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Evaluation of the effect of organic pollutants exposure on the antioxidant activity, total phenolic and total flavonoid content of lettuce (Lactuca sativa L.) using UV–Vis spectrophotometry and chemometrics
, Article Microchemical Journal ; Volume 170 , 2021 ; 0026265X (ISSN) ; Parastar, H ; Sharif University of Technology
Elsevier Inc
2021
Abstract
In the present contribution, the effects of different contaminants of emerging concerns (CECs), including parabens, drugs, and polycyclic aromatic hydrocarbons (PAHs) on antioxidant activity of Lactuca sativa L. in different concentration levels (10–500 µg L−1) were evaluated using ultraviolet–visible (UV–Vis) spectrophotometry combined with chemometric techniques. The extracts of lettuce samples were investigated for the antioxidant activity (AA), total phenolic content (TPC), and total flavonoid content (TFC) after 39 days of planting and 14 days of exposure. Then, the spectroscopic data were arranged in two different data matrices, including (i) the control lettuce samples and PAHs...
Resolution improvement of hall effect gear tooth magnetic encoder
, Article 2023 3rd International Conference on Electrical Machines and Drives, ICEMD 2023 ; 2023 ; 979-835039374-3 (ISBN) ; Nasiri Gheidari, Z ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
Magnetic encoders as position sensors are widely used in industrial applications. They have numerous benefits, including resilience, cheap maintenance costs, minimal sensitivity to EMI noise, and a wide temperature range. However, they suffer from relatively low resolution. Therefore, the highest resolution that a magnetic encoder may achieve is estimated in this study. Then, a low-cost output circuit is proposed to increase the resolution of magnetic encoder without changing its primary parameters. The experimental measurements on the porotype of the sensor approve the success of the proposed method. © 2023 IEEE
Effect of Alternative Electromagnetic Vibration on Joining of 2024 Aluminum Alloy
, M.Sc. Thesis Sharif University of Technology ; Ashuri, Hossein (Supervisor)
Abstract
2024 Aluminum alloy has an abundant application in the aerospace and automobile industries. One of the most important problems of the alloy is hot cracking during the fusion welding process. It is stated that the solidified grains can be refined by a static magnetic field and an alternative electric field applied simultaneously during solidification. To make the alternative electric field, an alternative current was passed through the specimen. In order to prevent hot cracking, electromagnetic vibration was used. Then the effect of intensity of the static magnetic field and alternative electric current on joint was examined. Joining was carried out at electric currents of 40, 60, and 80A and...
Colorful paths in vertex coloring of graphs
, Article Electronic Journal of Combinatorics ; Volume 18, Issue 1 , 2011 , Pages 1-9 ; 10778926 (ISSN) ; Liaghat, V ; Nikzad, A ; Sharif University of Technology
2011
Abstract
A colorful path in a graph G is a path with χ(G) vertices whose colors are different. A v-colorful path is such a path, starting from v. Let G ≠ C7 be a connected graph with maximum degree Δ (G). We show that there exists a (Δ(G)+1)-coloring of G with a v-colorful path for every v ∈ V (G). We also prove that this result is true if one replaces (Δ (G) + 1) colors with 2 χ(G) colors. If χ (G) = ω(G), then the result still holds for χ(G) colors. For every graph G, we show that there exists a χ(G)-coloring of G with a rainbow path of length ⌊ χ(G)/2⌋ starting from each v ∈ V (G)
Mechanism of Al-Si codeposition on In738LC through single-step diffusion process
, Article International Journal of Surface Science and Engineering ; Volume 11, Issue 1 , 2017 , Pages 1-11 ; 1749785X (ISSN) ; Abdi, M ; Rastegari, S ; Sharif University of Technology
2017
Abstract
The out-of-pack cementation method was applied to coat the Nickel-based super alloy IN738LC with Si-modified aluminide. Different mixtures of the pack containing pure Al, Si, alumina powders as an inert filler, and NH4Cl as a halide salt activator were used for co-deposition at 950 and 1,050°C. The results showed although the amount of subhalide vapour pressures of Al and Si were equal at 1,050°C, Al atoms diffused only after Si atoms had been deposited. Before heat treatment, the coating thickness formed by the pack containing 2.3 wt.% Al was 6 μm more than that containing 3.5 wt.% Al. After heat treatment, thickening coatings formed within the pack containing 2.3 wt.% Al was less than that...
