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mixing
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Damage-plasticity model for mixed hinges in steel frames
, Article Journal of Constructional Steel Research ; Volume 67, Issue 8 , 2011 , Pages 1272-1281 ; 0143974X (ISSN) ; Asl, M. H ; Sharif University of Technology
2011
Abstract
A damage-plasticity based mixed axial-shear-flexural (PVM) link element for the inelastic analysis of frames is introduced in this paper. The multi-surfaces yield concept is utilized in the definition of the element. The yield surfaces are defined in deformation space and interaction of axial-shear-flexural deformations is considered by defining non-rectangular yield surfaces. The element is capable of considering damage and post-peak softening behavior. The analytical results of introduced element are verified by existing experimental results of steel beam to column connection and it is indicated that the analytical results have reasonable agreement with the test results. Nonlinear dynamic...
A GA/TS algorithm for the stage shop scheduling problem
, Article Computers and Industrial Engineering ; Volume 61, Issue 1 , 2011 , Pages 161-170 ; 03608352 (ISSN) ; Kianfar, F ; Sharif University of Technology
Abstract
This paper presents a special case of the general shop called stage shop problem. The stage shop is a more realistic generalization of the mixed shop problem. In the stage shop problem, each job has several stages of operations. In order to solve the stage shop problem with makespan objective function, an existing neighborhood of job shop is used. In this neighborhood, few enhanced conditions are proposed to prevent cycle generation. In addition, a new neighborhood for operations that belong to the same job is presented. These neighborhoods are applied to the stage shop problem in a tabu search framework. A genetic algorithm is used to obtain good initial solutions. An existing lower bound...
A market mechanism to quantify emergency energy transactions value in a multi-microgrid system
, Article IEEE Transactions on Sustainable Energy ; 2017 ; 19493029 (ISSN) ; Ghorani, R ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Abstract
In this paper, a new market mechanism is proposed to quantify the value of emergency energy transactions in renewable-based multi-microgrid (MMG) systems. To reach this goal, main requirements and features of such emergency market are identified. Subsequently, a hybrid market framework is proposed which integrates pool emergency transactions and bilateral contracts in order to reduce the system risk in face of different contingency events. For settling different transactions in this market, the main procedure which should be followed by distribution system operator (DSO) to properly address bidding of microgrids (MGs) as well as system technical constraints are introduced. In addition, a...
Mixed paths and cycles determined by their spectrum
, Article Linear Algebra and Its Applications ; Volume 586 , 2020 , Pages 325-346 ; Ghafari, A ; Nahvi, M ; Nematollahi, M. A ; Sharif University of Technology
Elsevier Inc
2020
Abstract
A mixed graph is obtained from a graph by orienting some of its edges. The Hermitian adjacency matrix of a mixed graph with the vertex set {v1,…,vn}, is the matrix H=[hij]n×n, where hij=−hji=i if there is a directed edge from vi to vj, hij=1 if there exists an undirected edge between vi and vj, and hij=0 otherwise. The Hermitian spectrum of a mixed graph is defined to be the spectrum of its Hermitian adjacency matrix. In this paper we study mixed graphs which are determined by their Hermitian spectrum (DHS). First, we show that each mixed cycle is switching equivalent to either a mixed cycle with no directed edges (Cn), a mixed cycle with exactly one directed edge (Cn 1), or a mixed cycle...
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...
Optimisation of deep mixing technique by artificial neural network based on laboratory and field experiments
, Article Georisk ; Volume 14, Issue 2 , 2020 , Pages 142-157 ; Mojtahedi, S. F. F ; Sadeghi, H ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Ground improvement techniques are inevitable for weak soils that cannot endure the design load imposed by superstructures. Deep mixing technique (DMT) as one of these methods is promising and effective when a deep soil layer with low bearing capacity is encountered. Such deposits are quite common in the South-west of Iran where the studied site is located. In order to validate the influence of DMT on the enhancement of strength, both in-situ and laboratory tests were conducted. Afterwards, a parametric study was carried out to investigate the influence of key factors including cement content, water–cement ratio, curing time and plasticity index (PI) on the performance of DMT. In summary, a...
