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Water allocation using game theory under climate change impact (Case study: Zarinehrood)
, Article Journal of Water and Climate Change ; Volume 12, Issue 3 , 2021 , Pages 759-771 ; 20402244 (ISSN) ; Abrishamchi, A ; Sharif University of Technology
IWA Publishing
2021
Abstract
The combined effects of climate change and growing water demand due to population growth, industrial and agricultural developments cause an increase in water scarcity and the subsequent environmental crisis in river basins, which results in conflicts over the property rights and allocation agreements. Thus, an integrated, sustainable and efficient water allocation considering changes in water resources due to climate change and change of users’ demands is necessary. In this study, the drainage basin of Zarinehrood was chosen to evaluate the function of selective methods. Assessing climate change impact scenarios of the Fifth IPCC reports, e.g., RCP2.6, RCP4.5, RCP6.0 and RCP8.5, have been...
General Review of the Gamma Irradiators for the Purpose of Desing Improvement of Multipurpose Systems
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor)
Abstract
Ionizing radiation can modify physical, chemical and biological properties of the irradiated materials. At present, the principal industrial applications of radiation are sterilization of health care products including pharmaceuticals, irradiation of food and agriculture products and materials modification. In the above application the wide range of the required doses together with different product densities require spatial mechanical design of the irradiators to be able to properly handle the specified tasks. In the multipurpose irradiators the design of system and positioning of the source must be done in such a way that a nearly optimum dose distaition in the product boxes in...
An analytical investigation of elastic-plastic deformation of FGM hollow rotors under a high centrifugal effect
, Article International Journal of Mechanical and Materials Engineering ; Volume 14, Issue 1 , 2019 ; 18230334 (ISSN) ; Aghajani, S ; Hemati, M ; Sharif University of Technology
Springer
2019
Abstract
Functionally graded material shafts are the main part of many modern rotary machines such as turbines and electric motors. The purpose of this study is to present an analytical solution of the elastic-plastic deformation of functionally graded material hollow rotor under a high centrifugal effect and finally determine the maximum allowed angular velocity of a hollow functionally graded material rotating shaft. Introducing non-dimensional parameters, the equilibrium equation has been analytically solved. The results for variable material properties are compared with the homogeneous rotor and the case in which Young’s modulus is the only variable while density and yield stress are considered...
Optimal Design of Tolerances in the Non-rigid Assemblies under the Thermal Impact
, M.Sc. Thesis Sharif University of Technology ; Khodaygan, Saeed (Supervisor)
Abstract
Tolerance allocation in the recent mechanical assembly is significant because it straightly affects product performance and cost. Loose tolerances may cause the quality defect while tight tolerances can increase the cost. Thermal effects and the temperature gradients are one of the factors that caused changes in the size and geometry of the components during the performance of mechanical assemblies. This thesis proposes a new approach for tolerance design considering the thermal effects, to achieve lower manufacturing cost and good product quality. Finite element analysis is used to determine the deformation of components in an assembly. The neural network is trained using experimental...
History Modeling in Conversational Question Answering
, M.Sc. Thesis Sharif University of Technology ; Beigy, Hamid (Supervisor)
Abstract
In this thesis, we propose a method for long document modeling to address the issue of handling lengthy documents. The results indicate that our method successfully improves the problem of independently modeling chunks that arise from long documents. Additionally, we present consistent training using history augmentation to enhance the representation of questions with a long history. Our experiments demonstrate that this proposed method increases the performance of the baseline model, particularly for questions with a long history. The long document modeling approach improves the baseline's performance by 2.1% based on the F1 criteria. Furthermore, the consistent training using history...
A bi-objective aggregate production planning problem with learning effect and machine deterioration: modeling and solution
, Article Computers and Operations Research ; Volume 91 , March , 2018 , Pages 21-36 ; 03050548 (ISSN) ; Akhavan Niaki, S. T ; Hemati, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The learning effects of the workers and machine deterioration in an aggregate production planning (APP) problem have not been taken into account in the literature yet. These factors affect the performance of any real-world production system and require attention. In this paper, a bi-objective optimization model is developed for an APP problem with labor learning effect and machine deterioration. The first objective of this model maximizes the profit by improving learning and reducing the failure cost of the system. The second objective function minimizes the costs associated with repairs and deterioration, which depend on the failure rate of the machines in the production periods. The aim of...
Conflict Resolution of water resources Allocation Using Game Theory under Climate Change Impact (Case Study: Zarinehrood basin)
, M.Sc. Thesis Sharif University of Technology ; Abrishamchi, Ahmad (Supervisor) ; Tajrishi, Masoud (Co-Supervisor)
Abstract
Increasing water consumption via competitive demands has resulted in serious water conflicts and the subsequent environmental crisis in river basins. The combined effects of climate change on river flow and growing water demand due to population growth, industrial and agricultural developments cause an increase of water scarcity in many basins. This is one of the drivers of both noncompliance with water allocation agreements and conflicts over the property rights to river water. Conflicts often arise when different water users compete for a limited water supply. Thus an integrated, sustainable, efficient and fair water allocation considering changes in water resources due to climate change...
