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Light Duty Vehicles' Emission Reduction Potentials in Megacities
Using New Powertrain Technologies (Case Study: Tehran)
,
M.Sc. Thesis
Sharif University of Technology
;
Erhami, M. (Mohammad)
(Supervisor)
;
Pourzahedi, H. (Hossein)
(Supervisor)
Abstract
Tehran is one of the most polluted megacities in the world, and based on different studies, vehicular sources are responsible for most of the criteria pollutant emissions in this city. The number of vehicles on the streets has been increased drastically leading to growing amount of emission and this trend is continuing. In order to reduce the amount of vehicular emission, it is vital to investigate the factors affecting vehicles emission in this city. This could help to find efficient solutions to improve the situation. Hence, a low-cost methodology to estimate the vehicular emissions is developed. In this...
Proposed Method for Selecting the Most Suitable Contractor Using Risk Analysis
, M.Sc. Thesis Sharif University of Technology ; Mortaheb, Momamad Mehdi (Supervisor)
Abstract
At present, with some exceptions, the contracts are awarded based on the least proposed price. The records show that this method has not been successful especially for the infrastructure projects. In other words the projects awarded this way have been completed with time and cost overruns. Most of the times, such projects have not satisfied the stakeholders' expectations or have had problems during operation phase. The goal of this research is to suggest a method for selecting the most suitable contractor, considering the proposed price as well as incorporating the delay and other risks based on Contractors' actual past performance in the completed projects. Before selecting the Contractor,...
Fabrication of Al Based Nanocomposite with Al2O3 and Al3Ti Reinforcements by Mechanical Milling and Press and Sintering (In situ method) and Investigation of Its Wear Behavior
, M.Sc. Thesis Sharif University of Technology ; Seyed Reihani, M (Supervisor)
Abstract
In this study, Aluminium based nanocomposite with Al3Ti and Al2O3 nanoparticles have been elaborated by mechanical alloying. For this purpose, Al and TiO2 powders have been blended with weight ratios of 10, 20 and 30 percents and were milled using a planetary mill. Morphological variations in different timing periods of mechanical milling process was investigated by Scaning Electron Microscopy (SEM) and The optimal times for alloying were determined for each combination. The pure Aluminium and the powder with 10, 20 and 30%wt reinforcement had coax morphology after respectively for 44, 30, 24 and 14 hours. after studing phase transformations by XRD analysis, the final powders were cold...
, M.Sc. Thesis Sharif University of Technology ; Golshani, M (Supervisor)
Abstract
Most of local thinkers ,who were influenced by Western philosophers of science, and have spoken about religious knowledge, have selected experimental science as standard science and Have tried to find a way trough cultural and other non-scientific channels of science to influence the field of human knowledge by religious teaching's .This expert's are generally opposed to positivist’s models of science, but because of the nature of the Western atmosphere that they breathe, consider the experimental science as the main model of knowledge and the experience as the main method of Acquisition of knowledge. Paya is also one of this thinkers who is influenced by Karl Popper's ideas about the...
Jahn-Teller Effect in Diamond Vacancy Under Stress
, M.Sc. Thesis Sharif University of Technology ; Vesaghi, M. A (Supervisor) ; Babamoradi, M (Co-Advisor)
Abstract
Electron states of diamond vacancy under stress were studied theoretically. The generalized Hubbard model is used to calculate the electrons energy levels. The results shows that the degeneracy of some levels (T, with triple space degeneracy) reduced to levels with lower degeneracy (E, with double space degeneracy and A, without degeneracy). Besides this spiting of degeneracy the energy of all states changed and therefore the transition energy between these states changed too. Jahn-Teller effect was observed
Energy Optimization of an Arm with Seven Degrees of Freedom Using Imperialistic Competitive Algorithm (ICA) and Designing an Artificial Neural Network
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, M.T (Supervisor) ; Asghari, M (Supervisor)
Abstract
In recent years, great attention has been devoted to the design of artificial arms. The most crucial problem in such a design is the trajectory of movement. In this paper, a seven degree of freedom arm is modeled and simulated. Also, the optimization method named “Imperialistic Competitive Algorithm” has been modified and better performance of the new version is presented. Energy optimization is performed based on trajectory of the arm with angular velocity, angular acceleration and joint angles using modified imperialistic competitive algorithm (ICA). Considering ICA as a fast optimization algorithm, it would be reasonable to use this algorithm for robotic purposes for online answering. The...
