Quantitative Rsk Assessment and Accident Frequency Determination Based on Fuzzy Logic with Shazand Oil Refinery Accident Case Study

, M.Sc. Thesis Sharif University of Technology Javidi, Majid (Author) ; Rashtchian, Davoud (Supervisor)

Abstract

Today, Quantitative Risk Assessment (QRA) has become an efficient tool in decision making for safety and process experts. To assess the risk of any accident scenario, it is necessary that the probability of that event be determined in addition to estimating the probable consequences. Event tree and fault tree analysis are known to be the standard tools for calculating the frequency of incident outcomes.
In this research, a new method based on Markov chin and Fuzzy theory is presented to estimate the occurrence probability of events. A one of important parameter which has sufficient effect on probability of incident frequency, is inspection and maintenance interval. in this research...

Short-Circuit Failure Detection in Series-Connected IGBTs for Reliability Improvements

, M.Sc. Thesis Sharif University of Technology Javidi, Pourya (Author) ; Kaboli, Shahriyar (Supervisor)

Abstract

In high-voltage power electronics systems where the supply voltage exceeds the maximum voltage these devices can withstand, series-connected IGBTs with TO-247 packaging and simultaneous gate command circuitry are used to create a high-voltage switch with an on and off time equivalent to a single IGBT. By considering voltage protection circuits for the series IGBTs, the large supply voltage is approximately evenly divided among the series switches. The resulting high-voltage switch has smaller conduction and switching losses compared to single high-voltage switches, has a lower finished price, and its turn-on time is much shorter due to their smaller gate-emitter junction capacitance...

Inherently safe and economically optimal design using multi-objective optimization: The case of a refrigeration cycle

, Article Process Safety and Environmental Protection ; Volume 104 , 2016 , Pages 254-267 ; 09575820 (ISSN) Eini, S ; Shahhosseini, H. R ; Javidi, M ; Sharifzadeh, M ; Rashtchian, D ; Sharif University of Technology

Institution of Chemical Engineers 2016

Abstract

The economic viability of industrial processes strongly depends on their safe and reliable operation. The method of inherent safe process design enables systematic consideration of safety measures in order to ensure process safe operation at the early stages of process design. The challenge is that the economic measures that are often considered for the design of industrial processes are often incommensurable with the safety measures. In the present research, a novel framework is proposed in which the safety criteria are quantified based on consequence modeling and aggregated with the economic performance using multi-objective optimization programming. The developed methodology was applied...

Dielectrophoretic interaction of two particles in a uniform electric field

, Article Microsystem Technologies ; Volume 25, Issue 7 , 2019 , Pages 2699-2711 ; 09467076 (ISSN) Javidi, R ; Moghimi Zand, M ; Dastani, K ; Sharif University of Technology

Springer Verlag 2019

Abstract

The local electric field distorsion induced by a dielectric particle leads to particle–particle interactions and assembly which is very interesting for their useful applications on microfluidic devices. Particles behavior becomes more complicated if several particles interact at the same time. This paper presents a comprehensive numerical analysis of the assembly and particle–particle interactions for two similar and dissimilar dielectric particles immersed in a dielectric fluid using the immersed interface method based on two-dimensional direct-current dielectrophoresis. The immersed interface method is a finite-difference (or finite element) based numerical method which its key advantage...

Effect of input voltage frequency on the distribution of electrical stresses on the cell surface based on single-cell dielectrophoresis analysis

, Article Scientific Reports ; Volume 10, Issue 1 , 2020 Dastani, K ; Moghimi Zand, M ; Kavand, H ; Javidi, R ; Hadi, A ; Valadkhani, Z ; Renaud, P ; Sharif University of Technology

Nature Research 2020

Abstract

Electroporation is defined as cell membrane permeabilization under the application of electric fields. The mechanism of hydrophilic pore formation is not yet well understood. When cells are exposed to electric fields, electrical stresses act on their surfaces. These electrical stresses play a crucial role in cell membrane structural changes, which lead to cell permeabilization. These electrical stresses depend on the dielectric properties of the cell, buffer solution, and the applied electric field characteristics. In the current study, the effect of electric field frequency on the electrical stresses distribution on the cell surface and cell deformation is numerically and experimentally...

