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    Forecasting Urban Groundwater Level Applying Geographical Information System (GIS) and Artificial Neural Network (ANN)

    , M.Sc. Thesis Sharif University of Technology Jazaei, Farhad (Author) ; Abrishamchi, Ahmad (Supervisor)
    Abstract
    Groundwater beneath the cities is becoming an important and valuable resource. Conjunctive use of surface and groundwater is likely to become increasingly more common as urban population grows by time. Therefore, one important requirement for urban water management planning is forecasting the groundwater level fluctuations. Unfortunately less experience and information is available to evaluate the fluctuations of groundwater level in urban environment compare to the natural systems, also different processes (sources) are involved in an urban water cycle, which all together make it more complicated to study. Similar to many other megacities, there is a serious lack of hydrogeological and... 

    Spatial-temporal Variation of Urmia Lake Basin Using Artificial Intelligence Algorithms

    , M.Sc. Thesis Sharif University of Technology Novin, Soroush (Author) ; Torkian, Ayoub (Supervisor)
    Abstract
    Water shortages resulting from macro-environmental climate changes as well as local inefficient agricultural practices and dam constructions activities have resulted in the gradual reduction of water level in Urmia Lake, located in the northwest of Iran. As such, restoration efforts were initiated to prevent further adverse impacts exacerbating the conditions and creating secondary problems such as regional salt dust generation and dispersion, resulting in health issues for the greater area population in the neighboring vicinities. The utilization of advanced forecast modeling based on deep learning algorithms can assist the authorities to manage better multi-dimensional issues affecting the... 

    Suppression of harmonic perturbations and bifurcation control in tracking objectives of a boiler-turbine unit in power grid

    , Article Nonlinear Dynamics ; Vol. 76, Issue. 3 , 2014 , pp. 1693-1709 ; ISSN: 0924090X Moradi, H ; Vossoughi, G ; Alasty, A ; Sharif University of Technology
    Abstract
    In the presence of harmonic disturbances, boiler-turbine units may demonstrate quasi-periodic behaviour due to the occurrence of various types of bifurcation. In this article, a nonlinear model of boiler-turbine unit is considered in which drum pressure, electric output and drum water level are controlled via manipulation of valve positions for fuel, steam and feed-water flow rates. For bifurcation control in tracking problem, two controllers are designed based on gain scheduling and feedback linearization (FBL). To investigate the efficiency of control strategies, three cases are considered for desired tracking objectives (a sequence of steps, ramps/steps, and a combination of them).... 

    Nonlinear dynamics and control of bifurcation to regulate the performance of a boiler-turbine unit

    , Article Energy Conversion and Management ; Vol. 68 , 2013 , pp. 105-113 ; ISSN: 01968904 Moradi, H ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
    Abstract
    The economical operations of power plants and environmental awareness are the major factors affecting the importance of control in boiler-turbine units. In this paper, a multivariable nonlinear model of boiler-turbine unit is considered. Drum pressure, electric output and water level of drum (as output variables) are adjusted at desired values by manipulation of valve positions for fuel, steam and feed-water flow rates (as input variables). Nonlinear dynamics of the unit is investigated through the concepts of bifurcation and limit cycles behaviour. In the presence of harmonic disturbances, some coefficients of the dynamic model, fuel and steam flow rates play as the bifurcation parameters.... 

    Using sliding mode control to adjust drum level of a boiler unit with time varying parameters

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis ; Vol. 5 , 2010 , pp. 29-33 ; ISBN: 9780791849194 Moradi, H ; Bakhtiari-Nejad, F ; Saffar-Avval, M ; Alasty, A ; Sharif University of Technology
    Abstract
    Stable control of water level of drum is of great importance for economic operation of power plant steam generator systems. In this paper, a linear model of the boiler unit with time varying parameters is used for simulation. Two transfer functions between drum water level (output variable) and feed-water and steam mass rates (input variables) are considered. Variation of model parameters may be arisen from disturbances affecting water level of drum, model uncertainties and parameter mismatch due to the variant operating conditions. To achieve a perfect tracking of the desired drum water level, two sliding mode controllers are designed separately. Results show that the designed controllers... 

