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Experimental measurement and modeling of saturated reservoir oil viscosity
, Article Korean Journal of Chemical Engineering ; Vol. 31, Issue. 7 , 2014 , pp. 1253-1264 ; ISSN: 02561115 ; Majidi, S. M. J ; Mahmoudi, B ; Ramazani, S. A A ; Mohammadi, A. H ; Sharif University of Technology
Abstract
A novel mathematical-based approach is proposed to develop reliable models for prediction of saturated crude oil viscosity in a wide range of PVT properties. A new soft computing approach, namely least square support vector machine modeling optimized with coupled simulated annealing optimization technique, is proposed. Six models have been developed to predict saturated oil viscosity, which are designed in such a way that could predict saturated oil viscosity with every available PVT parameter. The constructed models are evaluated by carrying out extensive experimental saturated crude oil viscosity data from Iranian oil reservoirs, which were measured using a "Rolling Ball viscometer." To...
How particle shape affects the flow through granular materials
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 85, Issue 3 , 2012 ; 15393755 (ISSN) ; Ahmadi, M. M ; Mohammadi, S
2012
Abstract
Flow through the pores of granular materials has many instances in practice. Therefore, it is interesting to realize how some parameters, such as the shape of the particles affect the passing flow. Following the recent mathematical theory proposed by the authors, this paper deals with the issue of how tortuosity and permeability are influenced by the particle shape. Comparison of the results with the experimental data reveals the competency of the theory in predicting the impact of particle geometry
Calibration of forming limit diagrams using a modified Marciniak-Kuczynski model and an empirical law
, Article Materials and Design ; Volume 34 , Feb , 2012 , Pages 185-191 ; 02641275 (ISSN) ; Assempour, A ; Sharif University of Technology
2012
Abstract
The major problem in determining the forming limit diagram (FLD) with the Marciniak-Kuczynski (M-K) model is the necessity of an experimental point in order to find the initial inhomogeneity coefficient and calibrate the diagram. The purpose of the present work is to eliminate this requirement. To do this, the usual assumption of geometrical inhomogeneity has been replaced with material inhomogeneity and it has been shown that the sensitivity of the diagram to variations of the inhomogeneity factor is reduced greatly with the new assumption. Using this advantage and collecting enough experimental data for different materials, an empirical law in terms of sheet thickness has been proposed...
Optimization of a vanillin assay for determination of anthocyanins using D-optimal design
, Article Analytical Methods ; Volume 4, Issue 3 , Feb , 2012 , Pages 824-829 ; 17599660 (ISSN) ; Roohi, T ; Moghaddam, G ; Khoshayand, F ; Shahbazikhah, P ; Oveisi, M. R ; Hajimahmoodi, M ; Sharif University of Technology
Abstract
The vanillin assay is a spectrophotometric method for anthocyanin determination that is simple, quick and inexpensive. The method is preferred because of its high sensitivity, specificity and simplicity; however, the results of this test are influenced by several factors. Hence, a D-optimal experimental design approach was investigated to simultaneously, without loss of information, optimize five factors that influence the vanillin assay: acid normality, vanillin concentration, temperature, time and acid type. Further optimization with a D-optimal design and response surface analysis (RSM) showed that a second-order polynomial model fit the experimental data appropriately. The optimum...
A new calibration method for FLCs in the M-K frame-work
, Article Advanced Materials Research, 8 July 2011 through 11 July 2011 ; Volume 341-342 , July , 2012 , Pages 426-431 ; 10226680 (ISSN) ; 9783037852521 (ISBN) ; Assempour, A ; Sharif University of Technology
2012
Abstract
The main drawback of the method proposed by Marciniak and Kuczynski for prediction of the limit strains in sheet metal forming processes is requirement of an experimental point of the forming limit curve (FLC) in order to calibrate the curve. The purpose of this work is to introduce a new method to calibrate the FLC using the M-K model in which no experimental data is needed. To achieve this goal, many experimental FLCs were collected from the literature and the values of the initial inhomogeneity factors were determined for them with trial and error aproach. Using these data, an empirical law was developed to predict the value of inhomogeneity factor. The resultant curves show good...
