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    Minimization of Non-repeatable Runout (NRRO) in High-Speed Spindle Bearings

    , Article SAE 2021 Automotive Technical Papers, WONLYAUTO 2021, 1 January 2021 ; Issue 2021 , 2021 ; 01487191 (ISSN) Farahani, M. R ; Khodaygan, S ; Sharif University of Technology
    SAE International  2021
    The production with high quality at the lowest production time can be a key means to success in the competitive environment of manufacturing companies. Therefore, in recent years, the need for extra precise and high-speed machine tools has been impressively increased in manufacturing applications. One of the main sources of errors in the motion of high-speed spindles is the occurrence of non-repetitive runouts (NRRO) in the bearing. The NRRO can be caused by some factors such as the form of balls, the waviness of rings, the number of balls, and the permutation of one or two balls in the ball bearing. In this paper, a Taguchi-based approach is proposed for the optimal design of high-speed... 

    Machine learning approach for carrier surface design in carrier-based dry powder inhalation

    , Article Computers and Chemical Engineering ; Volume 151 , 2021 ; 00981354 (ISSN) Kazemzadeh Farizhandi, A. A ; Alishiri, M ; Lau, R ; Sharif University of Technology
    Elsevier Ltd  2021
    In this study, a machine learning approach was applied to evaluate the impact of operating and design variables on dry powder inhalation efficiency. Emitted dose and fine particle fraction data were extracted from the literature for a variety of drug and carrier combinations. Carrier surface properties are obtained by image analysis of SEM images reported. Models combining artificial neural network and genetic algorithm were developed to determine the emitted dose and fine particle fraction. Design strategies for the carrier surface were also proposed to enhance the fine particle fractions. © 2021 Elsevier Ltd  

    A system-level design method for RF receiver front-end with low power consumption

    , Article Analog Integrated Circuits and Signal Processing ; 2021 ; 09251030 (ISSN) Fazel, Z ; Atarodi, M ; Sadughi, S ; Sharif University of Technology
    Springer  2021
    Due to wireless communication’s rapid growth, the need for low power integrated transceivers is increasing. The receiver power is a major limiting factor, and the radio frequency (RF) front-end is often its significant power consuming part. Therefore, system-level design in which the overall specifications are distributed among RF front-end building blocks such that the minimum total power is consumed is crucial. A complete system-level design method for a low power RF front-end is presented in this paper. For this purpose, the performance of each block is modeled by its current and overdrive voltage. An analytical associated with a search-based optimization technique is employed to derive... 

    Robust performance in parametric control system design with application to power systems

    , Article IEEE Transactions on Industrial Electronics ; Volume 68, Issue 3 , 2021 , Pages 2400-2407 ; 02780046 (ISSN) Firouzbahrami, M ; Nobakhti, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    This article deals with the problem of robust low-order controller design for systems with multimodel representations. Such models are frequently used for the description of nonlinear and complex industrial power systems over an operating profile. We first develop a generalized complex extension of convex direction based on the interpolation and edge theorems. Subsequently, for plant models with parametric-type uncertainty, new vertex results related to robustness margins and system performance are derived. Based on this, new tools to design robust low-order controllers for such systems are presented. © 1982-2012 IEEE  

    Frequency characteristics of a viscoelastic graphene nanoplatelet–reinforced composite circular microplate

    , Article JVC/Journal of Vibration and Control ; Volume 27, Issue 1-2 , 2021 , Pages 101-118 ; 10775463 (ISSN) Ghabussi, A ; Habibi, M ; NoormohammadiArani, O ; Shavalipour, A ; Moayedi, H ; Safarpour, H ; Sharif University of Technology
    SAGE Publications Inc  2021
    This is the first research on the frequency analysis of a graphene nanoplatelet composite circular microplate in the framework of a numerical-based generalized differential quadrature method. Stresses and strains are obtained using the higher order shear deformation theory. The microstructure is surrounded by a viscoelastic foundation. Rule of the mixture is used to obtain varying mass density and Poisson’s ratio, whereas the module of elasticity is computed by a modified Halpin–Tsai model. Governing equations and boundary conditions of the graphene nanoplatelet composite circular microplate are obtained by implementing Hamilton’s principle. The results show that outer to inner radius ratio... 

