similar studies for related scholars. 展开更多
关键词 Soil heavy metals As+Hg+Cu+Pb+Zn+Ni+Cd Environmental capacity groundwater Hazard degree Migration flux model Agricultural geological survey engineering Hunchun Basin Jilin Province
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Influence of underground space development mode on the groundwater flow field in Xiong’an new area 被引量:3
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作者 Yi-hang Gao Jun-hui Shen +4 位作者 Lin Chen Xiao Li Shuang Jin Zhen Ma Qing-hua Meng 《Journal of Groundwater Science and Engineering》 2023年第1期68-80,共13页
The degree and scale of underground space development are growing with the continuous advancement of urbanization in China.The lack of research on the change of the groundwater flow field before and after the developm... The degree and scale of underground space development are growing with the continuous advancement of urbanization in China.The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation.This paper took the key development zone of the Xiong’an New Area as the study area,and used the Groundwater modeling system software(GMS)to analyse the influence on the groundwater flow field under the point,line,and surface development modes.The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer.The groundwater level on the upstream face of the underground structure would rise,while the water level on the downstream face would drop.The“line”concurrent development has the least impact on the groundwater flow field,and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m.The“surface”development has the greatest impact on the groundwater flow field,and the maximum rise of water level is expected to be 7.17 m. 展开更多
关键词 Xiong’an new area groundwater flow field Underground space GMS
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Determining safe yield and mapping water level zoning in groundwater resources of the Neishabour Plain 被引量:1
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作者 Parisa Kazerani Ali Naghi Ziaei Kamran Davari 《Journal of Groundwater Science and Engineering》 2023年第1期47-54,共8页
Groundwater is a crucial sources of water supply,especially in arid and semi-arid areas around the world.With uncontrolled withdrawals and limited availability of these resources,it is essential to determine the safe ... Groundwater is a crucial sources of water supply,especially in arid and semi-arid areas around the world.With uncontrolled withdrawals and limited availability of these resources,it is essential to determine the safe yield of these valuable resources.The Hill method approach was used in this study to determine the safe yield the Neishabour aquifer in Khorasan Razvi province in Iran.The results showed that the safe yield in the Neishabour aquifer is 60%lower than the current pumping amounts during the study period,indicating that further overdrafts could result in the destruction of this aquifer.This highlights the importance of using the Hill method to estimate the permitted exploitation from other aquifers,thus preventing problems caused by over-extraction and maintaining stability of global groundwater levels. 展开更多
关键词 Hill method Water level zoning maps groundwater pumping Safe yield groundwater crisis
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Determine the most appropriate strategy for groundwater management in arid and semi-arid regions, Abhar Plain, Iran 被引量:1
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作者 Fatemeh Einlo Mohammad Reza Ekhtesasi +1 位作者 Mehdi Ghorbani Parviz Abdinejad 《Journal of Groundwater Science and Engineering》 2023年第2期97-115,共19页
Due to growing demand and reduction of water resources and increasing pollution of water,driven by dramatic population and economic growth, arid and semi-arid land's imminent water problems are nowadays aggravatin... Due to growing demand and reduction of water resources and increasing pollution of water,driven by dramatic population and economic growth, arid and semi-arid land's imminent water problems are nowadays aggravating. This study aims to determine the most appropriate management strategies for balancing the Abhar plain aquifer using the SWOT coupled with AHP technique. The results indicate that weaknesses prevail over strengths as well as threats over opportunities. The placement in the quarter of weaknesses-threats with a defensive strategy indicates the critical condition of the Abhar plain aquifer. The most appropriate solutions to achieve the goal of balancing the groundwater were prioritized by AHP method. According to results, improper management of water consumption with a weight of 72.5% is the most destructive factor in reducing groundwater resources. Among the types of consumption, the effect of an agricultural factor carries a weight of 74.2%. The exploitation of illegal wells, overdraft of exploitation license provisions of wells, reduction of precipitation and traditional irrigation methods were selected as the destructive factors causing the deteriration of groundwater resources. Also, with filling the illegal wells,changing the type of cultivation and greenhouse crops cultivation, installing a smart water meter,observance the provisions of the water exploitation license, implementing integrated pressurized irrigation systems, benefiting from suitable climatic conditions and geographical location for cultivating and developing the low-water use species and industries and on the other hand, with implementing artificial recharge to control the surface water resources and reduce abstraction from groundwater aquifers, the adverse trend of Abhar Plain groundwater resources can be controlled. 展开更多
关键词 groundwater balancing Model SWOT AHP Abhar Plain aquifer
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