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Natural Hazards - The Urmia Lake basin is one of the most important basins in Iran, facing many problems due to poor water management and rainfall reduction. Under current circumstances, it becomes... 相似文献
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Developing an expert group method of data handling system for predicting the geometry of a stable channel with a gravel bed 总被引：2，自引：0，他引：2 
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下载免费PDF全文 Azadeh Gholami Hossein Bonakdari Isa Ebtehaj Saba Shaghaghi Fatemeh Khoshbin 《地球表面变化过程与地形》2017,42(10):1460-1471
Predicting the geometry of channels and alluvial rivers is of primary importance in river engineering science. Appropriately designing channels and predicting stable river cross‐sections can decrease costs and prevent the destruction of installations and agricultural land by rivers. Consequently, researchers have applied different empirical and regression methods to achieve relations for predicting stable channel and river geometry. In this study, Group Method of Data Handling ]GMDH) models are used to predict three geometric variables of stable channels, namely width (w), depth (h) and slope (s). The effect of different input parameters, such discharge (Q), median grain size (d50) and the Shields parameter (τ*) on the GMDH models is assessed with regard to predicting stable channel geometry. The results indicate that the GMDH model with mean absolute percentage error (MAPE) of 5.53%, 4.05% and 4.89% for channel width, depth and slope prediction respectively, exhibits good accuracy. Moreover, a comparison of the GMDH models with previous theoretical equations (based on regression analysis) indicates the superiority of GMDH model performance, with error reductions of one‐fifth, one‐eighth and one‐sixth compared with the regression equations for channel width, depth and slope prediction, respectively. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Water Resources - In this study groundwater potential map of Khorramabad in Lorestan Province, Iran was produced using two different methods; Frequency Ratio (FR) and Weights of Evidence (WoE)... 相似文献
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Keyvani Fatemeh Amani Mohammad J. Kalantariasl Azim Vahdani Hossein 《Natural Resources Research》2020,29(3):1857-1874
Natural Resources Research - Measurement and modeling of fluid properties and phase behavior of gas condensate reservoir fluids are challenging tasks. Many researchers proposed various empirical... 相似文献
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Fatemeh Sarjoughian Ali Kananian Michael Haschke Jamshid Ahmadian 《Geological Journal》2016,51(3):387-404
The South Dehgolan pluton, in NW Iran was emplaced into the Sanandaj–Sirjan magmatic–metamorphic zone. This composite intrusion comprises three main groups: (1) monzogabbro–monzodiorite rocks, (2) quartz monzonite–syenite rocks, and (3) a granite suite which crops out in most of the area. The granites generally show high SiO2 content from 72.1%–77.6 wt.% with diagnostic mineralogy consisting of biotite and amphibole along the boundaries of feldspar–quartz crystals which implies anhydrous primary magma compositions. The granite suite is metaluminous and distinguished by high FeOt/MgO ratios (av. 9.6 wt.%), typical of ferroan compositions with a pronounced A‐type affinity with high Na2O + K2O contents, high Ga/Al ratios, enrichment in Zr, Nb, REE, and depletion in Eu. The quartz monzonite–syenites show intermediate SiO2 levels (59.8%–64.5 wt.%) with metaluminous, magnesian to ferroan characteristics, intermediate Na2O + K2O contents, enrichment in Zr, Nb, REE, Ga/Al, and depletion in Eu. The monzogabbro–monzodiorites show overall lower SiO2 content (48.5%–55.9 wt.%) with metaluminous and calc‐alkaline compositions, relatively lower Na2O + K2O contents, low Ga/Al ratios, and FeOt/MgO (av. 1.6 wt.%) ratios, low abundances of Zr, Nb, and lower REE element concentrations relative to the granites and quartz monzonite–syenites. These geochemical differences among the three different rocks suites are likely to indicate different melt origins. We suggest that the South Dehgolan pluton resulted from a change in the geodynamic regime, from compression to extension in the Sanandaj–Sirjan zone during Mesozoic subduction of the Neo‐Tethys oceanic crust beneath the Central Iranian microcontinent. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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For the first time, the calcareous nannofossils of the chalky limestone of upper Abderaz Formation and lower part of Abtalkh Formation have been studied. In this study, 83 nannoplanktonic species of 45 genera were identified and presented. A biostratigraphic study of calcareous nannofossils from this section has allowed the recognition of five calcareous nannofossil biozones of Sissingh (Geol Mijnbouw 56:37–65, 1977) CC17–CC21. On the obtained calcareous nannofossils, the age of this section is Late Santonian/Early Campanian–Early Late Campanian. 相似文献
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As a generalization of the Brans-Dicke type scalar-tensor gravity in a braneworld context, we study cosmological phase space of a braneworld model with induced gravity in the presence of a scalar field on the brane. We consider a quintom field minimally or non-minimally coupled to induced gravity on the warped DGP brane and we present a detailed analysis of the critical points, their stability and late-time cosmological viability of the solutions within a phase space approach. In particular, de Sitter solutions, different from the famous self-accelerated branch of the DGP model are found and the phase-space analysis for checking their attractor properties is performed. We analyze also the possibility of crossing of the phantom divide by the effective equation of state parameter of the model. We also focus on the classical stability of the solutions in w–w′ phase plane. 相似文献
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We study quasinormal modes (QNMs) of uncharged Grumiller black hole (GBH). This massive BH has a Rindler acceleration a, and hence it is also called Rindler modified Schwarzschild BH. After reducing the radial equation of the massless Klein-Gordon equation to the Zerilli equation, we compute the complex frequencies of the QNMs of the GBH. To this end, an approximation method which considers small perturbations around its horizon is used. Considering the highly damped QNMs in the process proposed by Maggiore, the quantum entropy and area spectra of these BHs are found. Although the QNM frequencies are tuned by the Rindler term, we show in detail that the spacing does not depend on it. Here, the dimensionless constant ? of the area spectrum is found to be double of its Schwarzschild value. The latter result is also discussed. 相似文献
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J. Amnyattalab H. Rezaie 《International Journal of Environmental Science and Technology》2018,15(12):2625-2636
Stability of an earth dam is affected by different factors of which the most important is seepage. One of the factors in defining the seepage rate is hydraulic conductivity coefficients in suctions and various moistures in earth dam body in which different models of soil–water retention curves are used to be defined. In this study, first the soil–water retention curves of van Genuchten and Brooks–Corey models are used to predict the soil–water retention of different body layers of 2 dams. Then, hydraulic conductivity coefficients are calculated through Mualem and Burdine’s models. Water seepage rate and the stability of dams were calculated in two phases: I. construction finalization prior to intaking water and II. rapid drawdown of water. Bishop and Morgenstern–Price methods are used to analyze the stability of dams. The stability and seepage results demonstrate that simultaneous use of Brooks–Corey’s soil–water retention curve with Mualem’s method results in the highest seepage rate in comparison with van Genuchten’s model in case of variable n, m and Burdine hydraulic conductivity. Safety factors achieved from both cases of construction finalization prior to intaking water and rapid drawdown of water demonstrated the accuracy and reliability of hydraulic coefficient prediction. 相似文献
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