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moghaddas--mohsen
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Simulation of Oil Spill in Harbors, Case Study: Rajaee Port
, M.Sc. Thesis Sharif University of Technology ; Raie, Mohammad (Supervisor)
Abstract
Oil spills in marine environments lead to serious environmental disasters and have significant short-term and long-term effects on the aquatic life cycle, the health of people living on the coasts, the region's ecology, and social and economic activities. Shipping and marine transportation are responsible for many oil accidents. For this reason, harbors- as one of the most important marine transportation infrastructures- are always exposed to oil spills which in addition to economic losses, can lead to disruption of ports' performance.To reduce the environmental and economic damages caused by oil spill incidents, it is necessary to prepare the harbors to deal with and clean up oil pollution...
Management of Dams Release According to Agricultural Water Needs with the Aim of Increasing Water Supply to Environmental Needs (A Case Study of Bukan Dam)
, M.Sc. Thesis Sharif University of Technology ; Tajrishi, Mohammad Massoud (Supervisor)
Abstract
The purpose of this research is to first provide an algorithm to reduce the scale of large-scale microwave soil moisture images and then develop an algorithm based on it to manage the release of dams downstream of which are agricultural lands and wetlands. Considering that providing irrigation needs is the purpose of building dams and agriculture is the main consumer of water in dams, optimizing the related releases has a significant effect on reducing water consumption and the possibility of releasing more water for water needs. It has a downstream environment, also agricultural water management has a direct impact on the production of agricultural products and preservation of natural...
Enⅽrypteⅾ Traffiⅽ Anaⅼysis through Expⅼainabⅼe Ⅿaⅽhine Ⅼearning
, M.Sc. Thesis Sharif University of Technology ; Jalili, Rasool (Supervisor)
Abstract
Impressive progress in hardwares and developing encryption algorithms in last two decades are caused increase in using encryption protocols in network communications. In last decade, users use privacy preserving networks like Jap and Tor to protect their privacy. These networks protect users' data from eavesdroppers by using three-layer encryption and intermediate nodes between user and target website. Recent researches show that Deep Neural Networks can predict websites viewed by users with high accuracy. In other words, privacy preserving networks suffer from information leakage. In this research, we introduced some of the most powerful methods in encrypted traffic classification and then...
Synthesis and application of silica aerogel-MWCNT nanocomposites for adsorption of organic pollutants
, Article Scientia Iranica ; Volume 17, Issue 2 F , 2010 , Pages 122-132 ; 10263098 (ISSN) ; Amirkhani, L ; Moghaddas, J. S ; Ahadian, M. M ; Sharif University of Technology
2010
Abstract
Silica aerogel-multi wall carbon nanotube composites were synthesized successfully with a waterglass precursor and an ambient pressure drying method. Pure silica aerogels are so fragile that they cannot be used easily. Carbon nanotubes (MWCNT) were used as reinforcements to strengthen the mechanical properties of pure silica aerogels. Results show that inserting small amounts of MWCNT causes silica aerogels to monolith. By addition of MWCNT, monolith nanocomposites were produced with 800 m2/g surface area and a 140° contact angle. Results show that the silica aerogels and reinforced composites have an excellent adsorption property for the removal of organic pollutants from water. The average...
Evaluation of the Effect of Temperature Gradient on the Dynamic Behavior of Concrete Arch Dams
, M.Sc. Thesis Sharif University of Technology ; Rahim Zadeh Rofooei, Fayyaz (Supervisor)
Abstract
Concrete arch dams, because of their special shape as a 3-D huge shell which is fixed from three sides, are very sensitive to temperature and its variation. Therefore, it is required to include the temperature variations and their related thermal stresses and strains in the safety analysis of dams. In this research, the effect of applying the thermal gradients caused by the most critical thermal conditions, on dynamic behavior of concrete arch dams was studied. For this purpose, first a roughly exact 3-D finite element model of Karoon ІV arch dam was prepared by ANSYS program. Then, the temperature distribution through the dam thickness was determined by Stucky-Derron method and in a more...
Fundamental study of spray and partially premixed combustion of methane/air mixture
, Article ASME 2012 Internal Combustion Engine Division Fall Technical Conference, ICEF 2012 ; 2012 , Pages 417-426 ; 9780791855096 (ISBN) ; Metghalchi, H ; Moghaddas, A ; Hannani, S. K ; Ebrahimi, R ; Sharif University of Technology
2012
Abstract
This study presents fundamentals of spray and partially premixed combustion characteristics of directly injected methane inside a constant volume combustion chamber (CVCC). The constant volume vessel is a cylinder with inside diameter of 135 mm and inside height of 135 mm. Two end of the vessel are equipped with optical windows. A high speed complementary metal oxide semiconductor (CMOS) camera capable of capturing pictures up to 40, 000 frames per second is used to observe flow conditions inside the chamber. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel-air mixture in the vessel, similar to that in a compressed natural gas (CNG) direct...
