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concentration--process
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Elastic solids with high concentration of arbitrarily oriented multiphase particles
, Article Acta Mechanica ; Volume 189, Issue 3-4 , 2007 , Pages 125-139 ; 00015970 (ISSN) ; Shodja, H. M ; Sharif University of Technology
Springer-Verlag Wien
2007
Abstract
The effective properties of elastic solids are strongly linked to their interacting micro-constituent phases. For materials containing dilute distributions of single-phase inhomogeneities, the overall behavior can be estimated in a straightforward manner. But in the non-dilute case, due to the complex inter-particle and particle-matrix interactions the treatment is rather involved. When the particles are heterogeneous, not only become the mentioned interactions more complex, but must properly account for the intra-particle interactions as well. The present work addresses an analytical approach to determine the overall moduli of elastic solids containing random distributions of arbitrarily...
Evaluation of bioactivity and biocompatibility of silk fibroin/TiO2 nanocomposite
, Article Journal of Medical and Biological Engineering ; Volume 38, Issue 1 , February , 2018 , Pages 99-105 ; 16090985 (ISSN) ; Madaah Hosseini, H. R ; Taromi, N ; Arasteh, S ; Kazemnejad, S ; Samadi Kuchaksaraei, A ; Sharif University of Technology
Springer Berlin Heidelberg
2018
Abstract
Biodegradable polymer/bioceramic nanocomposites are osteoconductive and can accelerate healing of bone tissue. In this research, silk fibroin (SF)/titanium dioxide (TiO2) nanocomposites were synthesized using different concentrations of TiO2 nanoparticles (0, 5, 10, 15 and 20 wt%). The SF/TiO2 nanocomposites were studied in terms of bioactivity and biocompatibility. The in vitro assessment of osteoblasts compatibility indicated that SF inclusion rendered nanocomposite biocompatible whereas presence of TiO2 nanoparticles allowed the cells to adhere and grow on nanocomposite surface and enhanced the bioactivity of the composite. © 2017, Taiwanese Society of Biomedical Engineering
Analysis of six-phase induction motor with distributed and concentrated windings by using the winding function method
, Article 23rd International Conference on Electrical Machines, ICEM 2018, 3 September 2018 through 6 September 2018 ; 2018 , Pages 2423-2429 ; 9781538624777 (ISBN) ; Vaschetto, S ; Tahami, F ; Capolino, G. A ; Henao, H ; Nasiri Gheidari, Z ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Multi-phase induction motors feature a high fault-tolerance capability that makes them suitable for safety critical applications. On the other hand, concentrated winding is more fault-tolerant than conventional distributed winding. Therefore, the general idea is to use concentrated winding on the six-phase induction motor to gain more fault-tolerance capacity. Using concentrated winding has several advantages over distributed one, but it has the disadvantage of higher distortion of air gap flux density, which affects the motor performance significantly. In this paper, some concentrated windings are studied analytically by using the winding function analysis, and the layout with better...
HTS YBCO resonator configuration with a coplanar optimized flux concentrator strongly coupled to RF squid
, Article IEEE Transactions on Applied Superconductivity ; Volume 28, Issue 4 , 2018 ; 10518223 (ISSN) ; Shanehsazzadeh, F ; Mazdouri, B ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
We developed a novel magnetic coupling module, formed of a monolayer superconducting flux concentrator that is integrated with a coplanar resonator, strongly coupled to high-temperature superconducting radio frequency superconducting quantum interference device (SQUID). Three types of resonators, including a long stripline resonator between the input loop and the pick-up loop of the flux concentrator, a complementary split ring resonator, and a spiral shape inside the input loop, are explored. The resonance quality factor of different patterns of these three types of the resonators, as well as their coupling to the SQUID, is evaluated using finite-element-method simulations. Several readout...
A series stacked IGBT switch based on a concentrated clamp mode snubber for pulsed power applications
, Article IEEE Transactions on Power Electronics ; Volume 34, Issue 10 , 2019 , Pages 9573-9584 ; 08858993 (ISSN) ; Mohsenzade, S ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Clamp mode snubbers are very well suited for the series structure of the insulated-gate bipolar transistors (IGBTs) in pulsed power applications. They properly meet the necessities expected from them such as the fast operating of the series IGBTs since they have no effect on the gate side. In addition, they can provide safe voltage condition for the IGBTs in short circuit faults, which are very probable in pulsed applications. The clamp mode snubber can perform its voltage balancing task whenever the power capacity of the snubber can support the injected powers due to the voltage unbalancing factors. This paper initially introduces the main factors injecting power to the snubbers. Then, it...