Estimating the mixing matrix in underdetermined Sparse Component Analysis (SCA) using consecutive independent component analysis (ICA)
, Article 16th European Signal Processing Conference, EUSIPCO 2008, Lausanne, 25 August 2008 through 29 August 2008 ; 2008 ; 22195491 (ISSN) ; Pad, P ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2008
Abstract
One of the major problems in underdetermined Sparse Component Analysis (SCA) is the appropriate estimation of the mixing matrix, A, in the linear model x(t) = As(t), especially where more than one source is active at each instant of time (It is called 'multiple dominant problem'). Most of the previous algorithms were restricted to single dominant problem in which it is assumed that at each instant, there is at most one single dominant component. Moreover, because of high computational load, all present methods for multiple dominant problem are practical only for small scale cases (By 'small scale' we mean that the average number of active sources at each instant, k, is less than 5). In this...
Estimating the mixing matrix in sparse component analysis (SCA) using em algorithm and iterative bayesian clustering
, Article 16th European Signal Processing Conference, EUSIPCO 2008, Lausanne, 25 August 2008 through 29 August 2008 ; 2008 ; 22195491 (ISSN) ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2008
Abstract
In this paper, we focus on the mixing matrix estimation which is the first step of Sparse Component Analysis. We propose a novel algorithm based on Expectation- Maximization (EM) algorithm in the case of two-sensor set up. Then, a novel iterative Bayesian clustering is applied to yield better results in estimating the mixing matrix. Also, we compute the Maximum Likelihood (ML) estimates of the elements of the second row of the mixing matrix based on each cluster. The simulations show that the proposed method has better accuracy and less failure than the EM-Laplacian Mixture Model (EM-LMM) method. copyright by EURASIP
Estimating the mixing matrix in Sparse Component Analysis (SCA) based on multidimensional subspace clustering
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 670-675 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Mohimani, G. H ; Babaiezadeh, M ; Jutten, C ; Sharif University of Technology
2007
Abstract
In this paper we propose a new method for estimating the mixing matrix, A, in the linear model X = AS, for the problem of underdetermined Sparse Component Analysis (SCA). Contrary to most existing algorithms, in the proposed algorithm there may be more than one active source at each instant (i.e. in each column of the source matrix S), and the number of sources is not required to be known in advance. Since in the cases where more than one source is active at each instant, data samples concentrate around multidimensional subspaces, the idea of our method is to first estimate these subspaces and then estimate the mixing matrix from these estimated subspaces. ©2007 IEEE
Continuous solid-state fermentation as affected by substrate flow pattern
, Article Chemical Engineering Science ; Volume 61, Issue 8 , 2006 , Pages 2675-2687 ; 00092509 (ISSN) ; Mitchell, D. A ; Beheshti, M ; Roostaazad, R ; Sánchez, L. R ; Sharif University of Technology
2006
Abstract
The performance of continuous solid state bioreactors having two different solid substrate flow patterns, namely plug flow and completely mixed flow, is quantified for both steady-state and transient operation using a simple mathematical model. The core assumption is that each substrate particle acts as an infinitesimal bioreactor. The residence time distribution of the particles is considered in the formulation of the equations for the mixed-flow bioreactor and the error that results from neglecting it is investigated by comparing the simulation results with those of a completely mixed, continuous bioreactor for submerged liquid fermentation (a chemostat). The model is extended to include...
