Hydrogeochemical evolution of groundwaters with excess fluoride concentrations from Dashtestan, South of Iran   总被引：2，自引：2，他引：0  

S. Battaleb-Looie  F. Moore  H. Jafari  G. Jacks  D. Ozsvath 《Environmental Earth Sciences》2012,67(4):1173-1182

Hydrogeochemical investigations were carried out in the Dashtestan, the eastern part of Borazjan, with a focus on fluoride content. The study area is underlain by a complex geology that is dominated by three lithological units, namely marl, alluvial sediments, and carbonate rocks. To assess the major geochemical factors controlling the fluoride enrichment in water, 37 groundwater and 12 surface water samples were collected from the three lithological units. Fluoride concentrations ranged up to 3?mg/L, and average concentrations varied from 1.12 (in carbonate aquifers) to 1.73 (in alluvial aquifers) to 1.82?mg/L (in marl aquifers). To study the influence of rocks and soils on groundwater quality, an additional 41 soil and rock samples were also taken and analyzed for fluoride. The order of average fluoride content in both rocks and soils is: marl?>?alluvial sediments?>?limestone, which confirms that marl is a likely source of fluoride.  相似文献   

Late Santonian–Early Maastrichtian calcareous nannofossils from marly deposits near Kerman (Central Iran)     

Akram Pouresmaeil  Fatemeh Hadavi 《Arabian Journal of Geosciences》2013,6(4):1203-1213

For the first time, the calcareous nannofossils of marly deposits near Kerman (Bardsir area) have been studied. This study presents the integrated (calcareous nannofossils) biostratigraphy of the Bardsir section in the Kerman basin, Central Iran. In most parts of Central Iran, the Upper Cretaceous sequence is complete and continuous and is divided into two groups: Cenomanian–Touronian flysch and Campanian–Maastrichtian flysch. Flyschs composed of sets of green marl sequences (Coniacian–Santonian) have been separated to reduce the basin depth and refer to the relative calm. Bardsir is located 57.6 km from Kerman (Central Iran). The lithology of this area includes light green marl with layers of calcareous siltstone, limestone, and flysch rocks. In this study, 24 samples were taken and prepared with smear slide. Most species were photographed with a light microscope. As a result of this study, 30 genera and 42 species of nannofossils have been identified. A high-resolution calcareous nannofossil biostratigraphic study has been carried out, allowing the division of the studied section into eight biozones of Late Santonian to Early Maastrichtian age (CC17–CC24).  相似文献   

Fishery-induced Inter-annual Changes in the Mean Trophic Level,the Northern Sea of Oman off the Iranian Coast, 2002–2011     

Sakineh?Mashjoor  Fatemeh?Heidary?Jamebozorgi  Ehsan?KamraniEmail author 《Ocean Science Journal》2018,53(4):655-665

Ecosystem-based management is one of the most important approaches that may lead to reducing the impacts of fishing on ecosystems. In this context, we have assessed the impact of Iranian coastal fishing (using landing data of 49 exploited species) on the ecosystem of the North Sea of Oman (Sistan and Baluchestan Province), during the last decade (2002–2011), with emphasis on testing the occurrence of the “fishing down? phenomenon. The Mean Trophic Level (MTL) and Fishing-in-Balance (FiB) index are two indicators that we used for analysis. The data indicated that the increased total landings in this region might be related to the exploitation of marine fishery resources especially with regard to large pelagic fish. Over the past decade, moderate decreasing trends in MTL and an increasing trend in the FiB-index were observed. In this regard, an upward trend in the spatial expansion factor and also a downward trend in the piscivory index and in Primary Production Required (PPR) in the time period could all indicate a spatial expansion toward deep waters, the catching of the large pelagic piscivorous species, such as tuna, and a sign of fishing pressures on the ecosystem. The results suggest a range of fishery exploitation patterns throughout the food web but it seems that these patterns are not a consequence of ?fishing down?. We suggest that the monitoring research be continued in this region and these indicators should be used to make fisheries management decisions and to prevent the continuance of this trend in future.  相似文献   

Prediction of riverine suspended sediment discharge using fuzzy logic algorithms, and some implications for estuarine settings     

