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Climate change, in addition to increasing temperature, causes changes in the duration, intensity, form, and timing of rainfall in different parts of the Earth, which can cause droughts and floods. It also changes the volume, duration, and runoff duration, which will bring about many developments and changes in the water-resource management (Kamal and Massah Bavani, 2009). In order to reduce inconsistencies, studying the impacts of climate change on water resources is necessary. One of the most widely used models for these future studies is Atmosphere-ocean General Circulation Models (AOGCMs) (Wilby and Harris, 2006). In general, most studies present a high degree of uncertainty as a result of using AOGCMs in the simulation of climate change and hydrology parameters. the outputs of simulated water-resource models under climate change could be relied on when the uncertainties are taken into account at all stages (Semenov and Stratonovitch, 2010). In order to innovate the research method, in this study 10 AOGCMs under three greenhouse gas emission scenarios (A1B, A2, and B1) were used in the simulated range of hydro-climatic variables through climatic models and downscaling methods in the Dez Oliya basin during 2040-2069. In Summary, when reviewing the range of hydro-climatic variable changes in the future period, it could be observed that the uncertainty of AOGCMs under all three emission scenarios is greater than the downscaling methods.

Introduction The Alborz structural zone in northern Iran is the host of a number of important coal deposits. The Gheshlagh coal mine is one of them, which is located 35 km southeast of Azadshahr. Coal bearing strata in the Gheshlagh mining district occur in the middle part of the Lower Jurassic Shemshak Formation which consists mainly of shales, siltstones and sandstones. The Geshlagh coals have a low sulfur content and a low ash yield. The ash content of coal and its geochemical character depends on the environment of deposition and subsequent geological history (Yazdi and Esmaeilnia, 2004). The purpose of this study was to investigate the texural and mineralogical characteristcs of the Ghashlagh coals and to identify the geochemistry of the major and trace elements and their relationship to specific mineralogical components. These results are necessary to improve the understanding of coal characterization and to relate the mineralogy of different materials to their potential for producing acidic or alkaline mine waters associated with mining and preparation processes. Materials and methods About 20 samples were collected from the main coal seams. These samples were taken from fresh faces of the mine to avoid weathered surfaces and get fresh samples. The petrography of the samples was carried out by the conventional microscopic methods at the Golestan University. Mineralogical analyses were done by a X-ray diffractometer equipped with a CuKα tube and monochrometer (XRD Philips PW 1800) at the Kansaran Binaloud Company. The coal samples were initially crushed to less than 200 μm and homogenized. Then, 50 g from each sample was heated to 525 oC according to the United States Geological Survey procedure(Bullock et al., 2002). The concentration of the major and trace elements in the resulting ash samples was determined using a wavelength Xray fluorescence spectrometer (XRF Philips PW1480) at the Kansaran Binaloud Company. Results The Coal-bearing formation in the Ghashlagh mine belongs to the clastic unit of the Shemshak Formation, consisting mainly of about 2400 m sandstone, siltstone, shale. The middle part of this formation includes the economic coal beds. Petrographic and mineralogical investigations indicate that the dominant mineral phases of the Gheshlagh coals are quartz, kaolinite, montmorillonite, albite, muscovite, illite and pyrite. Pyrite occurs as euhedral to anhedral crystals and locally as framboids which are disseminated in the coal. Oxidation products consist mainly of iron hydrosulfate resulting from the oxidation of pyrite. The organic/inorganic affinity of elements in coal was determined using the correlation coefficient between the elements and ash yeild. Si, Al, Ti, Fe, K, Na, Ga, Zr, Rb and Nb are mainly associated with minerals. Sr, Pb and Ni have a dual association. The concentrations of most trace elements in the Gheshlagh coal samples are high when compared with the usual reported range in the world. The contents of Pb and Ni show the highest concentrations. Discussion The Gheshlagh coals are characterized by relatively low amount of sulfur indicating deposition in lacustrine and swamp environments (Goodarzi et al., 2006). The concentration of Ni, V, Sr, Ba and Ce in the Gheshlagh coals are relatively higher than the Shahroud and Lushan coals (Yazdi and Esmaeilnia, 2004). The comparison of the concentration of trace elements in the Gheshlagh coals and worldwide concentrations (Swaine, 1990) indicates the enrichment of Ni and Pb in the Gheshlagh coals. Gluskoter et al. (1977) used a value of six times the Clarke value to determine if an element is enriched in the whole coal. By these criteria, the concentration of Ni and Pb are enriched in the Gheshlagh coals when compared with the Clarke values. Generally, the distribution and abundance of reacting mineral species in the coal mines can be used to predict the extent of acidification and neutralization in particular area. In the Gheshlagh coal mine, the frequency of pyrite is moderately low. In addition, the availability of carbonates in the host rocks provides buffering capacity for acid produced by oxidation in this area. This investigation has led to a better understanding of coals and their roof and floor lithologies in the Gheshlagh coal mine. Acknowledgment The authors wish to thank the Iran Minerals Production and Supply Company (Project No. 30716) and the Department of Geology, Faculty of Sciences at the Golestan University for financial assistance and all necessary resources needed to carry out this research. References Bullock J.H., Cathcard J.D., and Betteron W.J., 2002. Analytical methods utilized by the United States analysis of coal and coal-combustion products, Geological Survey for the United States Geological Survey, Denver, Report 389, 15 pp. Gluskoter H.J., Ruch R.R., Miller W.C., Cahill, R.A., Dreher G.B., and Kuhn J.K., 1977. Trace elements in coal: occurrence and distribution, Illinois State Geological Survey, Illinois, Report 499, 115 pp. Goodarzi F., Sanei H., Stasiuk L.D., Bagheri- Sadeghi H., and Reyes J., 2006. A preliminary study of mineralogy and geochemistry of four coal samples from northern Iran. International Journal of Coal Geology, 65 (1-2) 35-50. Swaine D. J., 1990. Trace Elements in Coal, Butterworths, London, 278 pp. Yazdi M., and Esmaeilnia A.S., 2004. Geochemical properties of Coal in the Lushan Coalfield of Iran, International Journal of Coal Geology, 60 (1) 73-79.

