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81.
The metapelitic schists of the Golpayegan region can be divided into four groups based on their mineral assemblages: (1) garnet-chloritoid schists, (2) garnet schists, (3) garnet-staurolite schists, and (4) staurolite-kyanite schists. Paleozoic pelagic shales experienced progressive metamorphism and polymetamorphism from greenschist to amphibolite facies along the kyanite geotherm. Mylonitic granites are concentrated in the central part of the region more than in other areas, and formed during the dynamic metamorphic phase by activity on the NW-SE striking Varzaneh and Sfajerd faults. The presence of chloritoid in the metapelites demonstrates low-grade metamorphism in the greenschist facies. The textural and chemical zoning of garnets shows three stages of growth and syntectonic formation. With ongoing metamorphism, staurolite appeared, and the rocks reached amphibolite facies, but the degree of metamorphism did not increase past the kyanite zone. Thus, metamorphism of the pelitic sediments occurred at greenschist to lower amphibolite facies. Thermodynamic studies of these rocks indicate that the metapelites in the north Golpayegan region formed at 511?C618°C and 0.24?C4.1 kbar. 相似文献
82.
While finding the optimal route for users with physical disabilities and personalizing routes for each user, on the one hand, and collaborative wayfinding, on the other hand, have been addressed in the pedestrian navigation systems literature, there has not been much research on combining the two activities. The problem associated with wayfinding approaches solely based on information about network segments and personal preferences is that the information about segments in the database may not, correctly and/or adequately address user preferences. The problem associated with wayfinding approaches solely based on the ratings given to routes by wheelchair users is the lack of rates (or scores) for all possible routes between all possible origin‐destination pairs in the network. This article discusses an approach to combine these two approaches for wayfinding to augment each other's shortcomings. To evaluate the personalized wayfinding approach, we utilize a route index, called a comparison index. The results show that with a P‐value of 9%, the routes obtained from our approach are more accessible than the routes obtained from another approach developed in another study. To evaluate the collaborative wayfinding approach, a Monte Carlo simulation was conducted which reflects the updates in routes as users' feedbacks become available. 相似文献
83.
The metamorphic rocks of the Aligudarz-Khonsar region can be divided into nine groups: slate, phyllite, sericite schist, biotite-muscovite schist, garnet schist, garnet-staurolite schist, staurolite schist, mylonitic granite, and marble. In this metamorphic region, four phases of metamorphism can be identified (dynamothermal, thermal, dynamic and retrograde metamorphism) and there are three deformation phases (D1, D2 and D3). Paleozoic pelagic shales experienced prograde metamorphism and polymetamorphism from the greenschist to amphibolite facies along the kyanite geotherm. The metapelites show prograde dynamothermal metamorphism from the greenschist to amphibolite facies. Maximum degree of dynamothermal metamorphism is seen in the Nughan bridge area. Also development of the mylonitic granites in the Nughan bridge area shows that dynamic metamorphism in this area was more intense than in other parts of the AligudarzKhonsar metapelitic zone. The chemical zoning of garnets shows three stages of growth and syn-tectonic formation. With ongoing metamorphism, staurolite appeared, and the rocks reached amphibolite facies, but the degree of metamorphism did not increase past the kyanite zone. Thus, metamorphism of the pelitic sediments occurred at the greenschist to amphibolite facies (kyanite zone). Thermodynamic studies of these rocks indicate that the metapelites in the Aligudarz-Khonsar region formed at 490–550°C and 0.47–5.6 kbar. 相似文献
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85.
Spatial prediction of soil erosion susceptibility: an evaluation of the maximum entropy model 总被引：1，自引：0，他引：1
Maryam Pournader Hasan Ahmadi Sadat Feiznia Haji Karimi Hamid Reza Peirovan 《Earth Science Informatics》2018,11(3):389-401
Soil erosion is considered as the most widespread form of soil degradation which causes serious environmental problems. This study investigates the performance of the maximum entropy (ME) in mapping rill erosion susceptibility in the Golgol watershed, Ilam province, Iran. To this end, ten rill erosion conditioning factors were selected to be employed in the modelling process based on an investigation of the literature. These layers are: elevation, slope percent, aspect, stream power index, topographic wetness index, distance from streams, plan curvature, lithology, land use, and soil. Then, a training dataset of rill erosion locations was used for modelling this phenomenon. The area under receiver operating characteristics curve was used for evaluating the performance of the ME model. In addition, Modified Pacific South-West Inter Agency Committee (MPSIAC) framework was applied and sediment yield was determined for different hydrological units in the study area. At last, Jackknife test was implemented to show the contribution of the factors in the modelling process. The results depicted that area under ROC curve for training and validation datasets were 0.867, and 0.794, respectively. Therefore, this conclusion can be achieved that ME worked well and could be a good tool for generating rill erosion susceptibility maps and its output could be employed for soil conservation in similar areas. 相似文献
86.