Design and Analysis of Magnetic Encondor
, M.Sc. Thesis Sharif University of Technology ; Nasiri Gheidari, Zahra (Supervisor)
Abstract
Measuring the speed and position of the rotating part and using the speed and position information in the closed loop control of electric machines is very important. Various sensors are available for this purpose, including resistive sensors, capacitive sensors, encoders, synchros, resolvers, Halleffect sensors, and etc. Common encoders include optical and magnetic types. There are two main problems in using an encoder as a sensor: determining/maintaining accuracy during change of rotational direction and determining the absolute position. Both of the mentioned challenges have been investigated in the case of optical encoders and some solutions have been provided to overcome them. Although...
Development of a Neuro-muscular Model for Stroke Patient in Reaching Motion and Experimental Evaluation
, M.Sc. Thesis Sharif University of Technology ; Behzadipour, Saeed (Supervisor)
Abstract
Paralysis is one of the most common disabilities resulting from stroke. Usually injury to one hemisphere of the brain affects the opposite side of the body. This one-sided paralysis is called hemiplegia Damage to a lower part of the brain, the cerebellum, can affect the body's ability to coordinate movement, a disability called ataxia, leading to problems with body posture, walking, and balance. Reaching tasks are building blocks of most daily functional movements. The purpose of such a movement is to transfer a specific point of hand (e.g. fingertip) toward a special location in space around. In people with ataxia, trajectories of reaching movements are far different from healthy people in...
Green supply chain network design considering inventory-location-routing problem: A fuzzy solution approach
, Article International Journal of Logistics Systems and Management ; Volume 35, Issue 4 , 2020 , Pages 436-452 ; Ashoftehfard, A ; Mina, H ; Sharif University of Technology
Inderscience Publishers
2020
Abstract
The growing rate of population and technological advancement have led to an increase in natural resource consumption, which has caused irreparable damage to the environment. The implementation of green supply chain management is one of the most effective ways to deal with environmental degradation. Therefore, in this paper, a bi-objective mixed integer linear programming model is developed to design a green supply chain network. In the proposed model, the possibility of customer storage, being faced with shortage, locating of distribution centres, green vehicle routing problem, split delivery, multi-depot vehicle routing problem (VRP), capacitated VRP, and uncertainty in demands will be...
A dynamic decision support system for sustainable supplier selection in circular economy
, Article Sustainable Production and Consumption ; Volume 27 , 2021 , Pages 905-920 ; 23525509 (ISSN) ; Tavana, M ; Mina, H ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Supplier selection is an important and challenging problem in sustainable supply chain management. We propose a dynamic decision support system (DSS) for sustainable supplier selection in circular supply chains. Unlike the linear take-make-waste-dispose production systems, circular supply chains are nonlinear make-waste-recycle production systems with zero-waste vision. The proposed DSS allows users to customize and weight their economic, social, and circular criteria with a fuzzy best-worst method (BWM) and select the most suitable supplier with the fuzzy inference system (FIS). Machine learning is used to maintain and synthesize the criteria scores for the suppliers after each supplier...
A dynamic decision support system for sustainable supplier selection in circular economy
, Article Sustainable Production and Consumption ; Volume 27 , 2021 , Pages 905-920 ; 23525509 (ISSN) ; Tavana, M ; Mina, H ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Supplier selection is an important and challenging problem in sustainable supply chain management. We propose a dynamic decision support system (DSS) for sustainable supplier selection in circular supply chains. Unlike the linear take-make-waste-dispose production systems, circular supply chains are nonlinear make-waste-recycle production systems with zero-waste vision. The proposed DSS allows users to customize and weight their economic, social, and circular criteria with a fuzzy best-worst method (BWM) and select the most suitable supplier with the fuzzy inference system (FIS). Machine learning is used to maintain and synthesize the criteria scores for the suppliers after each supplier...
