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Magnetic field and sheet-current density of a thin type-II superconducting annulus
, Article Cryogenics ; Volume 87 , 2017 , Pages 12-17 ; 00112275 (ISSN) ; Talebi, A. H ; Sharif University of Technology
2017
Abstract
We investigate theoretically the sheet-current density and total magnetic field (MF) distribution due to a thin, type-II superconducting annulus sample. We have supposed a washer (with the inner and outer radii a and b) carrying sub-critical currents subject to an applied magnetic field. The sample is an ideal washer with no bulk pinning, under two different situations: (a) when flux is focused into the central hole and net current flowing around the washer is zero but the external field Ha=Ba/μ is on, and (b) in the presence of a potential barrier of geometrical origin. Our calculations show that the net MF is maximum in the near-edge region and in the between is weaker than other areas....
Super-hydrophilic characteristic of thermochemically prepared CdS nanocrystals
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Vol. 58 , April , 2014 , pp. 146-152 ; ISSN: 13869477 ; Taghavinia, N ; Babaei, A ; Sharif University of Technology
2014
Abstract
CdS nanocrystals were thermochemically (thermally activated) synthesized thorough the reaction between CdSO4 and Na2S 2O3 in an aqueous solution. Thioglycolic Acid (TGA) was used as the capping agent and catalyst of the reaction. The method was based on heat activated dissociation of Na2S2O3 and controllable release of S and free electrons in the solution. CdS NCs were formed by heating the sample solution at 96 C for 1 h. The results of optical spectroscopy and transmission electron microscopy demonstrated round shape NCs with sizes about 3.0 nm. The nanocrystals were also luminescent and represented a broad emission with a peak located at 515 nm and FWHM of 160 nm. Several samples were...
Compaction simulation of nano-crystalline metals with molecular dynamics analysis
, Article MATEC Web of Conferences, 4 July 2016 through 7 July 2016 ; Volume 80 , 2016 ; 2261236X (ISSN) ; Rezaei Sameti, A ; Mofatteh, H ; Babaei, M ; Sharif University of Technology
EDP Sciences
2016
Abstract
The molecular-dynamics analysis is presented for 3D compaction simulation of nano-crystalline metals under uniaxial compaction process. The nano-crystalline metals consist of nickel and aluminum nano-particles, which are mixed with specified proportions. The EAM pair-potential is employed to model the formation of nano-particles at different temperatures, number of nano-particles, and mixing ratio of Ni and Al nano-particles to form the component into the shape of a die. The die-walls are modeled using the Lennard-Jones inter-atomic potential between the atoms of nano-particles and die-walls. The forming process is model in uniaxial compression, which is simulated until the full-dense...
Evaluation of supply chain routes based on control engineering and DEA considering traffic congestion and uncertainty
, Article International Journal of Business Performance and Supply Chain Modelling ; Volume 13, Issue 2 , 2022 , Pages 139-166 ; 17589401 (ISSN) ; Khedmati, M ; Jokar, M. R. A ; Sharif University of Technology
Inderscience Publishers
2022
Abstract
In this paper, a mathematical model is proposed to assess the flow distribution based on the traffic criterion. In the mathematical model, the resilience and stability criteria are developed based on the concepts of control engineering and optimal control. The results show that the route stability is dependent on the traffic parameter. Then, considering several factors including stability, safety, resilience, risk-averse investment, the environment and noise, a decision-making model is presented to evaluate the performance of the flow distribution routes during crises. Goal programming and data-oriented modelling are used to solve the mathematical model. Data envelopment analysis (DEA) is...
Efficient hierarchical hybrid delivery in the last mile logistics
, Article European Journal of Industrial Engineering ; Volume 17, Issue 6 , 2023 , Pages 875-916 ; 17515254 (ISSN) ; Khedmati, M ; Jokar, M. R. A ; Sharif University of Technology
Inderscience Publishers
2023
Abstract
An efficient hierarchical hybrid delivery (EHHD) model is proposed by integrating a location-allocation optimisation model with a dynamic data envelopment analysis (DEA) model in this paper. The proposed model is characterised by having a periodic measurement assessing customer behaviour using the dynamic DEA, as well as developing a hierarchical connection among home delivery, the pickup point and the locker station options. The developed model considers uncertain conditions for transportation costs and customer behaviour. To solve this model, a meta-goal programming approach has been used. Based on the results of the numerical experiments, the developed model has a better performance than...
