Sharif Digital Repository

Incline in the population and civilization, development of agriculture, and expansion of industries, in addition to limitations on surface and groundwater resources necessitate the existence of correct and efficient planning of management and utilization of water resources. Prediction of behavioral models of changes in water resources systems, influenced by utilizing strategies, absolutely helps stakeholders for conservative development of these resources. System dynamics is an object oriented method that is based on system's feedback. Not only it gives real description of complex systems, but also it provides the ability to influence effectively in development of the model for the user. The... 

Environmental flows supply critical contributions to wetland health and economic development, while wetlands are one of the richest ecosystems due to diversity of the ecological species. The Shadegan Wetland is the located in the south-west of Iran, at the top of the Persian Gulf. It is the largest wetland of the country with an area of almost 400,000 hectares. The wetland plays a significant role, both hydrological and ecological in the natural functioning of the northern coast of the Gulf. Moreover, Shadegan Protected Zone is of high economic and social importance, as its vegetation is assumed the main source of feeding the wildlife species. On the other hand, the wetland has the potential... 

This work presents a quick method in estimation of spring back effect in sheet metal forming. In this method, the so called Inverse Finite Element Method (IFEM) has been adopted for compution of strains and also blank shape. Although the of element used is membrane, the effect of bending/ unbendiing is considered by addition of some extra forces as the bending forces to the nodal forces. The results of strain distribution obtained by IFEM are applied to another algorithm developed for computation of the spring back . this algorithm has been developed for the sections with plane starin assumption. Therefore, spring back of longitudinal parts, can be estimated by this method in a short time.... 

Terrestrial water storage change is an important factor in a region ecosystem studies and climate variability effects. Terrestrial water storage is composed of water on vegetation surfaces, in the biomass, in the unsaturated soil or rock zone, as groundwater, snow and ice, and as surface water in rivers, lakes, reservoirs and wetlands. There was no possibility to monitor and estimate this volume of water and it's changes during past decade because of lack of global processing system. After a successful launch, the GRACE mission developed by NASA is currently mapping the variations of the gravity field of the Earth over its lifetime.
The aim of this study is to investigate Terrestrial... 

In designing of sheet metal forming processes, knowledge of the maximum permissible strains in the sheet is of prime importance for the design engineer. Thus, a large amount of experimental and theoretical researches have been carried out to estimate these limiting strains. A renowned and prevalent theoretical method for prediction of forming limits is the Marciniak and Kuczynski model. In this model, it is assumed that a small groove exists in the sheet even before applying the loads; and due to the weakness of this region, necking starts from there. The major problem of the M-K model is requiring of an experimental point to “calibrate” the results. Furthermore, while experiments indicate... 

Forecasting model of water consumption amounts could be used in order to manage water resources for future condition of city. In this thesis, a model for forecasting water demand for Tehran has been presented by evaluating regression models and intelligent models. In this study, uncertainties which are connected to climate and population changes are taken into account. The considered variables include minimum, maximum and medium temperature, precipitation and solar radiation. Considering objectives of this thesis and various forecasting methods and their advantages and regional conditions of Tehran, in addition to regression analysis, perceptron neural network, probabilistic neural network... 

Industry Success leads to the use of fossil fuels in communities that result to climate change in the world. Among these effects, there is the effect on the severity, extent and duration of precipitation. Hydroelectric plants are clean and cheap energy resources in the world that due to the use of water, the phenomenon of climate change are very impressionable. Regarding high costs of construction and maintenance of these dams in order to exploit their lengthy; Impact of climate change on them is important issue.
In this research, first a nonlinear optimization model to maximize hydroelectric power generation by genetic algorithms in the MATLAB software environment has been developed.... 

Over time, human needs more groundwater to meet agricultural, industrial, and urban uses; so the study on factor affecting groundwater and groundwater level changes are important for water resource management. However, often forgotten is the fact that accurate and reliable predictions are based on a correct diagnose of the past. One of the questions here is how the climate has changed since the last. Such a question is largely related to detection. Purpose of detecting climate variability and climate change, identifying climate variability and trends in system and describe the factors causing these changes are. Without knowing and understanding these changes and fluctuations, we are not able... 

Several countries in the Middle East – North Africa (MENA) region have been always faced drought in their histories, so they implementing many strategies to manage vital water resources for many years. Because of the volume of water available for food production has not been sufficient to meet increasing demands, it has became a critical issue today, to optimize the consumption of water. One of the best policies is to use financial tools to adjust the water usage.In this research we have studied the effects of two scenarios on the volume of water consumption. The firs scenario is to increase the water price, and we have studied the consumers’ reactions. The second scenario is to lend the... 

In designing sheet forming processes, finding out the value of the maximum strain before necking in sheets is extremely important. Therefore, many experimental and theoretical efforts have been carried out in order to answer this question. One of the most well-known and useful theoretical methods in this regard is the Marciniak - Kuczynski method which was introduced in 1967 and is still the topic of many researches. In this model, it is assumed that a groove as a defect primarily exists in the sheet and due to the weakness of this region, necking will initiate. Furthermore, the effects of various parameters such as sensitivity to strain rate, strain path, thickness, three dimensional... 

