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    Investigation of concrete beam behavior in FRP composite layering under incremental loading

    , Article International Journal of Applied Engineering Research ; Volume 11, Issue 4 , 2016 , Pages 2429-2435 ; 09734562 (ISSN) Zarringol, M ; Zarringol, M ; Sharif University of Technology
    Research India Publications  2016
    Abstract
    In this paper, we investigate concrete beam behavior in FRP composite layering under incremental loading. In doing so, we examined four beams with cross section of 200 mm, height of 150 mm and length of 2300 mm. Of these four beams, three were strengthened by FRP sheets with various layer numbers and one was set as the benchmark. The laboratorial samples of the second series were beams with cross section of 150 mm, height of 200 mm and length of 2000 mm. We strengthened the samples by CFRP sheets with various widths and layer numbers and set the other two as benchmark. We examined the standard cylindrical samples and the strengthened and control beams under incremental loading. For this... 

    Impact of difference of feeder impedances on the performance of a static transfer switch

    , Article IEEE Transactions on Power Delivery ; Volume 19, Issue 2 , 2004 , Pages 679-685 ; 08858977 (ISSN) Mokhtari, H ; Iravani, M. R ; Sharif University of Technology
    2004
    Abstract
    Conventionally, control system of a static transfer switch (STS) is designed based on the assumption that the STS terminal voltages are in-plane. This paper investigates the impact of phase difference of the STS terminal voltages on the STS transfer time and cross current. The phase difference is assumed to be a result of the difference of the feeder impedances. The paper shows that phase differences of even up to 4.5°, which are accompanied by up to 5% voltage drop at the STS terminal, can noticeably increase the transfer time and the cross current magnitude. The studies are conducted on the IEEE STS-1 benchmark system using the PSCAD/EMTDC software  

    Application of β-unzipping method in offshore system reliability analysis under changing load pattern

    , Article 22nd International Conference on Offshore Mechanics and Arctic Engineering; Safety and Reliability Pipeline Technology, Cancun, 3 June 2001 through 13 June 2001 ; Volume 2 , 2003 , Pages 77-83 Daghigh, M ; Makouie, S. H ; Sharif University of Technology
    2003
    Abstract
    This paper is concerned with the reliability assessment of a fixed platform operating in intermediate water depth under extreme environmental conditions. The structure is modelled by two-dimensional frame structure and subjected to quasi-static loads. Extreme wave loads acting on the platform in the unidirectioal mode are estimated together with their probabilistic characteristics. Fully plastic capacities of the members are also treated as random variables. The structure is modelled as a plane truss by using beam-column models and the plastic collapse of the structure is evaluated by using a linearized plasticity condition of the section under effect of axial force to generate the safety... 

    Transient behavior of load transformer during subcycle bus transfer

    , Article IEEE Transactions on Power Delivery ; Volume 18, Issue 4 , 2003 , Pages 1342-1349 ; 08858977 (ISSN) Mokhtari, H ; Iravani, M. R ; Dewan, S. B ; Sharif University of Technology
    2003
    Abstract
    Fast (subcycle) bus transfer by means of a static transfer switch (STS) requires short time intervals for detection and transfer process. Due to these time intervals, the load transformer is subjected to a transient process which can be accompanied by large transient current components through the transformer. The transient current, in turn, can cause voltage sag at the load terminal. The STS control logic must be able to distinguish such a voltage sag from those due to the supply disturbances and not disconnect the load. This paper provides simplified analytical expressions to predict F of the load transformer which can be used to estimate the corresponding voltage sag. PSCAD/EMTDC-based... 

    Fracture behaviour of isotactic polypropylene under static loading condition

    , Article Materials and Design ; Volume 24, Issue 2 , 2003 , Pages 105-109 ; 02641275 (ISSN) Zebarjad, S. M ; Bagheri, R ; Lazzeri, A ; Serajzadeh, S ; Sharif University of Technology
    Elsevier Ltd  2003
    Abstract
    The fracture mechanism of isotactic polypropylene has been studied by three- and four-point bending tests. The result of three-point bending test shows that a wide spread damage zone is present in front of the notch. Looking in more detail via cross-polarised light shows the evidence of birefringence in the stress-whitened zone. Increasing the applied load causes it to spread out the stress-whitened zone. Then the craze-like features are nucleated inside the stress-whitened region. The result of four-point bending test shows that craze-like damage appears in front of pre-crack and its propagation is dictated by spherulite microstructure. © 2003 Elsevier Science Ltd. All rights reserved  