A multivariable model for estimation of vapor cloud explosion occurrence possibility based on a Fuzzy logic approach for flammable materials

, Article Journal of Loss Prevention in the Process Industries ; Volume 33 , January , 2015 , Pages 140-150 ; 09504230 (ISSN) Javidi, M ; Abdolhamidzadeh, B ; Reniers, G ; Rashtchian, D ; Sharif University of Technology

Elsevier Ltd 2015

Abstract

In this paper, a new method based on Fuzzy theory is presented to estimate the occurrence possibility of vapor cloud explosion (VCE) of flammable materials. This new method helps the analyst to overcome some uncertainties associated with estimating VCE possibility with the Event Tree (ET) technique. In this multi-variable model, the physical properties of the released material and the characteristics of the surrounding environment are used as the parameters specifying the occurrence possibility of intermediate events leading to a VCE. Factors such as area classification, degree of congestion of a plant and release rate are notably affecting the output results. Moreover, the proposed method...

A fast optimization method for extension of depth-of-field in three-dimensional task-specific imaging systems

, Article IEEE/OSA Journal of Display Technology ; Volume 6, Issue 10 , August , 2010 , Pages 412-421 ; 1551319X (ISSN) Bagheri, S ; Kavehvash, Z ; Mehrany, K ; Javidi, B ; Sharif University of Technology

2010

Abstract

In this paper, we present a novel approach to generate images of extended depth-of-field (DOF) to support realization of three-dimensional (3D) imaging systems such as integral imaging. In our approach in extending the DOF, we take advantage of the spatial frequency spectrum of the object specific to the task in hand. The pupil function is thus engineered in such a fashion that the modulation transfer function (MTF) is maximized only in these selected spatial frequencies. We extract these high energy spatial frequencies using the principal component analysis (PCA) method. Moreover, given the need for many pupil function engineering steps in 3D imaging systems, we have constructed an...

Design and Implementation of a Distributed System for Energy Management in a Hybrid-Energy Building

, M.Sc. Thesis Sharif University of Technology Javidi Mostafapoor Boshrooyeh, Hamed (Author) ; Goudarzi, Maziar (Supervisor)

Abstract

Solar panels are still rather expensive equipments. At current electricity prices, it takes several years to return the investment made to install them in a household. Smarter use of their produced energy can help reduce this break-even time, and hence, would motivate more households to be willing to install and use them which would finally result in a more sustainable society with less reliance on fossil fuels. Electricity prices usually differ at different times of day with the common, but unfortunate, property that the price is maximized at evenings when the solar energy production is minimal or non-existent while at the peak production of the solar panels, i.e., around noon, the price is...

, M.Sc. Thesis Sharif University of Technology Javidi Sofiani, Mahyar (Author) ; Ramezani Saadat, Ahmad (Supervisor)

Abstract

Polymer flooding can yield considerable increase in percentage recovery. However, there are limitations with the existing polymer flooding technology, such as thermal, mechanical, bacterial degradation, surface absorption and undesirable plugging. A novel nanocore shell structure of polyacrylamide and polystyrene designed and prepared to intellectually control mobility ratio in oil reservoirs and overcome weakness and limitations of classical polymer flooding. Polyacrylamide particles have been obtained using spray drying of dilute solution of polyacrylamide. Then, polystyrene shell has been produced on polyacryamide particles by in-situ polymerization of styrene monomer in hydrophobic...

Conductive nerve conduit with piezoelectric properties for enhanced PC12 differentiation

, Article Scientific Reports ; Volume 13, Issue 1 , 2023 ; 20452322 (ISSN) Javidi, H ; Ramazani Saadatabadi, A ; Sadrnezhaad, S. K ; Najmoddin, N ; Sharif University of Technology

Nature Research 2023

Abstract

Restoration of nerve tissue remains highly challenging, mainly due to the limited regeneration capacity of the nervous system and the development of fibrosis. This limitation necessitates designing new nerve guidance channel to promote nerve repairing. In this study, we developed a novel core/shell conduit to induce PC12 differentiation. Co-electrospinning method was utilized to produce a fibrous shell containing polycaprolactone/polyvinylidene fluoride PCL/PVDF, gelatin and polyaniline/graphene (PAG) nanocomposite. The core section of the conduit was filled with chitosan–gelatin hydrogel containing PAG and ZnO nanoparticles. Such conduit shows antibacterial activity, electrical conductivity...

