Loading...
Search for: performance
0.014 seconds
Total 2824 records

    Model Development for a Medium Turboshaft Engine

    , M.Sc. Thesis Sharif University of Technology Mazidi Sharaf Abadi, Vahid (Author) ; Mazaheri, Karim (Supervisor)
    Abstract
    In this thesis, our aim is to simulate steady and transient operation of a turboshaft engine with a free power turbine. For better understanding of physics of the problem, nested loops method is used in order to simulate the steady state operation. Furthermore, methods based on steady operation are used in simulating transient behavior of the engine. Scaling methods are used to extract performance characteristics of the engine components. It is assumed that performance characteristics have similar behavior in high engine shaft speeds. Bearing this in mind, validity of our simulations are confined to such high shaft speed conditions. In addition, for off design analyzes it is assumed that... 

    Task migration in mesh NOCs over virtual point-to-point connections

    , Article 19th International Euromicro Conference on Parallel, Distributed, and Network-Based Processing, PDP 2011, Ayia Napa, 9 February 2011 through 11 February 2011 ; 2011 , Pages 463-469 ; 9780769543284 (ISBN) Goodarzi, B ; Sarbazi Azad, H ; Sharif University of Technology
    Abstract
    Processor allocation in todays many core MPSoCs is a challenging task, especially since the order and requirements of incoming applications are unknown during design stage. To improve network performance, balance the workload across processing cores, or mitigate the effect of hot processing elements in thermal management methodologies, task migration is a method which has attracted much attention in recent years. Runtime task migration was first proposed in multicomputer with load balancing as the major objective. However, specific NoC properties such as limited amount of communication buffers, more sensitivity to implementation complexity, and tight latency and power consumption constraints... 

    Performance evaluation and enhancement of random access procedure in TETRA networks

    , Article 2010 6th Conference on Wireless Advanced, WiAD 2010, 27 June 2010 through 29 June 2010 ; June , 2010 ; 9781424470716 (ISBN) Azizzadeh, F ; Ghorashi, S. A ; Khodaian, A. M ; Sharif University of Technology
    2010
    Abstract
    In this paper, random access procedure in terrestrial trunked radio (TETRA) networks is described and modeled. Then, the impact of different random access parameters on performance metrics such as "delay" and "throughput" is evaluated. Moreover, in order to have a fast "call setup" which is one of the most important features of TETRA, it is shown that random access delay can be minimized, while maintaining peak throughput. by adaptively adjusting the random access parameters according to the backlogged traffic. The performance improvement of the proposed adaptive parameter adjustment is proved via extensive simulation results  

    Hybridization of rotary absorber tube and magnetic field inducer with nanofluid for performance enhancement of parabolic trough solar collector

    , Article Journal of Cleaner Production ; Volume 283 , 2021 ; 09596526 (ISSN) Bezaatpour, M ; Rostamzadeh, H ; Bezaatpour, J ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    A considerable amount of energy is lost in the parabolic trough solar collectors due to the poor capability of working fluid in full absorption of the concentrated solar irradiation across the receiver tube. A new hybrid method is recommended here to cover up such deficiency by simultaneously using a rotary absorber tube and magnetic field inducer with nanofluid. Results showed that the combination effects of the receiver rotation and the magnetic field improve the convection mechanism in the absorber and increase both energetic and exergetic performance of the collector. The study reveals that there is an optimal rotational speed in the each magnetic field intensity for different... 

    The impact of customer knowledge on the organizational performance: a system dynamics approach

    , Article Kybernetes ; 2021 ; 0368492X (ISSN) Bidgoli, S. D ; Owlia, M. S ; Isaai, M. T ; Sharif University of Technology
    Emerald Group Holdings Ltd  2021
    Abstract
    Purpose: The purpose of this research was to model the impact of customer knowledge on the performance of organization with a focus on information technology industry. Furthermore, it is intended to analyze the effect of customer knowledge investment on the performance measures, by reviewing investment policies. Design/methodology/approach: The relationship between customer knowledge and performance measures was specified using literature review and grounded theory method. The system dynamics approach was then applied to analyze the impact of the customer knowledge on the performance measures. Findings: This study provided a dynamic model on the causal relationship between customer knowledge... 