Sustainable Analysis of Unions Uses Axiomatic Design Theory with Focus on European Union
, M.Sc. Thesis Sharif University of Technology ; Malaek, S. M (Supervisor)
Abstract
In this project, we examine the stability or sustainability issue in unions, in other words we want to know whether integration in European Union is stable? Countries have positive attitude toward unions and being member in unions is at special priorities. The main reason for countires is improve economy and national Security.
The main question in this research is modeling European Union with Axiomatic Design Theory and analysis of sustainability based on this theory. This study has attempted to push Axiomatic Design Theroy in the new field of Systems Engineering and also it gives a new and differnet approach to stability.
The main question in this research is modeling European Union with Axiomatic Design Theory and analysis of sustainability based on this theory. This study has attempted to push Axiomatic Design Theroy in the new field of Systems Engineering and also it gives a new and differnet approach to stability.
Modeling and Analysis of the Powder Deposition Mechanisms of Selective Laser Sintering Process
, M.Sc. Thesis Sharif University of Technology ; Movahedi, Mohamad Reza (Supervisor)
Abstract
Selective laser sintering is a technique which uses a laser as the power source to sintering some selected points at a bed of powder in order to create a solid structure. In this research the SLS mechanisms of powder deposition is simulated and surface smoothness and layer density created by each mechanism is computed. For this purpose roller, blade and hopper mechanisms are simulated. For this simulation, polyamide 12 (PA2200) which is a common material is used. In this simulation at first powder specifications are extracted according to the references and for particle shape instead of using the spherical particle shape we use a certain shape that is more close to reality which created by...
Real-Time Fusion of Asynchronous Data in Distributed Sensor Networks
,
Ph.D. Dissertation
Sharif University of Technology
;
Hemmatyar, A. M. Afshin
(Supervisor)
Abstract
Real-time asynchronous data fusion for high-speed phenomena is an important and challenging task in the sensor networks. Examples of data fusion applications in sensor networks are: managing the traffic of maneuvering airplanes and ground vehicles in airside areas of an airport, traffic management in streets and roads, Driver Assistance Systems, guidance of antiaircraft and antimissile missiles. In all the data fusion applications the estimation of the required variables is necessary.
In this research two methods are introduced for real-time asynchronous data fusion, especially for track-to-track fusion of high-speed phenomena in sensor networks. The effectiveness and usability of these...
In this research two methods are introduced for real-time asynchronous data fusion, especially for track-to-track fusion of high-speed phenomena in sensor networks. The effectiveness and usability of these...
Nonlinear seismic response of concrete gravity dams using damage mechanics including dam-reservoir interaction
, Article Proceedings of the 4th International Conference on Dam Engineering - New Developments in Dam Engineering, Nanjing, 18 October 2004 through 20 October 2004 ; 2004 , Pages 635-642 ; 0415362407 (ISBN); 9780415362405 (ISBN) ; Ghaemian, M ; Sharif University of Technology
shers
2004
Abstract
A local anisotropic damage mechanics model based on energy equivalence was used for evaluating the nonlinear static and dynamic response of concrete gravity dams. The cracks within the elements was formulated as coaxial rotating cracks and the effect of hydrodynamic pressure was included using the staggered displacement method. The features of strain rate effects; strain softening and closing/reopening of cracks were included in the model. The mesh objectivity of the nonlinear model was satisfied by the fracture energy conservation technique. The Pine Flat dam was chosen to investigate the performance of the proposed algorithms. It was found that the resulted crack profiles when including...
