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901.
Balamurugan Palani Sivaprakasam Vasudevan Thirunavukkarasu Ramkumar 《Arabian Journal of Geosciences》2017,10(20):449
The present study investigates the anthropogenic metal input into the lake system, the toxic metal pollution in the sediments of Kodaikanal Lake. Surface sediment samples were collected at seven locations to represent its spatial variability within the lake. Samples were subjected to analyze for Fe, Co, Cr, Mn, Ni, Zn, Cd, Cu, Ag, Pb, Hg, and As by energy dispersive X-ray fluorescence (EDXRF) and their concentrations in lake sediments range from 102,000–109,000, 561–2699, 292–544, 211–482, 79–163, 57–265, 57–74, 37–92, 46–59, 20–97, 19–30, to 13–24 mg/kg, respectively. The sources of pollution were inferred through spatial and statistical analyses. Most of the toxic metal contents in the sediments are found to exceed the background concentration in all locations. The enrichment factor (EF) and index of geoaccumulation (I geo) of Hg, Co, Cd, and Ag showed that sediments of Kodaikanal Lake exhibit the probability of anthropogenic influence. The significant Pearson’s correlation coefficient is also suggesting that they probably originated from the same source of occurrence. The contamination factor and degree of contamination of the Kodaikanal Lake sediments are strongly polluted in terms of most of the examined metals. The study also provides environmentally significant information about anthropogenic influence on the lake sediments. 相似文献
902.
The Wadi Badaa (WB) Upper Miocene clays, Cairo-Suez district, Egypt, represent materials for the ceramic production. The clay raw materials are composed mainly of smectite and kaolinite with minor quartz, calcite, and rare feldspar. The plasticity indices vary between 24 and 30%, suggesting that these clays are plastic raw materials. IR bands of the investigated clays were observed at 3695, 3619, 1032, 916, 794, 690, 534, 466, and 423 cm?1 for kaolinite; at 3436, 1635, 916, and 466 cm?1 for smectite; and at 1179, 1104, 794, 690, and 466 cm?1 for quartz. The <2 μm particle sizes of samples are relatively abundant in clays (~33%), which is adequate for uses of the ceramic products because of containing fine particle sizes. The studied WB clays contain 7.95 and 12.35% moisture water and interlayer water, respectively, with a maximum drying shrinkage of 7.87% at room temperature; therefore, the WB clays could be used in the ceramic manufacture. 相似文献
903.
904.
Integrated biostratigraphic studies are undertaken on the newly discovered Gondwana successions of Purnea Basin which have been recognized in the subsurface below the Neogene Siwalik sediments. The four exploratory wells, so far drilled in Purnea Basin, indicated the presence of thick Gondwana sussession (± 2450m) with varied lithological features. However, precise age of different Gondwanic lithounits of this basin and their correlation with standard Gondwana lithounits is poorly understood due to inadequate biostratigraphic data.Present biostratigraphic studies on the Gondwana successions in the exploratory wells of PRN-A, RSG-A, LHL-A and KRD-A enable recognition of fifteen Gondwanic palynological zones ranging in age from Early Permian (Asselian-Sakmarian) to Late Triassic (Carnian-Norian). Precise age for the Gondwanic palynological zones, recognized in the Purnea Basin and already established in other Indian Gondwana basins, are provided in the milieu of additional palynological data obtained from the Gondwana successions of this basin.The Lower Gondwana (Permian) palynofloras of Purnea Basin recorded from the Karandighi, Salmari, Katihar and Dinajpur formations resemble the palynological assemblages earlier recorded from the Talchir, Karharbari, Barakar and Raniganj formations respectively, and suggests the full development of lower Gondwana succession in this basin. The Upper Gondwana (Triassic) succession of this basin is marked by the Early and Middle to Late Triassic palynofloras that resemble Panchet and Supra-Panchet (Dubrajpur/Maleri Formation) palynological assemblages, and indicates the occurrence of complete Upper Gondwana succession also in the Purnea Basin.The lithological and biostratigraphic attributes of Gondwana sediments from Purnea, Rajmahal and western parts of Bengal Basin (Galsi Basin) are almost similar and provides strong evidences about the existence of a distinct N-S trending Gondwana Graben, referred as the Purnea-Rajmahal-Galsi Gondwana Graben. Newly acquired biostratigraphic data from the Gondwana sediments of CHK-A, MNG-A and PLS-A wells from central part of Bengal Basin and Bouguer anomaly data suggest that these wells fall in a separate NE-SW trending graben of “Chandkuri-Palasi-Bogra Gondwana Graben”. Although, the post-Gondwana latest Jurassic-Early Cretaceous Rajmahal Traps and and intertrappean beds succeed the Upper Gondwana successions in Rajmahal, Galsi and Chandkuri-Palasi Gondwana basins, but not recorded in the drilled wells of Purnea Basin, instead succeeded by the Neogene Siwalik sediments. 相似文献
905.
