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排序方式: 共有400条查询结果,搜索用时 15 毫秒
391.
A. T. M. Sakiur Rahman Chowdhury Sarwar Jahan Quamrul Hasan Mazumder Md. Kamruzzaman Takahiro Hosono 《Journal of the Geological Society of India》2017,89(1):47-56
The study analyzes drought using Standardized Precipitation Index (SPI) and Mann-Kendall (MK) Trend Test in the context of the impacts of drought on groundwater table (GWT) during the period 1971-2011 in the Barind area, Bangladesh. The area experienced twelve moderate to extreme agricultural droughts in the years 1972, 1975, 1979, 1982, 1986, 1989, 1992, 1994, 2003, 2005, 2009 and 2010. Some of them coincide with El Niño events. Hydrological drought also occurred almost in the same years. However, relationship between all drought events and El Niño is not clear. Southern and central parts of the area frequently suffer from hydrological drought, northern part is affected by agricultural drought. Trends in SPI values indicate that the area has an insignificant trend towards drought, and numbers of mild and moderate drought are increasing. GWT depth shows strong correlation with rainy season SPI values such that GWT regaining corresponds with rising SPI values and vice versa. However, 2000 onwards, GWT depth is continuously increasing even with positive SPI values. This is due to over-exploitation of groundwater and changes in cropping patterns. Agricultural practice in Barind area based on groundwater irrigation is vulnerable to drought. Hence, adaptation measures to minimize effects of drought on groundwater ought to be taken. 相似文献
392.
R D Kaplay T Vijay Kumar Soumyajit Mukherjee P R Wesanekar Md Babar Sumeet Chavan 《Journal of Earth System Science》2017,126(5):71
We study the margin of South East Deccan Volcanic Province around Kinwat lineament, Maharashtra, India, which is NW extension of the Kaddam Fault. Structural field studies document \(\sim \)E–W strike-slip mostly brittle faults from the basement granite. We designate this as ‘Western boundary East Dharwar Craton Strike-slip Zone’ (WBEDCSZ). At local level, the deformation regime from Kinwat, Kaddam Fault, micro-seismically active Nanded and seismically active Killari corroborate with the nearby lineaments. Morphometric analyses suggest that the region is moderately tectonically active. The region of intense strike-slip deformation lies between seismically active fault along Tapi in NW and Bhadrachalam in the SE part of the Kaddam Fault/lineament. The WBEDCSZ with the surface evidences of faulting, presence of a major lineaments and intersection of faults could be a zone of intraplate earthquake. 相似文献
393.
Jawad S. Alagha Mohammed Seyam Md Azlin Md Said Yunes Mogheir 《Hydrogeology Journal》2017,25(8):2347-2361
Artificial intelligence (AI) techniques have increasingly become efficient alternative modeling tools in the water resources field, particularly when the modeled process is influenced by complex and interrelated variables. In this study, two AI techniques—artificial neural networks (ANNs) and support vector machine (SVM)—were employed to achieve deeper understanding of the salinization process (represented by chloride concentration) in complex coastal aquifers influenced by various salinity sources. Both models were trained using 11 years of groundwater quality data from 22 municipal wells in Khan Younis Governorate, Gaza, Palestine. Both techniques showed satisfactory prediction performance, where the mean absolute percentage error (MAPE) and correlation coefficient (R) for the test data set were, respectively, about 4.5 and 99.8% for the ANNs model, and 4.6 and 99.7% for SVM model. The performances of the developed models were further noticeably improved through preprocessing the wells data set using a k-means clustering method, then conducting AI techniques separately for each cluster. The developed models with clustered data were associated with higher performance, easiness and simplicity. They can be employed as an analytical tool to investigate the influence of input variables on coastal aquifer salinity, which is of great importance for understanding salinization processes, leading to more effective water-resources-related planning and decision making. 相似文献
394.
S. Perveen T. Yigitcanlar Md. Kamruzzaman J. Hayes 《International Journal of Environmental Science and Technology》2017,14(3):663-678
Urban growth is an important phenomenon, which is taking place on an unprecedented scale, and its impacts on society and the environment are evident. In theory, an evaluation of such urban growth through scenario-based planning helps planners to better assess the future impacts of growth and develop better policies and plans. Within this context, the assessment of transport impacts is particularly important as transport plays an important role in shaping urban growth. Additionally, transport sector alone is responsible for about one-third of the greenhouse gas emissions of cities, which has detrimental effects on the environment, economy, community health, and quality of life. In practice, however, scarce evidence exists outlining the challenges of scenario-based evaluation and how to best address these while modelling the transport impacts of various urban growth scenarios. This research addresses these gaps in the literature and assesses the effectiveness of scenario-based planning methods that are used for modelling the transport impacts of alternative urban growth scenarios. The methodological approach of the study consists of a critical review of the key literature and relevant methods that are commonly used to assess transport impacts. The results of this analysis highlight limitations of existing methods for effectively evaluating transport externalities of urban growth scenarios. The findings suggest that among many reviewed models, the ILUTE, URBANSIM and TRANUS simulation models are identified as significant ones. However, due to various limitations of the former two, TRANUS is noted as the most suitable one for evaluating the transport impacts of urban growth scenarios. 相似文献
395.
