排序方式： 共有104条查询结果，搜索用时 15 毫秒
41.
The Mozduran Formation includes light-coloured, thick-bedded to massive limestone and porous dolomitic limestone and dolomite. In this study, 13 samples from the uppermost Mozduran Formation were taken from two localities and examined for calcareous nannofossils. A total of 19 species and 12 genera were identified in the Mozduran section and19 species and 13 genera for the Taherabad section. Based on these assemblages, the uppermost Mozduran Formation is assignable to Sissingh's (1977) biozone CC1 (Early Berriasian) at the Mozduran section and to biozone CC3 (Late Valanginian) at the Taherabad section. Thus, the formation is younger from east to west across the basin. 相似文献
42.
Mohammadanvar Moheghy Fatemeh Hadavi Lida Khodadadi Marziyeh Notghi Moghaddam 《Arabian Journal of Geosciences》2014,7(10):4203-4220
By attention to the stratigraphic value of calcareous nannoplanktons for the age determination of sedimentary beds, for the first time Late Cretaceous calcareous nannofossil taxa, their distributions and relative abundances were recorded from the lower and the upper boundary of Aitamir Formation located in northeast Iran. In the present study, biostratigraphy and paleoecological conditions were reconstructed. The Aitamir Formation comprises glauconitic sandstones and olive-green shales. In this work, samples were prepared with smear slides, and nannofossils of these boundaries are listed and figured. They were photographed under a light microscope. Based on nannoplanktons and as a result of biostratigraphic studies, the age of the lower boundary of the Aitamir Formation in the east Kopet Dagh is Early/Middle Turonian, the age of the lower boundary in the west Kopet Dagh is Late Turonian/Early Coniacian, the age of the upper boundary of the Aitamir Formation in the east Kopet Dagh is Late Santonian, and the age of the upper boundary of this Formation in the west Kopet Dagh is Early Campanian. Based on paleoecological interpretation, the Aitamir Formation was deposited in a shallow marine environment, at relatively low latitude. A deepening trend of the sedimentary basin is recognized passing from Aitamir Formation to the overlying Abderaz Formation while in the lower boundary from Sanganeh to Aitamir Formation depth decreased. 相似文献
43.
Davoud Agha‐Aligol Mohammad Lamehi‐Rachti Parvin Oliaiy Farah Shokouhi Mohammad Farmahini Farahani Mahmoud Moradi Fatemeh Farshi Jalali 《Geoarchaeology》2015,30(3):261-270
It had long been thought that obsidian found in Iranian sites originated from Anatolia and Armenia, but new research has challenged this assumption. In this study, 68 samples of obsidian obtained from an archaeological survey of Nader‐Tepe Aslanduz were analyzed by Proton Induced X‐ray Emission (PIXE). Nader‐Tepe Aslanduz is a tell site west of the city of Aslanduz in the Parsabad county of the Ardebil province in northern Iran. The site was inhabited from the first millennium B.C. to A.D. 17, and its history may extend back to the third or fourth millennium B.C. Our chemical composition results have been combined with obsidian composition data from Turkey and Armenia and subjected to Principal Component Analysis (PCA). This analysis shows that obsidian from each location can be grouped into distinctive classes—the obsidian from Nader‐Tepe Aslanduz is therefore probably derived from volcanic outcrops of the Sahand and Sabalan region. This study has been unable to assign a known source from Anatolia and Armenia for the obsidian of Nader‐Tepe Aslanduz. 相似文献
44.
ABSTRACTThe performance of eight empirical equations for estimating ETo at 80 weather stations in Iran is evaluated. The equations assessed are Hargreaves (HGS), Trajkovic (TKC), Berti (BTI), Ravazzani (RZI), Irmak (IMK), Turc (TRC) and two Valiantzas methods (VTS1 and VTS2). The FAO56 reference crop Penman-Monteith (PM) equation is used as a baseline to evaluate their performance. Also, a Köppen climate classification map for Iran is developed and the best ETo method for each climate type identified. The updated Köppen climate map shows six climate sub-classes; BWh, BWk, BSh, BSk, Csa and Dsa in Iran with a percentage of land area covered by each sub-class of 43, 17, 7, 9, 11 and 13%, respectively. The best performing ETo equation for each climate class in Iran was HGS for BSh, VTS1 for BWk, and VTS2 for BSk, BWh, Csa and Dsa. 相似文献
45.
46.
