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Main System Investigation of Turbocharged Diesel Engine During Performance Upgrade
, M.Sc. Thesis Sharif University of Technology ; Hajilouy Benisi, Ali (Supervisor) ; Nouri Broujerdi, Ali (Supervisor)
Abstract
The internal combustion engine power is determined by the amount of fuel effectively burned inside the engine cylinders. On the other hand, the fuel consumption is proportional to the air mass that enters the cylinders in each cycle. Conventionally, incoming the engine inlet air is at ambient conditions. However, with higher air density, the engine power increases for the same dimensions, so-called turbocharging. Although the engine's structure remains unchanged, it may be necessary to adjust the main systems of the engine simultaneously. This research investigated maximizing the power of a turbocharged diesel engine based on upgrading the degree of turbocharging. For this purpose, the EM355...
Design and analysis of optimum distribution free OS-CFAR for non coherent radars
, Article International Radar Symposium, IRS 2005, 6 September 2005 through 8 September 2005 ; Volume 2005-January , 2005 ; 21555753 (ISSN) ; Sheikhi, A ; Nayebi, M. M ; DLR; EADS; serco - bringing service to life; sms GmbH; Technische Universitat Hamburg-Harburg (TUHH) ; Sharif University of Technology
IEEE Computer Society
2005
Abstract
In this paper, general form of optimum distribution free (D.F.) detector for noncoherent radars is extracted. This general form is very complex to be analyzed, therefore, we have derived two special cases and one case which is more interesting and practical is analyzed accurately. We have shown that in spite of its simple form, the detector has considerable benefits over conventional OSCFAR schemes
Minimum control effort trajectory planning and tracking of the CEDRA brachiation robot [electronic resource]
, Article Robotica ; Robotica / Volume 31 / Issue 07 / October 2013, pp 1119-1129 ; Lavasan, S. M. H ; Norouz, M ; Rahimi Mousavi, M. S ; Sharif University of Technology
Abstract
The control of a brachiation robot has been the primary objective of this study. A brachiating robot is a type of a mobile arm that is capable of moving from branch to branch similar to a long-armed ape. In this paper, to minimize the actuator work, Pontryagin's minimum principle was used to obtain the optimal trajectories for two different problems. The first problem considers “brachiation between fixed branches with different distance and height,” whereas the second problem deals with the “brachiating and catching of a moving target branch”. Theoretical results show that the control effort in the proposed method is reduced by 25% in comparison with the “target dynamics” method which was...
Hybrid stochastic/robust flexible and reliable scheduling of secure networked microgrids with electric springs and electric vehicles
, Article Applied Energy ; Volume 300 , 2021 ; 03062619 (ISSN) ; Aghaei, J ; Pirouzi, S ; Niknam, T ; Fotuhi Firuzabad, M ; Shafie khah, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Electric spring (ES) as a novel concept in power electronics has been developed for the purpose of dealing with demand-side management. In this paper, to conquer the challenges imposed by intermittent nature of renewable energy sources (RESs) and other uncertainties for constructing a secure modern microgrid (MG), the hybrid distributed operation of ESs and electric vehicles (EVs) parking lot is suggested. The proposed approach is implemented in the context of a hybrid stochastic/robust optimization (HSRO) problem, where the stochastic programming based on unscented transformation (UT) method models the uncertainties associated with load, energy price, RESs, and availability of MG equipment....
Study on the Mass Transfer and Isotope Separation Phenomena in a Gas Centrifuge by Using FEREON Mixtures as Model Compounds
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Karimi-Sabet, Javad (Supervisor) ; Norouzi, Ali (Co-Advisor)
Abstract
In the nuclear industry, gas centrifuges are considered of high importance for the purpose of uranium enrichment. Today, with advances in science and technology, the use of gas centrifuges for separating isotopes other than uranium, is so common. With respect to the use of conventional methods such as Pancake equation in calculating the velocity profile in centrifuges, it is needed that A^2=(MV^2)/2RT≫1 (M: Feed molecular weight; V: Peripheral speed of centrifuge; T: Mean temperature of feed; R: The universal constant of gases). While the molecular weight of the feed mixture gets lower, the A2 parameter gets closer to one. So, other methods for modeling the behavior of the gas in the...
