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The nanofibrous PAN-PANi scaffold as an efficient substrate for skeletal muscle differentiation using satellite cells
, Article Bioprocess and Biosystems Engineering ; Volume 39, Issue 7 , 2016 , Pages 1163-1172 ; 16157591 (ISSN) ; Mahmoudifard, M ; Mohamadyar Toupkanlou, F ; Dodel, M ; Hajarizadeh, A ; Adabi, M ; Soleimani, M ; Sharif University of Technology
Springer Verlag
Abstract
Among polymers, polyaniline (PANi) has been introduced as a good candidate for muscle regeneration due to high conductivity and also biocompatibility. Herein, for the first time, we report the use of electrospun nanofibrous membrane of PAN-PANi as efficient scaffold for muscle regeneration. The prepared PAN-PANi electrospun nanofibrous membrane was characterized by scanning electron microscopy (SEM), Attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) and tensile examination. The softer scaffolds of non-composite electrospun nanofibrous PAN govern a higher rate of cell growth in spite of lower differentiation value. On the other hand, PAN-PANi electrospun...
Flow and performance characteristics of twin-entry radial turbine under full and extreme partial admission conditions
, Article Archive of Applied Mechanics ; Volume 79, Issue 12 , 2009 , Pages 1127-1143 ; 09391533 (ISSN) ; Rad, M ; Shahhosseini, M. R ; Sharif University of Technology
Abstract
This paper presents numerical and experimental investigation of the performance and internal flow field characteristics of twin-entry radial inflow turbines at full and extreme partial admission conditions. The turbine is tested on a turbocharger test facility, which was developed for small and medium size turbochargers. Experimental results show that the lowest efficiency corresponds to extreme conditions. Therefore, flow field analyzing is employed to consider these conditions. The flow pattern in the volute and impeller of a twin-entry turbine is analyzed using an in-house fully three-dimensional viscous flow solver. The computational performance results are compared with the experimental...
Optimal reactive power dispatch using the concept of dynamic VAR source value
, Article 2009 IEEE Power and Energy Society General Meeting, PES '09, 26 July 2009 through 30 July 2009, Calgary, AB ; 2009 ; 9781424442416 (ISBN) ; Parniani, M ; Sharif University of Technology
Abstract
Voltage stability is the ability of a power system to maintain acceptable voltages at all buses in the system under normal conditions and after being subjected to a disturbance. This paper employs the management of reactive power generation to improve the voltage stability margin (VSM), in the framework of optimal reactive power dispatch (ORD) problem. Scheduling of VAR sources is performed using the concept of relative value of VAR sources. The proposed methodology has been tested on the IEEE 14-bus test system. Simulation results show that after the optimal reactive power scheduling, VSM of the systems is increased considerably. In addition, it is observed that reactive power reserve is...
Risk based maintenance optimization of overhead distribution networks utilizing priority based dynamic programming
, Article 2009 IEEE Power and Energy Society General Meeting, PES '09, 26 July 2009 through 30 July 2009, Calgary, AB ; 2009 ; 9781424442416 (ISBN) ; Fotuhi Firuzabad, M ; Abiri Jahromi, A ; Sharif University of Technology
Abstract
This paper presents a priority based dynamic programming approach for long term maintenance scheduling of overhead distribution networks. The proposed approach is based on risk management approach and utilizes the model of decoupled risk factors. Two heuristic factors are defined and utilized in order to establish a maintenance priority list and to curtail the dynamic programming search space. The proposed methodology yields a significant computational saving compare to the previously reported dynamic programming. Risk management approach enables the asset managers to consider the actual condition of electrical equipments and expected consequence of their failures. Furthermore, the decoupled...
Flow field analysis around the ship fin stabilizer including free surface
, Article Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 31 May 2009 through 5 June 2009, Honolulu, HI ; Volume 4, Issue PART A , 2009 , Pages 603-608 ; 9780791843444 (ISBN) ; Ghassemi, H ; Ghadimi, P ; Ommani, B ; Sharif University of Technology
Abstract
Fin stabilizers are very important device for controlling the ship roll motion against the external moments due to wave. This paper presents numerical results for flow field simulation and the hydrodynamic performance of fin stabilizer attached to a ship hull with free surface effects. Combination of CFD and RANS method has been used for this study. The fin is nonrectangular NACA0015 profile section with a finite aspect ratio. The numerical results include pressure distributions and flow field around the fin which are used to calculate lift coefficients and free surface elevation as the main interest. Some results are compared with available experimental and numerical data in literature and...