Reliability enhancement and price reduction of restructured power system with probabilistic day-ahead real time pricing contract
, Article IEEE Power Engineering Society (IEEE/PES); Chinese Society for Electrical Engineering (CSEE) ; 2010 ; 9781424459407 (ISBN) ; Mozafari, B ; Ranjbar, A. M ; Sharif University of Technology
2010
Abstract
Lack of demand response has always been the main reason for price increasing, shortage of production capacity and system risk increasing as the electricity markets have been greatly involved during the past years. In Electricity market, the exchanges are profitable for producers and consumers when both can participate freely. Based on this new environment, we are currently facing with a new concept as demand-side participation or demand response. There are several demand response programs that accurate pricing of each them is the major challenge that retailers and market operators are facing with. In this article the day-ahead real time pricing contract (DA-RTP) based on two different...
Development a planar neuro-musculoskeletal arm model in post-stroke patients
, Article 26th National and 4th International Iranian Conference on Biomedical Engineering, ICBME 2019, 27 November 2019 through 28 November 2019 ; 2019 , Pages 236-241 ; 9781728156637 (ISBN) ; Asghari, M ; Behzadipour, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Computational models of the central nervous system after a stroke helps to reveal the physiological mechanisms that may have strong impacts on the neuro-motor rehabilitation approaches. This paper studies the stroke subject's motor control mechanism in reaching movements by extending the previous study by incorporating the kinematics of motion as well as neural disconnection between the muscles and the CNS to further develop a planar patient specific neuro-musculoskeletal model of arm. The developed model was calibrated to eight post-stroke individuals by altering the Muscle Significance Factors (MFS) using numerical optimization to match the simulated motions with those measured...
A fuzzy solution approach to supplier selection and order allocation in green supply chain considering the location-routing problem
, Article Scientia Iranica ; Volume 28, Issue 1 E , 2021 , Pages 446-464 ; 10263098 (ISSN) ; Haji, A ; Mina, H ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
In the eld of supply chain, selecting a suitable green supplier could signi cantly help us decrease the cost and risks of the operations and increase the quality of green supply. This paper develops an integrated two-stage approach based on Fuzzy Analytic Hierarchy Process (FAHP) and multi-objective mixed-integer linear programming to select suppliers and allocate order in the green supply chain. In the rst stage, suppliers are evaluated using FAHP method and in the second stage, a multi-product multi-period supply chain is developed considering green location-routing problem, discounting, and time window under uncertainty. Then, a fuzzy solution approach is applied to solve the proposed...
Microstructural modification of Al–30Si–5Fe Alloy using a combination of rapid solidification and thixoforming processes
, Article Metallography, Microstructure, and Analysis ; Volume 5, Issue 3 , 2016 , Pages 217-228 ; 21929262 (ISSN) ; Aashuri, H ; Ferasat, K ; Nikzad, S ; Sharif University of Technology
Springer New York LLC
2016
Abstract
It is commonly known that the properties of materials are strongly related to their microstructure. This paper introduces a method that is a combination of rapid solidification (melt spinning) and semisolid forming (thixoforming) processes, which are used to refine the microstructure of “as-cast” Al–30Si–5Fe alloy and improve its mechanical properties. Produced Al–30Si–5Fe ribbons by melt-spinning process, were pulverized and subsequently consolidated at 300 °C in argon atmosphere. Prepared specimens were thixoformed at temperatures ranging from 580 to 700 °C in various holding times. Some samples were also directly thixoformed from as-cast condition. Microstructure of the as-cast, meltspun,...
Mechanical properties of Al–30Si–5Fe alloy using combination of rapid solidification and thixoforming processes
, Article Metallography, Microstructure, and Analysis ; Volume 6, Issue 6 , 2017 , Pages 502-511 ; 21929262 (ISSN) ; Aashuri, H ; Nikzad, S ; Ferasat, K ; Sharif University of Technology
2017
Abstract
In this study, a combination of rapid solidification (melt-spinning) and semisolid forming (thixoforming) processes was used to refine the coarse microstructure of “as-cast” Al–30Si–5Fe alloy and improve its mechanical properties. Al–30Si–5Fe ribbons produced by the melt-spinning process were pulverized and subsequently consolidated at 300 °C in an argon atmosphere. Prepared specimens were thixoformed at temperatures ranging from 580 to 700 °C for various holding times. Some cast samples were also directly thixoformed as reference. In all thixoformed samples, microstructures were modified and needle-like intermetallic compounds as well as silicon particles in the as-cast part were changed...
