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Multi-Objective Dual-use Airport (Civil/Military)Gate Assignment Problem
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor) ; Fathi, Mohsen (Supervisor)
Abstract
Existing trend in the world transportation industries have created number of bottlenecks that in some cases have lead to substantial delays. Among which the most important one is the airport and how it is managed. This work investigates a new approach to increase an airport capacity in a procedural manner and without having to invest heavily on the infra-structure. The main objective of the work is to propose a sustainable approach to make use of military airports as a civilian one. In fact, we seek to define a model or process for the two major stakeholders (military airlines, civilian airlines) that guarantees a durable cooperation.Here, we have effectively made use of computer program...
Investigation on Phased Arrays with Irregular Overlapped Subarrays
,
M.Sc. Thesis
Sharif University of Technology
;
Nayebi
(Supervisor)
Abstract
In this thesis, we would consentraite in the topic of irregular overlapped subarrays. In general, it would be a combination of topics overlapped and irregual arrays. In phased array topics, one of the important issues is cost. Main cost of array is consist of its phase shifter cost at all. Duo to the cost of phase shofters, overlapped subarray structure might be used. Philosophy of using overlapped subarrays returned to similar phase required for elements adjust together. But this emphasis is true just in limited field of view fields. But grating lobes could be seen even without beam steering. For solving grating lobes problem, overlapped structured has been presented. In overlapped...
Matrix approach to irregular overlapped subarrays
, Article 2016 CIE International Conference on Radar, RADAR 2016, 10 October 2016 through 13 October 2016 ; 2017 ; 9781509048281 (ISBN) ; Nayebi, M. M ; Sharif University of Technology
2017
Abstract
Overlapped subarrays have cost benefits compared with non-overlapped subarrays. The main cost of phased array radars are for phase shifter or true time delay modules in the case of wide band radars. In overlapped approach, each phase shifter (or time delay module) might have more than one output and it would reduce costs. Although, overlapped subarrays could fit in reduced space too. A main problem in overlapped subarrays is their limited field of view properties. On the other side, in irregular subarrays, the LFOV (Limited Field Of View) problem solved. So in this article the advantages of mentioned two fields cumulated. In the first part, a review of subarray structure presented. Then...
Matrix approach to irregular overlapped subarrays
, Article Proceedings International Radar Symposium, 28 June 2017 through 30 June 2017 ; 2017 ; 21555753 (ISSN) ; 9783736993433 (ISBN) ; Nayebi, M. M ; Sharif University of Technology
2017
Abstract
Overlapped subarrays have cost benefits compare to non-overlapped subarrays. The main cost of phased array radars are for phase shifter or true time delay modules in the case of wide band radars. In overlapped approach, each phase shifter (or time delay module) might have more than one output and it would reduce costs. Although, overlapped subarrays could fit in reduced space too. A main problem in overlapped subarrays is their limited field of view properties. On the other side, in irregular subarrays, the LFOV (Limited Field Of View) problem solved. So in this article the advantages of mentioned two fields cumulated. In the first part, a review of subarray structure presented. Then matrix...
Design and Fabrication of Weigh in Motion System for Railway Vehicles
, M.Sc. Thesis Sharif University of Technology ; Saadat Foumani, Mahmud (Supervisor)
Abstract
Railroads should be well maintained for safe and efficient operation. The most important reason for the failure of railways is overload and asymmetric load on them. Also, the proper interval for repairs should be adjusted to fit the load crossed over. In order to carry out all these tasks, a constant observation of the weight on the rails must take place. Current dynamic weighing systems are costly. In addition, the installation of these systems is time-consuming and causes permanent damage to the rails. On the other hand, some of the cheaper models of weighing systems require full stop and static weighing, which practically does not work at all, especially on busy rails due to delays. The...
Analysis and Performance Improvement of Synthetic Impulse and Aperture Radar
, Ph.D. Dissertation Sharif University of Technology ; Nayebi, Mohammad Mahdi (Supervisor) ; Karbasi, Mohammad (Co-Supervisor)
Abstract
Multi-Input Multi-Output (MIMO) systems are a type of radar that utilizes multiple transmitters and multiple receivers along with various signaling techniques to optimize several aspects compared to conventional radars. The subject of this doctoral dissertation focuses on a specific type of MIMO radar known as Synthetic Impulse and Aperture Radar (SIAR). In this context, one of these MIMO radar models, recognized as SIAR, has unique characteristics that we will explore here. Initially, the sources will be examined, and the problem formulation of this type of radar will be analyzed. Subsequently, there will be an emphasis on target detection and separation in low-altitude scenarios. Various...
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...
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...
Physical Modeling of Effect of Liquefaction-Induced Lateral Spreading on Single Piles
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
Pile foundations suffered severe damages during the past earthquakes in all around the world. These damages were more severe in laterally spreading grounds and they mostly have been observed in gently sloping grounds and coastal areas. In these cases, Pile foundations not only are subjected to structures inertial loads and kinematic loads of liquefied soil but also lateral spreading intensifies damages. Thus, in the recent decade, several researches have been conducted to investigate the behavior of pile foundations in liquefiable and laterally spreading grounds, however, some uncertainties still remain in modeling of soil-pile interaction. In this study, the effects of liquefaction- induced...