A new hydration model in correlating the mean ionic activity coefficient and density of aqueous electrolyte solutions
, Article Journal of Dispersion Science and Technology ; Volume 31, Issue 5 , 2010 , Pages 641-649 ; 01932691 (ISSN) ; Taghikhani, V ; Vossoughi, M ; Sharif University of Technology
Abstract
In this article, a new hydration model has been proposed to study the phase behavior of aqueous electrolyte solutions. The proposed model distinguishes between an anion and cation in the electrolyte solution. The model has three adjustable parameters which can be obtained using the experimental data of the mean ionic activity coefficients for 113 electrolyte solutions. The results of the proposed model were compared with those of obtained from the Pitzer, the E-NRTL and the E-Wilson models. The results showed that the proposed model can accurately correlate the mean ionic activity coefficients of the aqueous electrolyte solutions than the other models. Also, the proposed model was used in...
Accurate prediction of viscosity of mixed oils
, Article Petroleum Science and Technology ; Volume 39, Issue 9-10 , 2021 , Pages 351-361 ; 10916466 (ISSN) ; Mehrizadeh, M ; Zand, N ; Najafi Marghmaleki, A ; Sharif University of Technology
Bellwether Publishing, Ltd
2021
Abstract
Viscosity of mixed oil is an important parameter which is required in transportation and production processes of mixed crude oils. There is no universal and general model for prediction of viscosity of mixed oils at different conditions. Hence, developing simple, accurate and general models for prediction of mixed oil viscosity is of great importance. In this work three computer based models named MLP-NN, PSO-RBF and Hybrid-ANFIS were developed for prediction of viscosity of mixed oils. A number of 513 experimental data covering wide ranges of influencing parameters were utilized to develop the models. The accuracy of predictions of the developed models was examined by using different...
Experimental and Modeling Study of Gas/WAG Injection at Near Miscible Condition in One of Iranian Oil Reservoirs
,
M.Sc. Thesis
Sharif University of Technology
;
Ghazanfari, Mohammad Hossein
(Supervisor)
;
Massihi, Mohsen
(Supervisor)
Abstract
Most of the Iranian oil reservoirs are reaching end of their natural production life, hence they are suitable candidates for EOR common processes like gas injection and WAG injection. Studies have shown that gas and WAG injection can be applied for optimal oil production. Past studies have been mainly on gas and WAG injection in immiscible or fully miscible conditions and there is a limited amount of data available on performance of these methods in near miscible conditions. Miscible injection is not feasible in old Iranian oil reservoirs due to their depleted pressure. Moreover injection in lower pressures is attractive from both economical and operational standpoints since this reduces the...
A viscoelastic constitutive model for compressible polymers based on logarithmic strain and its finite element implementation
, Article Finite Elements in Analysis and Design ; Volume 62 , 2012 , Pages 18-27 ; 0168874X (ISSN) ; Baghani, M ; Arghavani, J ; Sharif University of Technology
2012
Abstract
In this paper, employing the logarithmic (or Hencky) strain as a more physical measure of strain, the time-dependent response of compressible viscoelastic materials is investigated. In this regard, we present a phenomenological finite strain viscoelastic constitutive model, developed within the framework of irreversible thermodynamics with internal variables. The formulation is based on the multiplicative decomposition of the deformation gradient into elastic and viscoelastic parts, together with the use of the isotropic property of the Helmholtz strain energy function. Making use of a logarithmic mapping, we present an appropriate form of the proposed constitutive equations in the...
Experimental investigation and theoretical prediction of extrudate swell using conformational rheological models
, Article International Polymer Processing ; Volume 27, Issue 4 , 2012 , Pages 478-485 ; 0930777X (ISSN) ; Ahmad Ramazani, S. A ; Amoli, H. H ; Kamyabi, A ; Sharif University of Technology
Hanser
2012
Abstract
In this study the extrudate swell of polymer solutions is estimated using the microstructure of polymer molecules. When a flexible polymer chain goes through a narrow die shear stress exerting on the chain will cause the polymer chain to be stretched along the flow direction. After emerging from die all external stresses vanish immediately and the chains tend to recover their previous state due to elastic recovery. This phenomenon will results in a gradual increase in extrudate diameter and this is used as the key idea for estimating swell ratio. A Giesekus based conformational model was used in order to predict polymer chains microstructure everywhere in the domain. The resulting PDE set...