Saeed Jafari Mianaei  Ali Reza Keshavarzi 《Geo-Marine Letters》2010,30(1):35-45

The ability of fuzzy logic algorithms to model relationships between stream flow and suspended sediment discharge was investigated using daily measurements of stream flow and suspended sediment discharge for the Escanaba River mouth station, situated on the shore of Lake Michigan and operated by the US Geological Survey. Three different configurations of inputs were applied, whereby the inputs were fuzzified into fuzzy subsets of variables by means of triangular membership functions. The relationships between inputs and suspended sediment discharge (output) were represented by a set of fuzzy rule expressed in IF–THEN format. The weighted average method served for defuzzification. The commonly used sediment rating curve was also applied to the data, and its performance compared with that of the three models by means of statistical analyses. For all three models, suspended sediment discharge predicted by the fuzzy logic algorithm was in satisfactory agreement with observations. Furthermore, the fuzzy logic algorithms performed better than the sediment rating curve, particularly at higher rates of suspended sediment discharge (in this study, more than 50  × 10⁶ g/day). Considered collectively, the use of fuzzy logic algorithms is suggested as a simple and effective approach for better prediction of suspended sediment discharge, also for estuaries.  相似文献   

Flash flood susceptibility mapping using a novel deep learning model based on deep belief network,back propagation and genetic algorithm     

Himan Shahabi  Ataollah Shirzadi  Somayeh Ronoud  Shahrokh Asadi  Binh Thai Pham  Fatemeh Mansouripour  Marten Geertsema  John J.Clague  Dieu Tien Bui 《地学前缘(英文版)》2021,12(3):146-168

Flash floods are responsible for loss of life and considerable property damage in many countries.Flood susceptibility maps contribute to flood risk reduction in areas that are prone to this hazard if appropriately used by landuse planners and emergency managers.The main objective of this study is to prepare an accurate flood susceptibility map for the Haraz watershed in Iran using a novel modeling approach(DBPGA) based on Deep Belief Network(DBN) with Back Propagation(BP) algorithm optimized by the Genetic Algorithm(GA).For this task, a database comprising ten conditioning factors and 194 flood locations was created using the One-R Attribute Evaluation(ORAE) technique.Various well-known machine learning and optimization algorithms were used as benchmarks to compare the prediction accuracy of the proposed model.Statistical metrics include sensitivity,specificity accuracy, root mean square error(RMSE), and area under the receiver operatic characteristic curve(AUC) were used to assess the validity of the proposed model.The result shows that the proposed model has the highest goodness-of-fit(AUC = 0.989) and prediction accuracy(AUC = 0.985), and based on the validation dataset it outperforms benchmark models including LR(0.885), LMT(0.934), BLR(0.936), ADT(0.976), NBT(0.974), REPTree(0.811), ANFIS-BAT(0.944), ANFIS-CA(0.921), ANFIS-IWO(0.939), ANFIS-ICA(0.947), and ANFIS-FA(0.917).We conclude that the DBPGA model is an excellent alternative tool for predicting flash flood susceptibility for other regions prone to flash floods.  相似文献   

Thermal comfort evaluation in Tehran metro using Relative Warmth Index   总被引：2，自引：2，他引：0  

M. Abbaspour Ph.D.  M. J. Jafari  N. Mansouri  F. Moattar  N. Nouri  M. Allahyari 《International Journal of Environmental Science and Technology》2008,5(3):297-304

Underground railway systems, can generate heat from their operations to raise the temperatures of carriages and the station substantially. This may lead to passenger discomfort and complain especially in warm weather conditions that prevail in Tehran if underground environment is not cooled. Transportation air conditioning Committee of American Society of Heating, Refrigerating and air-conditioning Engineers proposed the Relative Warmth Index for thermal comfort design and investigation in subway environment. In this research, thermal comfort at Tehran metro stations and carriages of lines 1 and 2 has been studied using this index. The measurements were taken during two periods of September 2006 and July 2007 at different zones of stations. For this purpose, temperature, relative humidity and air velocity were measured at different times. The status of the air-conditioning systems together with passenger traffic was also recorded. A total number of 231 measurements including 114 and 117 measurements were carried out in September 2006 and in July 2007 respectively. The measurements in September 2006 did not exceed the thermal limit. However, it did exceed in July 2007. In comparison, with thermal comfort level of metros all over the world, Tehran Metro stands in an acceptable condition, while the maximum capacity of air-conditioning systems was not used, if so the thermal comfort condition would be better.  相似文献   

Groundwater risk mapping prediction using mathematical modeling and the Monte Carlo technique   总被引：1，自引：0，他引：1  

Fatemeh Jafari  Saman Javadi  Golmar Golmohammadi  Kourosh Mohammadi  Ahmad Khodadadi  Mohsen Mohammadzadeh 《Environmental Earth Sciences》2016,75(6):491

  相似文献   

Prediction of rainfall using artificial neural networks for synoptic station of Mashhad: a case study     

Najmeh?Khalili  Saeed?Reza?KhodashenasEmail author  Kamran?Davary  Mohammad?Mousavi?Baygi  Fatemeh?Karimaldini 《Arabian Journal of Geosciences》2016,9(13):624

