Sharif Digital Repository

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... 

Lake surface temperature is an important indicator of the lake state and a driver of regional weather and climate near large lakes. The objective of this study is to use thermal imagery from the MODIS on board the Earth Observing System Terra and Aqua platforms to assess the spatial and temporal variations in Urmia lake temperature. Urmia Lake, located in northwestern Iran is one of the largest permanent hypersaline lakes in the world. The surface temperature of Urmia Lake is examined between 2008 and 2009, as dry years. MODIS-derived lake SWT then was calibrated with monthly observations. MODIS-derived lake SWT exhibits a cool bias (-0.72°C) relative to in situ temperature observations in... 

The Shadegan Wetland is a Ramsar-listed wetland in the south-west of Iran at the head of the Persian Gulf. It is the largest wetland of Iran covering about 400,000 hectares. The wetland plays a significant hydrological and ecological role in the natural functioning of the northern Gulf. It also supports a very diverse flora and fauna and is the most important site in the world for Marbled Teal. The water regime is threatened by upstream abstraction of water for irrigation and the saline discharge from sugar cane industries and irrigation schemes. This will result in an overall reduction in wetland water quantity and quality, leading to a change in plant community composition. This paper... 

Remote sensing is an effective tool for capturing spatial and temporal variations of water surface temperature (WST) in large lakes. The WST of Urmia Lake in northwestern Iran was examined from 2007 to 2010, using MODIS land surface temperature (LST) products. Spatial and temporal (diurnal, monthly, seasonal and inter-annual) variations of Urmia Lake WST were also investigated. Results indicate that the MODIS-derived WSTs are in a good agreement with the in situ data (R2=0.92 and bias=-0.27). Spatial analysis of WST revealed that there are three thermal zones along the lake: the shallow region in barriers of the causeway, islands and the shoreline; the south part; and the deep north parts.... 

This study investigates critical run-off and sediment production sources in a forested Kasilian watershed located in northern Iran. The Water Erosion Prediction Project (WEPP) watershed model was set up to simulate the run-off and sediment yields. WEPP was calibrated and validated against measured rainfall-run-off-sediment data. Results showed that simulated run-off and sediment yields of the watershed were in agreement with the measured data for the calibration and validation periods. While low and medium values of run-off and sediment yields were adequately simulated by the WEPP model, high run-off and sediment yield values were underestimated. Performance of the model was evaluated as... 

In this study design and operation of invasive and non-invasive cylindrical capacitive sensor (CCS) designs for the electrical measurements of water, water solutions, and water mixtures are reported. Operation of the capacitance measurement module for such probes is based on the charge/discharge method. The measured capacitances and resistances for distilled water, mineral water, tap water and salt water samples are reported by using two sensor types and results are compared. The measured capacitance by invasive CCS for distilled water is about 2.28 μF and by non-invasive CCS is 31.40 pF, which shows a big difference for different probes. Such a difference is due to the electrical... 

Environmentally responsive surface-modified nanoparticles are colloidal nanoparticles coated with, at least, two physicochemically distinct surface groups. Recent advances in the synthesis and production of nanoparticles have enabled the production of environmentally responsive surface-modified nanoparticles with both hydrophilic and hydrophobic surface groups. These nanoparticles act like colloidal surfactants. In this paper, environmentally responsive surface-modified silica nanoparticles are synthesized and used for enhancement of oil recovery. For this purpose, silica nanoparticles are coated with polyethylene glycol chains as hydrophilic agent and propyl chains as hydrophobic agent at... 

In this study by using a Cylindrical Capacitive Sensor (CCS), the Electrical Conductivity (EC), effects on the capacitance measurements of the water liquids was investigated. Theoretical values of the capacitance measurements of water liquids with the cylindrical length in the range 0.5-5 cm are calculated. Our obtained results indicate that measured capacitance value by CCS depends on the liquid capacitance and reactance capacitance. Liquid capacitance value of the distilled water for permittivity of 80 is about 33.5 pF and reactance capacitance value is about 0.290 μF, when the cylindrical length value is about 1.6 cm. The reactance capacitance for the mineral, tap and dilute salt water... 

