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Prognostic of rolling element bearings based on early-stage developing faults
, Article International Journal of COMADEM ; Volume 23, Issue 1 , February , 2020 , Pages 55-60 ; Behzad, M ; Ghodrati, B ; Khodaygan, S
COMADEM International
2020
Abstract
Rolling-element bearing (REB) failure is one of the general damages in rotating machinery. In this manner, the correct prediction of remaining useful life (RUL) of REB is a crucial challenge to move forward the unwavering quality of the machines. One of the main difficulties in implementing data-driven methods for RUL prediction is to choose proper features that represent real damage progression. In this article, by using the outcomes of frequency analysis through the Envelope method, the initiated/existed defects on the ball bearings are identified. Also, new features based on developing faults of ball bearings is recommended to estimate RUL. Early-stage faults in ball bearings usually...
Prognostic of rolling element bearings based on early-stage developing faults
, Article 2nd World Congress on Condition Monitoring, WCCM 2019, 2 December 2019 through 5 December 2019 ; 2021 , Pages 333-342 ; 21954356 (ISSN); 9789811591983 (ISBN) ; Behzad, M ; Khodaygan, S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Rolling element bearing (REB) failure is one of the general damages in rotating machinery. In this manner, the correct prediction of remaining useful life (RUL) of REB is a crucial challenge to move forward the unwavering quality of the machines. One of the main difficulties in implementing data-driven methods for RUL prediction is to choose proper features that represent real damage progression. In this article, by using the outcomes of frequency analysis through the envelope method, the initiated/existed defects on the ball bearings are identified. Also, new features based on developing faults of ball bearings are recommended to estimate RUL. Early-stage faults in ball bearings usually...
Experimental study of rolling element bearing failure pattern based on vibration growth process
, Article Proceedings of the 29th European Safety and Reliability Conference, ESREL 2019, 22 September 2019 through 26 September 2019 ; 2020 , Pages 1179-1186 ; Behzad, M ; Ghodrati, B ; Taghizadeh Vahed, A ; Sharif University of Technology
Research Publishing Services
2020
Abstract
Rolling-element bearing (REB) Failure is one of the most common failure in rotary machines in industry. Therefore, this concern draws attention to the concept of diagnostic and the prediction of REB failure. The efficacy of vibration analysis in this area has led many researchers to focus on this topic in recent decades. Defective bearings such as fatigue, surface roughness, and corrosion can lead to disastrous accidents. Therefore, providing an algorithm for the detection and classification of bearing defects is valuable and useful. The prediction of the bearing's lifetime is important to ensure the planned production in an industrial unit. In this paper, different models for performance...
Vibration Isolation of Suspension System by Magneto-Rheological (MR)Damper
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor)
Abstract
Suspension system is one of the most influential components of vehicle in the area of stability and comfort. The suspension system is designed based on the use of the vehicle and stable characteristics. Obviously, being distant from the designed spots and applying various gates, its optimized performance is lost. Semi-active suspensions by changing their features get floating designed spots to be created and suspension system is always in optimum conditions through a suitable control. This research covers the efficacy of using damper Magneto Rheological which is called damper (MR) on the performance of vehicle suspension system in reducing vibrations. This damper is considered as a device in...