Climate change is a serious challenge to human interest by its adverse effect on various sectors, such as water sources, agriculture, and energy. According to IPCC report, the average annual temperature of the earth has been raised between 0.3 to 0.6º because of the spread of the greenhouse gases, and this report predicts this amount will increase between 1 to 3.5º until 2100(Boberg et al ,2010). To study the effect of greenhouse gases in the atmosphere and the oceanic-atmospheric, general circulation model in regional scale is the most efficient vehicle. These models have been developed to simulate the current climate. They also performed well in predicting future changes in the climate and simulating interactions of soil, atmosphere, and oceans (IPCC, 2007). The effect of climate change on water sources is assessed using rainfall-runoff models by simulating hydrological processes. Studying future climate change and its likely events will help planners and water sources administrators to cope with the future challenge. Considering these likely changes will contribute to objective planning toward optional operations. Predicting future runoff value is one of the most important factors about dam construction, water transferring, agricultural growth and industrial activities.  Semenov (2008) assessed LARS-WG performance by data from 20 representative stations. Babaeian et al, (2004) and Khaliliaqdam, et al( 2013), studied the effect of climate change on the hydroelectric reservoir of Jor Dam by the microclimate model LARS-WG and scenarios B1, B2, and A1B. Output results of the model showed that Tmin and Tmax will increase to the amount of o.3-0.6 degrees. As a result, available water reservoirs of behind the dams for hydroelectric generation are affected by the decreased rainfall. BaniHabib et al, (2016), simulated the input flow of Shahcheraghi Dam using the generator LARS-WG, data downscaling, and the function of artificial neural networks on output of LARS. They found that nightly and daily temperatures rise 1.1 and 1.2 degrees from 2015 to 2040, and rainfall will decrease by 9% during January. By simulating artificial neural networks, it was determined that the input flow will experience 2.4-4.1 % decrease based on different scenarios.

Along with the numerous developments and facilities for constructing large dams, there is a need for developing design and construction methods for systems that can correctly discharge the floods. Weirs refer to any barrier across a channel that raises the flow level and accelerates the flow when flowing over it (Abrishami and Hoseini, 2011). Piano key weirs are the newest type of long-crest weirs and one of the best solutions for modifying the existing weirs. Reducing the energy of the flow over the weirs before their transfer downstream is a solution for preventing possible damage to the structure itself and downstream structures as well as the excess costs incurred by the builders of hydraulic structures due to constructing strong protective structures (Katourani, 2012). Lempèrière and Ouamane (2003) described the piano key weirs and stated their advantages compared to other conventional nonlinear weirs as the ability to place the weir in the crest of the reservoir dam and thus increasing the specific flow rate. Erpicum and Machieles (2011) compared the energy dissipation between two different geometries for a piano key weir and a spillway weir. Concerning the application of a block, the tests and results obtained by the US Land Renewal Organization indicate that using large blocks that separate the flow jet and create turbulence can effectively dissipate the kinetic energy of the current.

