Search for: modelling-method
M.Sc. Thesis Sharif University of Technology ; Farshchi, Mohammad ; Hajilou benisi, Ali
Gas turbine design and manufacturing is a complex process. It requires a true understanding of turbo machinery, materials, and manufacturing technologies. Current studyfocuses onthe design and test of a small turbo jet which is benefitted from a turbocharger. Zero dimensional analysis of engine cycle is done with MATLAB and results of program is utilized to design the combustion chamber and calibrating the nozzle. For determination of combustion chamber size, a reactor modelling is used. Simulation of flow in combustion chamber is done with a commercial program (Fluent) in order to determine other specification of combustion chamber such as hole sizing, diverging angle and etc....
Article 20th IEEE International Conference on Computer Supported Cooperative Work in Design, 4 May 2016 through 6 May 2016 ; 2016 , Pages 174-179 ; 9781509019151 (ISBN) ; Movassagh, A. A ; Qin, Y ; Yong, J ; Tao, X ; Zhang, J ; Shen, H ; Liu, X. P ; Yong, J ; Barthes, J. P ; Shen, W ; Yang, C ; Luo, J ; Chen, L ; IEEE Systems, Man, and Cybernetics Society; International Working Group on Computer Supported Cooperative Work in Design (CSCWD) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Sensor networks usually generate mass of data, which if not structured for future applications, will require much effort on analytical processing and interpretations. Thus, storing sensor data in an effective and structured format is a key issue in the area of sensor networks. In the meantime, even a little improvement on data storing structure may lead to a significant effect on the lifetime and performance of the sensor network. This paper describes a new method for sensor storage that combines semantic web concepts, a data aggregation method along with aligning sensors in hierarchical form. This solution is able to reduce the amount of data stored at the sink nodes significantly. At the...
Article Optics Communications ; Volume 281, Issue 14 , 2008 , Pages 3673-3680 ; 00304018 (ISSN) ; Farman, F ; Ghasempour, A ; Sharif University of Technology
We aim to propose a novel fiber Raman amplifier modeling based on the moment method, which is previously introduced for modeling the inhomogeneous Erbium doped fiber amplifiers and recently employed to analyze the fiber Raman amplifier with continuous pump spectrum. In this model, the number of governing equations is independent of the number of signals and according to the degree of accuracy it is proportional to the number of pumps. This method is employed to analyze the Raman fiber amplifiers with an arbitrary input signal line shape and to minimize the gain ripple of the fiber Raman amplifier with respect to the pump powers and pump frequencies. © 2008 Elsevier B.V. All rights reserved
Article IFAC Proceedings Volumes (IFAC-PapersOnline), 7 June 2015 through 10 June 2015 ; Volume 48, Issue 8 , 2015 , Pages 315-320 ; 14746670 (ISSN) ; Shahrokhi, M ; Abedini, H ; Vafa, E ; Guay, M ; Gopaluni, B ; Huang, B ; Findeisen, R ; Sharif University of Technology
IFAC Secretariat 2015
A detailed pseudo-bulk model has been used for prediction of conversion and particle size distribution (PSD) of vinyl acetate in a continuous emulsion polymerization reactor. Finite volume (FV) and moment techniques are applied for solving population balance equation under continuous operation. It is found that both methods can predict sustained oscillations in the monomer conversion, however the FV method matches the experimental data better than the moment method. The monomer conversion and free surfactant concentration are controlled via two single control loops. In this work, a new control strategy for controlling monomer conversion has been proposed. It has been shown that monomer...
Hybrid finite-element method-molecular dynamics approach for modelling of non-contact atomic force microscopy imaging, Article Micro and Nano Letters ; Volume 6, Issue 6 , June , 2011 , Pages 412-416 ; 17500443 (ISSN) ; Mahboobi, S. H ; Meghdari, A ; Sharif University of Technology
Models capable of accurate simulation of the microcantilever dynamics coupled with complex tip-sample interactions are essential for interpretation of the imaging results in non-contact atomic force microscopy (AFM). In the present research, a combination of finite element and molecular dynamics methods are used for modelling the AFM system to overcome the drawbacks of conventional approaches that use a lumped system with van der Waals interaction. To illustrate the ability of the proposed scheme in providing images with atomic resolution, some simulations have been performed. In the conducted simulations, a diamond tip is interacting with nickel samples having different surface plane...