    Indoor wireless infrared channel characterization by measurements

    , Article IEEE Transactions on Vehicular Technology ; Volume 50, Issue 4 , 2001 , Pages 1053-1073 ; 00189545 (ISSN) Pakravan, M. R ; Kavehrad, M ; Hashemi, H ; Sharif University of Technology
    2001
    Abstract
    Use of infrared light for indoor wireless communications has received considerable attention recently. In this paper, we present results obtained from a large set of measurements performed at the University of Ottawa. We investigate impacts of receiver rotation and shadowing on the properties of indoor infrared channels. This paper contains a description of a measurement system developed and used throughout the experiments. Measurement results are used to find and present methods to estimate variations of channel path loss for small changes in the receiver direction, using statistical techniques. This would be useful for generating samples of channel path loss for system performance... 

    Finite element analysis of mechanical performance of nitinol biliary stent: effect of material properties [electronic resource]

    , Article Materials Research Innovations ; Vol 17, No. 2, 2013, 53-59 Nematzadeh, F. (Fardin) ; Sadrnezhaad, K ; Sharif University of Technology
    Abstract
    Stent implantation has been regarded as a major strategy to solve gastrointestinal diseases such as biliary obstruction during the last decade. The application of nitinol superelastic stents has been recently considered for minimising such problems as restenosis after stent implantation, the ability to low stent twist, unsuitable dynamic behaviour and inadequate strength radial of stent. In the present article, the effects of material properties on mechanical performance of Z shaped nitinol wire stent under crushing test for clinical applications are studied by finite element modelling. Nitinol stent shows better mechanical and clinical performance after applying 90% crushing, less chronic... 

    Effects of Crimping on Mechanical Performance of Nitinol Stent Designed for Femoral Artery: Finite Element Analysis [electronic resource]

    , Article Journal of Materials Engineering and Performance ; November 2013, Volume 22, Issue 11, pp 3228-3236 Nematzadeh, F. (Fardin) ; Sadrnezhaad, K ; Sharif University of Technology
    Abstract
    Nitinol stents are used to minimize improper dynamic behavior, low twistability, and inadequate radial mechanical strength of femoral artery stents. In this study, finite element method is used to investigate the effect of crimping and Austenite finish temperature (A f) of Nitinol on mechanical performance of Z-shaped open-cell femoral stent under crimping conditions. Results show that low A f Nitinol has better mechanical and clinical performance due to small chronic outward force, large radial resistive force, and appropriate superelastic behavior  

    Polypropylene-based microextraction method for determination of fluoxetine in human urine samples

    , Article Analytical Letters ; Volume 45, Issue 13 , 2012 , Pages 1777-1785 ; 00032719 (ISSN) Bagheri, H ; Marzancola, M. G ; Es'haghi, A ; Sharif University of Technology
    2012
    Abstract
    A polypropylene (PP) sheet was successfully applied as an extracting medium for trace enrichment of fluoxetine (FLX) from urine samples, followed by high performance liquid chromatography-fluorescence detection (HPLC-FD). The extraction medium was a square, 1 × 1 cm2 piece of polypropylene membrane sheet that was conditioned in methanol. The extraction process was conveniently carried out using a 5 mL urine sample. After extraction, the PP sheet was withdrawn and transferred to a glass vial for performing the desorption process using 210 μL organic solvent. After complete drying, the residue was dissolved in 50 μL of methanol and an aliquot of 20 μL was, finally, injected into the HPLC... 

    Transmit code design for extended target detection in the presence of clutter

    , Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, 19 April 2014 through 24 April 2014 ; Volume 2015-August , April , 2015 , Pages 3921-3925 ; 15206149 (ISSN) ; 9781467369978 (ISBN) Karbasi, S. M ; Naghsh, M. M ; Bastani, M. H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Abstract
    In this paper, we consider the problem of transmit code design to optimize the detection probability of an extended target embedded in Gaussian signal-dependent interference. We model the target with a priori known target impulse response (TIR) structure along with an unknown reflection factor. As is known, the performance of the generalized likelihood ratio test (GLRT) detector, for the case at hand, monotonically increases with the signal-to-interference-plus-noise ratio (SINR). Hence, we deal with the code design problem via maximizing the SINR. We also enforce a peak-to-average power ratio (PAR) constraint on the sought code. We devise a cyclic method to tackle the highly non-convex... 