    Role of exchange flow in salt water balance of Urmia Lake

    , Article Dynamics of Atmospheres and Oceans ; Vol. 65, issue , 2014 , pp. 1-16 ; ISSN: 03770265 Marjani, A ; Jamali, M ; Sharif University of Technology
    Abstract
    In this paper we examine how exchange flow in Urmia Lake plays a crucial role in dynamics of the lake. Urmia Lake, a very large hyper-saline lake of high ecological significance, is located in northwest of Iran with a 15-km causeway dividing it into north and south lakes. A 1250-m opening in the causeway near the east coast links the two lakes. The differences in mean water levels and densities of the two lakes increase in spring due to large freshwater inflows into the south lake. High evaporation dominates the lake in summer. By incorporating the results of a two-layer hydraulics theory into a mixing model of the lake, we show that the exchange flow through the opening diminishes the water... 

    Using satellite data to extract volume-area-elevation relationships for Urmia Lake, Iran

    , Article Journal of Great Lakes Research ; Volume 39, Issue 1 , March , 2013 , Pages 90-99 ; 03801330 (ISSN) Sima, S ; Tajrishy, M ; Sharif University of Technology
    2013
    Abstract
    Urmia Lake in the northwest of Iran is the second largest hyper-saline lake worldwide. During the past two decades, a significant water level decline has occurred in the lake. The existing estimations for the lake water balance are widely variable because the lake bathymetry is unknown. The main focus of this study is to extract the volume-area-elevation (V-A-L) characteristics of Urmia Lake utilizing remote sensing data and analytical models. V-A-L equations of the lake were determined using radar altimetry data and their concurrent satellite-derived surface data. Next, two approximate models, a power model (PM) and a truncated pyramid model (TPM), were parameterized for Urmia Lake and... 

    Nonlinear dynamics and control of bifurcation to regulate the performance of a boiler-turbine unit

    , Article Energy Conversion and Management ; Volume 68 , 2013 , Pages 105-113 ; 01968904 (ISSN) Moradi, H ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
    2013
    Abstract
    The economical operations of power plants and environmental awareness are the major factors affecting the importance of control in boiler-turbine units. In this paper, a multivariable nonlinear model of boiler-turbine unit is considered. Drum pressure, electric output and water level of drum (as output variables) are adjusted at desired values by manipulation of valve positions for fuel, steam and feed-water flow rates (as input variables). Nonlinear dynamics of the unit is investigated through the concepts of bifurcation and limit cycles behaviour. In the presence of harmonic disturbances, some coefficients of the dynamic model, fuel and steam flow rates play as the bifurcation parameters.... 

    Multivariable control of an industrial boiler-turbine unit with nonlinear model: A comparison between gain scheduling and feedback linearization approaches

    , Article Scientia Iranica ; Volume 20, Issue 5 , 2013 , Pages 1485-1498 ; 10263098 (ISSN) Moradi, H ; Alasty, A ; Saffar Avval, M ; Bakhtiari Nejad, F ; Sharif University of Technology
    Sharif University of Technology  2013
    Abstract
    Due to demands for the economical operations of power plants and environmental awareness, performance control of a boiler-turbine unit is of great importance. In this paper, a nonlinear Multi Input-Multi Output model (MIMO) of a utility boilerturbine unit is considered. Drum pressure, generator electric output and drum water level (as the output variables) are controlled by manipulation of valves position for fuel, feedwater and steam flows. After state space representation of the problem, two controllers, based on gain scheduling and feedback linearization, are designed. Tracking performance of the system is investigated and discussed for three cases of 'near', 'far' and 'so far' setpoints.... 

    Monitoring Urmia Lake area variation using MODIS satellite data

    , Article World Environmental and Water Resources Congress 2012: Crossing Boundaries, Proceedings of the 2012 Congress ; 2012 , Pages 1917-1926 ; 9780784412312 (ISBN) Sima, S ; Ahmadalipour, A ; Shafiee Jood, M ; Tajrishy, M ; Abrishamchi, A ; Environ. Water Resour. Inst. (EWRI) Am. Soc. Civ. Eng ; Sharif University of Technology
    ASCE  2012
    Abstract
    Urmia Lake is a large hyper-saline lake located in the northwest of Iran. It plays an important role in the hydrology, climate and ecology of its surrounding regions. In recent years, the water level of Urmia Lake has been dropped significantly. This study investigates the seasonal and annual variations of the lake area from 2000 to 2011 using remote sensing data. MODIS imageries of Normalized Differential Vegetation Index (NDVI) were used to extract the water surface area of the lake. Results reveal a significant decline in the lake area during the last past 12 years. Analysis of the seasonal images shows that maximum and minimum areas of Urmia Lake usually occur in winter and autumn,... 