Improvement of concentrated winding layouts for six-phase squirrel cage induction motors
, Article IEEE Transactions on Energy Conversion ; Volume 35, Issue 4 , 2020 , Pages 1727-1735 ; Tahami, F ; Capolino, G. A ; Vaschetto, S ; Nasiri Gheidari, Z ; Henao, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The fault-tolerant capability is a prerequisite for electrical safety-critical applications. In this regard, multi-phase induction motors are well-known actuators used to provide this feature. Compared to conventional three-phase machines with distributed windings, induction machines having concentrated windings could be more fault-tolerant because of increasing the number of phases. In addition, concentrated windings have shorter end-winding and less required copper weight which makes it a lower cost solution compared to distributed windings. However, concentrated windings adversely increase the distortion of the air gap flux density which affects motor performances. In this paper, a...
Improved design of an outer rotor six-phase induction motor with variable turn pseudo-concentrated windings
, Article IEEE Transactions on Energy Conversion ; Volume 37, Issue 2 , 2022 , Pages 1020-1029 ; 08858969 (ISSN) ; Tahami, F ; Capolino, G. A ; Nasiri Gheidari, Z ; Henao, H ; Sahebazamani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
In this paper, a novel six-phase outer rotor induction motor equipped with pseudo-concentrated windings is introduced as a robust, reliable, and low-cost solution. Multiple aspects of the proposed motor structure have been investigated such as a design algorithm and an analytical modeling based on the modified winding function considering the skew effect. The effect of using variable number of turns for the coils has been examined on the pseudo-concentrated windings. An appropriate optimization problem has been also defined to maximize the power factor and efficiency and to minimize the output torque ripple. The designed motor has been fabricated to verify the accuracy of the design...
Optical and thermal analysis of a parabolic trough solar collector for production of thermal energy in different climates in Iran with comparison between the conventional nanofluids
, Article Journal of Cleaner Production ; Volume 175 , 2018 , Pages 294-313 ; 09596526 (ISSN) ; Mehrpooya, M ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Optical and thermal analysis of the most well-known solar concentrator system; parabolic trough collector (PTC) are investigated and analyzed. To evaluate performance of the PTC, four cities of Iran with different weather conditions are chosen as case studies. Effective parameters such as concentration ratio, incident angle correction factor, collector mass flow rate are considered. The main objective of this work is evaluation of the solar energy potential using PTC in under consideration cities with different climates. Numerical modeling of the analysis is done using MATLAB software. Simulation results shows that Shiraz, with an average annual thermal efficiency of 13.91% and annual useful...
Biodegradation of styrene laden waste gas stream using a compost-based biofilter
, Article Chemosphere ; Volume 60, Issue 3 , 2005 , Pages 434-439 ; 00456535 (ISSN) ; Torkian, A ; Bina, B ; Poormoghaddas, H ; Kalantary, A ; Sharif University of Technology
Elsevier Ltd
2005
Abstract
Biological treatment of waste gas styrene vapor was investigated in a three-stage bench-scale biofilter. Yard waste compost mixed with shredded hard plastics in a 25:75 v/v ratio of plastics:compost was inoculated with thickened municipal activated sludge. Microbial acclimation to styrene was achieved by exposing the system to an inlet concentration (CIn) of 0.25 g m -3 styrene and an empty bed retention time (EBRT) of 360 s for 30 days. Under steady-state conditions, maximum elimination capacity (EC) obtained was 45 g m-3 h-1 at a loading rate (L) of 60 g m -3 h-1 (CIn of 2 g m-3 and EBRT of 120 s). Reduction of retention time adversely impacted the performance resulting in the maximum EC...
Optimal design of solar concentrator in multi-energy hybrid systems based on minimum exergy destruction
, Article Renewable Energy ; Volume 190 , 2022 , Pages 78-93 ; 09601481 (ISSN) ; Saboohi, Y ; Fathi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The paper presents a systematic approach to designing an imaging dish for a concentrator photovoltaic (CPV) system to minimize exergy destruction. The designed CPV system uniformly distributes light rays on the receiver (TPV/multi-junction PV) to enhance the conversion technology efficiency and lifetime. To this end, a parametric dish is designed using imaging optics and the numerical solution of a differential equation. Afterward, a Monte Carlo simulation is used to estimate the output energy and exergy of the CPV system with the parametric dish. Finally, an optimization algorithm finds the optimal design parameters to minimize the system's exergy destruction. The optimal design leads to a...