Erratum to “a combined multi-objective multi criteria approach for blockchain-based synchromodal transportation” [comput. ind. eng. 176 (2023) 108996] (computers & industrial engineering (2023) 176, (s0360835223000207), (10.1016/j.cie.2023.108996))
, Article Computers and Industrial Engineering ; Volume 184 , 2023 ; 03608352 (ISSN) ; Shafaei, A ; Akbari Jokar, M. R ; Sharif University of Technology
Elsevier Ltd
2023
A branch and efficiency algorithm to design a sustainable two-echelon supply chain network considering traffic congestion and uncertainty
, Article Environmental Science and Pollution Research ; Volume 30, Issue 10 , 2023 , Pages 28274-28304 ; 09441344 (ISSN) ; Khedmati, M ; Jokar, M. R. A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2023
Abstract
This work aims to design a sustainable two-echelon supply chain not only based on the widely used cost perspective, but also based on the efficient use and preservation of limited resources. For this purpose, a branch and efficiency (B&E) algorithm is developed, which includes an optimization model and an evaluation model. The proposed tri-objective optimization model simultaneously minimizes the total cost of the supply chain, maximizes the sustainability score, and minimizes inequity among customers. The solutions obtained from the optimization model are then evaluated by extended data envelopment analysis (EDEA) models based on common criteria (i.e., cost and service) and traffic...
Thermodynamic and transport properties estimation of a complicated mixture of hydrocarbons by fuzzy clustering methods
, Article 19th International Congress of Chemical and Process Engineering, CHISA 2010 and 7th European Congress of Chemical Engineering, ECCE-7, 28 August 2010 through 1 September 2010 ; 2010 ; Ahmadi Orkomi, A ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
2010
Abstract
Clustering is the term used in several research communities to describe methods for grouping of unlabeled data. The objective in clustering is to divide the data set in such a way that the intra-class similarity is high and inter-class similarity is low. It is very helpful to find a system's states distributions, but when the system's scale is large, e.g., considering a distillation column that has crude oil as its feed, if one of desired is finding concentration of most popular hydrocarbons (ethane, propane, octane, etc.) on each tray, it should be solve species continuity for each component. A mixture of 100 hydrocarbons was classified into 10 clusters by different clustering methods,...
Municipal wastewater treatment and fouling in microalgal-activated sludge membrane bioreactor: Cultivation in raw and treated wastewater
, Article Journal of Water Process Engineering ; Volume 49 , 2022 ; 22147144 (ISSN) ; Shamskilani, M ; Babaei, A ; Behrang, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Since the advent of conventional activated sludge biological treatment plants, their low efficiency in nitrogen and phosphorus removal has become a significant concern. Therefore, in this study, the performance of microalgal-activated sludge membrane bioreactor (MAS-MBR) as a self-biological treatment or as a post-treatment for conventional biological treatments was investigated. A continuous MAS-MBR with two ratios of algae/sludge (only microalgae and 5:1) was used to treat raw and treated wastewater. The optimum case was achieved with the cultivation of mixed algae/sludge in raw wastewater (R2 case). In this case, the ammonium and phosphorus removal efficiencies were 94.36 ± 3.5 and 88.37...
Review of data science trends and issues in porous media research with a focus on image-based techniques
, Article Water Resources Research ; Volume 57, Issue 10 , 2021 ; 00431397 (ISSN) ; Fernando, A. M ; Shams, R ; Singh, A ; Mostaghimi, P ; Babaei, M ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Data science as a flourishing interdisciplinary domain of computer and mathematical sciences is playing an important role in guiding the porous material research streams. In the present narrative review, we have examined recent trends and issues in data-driven methods used in the image-based porous material research studies relevant to water resources researchers and scientists. Initially, the recent trends in porous material data-related issues have been investigated through search engine queries in terms of data source, data storage hub, programing languages, and software packages. Subsequent to a diligent analysis of the existing trends, a review of the common concepts of porous material...