Sole versus dual-sourcing under order dependent lead-times and prices [electronic resource]
, Article Computers And Operations Research, Published in: Elsevier Journals ; Volume 36, Issue 12, December 2009, Pages 3272–3280 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, we consider a dual-sourcing model with constant demand and stochastic lead times. Two suppliers may be different in terms of purchasing prices and lead-time parameters. The ordering takes place when the inventory level depletes to a reorder level, and the order is split among two suppliers. Unlike previous works in the order splitting literature, the supply lead time between vendor and buyer as well as unit purchasing prices is considered to be order quantity dependent. The proposed model finds out the optimal reorder point, order quantity and splitting proportion, using a solution procedure. Numerical results show that neglecting the relationship between ordering batch size...
Human serum protein adsorption onto synthesis nano-hydroxyapatite
, Article Protein Journal ; Volume 31, Issue 2 , February , 2012 , Pages 150-157 ; 15723887 (ISSN) ; Massah Bidgoli, M ; Behrashi, M ; Mohsen Nia, A ; Sharif University of Technology
2012
Abstract
Adsorption of human serum proteins (Albumin and total protein) onto high purity synthesis nano-hydroxyapatite (HA), Ca 10(PO 4) 6(OH) 2, has been studied in a wide temperature range by UV-visible spectrophotometer. Adsorption isotherm is basically important to describe how solutes interact with adsorbent, andiscriticalinoptimizing the use of adsorbent. Inthe present study, the experimental results werefitted tothe Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) models to obtain the characteristic parameters of each model and square of the correlation coefficients (R 2). According to the results, the DR isotherm model had the best agreement with the experimental data. The effect of...
Flower-like boehmite nanostructure formation in two-steps
, Article Journal of Coordination Chemistry ; Volume 67, Issue 3 , 1 February , 2014 , Pages 555-562 ; ISSN: 00958972 ; Zanganeh, S ; Rajabi, A ; Allahkarami, M ; Rahbari Ghahnavyeh, R ; Moghaddas, A ; Aieneravaie, M ; Asadizanjani, N ; Sadrnezhaad, S. K ; Sharif University of Technology
2014
Abstract
Reaction between AlCl3 and TEA (triethanolamine) gave Al(OH)3 colloidal nanocrystals that were precursors to nucleation and growth of boehmite under hydrothermal conditions. Transition electron microscopic (TEM) observations revealed that flower-like nanostructures were produced through a binary self-assembly system. In the first stage, nanostrips organize themselves to form a bundle, because of NH4 + and TEA. In the second stage, the bundles form flower-like nanostructures due to the interaction of nitrate with TEA. The size of the nanopetals (length 100-200 nm; width 100-150 nm; and thickness 20-70 nm) was measured through TEM. X-ray diffraction and Brunauer-Emmett-Teller (BET-N2) results...
Effective Permeability of Isotropic Overlapping Sandbodies in 2D Using Percolation Theory
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor)
Abstract
Permeability is an essential parameter used for reservoir evaluation, simulation and management to optimize oil recovery. The conventional approach to estimate reservoir connectivity, conductivity, sweep efficiency and other critical information for decision-making is to build detailed geological models, which are then upscaled to a coarser grid where flow simulations are run. However, this takes many hours to be carried out even for a single realization practically. In practice, a very small number of realizations are considered and consequently the true uncertainty in the results is very poorly estimated. In this study, a statistical model of isotropic overlying sandbodies is used to...
A Metabonomics Study of Samples of Different Diseases: Investigation of Linear and Non-Linear Model by Nuclear Magnetic Resonance
, Ph.D. Dissertation Sharif University of Technology ; Tafazzoli, Mohsen (Supervisor)
Abstract
Metabonomics is a quantitative measurement of time dependent metabolic interactions for living systems in response to the pathological or genetic variations. NMR spectroscopy has emerged as a key tool for understanding metabolic processes in living systems. In this project, the study of metabolomics was performed as classification and regression on samples of parkinson’s disease, multiple sclerosis disease, celiac disease and crohn’s disease. In classification part, various methods were applied using optimal parameters.classification methods in Parkinson’s disease, multiple sclerosis disease, celiac disease and crohn’s disease were RF, CART, PLS-DA, RF and RF respectively. Based on the...
Determination of Parameters Affecting the Linear Seismic Evaluation of Gravity Dams Using Nonlinear Analysis
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor)
Abstract
Gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape and the mass and strength of the concrete. Because of their critical role in supplying portable and agricultural water and problems which would happen if they broke, it is required to consider their stability and keep them in safe conditions. They should be able to continue their function after a disaster such as earthquake. But most of them are aged dams with some have been built near faults. Indeed, there are some concerns regarding the performance of these dams under the effect of seismic loads. This research deals with performance evaluation of concerete gravity . The...