Dynamics and control of the flexible needles for percutaneous application: Partial feedback linearization method
, Article IEEE International Symposium on Industrial Electronics ; 2012 , Pages 831-834 ; 9781467301589 (ISBN) ; Jahed, M ; Sharif University of Technology
2012
Abstract
In this paper the dynamics and control of the underactuated flexible needle will be discussed. To evaluate the dynamics of the needle, the study uses Saint Venant-Kirchhoff and finite element method. The model is validated using the experimental data provided in the literature. It is also shown that using iterative decomposition of the dynamics equation the unactuated degree of freedom of the needle tip can be feedback linearized. The effect of the control signal exerted on the tip is projected via iterative decomposition of the dynamics equation. The efficiency of the approach will be next explored through some examples
Bubble size distribution in two-dimensional gas-solid fluidized beds
, Article Industrial and Engineering Chemistry Research ; Volume 51, Issue 18 , 2012 , Pages 6571-6579 ; 08885885 (ISSN) ; Molaei Dehkordi, A ; Banaei, M ; Deen, N. G ; Van Sint Annaland, M ; Kuipers, J. A. M ; Sharif University of Technology
2012
Abstract
In this article, the digital image analysis (DIA) technique has been used to study the bubble size and bubble size distribution evolution in a pseudo-two-dimensional gas-solid fluidized bed. In addition, a numerical discrete bubble model (DBM) based on the bubble-bubble interactions was developed and the model predictions were compared with the experimental data. The developed model can predict the bubble size and bubble size distribution through the bed height and the lateral distribution of bubbles. Comparison between model predictions and the result of DIA measurements shows that bubble breakage has a significant effect on the bubble size distribution especially at heights far from the...
Simultaneous analytical solution of the complete system of double-inlet pulse tube refrigerator
, Article Journal of Thermophysics and Heat Transfer ; Volume 26, Issue 2 , 2012 , Pages 337-344 ; 08878722 (ISSN) ; Saidi, M. H ; Ebrahimian, M ; Sharif University of Technology
2012
Abstract
Double-inlet pulse tube refrigerators are one of the most common types of cryocoolers. There are several advantages of double-inlet pulse tube refrigerators, such as not having moving parts, reliability, and long life. Double-inlet pulse tube refrigerators have been used in several applications such as cooling the semiconductors, infrared sensors, and astronomical detectors. In the recent decade, several research efforts have been performed to investigate double-inlet pulse tube refrigerators. Generally, most of them are experimental or numerical, and the recent literature survey shows there is not an analytical solution for the complete system of a double-inlet pulse tube refrigerator,...
The leaching kinetics of an oxide gold ore with iodide/iodine solutions
, Article Hydrometallurgy ; Volume 113-114 , 2012 , Pages 42-50 ; 0304386X (ISSN) ; Sharif University of Technology
2012
Abstract
Two types of gold ores were subjected to iodide/iodine leaching at room temperature. The effects of three factors, including ore type (a carbonaceous and an oxide gold ores), iodide/iodine concentration, and the presence of oxygen in solution on gold leaching performance were investigated. The carbonaceous ore showed only 20% gold extraction, since gold-iodide complexes readily adsorb on organic matter. In contrast, gold extraction from the oxide ore in a solution containing 20 g/L iodide and 4 g/L iodine reached 77% in 6 h and 89% in 24 h. With iodate as the oxidant, no gold could be leached in 48 h. When the iodate was partially converted to iodine by adding HCl to the solution, gold...
Kinetics of pressure oxidative leaching of molybdenite concentrate by nitric acid
, Article Hydrometallurgy ; Volume 111-112, Issue 1 , January , 2012 , Pages 52-57 ; 0304386X (ISSN) ; Yoozbashizadeh, H ; Mozammel, M ; Sadrnezhaad, S. K ; Sharif University of Technology
2012
Abstract
The current study was carried out to investigate the kinetics of reactions for the pressure oxidative leaching of a molybdenite concentrate in less than one hour. The effects of oxygen pressure, stirring speed, pulp density, acid concentration and temperature on the leaching rate of the molybdenum were studied. It was found that about 85% of molybdenite was oxidized to molybdic oxide precipitate with remaining molybdenum dissolved in the leaching liquor. Analysis of experimental data showed that the reaction is chemically controlled with activation energy of 68.8 kJ/mol. Furthermore SEM images showed no significant boundary diffusion layer and it was noted that the molybdic oxide...
