Uniform cooling of a flat surface by an optimized array of turbulent impinging air jets

, Article Heat Transfer Engineering ; Volume 40, Issue 20 , 2019 , Pages 1750-1761 ; 01457632 (ISSN) Sedighi, E ; Mazloom, A ; Hakkaki Fard, A ; Sharif University of Technology

Taylor and Francis Ltd 2019

Abstract

The aim of this study is to investigate the uniform cooling of a hot isothermal heated target surface, using four turbulent impinging air jets. Eight parameters including the width of jets, the space between the inner jets, the space between inner and outer jets, the distance of jets from the plate, the impingement angle of jets, and the overall volumetric flow rate of the cooling air per unit depth of the nozzle are considered as design variables. The normalized standard deviation of the local Nusselt number from the desired Nusselt number is considered as the objective function. An optimization algorithm based on pattern search method is utilized to obtain the optimum array of the jets....

Numerical and experimental investigation of flat-plate pulsating heat pipes with extra branches in the evaporator section

, Article International Journal of Heat and Mass Transfer ; Volume 126 , 2018 , Pages 431-441 ; 00179310 (ISSN) Sedighi, E ; Amarloo, A ; Shafii, B ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

In addition to some approaches such as changing the working fluid or number of turns in a flat-plate pulsating heat pipe (FP-PHP), geometrical changes are also appealing for enhancing the thermal performance of this type of heat pipes. The main idea of this investigation is to increase heat transfer rate by increasing flow circulation of working fluid. By placing additional branches in the evaporator section, secondary bubble pumps were created which improved the circulation of fluid inside the FP-PHP. In order to investigate the impact of these additional branches, two similar four-turn aluminum FP-PHPs were fabricated. One of them was the conventional FP-PHP and the other had four...

Experimental investigation of the thermal characteristics of single-turn pulsating heat pipes with an extra branch

, Article International Journal of Thermal Sciences ; Volume 134 , 2018 , Pages 258-268 ; 12900729 (ISSN) Sedighi, E ; Amarloo, A ; Shafii, M. B ; Sharif University of Technology

Elsevier Masson SAS 2018

Abstract

In addition to some approaches such as changing the working fluid or number of turns in a pulsating heat pipe (PHP), geometrical changes are also appealing for enhancing the thermal performance of this type of heat pipes. The main idea of this investigation is to increase heat transfer rate by increasing flow circulation of working fluid. By placing an additional branch in the evaporator section, a secondary bubble pump was created which improved the circulation of fluid inside PHP. In order to investigate the impact of this additional branch, two similar one-turn copper heat pipes were fabricated. One of them was the conventional PHP and the other had an additional branch and is named...

A critical review of bioceramics for magnetic hyperthermia

, Article Journal of the American Ceramic Society ; 2021 ; 00027820 (ISSN) Sedighi, O ; Alaghmandfard, A ; Montazerian, M ; Baino, F ; Sharif University of Technology

Blackwell Publishing Inc 2021

Abstract

Magnetic hyperthermia (HT) using biocompatible ceramics is a ground-breaking, competent, and safe thermo-therapeutic strategy for cancer treatment. The magnetic properties of bioceramics, along with their structure and synthesis parameters, are responsible for the controlled heating of malignant tumors and are the key to clinical success. After providing a brief overview of magnetism and its significance in biomedicine, this review deals with materials selection and synthesis methods of bioceramics/glasses used for HT. Relevant research carried out on promising bioceramics for magnetic HT, with a focus on their size, shape, surface functionalization, magnetic field parameters, and in...

A critical review of bioceramics for magnetic hyperthermia

, Article Journal of the American Ceramic Society ; Volume 105, Issue 3 , 2022 , Pages 1723-1747 ; 00027820 (ISSN) Sedighi, O ; Alaghmandfard, A ; Montazerian, M ; Baino, F ; Sharif University of Technology

John Wiley and Sons Inc 2022

Abstract

Magnetic hyperthermia (HT) using biocompatible ceramics is a ground-breaking, competent, and safe thermo-therapeutic strategy for cancer treatment. The magnetic properties of bioceramics, along with their structure and synthesis parameters, are responsible for the controlled heating of malignant tumors and are the key to clinical success. After providing a brief overview of magnetism and its significance in biomedicine, this review deals with materials selection and synthesis methods of bioceramics/glasses used for HT. Relevant research carried out on promising bioceramics for magnetic HT, with a focus on their size, shape, surface functionalization, magnetic field parameters, and in...