P. Tahmasebi M. H. Mahmudy-Gharaie F. Ghassemzadeh A. Karimi Karouyeh 《Environmental Earth Sciences》2018,77(22):766
The Kouh-e Zar mining area with iron oxide-rich types of Cu–Au (IOCG)-type gold mineralization is located in a fractured zone between two main “Darouneh” and “Taknar” faults in 35 km northwest of Torbat-e Heydarieh. In this study, the hydrogeochemistry and water quality of groundwater were examined for irrigation uses. Totally, 11 groundwater samples were collected in semi-arid area surrounding the mine. According to the irrigation water quality indices such as sodium absorption ratio, sodium percentage, residual sodium carbonate, residual sodium bicarbonate, potential salinity, salinity index, salinity hazard, permeability index and magnesium hazard, the water resources were appraised suitable to unsuitable. Na+ was a dominant cation and HCO3? was a dominant anion in the water samples. Fortunately, SO42? content is low (<?250 mg/L) in the water samples because of low-sulfide content mineralization in this mine. Water–rock interaction was defined as the controlling process on groundwater chemistry based on the Gibbs diagram. Calculated saturation indices revealed that the anion and cations in groundwater originated from dissolution of minerals and evaporation process. In the case of dominant Ca2+ and Mg2+, they were originated by dissolution of carbonate minerals such as calcite, dolomite and aragonite. Na+ was likely originated by plagioclase weathering in the brecciated volcanic rocks. Though the sulfidic mineralization is not so high in the Kouh-e Zar area, however, considering the existence of metalogenic mineralization in the Kouh-e Zar area, there is also a risk potential of release of toxic elements into the groundwater on which further deep investigation is ongoing in the area. 相似文献
87.
HassanA.Karimi 《测绘通报》2001,(6):44-45
分布式移动地理信息系统（DM-GIS）已成为GIS、GPS、无线通讯和移动计算技术集成的产物。野外工作队和移动车辆可用DM-GIS进行运算来确定最佳方案。DM-GIS的应用领域包括紧急任务、公用事业、运输、营救工作、电信、科学研究、环境监测和规划。本文介绍此系统的构成以及所面临的各种挑战。 相似文献
88.
Ali Seiphoori S. Mohsen Haeri Masoud Karimi 《Soil Dynamics and Earthquake Engineering》2011,31(5-6):792-804
In this study, the nonlinear seismic analysis of a typical three-dimensional concrete faced rockfill dam is reported. Three components of the Loma Prieta (Gilroy 1 station) earthquake acceleration time history are used as input excitation. The dam under study is considered as if it were located in a prismatic canyon with a trapezoidal cross-section. A nonlinear model for the rockfill material is used, and contact elements with Coulomb friction law are utilized at the slab–rockfill interface. Vertical joints in the face slab are also considered in the finite element model. A substructure method, in which the unbounded soil is modelled by the scaled boundary finite element method (SBFEM), is used to obtain the scattered motion and interaction forces along the canyon. The dam is subjected to spatially variable P, SV, and SH waves, and the effect of dam–foundation interaction and the reservoir water effects are considered. The results are compared with the non-scattered input motion analysis. Results of the analyses indicate that due to applying the scattered motion to the canyon the response of the dam and concrete face slab significantly increases. The reservoir water pressure affects the tensile stresses induced in the face slab by reducing the uplift movement of the concrete panels.Large horizontal axial forces are induced in the face slab due to out-of-phase and out-of-plane motions of the abutments. Although the normal movements of vertical joints are reduced due to the reservoir water confinement, the opening movements are still significant, and the local failure of construction joints is inevitable. 相似文献
89.
Dust storms are yet quite frequent in various parts of the world, particularly ancient Mesopotamia (approximately corresponding to most parts of Iraq as well as certain surrounding regions toward its north). To add to the ongoing difficulty, monitoring dust patterns has been proven to be a rather difficult endeavor given the absence of reliable ground-based monitoring stations in the corresponding area. Additionally, western provinces of Iran, especially Khuzestan in the southwest of Iran, have been severely affected by dust storms carried by the westerly winds, blown through neighboring countries in ancient Mesopotamia. This study proceeds to employ aerosol optical depth (AOD), extracted from the MODerate-resolution Imaging Spectroradiometer onboard the Terra spacecraft, to assess spatial dust variations between 2001 and 2017 over the Khuzestan province and ancient Mesopotamia. The variations were also correlated with the temporal dust changes in the Khuzestan province. Frequency of occurrence for AOD?>?1 was used to identify and categorize major dust sources in the aforementioned regions. The findings were indicative of an increasing trend in the annual AODs of the Khuzestan province, which eventually led to a significant increase from 2008 toward the end of 2012, but decreased again in the following years. Correspondingly, the entire time period (2001–2017) was further divided into three sub-periods: the first time period spanning from 2001 to 2007, followed by the second from 2008 to 2012 and finally a third time period from 2013 to 2017. Dust source identification was speculative of numerous dust spots in Iraq, Syria, Kuwait and also the southern parts of Khuzestan province which have become more active in recent years. Additionally, a large active dust spot was pinpointed between the northwest Iraq and eastern Syria border which has become extremely active during the second time period, possibly due to a severe drought in the Fertile Crescent.
相似文献90.
Different performance levels may be obtained for sideway collapse evaluation of steel moment frames depending on the evaluation procedure used to handle uncertainties. In this article, the process of representing modelling uncertainties, record to record (RTR) variations and cognitive uncertainties for moment resisting steel frames of various heights is discussed in detail. RTR uncertainty is used by incremental dynamic analysis (IDA), modelling uncertainties are considered through backbone curves and hysteresis loops of component, and cognitive uncertainty is presented in three levels of material quality. IDA is used to evaluate RTR uncertainty based on strong ground motion records selected by the k-means algorithm, which is favoured over Monte Carlo selection due to its time saving appeal. Analytical equations of the Response Surface Method are obtained through IDA results by the Cuckoo algorithm, which predicts the mean and standard deviation of the collapse fragility curve. The Takagi-Sugeno-Kang model is used to represent material quality based on the response surface coefficients. Finally, collapse fragility curves with the various sources of uncertainties mentioned are derived through a large number of material quality values and meta variables inferred by the Takagi-Sugeno-Kang fuzzy model based on response surface method coefficients. It is concluded that a better risk management strategy in countries where material quality control is weak, is to account for cognitive uncertainties in fragility curves and the mean annual frequency. 相似文献