    Investigation of humidity effect on the air refractive index using an optical fiber design

    , Article Journal of Applied Sciences ; Volume 11, Issue 16 , 2011 , Pages 3022-3027 ; 18125654 (ISSN) Mehrabani, A ; Golnabi, H ; Sharif University of Technology
    2011
    Abstract
    In this study operation of an optical design based on the intensity modulation for the refractive index change has been described. The reported instrument measures the transmitted output power depending up on the medium refractive index in the light path of a fiber-to-fiber design. A liquid cell is located between the fibers in the light path and power variations for different cold and hot water levels in the cell are measured. By using a reference humidity meter the calibration curve representing the relative humidity (%RH) as a function of the transmitted output power is obtained. For the hot water with the final temperature of T = 32.7°C the output power range of 255.0 -313.OnW is... 

    Using sliding mode control to adjust drum level of a boiler unit with time varying parameters

    , Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 5 , 2010 , Pages 29-33 ; 9780791849194 (ISBN) Moradi, H ; Bakhtiari Nejad, F ; Saffar Avval, M ; Alasty, A
    2010
    Abstract
    Stable control of water level of drum is of great importance for economic operation of power plant steam generator systems. In this paper, a linear model of the boiler unit with time varying parameters is used for simulation. Two transfer functions between drum water level (output variable) and feed-water and steam mass rates (input variables) are considered. Variation of model parameters may be arisen from disturbances affecting water level of drum, model uncertainties and parameter mismatch due to the variant operating conditions. To achieve a perfect tracking of the desired drum water level, two sliding mode controllers are designed separately. Results show that the designed controllers... 

    Design, construction and simulation of a multipurpose system for precision movement of control rods in nuclear reactors

    , Article Annals of Nuclear Energy ; Volume 37, Issue 12 , 2010 , Pages 1659-1665 ; 03064549 (ISSN) Musavi Shirazi, S. A ; Aghanajafi, C ; Sadoughi, S ; Sharifloo, N ; Sharif University of Technology
    Abstract
    This article presents the design and implementation of a microcontroller-based system for the automatic movement of control rods in nuclear reactors of either power or research types. This system is controlled automatically, is linked to a personal computer system, and has manual controlling ability as well. The important features of this system are: automatic scram of the control rods, activation of alarm in emergency situations, and the ability to tune the control rod movement course both upwards and downwards. In this system, a small tank has been improvised as a coolant reservoir for pool type reactors such as Tehran Research Reactor and its water level is continuously adjusted by... 

    Elitist continuous ant colony optimization algorithm for optimal management of coastal aquifers

    , Article Water Resources Management ; Volume 25, Issue 1 , 2010 , Pages 165-190 ; 09204741 (ISSN) Ataie Ashtiani, B ; Ketabchi, H ; Sharif University of Technology
    2010
    Abstract
    This paper presents an evolutionary based approach to achieve optimal management of a coastal aquifer to control saltwater intrusion. An improved Elitist Continuous Ant Colony Optimization (ECACO) algorithm is employed for optimal control variables setting of coastal aquifer management problem. The objectives of the optimal management are; maximizing the total water-pumping rate, while controlling the drawdown limits and protecting the wells from saltwater intrusion. Since present work is one of the first efforts towards the application of an ECACO algorithm, sharp interface solution for steady state problem is first exploited. The performance of the developed optimization model is evaluated... 

    A study on the key influential factors of a gas reservoir's potential for aqueous phase trapping

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 34, Issue 16 , 2012 , Pages 1541-1549 ; 15567036 (ISSN) Mirzaei Paiaman, A ; Dalvand, K ; Oraki Kohshour, I ; Masihi, M ; Moghadasi, J ; Sharif University of Technology
    Abstract
    Aqueous phase trapping in many oil and gas reservoirs is a noteworthy mechanism of formation damage during drilling, completion, work over, and stimulation operation. Aqueous phase trapping can limit the productivity of a well to a high extent, especially in low permeable gas reservoirs. In this article, using aqueous phase trapping laboratory tests on low permeable sandstone cores' effect of key factors on gas reservoir's potential for aqueous phase trapping was investigated. Studied factors were initial water saturation, permeability, water filtrate viscosity, and drawdown pressure. Results showed that severity of formation damage caused by aqueous phase trapping increases as each of the... 