Gas absorption enhancement in hollow fiber membrane contactors using nanofluids: Modeling and simulation
, Article Chemical Engineering and Processing: Process Intensification ; Volume 119 , 2017 , Pages 7-15 ; 02552701 (ISSN) ; Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In this article, a comprehensive 2D mathematical model has been developed to simulate process intensification of carbon dioxide absorption in the presence of nanoparticles in hollow fiber membrane contactors (HFMCs). The influences of nanoparticle were taken into account considering Brownian motion and Grazing effect as dominant phenomena of mass-transfer enhancement in nanofluids. The obtained simulation results were validated against experimental data reported in the literature and excellent agreement was obtained. It was found that by adding 0.05 wt % silica nanoparticles, the absorption rate could be enhanced by 16%, while the corresponding value is 32% for CNT nanoparticles. High...
A study on mutual interaction between atomistic and macroscopic phenomena during electrochemical processes using FD-KMC model: Application to CV test in simple copper sulfate bath
, Article Journal of Electroanalytical Chemistry ; Volume 592, Issue 1 , 2006 , Pages 95-102 ; 15726657 (ISSN) ; Sharif University of Technology
Elsevier
2006
Abstract
A multiscale FD-KMC model has been developed to simulate the cyclic voltammetry test of a copper electrode in simple copper sulfate bath. In this coupled model, the FD code provides the cupric ion concentration on OHP for KMC code, while the KMC code provides the electrochemical properties of the copper electrode (surface activity and rate constants of redox reactions) as an input data for FD code. The changes in the electrode properties due to the atomistic phenomena (deposition dissolution and surface diffusion) have been studied for the present potentiodynamic system. The results showed that the CV process consists of some distinct stages, so that the electrode exhibits a specific...
A transient model of vanadium redox flow battery
, Article Mechanics and Industry ; Volume 17, Issue 4 , 2016 ; 22577777 (ISSN) ; Elyasi, S ; Sharif University of Technology
EDP Sciences
2016
Abstract
It has been attempted to gain a new viewpoint in transient cell modeling of vanadium redox flow battery. This has been achieved by considering electrochemical relations along with conceptual electrical circuit of this kind of battery. The redox flow battery is one of the best rechargeable batteries because of its capability to average loads and output power sources. A model of transient behavior is presented in this paper. The transient features are considered as the most remarkable characteristics of the battery. The chemical reactions, fluid flow, and electrical circuit of the structure govern the dynamics. The transient behavior of the redox flow battery based on chemical reactions is...
Nanofiltration process on dye removal from simulated textile wastewater
, Article International Journal of Environmental Science and Technology ; Volume 5, Issue 3 , 2008 , Pages 401-408 ; 17351472 (ISSN) ; Mirzayee, R ; Nasseri, S ; Borghei, M ; Gholami, M ; Torabifar, B ; Sharif University of Technology
CEERS
2008
Abstract
Dyestuffs removal from industrial wastewater requires special advanced technologies, since dyes are usually difficult to remove by biological methods. In this study nanofiltration process was used for removal of different dyestuffs from solutions. The rate of dye removal by spiral wound nanofiltration membrane in film thin composite MWCO=90 Dalton, was evaluated for four classes of dyes acidic, disperse, reactive and direct in red and blue dyes medium. Dye absorbance was measured by spectrophotometric method (2120 Standard Method 1998). Effects of feed concentration, pressure and total dissolved solids concentration were also studied. Results showed that increasing dye concentration lead to...
Algorithmic analysis of qualitative and quantitative termination problems for affine probabilistic programs
, Article 43rd Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, 20 January 2016 through 22 January 2016 ; Volume 20-22-January-2016 , 2016 , Pages 327-342 ; 07308566 (ISSN) ; 9781450335492 (ISBN) ; Fu, H ; Novotný, P ; Hasheminezhad, R ; Majumdar, R ; Bodik, R ; Association for Computing Machinery (ACM) SIGPLAN ; Sharif University of Technology
Association for Computing Machinery
Abstract
In this paper, we consider termination of probabilistic programs with real-valued variables. The questions concerned are: (a) qualitative ones that ask (i) whether the program terminates with probability 1 (almost-sure termination) and (ii) whether the expected termination time is finite (finite termination); (b) quantitative ones that ask (i) to approximate the expected termination time (expectation problem) and (ii) to compute a bound B such that the probability to terminate after B steps decreases exponentially (concentration problem). To solve these questions, we utilize the notion of ranking supermartingales which is a powerful approach for proving termination of probabilistic programs....