Impact of injection parameters on mixing control by polymer-enhanced low-salinity waterflooding
, Article Energy and Fuels ; Volume 36, Issue 19 , 2022 , Pages 11808-11816 ; 08870624 (ISSN) ; Rostami, B ; Mahani, H ; Sharif University of Technology
American Chemical Society
2022
Abstract
In situ mixing by dispersive transport of salt and viscous fingering between the injected low-salinity (LS) brine and high-salinity (HS) formation brine can jeopardize the performance of low-salinity waterflooding (LSWF). In our previous papers, we demonstrated that in situ mixing can be suppressed by polymer-enhanced low-salinity waterflooding (PELS), in which a small amount of a viscosifying agent, such as a polymer, is added to the LS stream. Nevertheless, effective mixing control with PELS depends upon several factors and operational conditions, which have not yet been addressed. Therefore, this research focuses on the investigation of the impact of injection parameters, such as the...
Reactive Crystallization in an Impinging Jets Reactor
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Reactive crystallization or precipitation is an important industrial process. Many chemicals and biochemicals such as catalysts and pigments are produced by precipitation. Because of the advantages of impinging jets in chemical engineering processes, the main aim of this research was to investigate the application of this method in precipitation and to study the effects of different operating and design parameters on the product’s quality and properties. Two chemical models of barium sulfate and copper oxalate were used as main products. Each of these chemicals was produced by a liquid-liquid reaction of two aqueous solutions, which were fed to an impinging-jets reactor. Effects of...
Essential Factors Affect Consumer Buying Decision Adapted by Snowa Company With Reference to Refrigerator
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Alireza (Supervisor) ; Birjandi, Heshmat (Supervisor)
Abstract
Consumers make buying decisions every day and managers or marketers try to understand why, when, where and how consumers make decisions to buy a product. One complex duty of managers is to understand consumer buying behavior in order to adapt their effort to consumers’ interest. Many studies gathered possible influent factors on consumer buying decisions that should consider as a basic of marketing strategy effort. In this time due to appearance large competitors and producers in the market of home appliance in Iran, consumers have more choice to select and purchase one product among different brands. In addition, high volume of advertizing, consistency of preliminary attribute among...
Vortex Dynamics in Magnetic Phase Diagram of High Tc Cuprate Oxides
, M.Sc. Thesis Sharif University of Technology ; Khosroabadi, Hossein (Supervisor) ; Akhavan, Mohammad (Supervisor)
Abstract
In the 1950s, Abrikosov predicted the mixed state in superconductors (type II superconductors) which lead to a Noble Prize in 2003 with the experimental verification by shubnikov. Mixed-state is a network of magnetic flux lines with quantized flux (vortices) in superconductors. High-temperature superconductors are of Type II which the existense of vortices in a significant part of the temperature-field phase diagram of them, is an obvious phenomenon. These superconductors provided a proper context for understanding physical phenomena related to vortices and access to experimental data to compare with those provided by statistical mechanics. Vortices can move inside the superconductor by the...
Preparation and Characterization of Ternary Mixed Oxide Containing IrO2,RuO2,TiO2 on Platinum Coated Titanium Anode
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Davami, Parviz (Supervisor)
Abstract
Ruthenium based-oxide coatings on Titanium anodes are widely used as DSA (Dimensionally Stable Anode) for chlorine and chlorate production. Coatings consisting of composition of highly conductive oxide of noble metals (Ru, Ir and Pt) make them as long lasting anodes in chlor-alkali technology.In this work, a newly anode by a ternary coating of IrO2, RuO2, and TiO2 on the Pt-coated Ti was developed through thermal decomposition of iridium and titanium and ruthenium inorganic salts dissolved in n-pentane. The effect of deposition parameters such as current density, time, different condition of baking, heating, mole ratio and pulling up the samples was investigated to find out reasonable...
Analyze and Improvement of Secret Handshake Protocols
, M.Sc. Thesis Sharif University of Technology ; Mohajeri, Javad (Supervisor) ; Salmasizadeh, Mahmoud (Supervisor)
Abstract
In today's world in which a major part of information is digitalized and a large portion of the communication is done via computer networks, entities authentication while maintaining privacy is a concern with the growing importance and value. To meet this goal, during the past two decades, anonymous authentication protocols with different approaches for use in various applications has presented and developed. These protocols enable users to authenticate based on some of their properties, without revealing their own identities. Secret handshake protocols are considered as type of anonymous authentication protocols. This protocol has the unique feature of hiding users' affiliation to the...