A mixture of modular structures to describe human motor planning level: A new perspective based on motor decomposition
, Article 2011 18th Iranian Conference of Biomedical Engineering, ICBME 2011 ; 2011 , Pages 199-204 ; 9781467310055 (ISBN) ; Andani, M. E ; Fattah, A ; Parnianpour, M ; Sharif University of Technology
Abstract
A modular hierarchical structure is developed to describe human movement planning level. The modular feature of the proposed model enables it to generalize planning a task. The movements are planned based on decomposing a task into its corresponding subtasks (motion phases). There is a module responsible for one condition. The final plan is constructed using soft computing of the plans proposed by different modules. Each module estimates the kinematics of the joints at the end of each subtask; we call them kinematic estimator modules (KEMs). A timing module estimates the duration of motion and a gating module determines the responsibility of each KEM under different conditions. To evaluate...
Effect of step geometry on the performance of the airlift pump
, Article International Journal of Fluid Mechanics Research ; Volume 38, Issue 5 , 2011 , Pages 387-408 ; 10642277 (ISSN) ; Karimi, A ; Saidi, M. H ; Sharif University of Technology
2011
Abstract
Airlift pumps are devices which are widely used in industrial applications. Parameters such as diameter of the pipe, tapering angle of the upriser pipe, submergence ratio, the gas flow rate, bubble diameter, and inlet gas pressure affect the performance of this type of pumps. In this research, the performances of airlift pumps with a vertical upriser length of 914 mm and initial diameters of 6 and 8 mm and various heights for steps, range 0:2 to 0:9 m, in submergence ratio of 0:6 are investigated numerically. The results show the improvement in the performance of step airlift pump (SALP) in comparison with ordinary type (OALP). Considering the effect of height of steps and secondary pipe...
Matrix analysis of nonlinear trusses using Prandtl-2 neural networks
, Article Journal of Sound and Vibration ; Volume 330, Issue 20 , 2011 , Pages 4813-4826 ; 0022460X (ISSN) ; Farrokh, M ; Sharif University of Technology
2011
Abstract
A new method, based on the concepts of matrix analysis as well as the learning capabilities of neural networks, for the analysis of nonlinear trusses under dynamic loading is presented. The method can be applied to static trusses too. While there have been attempts in the past to use neural networks to identify and model different structures based on data measured on structural response directly, the main feature and advantage of this new method is in its capability to model a nonlinear truss by assembling the data collected on the response of its members. The basics of the method are: (1) for each truss member, a neural network is trained to learn and simulate its loadresponse behavior, (2)...
Calculating leakage inductances of pancake windings in dry-type traction transformers
, Article ECTI-CON 2011 - 8th Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand - Conference 2011, 17 May 2011 through 19 May 2011, Khon Kaen ; 2011 , Pages 808-811 ; 9781457704246 (ISBN) ; Vakilian, M ; Faiz, J ; Bigdeli, M ; Sharif University of Technology
2011
Abstract
Calculating leakage inductances between windings of multi-winding Traction transformers is one of the most important schemes in design procedure. In this paper, analytical and finite element methods (FEM) have been introduced for electromagnetic modeling of traction transformers with four pancake split windings. Using these models, the leakage inductances between the split windings are calculated and the models have been validated with the help of experimental data gathered from a typical 4000kVA cast-resin dry-type transformer. Some reformations are employed to improve the FEM results and effects of these reformations on accuracy of the model are studied. Employing the validated models, the...
Modeling of osmotic pressure of aqueous poly(ethylene glycol) solutions using the artificial neural network and free volume flory huggins model
, Article Journal of Dispersion Science and Technology ; Volume 32, Issue 7 , 2011 , Pages 1054-1059 ; 01932691 (ISSN) ; Pazuki, G. R ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
2011
Abstract
In this work, the modified Flory-Huggins coupled with the free-volume concept and the artificial neural network models were used to obtain the osmotic pressure of aqueous poly(ethylene glycol) solutions. In the artificial neural network, the osmotic pressure of aqueous poly(ethylene glycol) solutions depends on temperature, molecular weight and the mole fractions of poly(ethylene glycol) in aqueous solution. The network topology is optimized and the (3-1-1) architecture is found using optimization of an objective function with batch back propagation (BBP) method for 134 experimental data points. The results obtained from the neural network in obtaining of the osmotic pressure of aqueous...