    The extent of EFQM effectiveness in routine and non-routine organizations based on multivariate techniques: an empirical study

    , Article Operational Research ; 2016 , Pages 1-31 ; 11092858 (ISSN) Bagheri, F ; Noorossana, R ; Najmi, M ; Sharif University of Technology
    Springer Verlag  2016
    Abstract
    Despite the fact that a variety of analyses are conducted based on the performance of business excellence models according to organization type such as ownership, size and etc., the performance of organizations based on the factor of being routine or non-routine has not been investigated yet. In this paper, implementation of the European Foundation for Quality Management (EFQM) model for these types of organizations (routine and non-routine) has been examined. In order to do that, first we have developed a methodology to classify organizations into routine and non-routine categories. Then we have used discriminant analysis based on three factors, including process uncertainty, knowledge... 

    Relationship among culture of excellence, organisational performance and knowledge sharing: Proposed conceptual framework

    , Article International Journal of Productivity and Quality Management ; Volume 19, Issue 4 , 2016 , Pages 446-465 ; 17466474 (ISSN) Rezaei, G ; Gholami, H ; Shaharou, A. B. M ; Zameri Mat Saman , M ; Zakuan, N ; Najmi, M ; Sharif University of Technology
    Inderscience Enterprises Ltd  2016
    Abstract
    In today's competitive market, culture of excellence (CoE) and knowledge sharing (KS) are vital factors for organisations to thrive in the ever-expanding global market-economy. However, most previous studies have paid less attention to CoE especially in developing countries. In addition, they gave less attention to KS as a mediator in the CoE performance model. The purpose of this paper is to investigate the relationship among CoE, KS, and organisational performance (OP) in the sector of industrial companies in Iran, and to develop a conceptual framework based on extensive review of the literature. Based on a review of the literature, a link was established between CoE and OP. Furthermore,... 

    An opto-electrical NoC with traffic flow prediction in chip multiprocessors

    , Article Proceedings - 2014 22nd Euromicro International Conference on Parallel, Distributed, and Network-Based Processing, PDP 2014 ; 2014 , Pages 440-443 Ghane, M ; Arjomand, M ; Sarbazi Azad, H ; Sharif University of Technology
    Abstract
    Network-on-Chip (NoC) paradigm has emerged as a revolutionary methodology to integrate numerous IP blocks on a single chip. The achievable performance of adopting NoCs is constrained by the performance limitation mainly imposed by the metal wires that are the physical realization of communication channels. According to the International Technology Roadmap for Semiconductors (ITRS) report, new interconnect paradigms providing huge bandwidth is in need for future products. The current wired channels have limited bandwidth, and consequently, they limit the performance enhancements that NoC architectures can provide. Optical interconnects are capable of achieving better performance via... 

    Relationship between culture of excellence and organisational performance in Iranian manufacturing companies

    , Article Total Quality Management and Business Excellence ; 2016 , Pages 1-22 ; 14783363 (ISSN) Rezaei, G ; Mardani, A ; Amat Senin, A ; Yew Wong, K ; Sadeghi, L ; Najmi, M ; Shaharoun, A. M ; Sharif University of Technology
    Routledge 
    Abstract
    High-performing organisations are those which practise exemplary Culture of Excellence (CoE). Global competition dictates that only high-performing organisations will survive in the long term. This study attempts to focus on the relationship between CoE constructs and organisational performance (OP) in the context of Iranian manufacturing sector. Data are gathered via survey, of 222 excellence award-winning companies in Iran. The SPSS and smartPLS were used to test the relationship between CoE factors and OP. The result of correlation analysis proved that all 10 CoE constructs were significantly correlated with OP and there exists a significant relationship between CoE and OP. Strong... 

    Numerical investigation of geometric parameter effects on the aerodynamic performance of a Bladeless fan

    , Article Alexandria Engineering Journal ; Volume 55, Issue 1 , 2016 , Pages 223-233 ; 11100168 (ISSN) Jafari, M ; Afshin, H ; Farhanieh, B ; Sojoudi, A ; Sharif University of Technology
    Elsevier  2016
    Abstract
    Aerodynamic performance of a Bladeless fan is numerically investigated considering the effect of five geometric parameters. Airflow through this fan was analyzed by simulating a Bladeless fan within a 2 m × 2 m × 4 m room. Analysis of the flow field inside the fan and the evaluation of its performance were obtained by solving conservations of mass and momentum equations for the aerodynamic investigations. In order to design the Bladeless fan an Eppler 473 airfoil profile was used as the cross section of the fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter, and... 

