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In the present study, the Soil and Water Assessment Tool (SWAT 2000) model was tested on both a monthly and yearly basis and applied to the Kordan Watershed, located in Iran. The main objective of the research was to assess the accuracy of the model in sediment-yield and surface water bicarbonate concentration estimation. The attributes of sub-watersheds, tributary channels and the main channel in each sub-watershed were generated using the Digital Elevation Model (DEM) and Geographical Information System (GIS) Arc View SWAT 2000 interface. The model was calibrated and validated for the period from 1990 until 2004. Calibration results revealed that the model predicted monthly and yearly sediment-yield, but not such good results were obtained for the bicarbonate concentration. Therefore, some efforts were made in order to find a solution for SWAT bicarbonate temporal modeling. Around 70 samples of the Kordan River water quality data were used and, upon doing statistical calculations, the best correlation between the average pH–EC of water and the bicarbonate concentration was obtained. The formula shall be tested at several watersheds, and it can also be defined to SWAT in order that the model is able to calculate bicarbonate concentration according to pH and EC of the river water, which are introduced to SWAT by the user as a stream water quality file (SWQ) .

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Regional impact studies of the future climate change effects are necessary because projected changes in meteorological variables differ from one region to another, and different climate systems can react in varied ways to the same changes. In this study, the effects of climate change on bioclimatic deficiency were compared in two cultivation methods (irrigated and rainfed) in a semi-arid region, Ahar (East Azarbaijan, IRAN). The agricultural land uses selected for evaluation were wheat (Triticum aestivum), alfalfa (Medicago sativa), sugar beet (Beta vulgaris), potato (Solanum tuberosum), and maize (Zea mays). In this way, Terraza model included in the land evaluation decision support system, called MicroLEIS DSS, was used. Terraza gives a quantitative prediction of a site bioclimatic deficiency. Soil morphological and analytical data were obtained from 44 sampling points based on a grid survey. Agro-climatic data, referred to temperature and precipitation, were collected from weather stations located in Ahar region, which benefits from more than 20 consecutive years of weather data. A future scenario of climate change was calculated according to the Intergovernmental Panel on Climate Change (IPCC) on regions of Asia under scenario A1FI (highest future emission) for 2080s. Although, increasing of precipitation being available by climate change in the future scenario, humidity index will be reduced because of high temperature. The results showed that climate change is likely to cause severe water stress in irrigated cultivation of alfalfa, sugar beet, potato, and maize, the use of irrigation methods being essential to maintain agricultural productivity. Although irrigation is indicated as very important in this regime of semi-arid agriculture, cultivation of rainfed wheat can be possible instead of the irrigated one. Also, it is revealed that climate perturbation effects on rainfed conditions are more serious than those on the irrigated conditions in the area.

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In present work, heat transfer and flow pattern map of dimpled and horizontal tubes were studied during phases of boiling and condensation of mandatory convection of hydrocarbon R600-a. Empirical relationship will be expressed based on empirical data obtained by such experiments and fit the experimental results and Matlab software to show flow pattern map for such refrigerant with proper accuracy. The cycle consists of a pump, two preheaters, two testing parts, two condensers, flow meter and reversing valve. In this study, experimental evaporator is a copper tube with internal diameter of 8.7 mm and length of 1200 mm. the heat required for fluid evaporation is supplied by thermal element twisted around it. Such tube has been designed in forms of dimpled and straight models to evaluate effect of placement of dimples inside tubes. The test was conducted by refrigerant mass flow between 155 and 470 kg/m^2 s and vapor quality between 0.05 and 0.78. Moreover, flow patterns and their transitions for refrigerant R-600a during flow boiling inside a helically dimpled tube and a smooth tube were visually observed and analyzed. Annular, intermittent, and stratified-wavy flow were recognized for plain tube whereas there was no stratified-wavy flow in flow pattern visualization of dimpled tube. Investigation clearly shows that the dimples in evaporation significantly impact the two phase flow pattern. Inside the helically dimpled tube the intermittent/annular transitions occurs at lower vapor quality value than for the smooth tube.

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 Optimum cropping pattern increases productivity where input resources are limited. An optimized cropping pattern was developed for a region in Moghan Plain, located in the northwestern Iran, to help water supplier in pre-season decision making on water and land allocation. AquaCrop simulation model was calibrated and executed for yield predictions for 11 different crops and 13 diverse soil types. Evaluation of AquaCrop model showed great robustness for a broad range of crops, even for the crops like canola and alfalfa that were undefined for the model. The precise generated crop water functions revealed the ideal conditions for water allocation by considering the impact of the existing limitation in monthly water availability on optimum cropping pattern without imposing any manipulation. Optimum cropping pattern based on water productivity (OCPWP) was identified by LINGO software. Integrating AquaCrop model and LINGO optimization problem solver created a Decision Support System (DSS) for technical analysis at the regional level. The created DSS is able to support the OCPWP in terms of the complex regional crop-mixture acreage. The ecological considerations introduced diverse winter crops to benefit from autumn precipitations. This strategy decreases irrigation requirement and saves some water for spring/summer high water-demanding crops like alfalfa and cotton, which generally enhances the system resiliency. The generated DSS revealed that 8,762 m³ water ha^-1 was required for optimum cropping pattern, which is 8% lower than the maximum and 3% more than the average available water.