In this study by using a capacitive cell probe the temperature variation of the electrical properties of the water liquids is investigated. Variation of the reactance capacitance parameter of liquids with temperature in the range of 17-60°C is measured for the plain water and water mixtures. The temperature variations of the capacitance for the cool distilled and tap water samples are studied for the range of 17-29°C obtained. Present results indicate an averaged variation of 4.69 μF/°C for the distilled water and 3.24 μF/°C for tap water in warm up process to a near room temperature. The cooling behaviors for the warm mineral, tap and salt water liquids are also investigated in this study.... 

A reciprocating single-chamber micropump is designed and experimentally tested. The actuation technique of the pump is based on Lorentz force acting on an array of low-weight microwires placed on a flexible membrane surface. A square-wave electric current (5.6 and 7.8 A) with a low-frequency range (5.6 to 7.6 Hz) is applied through the microwires in the presence of a perpendicular magnetic field (0.08 to 0.09 T). The resultant oscillating Lorentz force causes the membrane to oscillate with the same frequency, and pushes the fluid to flow toward the outlet using a high-efficiency ball-valve. The micropump has exhibited a maximum efficiency of 2.03% with a flow rate as high as 490 μl/s and... 

In the context of stationary power generation, fuel cell based systems are being predicted as a valuable option to tabernacle the thermodynamic cycle based power plants. In this paper, multi objective optimization approach is used to optimize the planer solid oxide fuel cell (SOFC) stacks performance using genetic algorithm technique. Multi objective optimization generates the most attractive operating conditions of a SOFC system. This allows performing the optimization of the system regarding to two different objectives. Two pairs of different objectives are considered in this paper as distinguished strategies. In the first strategy, minimization of the breakeven per-unit energy cost... 

The interaction between design parameters and operation variables is a complex problem that affects system techno-economic performance. The aim of this paper is to optimize the design and operation of an SOFC/MGT integrated system. The problem consists of design and operation optimization of an integrated SOFC/MGT system. Decision variables including design parameters (number of SOFC cells) as well as the operation parameters (air pressure ratio, methane and air flow rates). The multi objective approach using genetic algorithm is applied considering two pairs of proposed objectives: (1) maximization of output power and minimization of the electricity cost and (2) maximization of system... 

In this paper, a methodology for energy management system (EMS) based on the multi-objective receding horizon optimization (MO-RHO) is presented to find the optimal scheduling of hybrid renewable energy system (HRES). The proposed HRES which is experimentally installed in educational building comprising the PV panels, wind turbine, battery bank and diesel generator as the backup system. The data acquisition system provides input profiles for receding horizon optimizer. A mixed-integer convex programing technique is used to achieve the optimal operation regarding to two conflicting operation objectives including diesel fuel cost and battery wear cost. The Pareto frontiers are presented to... 

In this work, a novel convex sequence framework for real-time receding horizon operation optimization of a hybrid renewable energy system integrated with optimal sizing is presented to increase the penetration rate of renewable energy in supplying the demand. The proposed framework optimizes the entire lifetime cost of a system consisting of two main steps which are 1) design & installation and 2) operation as two sequence modules. This framework is applied to a hybrid renewable energy system which includes PV, wind turbine, batteries and a diesel generator. In the operation optimization, receding horizon strategy is used to optimize the operation schedule. Mixed integer convex programming... 

In this study, operation of the contact Cylindrical Capacitive Sensor (CCS) for the reactance capacitance measurement of the water liquids by using the charge/discharge measurement module is investigated. The effect of geometric factor on the capacitance measurement of different liquid samples is also studied. The measured capacitances for the distilled, mineral, tap and salt water samples are reported by using two contact CCSs with the active length of 16 and 74 mm. The measured capacitances by small contact CCS for the saltwater is 1.76 uF and by big contact CCS is 47.8 uF, which shows a big difference for different probes. In another study, the effects of the liquid conductance on the...