Noratiqah Mohd Ariff Abdul Aziz Jemain Mohd Aftar Abu Bakar 《Environmental Earth Sciences》2017,76(17):625
Selecting suitable distributions for rainfall data is usually subjective and complex since it requires decision-makers to consider results from various measures of goodness-of-fit indices. In this study, the VIKOR method in multi-criteria decision-making analysis is modified to select the most suitable plotting positions to represent extreme storm intensities in order to build the intensity–duration–frequency (IDF) curves of storm events. This is done by considering the rankings provided by all goodness-of-fit indices used to obtain a compromise solution. Nine plotting positions are considered: Weibull (W), Adamowski (A), Gringorten (G), Hazen (H) and Gumbel (EV I) and two known plotting positions for generalized extreme value (GEV) distribution using Pearson’s skewness and another two using L-skewness. The IDF curves obtained are compared to a reference IDF curves which was found using the GEV distribution. The mean and median for three goodness-of-fit indices, the coefficient of variation of root mean square error, CVRMSE, the mean percentage of difference, Δ, and the coefficient of determination, R 2, are taken as the criteria for selection process. The results show that six plotting positions, A, H, W, G and the two plotting positions with L-skewness, are equally superior compared to the other three plotting positions. 相似文献
906.
Concerns over the rapid retreat rates of mountain glaciers have been rising as global temperatures have continued to increase. The extent of variation in the retreat of mountain glaciers can provide information about changes to different climatic conditions. Assessing the retreat rates of glaciers is crucial to assess the continuing existence of mountain glaciers and the ramifications of those retreats on water security for human societies. Therefore, mathematical and statistical models for the quantification of glacier dynamics in response to climate change are in high demand. In this research, we propose a multivariate regression model that estimates glacier change and predicts the location of glacier terminus over time, based on observed climate factors. The proposed method is applied to temporal sequences of ground observations for a number of glaciers around the globe. This model can potentially be used for monitoring glacier systems using climatic factors. 相似文献
907.
Xiaojuan YU 《Geotechnical and Geological Engineering》2017,35(1):293-301
The ecological concept has become more widespread and biotechnical slope protection has been accepted by more people as environmental policies become more stringent. Biotechnical slope protection has become widely used because of its unique features, which include wave resistance, waterproof flow-scour protection, greening and landscaping effects, environmental friendliness, and positive social benefits. Slope surfaces are exposed to and affected by natural conditions, particularly storm-water scouring, which has an obvious impact on slope instability. However, most previous studies have focused on soil reinforcement by plant root systems in non-saturated soil conditions, and soil reinforcement in saturated soil conditions after rainfall has rarely been studied. In this study, we conducted laboratory-based storm-water scouring experiments to assess the erosional effect of storm-water scouring on slopes, reveal the mode and process of failure of natural and vegetated slopes under storm-water scouring, and develop and refine the mechanism and theoretical understanding of soil reinforcement by plants. 相似文献
908.
Michael E. Hohn 《Mathematical Geosciences》2017,49(8):1077-1079
909.
Imposing any tax among carbon tax, sulfur tax and nitrogen tax on fossil fuels will also reduce the other two air pollutants. Neglecting the synergistic effect of each energy environmental tax and levying carbon tax, sulfur tax and nitrogen tax at the same time will overestimate the abatement cost of air emissions. This study adopts a partial equilibrium model which uses linear demand and supply curves to illustrate the emission reductions in carbon tax, sulfur tax and nitrogen tax. The synergistic reduction effects of CO2, SO2 and NO x are firstly evaluated under the implicit tax scenario of resource tax and consumption tax on fossil fuels. Then it is compared with the synergistic reduction effects of CO2, SO2 and NO x under different explicit tax scenarios of increasing tax rate on carbon tax, sulfur tax and nitrogen tax. If the synergistic reduction effect of explicit environmental taxes is better, this research aims to find one kind of environmental tax among carbon tax, sulfur tax and nitrogen tax with the best synergistic reduction effect and to provide a decision support for the policy makers of energy environmental taxes. The results indicate that explicit environmental taxes have better synergistic reduction effects compared with the current implicit environmental taxes. And explicit sulfur tax can lead to the largest synergistic reduction effects of CO2, SO2 and NO x . Therefore, the policy makers of energy environmental taxes could consider adopting the explicit sulfur tax to reduce various environmental air emissions at the largest amount. 相似文献
910.
Estimating the undiscovered mineral resources of a terrane is a challenging, yet essential, task in mineral exploration. We
apply Zipf’s law rank statistical analysis to estimate the undiscovered nickel sulphide resources in the Norseman-Wiluna Greenstone
Belt, Western Australia. The analysis suggests that about 3.0 to 10.0 Mt of nickel sulphide resources are yet to be discovered
in this belt, compared to the currently known total nickel sulphide endowment of 10.8 Mt. This undiscovered nickel sulphide
endowment is likely to be hosted by incompletely delineated deposits and undiscovered deposits in less explored komatiites
in the belt. Using the more detailed data subset of the Kambalda domain, this study manipulates Zipf’s law to estimate the
sizes of undiscovered deposits, in addition to the domain’s total nickel sulphide endowment estimate. Importantly, regression
analysis shows that the gradient of the line of best fit through the logarithmic rank-size plot for the detailed Kambalda
data subset is −1. This gradient, which is the key Zipf’s law constant k, has the value of −0.92 for the Norseman-Wiluna Greenstone Belt which is collectively less mature than the Kambalda domain.
This result corroborates the use of k = −1 in Zipf’s law predictive analyses of mineral resources for deposit populations for which the value of k = −1 has not yet been attained due to exploration immaturity. 相似文献