Pinpointing the key parameters in estimating the bed-load sediment flux in reservoir engineering     

Saeed Khorram  Mustafa Ergil 《Environmental Earth Sciences》2012,66(7):2109-2127

When a dam is constructed on a river to store water, sediments transported by the water flow are also stored and reservoir capacity is gradually reduced by sediment accumulation. Prediction of sediment distribution in reservoirs is an important issue for dam designers to determine the reservoir active storage capacity, outlet sill elevation, dam stability, recreational facilities, and backwater conditions. The main objective of this study is to develop the most reliable parameters of sedimentation that are directly or indirectly influencing in the equations and measured dataset. For validation of the proposed parameters, data of 40 reservoir sets gathered from different reliable sources, rather than focusing entirely on bed-load equations. Artificial neural network (ANNs) method was used to validate this study. Several graphs and statistical analysis were presented to emphasize the influencing effect of those parameters that were detected by ANNs and are directly controlling the error in the bed-load sediment flux using measured particles datasets.  相似文献   

Optimally locating additional drill holes in three dimensions using grade and simulated annealing   总被引：2，自引：0，他引：2  

Saeed Soltani Mohammadi  Ardeshir Hezarkhani  A. Erhan Tercan 《Journal of the Geological Society of India》2012,80(5):700-706

Average kriging variance is a standard tool used in optimization of the location of additional drill holes. However, this tool cannot distinguish between areas with different priorities. This limitation could be eliminated by using weighted average kriging variance. This paper extends the problem of optimal location to three dimensional cases, use grade as a weight and search optimum locations by simulated annealing. Weighted average kriging variance is used as objective function. The method is applied to a copper deposit. Results have shown that weighting of the estimation variance with ??grade?? is effective only when the difference among the grades estimated for different blocks is considerable.  相似文献   

Elemental characterization of black shales of Khyber Pakthunkhawa (KPK) region of Pakistan using AAS   总被引：1，自引：0，他引：1  

Abdul Aziz  Muhammad Sajjad  Bashir Mohammad 《中国地球化学学报》2013,32(3):248-251

Black shale samples were collected from Chimiari Khyber Pakthunkhawa region of Pakistan and were analyzed for elemental compositions. Atomic Absorption Spectrophotometry (AAS) was utilized for the determination of elements in the digested solutions. The analysis of black shale was performed precisely with relative standard deviation (RSD) lower than 2%. Results showed that the samples contained high concentrations of Ca (11.98 %), Al (7.09%), Fe (3.03%), Mg (0.59%) and Ti (0.58%).  相似文献   

Monte Carlo analysis of the effect of spatial distribution of storms on prioritization of flood source areas   总被引：1，自引：0，他引：1  

Bahram Saghafian  Saeed Golian  Mohammad Elmi  Ruhangiz Akhtari 《Natural Hazards》2013,66(2):1059-1071

Implementation of structural and non-structural flood control measures in flood-prone watersheds is on increasing demand. Different watershed areas are not necessarily hydrologically similar and impose variable effects on the outlet flow hydrograph. Meanwhile, prioritization of watershed areas in terms of flood generation is essential for economic flood control planning. Previous works have focused on the definition of a flood index that quantifies the contribution of each subwatershed unit or grid cell to the outlet flood hydrograph through the application of unit flood response (UFR) approach. In the present research, for the first time, the effect of spatial pattern of storm events on the flood index variation was assessed via a Monte Carlo uncertainty analysis. To do so, the UFR approach was carried out for a large number of randomly generated rainfall spatial pattern. The proposed methodology was adopted to the Tangrah watershed in northern Iran. The watershed is frequently hit by floods that have historically caused loss of life and properties. The results indicated that for the more frequent flood events, the flood index is quite sensitive to the spatial distribution of rainfall such that for the highest ranked subwatershed (SW6), the standardized variation of the flood index values (i.e., the uncertainty range) decreases from 1.0 to 0.5 when the rainfall depth increases from 20 to 150 mm, respectively. The results further revealed that increasing the rainfall depth from 20 to 150 mm would cause the effect of rainfall spatial distribution on subwatersheds’ flood indices to diminish. The implications are that if flood control measures are designed for more frequent floods with lower return periods, an uncertainty analysis is required to identify the range of flood index variations.  相似文献   

Evaluating the accuracy and uncertainty of atmospheric and wave model hindcasts during severe events using model ensembles     

Abdolali  Ali  van der Westhuysen  Andre  Ma  Zaizhong  Mehra  Avichal  Roland  Aron  Moghimi  Saeed 《Ocean Dynamics》2021,71(2):217-235

Ocean Dynamics - Various uncertainties exist in a hindcast due to the inabilities of numerical models to resolve all the complicated atmosphere-sea interactions, and the lack of certain ground...  相似文献   

Dynamic response of double beam rested on stochastic foundation under harmonic moving load     

Saeed Mohammadzadeh  Morteza Esmaeili  Mohammad Mehrali 《国际地质力学数值与分析法杂志》2014,38(6):572-592