In this paper, we have utilized ANN (artificial neural network) modeling for the prediction of monthly rainfall in Mashhad synoptic station which is located in Iran. To achieve this black-box model, we have used monthly rainfall data from 1953 to 2003 for this synoptic station. First, the Hurst rescaled range statistical (R/S) analysis is used to evaluate the predictability of the collected data. Then, to extract the rainfall dynamic of this station using ANN modeling, a three-layer feed-forward perceptron network with back propagation algorithm is utilized. Using this ANN structure as a black-box model, we have realized the complex dynamics of rainfall through the past information of the system. The approach employs the gradient decent algorithm to train the network. Trying different parameters, two structures, M₅₃₁ and M₇₄₁, have been selected which give the best estimation performance. The performance statistical analysis of the obtained models shows with the best tuning of the developed monthly prediction model the correlation coefficient (R), root mean square error (RMSE), and mean absolute error (MAE) are 0.93, 0.99, and 6.02 mm, respectively, which confirms the effectiveness of the developed models.  相似文献   

Effects of irradiated Ergosan on the growth performance and mucus biological components of rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>     

Najmeh Sheikhzadeh  Fatemeh Chehrara  Marzieh Heidarieh  Katayoon Nofouzi  Behzad Baradaran 《中国海洋湖沼学报》2016,34(1):13-18

Effects of irradiated and non-irradiated Ergosan extract (alginic acid) on rainbow trout growth performance and skin mucosal immunity were compared. Ergosan was irradiated at 30 kGy in a cobalt-60 irradiator. A total of 252 fish (128.03±9.4 g) were randomly divided into four equal groups, given the basal diet either unsupplemented with Ergosan (control group) or supplemented with crude Ergosan (5 g/kg), ethanol-extracted Ergosan (0.33 g/kg) or irradiated Ergosan (0.33 g/kg) according to this protocol: basal diet for 15 days, treatment diet for 15 days, basal diet for 10 days and treatment diet for 15 days. Highest growth performance was observed in fish fed irradiated Ergosan (P <0.05). Dietary administration of different Ergosan types did not cause any changes in mucus protein level, but improved alkaline phosphatase level and hemagglutination titer compared with the control (basal diet without Ergosan) on day 55 of feeding trial (P <0.05). Furthermore, the highest value of lysozyme activity was observed in gamma-irradiated Ergosan on day 55. In conclusion, gamma-irradiated Ergosan at 0.33 g/kg was found to improve growth performance and mucus biological components significantly in comparison with the control group (basal diet without Ergosan).  相似文献   

Investigation on the Distribution of Gold Across the Ahar Area (NW Iran) Using Stream‐Sediment and BLEG Methods          下载免费PDF全文

Vartan Simmonds  Fatemeh Jahangiryar  Mohssen Moazzen  Ahmad Ravaghi 《Resource Geology》2016,66(2):213-225

The Ahar area is located in NW Iran. The main part of the area is covered by Eocene andesitic and andesi‐basaltic rocks within which several granitoid intrusives of Oligocene age are emplaced. This caused vast hydrothermal alterations and Cu and Au mineralization. In this regard, this contribution aims to explore the distribution of gold across the region based on systematic sampling of stream sediments and using the secondary geochemical halos, as well as the bulk leach extractable gold (BLEG) method. Meanwhile, the results obtained from these two methods will be compared in order to find out if the anomalous zones match with each other. For this, 620 stream sediment samples of ?80 mesh grain size and 422 BLEG samples were collected and analyzed by Fire Assay and atomic absorption spectroscopy (AAS) methods, respectively. For BLEG samples, gold was first dissolved using KCN before being analyzed by the AAS method. Furthermore, 84 rock samples were also collected during the field control surveys and were analyzed by Fire Assay and ICP‐OES methods for gold and other elements, respectively. After determining the distribution characteristics and statistical parameters of gold in each group of samples, anomaly maps of gold for each method were prepared, revealing almost similar anomalous zones across the region. Based on these maps, most of the discovered anomalies correlate well with granitoid intrusives of Oligocene age and the related hydrothermal alterations, which have occurred within the intrusives and the host andesitic‐basaltic rocks of Eocene age, especially at the NE and central parts of the area and east of Ahar. Some silicic veins and veinlets have been observed during field surveys in these parts, within which high concentrations of Au and sometimes Cu are determined. Another anomalous zone is located over the hydrothermal alterations within trachy‐andesitic and andesitic volcanics of Pliocene age at the SE part of the quadrangle, where vast alterations caused by volcanic fumaroles and epithermal mineralization of gold and Pb–Zn is discovered. In this regard, the SE and NE parts of the area and the east Ahar area are proposed, in order of importance, for further detailed investigations.  相似文献