Target detection by passive coherent FM based bistatic radar
, Article 2008 International Conference on Radar, Radar 2008, Adelaide, SA, 2 September 2008 through 5 September 2008 ; October , 2008 , Pages 412-415 ; 9781424423224 (ISBN) ; Nayebi, M. M ; Norouzi, Y ; CEA Technologies Pty Ltd; Cranfield University; Diversified Technologies, Inc; Information, Telecommunications and Electronic Engineering (ITEE); Board of Engineers Australia ; Sharif University of Technology
2008
Abstract
Bistatic passive radars have many advantages over the monostatic ones because they are undetectable and silent. In passive coherent location, the original source of energy is derived from a waveform of opportunity in the environment and the re-radiated energy from the target is processed to decide about the existence of the target. More over bistatic radars receive forward scatters from target in place of the backscatters in monostatics systems. As a result of the larger forward scattered RCS, the stealth targets can be detected easier. Passive radar does not need any frequency allocation so are very attractive for surveillance. Multipath effects and direct path interference are two problems...
Intelligent semi-active vibration control of eleven degrees of freedom suspension system using magnetorheological dampers
, Article Journal of Mechanical Science and Technology ; Volume 26, Issue 2 , 2012 , Pages 323-334 ; 1738494X (ISSN) ; Sarrafan, A ; Khayyat, A. A. A ; Zabihollah, A ; Sharif University of Technology
2012
Abstract
A novel intelligent semi-active control system for an eleven degrees of freedom passenger car's suspension system using magnetorheological (MR) damper with neuro-fuzzy (NF) control strategy to enhance desired suspension performance is proposed. In comparison with earlier studies, an improvement in problem modeling is made. The proposed method consists of two parts: a fuzzy control strategy to establish an efficient controller to improve ride comfort and road handling (RCH) and an inverse mapping model to estimate the force needed for a semi-active damper. The fuzzy logic rules are extracted based on Sugeno inference engine. The inverse mapping model is based on an artificial neural network...
Performance and exhaust emission characteristics of a spark ignition engine operated with gasoline and CNG blend
, Article Proceedings of the Spring Technical Conference of the ASME Internal Combustion Engine Division ; 2012 , Pages 179-187 ; 15296598 (ISSN) ; 9780791844663 (ISBN) ; Hamidi, A. A ; Mozafari, A. A ; Sharif University of Technology
2012
Abstract
Using CNG as an additive for gasoline is a proper choice due to higher octane number of CNG enriched gasoline with respect to that of gasoline. As a result, it is possible to use gasoline with lower octane number in the engine. This would also mean the increase of compression ratio in SI engines resulting in higher performance and lower gasoline consumption. Over the years, the use of simulation codes to model the thermodynamic cycle of an internal combustion engine have developed tools for more efficient engine designs and fuel combustion. In this study, a thermodynamic cycle simulation of a conventional four-stroke spark-ignition engine has been developed. The model is used to study the...
A comparative study of the performance of a SI engine fuelled by natural gas as alternative fuel by thermodynamic simulation
, Article 2009 ASME Internal Combustion Engine Division Fall Technical Conference, ICEF 2009, Lucerne, 27 September 2009 through 30 September 2009 ; 2009 , Pages 49-57 ; 9780791843635 (ISBN) ; Hamidi, A. A ; Mozafari, A. A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2009
Abstract
With the declining energy resources and increase of pollutant emissions, a great deal of efforts has been focused on the development of alternatives for fossil fuels. One of the promising alternative fuels to gasoline in the internal combustion engine is natural gas [1-5]. The application of natural gas in current internal combustion engines is realistic due to its many benefits. The higher thermal efficiency due to the higher octane value and lower exhaust emissions including CO2 as a result of the lower carbon to hydrogen ratio of the fuel are the two important feature of using CNG as an alternative fuel. It is well known that computer simulation codes are valuable economically as a cost...
Analytical and experimental analyses of nonlinear vibrations in a rotary inverted pendulum
, Article Nonlinear Dynamics ; Volume 107, Issue 3 , 2022 , Pages 1887-1902 ; 0924090X (ISSN) ; Pasharavesh, A ; Khayyat, A. A. A ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Gaining insight into possible vibratory responses of dynamical systems around their stable equilibria is an essential step, which must be taken before their design and application. The results of such a study can significantly help prevent instability in closed-loop stabilized systems by avoiding the excitation of the system in the neighborhood of its resonance. This paper investigates nonlinear oscillations of a rotary inverted pendulum (RIP) with a full-state feedback controller. Lagrange’s equations are employed to derive an accurate 2-DoF mathematical model, whose parameter values are extracted by both the measurement and 3D modeling of the real system components. Although the governing...