Article IEEE Transactions on Industrial Electronics ; Volume 58, Issue 3 , 2011 , Pages 949-959 ; 02780046 (ISSN) ; Mokhtari, H ; Chang, L ; Sharif University of Technology
In this paper, a new simple and complete technique of modeling and analysis of a matrix converter is presented based on the singular value decomposition (SVD) of modulation matrix. The proposed modeling method yields a new limitation between the matrix converter gain and its input power factor, which is more relaxed as compared to the limits reported so far in the literature. The SVD of the modulation matrix leads to a unified modulation technique which achieves the full capability of a matrix converter. It is shown that this approach is general and all other modulation methods established for a matrix converter are specific cases of this technique. The proposed modulation method can be used...
Article Proceedings - Asia-Pacific Software Engineering Conference, APSEC, 30 November 2010 through 3 December 2010, Sydney, NSW ; 2010 , Pages 326-335 ; 15301362 (ISSN) ; 9780769542669 (ISBN) ; Hasani Sadi, M ; Ramsin, R ; Sharif University of Technology
Various agile software development methodologies, practices, and techniques have been proposed in the last decade; some present novel ideas, while many are simply made up of tasks and techniques borrowed from prominent agile methodologies. Each of these methodologies prescribes a set of practices and techniques which are deemed appropriate for application in a specific context. However, there exists no single method which fits all project situations. This has resulted in the advent of Situational Method Engineering (SME) approaches, which are used for developing software methodologies that are tailored to fit the specific circumstances of the project situation at hand. Since tool support has...
Article IEEE Aerospace Conference Proceedings, 6 March 2010 through 13 March 2010 ; March , 2010 ; 1095323X (ISSN) ; 9781424438884 (ISBN) ; Hajilouy Benisi, A ; Farshchi, M ; Sharif University of Technology
In the conceptual design phase of a turbocharger, where emphasis is mainly on parametric studies, before manufacturing and tests, a generalized and robust model that applies over a wide range properly, is unavoidable. 12The critical inputs such as turbine maps are not available during the conceptual design phase. Hence, generalized turbine models use alternate methods that work without any supplementary tests and can operate over wide ranges. One of the common and applicable modeling methods in design process is 'Dimensionless Modeling' using the constant coefficient scaling (CCS). This method can almost predict the turbine characteristics at the design point. However, at off-design...
Article Journal of Mechanics ; Volume 26, Issue 1 , 2010 , Pages 37-45 ; 17277191 (ISSN) ; Hajilouy Benisi, A ; Farshchi, M ; Sharif University of Technology
In the conceptual design phase of a turbocharger, where emphasis is mainly on parametric studies, before manufacturing and tests, a generalized and robust model that implies over a wide range properly, is unavoidable. The critical inputs such as compressor maps are not available during the conceptual design phase. Hence, generalized compressor models use alternate methods that work without any supplementary tests and can operate on wide range. One of the common and applicable modeling methods in design process is the 'Dimensionless Modeling' using the constant coefficient scaling (CCS). This method almost can predict the compressor characteristics at design point. However, at off design...