Application of the splitting approach to solve population balance equations in chemical processes
, Article Chemical Engineering and Technology ; Volume 32, Issue 12 , 2009 , Pages 1894-1900 ; 09307516 (ISSN) ; Baghaei, A ; Sarrafi, A ; Sharif University of Technology
Abstract
Different processes in chemical industries deal with particles and multiphase flow. In such processes, particle or bubble size distribution (PSD) influences the final product quality and also process design. On the other hand, solutions to the dominant hydrodynamic and thermo-kinetic equations ignoring these distributions will make it impossible to accurately simulate these processes. Solutions to population balance equations (PBE's) are needed to attain the PSD. One of the most common methods for the solution of a PBE is the classes method (CM). However, as this method requires a large number of classes to give a reasonable result, it needs a huge amount of calculations and time. To...
A new semi-analytical modeling of steam-assisted gravity drainage in heavy oil reservoirs
, Article Journal of Petroleum Science and Engineering ; Volume 69, Issue 3-4 , 2009 , Pages 261-270 ; 09204105 (ISSN) ; Pishvaie, M. R ; Jabbari, H ; Sharif University of Technology
Abstract
Thermal recovery by steam injection has proven to be an effective means of recovering heavy oil. Forecasts of reservoir response to the application of steam are necessary before starting a steam drive project. Thermal numerical models are available to provide forecasts. However, these models are expensive and consume a great deal of computer time. An alternative to numerical modeling is to use a semi-analytical model. The objective of the current study was to investigate thermal applications of horizontal wells for displacement and gravity drainage processes using analytical modeling as well as reservoir simulation. The main novelties presented in the paper are: a) the transient temperature...
Effect of CO2 and natural surfactant of crude oil on the dynamic interfacial tensions during carbonated water flooding: experimental and modeling investigation
, Article Journal of Petroleum Science and Engineering ; Volume 159 , 2017 , Pages 58-67 ; 09204105 (ISSN) ; Riazi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
Carbonated water has been recently proposed as an enhanced oil recovery method for crude oil reservoirs. Interfacial tension (IFT) plays a crucial rule on the displacement of trapped oil ganglia in the porous media. This investigation is designed to systematically assess the dynamic interfacial tension (DIFT) of two different types of crude oils with carbonated water (CW). In addition, the measured experimental data were applied into specified models. The DIFT behavior of acidic and non-acidic crude oil samples/CW and deionized water (DW) are also compared to find the effect of dissolved carbon dioxide in water on IFT. At the next stage, DIFT of all the results were used through three...
Investigating the effect of hybrid silica nanoparticles-copolymer on increasing oil recovery in a three dimensional porous media
, Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3466-3475 ; 10263098 (ISSN) ; Ramazani, A. S. A ; Hekmatzadeh, M ; Sharif University of Technology
Abstract
In this work, hybrid of silica nanoparticles (NPs) with sulfonated copolymer has been prepared in order to improve the copolymer properties for Enhanced Oil Recovery (EOR). Some tests are done to find the effectiveness of injecting fluid on Recovery Factor (RF), such as Contact Angle (CA), interfacial tension (IFT), inherent viscosity, and eventually Micro-Model (MM) flooding. In CA test, wettability alteration from Oil-Wet (OW) to Water-Wet (WW) is reached by sedimentation and adsorption of NPs on the rock slice. In addition, IFT reduction is obtained by increasing the NaCl concentration. The viscosity change is investigated for the hybrid and copolymer under simulated high-temperature oil...
Physical, morphological, and biological studies on PLA/nHA composite nanofibrous webs containing equisetum arvense herbal extract for bone tissue engineering
, Article Journal of Applied Polymer Science ; Volume 134, Issue 39 , 2017 ; 00218995 (ISSN) ; Jafari, S. H ; Zahedi, P ; Bagheri, R ; Hajiaghaee, R ; Sharif University of Technology
Abstract
A series of herbal extract incorporated into poly(lactic acid) (PLA) composite nanofibrous scaffolds were successfully prepared by using electrospinning technique. Equisetum arvense extract (EE) and nanohydroxyapatite (nHA) in different quantities were loaded into PLA solution to fabricate composite nanofibrous webs under various electrospinning conditions. Uniform nanofibers were obtained with an average diameter of 157 ± 47 nm in the case of those containing the herbal extract. Characterization of the webs was carried out by means of Fourier transform infrared (FTIR) spectroscopy, field emission-scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and...