Unsupervised cross-subject BCI learning and classification using riemannian geometry
, Article 24th European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning, ESANN 2016, 27 April 2016 through 29 April 2016 ; 2016 , Pages 307-312 ; 9782875870278 (ISBN) ; Shamsollahi, M. B ; Jutten, C ; Congedo, M ; Sharif University of Technology
i6doc.com publication
2016
Abstract
The inter-subject variability poses a challenge in cross-subject Brain-Computer Interface learning and classification. As a matter of fact, in cross-subject learning not all available subjects may improve the performance on a test subject. In order to address this problem we propose a subject selection algorithm and we investigate the use of this algorithm in the Riemannian geometry classification framework. We demonstrate that this new approach can significantly improve cross-subject learning without the need of any labeled data from test subjects
Investigation of cervical spine curvature in females with postural neck pain
, Article Journal of Zanjan University of Medical Sciences and Health Services ; Volume 25, Issue 110 , 2017 , Pages 110-119 ; 16069366 (ISSN) ; Maroufi, N ; Ahmadi, A ; Behtash, H ; Hazhir Sahneh, S ; Parnianpour, M ; Sharif University of Technology
Zanjan University of Medical Sciences and Health Services
2017
Abstract
Background and Objective: Changes in the cervical spine curvature leads to increased shear force and compression stress on cervical spine and axial loading in different cervical segments. The objective of this study was to compare the general and segmental curvature in the upper and lower cervical spine of women with postural neck pain and Forward Head Posture (FHP), women without neck pain but with FHP and healthy women. Material and Methods: 45 women were divided into three groups: 15 women with postural neck pain and FHP, 15 women without neck pain but with FHP and 15 healthy women. Photography was used to assess neck posture while cervical spine curvature was measured using fluoroscopy...
Evaluation of the effects of fullerene c60 nanoparticles on oxidative stress parameters in normal rats liver and brain
, Article Journal of Advances in Medical and Biomedical Research ; Volume 27, Issue 124 , 2019 , Pages 8-15 ; 26766264 (ISSN) ; Bahrami, F ; Bahri, Z ; Ghanbari, B ; Elahi, S. A ; Mohammadi, M. T ; Sharif University of Technology
Zanjan University of Medical Sciences and Health Services
2019
Abstract
Background & Objective: The potent antioxidant property of fullerene C60 nanoparticles and their derivatives has been demonstrated in a wide range of in vitro and in vivo studies. Hence, we examined the effects of fullerene C60 on the oxidative stress parameters in brain and liver of the rats in normal situation. Materials & Methods: The study was performed in two groups of Wistar rats (each group, n = 6); normal and fullerene-treated normal animals. Treated rats received fullerene via oral gavage at dose of 1 mg/kg/day for 60 days. At termination of the study, the oxidative stress parameters were determined in brain and liver tissues, including the contents of glutathione (GSH) and...
Experimental investigation of dual-purpose solar collector using with rectangular channels
, Article Journal of Thermal Engineering ; Volume 3, Issue 1 , 2017 , Pages 1052-1059 ; 21487847 (ISSN) ; Saidi, M. H ; Sharif University of Technology
Yildiz Technical University
2017
Abstract
Solar heat energy, one of the typical renewable energy absorbs radiation energy from the sun and converts it into heat energy. Since it is sustainable and eco-friendly, it can be a good alternative to solve the problem of the depletion of fossil fuels. But it has low density. So, solar collector is very important to use more efficiently. There are some possible approaches to scaling-up the effectiveness of a collector by re-thinking of using the collector as a heat exchanger. In the design of dual-purpose collector with rectangular fin (DPCRF), can be used for heating air and water simultaneously using incident solar radiation resulting in optimum usage of energy and space
Thermoeconomic analysis and multi-objective optimization of a novel trigeneration system consisting of kalina and humidificationdehumidification desalination cycles
, Article Journal of Thermal Engineering ; Volume 8, Issue 1 , 2022 , Pages 52-66 ; 21487847 (ISSN) ; Faegh, M ; Fakhari, I ; Ahmadi, P ; Faegh, E ; Rosen, M. A ; Sharif University of Technology
Yildiz Technical University
2022
Abstract
Low-temperature geothermal heat sources have the highest share of geothermal energy in the world. Utilization of these heat sources for energy and freshwater generation can play an important role in meeting energy and freshwater demands. To do so, this study aims to propose a novel trigeneration cycle powered by low-temperature geothermal sources. The proposed system, which is an integration of Kalina and humidification-dehumidification (HDH) cycles, is used for the generation of electricity, heating, and freshwater. For the Kalina cycle, an evaporative condenser is used. It also acts as a humidifier and heater of the humidification-dehumidification desalination cycle, resulting in a...