A data analytics framework for reliable bus arrival time prediction using artificial neural networks

, Article International Journal of Data Science and Analytics ; 2023 ; 2364415X (ISSN) Hassannayebi, E ; Farjad, A ; Azadnia, A ; Javidi, M ; Chunduri, R ; Sharif University of Technology

Springer Science and Business Media Deutschland GmbH 2023

Abstract

The analysis of extensive vehicle location data in an urban bus system requires an efficient data-driven method so that its output can be used to improve both the information and operational reliabilities of the bus transit services. This research aims to design and implement an integrated model for forecasting bus arrival times using artificial intelligence techniques. The novelty of the research lies in developing an integrated predictive model based on a neural network computing framework to improve the results of fleet arrival forecasting models based on the estimation of travel time reliability. To validate the prediction model, extensive experiments are conducted to compare the...

An energy-efficient multi-sensor scheduling mechanism with QoS support for WBANs

, Article IEEE Wireless Communications and Networking Conference, WCNC ; 2014 , pp. 1703-1708 ; ISSN: 15253511 Omidvar, H ; Ashtiani, F ; Javidi, T ; Nasiri-Kenari, M ; Vahdat, B. V ; Sharif University of Technology

2014

Abstract

In wireless body area networks (WBANs) it is necessary to devise an energy-efficient MAC scheduling mechanism which is capable of meeting strict QoS requirements. In this paper, special characteristics of WBAN channels, namely, the slow fading, the periodicity of fading, and the correlation among the channels have been exploited to formulate the sensor scheduling problem as a partially observable Markov decision problem (POMDP). Specific algorithms based on value iteration and pruning have been proposed in order to reduce the computational burden associated with the corresponding POMDP. The proposed scheduling mechanism is compared against a TDMA scheduling for a three-sensor network, and an...

Extension of depth of field using amplitude modulation of the pupil function for bio-imaging

, Article Proceedings of SPIE - The International Society for Optical Engineering, 6 April 2010 through 8 April 2010 ; Volume 7690 , May , 2010 ; 0277786X (ISSN) ; 9780819481542 (ISBN) Kavehvash, Z ; Bagheri, S ; Mehrany, K ; Javidi, B ; Sanchez, E ; Martinez Corral, M ; Sharif University of Technology

2010

Abstract

In this paper we present a novel approach to generate images of extended depth of field (DOF) without compromising the lateral resolution to support realization of three-dimensional imaging systems such as integral imaging. In our approach in extending DOF, we take advantage of the spatial frequency spectrum of the object specific to the task in hand. The pupil function is thus engineered in such a fashion that the modulation transfer function (MTF) is maximized only in these selected spatial frequencies. We extract these high energy spatial frequencies using PCA method. The advantage of our approach is illustrated using an amplitude modulation and a phase modulation example. In these...

Metabolic profiling of seminal plasma from teratozoospermia patients

, Article Journal of Pharmaceutical and Biomedical Analysis ; Volume 178 , January , 2020 Mehrparvar, B ; Chashmniam, S ; Nobakht, F ; Amini, M ; Javidi, A ; Minai Tehrani, A ; Arjmand, B ; Gilany, K ; Sharif University of Technology

Elsevier B. V 2020

Abstract

Teratozoospermia is one of conditions that can cause male infertility. The mechanism of teratozoospermia remains unclear. The knowledge of the metabolites in human seminal plasma (HSP) is meaningful for the pathological study of teratozoospermia. Analysis of changed metabolites in HSP can help understand the cellular mechanism, find the novel biomarkers and subsequently design a diagnosis test. In this study, the analysis of samples performed by proton nuclear magnetic resonance spectroscopy (1H NMR spectroscopy) to identify the various metabolites, with the aim of finding metabolic profiles and biomarkers related to male infertility. Eighteen de-regulated metabolites were identified in...

Nonlinear interstory drift contours for idealized forward directivity pulses using "modified fish-bone" models

, Article Advances in Structural Engineering ; Volume 18, Issue 5 , May , 2015 , Pages 603-627 ; 13694332 (ISSN) Khalo, A. R ; Khosravi, H ; Jamnani, H. H ; Sharif University of Technology

Multi-Science Publishing Co. Ltd 2015

Abstract

Four 5-, 10-, 20- and 30-story moment frames, representing low-, mid-, and two high-rise structures, were subjected to a great number of idealized directivity pulses. The amplitudes and periods of pulses vary from 0.02 g to 1.0 g and 0.5 to 12 sec, respectively. Over 1400 nonlinear dynamic analyses of low- to high-rise moment frames were performed which were feasible through using modified fish-bone model. The distribution of interstory drift along the height was studied and two applied contours were proposed: (i) the maximum interstory drift contour, and (ii) the critical story contour. These contours were demonstrated versus the ratio of natural period of the structure to the pulse period...