This paper deals with the dynamic response of infinite double Euler–Bernoulli beam supported by elastic foundation with stochastic stiffness subjected to an oscillating moving load, which is the first research in relevant literature review. In this matter, equations of motion for double beam are formulated in a moving frame of reference. Moreover, by employing the first order perturbation theory and calculating contour integration, the response of double beam is obtained analytically and validated by a stochastic finite element model. Sensitivity analyses on the various parameters of closed form solution such as velocity, load frequency, coefficient of variation of soil foundation and rail and slab bending stiffness show the significant effect of load frequency on the dynamic response of the doubled beam. From practical point of view, the obtained results of the present study can be utilized efficiently in analysis and design of slab track systems. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Evaluating the effect of ocean-atmospheric indices on drought in Iran     

Mohammadrezaei  Maryam  Soltani  Saeed  Modarres  Reza 《Theoretical and Applied Climatology》2020,140(1):219-230

Theoretical and Applied Climatology - This study investigated the relationship between ocean-atmospheric indices and drought in Iran. Using > 30-year precipitation data from 37...  相似文献   

Counterfactual reasoning in space and time: Integrating graphical causal models in computational movement analysis     

Saeed Rahimi  Antoni B. Moore  Peter A. Whigham  Peter Dillingham 《Transactions in GIS》2023,27(7):1846-1864

Movement analysis is distinguished by an emphasis on understanding via observation and association. However, an important component of movement from the human and computer modeling perspective is the processes that bring about movement behavior in the first place. This article contextualizes the graphical causal modeling framework (for association, intervention, and counterfactual causal analysis) in GIScience, and more specifically within movement analysis studies. This is done by modeling the movement behavior of football players, applied to spatiotemporal data generated by an agent-based simulation. The movement dataset is thoroughly analyzed to infer the statistical associations among its variables, to estimate the effect of an intervention on some of those variables, and to answer a few counterfactual questions from the observations. We conclude that causal graphs (i.e., directed acyclic graphs), if implemented correctly, can assist analysts in infering causal relations from movement data. This research suggests the integration of causal graphs and agent-based paradigms as one solution for computational movement analysis.  相似文献   

White spot syndrome virus inactivation study by using gamma irradiation     

Marzieh Heidareh  Farahnaz Motamedi Sedeh  Mehdi Soltani  Saeed Rajabifar  Mohammad Afsharnasab  Aghil Dashtiannasab 《中国海洋湖沼学报》2014,32(5):1024-1028

The present study was conducted to investigate the effect of gamma irradiation on white spot syndrome virus(WSSV). White spot syndrome virus is a pathogen of major economic importance in cultured penaeid shrimp industries. White spot disease can cause mortalities reaching 100% within 3–10 days of gross signs appearing. During the period of culture, immunostimulant agents and vaccines may provide potential methods to protect shrimps from opportunistic and pathogenic microrganisms. In this study, firstly, WSSV was isolated from infected shrimp and then multiplied in crayfish. WSSV was purified from the infected crayfish haemolymph by sucrose gradient and confirmed by transmission electron microscopy. In vivo virus titration was performed in shrimp, Penaeus semisulcatus. The LD50 of live virus stock was calculated 10 5.4 /mL. Shrimp post-larvae(1–2 g) were treated with gamma-irradiated(different doses) WSSV(10 0 to 10-4 dilutions) for a period of 10 days. The dose/survival curve for irradiated and un-irradiated WSSV was drawn; the optimum dose range for inactivation of WSSV and unaltered antigenicity was obtained 14–15 kGy. This preliminary information suggests that shrimp appear to benefit from treatment with gammairradiated WSSV especially at 14–15 KGy.  相似文献   

Age and composition of Antarctic bedrock reflected by detrital zircons, erratics, and recycled microfossils in the Prydz Bay–Wilkes Land–Ross Sea–Marie Byrd Land sector (70°–240°E)     

J.J. Veevers  A. Saeed 《Gondwana Research》2011,20(4):710-738

The age and composition of the 14 × 10⁶ km² of Antarctica's surface obscured by ice is unknown except for some dates on detrital minerals. In remedy, we bring together proxies of Antarctic bedrock in the form of (1) detrital zircons analysed for U–Pb age, T_DM^C, εHf, and rock type, including five new analyses of Neogene turbidites, (2) erratics that reflect age, composition, and metamorphism, and (3) recycled microfossils that reflect age, facies, and metamorphism. Each sample is located in its ice-drainage basin for backtracking to the potential provenance. Gaps in age between sample and upslope exposure are specifically attributable to the provenance. This work indicates that the central Antarctic provenance about a core of the Gamburtsev Subglacial Mountains (GSM) and Vostok Subglacial Highlands (VSH) contains a basement that includes igneous (mafic granitoids) and metamorphic rocks with peak U–Pb ages of 0.5–0.7, 0.9–1.3, 1.4–1.7, 1.9–2.1, 2.2–2.3, 2.6–2.8, and 3.15–3.35 Ga, T_DM^C 1.3–3.6 Ga, and εHf + 12 to − 40. Other modelled cratons with similar ages are set in a matrix of foldbelts of 0.5–0.7 Ga age. The basement in the core is surmounted by Permian red beds, at the periphery by Permian and Triassic sedimentary rocks unaffected by igneous heating or load metamorphism, and west of the Transantarctic Mountains (TAM) in the Wilkes Basin arguably by Late Cretaceous through Pliocene marine sediments. Erratics of undated red sandstone along the coast of Wilkes Land and George V Land indicate a red-bed provenance in the interior. The Prince Charles Mountains (PCM) provide an exposed example of a crust of Precambrian igneous and metamorphic rocks and Permian and Triassic sedimentary rocks.  相似文献