Surfactant effects on the particle size, zeta potential, and stability of starch nanoparticles and their use in a pH-responsive manner
, Article Cellulose ; Volume 24, Issue 10 , 2017 , Pages 4217-4234 ; 09690239 (ISSN) ; Kashanian, S ; Hemati Azandaryani, A ; Omidfar, K ; Bazyar, E ; Sharif University of Technology
2017
Abstract
Storage conditions seem to be important in the long-term stability of nanoparticles (NPs). This work studies the effects of surfactants and storage container on particle size distribution and zeta potential during long-term storage of acid hydrolyzed potato starch NPs. The NPs were prepared from potato starch using acid hydrolysis and high-intensity ultrasonication. During the ultrasonic treatment, the surfactants were added dropwise to the solutions to reduce the size and stabilize the formed NPs. Particle size distribution, zeta potential, and FE-SEM were used to characterize the ensuing NPs. Additionally, a 5-month stability study was performed to evaluate the maintenance of potato starch...
Performance analysis of the outer rotor variable reluctance resolver
, Article 2023 3rd International Conference on Electrical Machines and Drives, ICEMD 2023 ; 2023 ; 979-835039374-3 (ISBN) ; Hajmohammadi, S ; Nasiri Gheidari, Z ; Hemati, D ; Oraee, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
Position sensors are essential in the control of moving systems. Variable Reluctance (VR) resolvers are used as position sensors in the control of permanent magnet motors due to their simple and robust structure. VR resolvers can be built in outer/inner stator configuration. Although most of the commercial VR resolvers have outer stator /inner rotor configuration, the manufacturing process of the inner stator resolver is much simpler than that of outer stator ones. However, design considerations of inner stator/outer rotor configurations are not well established. Therefore, in this paper the influence of different number of stator slots, pole number of windings, and number of rotor saliency...
Improve the Structure of Membrane Bioreactor to Reduce Fouling for Industrial Waste Water Purification
, M.Sc. Thesis Sharif University of Technology ; Seifkordi, Ali Akbar (Supervisor) ; Hemati, Mahmood (Co-Advisor)
Abstract
In the presence project by using of hydrophilic polymer, Cellulose acetate (CA), we tried to modify the membrane made of Polyvinylidine fluoride (PVDF). The membranes were made by phase inversion method. In five levels, at least 10% and at most 30%, CA was added to casting solution. The hydrophilicity of membranes’ surface and pore size was increased. The permeation of the neat membrane of PVDF was less than 10 , on the other hand the permeation of the membranes, which were made by adding CA, was increased up to 500 . The increment of CA more than 20% reduced the porosity of membrane. In the next step to reduce the irreversibility fouling tried to reduce the pore size by adding some...
Construction of a New Membrane Bioreactor for Industrial Wastewater Treatment
, M.Sc. Thesis Sharif University of Technology ; Seifkordi, Ali Akbar (Supervisor) ; Hemati, Mohmoud (Co-Advisor) ; Rekabdar, Fatemeh (Co-Advisor)
Abstract
In recent years membrane bioreactors (MBR) were widely used as an advanced process for industrial wastewater treatment. But fouling issue causes some restrictions in these systems. So for fouling reduction many researches were done.In this study for fouling improvement, blending of hydrophilic polymer (PAN) with main polymer PVDF was used. Blending membrane in phase inversion process with DMAC as solvent and water as non-solvent was made. For pore-forming in membranes, PVP as hydrophilic additive with three different composition was added and then for more enhancement of antifouling property of membrane, TiO2 nanoparticles with four different composition were added to polymeric...
Synthesis of Mg / MgO - Mg2Cu by in-situ Reaction Method and Investigation on Structure and Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Salahi, Esmaeil (Supervisor) ; Pour Azarang, Kazem (Co-Advisor)
Abstract
In this project formation of MgO & Mg2Cu reinforcement particle in Magnesium matrix was investigated. Firstly Mg & CuO powders mixture in different weight percentage (4, 8%wt CuO) in 20:1 and 30:1 BPR were milled. Finally, according to XRD result 30:1 BPR was selected for milling. Variations in powders morphology, particles size, crystallite size, lattice strain and phase transformation were investigated by X-ray diffraction, scanning electron microscopy and laser particle size analyzer in different milling time. Result showed that during reaction between Mg and CuO, MgO & Mg2Cu reinforcement particles were formed in matrix. Matrix crystallite size was determined about 35-40 nm. Mg-6.3%wt Cu...
Sutnlp at semeval-2023 task 10: rlat-transformer for explainable online sexism detection
, Article 17th International Workshop on Semantic Evaluation, SemEval 2023 - Proceedings of the Workshop ; 2023 , Pages 347-356 ; 978-195942999-9 (ISBN) ; Alavian, H ; Beigy, H ; Sameti, H ; Ojha A. K ; Dogruoz A. S ; Da San Martino G ; Madabushi H. T ; Kumar R ; Sartori E ; Sharif University of Technology
Association for Computational Linguistics
2023
Abstract
There is no simple definition of sexism, but it can be described as prejudice, stereotyping, or discrimination, especially against women, based on their gender. In online interactions, sexism is relatively rare but still harmful. One out of ten American adults says that they have been harassed because of their gender and have been the target of sexism, so sexism is a growing issue. The Explainable Detection of Online Sexism shared task in SemEval-2023 aims at building sexism detection systems for the English language. In order to address the problem, we use large language models such as RoBERTa and DeBERTa. In addition, we present a novel method called Random Layer Adversarial Training...