Analysis of singularities of a 3DOF parallel manipulator based on a novel geometrical method

, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) Pendar, H ; Sadeghian, H ; Roozbehani, H ; Zohoor, H ; Sharif University of Technology

2006

Abstract

In this article singular points of a parallel manipulator are obtained based on a novel geometrical method. Here we introduce the constrained plain method (CPM) and some of its application in parallel mechanism. Given the definition of constraint plane (CP) and infinite constraint plane (ICP) the dependency conditions of constraints is achieved with the use of a new theorem based on the Ceva geometrical theorem. The direction of angular velocity of a body is achieved by having three ICPs with the use of another theorem. Finally, with the use of the above two novel theorems singularities of the 3UPF_PU mechanism are obtained. It should be emphasized that this method is completely geometrical,...

Melting enthalpy and entropy of freestanding metallic nanoparticles based on cohesive energy and average coordination number

, Article Journal of Physical Chemistry C ; Volume 115, Issue 35 , August , 2011 , Pages 17310-17313 ; 19327447 (ISSN) Omid, H ; Delavari H., H ; Madaah Hosseini, H. R ; Sharif University of Technology

2011

Abstract

An analytical model is proposed to study the effect of particle size on melting enthalpy and entropy of metallic nanoparticles (NPs). The Mott's and Regel's equations for melting entropy in the combination of core average coordination number (CAC) and surface average coordination number (SAC) of freestanding NPs are considered. Clusters of icosahedral (IC), body centered cubic (BCC), and body centered tetragonal (BCT) structure without any vacancies and defects are modeled. Using the variable coordination number made this model to be in good agreement with experimental and molecular dynamic (MD) results of different crystal structures. The model predicts melting entropy and enthalpy of...

On the temperature and residual stress field during grinding

, Article WCE 2010 - World Congress on Engineering 2010, 30 June 2010 through 2 July 2010 ; Volume 2 , 2010 , Pages 1196-1200 ; 9789881821072 (ISBN) H-Gangaraj, S. M ; Farrahi, G. H ; Ghadbeigi, H ; Sharif University of Technology

2010

Abstract

Grinding is widely used for manufacturing of components that require fine surface finish and good dimensional accuracy. In this study a thermo-mechanical finite element analysis is conducted to find out how grinding parameters can affect temperature and residual stress distribution in the workpiece. Results of parametric study presented in this work indicate, by carefully selecting the grinding parameters, minimum thermal and mechanical damage can be achieved. Higher workpiece velocities produce higher surface residual stress. By increasing depths of cut, depth of tensile residual stresses increases. Convection heat coefficient does not have any considerable effect on surface residual stress...

A new lattic LP-based post filter for adaptive noise cancellers in mobile and vehicular applications

, Article Proceedings of the 8th IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2008, 16 December 2008 through 19 December 2008, Sarajevo ; 2008 , Pages 407-412 ; 9781424435555 (ISBN) Khorram, S ; Sameti, H ; Veisi, H ; Abutalebi, H. R ; Sharif University of Technology

2008

Abstract

Adaptive Noise Cancellation (ANC) is a well-known technique for background noise reduction in automobile and vehicular environments. The noise fields in automobile and other vehicle interior obey the diffuse noise field model closely. On the other hand, the ANC does not provide sufficient noise reduction in the diffuse noise fields. In this paper, a new multistage post-filter is designed for ANC as a solution to diffuse noise conditions. The designed post-filter is a single channel Linear Prediction (LP) based speech enhancement system. The LP is performed by an adaptive lattice filter and attempts to extract speech components by using intermediate ANC signals. The post-filter has no...

Finite element analysis of shot-peening effect on fretting fatigue parameters

, Article Tribology International ; Volume 44, Issue 11 , 2011 , Pages 1583-1588 ; 0301679X (ISSN) H-Gangaraj, S. M ; Alvandi Tabrizi, Y ; Farrahi, G. H ; Majzoobi, G. H ; Ghadbeigi, H ; Sharif University of Technology

2011

Abstract

Shot peening is widely used to improve the fretting fatigue strength of critical surfaces. Fretting fatigue occurs in contacting parts that are subjected to fluctuating loads and sliding movements at the same time. This paper presents a sequential finite element simulation to investigate the shot peening effects on normal stress, shear stress, bulk stress and slip amplitude, which are considered to be the controlling parameters of fretting damage. The results demonstrated that among the modifications related to shot peening, compressive residual stress has a dominant effect on the fretting parameters