Sharif Digital Repository

Elevated levels of nitrate (NO3) in groundwater systems pose a serious risk to human populations and natural ecosystems. As part of an effort to remediate NO3 contamination in irrigated stream-aquifer systems, this study elucidates agricultural and environmental parameters and processes that govern NO3 fate and transport at the regional (500 km2), local (50 km2), and field scales (<1 km2). Specifically, the revised Morris sensitivity analysis method was applied to a finite-difference nitrogen cycling and reactive transport model of a regional-scale study site in the lower Arkansas River valley in southeastern Colorado. The method was used to rank the influence of anthropogenic activities and... 

In this study, four types of tetrabutylphosphonium carboxylate ionic liquids (ILs) were synthesized and used for a one-pot transesterification of wet Chlorella vulgaris (C. vulgaris) microalgae into fatty acid methyl esters (FAME) in the presence of methanol, as well as refined oils (sunflower, canola, and corn oil). The resulting process removed the need for complete drying and lipid extraction steps typically needed for biodiesel production from microalgae. The leading candidate ionic liquid catalyst, tetrabutylphosphonium formate ([P4444][For]), was further optimized using response surface methodology to minimize material consumption, increase water compatibility, reduce processing time... 

Nowadays, one of the most important challenges in developing greenhouses is meeting their energy demand. The other challenge is the high water consumption of evaporative-cooling systems in arid and semi-arid regions. In this study, a integrated dynamic model is developed to determine the greenhouse relative humidity, carbon dioxide, and temperature, considering transpiration. The model is applied to a greenhouse utilizing a ground to air heat transfer system, located in the Alborz province of Iran and the results are validated with experimental data. Energy and water performance of the greenhouse are evaluated for the case study greenhouse. Then, the model is applied to a greenhouse (similar... 

Irrigation is not well represented in land surface, hydrological, and climate models. One way to account for irrigation is by assimilating satellite soil moisture data that contains irrigation signal with land surface models. In this study, the irrigation detection ability of SMAP enhanced 9 km and SMAP-Sentinel 1 (SMAP-S1), 3 km and 1 km soil moisture products are evaluated using the first moment (mean) and the second moment (variability) of soil moisture data. The SMAP enhanced 9 km soil moisture product lacks irrigation signals in an irrigated plain south of Urmia Lake, whereas SMAP-S1 products record irrigation signal in soil moisture variability. Despite observing higher variability... 

One of the main challenges in arid and semi-arid regions is the lack of water for various purposes such as industrial and agricultural applications. The problem is even more significant in traditional agriculture. The geographical location, climatic conditions, average annual rainfall, vegetation, air pollution and turbidity, and canopy of plants are important and lead to different water consumption in plants. Therefore, proper water consumption in agriculture in most countries leads to food security and a better supply of crops. In this research, we propose a fuzzy system that has eight inputs and seven outputs. Inputs include soil moisture, relative humidity, air temperature, wind speed,... 

Iranian water authority has recently announced that one of the effective ways to avoid unprecedented high water consumption in Iran's agriculture sector is to increase water price. This paper analyzes the feasibility of this policy by using a hydro-economic approach with the aim to consider the role of water pricing in agricultural water management. Such an analysis was conducted through comparing price of water consumed for producing selected agricultural crops (i.e. wheat, sugar beets, onion, tomato, barley, potato, corn, alfalfa hay and watermelon) in a case study on two provinces (East Azarbaijan and West Azarbaijan) in Iran to that in the state of California (CA) in the USA. According...