    Free vibration analysis of an electro-elastic GPLRC cylindrical shell surrounded by viscoelastic foundation using modified length-couple stress parameter

    , Article Mechanics Based Design of Structures and Machines ; Volume 49, Issue 5 , 2021 , Pages 738-762 ; 15397734 (ISSN) Ghabussi, A ; Ashrafi, N ; Shavalipour, A ; Hosseinpour, A ; Habibi, M ; Moayedi, H ; Babaei, B ; Safarpour, H ; Sharif University of Technology
    Bellwether Publishing, Ltd  2021
    Due to the rapid development of process manufacturing, composite materials with graphene-reinforcement have obtained commercially notices in promoted engineering applications. For this regard, vibrational characteristics of a cylindrical nanoshell reinforced by graphene nanoplatelets (GPL) and coupled with piezoelectric actuator (PIAC) is investigated. Also, the nanostructure is embedded in a viscoelastic medium. The material properties of piece-wise graphene-reinforced composite (GPLRC) are assumed to be graded in the thickness direction of a cylindrical nanoshell and estimated through a nanomechanical model. For the first time in the current study is considering the effects of... 

    Developing a new superhydrophilic and superoleophobic poly(4-(1-vinyl-1H-imidazol-3-ium-3-yl) butane-1-sulfonate): vinyl imidazole@Perfluorooctanoic acid@SiO2 coated stainless steel mesh for highly efficient, stable, and durable oil/water separation

    , Article Journal of Coatings Technology and Research ; Volume 18, Issue 2 , 2021 , Pages 511-521 ; 15470091 (ISSN) Ghadimi, M. R ; Siavash Moakhar, R ; Amirpoor, S ; Azad, M ; Dolati, A ; Sharif University of Technology
    Springer  2021
    The design and development of efficient approaches for water–oil separation have had widespread interest. Most previously introduced techniques and materials used for development of the successful separation of oily wastewater could not answer all the desired demands, such as being efficient and environmentally and economically friendly. Therefore, in seeking a novel method capable of answering these expectations, surfaces with special wettability were introduced. A novel, reusable, and recyclable superhydrophilic and superoleophobic poly(Vsim-Vim)@PFOA@SiO2 nanocomposite-coated stainless steel mesh was synthesized through a facile preparation process. Since the most important factors of... 

    Application of endurance time method in seismic analysis of bridges

    , Article Scientia Iranica ; Volume 27, Issue 4A , 2021 , Pages 1751-1761 ; 10263098 (ISSN) Ghaffari, E ; Estekanchi, H. E ; Vafai, A ; Sharif University of Technology
    Sharif University of Technology  2021
    In this paper, the application of Endurance Time (ET) method to the seismic analysis of bridges is elaborated. ET method is a novel seismic analysis method based on time history analysis in which a structure is subjected to a predefined intensifying acceleration function. First, six concrete bridges were modeled in this study. Three Endurance Time Acceleration Functions (ETAFs) were applied to the models, and the average of responses was calculated. Next, the time history analysis was conducted using seven real accelerograms that are scaled using the method recommended by Federal Highway Administration (FHWA) to be compatible with the design spectrum of American Association of State Highway... 

    Quantifying seismic response uncertainty of electrical substation structures using endurance time method

    , Article Structures ; Volume 30 , 2021 , Pages 838-849 ; 23520124 (ISSN) Ghahremani Baghmisheh, A ; Estekanchi, H. E ; Sharif University of Technology
    Elsevier Ltd  2021
    A new procedure is proposed to quantify uncertainties involved in the seismic response of structures including ground motion and modeling variability. The advent of performance-based earthquake engineering (PBEE) and probabilistic seismic risk analysis necessitates consideration of uncertainties in predicting seismic responses. However, the high computational cost of conventional methods restricts their application to only simple numerical models. The present study employs the endurance time (ET) method concept to predict the response distribution which requires much less computational efforts than conventional methods. The proposed procedure for the quantification of record-to-record... 

    Prediction of seismic damage spectra using computational intelligence methods

    , Article Computers and Structures ; Volume 253 , 2021 ; 00457949 (ISSN) Gharehbaghi, S ; Gandomi, M ; Plevris, V ; Gandomi, A. H ; Sharif University of Technology
    Elsevier Ltd  2021
    Predicting seismic damage spectra, capturing both structural and earthquake features, is useful in performance-based seismic design and quantifying the potential seismic damage of structures. The objective of this paper is to accurately predict the seismic damage spectra using computational intelligence methods. For this purpose, an inelastic single-degree-of-freedom system subjected to a set of earthquake ground motion records is used to compute the (exact) spectral damage. The Park-Ang damage index is used to quantify the seismic damage. Both structural and earthquake features are involved in the prediction models where multi-gene genetic programming (MGGP) and artificial neural networks... 

