نشریه زمین شناسی محیط زیست
پیاپی 23 (تابستان 1392)

Population increase, changes in land usage and industrial activitie's development have caused climate changes in different regions of the Earth. So studying these effects on rainfall process which is one of the most important components of water engineering studies. To considering ,extraordinary capabilities in chaos theory for modeling nonlinear and complex hydrological phenomena such as rainfall. In this study, monthly precipitation of Tabriz in the historical condition and climate change condition has been studied with this theory. For estimate lag time and phase state is using autocorrelation function and for chaos dimension applying correlation dimension method. Thus, the statistical period 1971-2000 as a historical period is chosen and the results of the LARS-WG model under two scenarios are (B1) and (A2) in three periods (2011-2030, 2046-2065 and 2080- 2099) as future periods. Results show historical period data with the fractal dimension of 5/96 which has a good chaotic nature. In scenario A2, three series of data, has chaotic nature and their fractal dimension is lower of historical data while in scenario B1, The three periods have stochastic behavior.

Afjeh and Lavarak sub-basins each with area of 4651,95 and 10557,2 hectare are located at south border of central Alborz at north-eastern of Tehran. Various formations basically contains Shaly, Sandstone, Conglomerate and tuff lithology, covered this region more than igneous rocks. In Afjeh sub-basin, Barout formation with the age of Cambrian and in Lavarak sub-basin, Mila formation with the age of middle and late Cambrian, are the oldest available stones and the newer stone units belong to Quaternary period in each of them. The purpose of this research is to compare MPSIAC and EPM models in calculation of sediments supply and soil erosion, using GIS techniques. To achieve the goals, effects of lithology, soil texture and geological conditions on sediment production were considered by sedimentological and petrographic studies. Finally with use geostatisticaloperations, two models were compared. The results show that the most values of erosion are in Shaly, Marly, weathered tuff and alluvial deposits Parts of sub watersheds correlated with sensitive formations such as Karaj and Quaternary sediments. Based on map of MPSIAC model more than 75% of the total sub watersheds area was classified at class IV of erosion category with high sedimentation. Sub-basin’s erosion were calculated as 769.3 and 583.21 m2/km3 per year in Afjeh and Lavarak sub-basins by MPSIAC and 701. and 543.2 m2/km3 per year by EPM models, respectively. The results of statistical compare of erosion of MPSIAC and EPM models show that, there is no significant different between erosion estimate by MPSIAC model and real erosion measure, but the erosion estimate by EPM model have a significant different. So MPSIAC model may have better performance.

Increasing urban population and followed by the physical development of cities, explain how to control the development of towns and cities need to plan for future development based on sustainable development principles. Nir city in Ardabil province was located in 39 km west of Ardabil capital. In this study, locations and directions for future development based on land use planning has been evaluated. Determining of suitable land for development of normal variables using hierarchical process (AHP) in GIS (GIS) was used. These variables include the slope, topography, lithology, distance to faults, underground water depth, land use and the landform. Finally, with extraction of units and environmental assessment based on ecological criteria,potential capability was estimated for development in the study area. The results of this study showed that the most suitable development sites in the study area are located to the south. The results of this study showed that the combination of analytic hierarchy process and the ability of GIS to develop a reliable method to determine a suitable location can be used by researchers.

In the latest stage of Savalan volcano formation, the Magmatism following the Subsidence of caldera Cause the formation of acidic and intermediate Dooms and viscose lava flows along fractures and within the margin of Caldera. mainly having composed of plagioclase, clinopyroxene, amphibole, biotite, potassic feldspar and quartz, Textural and mineralogy relations that are observed in studied microscopic sections, such as glomeroporphyric and glomerochristic occurrence of Mafic minerals as well as the presence of non equilibrium textures such ac sieve texture, bimodal composition of phenocherists of plagioclase, heterogenic composition of matrix, presence of basic micro pillows and enclaves in a acidic rocks, zenolites with reactional rims and also scattering and different trends observed in the geochemical reveals that fractionation, magma mixing and crustal contamination has been play important role in formation of this magmas. On the other hand The intermediate rocks of the region form do to of the mixing of basaltic magmas with fractionated sections , that have been contaminated with Crust during the ascent phase. Base on Petrographic and geochemical evidence presented hear, we show that the acidic rocks vastly in the area have a different origin than andesitid and trachy andesitid lavas. Likely that these rocks are the result of partial melting of the crust, while the replacement of basic magmas in crustal magma mixing phenomena has also been made between the two.

In this study, the possibility of using mica for this application was investigated. First, mica gasket including small Phlogopite flakes with organic binders was used and its performance duringas leakage was simulated in a small set-up simulating fuel cell operating condition (air atmosphere, temperature of 800 C and time of 100 h). Due to heating of mica during operation, binders were burned out and remaining pores acted as leakage path. These leakage paths were filled by acid boric and the mica performance was enhanced up to 20%. The major leakage path (mica and its adjacent interface) was filled by a glass and a successful application of mica-glass layer was obtained for leakage prevention.

The purpose of this study is using reformed muhlbauer method in order to evaluate the pipeline environmental risk levels. In this method, the total index represents the hazard probability and the leakage factor represents the impact intensity. The final risk score is obtained by dividing the total score into leakage factor. 32 % of the pipelines contain very high risk and 11 % of the pipelines contain high risk. Medium risk belongs to 23 % of the pipelines and 34 % of the pipelines contain low risk. According to the results of kent malhauber method, the most important risk factor in this study is the High activity levels, low depth of coverage, lack of adequate education about the risks of pipelines to nearby residents, the lack of emergency messaging system, Intersection with multiple faults, Urban tissue, Population density and Valuable areas Like the National Natural.

One of the major problems in the integrated management of watersheds is soil erosion and Sediment. The control of this problem requires precise studies; quantitative data to determine critical and prone to erosion areas. Thus, an analysis of rate of erosion and sediment production using GIS techniques and experimental methods, such as EPM and MPSIAC seems necessary. In this study, we tried to use these two models to determine the amount of sediment and erosion-prone areas in the two sub watersheds overlooking the city of Tehran; Kan and Darakeh to recognize where necessary for conservation operations. Finally with use geostatics operations, two models were compared. The results show the most values of erosion are in Tuffy, Shaly Parts of sub watersheds correlated with sensitive formation such as Karaj. Based on map of MPSIAC model more than 50% of the total sub watersheds area was classified at class high of erosion category with 373.78 m3∕km2 per year for Kan and 483 m3∕km2 per year for Darakeh sedimentation. Sub-basins’ erosion were calculated as 683.2 m3∕km2 per year for Kan and 792.5 m3∕km2 per year for Darakeh by EPM models. The results of statistical compare of erosion of MPSIAC and EPM models show that, there is no significant different between erosion estimate by MPSIAC model and real erosion measure, but the erosion estimate by EPM model have a significant different. Som MPSIAC model may have better performance.