Algorithmic analysis of qualitative and quantitative termination problems for affine probabilistic programs
, Article ACM SIGPLAN Notices ; Volume 51, Issue 1 , 2016 , Pages 327-342 ; 15232867 (ISSN) ; Fu, H ; Novotný, P ; Hasheminezhad, R ; Sharif University of Technology
Association for Computing Machinery
Abstract
In this paper, we consider termination of probabilistic programs with real-valued variables. The questions concerned are: (a) qualitative ones that ask (i) whether the program terminates with probability 1 (almost-sure termination) and (ii) whether the expected termination time is finite (finite termination); (b) quantitative ones that ask (i) to approximate the expected termination time (expectation problem) and (ii) to compute a bound B such that the probability to terminate after B steps decreases exponentially (concentration problem). To solve these questions, we utilize the notion of ranking supermartingales which is a powerful approach for proving termination of probabilistic programs....
The effect of variable catalyst loading in electrodes on PEM fuel cell performance
, Article 3rd International Conference on Fuel Cell Science, Engineering, and Technology, 2005, Ypsilanti, MI, 23 May 2005 through 25 May 2005 ; 2005 , Pages 145-152 ; 0791837645 (ISBN); 9780791837641 (ISBN) ; Farhanieh, B ; Sharif University of Technology
American Society of Mechanical Engineers
2005
Abstract
Catalyst layers are one the important parts of the PEM fuel cells as they are the main place for electrochemical reaction taking place in anode and cathode of the cells. The amount of catalyst loading of this layer has a large effect on PEM fuel cell performance. Non-uniformity of reactant concentration could lead to a variation of current density in anode and cathode catalyst layer. The main reason for this phenomenon is porosity variation due to two effects: 1. compression of electrode on the solid landing area and 2. Water produced at the cathode side of diffusion layer. In this study the effect of variable current density in anode and cathode electrode on cell performance is...
Protein folding rates correlate with heterogeneity of folding mechanism
, Article Physical Review Letters ; Volume 93, Issue 20 , 2004 , Pages 208105-1-208105-4 ; 00319007 (ISSN) ; Ejtehadi, M. R ; Plotkin, S. S ; Sharif University of Technology
American Physical Society
2004
Abstract
The folding rates of protein were shown to correlate with the degree of heterogeneity in the formation of native contacts. It was shown that both experimental rates and simulated free energy barriers for 2-state proteins depend on the degree of heterogeneity present in the folding process. Heterogeneity due to variance in the distribution of native loop lengths, and variance in the distribution of φ values, were observed to increase folding rates and reduce folding barriers. The observed effect due to φ variance was found to be the most statistically significant, because φ variance captures both heterogeneity arising from native topology and that arising from energetics
Ferrofluidic open loop pulsating heat pipes: Efficient candidates for thermal management of electronics
, Article Experimental Heat Transfer ; Vol. 27, issue. 3 , Dec , 2014 , p. 296-312 ; ISSN: 08916152 ; Taslimifar, M ; Saidi, M. H ; Shafii, M. B ; Afshin, H ; Hannani, S. K ; Sharif University of Technology
Abstract
Thermal management of electronic devices is presently a serious concern. This article investigates the thermal performance of a five-turn open-loop pulsating heat pipe in both start-up and steady thermal conditions. The effects of working fluid, namely water and ferrofluid, heat input, charging ratio, ferrofluid concentration, orientation, as well as application of magnetic field, are explored. Experimental results show that using ferrofluid enhances the thermal performance in comparison with the case of distilled water under certain conditions. In addition, applying a magnetic field on the open-loop pulsating heat pipe charged with ferrofluid improves its thermal performance. Charging...
Nanofluidic transport inside carbon nanotubes
, Article Journal of Physics D: Applied Physics ; Volume 47, Issue 6 , 12 February , 2014 ; ISSN: 00223727 ; Moosavi, A ; Akbarzadeh, A. M ; Sharif University of Technology
Abstract
Using non-equilibrium molecular dynamics simulations, we investigate the effects of nanotube size, mean flow velocity, ion concentration and temperature of an electrolyte water solution on shearing stress and nominal viscosity. It is shown that the distributed electric field arising from the electrolyte water solution has significant influences on fluid properties. Also, the temperature of the solution, which causes thermal movement, affects nanofluidic transport in nanoenvironments. The nominal viscosity and shearing stress increases as the tube diameter increases. When the temperature of solution increases or ion concentration decreases, the shearing stress and nominal viscosity increase....