Modeling catalyst deactivation in dehydrogenation of ethylbenzene to styrene
, Article 11AIChE - 2011 AIChE Spring Meeting and 7th Global Congress on Process Safety, Conference Proceedings ; 2011 , Pages - ; 9780816910670 (ISBN) ; Baghalha, M ; Sharif University of Technology
American Institute of Chemical Engineers
2011
Abstract
The long-term deactivation of a commercial K-promoted Fe2O3 catalyst used in the dehydrogenation of ethylbenzene to styrene monomer was investigated using 30 mo of operating data of three industrial SM radial fixed bed adiabatic reactors. The Langmuir-Hinshelwood, Hougen-Watson model was used for reaction kinetics modeling. The kinetics of coking from ethylbenzene and styrene and the short-term deactivation function due to the quick coke formation were considered in the model. The kinetics of long-term deactivation of the catalyst for ethylbenzene dehydrogenation to styrene at 550°-630°C were determined. Unknown parameters of the long-term activity function, related to the slow loss of...
Modeling catalyst deactivation in dehydrogenation of ethylbenzene to styrene
, Article AIChE Annual Meeting, Conference Proceedings, 13 March 2011 through 17 March 2011 ; March , 2011 ; 9780816910670 (ISBN) ; Baghalha, M ; Sharif University of Technology
2011
Abstract
Long-term deactivation of a commercial K-promoted Fe 2O 3 catalyst used in the dehydrogenation of ethylbenzene to styrene monomer was studied using 30 months of operating data of three industrial SM radial fixed bed adiabatic reactors. The Langmuir-Hinshelwood, Hougen-Watson model (LHHW) was used for reaction kinetics modeling. The kinetics of coking from ethylbenzene and styrene and the short-term deactivation function due to the quick coke formation were also considered in the model. The kinetics of long-term deactivation of the catalyst for ethylbenzene dehydrogenation to styrene between 550 and 630 °C were determined by allowing the effects of temperature and time on the catalyst...
Effects of temperature and mixing modes on the performance of municipal solid waste anaerobic slurry digester 09 Engineering 0907 Environmental Engineering 09 Engineering 0904 Chemical Engineering
, Article Journal of Environmental Health Science and Engineering ; Volume 17, Issue 2 , 2020 , Pages 1077-1084 ; Shayegan, J ; Sharif University of Technology
Springer
2020
Abstract
Purpose: Anaerobic digestion is a promising technology for simultaneous treatment of biodegradable organic matter of municipal solid waste (MSW) and production of renewable energy. Mixing modes and temperature have influences on biogas production in anaerobic digesters treating MSW. Therefore, in this study, digester was operated at different modes of mixing and temperatures to obtain design criteria. Methods: The experiments were carried out in a semi-continuous digester. In the first part of the investigation, temperature was set at 25, 28, 31 and 34 °C. During this step, digester content was mixed in an intermittent mode by mechanical mixers. In the second part of the study, mixing...
Traffic Source Particle Pollution Distribution Using Micro-scale Simulation
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor)
Abstract
Today air pollution has become one of the major urban management concerns. Air pollution could have dangerous effects on human health in short time or long time in many situations. Numerical modelling is one of the most applicable among different ways for predicting pollutant concentration like field measurement, physical model in wind tunnel, and simulation. Modelling of pollutant dispersion is a way for estimating concentration and aggregation of the pollutant near the surface and with different distances from pollution source. In different dispersion models, one of simplest is the Gaussian model. In this approach it is supposed that emission plume obeys from Gaussian distribution and is...
Point to point Control of a Brachiation Robot Based on Neural Network
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor)
Abstract
• Brachiation robot is a kind of under-actuated robots. A brachiating robot is a type of a mobile arm that is capable of moving from branch to branch similar to a long-armed ape. The purpose of this thesis is control of a two link Brachiation robot. The purpose of this thesis is control of a two link Brachiation robot using neural network and geometry control. For this purpose a genetic algorithm based training Neural Network is used to produce a suitable path for the second link of the robot and then using input-output linearization method, the second link is controlled to follow the path. The simulations shows that the Nero Controller designed in this thesis is suitable. The controller can...