Yassaman Babaee Catherine N. Mulligan Md. Saifur Rahaman 《Environmental Earth Sciences》2017,76(19):650
Due to the severity of arsenic contamination of soil and water resources around the world, finding new adsorbents for arsenic removal from the water is of high importance. The present study investigates the possible use and effectiveness of starch-stabilized Fe/Cu nanoparticles for adsorption of arsenic from aqueous solutions. First, Fe/Cu nanoparticles at various starch concentrations of 0, 0.02, 0.04 and 0.06 wt% were synthesized and characterized by X-ray diffraction, transmission electron microscopy and zeta potential/particle size analyzer. Then 0.04 wt% stabilized Fe/Cu nanoparticles were tested for the sorption of As(III) and As(V) from synthetic arsenic-contaminated water. To have an understanding about the arsenic adsorption mechanism of nanoparticles, X-ray photoelectron spectroscopy (XPS) was performed before and after adsorption. The results showed that starch provides nanoparticles with a neutral surface and stabilization of nanoparticles is possible with 0.04 wt% or higher concentrations of starch. For 0.04 wt% starch-stabilized Fe/Cu nanoparticles, the adsorption isotherms fit well within the Langmuir equation, with maximum sorption capacities of 90.1 mg/g for As(III) and 126.58 mg/g for As(V) at a pH of 7.0 from the aqueous arsenic solutions. Examining the XPS spectra of nanoparticles before and after adsorption showed that arsenic adsorption by this nanoparticle can be due to the formation of inner-sphere arsenic complexes on the particle surface, and the surface oxygen-containing functional groups involved in adsorption. The high sorption capacity suggests the potential for applying starch-stabilized Fe/Cu nanoparticles to the contaminated waters for removal of arsenic. 相似文献
396.
397.
Alhani Israa Jamal Noor Mohd Jamaludin bin Md Al-Bared Mohammed Ali Mohammed Harahap Indra Sati Hamonangan Albadri Wael Mahmood 《Acta Geotechnica》2020,15(11):3075-3093
Acta Geotechnica - During the construction of pavements, gravelly soil is used as the main material in the base and sub-base layers. Predicting the deformation behaviour of gravelly soil has been... 相似文献
398.
Hydro-geochemical evaluation of groundwater with studies on water quality index and suitability for drinking in Sagardari,Jashore 下载免费PDF全文
Ahmed Mohammad Tofayal Monir Minhaj Uddin Hasan Md Yeasir Rahman Md Mominur Rifat Md Shamiul Islam Islam Md Naim Khan Abu Shamim Rahman Md Mizanur Islam Md Shajidul 《地下水科学与工程》2020,8(3):259-273
Sagardari union is facing groundwater crisis because of contaminations from agriculture and urban sewage, which bring a considerable change in water quality. In view of this, hydro-chemical analyses were undertaken on 35 groundwater samples and the following hydro-geochemical parameters, pH, total dissolved solids (TDS), total hardness (TH), electrical conductivity (EC), cations and anions, were analyzed. From the analytical results, it is found that pH value was lower than WHO drinking water standard and the middle-downstream portions of the investigation region show higher EC. The piper plot indicates that the groundwater in Sagardari falls in the categories of NaClHCO3 hydro-chemical facies. Higher TH in groundwater was detected, but still in an acceptable range. In addition, salinity and arsenic ratio are higher and moderately higher, respectively. The spatial distribution of Groundwater Quality Index (GWQI) was determined by geo-statistical modelling of Sagardari union. The study provides information and supports the administration which to make better groundwater utilization and quality control in the Sagardari union. 相似文献
399.
Md.Sazzadur Rahman Ismail Hossain Pradip Kumar Biswas Md.Abdur Rahim A.S.M.Mehedi Hasan Md.Ibrahim Adham 《Acta Geochimica》2019,(3):404-413
The present study deals with the geochemistry of Late Quaternary ironstones in the subsurface in Rajshahi and Bogra districts, Bangladesh with the lithological study of the boreholes sediments. Major lithofacies of the studied boreholes are clay, silty clay, sandy clay, fine to coarse grained sand, gravels and sands with(fragmentary) ironstones. The ironstones contain major oxides, Fe_2 O_3*(*total Fe)(avg. 66.6 wt%), SiO_2(avg. 15.3 wt%), Al_2 O_3(avg. 4.0 wt%), MnO(avg. 7.7 wt%), and CaO(avg. 3.4 wt%). These geochemical data imply that the higher percentage of Fe_2 O_3* along with Al_2 O_3 and MnO indicate the ironstone as goethite and siderite, which is also validated by XRD data. A comparatively higher percentage of SiO_2 indicates the presence of relative amounts of clastic quartz and manganese-rich silicate or clay in these rocks. These ironstones also have significant amounts of MnO(avg. 7.7 wt%) suggesting their depositional environments under oxygenated condition. Chemical data of these ironstones suggest that the source rock suffered deep chemical weathering and iron was mostly carried in association with the clay fraction and organic matter. Iron concretion was mostly formed by bacterial build up in swamps and marshes, and was subsequently embedded in clayey mud.Within the coastal environments, the water table fluctuates and goethite and siderite with mud and quartz became dry and compacted to form ironstone. 相似文献
400.