A 1.5V 150MS/s current-mode sample-and-hold circuit

, Article 2005 European Conference on Circuit Theory and Design, Cork, 28 August 2005 through 2 September 2005 ; Volume 2 , 2005 , Pages 91-94 ; 0780390660 (ISBN); 9780780390669 (ISBN) Sedighi, B ; Rajaee, O ; Jahanian, A ; Bakhtiar, M. S ; Sharif University of Technology

2005

Abstract

A high-speed current-mode sample-and-hold circuit is presented. This circuit allows for high sampling speed together with high linearity and precision. The sample-and-hold circuit has been designed and simulated in standard 0.18μm CMOS technology with 1.5V supply voltage. It is capable of operation with sampling frequency of 150MHz (300MHz using double sampling technique) for 12-bit accuracy using 3.7mW power

Evaluating two Model-Free data Interpertation Method for Measurments that are Influenced by Noise and Environmental Variations

, M.Sc. Thesis Sharif University of Technology Sedighi, Sasan (Author) ; Abedian, Ali (Supervisor)

Abstract

Interpreting data of infrastructures monitored to detect damage of a structural is one of the most challenging issues of structural health monitoring (SHM). Especially, when environmental factors such as temperature, wind and humidity affect the data and the situation become more complicated. In this study, two methods of analysis free model of moving principal components analysis (MPCA) and robust regression analysis (RRA) have recently been considered for monitoring infrastructures compared with a variety of methods of data interpretation and results are presented. In this study, the performance of different ways in different loading conditions and arrangement of sensors have been...

Application of Machine Learning Algorithms on Railway Track Deterioration Modeling

, M.Sc. Thesis Sharif University of Technology Sedighi, Alireza (Author) ; Shafahi, Yosef (Supervisor)

Abstract

The vital and influential role of railways in the socio-economic growth and development of countries, along with the high costs of rehabilitation and maintenance of its infrastructure, has made the existence of a comprehensive maintenance management system a necessity to not only elevate the level of service, reliability, and safety but also to minimize such repair costs. Accurate modeling of track deterioration is essential as one of the components of such systems.In this study, a large database from outputs of EM120, track recording machine, was provided for the years 2009 to 2018 and for all 18 railway zones of Iranian Railways (approximately 13,000 km railway track and 80 GB of data)....

Ferrofluid droplet manipulation using an adjustable alternating magnetic field

, Article Sensors and Actuators, A: Physical ; Volume 301 , 2020 Bijarchi, M. A ; Favakeh, A ; Sedighi, E ; Shafii, M. B ; Sharif University of Technology

Elsevier B.V 2020

Abstract

Magnetically actuated droplet manipulation offers a promising tool for biomedical and engineering applications, such as drug delivery, biochemistry, sample handling in lab-on-chip devices and tissue engineering. In this study, characteristics of an adjustable alternating magnetic field generated by a magnetic coil for droplet manipulation was investigated which enables more control on droplet transport, and it can be considered as a suitable alternative for moving magnets or an array of micro-coils. By adjusting the magnetic flux density, the duty cycle and applied magnetic frequency, the manipulation of water-based ferrofluid droplets with a bio-compatible surfactant for different volumes...