Hybrid modeling and control of a DC-DC boost converter via Extended Mixed Logical Dynamical systems (EMLDs)
, Article PEDSTC 2014 - 5th Annual International Power Electronics, Drive Systems and Technologies Conference ; 2014 , pp. 373-378 ; Mokhtari, H ; Sharif University of Technology
Abstract
The objective of this paper is to expand the concept of hybrid modeling and control in power electronics area. A new precise and non-averaged model of a DC-DC boost converter is developed on the basis of Mixed Logical Dynamical (MLD) systems, and the approach is extended by a new version of such systems which is called as Extended Mixed Logical Dynamical (EMLD) systems in this paper. A Model Predictive Controller (MPC) based on the Mixed Integer Quadratic Programming (MIQP) is designed for the MLD and EMLD models of the DC-DC boost converter considering all possible dynamics in Continuous and Discontinuous Conduction Modes of operations (CCM-DCM). The simulation results show the satisfactory...
Randomized partial checking revisited
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 7779 LNCS , February , 2013 , Pages 115-128 ; 03029743 (ISSN) ; 9783642360947 (ISBN) ; Wikstrom, D ; Sharif University of Technology
2013
Abstract
We study mix-nets with randomized partial checking (RPC) as proposed by Jakobsson, Juels, and Rivest (2002). RPC is a technique to verify the correctness of an execution both for Chaumian and homomorphic mix-nets. The idea is to relax the correctness and privacy requirements to achieve a more efficient mix-net. We identify serious issues in the original description of mix-nets with RPC and show how to exploit these to break both correctness and privacy, both for Chaumian and homomorphic mix-nets. Our attacks are practical and applicable to real world mix-net implementations, e.g., the Civitas and the Scantegrity voting systems
Study of microstructure and dielectric properties of PMN-PZT ceramics via a mixed powder method including microemulsion derived PZT powder
, Article Malaysian Journal of Microscopy ; Volume 7, Issue 1 , 2011 , Pages 43-47 ; 18237010 (ISSN) ; Nemati, Z. A ; Meenaloshini, S ; Sankar, U ; Tolouei, R ; Rahmanifar, M. S ; Ramesh, S ; Sharif University of Technology
Abstract
In this research, (X)PZT-(1-X)PMN ceramics (where X is 0.25, 0.5 and 0.75) were achieved from a conventional mixed-oxide method. Lead Zirconate titanate (PZT) powders with composition near the morphotropic phase boundary have been synthesized via a microemulsion processing route. Modified mixed oxides method was used for obtaining single phase Lead Magnesium niobate (PMN) powder with high relative density (98% of T.D.) and good electrical properties (dielectric constant of ≈10 4 at room temperature). Two-step sintering (TSS) has been applied to suppress the accelerated grain growth of PZT-PMN composite compacts in the last sintering stage. The produced samples with high PZT content showed...
Planning a capacitated road network with flexible travel times: a genetic algorithm
, Article Journal of Mathematical Modelling and Algorithms in Operations Research ; Volume 14, Issue 4 , December , 2015 , Pages 425-451 ; 2214-2487 (ISSN) ; Mahdavi Amiri, N ; Mahdavi, I ; Sharif University of Technology
Botanical Society of America Inc
2015
Abstract
We are concerned with a capacitated location-multi allocation-routing problem in a road network with flexible travel times. It is assumed that all links are two-way and capacities of the server nodes and arcs for accepting of population are limited. The aim of our work is to find numbers and locations of server nodes, allocation of the existing population in existing demand nodes on the network to the servers and the allocation of existing population in each node to different routes to determine the decided server for each member so that total transportation time is minimized. Here, two basic concepts are considered: multi allocation and flexible travel times. The concept of multi allocation...