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1.
Interactive effect of nitrogen fertilizer and hydrocarbon pollution on soil biological indicators 总被引：2，自引：1，他引：1
Somayeh Emami Ahmad Ali Pourbabaei Hossein Ali Alikhani 《Environmental Earth Sciences》2014,72(9):3513-3519
The investigation of the impact of different forms of nitrogen fertilizer (NO3-N and NH4-N) on microbial parameters, enzyme activities and phytotoxicity in a petroleum-contaminated soil was evaluated by an incubation study. The tested enzymes, microbial activity and seed germination index showed different patterns in response to both petroleum and nitrogen fertilizer addition and time of incubation. The results apparently showed that the contamination of soil with petroleum has a negative effect on soil ecosystem. Nitrogen fertilizer could improve inhibition of petroleum hydrocarbons in soil. Nevertheless, nitrogen fertilizer had no significant effect on urease activity in the petroleum-contaminated soil. As compared to NO3-N, the addition of NH4-N to the soil resulted in a greater impact on soil performance as attested by the recovery of the soil germination capability and higher values of the respiration. The application of nitrogen fertilizer may be suggested as a good strategy for restoring soils in regions affected by the same problem. 相似文献
2.
In this research, the spatial and temporal distribution of Mesoscale Convective Systems was assessed in the southwest of Iran using Global merged satellite IR brightness temperature (acquired from Meteosat, GOES, and GMS geostationary satellites) and synoptic station data. Event days were selected using a set of storm reports and precipitation criteria. The following criteria are used to determine the days with occurrence of convective systems: (1) at least one station reported 6-h precipitation exceeding 10 mm and (2) at least three stations reported phenomena related to convection (thunderstorm, lightning, and shower). MCSs were detected based on brightness temperature, maximum areal extent, and duration thresholds (228 K, 10,000 km2, and 3 h, respectively). An MCS occurrence classification system is developed based on mean sea level, 850 and 500 hPa pressure patterns.
The results indicated that the highest frequency of MCSs occurred in December and April. Assessment of MCSs spatial frequency showed that MCS occurrence is strongly correlated with topography in April and May unlike the cold months. In other words, the role of Zagros Mountains in developing MCSs varies based on the season so that its impact increases with enhancement of mean monthly temperature. In addition, the occurrence of MCSs depends closely on the configuration of the Sudan Low in the southwest of Iran.
相似文献3.
M.R. Sheikholeslami A. Pique P. Mobayen M. Sabzehei H. Bellon M. Hashem Emami 《Journal of Asian Earth Sciences》2008,31(4-6):504-521
The Neyriz region includes outcrops of metamorphic rocks that are thrust over the Neotethyan ophiolites. These rocks are affected by a major deformational event, the result of which includes a shearing polyphase foliation present in gneissic core domes, overprinted by a crenulation cleavage. These fundamental structures developed contemporaneously with a medium-pressure metamorphism which is characterized by the syn-kinematic crystallization of kyanite and the beginning of anatexis, followed by the development of retrometamorphic mineral parageneses. The major deformation phase in the area occurred during the Early-Cimmerian orogeny in the Late Triassic. Following the orogeny, the gneiss domes started to rise into the upper levels of the crust. From the geodynamic point of view, after the Mid-Permian the studied area was situated at southern passive margin of the Iranian plate; the central Iranian microcontinent at that time was separated by the Neotethys ocean from the Gondwanian supercontinent. After the Late Triassic the region became an active margin associated with an accretionary prism. The margin was finally involved in an orogenic wedge after the closure of the Neotethyan oceanic basin in the Late Mesozoic. Closure of the basin resulted in a major thrusting of the metamorphic rocks of the southern Iranian margin over the Neotethyan ophiolites. 相似文献
4.