    Impacts of load pattern variation in Iran power system on generation system planing

    , Article Canadian Conference on Electrical and Computer Engineering 2005, Saskatoon, SK, 1 May 2005 through 4 May 2005 ; Volume 2005 , 2005 , Pages 2216-2219 ; 08407789 (ISSN) Salimi Beni, A ; Gharagozloo, H ; Fotuhi Firuzabad, M ; Farrokhzad, D ; Sharif University of Technology
    2005
    Abstract
    During last decade, the electricity demand in Iran grows up more than 8% per year due to an increasing economic growth. The main part of this load growth is related to industrial and agricultural demand. At this period, electric utilities tried to provide the peak load demand using all different types of available generating units especially with hydro generation plants. However, moving the time of peak demand occurring from night hours to day time and also increasing of load demand at mid day hours, created a new challenge to hydro-generation planning. As the number of daily peak hours increases from the nightly to daily peak hours and considering that Iran is a sub-tropical country, use of... 

    A method to calculate the linear load pay back factors for air conditioners

    , Article Asia-Pacific Power and Energy Engineering Conference, APPEEC ; 2012 ; 21574839 (ISSN) ; 9781457705472 (ISBN) Ziaii, M ; Kazemi, A ; Fotuhi Firuzabad, M ; Parvania, M ; Sharif University of Technology
    Abstract
    Load pay back effect is the excess of load as a result of load curtailment, observed in direct load control programs related to thermostatically controlled appliances. In this paper, according to a stochastic difference equation, the load profile of an aggregation of customers without control will be attained. Then the assumption to consider load pay back as linear will be examined through simulations. Afterwards, based on a data structure gained from performing load curtailments at each interval, least-square method will be used to fit load pay back factors for each interval. It is notable that there are some significant differences between the results attained in this paper and what was... 

    Intelligent topology-oriented load shedding scheme in power systems

    , Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 652-656 ; 9781728115085 (ISBN) Zare, F ; Ranjbar, A ; Faghihi, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Load shedding is a prevalent emergency control designed to prevent system blackouts. The higher complexity and lower predictability of modern power systems makes it difficult to rely on conventional load shedding schemes which shed loads in pre-defined steps without sufficient consideration of the actual system characteristics and the disturbance situations. In case of large disturbances, the power system stability can be improved by optimal load shedding in more effective load buses. Proposed scheme utilizes improved Power Flow Tracing method to determine the amount and location of load drops considering power system constraints. Numerical simulations conducted on IEEE 39 bus standard test... 

    Axisymmetric thermo-electro-elastic analysis of a piezoelectric half space

    , Article Mathematics and Mechanics of Solids ; Volume 17, Issue 5 , September , 2012 , Pages 500-515 ; 10812865 (ISSN) Kargarnovin, M. H ; Hashemi, R ; Hashemi, M ; Sadeghi, H ; Sharif University of Technology
    2012
    Abstract
    In this study, an analytical solution is presented for thermo-electro- elastic analysis of piezoelectric semi-infinite bodies. For this purpose, governing equations are derived for a transversely isotropic piezoelectric material under an axisymmetric thermo-electro-mechanical loading condition. A general closed-form analytical solution is presented for the complementary and particular parts of the components of the displacement vector and also for the electric potential function. Then, boundary conditions are imposed and in that case an explicit solution is obtained for piezoelectric semi-infinite bodies. Results show that when a piezoelectric half space is subjected to constant/ramp surface... 

    Game theoretic based charging strategy for plug-in hybrid electric vehicles

    , Article IEEE Transactions on Smart Grid ; Vol. 5,Issue. 5 , 2014 , pp. 2368-2375 ; ISSN: 19493053 Bahrami, S ; Parniani, M ; Sharif University of Technology
    Abstract
    In the future smart grids, Plug-in Hybrid Electric Vehicles (PHEVs) are seen as an important means of transportation to reduce greenhouse gas emissions. One of the main issues regarding to this sort of vehicles is managing their charging time to prevent high peak loads over time. Deploying advanced metering and automatic chargers can be a practical way not only for the vehicle owners to manage their energy consumption, but also for the utilities to manage the electricity load during the day by shifting the charging loads to the off-peak periods. Additionally, an efficient charging schedule can reduce the users' electricity bill cost. In this paper we propose a new practical demand response... 

