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341.
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
342.
Kaolin, cordierite, and calcite are investigated as supports for TiO2. The prepared TiO2/support samples are examined for the removal of organic dyes from wastewater. The samples are preliminarily investigated to identify the optimal loaded system using synthetic wastewater containing methylene blue (MB). Data indicate that the investigated support significantly affects the photocatalytic activity of the supported TiO2. Low photocatalytic activity toward MB degradation is observed upon using TiO2/calcite when compared to the unsupported TiO2. Interaction between calcite and titania species probably occurrs to produce the less photoactive CaTiO3 amorphous species. Anatase TiO2 is obtained upon using kaolin and cordierite as supports. The low photocatalytic performance of the TiO2/kaolin sample is also observed. A high concentration of MB on TiO2/kaolin surfaces blocks the photoactive sites. TiO2/cordierite shows the highest photocatalytic activity compared to the unsupported TiO2 as well as the other TiO2/support samples. Rigid cordierite particles suppress the agglomeration of TiO2 particles during the preparation, leading to a high exposed surface of TiO2 towards light illumination. TiO2/cordierite is investigated for the removal of organic dye from real wastewater collected from a textile dyeing factory. Color removal of up to 46% is achieved upon UV irradiation. 相似文献
343.
Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs 下载免费PDF全文
Klemens Katterbauer Santiago Arango Shuyu Sun Ibrahim Hoteit 《Geophysical Prospecting》2017,65(1):337-364
Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels and estimating critical reservoir parameters, the sparse spatial nature of this dataset limits the efficiency of the history matching process. Recently, gravimetry techniques have significantly advanced to the point of providing measurement accuracy in the microgal range and consequently can be used for the tracking of gas displacement caused by water influx. While gravity measurements provide information on subsurface density changes, i.e., the composition of the reservoir, these data do only yield marginal information about temporal displacements of oil and inflowing water. We propose to complement gravimetric data with interferometric synthetic aperture radar surface deformation data to exploit the strong pressure deformation relationship for enhancing fluid flow direction forecasts. We have developed an ensemble Kalman‐filter‐based history matching framework for gas, gas condensate, and volatile oil reservoirs, which synergizes time‐lapse gravity and interferometric synthetic aperture radar data for improved reservoir management and reservoir forecasts. Based on a dual state–parameter estimation algorithm separating the estimation of static reservoir parameters from the dynamic reservoir parameters, our numerical experiments demonstrate that history matching gravity measurements allow monitoring the density changes caused by oil–gas phase transition and water influx to determine the saturation levels, whereas the interferometric synthetic aperture radar measurements help to improve the forecasts of hydrocarbon production and water displacement directions. The reservoir estimates resulting from the dual filtering scheme are on average 20%–40% better than those from the joint estimation scheme, but require about a 30% increase in computational cost. 相似文献
344.
Oreochromis niloticus is an endemic species in the River Nile and represents the main object of fishery in the Nile Delta Lakes of which Lake Maryût is the smallest and most polluted. Due to current pollution problems, fish production in the lake greatly declined. Besides fish biology, this study considered a wide array of water databases in selected sites along the lake. Hydrologic and biologic data were compared to that of a reference fish hatchery. Water concentrations of ammonia, manganese, nickel, cadmium, lead and mercury proved hazardous to fish, whereas chromium, copper, iron, zinc, pH, alkalinity, hardness, phosphate, nitrate, and nitrite always fell within acceptable levels. Physiologic evaluation of O. niloticus pointed out improper growth, protein inadequacy, and functional impairment in fish inhabiting polluted sites, in particular the lake main basin. These were reflected by data of specific formulae as RNA/DNA and the relative RNA content (r) in cells of the liver and gill arches as well as by the relative mobilization of serum protein fractions. It seems, however, that growth competence is additionally affected by the stress impact exerted upon fish by massive population numbers in some cramped commercial ponds. 相似文献