A suction-controlled ring device to measure the coefficient of lateral soil pressure in unsaturated soils
, Article Geotechnical Testing Journal ; Volume 44, Issue 1 , 2020 ; Garakani, A. A ; Golshani, A ; Mirzaii, A ; Sharif University of Technology
ASTM International
2020
Abstract
A suction-controlled ring device has been developed to continuously measure the coefficient of lateral soil pressure in deformable unsaturated soil samples from the at-rest to the active condition under application of increasing vertical pressure and controlled matric suction. The device incorporates a thin aluminum specimen ring equipped with horizontal strain gages for recording the lateral soil strains. In addition, a sensor recording water volume changes is utilized to continuously monitor the degree of saturation of the soil sample during tests. The matric suction within the soil texture is controlled using the axis translation technique. In order to verify the performance of the ring...
Gum tragacanth gels as a new supporting matrix for immobilization of whole-cell
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 24, Issue 4 , 2005 , Pages 1-7 ; 10219986 (ISSN) ; Vaziri, A ; Seifkordi, A. A ; Kheirolomoom, A ; Sharif University of Technology
2005
Abstract
We introduce a new smooth, non-toxic, biocompatible method for cross-linking of gum tragacanth (GT), a polysaccharide of natural origin, in order to serve as a new supporting matrix for immobilization systems. The modified gum is used as a matrix for the catalysis of the conversion of benzyl penicillin to 6-aminopenicillanic acid (6-APA) by means of Escherichia coli ATCC11105 with penicillin G acylase (PGA) activity. The results show that GT beads can not only serve as a proper matrix for immobilization, but show enhanced hydrolysis rate and stability compared to other immobilization systems used for this reaction. This signifies the potential of GT as a biocompatible matrix for...
True Class-E Design For Inductive Coupling Wireless Power Transfer Applications
, Article 30th International Conference on Electrical Engineering, ICEE 2022, 17 May 2022 through 19 May 2022 ; 2022 , Pages 864-868 ; 9781665480871 (ISBN) ; Safarian, A ; Fotowat Ahmady, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
The Class-E power amplifier has been widely studied and formulated in the literature. Although the majority of reported inductive coupling wireless power transfer (WPT) systems use a class-E power amplifier for driving the primary coil, still there is a lack of a comprehensive study on class-E circuit dedicated to WPT, providing a set of closed form design equations for proper class-E operation. This paper presents the required design equations needed to design a 'true' class-E circuit for WPT applications. Equations for the series-tuned secondary coil WPT system are presented, as well as two different design procedures for the parallel-tuned secondary coil. The derived equations have been...
Crashworthiness determination of side doors and B pillar of a vehicle subjected to pole side impact
, Article Applied Mechanics and Materials ; Vol. 663, issue , 2014 , p. 552-556 ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2014
Abstract
Pole Side Impact Tes is one out of three crash tests described by Euro NCAP standard for star rating of a vehicle and is required for assessing the Adult Occupant Protection. In this paper the goal is to determine the crashworthiness of side doors and B pillar in a Pole Side Impact Test based on Euro New Car Assessment Program (Euro-NCAP) using computer and simulation method. In this matter, a vehicle model has been prepared and meshed using Hypermesh and CATIA. The velocity of 29 km/h has been assigned to the vehicle which was on top of a cart while the pole has been assigned as a rigid static object based on Euro NCAP requirements specifically. Results show that different amounts of energy...
Investigation of Thickness Influences On Energy Absorption For Side Doors And B Pillar In Euro NCAP Pole Side Impact Test
, Article Applied Mechanics and Materials ; Vol. 663, issue , Oct , 2014 , p. 585-589 ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2014
Abstract
To assess a car under the Euro New Car Assessment Program (Euro-NCAP), Adult Occupant Protection is one out of three parameters which need to be calculated with a weight factor of 50% while the other parameters, Child Occupant Protection and Pedestrian Occupant Protection, have a weight factor of 20%. The Pole Side Impact Test, beside two other tests, Side and Front Impact, is also required to calculate the Adult Occupant Protection. It shows how important the Pole Side Impact Test is and what an effective role it has in the car rating assessment. In this paper, the objective is to evaluate the effect of thickness on the energy absorbed by the side doors and the B pillar and its...