M. Maleki S. Ebrahimi F. Asadzadeh M. Emami Tabrizi 《International Journal of Environmental Science and Technology》2016,13(3):937-944
Wind erosion is a serious problem throughout the world which results in soil and environment degradation and air pollution. The main objective of this study was to evaluate feasibility of microbial-induced carbonate precipitation, as a novel soil-strengthening technique, to reduce wind erosion risk of a sandy soil. For this purpose, the erosion of biocemented soil samples was investigated experimentally in a wind tunnel under the condition of wind velocity of 45 km h?1. The weight loss of treated samples relative to the weight loss of control treatment was 1.29 and 0.16 % for low and high bacterial mix concentrations, respectively, indicating a significant improvement in erosion control in biologically treated samples. The effect of biological treatment on wind erosion control was even superior at the higher velocities. Thereafter, the penetration resistance of the surface layers as a simple index of resistance against wind erosion was measured. Significant improvements in the penetration resistance of the treated soil samples were observed. Although low bacterial mix concentrations did not significantly improve the penetration resistance of the samples, significant improvements in the penetration resistance of the treated soil samples were observed reaching to the highest measured strength (56 kPa) in high bacterial mix concentrations samples. Finally, the morphology of precipitated CaCO3 crystals using scanning electron microscopy and X-ray powder diffraction analysis showed that the CaCO3 was mainly precipitated as vaterite crystals forming point-to-point contacts between the sand granules. 相似文献
5.
Naghizade Asl Fateme Asgari Hamid Reza Emami Hojat Jafari Mohammad 《Geotechnical and Geological Engineering》2021,39(5):3347-3360
Geotechnical and Geological Engineering - Mulching is fastest strategy to control sand dune movement in arid and semiarid areas. In the present study the effect of micro silica- cement mixture was... 相似文献
6.
Application of the WEPP model to determine sources of run‐off and sediment in a forested watershed 
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下载免费PDF全文 This study investigates critical run‐off and sediment production sources in a forested Kasilian watershed located in northern Iran. The Water Erosion Prediction Project (WEPP) watershed model was set up to simulate the run‐off and sediment yields. WEPP was calibrated and validated against measured rainfall–run‐off–sediment data. Results showed that simulated run‐off and sediment yields of the watershed were in agreement with the measured data for the calibration and validation periods. While low and medium values of run‐off and sediment yields were adequately simulated by the WEPP model, high run‐off and sediment yield values were underestimated. Performance of the model was evaluated as very good and satisfactory during the calibration and validation stages, respectively. Total soil erosion and sediment load of the study watershed during the study period were determined to be 10 108 t yr?1 and 8735 t yr?1, respectively. The northern areas of the watershed with dry farming were identified as the critical erosion prone zones. To prioritize the subwatersheds based on their contribution to the run‐off and sediment production at the watershed's main outlet, unit response approach (URA) was applied. In this regard, subwatersheds close to the main outlet were found to have the highest contribution to sediment yield of the whole watershed. Results indicated that depending on the objective of land and water conservation practices, particularly, for controlling sediment yield at the main outlet, critical areas for implementing the best management practices may be identified through conjunctive application of WEPP and URA. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
Hossein?Kouhestani Majid?GhaderiEmail author Khin?Zaw Sebastien?Meffre Mohammad?Hashem?Emami 《Mineralium Deposita》2012,47(4):425-440
The breccia-hosted epithermal gold–silver deposit of Chah Zard is located within a high-K, calc-alkaline andesitic to rhyolitic
volcanic complex in the central part of the Urumieh-Dokhtar Magmatic Arc (UDMA), west central Iran. The total measured resource
for Chah Zard is ∼2.5 million tonnes of ore at 12.7 g/t Ag and 1.7 g/t Au (28.6 t Ag, 3.8 t Au), making it one of the largest
epithermal gold deposits in Iran. Magmatic and hydrothermal activity was associated with local extensional tectonics in a
strike-slip regime formed in transtensional structures of the Dehshir-Baft strike-slip fault system. The host rocks of the
volcanic complex consist of Eocene sedimentary and volcanic rocks covered by Miocene sedimentary rocks. LA-ICP–MS U–Pb zircon
geochronology yields a mean age of 6.2 ± 0.2 Ma for magmatic activity at Chah Zard. This age represents the maximum age of
mineralization and may indicate a previously unrecognized mineralization event in the UDMA. Breccias and veins formed during
and after the waning stages of explosive brecciation events due to shallow emplacement of rhyolite porphyry. Detailed systematic
mapping leads to the recognition of three distinct breccia bodies: volcaniclastic breccia with a dominantly clastic matrix;
gray polymict breccia with a greater proportion of hydrothermal cement; and mixed monomict to polymict breccia with clay matrix.