Fatemeh Sadeghi Mohammad Reza Mehrnia Ramin Nabizadeh Mohammad Hossein Sarrafzadeh 《洁净——土壤、空气、水》2012,40(4):416-421
The objective of this study was to investigate the effect of salt concentration on performance of a membrane bioreactor (MBR) for treating an olefin plant wastewater. For this purpose, a lab‐scale submerged MBR with a flat‐sheet ultrafiltration membrane was used for treatment of synthetic wastewater according to oxidation and neutralization unit of olefin plant. The synthetic wastewater was adjusted to have 500 mg/L chemical oxygen demand (COD). Trials on different concentrations of sodium sulfate (Na2SO4) (0–20 000 ppm) in the feed were conducted under aerobic conditions in the MBR. The results showed that increasing the salt concentrations causes an increase in the effluent COD, phenol, and oil concentrations. These results are due to reduction of the membrane filtration efficiency and also decline in the microbial activity that it is indicated by decreasing the sOUR in MBR. But in all the trials, the effluent COD and oil concentration was well within the local discharge limit of 100 and 10 mg/L, respectively. These results indicate that the MBR system is highly efficient for treating the olefin plant wastewater, and although high salt concentrations decreased organic contaminant removal rates in the MBR, the effluent still met the discharge limits for treating the olefin plant wastewater. 相似文献
47.
Khaled Zoroufchi Benis Esmaeil Fatehifar Sirous Shafiei Fatemeh Keivani Nahr Yaser Purfarhadi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(3):779-793
A new method is developed to design a multi-objective and multi-pollutant sensitive air quality monitoring network (AQMN) for an industrial district. A dispersion model is employed to estimate the ground level concentration of the air pollutants emitted from different emission sources. The primary objective of AQMN is providing the maximum information about the pollutant with respect to (1) maximum coverage area, (2) maximum detection of violations over ambient air standards and (3) sensitivity of monitoring stations to emission sources. Ant Colony Optimization algorithm (ACO) and Genetic Algorithm (GA) are adopted as the optimization tools to identify the optimal configuration of the monitoring network. The comparison between the results of ACO and GA shows that the performance of both algorithms is acceptable in finding the optimal configuration of AQMN. The application of the method to a network of existing refinery stacks indicates that three stations are suitable to cover the study area. The sensitivity of the three optimal station locations to emission sources is investigated and a database including the sensitivity of stations to each source is created. 相似文献
48.
Hossein Ebrahimian Fatemeh Jalayer Domenico Asprone Anna M. Lombardi Warner Marzocchi Andrea Prota Gaetano Manfredi 《地震工程与结构动力学》2014,43(14):2179-2197
Operative seismic aftershock risk forecasting can be particularly useful for rapid decision‐making in the presence of an ongoing sequence. In such a context, limit state first‐excursion probabilities (risk) for the forecasting interval (a day) can represent the potential for progressive state of damage in a structure. This work lays out a performance‐based framework for adaptive aftershock risk assessment in the immediate post‐mainshock environment. A time‐dependent structural performance variable is adopted in order to measure the cumulative damage in a structure. A set of event‐dependent fragility curves as a function of the first‐mode spectral acceleration for a prescribed limit state is calculated by employing back‐to‐back nonlinear dynamic analyses. An epidemic‐type aftershock sequence model is employed for estimating the spatio‐temporal evolution of aftershocks. The event‐dependent fragility curves for a given limit state are then integrated together with the probability distribution of aftershock spectral acceleration based on the epidemic‐type aftershock sequence aftershock hazard. The daily probability of limit state first‐excursion is finally calculated as a weighted combination of the sequence of limit state probabilities conditioned on the number of aftershocks. As a numerical example, daily aftershock risk is calculated for the L'Aquila 2009 aftershock sequence (central Italy). A representative three‐story reinforced concrete frame with infill panels, which has cyclic strength and stiffness degradation, is used in order to evaluate the progressive damage. It is observed that the proposed framework leads to a sound forecasting of limit state first‐excursion in the structure for two limit states of significant damage and near collapse. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
49.
National Persian Gulf Bridge is a communication route between Bandar Abbas port and Qeshm Island located on the southern border of Iran. This causeway has important role for facilitating the transportation system between Qeshm Island and mainland, i.e., Bandar Abbas. Based on geotechnical and geological site investigation records, the bridge is located on the deposits with high seismic possibility and subsequently significant dynamic loading. Therefore, adequate substructure design of this bridge as an offshore project is realized as a major requirement. The geophysical and geotechnical investigations have been done to obtain the subsoil characteristics of the project site. For this purpose, 18 boreholes have been performed to do in situ tests and extract samples for laboratory testings. Data synthesis indicates that in the zones close to Qeshm Island and in the deeper parts of the sea, the strata is made of clay with loose sands and some depths, with silty sands. Hence, instability issues, including the low bearing capacity and the high differential settlement, are significant aspects in analysis and design of substructure for this project. Also, in this paper, the subsoil conditions have been studied from in situ tests such as standard penetration test (SPT) and cone penetration test (CPT) results in order to achieve an appropriate foundation system. Moreover, the necessity of the ground improvement of the site has been investigated to propose an efficient technique for safe and secure construction. Based on the analysis and methods screened, the vibro-replacement method is considered as a suitable and efficient ground improvement method for this project. 相似文献
50.