    Assessment of underground karst caves using geophysical tests: A case study for lajamgir dam site, iran

    , Article Proceedings of the 5th International Conference on Geotechnical and Geophysical Site Characterisation, ISC 2016, 5 September 2016 through 9 September 2016 ; Volume 2 , 2016 , Pages 879-882 ; 9780994626127 (ISBN) Jafarzadeh, F ; Shahrabi, M. M ; Banikheir, M ; Eskandari, N ; Akbari Garakani, A ; Sedaghat Jahromi, H. F ; Sharif University of Technology
    Australian Geomechanics Society  2016
    Abstract
    Karst features have caused serious problems in many engineering projects because of their permeability and high leakage potential; a clear example is Lar Dam, 84 km northeast of Tehran in which normal water level has never been reached since the filling of its reservoir in 1980. Sometimes conventional methods of studying karst features (e.g., borings and sampling) fail to precisely reveal their underground structure and this may result in inaccurate design, extensive leakage and creation of sinkholes. In the present paper, an under-study dam site in Lajamgir, Zanjan province, northern Iran is investigated. Ground observations indicated the possibility of presence of Karst caves while borings... 

    Resiliency via integrated coastal management in Kish Island

    , Article Scientia Iranica ; Volume 23, Issue 4 , 2016 , Pages 1708-1718 ; 10263098 (ISSN) Pak, A ; Majd, F ; Mohammadi, M ; Sharif University of Technology
    Sharif University of Technology  2016
    Abstract
    Small islands around the world face various hazards such as sea-water level rise, hurricanes, human activities over pressure, environmental degradation, and pollution. Resiliency is a critical feature that has to be maintained in these sensitive and vulnerable areas. This paper focuses on the importance of Integrated Coastal Management (ICM) in increasing the level of resiliency in small islands. Integrated Coastal Zone Management (ICZM) has been recommended for practice by United Nations 1992 Rio Conference resolution to conserve the valuable natural resources of the coastal areas around the globe and improve their deteriorating environmental conditions. Integrated coastal management plan... 

    Improving the performance of a nonlinear boiler–turbine unit via bifurcation control of external disturbances: a comparison between sliding mode and feedback linearization control approaches

    , Article Nonlinear Dynamics ; Volume 85, Issue 1 , 2016 , Pages 229-243 ; 0924090X (ISSN) Moradi, H ; Abbasi, M. H ; Moradian, H ; Sharif University of Technology
    Springer Netherlands 
    Abstract
    Boiler–turbine units may show quasiperiodic behavior due to the bifurcation occurrence in the presence of harmonic disturbances. In this study, a multi-input–multi-output nonlinear dynamic model of a boiler–turbine unit is considered. Drum pressure, electric output, and fluid density are the state variables and adjusted at the desired values by manipulation of the input variables. Control inputs are the valve positions for fuel, steam and feed-water flow rates. To improve the quasiperiodic behavior of the system and bifurcation control in tracking problem, two controllers are designed: feedback linearization control and nonlinear sliding mode control (SMC). The feedback linearization... 

    Multivariable optimal control of an industrial nonlinear boiler–turbine unit

    , Article Meccanica ; Volume 51, Issue 4 , 2016 , Pages 859-875 ; 00256455 (ISSN) Moradi, H ; Vossoughi, G ; Sharif University of Technology
    Abstract
    Performance control of a boiler–turbine unit is of great importance due to demands for the economical operations of power plants and environmental awareness. In this paper, an optimal control strategy is designed to achieve the desired performance of a boiler–turbine unit. A multivariable nonlinear model of a utility boiler–turbine unit is considered. By manipulation of valves position for the fuel, steam and feed-water flows; output variables including the drum pressure, electric output and fluid density (and consequently drum water level) are controlled. Performance measure of the problem is defined such that the control efforts are minimized while the tracking objectives are obtained. In... 

    Simulation of wave generated by landslides in Maku dam reservoir

    , Article Prediction and Simulation Methods for Geohazard Mitigation - Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation, IS-KYOTO 2009, 25 May 2009 through 27 May 2009 ; 2009 , Pages 91-96 ; 9780415804820 (ISBN) Yavari Ramshe, S ; Ataie Ashtiani, B ; Sharif University of Technology
    Abstract
    In this work, impulsive wave generation and propagation generated by landslides are studied numerically for a real case. Maku dam reservoir, in the northwestern of Iran is considered as the case study. Generated wave heights, wave run-up, maximum wave height above the dam crest and the probable overtopping volume have been evaluated, using a two-dimensional numerical model (LS3D). This model is validated using available three-dimensional experimental data for simulating impulsive wave caused by sub-aerial landslides. Based on the results, the generated wave height for first and second scenarios are 12 m and 18 m respectively. The wave height of 8 m is observed close to dam body. Because of...