In today’s advanced world it was only in 1970s that business ethics emerged. However, some of the dimensions of business are dated back to the medieval times. Business ethics has also part of its roots in Greek civilization BC and the orient civilization.The explaining religion of Islam and verses of Quran contain a great deal of codes of conduct on honesty, loyalty, prohibition of treason, bribery and use of short weights, respect for justice, etc. Therefore, we, as Iranians and heirs of the ancient Iranian and Islamic civilizations, shall put more effort into revitalization of moral codes. The purpose of this research is to express the importance of ethics in business and also the... 

Using a combination of groundwater and surface water, is defined as each project planned by combining these two sources which, in most cases, will achieve greater benefits than the non-integrated. The benefit is a set of privileges that technically, economically and environmentally justify the project. One of the prevalent and effective problems of fertile and flat plains of Khuzestan province, especially the Evan plain, is lack of proper drainage of agricultural land downstream of dams and irrigation networks which are covered by. In this plain also, according to statistics from Piezometers, the groundwater level is rising. At the first, the aim of this study is to study the current... 

There is increasing demand for water due to rising world population. In addition, lower supplies of water under varying hydrological condition because of changing climate, renders further stress on an already over-allocated water resource. Thus, this condition would exacerbate water supply-demand conflicts resulting in penalties on local economy. On the other hand fresh water as a scarce resource requires comprehensive management. To maintain fresh water resources, systems need principles of ecologically sustainable development that keeps environmental uses as legal. Hence, in this situation there is a need to develop appropriate methods to minimize the climate change consequences and... 

Drought is a common phenomena which has a lot of unwanted conse-quences on human being life and environment. Drought forecasting plays a significant role in water resources and environmental systems. Considering IRAN inappropriate location which is on the arid and semi-arid area of the earth and Widespread damages which are related to drought during recent years in iran; importance of developing an accurate model by using new technologies becomes quite inevitable. In the last decay Neural Networks have appeared very useful in non-Stationary and non-linear time Series forecasting and modeling.
This study is about to use conjunctive model of adaptive neuro fuzzy inference system and... 

Worldwide coverage, online accessibility and unique accuracy of spatial and temporal satellite data such as rainfall, has encouraged researchers to apply this information in studies such as water resources engineering, hydrologic modeling, drought studies and flood forecast. This research aims to introduce a method that reduces the estimation error of rainfall data derived from a satellite product. “Satellites rainfall products” such as PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks), which has been used in this research, has significant error in comparison with geo-prediction precipitation, due to stochastic and systematic errors. In... 

In the rolling process some parameters may cause the rolling process to be asymmetric, the most important of this parameters are unequal radii, friction and rotational speed of upper and lower rolls. The mentioned asymmetry factors change the symmetric rolling process to the new process called asymmetrical rolling process. Asymmerical roling process that caused from various asymmetry factor have been studeid for many years by various researchers from different directions with different methods.Among the most important of which was raised by many researchers, slab method was the most accuracy and acceptable method. Using the slab method researchers were able to calculate the force, torque and... 

In recent decades, the importance of theoretical and experimental researches on sheet metal forming has been revealed due to its wide-spreading applications. The purpose of these researches is to optimize the forming processes and minimize the existing imperfections. Since classical theories don’t include parameters for describing the dependence of metals behavior on size effects or inhomogeneous plastic deformation effects, gradient theories are considered in many researches. In gradient theories, this dependence is considered by changing the constitutive equations and the existence of higher order of strain gradient in zones with inhomogeneous deformation. By considering the localized and... 

In the classical theories of plasticity, plastic deformation of material is modeled with a macro- scopic viewpoint and without considering the existing physical mechanisms at the crystal scale. However, plastic deformation stems from slip phenomena and evolution of crystalline structure. Furthermore the effects of initial texture of material on its mechanical properties, like formability, and also texture evolution of material can only be calculated by considering these physical mecha- nisms.The main purpose of this thesis is to predict forming limit diagrams of sheet metals based on crystal plasticity approach by considering the effect of initial material texture and presentation of... 

This project is about crest triangular weirs. The discharge is a function of triangular angle and head of the water. There are so many projects that is about the effect of various parameters on the discharge of weir. In some places we can not use just one symmetric weir so we have to use multi weirs. Because of the lack of information in multiasymmetrical weirs, the goal of this project in studing multi triangular weirs in laboratory. We used the civil engeneering department of sharif university chanel that is 148 cm in width and 40 cm in height. In this project we used three 60, two 90 and two 45 triangular weirs that instaleed singular,double and triapple in various position in width. In... 

This study presents an image processing technique for automatic strain and stress measurement in sheet metals. In order to measure the strain automatically, the sheet blank is electrochemically etched to create circular and rectangular grids. After press forming of the sheet, circular grids are deformed into elliptical grids and rectangular grids are deformed into quadrilateral grids. Different photos are captured for using in image processing technique. These photos are taken in different positions. Finally strain can be measured by processing these photos and the stress is obtained by using Levy-Mises flow rule. In this study, three methods of image processing technique are simultaneously...