    Optimization of synthetic conditions CMC-g-poly (acrylic acid)/celite composite superabsorbent by taguchi method and determination of its absorbency under load

    , Article Express Polymer Letters ; Volume 1, Issue 8 , 2007 , Pages 488-494 ; 1788618X (ISSN) Pourjavadi, A ; Amini Fazl, M. S ; Ayyari, M ; Sharif University of Technology
    2007
    Abstract
    A novel biopolymer-based composite hydrogel was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the carboxymethyl cellulose (CMC). The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with five factors and four levels. In the synthesis of the composite superabsorbent, N,N'-methylene bisacrylamide (MBA) as crosslinker, ammonium persulfate (APS) as initiator, acrylic acid (AA) as monomer, CMC/Celite weight ratio and neutralization percent (NU) were used as... 

    A heuristic and GRASP algorithm for three-dimensional multiple bin-size bin packing problem based on the needs of a spare-part company

    , Article International Journal of Services and Operations Management ; Volume 38, Issue 1 , 2021 , Pages 73-91 ; 17442370 (ISSN) Sangchooli, A. S ; Sajadifar, S. M ; Sharif University of Technology
    Inderscience Publishers  2021
    Abstract
    The three-dimensional multiple bin-size bin packing problem (3D-MBSBPP) has many practical applications in the logistic problems such as warehouse management, transportation planning and container loading. An efficient solution to the problem can have significant effects on reducing the transportation costs, improving the status and increasing the productivity and profitability of the companies. The mathematical models proposed for this problem are few in number and can, therefore, be expanded and improved much further. In this paper, based on the needs of a spare-part company in Iran, we developed a mathematical model for 3D-MBSBPP. This model takes into account the rotation of the boxes... 

    Dynamics of Timoshenko beams on Pasternak foundation under moving load

    , Article Mechanics Research Communications ; Volume 31, Issue 6 , 2004 , Pages 713-723 ; 00936413 (ISSN) Kargarnovin, M. H ; Younesian, D ; Sharif University of Technology
    2004
    Abstract
    The response of a Timoshenko beam with uniform cross-section and infinite length supported by a generalized Pasternak-type viscoelastic foundation subjected to an arbitrary-distributed harmonic moving load is studied in this paper. Governing equations are solved using complex Fourier transformation in conjunction with the residue and convolution integral theorems. The solution is directed to compute the deflection, bending moment and shear force distribution along the beam length. A parametric study is carried out for an elliptical load distribution and influences of the load speed and frequency on the beam responses are investigated. © 2004 Elsevier Ltd. All rights reserved  

    Signal and noise improvement of travelling wave fet mixers

    , Article 2nd International Conference on Microwave and Millimeter Wave Technology, ICMMT 2000, 14 September 2000 through 16 September 2000 ; 2000 , Pages 76-79 ; 0780357434 (ISBN); 9780780357433 (ISBN) Moradi, G ; Abdipour, A ; Farzaneh, F ; Ghorbani, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2000
    Abstract
    The influence of the loading of the FET electrodes, on signal and noise performances of the device in mixer application is studied. It is shown that exciting the input signal from one end of the gate and extracting the output signal from the opposite ends of the gate can improve the device characteristics, provided that the two remaining ends of the gate and the drain are properly loaded. This structure makes the lines (i.e. the gate and the drain electrodes) to be matched with the loads. Therefore it leads to a travelling wave FET mixer, which is a good candidate for high power mm-wave application. © 2000 IEEE  

    Molecular dynamics investigation of β-SiC behavior under three-axial tensile loading [electronic resource]

    , Article Journal of Computational and Theoretical Nanoscience ; November 2011, Volume 8, Number 11, PP. 2187-2192 Mortazavi, B ; Simchi, A. (Abdolreza) ; Besharati-Givi, M.K ; Rajabpour, A ; Sharif University of Technology
    Abstract
    Molecular dynamics (MD) simulations were used to study the mechanical behaviour of β-SiC at nano-scale under tensile loading. Effects of loading rate and tensile temperature on the mechanical properties and failure were studied. Modified embedded-atom method (MEAM) potential and Berendsen thermostat were utilized for modelling. Periodic boundary conditions were employed and the behaviour of material was analyzed under three-axial loading condition at which the stress–strain relation was acceptably size independent. It is shown that with increasing the loading rate from 5 m/s to 70 m/s, the failure strain increases without a remarkable change in the stress–strain relationship. The MD... 