Introduction and purpose: Energy consumption is on a rapidly growing trend in the world. Accordingly, the non-renewable energy sources are expected to be run out in the future. This issue has resulted in the establishment of efforts targeted toward the development of new energy-generating methods around the world. Biogas energy is one of the new and clean energies that is produced from the anaerobic digestion of biomass wastes. Anaerobic digestion is a cost-effective and environment-friendly method, which facilitates fertilizer and biogas production as well as landfill leachate treatment. Given the high environmental hazards of leachate and its mixture with animal wastes, the present study aimed to estimate the possibility of producing biogas in various mixture ratios. Methods: In this pilot-scale experimental study, the landfill leachate of Mashhad, Iran, were mixed with caw fresh dung in different ratios, but same conditions, under anaerobic digestion. This was conducted to consider the ability to produce methane gas in different proportions and landfill leachate. At the beginning and end of the project, the parameters of EC, pH, VS, TS, COD, TOC, P, K, N, and Na were measured. Additionally, the composition of the gases produced under different operating conditions was analyzed using gas chromatography mass spectrometry. Results: Gas production began three weeks after uploading and continued for five weeks. The analysis of gas production in three ratios was indicative of the CH4 production in all three proportions. In this regard, 1/1 ratio produced the highest percentage of CH4. No gas production was observed in the two months of study. Other physical and chemical parameters, such as COD, TS, TKN, and TOC were reduced in the given mixtures during the biogas production procedure. For instance, the case with 1/1 ratio, which showed the best results, had almost 80% decrease in the given parameters. However, no gas production or change of parameters were observed in the control sample (leachate), which was examined for two months. Conclusion: The findings of the study revealed the possibility of producing biogas out of the mixture of waste leachate and animal wastes. Biogas reduces the risk of waste leachate disposal to the environment and facilitates the production of fertilizers containing nutrients (e.g., Na, K, N, and P), which are standard regarding such parameter as pH, EC, C/N, and reduced VS. Moreover, these gases are cost-effective and environment-friendly.

Background and Objectives: Nowadays, indicators related to human physiology have special roles in human bioclimatic and environmental studies. One of these indices is Physiological Equivalent Temperature (PET). In the present study, trends of physiological equivalent temperature index over the past half century, which is the foundation of plans, especially in the field of health and environment, were evaluated in four climatic regions of Iran (Mashhad, Rasht, Esfahan, Tabriz and Bandar Abbas). Material and methods: In this study, the data required to calculate the heat stress in the daily scale for 50 years during 1961-2010 were obtained from Iranian Meteorological Organization. Then, PET index at the daily scale was calculated and values greater than 35°C were identified for warm periods of the year. In the next step, the seasonal trends were analyzed by Mann-Kendall test. Results: Changes in the frequency of days with heat stress in stations of Mashhad, Isfahan, and Tabriz have been rising during spring and summer. In other words, the greatest amount of positive change has occurred over the long-term average in these cities. The highest frequency of hot days was observed in Rasht and Bandar Abbas stations. The main reason for this subject has to do with how adjacent they were to the sea and the high rate of evaporation in such areas. Conclusion: The 1980s-1990s have been allocated as the most days of hot stress. Upward trend of thermal stress occurring in the studied stations has increased the attention to the problem of heat stress and disease (thermal attack, fainting, muscle cramps) from the field of planning and management of the crisis.

In the present study, CanESM2 climate change model and stormwater management model (SWMM) were employed to investigate the climate change effects on the quantity and quality of urban runoff in a part of Karaj watershed, Alborz Province. The base period (1985-2005) and future period (2020-2040) are considered for this purpose. Based on the existing main and lateral drainage system and to be more accurate, the watershed was divided into 37 sub-watersheds by ArcGIS software. To simulate rainfall-runoff, the intensity-duration-frequency (IDF) curve has been prepared for a 2-hour duration and 10-year return period, for the base period and RCP2.6 and RCP8.5 climate change scenarios based on the obtained precipitation data from Karaj synoptic station. Results showed that mean 24-hour precipitation values in RCP2.6 and RCP8.5 scenarios will increase by 21% and 11%, respectively, and maximum 24-hour precipitation values will decrease by 17% and 23%, respectively, as compared to the observed values in the base period. Also, based on the results of quantitative and qualitative runoff modeling in the study watershed, and according to the outflow hydrograph in the RCP2.6 and RCP8.5 scenarios, the outlet runoff discharge will decrease by 5.8% and 7.1%, respectively. Also, the flooded areas in the watershed will decrease by 13% and 15.28%, respectively. The concentration of pollutants in the RCP2.6 and RCP8.5 scenarios, compared to the base period, including total suspended solids (TSS), will increase by 7.48% and 9.24%, total nitrogen (TN) will increase by 6.93% and 8.48%, and lead (Pb) will increase by 7.32% and 8.91%, respectively.

