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All-Optical Scalable Multi-stage Interconnection Network for Data Centers
, M.Sc. Thesis Sharif University of Technology ; Koohi, Somayeh (Supervisor)
Abstract
According to the increasing amount of data exchanged among data centers, the need for speeding up and bandwidth and reduced power consumption has been increased. The information show that about 77% of the data is moved into the data centers. On the other hand, 10% of data center’s power consumption is used to data transmission. Improving the interconnection network of data centers can play an important role in reducing power consumption and speeding up. In recent years, optical interconnects have gained attention as a promising solution. Nevertheless, offering an all-optical and efficient architecture is an important issue. In this study, we intend to provide a multi-stage, all-optical...
Adopting Dynamic Topology for Energy Management in Optical Interconnection Networks in Data Centers
, M.Sc. Thesis Sharif University of Technology ; Koohi, Somayeh (Supervisor)
Abstract
Today with the deployment of cloud computing and web applications; We need to have powerful datacenters with provisioning high bandwidth. Current data centers with electronic network interconnects, using excessive power to provisioning requisite bandwidth. Nevertheless, interconnecting networks in data centers isn’t in maximum efficiency and many components of them aren't used efficiently. So it is necessary to use an optical network with dynamic provisioning variable bandwidth and energy management. In this approach, our proposed architecture is designing topology with adopting dynamically for energy management in optical interconnect networks in data centers. To achieve this we can study...
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) ; 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...
Monitoring temperature changes in a hypersaline lake using MODIS-derived water temperatures (the case of Urmia Lake, Iran)
, Article 6th International Symposium on Environmental Hydraulics, Athens, 23 June 2010 through 25 June 2010 ; Volume 2 , 2010 , Pages 881-886 ; 9780415595469 (ISBN) ; Tajrishy, M ; Sharif University of Technology
2010
Abstract
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...
Water allocation for wetland environmental water requirements: The case of Shadegan wetland, Jarrahi catchment, Iran
, Article World Environmental and Water Resources Congress 2006: Examining the Confluence of Environmental and Water Concerns, Omaha, NE, 21 May 2006 through 25 May 2006 ; 2007 ; 0784408564 (ISBN); 9780784408568 (ISBN) ; Tajrishy, M ; Sharif University of Technology
2007
Abstract
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...
Modelling Evaporation & Salinity Variation in Saline Lakes Using Spatial System Dynamics: The Case of Urmia Lake
,
Ph.D. Dissertation
Sharif University of Technology
;
Tajrishy, Masoud
(Supervisor)
Abstract
Evaporation is the most important water loss from terminal lakes which can influence the chemistry of lakes. In large lakes, the spatial distributions of meteorological and water quality variables affect the evaporation rates. Therefore, it is crucial to consider such variations in estimating evaporation rates from large lakes. This study aims at developing an evaporation estimation model for saline lakes considering salinity and spatial distribution of variables in/over the lakes and investigating the interaction between meteorological, hydrological and water quality variables in natural saline systems. To accomplish these objectives, first a distributed model was developed for estimating...
Mapping surface temperature in a hyper-saline lake and investigating the effect of temperature distribution on the lake evaporation
, Article Remote Sensing of Environment ; Volume 136 , 2013 , Pages 374-385 ; 00344257 (ISSN) ; Ahmadalipour, A ; Tajrishy, M ; Sharif University of Technology
2013
Abstract
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....
Application of the WEPP model to determine sources of run-off and sediment in a forested watershed
, Article Hydrological Processes ; Volume 29, Issue 4 , 2015 , Pages 481-497 ; 08856087 (ISSN) ; Meghdadi, A. R ; Sima, S ; Sharif University of Technology
John Wiley and Sons Ltd
2015
Abstract
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...
Feasibility Analysis of Backflow Detection in Lobe Blowers in Khuzestan Steel Plant using Condition Monitoring Techniques
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)
Abstract
Lobe blowers are positive displacement machines (PDM) that are widely used in various industries. The efficiency of lobe blowers depends on the clearance between fixed and moving parts. If the clearance between the parts increases, backflow occurs, which means that the flow returns from the high-pressure zone of the outlet to the low-pressure zone of the inlet, and this makes the blower not have the initial efficiency and work with a lower capacity than its design. This research is carried out with the aim of checking the feasibility of backflow detection using two condition monitoring methods, including ultrasonic and thermography techniques. The sample of this research includes seven...
Low-cost reciprocating electromagnetic-based micropump for high-flow rate applications
, Article Journal of Micro/ Nanolithography, MEMS, and MOEMS ; Volume 14, Issue 3 , July , 2015 ; 19325150 (ISSN) ; Salari, A ; Shafii, M. B ; Sharif University of Technology
SPIE
2015
Abstract
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...
Comparison of Vibration and Ultrasonic Signal Performance in Predicting the Remaining Useful Life of Rolling Element Bearings
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)
Abstract
The prediction of Remaining Useful Life (RUL) has become a critical tool in enhancing the availability of rotating machinery. By knowing the remaining time before a bearing failure occurs during operation, significant reductions in unplanned production downtimes and associated costs can be achieved. In this study, by analyzing the time signals of vibration and ultrasonic data related to the bearing of a 4.1 MW electromotor from installation to replacement, and by investigating the behavior trends and correlation between extracted features, RMS has been ultimately identified as the health indicator in both vibration and ultrasonic techniques for monitoring the bearing’s condition. First,...