The polymictic breccias generated bulk-mineable ore, whereas the volcaniclastic breccia is relatively impermeable and largely
barren. Precious metals occur with sulfide and sulfosalt minerals as disseminations, as well as in the veins and breccia cements.
There is a progression from pyrite-dominated (stage 1) to pyrite-base metal sulfide and sulfosalt-dominated (stages 2 and
3) to base metal sulfide-dominated (stage 4) breccias and veins. Hydrothermal alteration and deposition of gangue minerals
progressed from illite-quartz to quartz-adularia, carbonate, and finally gypsum-dominated assemblages. Free gold occurs in
stages 2 and 4, principally intergrown with pyrite, quartz, chalcopyrite, galena, sphalerite, and Ag-rich tennantite–tetrahedrite,
and also as inclusions in pyrite. High Rb/Sr ratios in ore-grade zones are closely related to sericite and adularia alteration.
Positive correlations of Au and Ag with Cu, As, Pb, Zn, Sb, and Cd in epithermal veins and breccias suggest that all these
elements are related to the same mineralization event. 相似文献
8.
Modeling and Interpretation of Pressuremeter Test Results with Artificial Neural Networks 总被引：1，自引：1，他引：0
In this paper, three types of artificial neural network (ANN) are employed to prediction and interpretation of pressuremeter test results. First, multi layer perceptron neural network is used. Then, neuro-fuzzy network is employed and finally radial basis function is applied. All applied networks have shown favorable performance. Finally, different models have been compared and network with the most outstanding performance in two stages is determined. Contrary to conventional behavioral models, models based neural network do not demonstrate the effect of input parameters on output parameters. This research is response to this need through conducting sensitivity analysis on the optimal structure of proposed models. 相似文献
9.
Su Rongxiang Dodge Somayeh Goulias Konstadinos G. 《Journal of Geographical Systems》2022,24(3):353-388
Journal of Geographical Systems - Movement is manifested through a series of patterns at multiple spatial and temporal scales. Movement data today are becoming available at increasingly... 相似文献
10.
This study investigated the effect of cations and anions on the sorption and desorption of iron (Fe) and manganese (Mn) in six surface calcareous soil samples from Western Iran. Six 10 mM electrolyte background solutions were used in the study, i.e., KCl, KNO3, KH2PO4, Ca(NO3)2, NaNO3, and NH4NO3. NH4NO3 and NaNO3 increased the soil retention of Fe and Mn, whereas Ca(NO3)2 decreased the soil retention of Fe and Mn. Iron and Mn sorption was decreased by NO3 ? compared with H2PO4 ? or Cl?. The Freundlich equation adequately described Fe and Mn adsorption, with all background electrolytes. The Freundlich distribution coefficient (K F) decreased in the order H2PO4 ? > Cl? > NO3 ? for Mn and H2PO4 ? > NO3 ? > Cl? for Fe. The highest sorption reversibility was for Fe and Mn in competition with a Ca2+ background, indicating the high mobility of these two cations. A MINTEQ speciation solubility model showed that Fe and Mn speciation was considerably affected by the electrolyte background used. Saturation indices indicated that all ion background solutions were saturated with respect to siderite and vivianite at low and high Fe concentrations. All ion background solutions were saturated with respect to MnCO3(am), MnHPO4, and rhodochrosite at low and high Mn concentrations. The hysteresis indices (HI) obtained for the different ion backgrounds were regressed on soil properties indicating that silt, clay, sand, and electrical conductivity (EC) were the most important soil properties influencing Fe adsorption, while cation exchange capacity (CEC), organic matter (OM), and Mn-DTPA affected Mn adsorption in these soils. 相似文献