Switched-resistor: A new family of sampled-data circuits

, Article AEU - International Journal of Electronics and Communications ; Volume 63, Issue 5 , 2009 , Pages 366-373 ; 14348411 (ISSN) Sedighi, B ; Bakhtiar, M. S ; Sharif University of Technology

2009

Abstract

This paper introduces "switched-resistor" circuits as a new family of current-mode sampled-data circuits with improved accuracy and linearity. Advantages of the switched-resistor circuits for high-speed and low-voltage applications are demonstrated. A switched-resistor biquad band-pass filter with a quality factor of 10 and clock frequency of 100 MHz, fabricated in a 0.18 μ m CMOS process, is also presented. The filter consumes 9 mW from 1.8 V supply. © 2008 Elsevier GmbH. All rights reserved

Variable gain current mirror for high-speed applications

, Article IEICE Electronics Express ; Volume 4, Issue 8 , 2007 , Pages 277-281 ; 13492543 (ISSN) Sedighi, B ; Bakhtiar, M. S ; Sharif University of Technology

2007

Abstract

This paper presents a new high speed current mirror with continuous gain adjustment. Based on this current mirror, a variable gain current amplifier is designed in 0.18μm CMOS technology. The current gain of the amplifier can be continuously varied from 0 dB to 20 dB while the bandwidth of the circuit remains above 1.00 MHz. The circuit consumes 0.9 mW from 1.5V supply. © IEICE 2007

An 8-bit 300MS/S switched-current pipeline ADC in 0.18μm CMOS

, Article 2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007, New Orleans, LA, 27 May 2007 through 30 May 2007 ; 2007 , Pages 1481-1484 ; 02714310 (ISSN) Sedighi, B ; Sharif Bakhtiar, M ; Sharif University of Technology

2007

Abstract

In this paper, capabilities of switched-current (SI) circuits are utilized to design a high-speed A/D converter. New methods to improve the performance of the SI circuits are introduced. An 8-bit 300MS/s pipeline ADC is design in 0.18um CMOS technology and an ENOB of 7.3b is obtained from simulations. The ADC consumes 40mW from a 1.8V supply. © 2007 IEEE

A new high-speed class-AB current-mode circuit

, Article 2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007, New Orleans, LA, 27 May 2007 through 30 May 2007 ; 2007 , Pages 717-720 ; 02714310 (ISSN) Sedighi, B ; Bakhtiar, M. S ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2007

Abstract

this paper presents a new class AB circuit for current-mode signal processing. The proposed circuit provides high-dynamic range, low distortion and accurate definition of quiescent current and it is well suited for high-speed applications. A third-order low-pass filter with a cutoff frequency of 200MHz and 51dB dynamic range is also presented. The Alter consumes 2.7mW from 1.8V supply. © 2007 IEEE

An 8-bit switched-resistor pipeline ADC

, Article 2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007, New Orleans, LA, 27 May 2007 through 30 May 2007 ; 2007 , Pages 1963-1966 ; 02714310 (ISSN) Sedighi, B ; Sharif Bakhtiar, M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2007

Abstract

In this paper a new technique called switched-resistor is used as an alternative to switched-capacitor circuits in a low-voltage low-power high-speed A/D converter. Simulation results for an 8-bit 150MS/s pipeline ADC are presented. This converter consumes 20mW from a 1.8V supply and provides an ENOB of 7.5bit. © 2007 IEEE

A 1.5V 60MS/s sampled-data filter in 0.18μm CMOS

, Article 2005 European Conference on Circuit Theory and Design, Cork, 28 August 2005 through 2 September 2005 ; Volume 2 , 2005 , Pages 95-98 ; 0780390660 (ISBN); 9780780390669 (ISBN) Sedighi, B ; Bakhtiar, M. S ; Sharif University of Technology

2005

Abstract

A new family of sampled-data filters in which accuracy is a function of the ratio of the resistors is introduced. It is shown that this structure is suitable for low-voltage high-speed applications. A biquad filter with a quality factor of 10 and a clock frequency of 60MHz consuming only 2mW power is also presented

A new class AB current-mode circuit for low-voltage applications

, Article APCCAS 2006 - 2006 IEEE Asia Pacific Conference on Circuits and Systems, 4 December 2006 through 6 December 2006 ; 2006 , Pages 434-437 ; 1424403871 (ISBN); 9781424403875 (ISBN) Sedighi, B ; Bakhtiar, M. S ; Sharif University of Technology