Review on different experimental techniques developed for recording force-deformation behaviour of soft tissues; with a view to surgery simulation applications
, Article Journal of Medical Engineering and Technology ; Volume 41, Issue 4 , 2017 , Pages 257-274 ; 03091902 (ISSN) ; Rostami, M ; Farahmand, F ; Sharif University of Technology
Abstract
Different experimental techniques which have been developed to obtain data related to force-deformation behaviour of soft tissues play an important role in realistically simulating surgery processes as well as medical diagnoses and minimally invasive procedures. Indeed, an adequate quantitative description of soft-tissue-mechanical-behaviour requires high-quality experimental data to be obtained and analysed. In this review article we will first scan the motivations and basic technical issues on surgery simulation. Then, we will concentrate on different experimental techniques developed for recording force-deformation (stress-strain) behaviour of soft tissues with focussing on the in-vivo...
A comparison between monitoring and analysis of Taleghan rockfill dam during construction
, Article Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering: The Academia and Practice of Geotechnical Engineering, 5 October 2009 through 9 October 2009 ; Volume 3 , 2009 , Pages 2088-2091 ; 9781607500315 (ISBN) ; Faghihi, D ; Sharif University of Technology
Abstract
The construction of 103 m high Taleghan rockfill dam in Iran has recently been completed and reservoir impounding has also recently been started. The behavior of different sections of the dam have been monitored during construction using various devices such as settlement gauges, earth pressure cells and pore pressure piezometers. A comprehensive finite element study has been implemented in this regard as well to study the behavior of Taleghan rockfill dam during construction with consideration of unsaturated behavior of the materials of the dam. A 2D coupled analysis was performed using ABAQUS software. The behavior of the materials of the core and rockfill were assumed to follow Modified...
Application of damage spectra as seismic intensity measures in endurance time method for steel moment-resisting frames
, Article Scientia Iranica ; Volume 24, Issue 1 , 2017 , Pages 53-64 ; 10263098 (ISSN) ; Estekanchi, H. E ; Sharif University of Technology
Abstract
In seismic resistant design of moment frames, the structure behavior under earthquakes has to be examined considering various damage criteria. Damage indices can be estimated by Endurance Time (ET) method with minimum computational effort. The quality of this estimation can be improved in different ways. In this paper, the graphs of a certain damage index versus natural period of the structure, called damage spectra, are produced applying intensifying ET records and scaled Ground Motions (GM). Then, the excitation duration of ET acceleration functions (target time) is modified in order to reach acceptable consistency between ET and GM damage spectra. Moreover, various damage indices of a...
A sequential implicit discrete fracture model for three-dimensional coupled flow-geomechanics problems in naturally fractured porous media
, Article Journal of Petroleum Science and Engineering ; Volume 150 , 2017 , Pages 312-322 ; 09204105 (ISSN) ; Shamloo, A ; Dezfuli, A. D ; Sharif University of Technology
Abstract
A sequential implicit numerical method based on discrete-fracture model and the Galerkin Finite Element method, for time-dependent coupled fluid flow and geomechanics problems in fractured subsurface formations is presented. Discrete-fracture model has been used to explicitly represent the fracture network inside porous media. The Galerkin Finite Element method with adaptive unstructured gridding is implemented to numerically solve the spatially three-dimensional and time-dependent problem. The presented method is validated with previously obtained solutions. Two problems are numerically solved by applying the presented methodology in a three-dimensional fractured petroleum reservoir under...
Power sector development in Iran: a retrospective optimization approach
, Article Energy ; Volume 140 , 2017 , Pages 330-339 ; 03605442 (ISSN) ; Aryanpur, V ; Sharif University of Technology
Abstract
This paper provides an overview of the power sector development in Iran for the period 1984–2014. A retrospective optimization approach is applied to assess economic and environmental benefits that would have been achieved through appropriate long-term planning. MESSAGE, a systems engineering optimization model, is used for this analysis. Two alternative scenarios are defined to explore the impact of supply- and demand-side strategies on the power generation mix, fuel consumption and CO2 emissions. The focus on the past choice of energy scenarios provides some insights for future scenario design. The results of the cost-optimal scenarios with international fuel prices are compared with the...