    Investigation and modeling of energy consumption of tall office buildings in Iran’s ‘hot-arid’ and ‘cold’ climate conditions

    , Article International Journal of Low-Carbon Technologies ; Volume 16, Issue 1 , 2021 , Pages 21-34 ; 17481317 (ISSN) Ghiai, M. M ; Tabe Arjmand, J ; Mohammadi, O ; Ahmadi, M. H ; El Haj Assad, M ; Sharif University of Technology
    Oxford University Press  2021
    The construction of high-rise buildings has attracted human attention at the beginning of human civilizations’ formation. Presently, making tall buildings is considered as a necessary requirement due to the succeeding reasons: the population increase, the tendency to live in urban centers, the land utilization in the most populated centers of the cities, the need to decrease the cost of horizontal development of cities and technological advances. During the last century, issues related to environmental pollution and high energy use have affected these tall buildings. So, it is crucial to apply appropriate methods and patterns in order to adjust their environmental impacts as much as... 

    Integrated and inherently safe design and operation of a mobile power generation: Process intensification through microreactor reformer and HT-PEMFC

    , Article International Journal of Hydrogen Energy ; Volume 46, Issue 46 , 2021 , Pages 23839-23854 ; 03603199 (ISSN) Ghodba, A ; Sharifzadeh, M ; Rashtchian, D ; Sharif University of Technology
    Elsevier Ltd  2021
    In the present study, due to various advantages of process miniaturization, the integrated design and operation of a mobile power generation system consisting of a microreactor reformer and a proton exchange membrane fuel cell (PEMFC) are investigated. The hydrogen fuel is supplied through autothermal steam-reforming of methanol in a microreactor leading to a safer, as well as more efficient, and economical operation. A high-temperature polymer membrane fuel cell with external accessories is applied for power generation. Then, simulation-optimization programming is applied for simultaneously optimizing the process design and operation at the same level. The result shows that the implemented... 

    Addressing the epistemic uncertainty in seismic hazard analysis as a basis for seismic design by emphasizing the knowledge aspects and utilizing imprecise probabilities

    , Article Bulletin of Earthquake Engineering ; 2021 ; 1570761X (ISSN) Ghods, B ; Rahimzadeh Rofooei, F ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    Epistemic uncertainty in seismic hazard analysis is traditionally addressed by utilizing a logic-tree structure with subjective probabilities for branches. However, many studies have argued that probability is not a suitable choice for addressing epistemic uncertainties; in particular in addressing the background knowledge supporting the probabilities. In this regard, the application of imprecise probability (IP) is investigated. It is discussed that IP could provide a flexible tool for a more objective presentation of experts' knowledge. Moreover, the importance of addressing the strength of knowledge and surprises relative to knowledge in seismic hazard analysis along with methods to do... 

    Robust and efficient zero liquid discharge design strategy using four novel desalination systems: A comprehensive 4E assessment

    , Article Journal of Cleaner Production ; Volume 310 , 2021 ; 09596526 (ISSN) Ghofrani, I ; Moosavi, A ; Sharif University of Technology
    Elsevier Ltd  2021
    Discharging unconventional water sources having a high content of inorganic compounds is extremely destructive to the environment. In this research, four novel semi-open-air and closed-air configurations of brine-recycle humidification-dehumidification (BRHDH) systems with zero liquid discharge (ZLD) approach are presented to treat unconventional waters cost-effectively. Bubble-column humidifiers and dehumidifiers are used to have a low initial expenditure, and system multi-staging is implemented to reduce the operating expense of the configurations. The configurations are evaluated for high saline brine treatment using comprehensive energy, exergy, exergoeconomic, and exergoenvironmental... 

    An analytical method for spiral-wound heat exchanger: design and cost estimation considering temperature-dependent fluid properties

    , Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 31, Issue 1 , 2021 , Pages 471-496 ; 09615539 (ISSN) Hosseinian, S. M ; Mostafazade Abolmaali, A ; Afshin, H ; Sharif University of Technology
    Emerald Group Holdings Ltd  2021
    Purpose: Spiral-wound heat exchangers (SWHEs) are widely used in different industries. In special applications, such as cryogenic (HEs), fluid properties may significantly depend on fluid temperature. This paper aims to present an analytical method for design and rating of SWHEs considering variable fluid properties with consistent shell geometry and single-phase fluid. Design/methodology/approach: To consider variations of fluid properties, the HE is divided into identical segments, and the fluid properties are assumed to be constant in each segment. Validation of the analytical method is accomplished by using three-dimensional numerical simulation with shear stress transport k-ω model, and... 