Iran is located in the North Temperate Zone from 25 to 40 degrees latitude and 44 to 63 degrees longitude, with a total area of approximately 1,650,000 Km2. A 50% of total lands area is covered with high mountain ranges. Elevations range from 26 meters below sea level on the shores of the Caspian Sea to 5860 meters above sea level at the pick of the Mt. Damavand. Drought or water deficiency is one of the most critical climatic factors in Iran. About 50% of Iran can be classified as arid or semi-arid zones. Climate parameters, particularly precipitation varies significantly in different parts of the country. There is not a good annual rainfall distribution in most regions of Iran, which limits the plant development and growth. Not only high temperature in southern, central and lowlands of Iran is a limiting factor, but also low temperature in northern, western and highlands is another limiting factor too. The Caspian region receives the largest part of the country’s precipitation while the central desert (Dasht-e-Lut) is faced with permanent drought. Forest ecological zones in Iran could be categorized as: a) North, Caspian forest, b) West, Zagros forest, c) North West, Arasbaran forest, d) South, Subtropical forest in Persian Gulf areas, and e) Central, Scattering forests. Some of the main tree species of Caspian forests: Fagus orientalis, Carpinus betulus, Acer velutinum, Quercus castaneifolia, Fraxinus excelsior. In this study, whole forest areas in southern part of Caspian Sea were monitored by study on vegetation map and visiting field. Three points representing major part of Hyrcanian Forests were selected from wet part in west to drier part in east. Four meteorological stations data used for investigation. Most of climatic factors including maximum, minimum and mean annual temperature; daily and annual precipitations were investigated. Mainly trends of mean annual temperature and annual precipitations were used for conclusion. It can clearly be concluded that during last half century climate in forest area in Caspian region become warmer. Precipitation trends especially in Anzali station that has highest precipitation records in Iran and also in Gorgan station have decreased. Precipitation trends in Rasht and Baboulsar stations have shown positive change. During last 49 years in Rasht station mean annual temperature increased about 1.28 °C and even its minimum temperature shows 2.45 °C increases. Increase mean annual temperature in Baboulsar station in last 54 yeas is about 1.44 °C and its minimum temperature shows 1.80 °C increases. Decrease of annual precipitation in Anzali station during last 54 years of records is about 409.4 mm and amount of decrease of precipitation for the period of last 53 years in Gorgan station is about 55.6 mm. Distribution of plants are directly depends upon temperature and precipitation conditions in each climatic zone. Generally with increasing about 100 meter of elevation amount of temperature will decrease by one degree of centigrade. In study zones especially in Gilan and Gorgan areas temperatures shown more than one degree increases and main species of vegetation cover moved upward about 100 meters. All data statistically were analyzed.

As wind power continues its rapid growth worldwide, Offshore Wind Turbines (OWTs) are likely to comprise a significant portion of the total production of wind energy. These kinds of wind turbines cause of their placement environment should resist in great stormy conditions, which cause fatigue failures. Fatigue loads are one of the main failure reasons in offshore structures. One of the best ways for decreasing these kinds of loads is reducing the structure vibration. In this research application of a tuned mass damper with different masses, in an offshore Tension Leg Platform (TLP) is investigated. Tuned Mass Dampers (TMDs) modeled in a developed code FAST-SC. Results show that using TMD in the nacelle can reduce the moments in the base of the tower and turbine vibration. This reduction can also increase time until failure factor of the OWTs.

In this paper, manufacturing and evaluation of ethanol gas sensors based on thin films of nanostructure tin oxide have been investigated. SnO2 thin films were prepared by both thermal evaporation (type I) and sputtering (type II) methods and heat treated on silicon wafer substrates. Scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD) and energy dispersive spectra (EDS) are employed to study the morphology and chemical composition of the semiconductor samples. Nano-scale grain size with homogenous distribution showed in SEM images of both types. Sensors resistance in air and its variation-transient response toward ethanol vapours (3000 ppm) was determinated. The response of the stable sensors was obtained 3 and 1.18 for type I and type II, respectively. That showes thin film of nanostructure tin oxide by thermal evaporation (type I) has better sensitivity than the other. More effective surface, adsorption sites and base-line resistance due to the more fine grain size in type I nanostructure, are its important reasons. however, it is slow due extensive rise time and fall time.