Chemometrics-assisted-liquid phase microextraction based on deep eutectic solvents followed by gas chromatography for determination of polycyclic aromatic hydrocarbons in aqueous and juice samples
, Article Microchemical Journal ; Volume 191 , 2023 ; 0026265X (ISSN) ; Keyvan, N ; Nikzad, N ; Parastar, H ; Sharif University of Technology
Elsevier Inc
2023
Abstract
In the present study, an optimized liquid-phase microextraction technique based on the deep eutectic solvent (LPME-DES) followed by gas chromatography-flame ionization detector (GC-FID) is developed to determine 13 carcinogenic polycyclic aromatic hydrocarbons (PAHs) in water and juice samples. In this regard, central composite design (CCD) was used to design, multiple linear regression (MLR) to model, and Nelder-Mead simplex optimization to optimize the effective LPME-DES factors. The optimum values for DES volume, temperature, extraction time, and salt amount were 112 µL, 72 °C, 9.14 min, and 2.5% (w/v), respectively. Afterward, multivariate calibration based on partial least squares...
Resource Allocation in a Hybrid CDN-P2P Video Streaming
, M.Sc. Thesis Sharif University of Technology ; Akbari, Behzad (Supervisor) ; Khansari, Mohammad (Supervisor)
Abstract
Since the contribution bandwidth of each CDN (Content Delivery Network) node and also each peer are limited, optimal allocation of their bandwidth to their partners is an interesting issue. In this work, an efficient resource allocation algorithm in a hybrid CDN-P2P (Content Delivery Network- peer to peer) video streaming network has been designed and each peer will receive the video chunks with the bit rate according to the number of nodes that the peer supports. We have added this algorithm to Coolstreaming because it does not have a resource allocation mechanism. In Coolstreaming each peer when requests chunks from its neighbors, the neighbors will send the peer the requested chunks with...
A green closed-loop supply chain network: A bi-objective mixed integer linear programming model
, Article International Journal of Operational Research ; Volume 41, Issue 4 , 2021 , Pages 492-513 ; 17457645 (ISSN) ; Salehian, F ; Lamouchi, H ; Mina, H ; Sharif University of Technology
Inderscience Publishers
2021
Abstract
The increasing level of customer awareness and application of environmental laws by governments, on the one hand, and the increasing number of competitors, on the other hand, has obliged industry owners to include green activities in the design of the supply chain network. Green activities include any type of action that reduces environmental degradation. Hence, this study seeks to develop a bi-objective, mixed integer linear programming (MILP) model for designing a green supply chain network. In the proposed model, the minimisation of costs and detrimental environmental effects are discussed. LP metric method is used to solve the bi-objective model and the proposed model is run by using...
Automated Code Reviewer Recommendation for Pull Requests
, M.Sc. Thesis Sharif University of Technology ; Heydarnoori, Abbas (Supervisor)
Abstract
Nowadays, by distributed software development growth based on pull-requests, it is possible to review code changes before integrating into the master program by a third-party, informally and tool-based which is called Modern Code Review (MCR). Effectively performing MCR can facilitate the software evolution phase through reducing post-release defects. In MCR, after sending the pull request, the developer invites appropriate reviewers to inspect his code. Due to the high volume of requests and potential reviewers in many projects, selecting the appropriate reviewer is difficult and time consuming. Previously, a variety of recommender systems have been proposed that use methods based on...
Using Supported Ionic Liquid Membranes (SILMs) for Selective Separation of CO2/CH4
, M.Sc. Thesis Sharif University of Technology ; Rashtchian ,Davood (Supervisor) ; Adibi, Mina (Supervisor)
Abstract
Supported Ionic Liquid Membranes (SILMs) are fabricated by saturating the pores of a porous support with ionic liquids. To assess the performance of SILMS, it is necessary to obtain data about the properties of ionic liquids such as diffusivity, solubility, and etc. To accomplish this task, in this project the permeability and diffusivity of CO2 and CH4 through three immidazolium-based ionic liquids: [bmim][PF6], [hmim][Tf2N], and "1-methyl-3-(3- tri methoxi silil propyl) imidazolium bis (tri fluoro methyl solphonyl)" , in the temperature range between 27-45 ℃ and pressures within 10-50 kPa, are measured. It is shown in data validation section that the results of this study are in good...