    Finite element analysis of mechanical performance of nitinol biliary stent: effect of material properties

    , Article Materials Research Innovations ; Volume 17, Issue SUPPL 2 , December , 2013 , Pages S53-S59 ; 14328917 (ISSN) Nematzadeh, F ; Sadrnezhaad, S. K ; Sharif University of Technology
    Abstract
    Stent implantation has been regarded as a major strategy to solve gastrointestinal diseases such as biliary obstruction during the last decade. The application of nitinol superelastic stents has been recently considered for minimising such problems as restenosis after stent implantation, the ability to low stent twist, unsuitable dynamic behaviour and inadequate strength radial of stent. In the present article, the effects of material properties on mechanical performance of Z shaped nitinol wire stent under crushing test for clinical applications are studied by finite element modelling. Nitinol stent shows better mechanical and clinical performance after applying 90% crushing, less chronic... 

    A new approach to reduce memory consumption in lattice boltzmann method on GPU

    , Article Journal of Applied Fluid Mechanics ; Volume 10, Issue 1 , 2017 , Pages 55-67 ; 17353572 (ISSN) Sheida, M ; Taeibi Rahni, M ; Esfahanian, V ; Sharif University of Technology
    Isfahan University of Technology  2017
    Abstract
    Several efforts have been performed to improve LBM defects related to its computational performance. In this work, a new algorithm has been introduced to reduce memory consumption. In the past, most LBM developers have not paid enough attention to retain LBM simplicity in their modified version, while it has been one of the main concerns in developing of the present algorithm. Note, there is also a deficiency in our new algorithm. Besides the memory reduction, because of high memory call back from the main memory, some computational efficiency reduction occurs. To overcome this difficulty, an optimization approach has been introduced, which has recovered this efficiency to the original... 

    Achieving high mechanical performance in protrusion friction stir spot welding (PFSSW) of DQSK steel compared to other techniques

    , Article Materials Research Express ; Volume 5, Issue 10 , 2018 ; 20531591 (ISSN) Shahrabadi, A. R ; Mousavizade, S. M ; Ezatpour, H. R ; Pouranvari, M ; Sharif University of Technology
    Institute of Physics Publishing  2018
    Abstract
    Protrusion friction spot stir welding (PFSSW) was introduced as a novel method to produce keyhole-free welds of a drawing quality special killed low carbon steel (DQSK). The effects of welding parameters such as tool rotation speed and plunging depth were investigated on the mechanical properties and metallurgical aspects. The sheet/sheet joint interface of the welds produced by PFSSW was visible and non-planar compared to the conventional FSSW method. Microstructure and hardness were affected by dynamic recrystallization and transformation hardening in the stir zone. Hardness value of the stir zone produced by the present work was much lower than that produced by resistance spot welding... 

    Relationship between culture of excellence and organisational performance in Iranian manufacturing companies

    , Article Total Quality Management and Business Excellence ; Volume 29, Issue 1-2 , 2018 , Pages 94-115 ; 14783363 (ISSN) Rezaei, G ; Mardani, A ; Senin, A. A ; Wong, K. Y ; Sadeghi, L ; Najmi, M ; Shaharoun, A. M ; Sharif University of Technology
    Routledge  2018
    Abstract
    High-performing organisations are those which practise exemplary Culture of Excellence (CoE). Global competition dictates that only high-performing organisations will survive in the long term. This study attempts to focus on the relationship between CoE constructs and organisational performance (OP) in the context of Iranian manufacturing sector. Data are gathered via survey, of 222 excellence award-winning companies in Iran. The SPSS and smartPLS were used to test the relationship between CoE factors and OP. The result of correlation analysis proved that all 10 CoE constructs were significantly correlated with OP and there exists a significant relationship between CoE and OP. Strong... 

    Practical techniques for improving the performance of polymeric membranes and processes for protein separation and purification

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 37, Issue 2 , February , 2018 , Pages 1-23 ; 10219986 (ISSN) Vedadghavami, A ; Minooei, F ; Hosseini, S. S ; Sharif University of Technology
    Iranian Journal of Chemistry and Chemical Engineering  2018
    Abstract
    Protein separation and purification technologies play an essential role in various industries including but not limited to pharmaceuticals, dairy as well as the food sector. Accordingly, a wide variety of techniques such as chromatography and electrophoresis have been developed and utilized extensively over the years for this purpose. Despite their widespread acceptance, conventional techniques still suffer from major limitations and complexities such as short lifetime, low productivity, high-pressure drop and difficulty in scale-up among others. Membrane separation processes have received significant attention in recent years as a promising alternative that can potentially overcome the...