Article 2007 Workshop on Computational Electromagnetics in Time-Domain, CEM-TD, Perugia, 15 October 2007 through 17 October 2007 ; 2007 ; 142441170X (ISBN); 9781424411702 (ISBN) ; Banai, A ; Farzaneh, F ; Sharif University of Technology
Stability has been one of the major issues of time-domain numerical methods used for solving Maxwell equations. This problem takes a more severe form when additional algorithms are introduced to the computation domain (e.g. Absorbing Boundary Conditions-ABCs). There are a number of methods for investigating the stability of a simulation. In this article the problem of stability of ABCs, has been tackled through a control system's state-space point of view. Thus, occurrence of instability in a simulation can be predicted. © 2007 IEEE
Article 1st International Conference on Advances and Trends in Engineering Materials and their Applications, AES-ATEMA'2007, Montreal, QC, 6 August 2007 through 10 August 2007 ; 2007 , Pages 525-533 ; 19243642 (ISSN) ; 0978047907 (ISBN); 9780978047900 (ISBN) ; Farrokh, M ; Mohebbi, M ; Sharif University of Technology
In this paper a new method of modeling shear force-displacement relationship for confined masonry walls by neural networks has been presented. Although the mathematical models have been very useful in the simulations so far, however developing more accurate models is necessary. While developing precise mathematical models for highly hysteretic materials is itself challenging and practically cumbersome, the use of learning algorithms is an attractive alternative. The issue of material modeling by neural networks has been a challenging one itself, noticing available neural networks have some limitations in the learning of non-linearity. In this paper a new type neural network, called Prandtl...
Article SPE Saudi Arabia Section Technical Symposium 2007, 7 May 2007 through 8 May 2007 ; 2007 ; 9781555639600 (ISBN) ; Schaale, M ; Shouraki, S. B ; Fell, F ; Fischer, J ; Taheri, M ; Preusker, R ; Tajrishy, M ; Vatandoust, M ; Shahraeini, M. T ; Sani, P.N ; Taherishahraini, Z ; Khodaparast, H ; Sharif University of Technology
Society of Petroleum Engineers 2007
All of the man-made objects and anthropogenic activities related to the oil industries in water bodies (e.g. drilling, equipment installation, construction of oil platfonns and especially oil spillages) have enviromnental impacts on water ecosystems. The assessment of oil field operations and oil platfonns impacts on water quality have become a necessity throughout the world. Phytoplanktons have the lowest trophic level in water enviromnent; therefore the life of all of the other marine animals is highly relevant to phytoplanktonic population. Hence it seems necessary to monitor the spatiotemporal effects of different activities and events, related to oil industries on phytoplanktons....
Mathematical modeling and statistical analysis of second harmonic generation effects with thin and thick crystals in ultrahigh-speed optically amplified digital lightwave communication systems, Article Journal of Lightwave Technology ; Volume 27, Issue 16 , 2009 , Pages 3438-3452 ; 07338724 (ISSN) ; Salehi, J. A ; Sharif University of Technology
In this paper, we present an in depth analysis and discussions on the behavior and performance of using either thin or thick second harmonic generation (SHG) crystals prior to photodetector in ultrahigh-speed optically amplified digital lightwave communication systems. Our study begins by considering a conventional low-speed optically amplified lightwave receiver and study its performance in ultrahigh-speed regime and show its substantially degraded behavior, indicating the need to use advance optical nonlinear elements such as SHG prior to photodetection. In studying SHG effects, we begin by discussing the mathematical models of thin and thick SHG crystals in the context of statistical...
Modeling and preparation of activated carbon for methane storage I. modeling of activated carbon characteristics with neural networks and response surface method, Article Energy Conversion and Management ; Volume 49, Issue 9 , September , 2008 , Pages 2471-2477 ; 01968904 (ISSN) ; Soltanieh, M ; Rashidi, A ; Irandoukht, A ; Sharif University of Technology
Numerous methods have been proposed previously to describe the characterization of porous materials; however, no well-developed theory is still available. Three different modeling methods were employed in this study to explore the relationship between the characterization parameters of activated carbon (AC) and its methane uptake. The first and the second methods were based on the Radial Basis Function (R.B.F) neural networks. At the first R.B.F. modeling, the neural networks algorithm was designed using the Gaussian function. The collected data for modeling were divided into two parts; (i) the data used for training the network and (ii) the data used for testing the predicted network. At...