    Effect of cyclic loading on the temporomandibular joint

    , Article Lecture Notes in Engineering and Computer Science ; Volume 1 , 2014 , Pages 655-658 ; ISSN: 20780958 ; ISBN: 9789881925275 Muhandiram, J ; Wang, B ; Chizari, M ; Sharif University of Technology
    Abstract
    This research is aiming to investigate the mechanical behaviour of the temporomandibular joint (TMJ), in response to kinematics/cyclical loading caused through actions of speech and mastication. A set of in-vitro experimental tests has been performed in three different groups on a fresh sheep jaw bone to examine the hypothesis of the study. No failure was monitored during the cyclical test. The study was concluded that the amount of loading is effective on the displacement of the TMJ  

    Can simple trunk muscle models balance and stabilize lumbar spine during support of symmetric and asymmetric loads? a FE model study

    , Article 2007 ASME Summer Bioengineering Conference, SBC 2007, Keystone, CO, 20 June 2007 through 24 June 2007 ; 2007 , Pages 443-444 ; 0791847985 (ISBN); 9780791847985 (ISBN) Kiapour, A ; Shirazi Adl, A ; Parnianpour, M ; Sharif University of Technology
    2007

    Modeling and analysis of the dynamic response of an off-grid synchronous generator driven micro hydro power system

    , Article International Journal of Renewable Energy Development ; Volume 10, Issue 2 , 2021 , Pages 373-384 ; 22524940 (ISSN) Ali, W ; Farooq, H ; Rasool, A ; Sajjad, I. A ; Zhenhua, C ; Ning, L ; Sharif University of Technology
    Diponegoro university Indonesia - Center of Biomass and Renewable Energy (CBIORE)  2021
    Abstract
    This paper models and analyses the dynamic response of a synchronous generator driven off-grid micro hydro power system using Simulink tool of MATLAB software. The results are assessed from various perspectives including regulation through no load to full load and overload scenarios under normal and abnormal operating conditions. The investigation under the normal conditions of no load, linearly changing load and full load divulges that the system operates in a satisfactory manner as generator voltage and frequency remain approximately constant at 1 pu. However, at full load generator voltage and frequency drop 3% and 0.5% respectively from its nominal values but remain within prescribed... 

    Investigating the behavior of circular concrete filled PVC tube columns under concentric and eccentric load using FEM

    , Article Asian Journal of Civil Engineering ; Volume 22, Issue 4 , 2021 , Pages 589-603 ; 15630854 (ISSN) Alinejad, A ; Khaloo, A ; Hassanpour, S ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    The purpose of this research is to investigate the response of concrete-filled composite tube column under concentric and eccentric loads. To evaluate the influence of PVC pipe on the behavior of concrete-filled composite tubes, concrete-filled PVC pipe (CFPT) were modeled by ABAQUS software. The results demonstrate that the presence of the PVC pipe makes the concrete column more ductile and have a significant effect on the stress–strain curve of the CFPT after the peak strength, in a way that the confinement increased by raising the thickness of PVC pipe, but the confinement effect of the PVC pipe decreased by the increment of the column diameter and compressive strength of the concrete... 

    Investigating the behavior of circular concrete filled PVC tube columns under concentric and eccentric load using FEM

    , Article Asian Journal of Civil Engineering ; Volume 22, Issue 4 , 2021 , Pages 589-603 ; 15630854 (ISSN) Alinejad, A ; Khaloo, A ; Hassanpour, S ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    The purpose of this research is to investigate the response of concrete-filled composite tube column under concentric and eccentric loads. To evaluate the influence of PVC pipe on the behavior of concrete-filled composite tubes, concrete-filled PVC pipe (CFPT) were modeled by ABAQUS software. The results demonstrate that the presence of the PVC pipe makes the concrete column more ductile and have a significant effect on the stress–strain curve of the CFPT after the peak strength, in a way that the confinement increased by raising the thickness of PVC pipe, but the confinement effect of the PVC pipe decreased by the increment of the column diameter and compressive strength of the concrete...