Seismic Rehabilitation of Irregular Steel Structures Using Friction Dampers
, M.Sc. Thesis Sharif University of Technology ; Moghaddam, Hassan (Supervisor)
Abstract
The purpose of this study was to find the optimal position and slip force of friction dampers, for improving the seismic performance of regular and irregular steel structures and comparison of dampers final pattern of these buildings.In this regard, one to six floor regular and irregular buildings were designed. These buildings were modeled three-dimensionally in the OpenSees Software, and were subjected to horizontal components of seven far field accelerogram in order to investigate the need for their rehabilitation. The results of the time history analysis of these buildings showed that inter-story drifts exceeds the acceptance criteria which has been assumed 2.5% according to the Life...
Cryptanalysis of a Class of McEliece-like Code-Based Signature Schemes
, M.Sc. Thesis Sharif University of Technology ; Eghlidos, Taraneh (Supervisor)
Abstract
With the advent of quantum computers, the security of cryptographic primitives, including digital signature schemes, has been compromised. Therefore, a kind of signature scheme has been introduced to resist these computers. These schemes are based on hard problems that have so far resisted against quantum computers, known as post-quantum schemes. One group of these schemes is based on the hard problems of coding theory, which are called code-based cryptographic schemes. The first code-based cryptosystem was the McEliece encryption scheme. A number of code-based signature schemes are based on the McEliece encryption scheme. Some of these schemes use three matrices including a non-singular...
An integrated decision support system to achieve sustainable development in transportation routes with traffic flow
, Article Environmental Science and Pollution Research ; Volume 30, Issue 21 , 2023 , Pages 60367-60382 ; 09441344 (ISSN) ; Khedmati, M ; Jokar, M. R. A ; Tirkolaee, E. B ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2023
Abstract
Due to the growing population and demand, transportation planning has received special importance in the context of supply chain management. One of the major challenges in transportation planning is the traffic problem. This challenge affects the safety, environmental, and efficiency factors of transportation systems. Accordingly, in this study, the routes, which are important pillars of transportation planning, are examined from the perspective of sustainability. In this regard, a novel decision support system is developed, wherein at first, some decision-making methods including Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), entropy technique, Nash equilibrium...
Probabilistic tolerance analysis of compliant assemblies
, Article 2007 World Congress, Detroit, MI, 16 April 2007 through 19 April 2007 ; 2007 ; 01487191 (ISSN) ; Movahhedy, M. R ; Sharif University of Technology
SAE International
2007
Abstract
Tolerance analysis is essential for estimation of final error of key product characteristic (KPC) in a mechanical assembly caused by errors in production and assembly of individual parts. Many mechanical assemblies, especially in automotive and aerospace industries, include sheet metal parts with a small ratio of thickness to width or length. Such parts are substantially flexible and thus, are prone to large errors due to elastic deformations during assembly production. Phenomena such as deformation due to fixture force, spring back, welding distortion and so on are common to such parts. Unlike tolerance analysis of rigid parts, here, the elastic deformation of the parts plays a significant...
Fabrication and Characterization of Nickel-Cobalt Catalyst by One-pot Combustion Synthesis Method for Synthesis Gas Production in Dry Reforming Methane Process
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
Dry reforming methane is a process during which two greenhouse gases, CH4 and CO2, using Ni-based catalysts, are altered into valuable H2 and CO gases, which are very useful from an economic and environmental point of view. The main problem with Ni-based catalysts is the formation of carbon in the dry methane reforming, which leads to rapid deactivation of the catalyst. In this research, a 10Ni-5Co/Al2O3 bimetallic catalyst was prepared by one-pot microwave-assisted combustion synthesis with a stoichiometric amount of fuel (urea) and without the use of additives. The catalyst was then calcined for 12 h at 550oC. The structure, chemical composition, particle distribution, and morphology of...