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71.
Mirmohammad Miri Ali asghar Sepahi Farhad Aliani Mohammad Maanijou 《Arabian Journal of Geosciences》2016,9(13):619
Amphibolite layers of the Hamedan area (Sanandaj-Sirjan zone, west Iran) contain amphibole crystals with strong optical zoning. These amphibolites occur as interlayers in middle Jurassic, Buchan-type andalusite-garnet-staurolite and sillimanite-garnet-andalusite schist of the area that were intruded by late Jurassic magmatic bodies of the Alvand plutonic complex. Electron microprobe analyses results show that the zoned amphiboles have ferrohornblende cores that change to ferroedenite toward the rims. The core-to rim increase of Al, Fe, Na, and K and decrease of Si and Mg along with edenitic substitution in amphiboles is consistent with increase in metamorphic grade. Thermobarometry calculations based on amphibole composition and hornblende-plagioclase thermometry provided 492 to 508 o C and 4.3 to 4.9 kbar for the inner cores, 495 to 514 o C and 4.5 to 5.1 kbar for the outer cores, 538 to 564 o C and 5.3 to 5.8 kbar for the inner rims and 552 to 573 o C and 5.5 to 5.9 kbar for the outer rims, respectively. These results point to a nearly isobaric prograde P-T path for the Hamedan area amphibolites, compatible with a metamorphic evolution dominated by the thermal perturbation associated with the late Jurassic magmatism of the northern Sanandaj-Sirjan zone. 相似文献
72.
Development of Rock Engineering Systems-Based Models for Flyrock Risk Analysis and Prediction of Flyrock Distance in Surface Blasting 总被引：2，自引：1，他引：1
Farhad Faramarzi Hamid Mansouri Mohammad Ali Ebrahimi Farsangi 《Rock Mechanics and Rock Engineering》2014,47(4):1291-1306
The environmental effects of blasting must be controlled in order to comply with regulatory limits. Because of safety concerns and risk of damage to infrastructures, equipment, and property, and also having a good fragmentation, flyrock control is crucial in blasting operations. If measures to decrease flyrock are taken, then the flyrock distance would be limited, and, in return, the risk of damage can be reduced or eliminated. This paper deals with modeling the level of risk associated with flyrock and, also, flyrock distance prediction based on the rock engineering systems (RES) methodology. In the proposed models, 13 effective parameters on flyrock due to blasting are considered as inputs, and the flyrock distance and associated level of risks as outputs. In selecting input data, the simplicity of measuring input data was taken into account as well. The data for 47 blasts, carried out at the Sungun copper mine, western Iran, were used to predict the level of risk and flyrock distance corresponding to each blast. The obtained results showed that, for the 47 blasts carried out at the Sungun copper mine, the level of estimated risks are mostly in accordance with the measured flyrock distances. Furthermore, a comparison was made between the results of the flyrock distance predictive RES-based model, the multivariate regression analysis model (MVRM), and, also, the dimensional analysis model. For the RES-based model, R 2 and root mean square error (RMSE) are equal to 0.86 and 10.01, respectively, whereas for the MVRM and dimensional analysis, R 2 and RMSE are equal to (0.84 and 12.20) and (0.76 and 13.75), respectively. These achievements confirm the better performance of the RES-based model over the other proposed models. 相似文献
73.
Ali Akbar Shahsavari Kamal Khodaei Rahele Hatefi Farhad Asadian Seyed Mohammad Zamanzadeh 《Arabian Journal of Geosciences》2014,7(6):2367-2375
Determination of total petroleum hydrocarbon distribution (TPH) in groundwater of Dezful aquifer was the main purpose of this study. The study area, which is located between latitudes 32°00′ and 32°35′?N and longitudes 48°10′ and 49°35′?E, covers about 1,920 km2 in the north of Khuzestan Province, Iran. Hydrocarbon pollutants in the area were being released into the aquifer, from a variety of sources. An oil pipe crash accident, which occurred on 19 Feb. 2009 in the vicinity of the northern part of the study area, released about 6,000 barrels of crude oil to the Karkhe River. Other possible sources of TPH in the region are asphalt factories, gas stations, and the Sabzab oil pump station. Since the main source of drinking water in the Dezful area is groundwater reservoirs, this study would be very crucial, especially when there is considerable agricultural activity in the area as well. In order to determine the presence of TPH and heavy metals in the groundwater, samples were taken from wells with different usage within two periods, i.e., in Nov. 2008 and May 2009. The second sampling operation was carried out to determine the effect of the accident in the water resources. In situ groundwater parameter measurements including pH, dissolved oxygen, temperature, and electrical conductivity were also carried out in the field. Based on the results, there are four zones in the study area which were contaminated with TPH from different origins: (1) southeast of Dezful City, which was contaminated by Shokati gas station; (2) southeast of Shush City, which was contaminated by an asphalt factory; (3) southwest of Dezful City, which was contaminated by Sabzab oil pump station; and (4) the shores of Karkhe River which were contaminated due to the pipeline crash accident. This could be a serious threat to the environment and human health because TPH concentration was higher than the EPA standard in the study area. Heavy metals were not distributed in a uniform pattern in the aquifer. The concentrations were lower than the contamination level based on the EPA drinking standard, and there was no meaningful relation between concentrations of TPH and the heavy metals. It was recommended that a monitoring network should be designed to monitor oil contaminants in the ground and surface water monthly because of importance of the water resources and presence of potential oil contaminant sources. 相似文献
74.
A new remedy is proposed in this study to increase the ductility of cross-braced frames to a level comparable with ductile moment frames. The suggested system consists of one or two concentric steel rings installed in the cross-braced bay vertically. The steel rings are designed such that they fail in bending sooner than failure of the braces in compression.Then the rings act as seismic fuses with multiple bending plastic hinges. Using nonlinear static analysis, it is shown that the proposed sys... 相似文献