Crashworthiness determination for front and rear doors and B pillar subjected to side impact crash by a mobile deformable barrier
, Article Advanced Science Letters ; Volume 19, Issue 2 , 2013 , Pages 392-395 ; 19366612 (ISSN) ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2013
Abstract
In Euro NCAP standard, adult protection is one of the most important rating scores with 50% weight factor while child protection and pedestrian protection are accounted into consideration with 20% weight factor. For adult protection testing, three tests are required to perform: (1) side impact, (2) pole impact, (3) front impact. In the side impact test, dummy's head, chest, shoulder, thorax, ribs, abdomen, pelvic and femur must be studied to evaluate the rating score. Crashworthiness of a car during side impact can describe the score rated for that car. In this paper the goal is to determine the crashworthiness of side doors and B-pillar in side impact crash est by simulation using LS DYNA...
Effect of material and thickness of side doors and B pillar on crashworthiness in euro NCAP side impact crash test
, Article Advanced Science Letters ; Volume 19, Issue 2 , 2013 , Pages 420-424 ; 19366612 (ISSN) ; Faieza, A. A ; Sahari, B. B ; Nuraini, A. A ; Halali, M ; Sharif University of Technology
2013
Abstract
In side impact test which is one out of three tests of Euro NCAP standard, front and rear doors and B pillar are most absorbance parts among vehicle body parts. Passengers are highly in danger while side crash, because of the distance between passenger's head and vehicle body. In this paper effect of material and thickness of doors and B-pillar and their absorbed energy during crash and improvement of its crashworthiness with respect to light weight design are studied using LS DYNA solver. The objective of this paper is to propose a material for doors and B-pillar with a specified thickness to achieve maximum absorbed energy and minimum weight. The shape of the doors and B-pillar remains...
Effect of recycle gas composition of the performance of Fischer-Tropsch catalyst
, Article Petroleum Science and Technology ; Volume 28, Issue 5 , 2010 , Pages 458-468 ; 10916466 (ISSN) ; Khorashe, F ; Safekordi, A. A ; Tavassoli, A ; Sharif University of Technology
2010
Abstract
In this study, the influence of CO2 and CH4 on the performance and selectivity of Co-Ru/Al2O3 catalyst is investigated by injection of these gases (0-20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO2 in the feed stream do not change the catalyst activity, but increasing the amount of CO2 (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature,...
Simulation and estimation of normal dispersion phenomenon in an acentric organic crystal (NPP) by the quantum photonic approach
, Article Modelling and Simulation in Materials Science and Engineering ; Volume 15, Issue 8 , 2007 , Pages 869-878 ; 09650393 (ISSN) ; Zarch, A. W ; Oskouei, A. A ; Amjadi, A ; Sharif University of Technology
2007
Abstract
In this paper, we present a nano-quantum photonic approach for the calculation of normal dispersion phenomena in organic crystals such as N-(4-nitrophenyl)-L-prolinol(NPP). We assume that a laser beam consists of a flow of energetic particles that interact with the distorted π-electron system. We approximate the distorted π-electron cloud by an ellipse to simplify calculations. By the precise analysis of photon interaction with the π-electron system of benzene ring in the NPP crystal, we obtain the refractive index in any wavelength by Monte Carlo simulation. The maximum error between our simulation results and the measurement data is 0.058, which is agreeable. © 2007 IOP Publishing Ltd
Water electrolyte transport through corrugated carbon nanopores [electronic resource]
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 90, Issue 1, July 2014, Article number 012304 ; Moosavi. A
Abstract
We investigate the effect of wall roughness on water electrolyte transport characteristics at different temperatures through carbon nanotubes by using nonequilibrium molecular dynamics simulations. Our results reveal that shearing stress and the nominal viscosity increase with ion concentration in corrugated carbon nanotubes (CNTs), in contrast to cases in smooth CNTs. Also, the temperature increase leads to the reduction of shearing stress and the nominal viscosity at moderate degrees of wall roughness. At high degrees of wall roughness, the temperature increase will enhance radial movements and increases resistance against fluid motion. As the fluid velocity increases, the particles do not...