Investigating the effects of rock and fluid properties in Iranian carbonate matrix acidizing during pre-flush stage
, Article Journal of Petroleum Science and Engineering ; Volume 166 , 2018 , Pages 121-130 ; 09204105 (ISSN) ; Shirazi, M. M ; Ayatollahi, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Acidizing of carbonate oil-wet rocks saturated with oil and saline formation water is subjected failure in some cases due to acid-induced damage such as sludge and emulsion formations. This condition may also lead to mineral precipitation, oil film barrier between acid and rock and diversion chemical malfunctions. Therefore, pre-flush process has been proposed as one of the most efficient stage for oil-wells matrix acidizing to reduce these challenges significantly. Besides, the pre-flush stage would result in more clean rock as the reservoir fluids are pushed back from the near wellbore regions, restoring rock wettability to more water wet state, preventing direct acid-oil contact and...
Relative permeabilities hysteresis for oil/water, gas/water and gas/oil systems in mixed-wet rocks
, Article Journal of Petroleum Science and Engineering ; Volume 161 , February , 2018 , Pages 559-581 ; 09204105 (ISSN) ; Sohrabi, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Accurate determination of relative permeability (kr) curves and their hysteresis is needed for reliable prediction of the performance of oil and gas reservoirs. A few options (e.g., Carlson, Killough and Jargon models) are available in commercial reservoir simulators to account for hysteresis in kr curves under two-phase flow. Two-phase kr curves are also needed for estimating kr hysteresis under three-phase flow during water-alternating-gas (WAG) injection. Although, most oil reservoirs are mixed-wet, the existing hysteresis predictive approaches have been developed based on water-wet conditions. Experimentally measured data are needed to assess the performance of these methodologies under...
On a various soft computing algorithms for reconstruction of the neutron noise source in the nuclear reactor cores
, Article Annals of Nuclear Energy ; Volume 114 , 2018 , Pages 19-31 ; 03064549 (ISSN) ; Esmaili Paeen Afrakoti, I ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This paper presents a comparative study of various soft computing algorithms for reconstruction of neutron noise sources in the nuclear reactor cores. To this end, the computational code for reconstruction of neutron noise source is developed based on the Adaptive Neuro-Fuzzy Inference System (ANFIS), Decision Tree (DT), Radial Basis Function (RBF) and Support Vector Machine (SVM) algorithms. Neutron noise source reconstruction process using the developed computational code consists of three stages of training, testing and validation. The information of neutron noise sources and induced neutron noise distributions are used as output and input data of training stage, respectively. As input...
Controlling differentiation of stem cells for developing personalized organ-on-chip platforms
, Article Advanced Healthcare Materials ; Volume 7, Issue 2 , 2018 ; 21922640 (ISSN) ; Jafari, P ; Sheikh Hassani, M ; Heidary Araghi, B ; Mohammadi, M. H ; Ghafari, A. M ; Hassanpour Tamrin, S ; Pezeshgi Modarres, H ; Rezaei Kolahchi, A ; Ahadian, S ; Sanati Nezhad, A ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Organ-on-chip (OOC) platforms have attracted attentions of pharmaceutical companies as powerful tools for screening of existing drugs and development of new drug candidates. OOCs have primarily used human cell lines or primary cells to develop biomimetic tissue models. However, the ability of human stem cells in unlimited self-renewal and differentiation into multiple lineages has made them attractive for OOCs. The microfluidic technology has enabled precise control of stem cell differentiation using soluble factors, biophysical cues, and electromagnetic signals. This study discusses different tissue- and organ-on-chip platforms (i.e., skin, brain, blood–brain barrier, bone marrow, heart,...
Insight into the behavior of colloidal gas aphron (CGA) fluids at elevated pressures: an experimental study
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 537 , January , 2018 , Pages 250-258 ; 09277757 (ISSN) ; Kazemzadeh, E ; Kamari, E ; Ghazanfari, M. H ; Soleymani, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Recently, colloidal gas aphron (CGA) fluids technology has been employed to drill depleted oil and gas reservoirs. Almost all reported experience on CGA fluids were conducted at ambient conditions, and little attention has been paid on the behavior of CGAs at high pressures which is more close to real conditions. In this study, high pressure experiments were conducted by using High Pressure Microscope cell to visualize/monitor the behavior of CGAs at elevated pressures. Single bubble behavior and bubble size distribution (BSD) of CGAs were investigated under different scenarios of pressure change. Results of experiments revealed that BSD of CGAs is controlled by the path of pressure changes,...