Improvement of Aqueous Electrolyte for use in Calcium Ion Batteries
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor) ; Askari, Masoud (Supervisor)
Abstract
Nowadays, along with the increasing development of renewable energy sources such as solar and wind, the need to use cost-effective fixed energy storage systems with cyclic stability at high rates is increasing. Due to their abundance and high safety, aqueous rechargeable calcium-ion batteries have the potential to meet the growing needs of stationary energy storage devices. In addition, they can be produced at low cost and have a higher volume capacity. However, the electrochemical stability window, which is controlled by the hydrogen production reaction on the anode and the oxygen production reaction on the cathode, severely limits the application of electrode materials in aqueous...
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)
Abstract
Bearings play a critical role in the functionality of rotating equipment across various industries, accounting for approximately 50% of equipment failures due to bearing malfunctions. Accurate life prediction of bearings is essential not only for preventing unexpected breakdowns and subsequent damage but also for minimizing unnecessary replacements of functional bearings, which can lead to increased operational costs. With the rise of artificial intelligence, numerous predictive models have been developed; however, many of these require extensive datasets, which are often unavailable in industrial settings. Data collection is typically irregular, based on the sensitivity of the equipment,...
Identification of Possible Failures in Online Data of Gas Turbines based on Information Fusion using Artificial Intelligence
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)
Abstract
Gas turbines' safe operation depends on the monitoring of performance thresholds and equipment limitations. This is accomplished through online data monitoring using sensors, with the collected data processed by monitoring software supplied by turbine manufacturers to extract information on operating conditions. The thresholds are usually set during manufacturing under standard conditions and saved in the control software. As the turbine ages and undergoes maintenance, these thresholds and operating conditions may change, requiring expert analysis to determine safe operating limits. Technological advancements have enabled the processing of operational data to establish patterns and create...
Reliability and Redundancy Analysis at a Methanol Plant in the Khark Petrochemical Complex: Investigation, Modeling, and Improvement
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Somayeh (Supervisor) ; Saniee Monfared, Mohammad Ali (Supervisor)
Abstract
Today, reliability assessment of production systems is crucial for ensuring continuous production and minimizing operational and maintenance (O&M) costs. One way to assess reliability at the system level is to create a reliability block diagram (RBD) and estimate the failure rates of equipment over their operational periods. This approach has been utilized in this thesis, focusing on assessment of the reliability of various units within the methanol plant at Khark Petrochemical Complex. In this context, understanding the condition of the equipment criticality is essential for constructing the reliability block diagram. The Crespo model and total criticality per risk (CTR) measure have been...
Experimental investigation on laminar forced convection heat transfer of ferrofluids under an alternating magnetic field
, Article Experimental Thermal and Fluid Science ; Volume 49 , 2013 , Pages 193-200 ; 08941777 (ISSN) ; Dibaei, M. H ; Hakim Sima, A ; Shafii, M. B ; Sharif University of Technology
2013
Abstract
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...
A Proper Method of Upscaling Permeability data in a Typical Iranian Reservoir
, M.Sc. Thesis Sharif University of Technology ; Shadizadeh, Reza (Supervisor) ; Jonoud, Sima (Co-Supervisor)
Abstract
In this paper we have tried to mention a proper method of upscaling permeability data in a typical Iranian reservoir. Firstly a literature review is made on some common upscaling methods witch have been used so far. We introduced common upscaling methods like full tensor method, streamline method, stone method , vertical equilibrium method and also Kyte & Berry method. Additionally we have explained their advantages and also disadvantages. After selecting two upscaling methods, Kyte & Berry method and vertical equilibrium method, we applied these algorithms for upscaling of permeability data of Soroosh Oil Field. Soroosh oilfield is a heavy oil, Iranian reservoir located in Persian Gulf....
The Investigation of the Effectiveness of Engine Oil Filter Particle Analysis in Enhancing the Efficiency of Diesel Engine Condition Monitoring Programs
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Masoodi, Alireza (Supervisor) ; Mohammadi, Somayeh (Co-Supervisor)
Abstract
Over the years, as machines have been invented, their maintenance and repair have consistently been regarded as critical concerns. Oil analysis techniques are an effective method for monitoring the condition of mechanical equipment. Since filters in these devices continually absorb and remove a significant portion of particles from the lubricant, the selection of appropriate filters is crucial. While filters positively affect machine performance, they can also negatively impact oil condition monitoring. To mitigate this negative effect and improve the predictive accuracy of equipment health monitoring, oil filter analysis was conducted. In this research, analytical ferrography tests were...
A new desalination system using a combination of heat pipe, evacuated tube and parabolic through collector
, Article Energy Conversion and Management ; Volume 99 , July , 2015 , Pages 141-150 ; 01968904 (ISSN) ; Mamouri, S. J ; Shafii, M. B ; Hakim Sima, A ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
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...
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) ; 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,...