Adaptive sparse representation for MRI noise removal
, Article Biomedical Engineering - Applications, Basis and Communications ; Volume 24, Issue 5 , October , 2012 , Pages 383-394 ; 10162372 (ISSN) ; Fatemizadeh, E ; Behnam, H ; Sharif University of Technology
World Scientific
2012
Abstract
Sparse representation is a powerful tool for image processing, including noise removal. It is an effective method for Gaussian noise removal by taking advantage of a fixed and learned dictionary. In this study, the variable distribution of Rician noise is reduced in magnetic resonance (MR) images by sparse representation based on reconstruction error sets. Standard deviation of Gaussian noise is used to find these errors locally. The proposed method represents two formulas for local error calculation using standard deviation of noise. The acquired results from the real and simulated images are comparable, and in some cases, better than the best Rician noise removal method due to the...
Dynamics and stability analysis of rotating cylindrical shells in annular fluid medium
, Article International Journal of Structural Stability and Dynamics ; Volume 20, Issue 8 , 2020 ; Firouz Abadi, R. D ; Rahmanian, M ; Sharif University of Technology
World Scientific
2020
Abstract
Stability and dynamics of rotating coaxial cylindrical shells conveying incompressible and inviscid fluid are investigated. The interior shell is assumed to be flexible while the exterior cylinder is rigid. Using Sander's-Koiter theory assumptions and following Hamilton's principle, governing equations of motion are determined in their integral form. Employing the extended Galerkin method of solution, the integral equations of motion are projected to their equivalent system of algebraic equations. Fluid equations are fundamentally based on the linearized inviscid Navier-Stokes equations. Impermeability condition on the fluid and structure interface as well as the zero radial velocity...
Three-dimensional spread analysis of a Dengue disease model with numerical season control
, Article International Journal of Biomathematics ; Volume 14, Issue 8 , 2021 ; 17935245 (ISSN) ; Hesaaraki, M ; Sharif University of Technology
World Scientific
2021
Abstract
Dengue is among the most important infectious diseases in the world. The main contribution of our paper is to present a mixed system of partial and ordinary differential equations. This combined model is a generalization of the two presented mathematical models (A. L. de Araujo, J. L. Boldrini and B. M. Calsavara, An analysis of a mathematical model describing the geographic spread of dengue disease, J. Math. Anal. Appl. 444 (2016) 298-325) and (L. Cai, X. Li, N. Tuncer, M. Martcheva and A. A. Lashari, Optimal control of a malaria model with asymptomatic class and superinfection, Math. Biosci. 288 (2017) 94-108), describing the geographic spread of dengue disease. Our model has the ability...
Characterization of magnetized CNT-based hybrid nanofluid subjected to convective phenomenon
, Article International Journal of Modern Physics B ; Volume 35, Issue 28 , 2021 ; 02179792 (ISSN) ; Khan, W. A ; Aqsa ; Waqas, M ; Abbas, S. Z ; Malik, M. Y ; Alqahtani, A. S ; Sharif University of Technology
World Scientific
2021
Abstract
Hybrid nanofluid gains attention of scientists due to its dynamic properties in various fields, and thus, hybrid nanofluids can be taken as an innovative form of nanofluids. Even though analysts acquire tremendous results in the field of hybrid nanofluids but yet no study has been carried out to predict magnetohydrodynamic effects in such fluid models. In this present analysis, influence of MHD has been investigated for the micro hybrid nanofluid over a stretched surface under convective conditions. Combine boundary layer equations for the flow have been altered into a suitable form via boundary layer approximations. Further, complete nonlinear system of equations has been numerically solved...
Analytical solution of nonlinear differential equations two oscillators mechanism using Akbari-Ganji method
, Article Modern Physics Letters B ; Volume 35, Issue 31 , 2021 ; 02179849 (ISSN) ; Hosseinzadeh, K ; Rahai, M ; Ganji, D. D ; Sharif University of Technology
World Scientific
2021
Abstract
In the last decade, many potent analytical methods have been utilized to find the approximate solution of nonlinear differential equations. Some of these methods are energy balance method (EBM), homotopy perturbation method (HPM), variational iteration method (VIM), amplitude frequency formulation (AFF), and max-min approach (MMA). Besides the methods mentioned above, the Akbari-Ganji method (AGM) is a highly efficient analytical method to solve a wide range of nonlinear equations, including heat transfer, mass transfer, and vibration problems. In this study, it was constructed the approximate analytic solution for movement of two mechanical oscillators by employing the AGM. In the derived...