Numerical Analysis of Soil-Nailed Walls in Seismic Condition
,
M.Sc. Thesis
Sharif University of Technology
;
Haeri, Mohsen
(Supervisor)
Abstract
Soil nailing is an in-situ technique of mechanically stabilizing soil masses which has been used in France, Germany, United states, and recently in Iran. A review of literature shows that Soil-Nailed walls have performed well during strong ground motions in comparison with the gravity retaining structures. After the 1989 Loma Prieta earthquake, minor signs of distress or corresponding deformation were found on the Soil-Nailed walls, indicating excellent performance of such structures during moderate and strong shakings. These observations indicate that Soil-Nailed walls have an inherent satisfactory seismic response. This has been attributed to the intrinsic flexibility of the Soil-Nailed...
Collapsible Behavior of Gorgan Loess Using Odeometer
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
In nature, there are types of soils that when goinging under stress at constant moisture, or increase of moisture at constant stress, or change of both characters, they show a sudden and high level decrease in their volume. These type of soils are named as Collapsible soils. Iran is one of the countries that at some parts of its land collapsible soils are found. In this research by using of laboratory equipments, the volume change behavior of collapsible loess soils of Gorgan plain (North of Iran) is evaluated under increase of water content and inundation stress. In these experiments, the usual odeometer cell has been used for exploring the behaviour of collapsibility and volume change of...
The Effect of Cementation by Lime on Collapsible Soils Behavior Using Suction Controlled Oedometer Device Case Study: Loess of Gorgan
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
Collapsible soils such as loess, which are naturally found unsaturated, are kind of problematic soils that undergo sudden and noticeable decrease in volume under increasing stress at constant moisture, increasing moisture at constant stress, or increase in both of them. This kind of soil can be found in some parts of Iran such as plain of Gorgan. To fulfill the main purpose of this study, evaluating the effect of cementation on collapse behavior of loess of Gorgan, some oedometer tests under controlled matric suction were performed on reconstituted samples without and with lime. The lime was added for stabilizing of the collapsible materials and the amount was chosen to be %3 by weight of...
An Experimental Investigation of Three-Phase Flow of water-Oil-Gas Mixture Through Water-wet Sandstone
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor)
Abstract
Accurate prediction of relative permeability for various reservoir rocks at various saturation conditions has been of concern for a long time in petroleum industry. Relative permeability is known as one of the most significant parameters in simulation of actual multi-phase flow through porous media during life-time of a hydrocarbon reservoir. In addition, it plays important role in oil production and well completion. Direct experimental measurement in order to determine relative permeability of porous rock has long been recorded in petroleum related literature. However, empirical methods for determining relative permeability are becoming more widely used, particularly with the advent of...
Introducing a Set of Material Strain Measures in Non-Linear Kinematics of Micropolar Continuum Mechanics and Determining their Time Rates
, M.Sc. Thesis Sharif University of Technology ; Asghari, Mohsen (Supervisor)
Abstract
The concept of generalized strains is a well-established subject in the classical continuum mechanics. The characteristics and various applications of the generalized strains have been the point of interest of many researchers in the classical continuum mechanics. The aim of this thesis is the introduction of generalized strains in the micropolar theory, as a non-classical continuum theory. A set of generalized strains is suggested for the deformation of macro-elements. Moreover, a set of generalized strains is proposed for the micro-structures. Since the rate of strains possesses a significant importance in the constitutive equations of nonlinear analysis of solids, expressions for the rate...
Evaluation of the Behaviour of Collapsible Soils in Saturated and Unsaturated Oedometer Tests – Case Study of Gorgan Loess
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
Collapsible soils are kinds of problematic soils which are susceptible to large and sudden reduction in volume upon wetting. A manifest kind of these soils is loess; catastrophic settlement of structures which are built upon it has been observed when the soil becomes wet. In this investigation the collapse potential of samples of loess taken from Gorgan, Golestan, Iran, has been studied by using unsaturated odometer tests under controlled matric suction. To this end, two modified odometer apparatus with the capability of controlling the matric suction, have been designed and developed. Undisturbed samples of soil have been tested under K0 condition, while the matric suction, volumetric...
Performance Evaluation of Concrete Gravity Dam Using Crest Displacement by Nonlinear Analysis
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor)
Abstract
Concrete gravity dams are one of the most important infrastructures therefore their performance under seismic load is an important issue of concern for dam owners. It is necessary that these infrastructures to be able to continue their function after a disaster such as earthquake, as any damage can cause huge cost. For analysis of dams linear and nonlinear analyses are used. Because even operating loads will create cracks in the body of the dam, dam behavior can not always be considered linear. It is remarkable that these surface cracks can join together under seismic loads and this question the safety of dams. It is important to note that nonlinear analysis of concrete gravity dams is...