2006

Abstract

This paper presents a new class AB circuit for current-mode signal processing. These current mirrors are especially designed for advanced CMOS technologies and low-voltage high-speed applications. As an example two current amplifiers with a gain of 2, settling time of less than 6ns and current consumption of 500μA are designed and simulated. ©2006 IEEE

Electrophoretic Deposition of Titanium Dioxide for Fabrication of Photoanode of Dye Sensitized Solar Cell

, M.Sc. Thesis Sharif University of Technology Sedighi, Rahime (Author) ; Taghavinia, Nima (Supervisor)

Abstract

This research is focused on fabrication of TiO2 layers by electrophoretic deposition (EPD) for application as photoanode in Dye Sensitized Solar Cell (DSC). DSCs are third generation of solar cells, also known as the Grätzel cell, after its inventor Michael Grätzel. A DSC is composed of a porous layer of wide band gap semiconductor such as TiO2 and ZnO, covered with a molecular dye that absorbs sunlight, and a counter electrode contacted by a liquid redox electrolyte. Dye Sensitized semiconductor (photoanode) has important role in conversion of photon to electricity. To achieve higher efficiency, preparation of photoanode with high surface area resulted to enough dye adsorption is necessary....

The effect of parameters of equilibrium-based 3-D biomechanical models on extracted muscle synergies during isometric lumbar exertion

, Article Journal of Biomechanics ; Volume 49, Issue 6 , 2016 , Pages 967-973 ; 00219290 (ISSN) Eskandari, A. H ; Sedaghat Nejad, E ; Rashedi, E ; Sedighi, A ; Arjmand, N ; Parnianpour, M ; Sharif University of Technology

Elsevier Ltd 2016

Abstract

A hallmark of more advanced models is their higher details of trunk muscles represented by a larger number of muscles. The question is if in reality we control these muscles individually as independent agents or we control groups of them called "synergy". To address this, we employed a 3-D biomechanical model of the spine with 18 trunk muscles that satisfied equilibrium conditions at L4/5, with different cost functions. The solutions of several 2-D and 3-D tasks were arranged in a data matrix and the synergies were computed by using non-negative matrix factorization (NMF) algorithms. Variance accounted for (VAF) was used to evaluate the number of synergies that emerged by the analysis, which...

Solution of the falkner-skan equation for wedge by adomian decomposition method

, Article Communications in Nonlinear Science and Numerical Simulation ; Volume 14, Issue 3 , 2009 , Pages 724-733 ; 10075704 (ISSN) Alizadeh, E ; Farhadi, M ; Sedighi, K ; Ebrahimi Kebria, H. R ; Ghafourian, A ; Sharif University of Technology

2009

Abstract

The Adomian Decomposition Method is employed in the solution of the two dimensional laminar boundary layer of Falkner-Skan equation for wedge. This work aims at the solution of momentum equation in the case of accelerated flow and decelerated flow with separation. The Adomian Decomposition Method is provided an analytical solution in the form of an infinite power series. The effect of Adomian polynomials terms is considered on accuracy of the results. The velocity profiles in boundary layer are obtained. Results show a good accuracy compared to the exact solution. © 2007 Elsevier B.V. All rights reserved

Vapor assisted deposition of alkaline doped perovskites: Pure phase formation of CsxMA1−xPbI3

, Article Electrochimica Acta ; Volume 259 , 2018 , Pages 485-491 ; 00134686 (ISSN) Sedighi, R ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

Alkaline doping (Cs, Rb) in CH3NH3PbI3 (MAPbI3) is known to enhance the stability of perovskite solar cells. The films are usually deposited using anti-solvent method, which is tricky and not applicable for large scale deposition. Besides, in case of CsxMA1−xPbI3 the amount of Cs must be carefully controlled to prevent CsI phase formation. Herein, we report an atmospheric pressure vapor assisted solution process (AP-VASP) for the growth of Cs doped MAPbI3 perovskite films that features highly uniform morphology, pin-hole free films, large grain size, as well as being scalable. The CsxMA1−xPbI3 films are formed by the reaction of Cs doped PbI2 films with MAI vapor in a simple oven. We...