Sharif Digital Repository

In upstream oil industry, microorganisms arise some opportunities and challenges. They can increase oil recovery through microbial enhanced oil recovery (MEOR) mechanisms, or they can increase production costs and risks through reservoir souring process due to H2S gas production. MEOR is mostly known by bioproducts such as biosurfactant or processes such as bioclogging or biodegradation. On the other hand, when it comes to treatment of reservoir souring, the only objective is to inhibit reservoir souring. These perceptions are mainly because decision makers are not aware of the effect microorganisms’ cell can individually have on the wettability. In this work, we study the individual effect... 

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... 

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... 

The bacterial strain MJ01 was isolated from stock tank water of one of the Iranian south oil field production facilities. The 16S rRNA gene of isolate, MJ01, showed 99% similarity to Bacillus subtilis. The results revealed that biosurfactant produced by this strain was lipopeptide-like surfactin based on FTIR analysis. Critical micelle concentration of produced surfactin in distilled water was 0.06 g/l. Wettability study showed that at zero salinity surfactin can change original oil-wet state to water-wet state, but in seawater salinity it cannot modify the wettability significantly. To utilize this biosurfactant in ex situ MEOR process, economical and reservoir engineering technical... 

For microbial enhanced oil recovery (MEOR), different mechanisms have been introduced. In some of these papers, the phenomena and mechanisms related to biosurfactants produced by certain microorganisms were discussed, while others studied the direct impacts of the properties of microorganisms on the related mechanisms. However, there are only very few papers dealing with the direct impacts of microorganisms on interfacial properties. In the present work, the interfacial properties of three bacteria MJ02 (Bacillus Subtilis type), MJ03 (Pseudomonas Aeruginosa type), and RAG1 (Acinetobacter Calcoaceticus type) with the hydrophobicity factors 2, 34, and 79% were studied, along with their direct... 

This research study presents an experimental investigation on forced convection heat transfer of an aqueous ferrofluid flow passing through a circular copper tube in the presence of an alternating magnetic field. The flow passes through the tube under a uniform heat flux and laminar flow conditions. The primary objective was to intensify the particle migration and disturbance of the boundary layer by utilizing the magnetic field effect on the nanoparticles for more heat transfer enhancement. Complicated convection regimes caused by interactions between magnetic nanoparticles under various conditions were studied. The process of heat transfer was examined with different volume concentrations... 

The solar collectors have been commonly used in desalination systems. Recent investigations show that the use of a linear parabolic through collector in solar stills can improve the efficiency of a desalination system. In this work, a combination of a heat pipe and a twin-glass evacuated tube collector is utilized with a parabolic through collector. Results show that the rate of production and efficiency can reach to 0.27 kg/(m2 h) and 22.1% when aluminum conducting foils are used in the space between the heat pipe and the twin-glass evacuated tube collector to transfer heat from the tube collector to the heat pipe. When oil is used as a medium for the transfer of heat, filling the space... 

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,... 

Public concern over environmental issues such as ecosystem degradation is high. However, restoring coupled human-natural systems requires integration across many science, technology, engineering, management, and governance topics that are presently fragmented. Here, we synthesized 544 peer-reviewed articles published through September 2020 on the desiccation and nascent recovery of Lake Urmia in northwest Iran. We answered nine questions of scientific and popular interest about causes, impacts, stabilization, recovery, and next steps. We find: (1) Expansion of irrigated agriculture, dam construction, and mismanagement impacted the lake more than temperature increases and precipitation... 

Background: The burden of inflammatory bowel disease (IBD) is rising globally, with substantial variation in levels and trends of disease in different countries and regions. Understanding these geographical differences is crucial for formulating effective strategies for preventing and treating IBD. We report the prevalence, mortality, and overall burden of IBD in 195 countries and territories between 1990 and 2017, based on data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017. Methods: We modelled mortality due to IBD using a standard Cause of Death Ensemble model including data mainly from vital registrations. To estimate the non-fatal burden, we used data...