    Optimization and modeling of Zn2SnO4 sensitivity as gas sensor for detection benzene in the air by using the response surface methodology

    , Article Journal of Saudi Chemical Society ; Volume 25, Issue 12 , 2021 ; 13196103 (ISSN) Hosseinzadeh asl, H ; Tohidi, G ; Movahedi, F ; Hassannayebi, E ; Sharif University of Technology
    Elsevier B.V  2021
    In this paper, the performance of the benzene gas detection sensor in the air is optimized by an experimental design method. So in this work, Nanostructured thin films of ZnO and Zn2SnO4 were prepared in wurtzite form via a facile atmospheric pressure chemical vapor deposition (CVD) method, using metallic zinc and tin precursors. Characterization of the gas sensor was performed by using Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and surface area analysis (using BET method). The results show that Zn2SnO4 nanowire network exhibited good sensitivity at 299 °C temperature to low concentrations (100 ppb) of Benzene which can be potentially used as a resistive gas sensor.... 

    A comprehensive comparative investigation on solar heating and cooling technologies from a thermo-economic viewpoint—A dynamic simulation

    , Article Energy Science and Engineering ; Volume 9, Issue 5 , 2021 , Pages 724-742 ; 20500505 (ISSN) Jafari Mosleh, H ; Behnam, P ; Abbasi Kamazani, M ; Mohammadi, O ; Kavian, S ; Ahmadi, P ; Rosen, M. A ; Sharif University of Technology
    John Wiley and Sons Ltd  2021
    The yearly thermo-economic performance is dynamically investigated for three solar heating and cooling systems: solar heating and absorption cooling (SHAC), solar heating and ejector cooling (SHEC), and heating and solar vapor compression cooling (HSVC). First, the effects of important design parameters on the thermo-economic performance of the systems to supply the heating and cooling loads of the building are evaluated. The systems are parametrically analyzed with the weather conditions of Tehran, Iran. The results show that the life cycle costs (LCC) of the SHAC and HSVC systems are alike and much lower than those of the SHEC system. The HSVC system exhibits the best performance from... 

    Effect of stress direction on the undrained monotonic and cyclic behavior of dense sands

    , Article Scientia Iranica ; Volume 27, Issue 2 , 2021 , Pages 551-565 ; 10263098 (ISSN) Jafarzadeh, F ; Zamanian, M ; Sharif University of Technology
    Sharif University of Technology  2021
    Geotechnical design may be unsafe if the anisotropic behavior of soil is not considered. The behavior of anisotropic materials depends on the principal stresses and their directions. A detailed experimental programme was conducted to study the e ect of stress direction on the monotonic and cyclic behavior of dense sand. A total of 20 undrained tests were performed at a constant mean con ning stress (00m), a constant intermediate principal stress ratio (b = (2 - 3)=(1 -3)), and principal stress directions (). Two ne sands, Babolsar and Toyoura, were selected as the test materials. The isotropically consolidated specimens were prepared by the wet tamping technique. The results showed that the... 

    Comprehensive hydrothermal analysis of an inclined mini-channel with fin array: by dual/multi-relaxation-time LBM and experimental process on SiO2-glycol rheological/thermal characteristics

    , Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 31, Issue 7 , 2021 , Pages 2405-2429 ; 09615539 (ISSN) Kamali, D ; Hejri, S ; Akbar, N ; Hasani Malekshah, E ; Sharif University of Technology
    Emerald Group Holdings Ltd  2021
    Purpose: The purpose of this study is to present a comprehensive hydrothermal analysis on an inclined mini-channel using numerical and experimental techniques. The fin array acts as heat source within the channel, and a wavy wall located at the top of the channel is heat sink. The side walls are insulated with curved profiles. Also, the channel is inclined with four known inclination angles. To solve the governing equations, the dual-multi-relaxation-time lattice Boltzmann method with D2Q9 and D2Q5 lattice models for flow and temperature fields is used, respectively. Also, the channel is filled with SiO2-glycol nanofluid. Design/methodology/approach: Identifying the behavior of a thermal... 

    Stability analysis for design improvement of bio-inspired flapping wings by energy method

    , Article Aerospace Science and Technology ; Volume 111 , 2021 ; 12709638 (ISSN) Kamankesh, Z ; Banazadeh, A ; Sharif University of Technology
    Elsevier Masson s.r.l  2021
    This study attempts to reach a broad understanding of the stability properties of nonlinear time-periodic flapping wing structures. Two bio-system models, Hummingbird (6DOF) and Hawkmoth (3DOF) are developed for this purpose. Initial analysis on the Hummingbird model, which is based on the Floquet theory, kinetic energy integration, and phase portrait technique, indicates lack of stability in hover flight. Kinetic energy integration is carried out on the extended model of the Hawkmoth to find the domain of attraction and increase the level of stability by varying the design parameters. Here, the hinge location of the wing, flapping amplitude, flapping frequency, and mean angle of attack are...