Quantum corrections in the drift-diffusion model
, Article Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers ; Volume 46, Issue 11 , 2007 , Pages 7247-7250 ; 00214922 (ISSN) ; Faez, R ; Sadoghi Yazdi, H ; Sharif University of Technology
2007
Abstract
Based on the solution of the Wigner-Boltzmann (WB) equation, quantum correction in the drift-diffusion (DD) model is proposed. The new model, which is a form of the quantum DD model, can show quantum phenomena such as tunneling and quantum repulsion. To evaluate the proposed model, potential barrier and potential wells are simulated. Simulation results show the electron tunneling through and repulsion from the potential barrier. © 2007 The Japan Society of Applied Physics
Synergy between hemagglutinin 2 (HA2) subunit of influenza fusogenic membrane glycoprotein and oncolytic Newcastle disease virus suppressed tumor growth and further enhanced by Immune checkpoint PD-1 blockade
, Article Cancer Cell International ; Volume 20, Issue 1 , August , 2020 ; Ebrahimzadeh, M. S ; Abdolalipour, E ; Yazdi, M ; Hosseini Ravandi, H ; Ghaemi, A ; Sharif University of Technology
BioMed Central Ltd
2020
Abstract
Background: Newcastle disease virus (NDV) has shown noticeable oncolytic properties, especially against cervical cancer. However, in order to improve the spread rate and oncotoxicity of the virus, employment of other therapeutic reagents would be helpful. It has been shown that some viral fusogenic membrane glycoproteins (FMGs) could facilitate viral propagation and increase the infection rate of tumor cells by oncolytic viruses. Additionally, immune checkpoint blockade has widely been investigated for its anti-tumor effects against several types of cancers. Here, we investigated for the first time whether the incorporation of influenza hemagglutinin-2 (HA2) FMG could improve the oncolytic...
The Application of Chaos Theory and Nonlinear Structures in Financial Time Series
, M.Sc. Thesis Sharif University of Technology ; Modarres Yazdi, Mohammad (Supervisor)
Abstract
Financial and monetary markets are appropriate areas of applying Chaos Theory. Firstly, current theories of financial and monetary economics state that economic and financial variables such as exchange rates and stock prices are stochastic, so forecasting them is almost impossible. Secondly, if we find the hidden ordered and deterministic trends, we can achieve considerable profits. In this piece of research, we evaluate different methods and tests of detecting chaos in financial time series, and choose the most applicable methods to test financial markets’ indices. The main three indices of Tehran Stock Exchange, including Price, Finance and Industry indices, are examined. A sample of the...
Simulation of flow of short fiber suspensions through a planar contraction
, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 579-584 ; 10263098 (ISSN) ; Ramazani S. A. A ; Kamyabi, A ; Hosseini Amoli, H ; Sharif University of Technology
2012
Abstract
In this study, the flow of a fiber filled viscoelastic matrix through planar contractions is investigated. It was found that by adding fiber to the matrix vortex, the intensity increases. Fiber orientation along "x" and "y" axes was studied too. It was found that fiber orientation could be used for determining the flow regime through the contraction geometry. The rigidity condition of fibers, which needs the trace of the orientation tensor to be unity everywhere in the domain, is correct except near walls and the reentrant corner, which is slightly less than one. In these regions, the stress magnitude is higher, which results in more numerical errors, and which further leads to some error in...
Fully supramolecular vesicles as anticancer drug delivery systems
, Article New Journal of Chemistry ; Volume 37, Issue 2 , 2013 , Pages 295-298 ; 11440546 (ISSN) ; Adeli, M ; Yazdi, M ; Sharif University of Technology
2013
Abstract
A supramolecular linear-dendritic copolymer consisting of a polystyrene backbone and hanging hyperbranched polyglycerols was prepared and characterized. Host-guest interactions between β-cyclodextrin incorporated in the core of polyglycerol as a host and aromatic rings of polystyrene as guests lead to the formation of a supramolecular linear-dendritic copolymer. Supramolecules formed micelles in aqueous solutions which were able to encapsulate and transfer paclitaxel with a high loading capacity
Modeling (r, Q) policy in a two-level supply chain system with fuzzy demand
, Article International Journal of Uncertainty, Fuzziness and Knowlege-Based Systems ; Volume 18, Issue 6 , 2010 , Pages 819-841 ; 02184885 (ISSN) ; Modarres Yazdi, M ; Sharif University of Technology
2010
Abstract
In this paper a two level supply chain system is studied, in which the final demand is assumed to be fuzzy with triangular membership function. The inventory control policy of (r, Q) is followed for this system and unsatisfied demand is assumed to be back ordered. The objective is to minimize the total cost of the system, including ordering, holding and shortage costs. The model happens to be a nonlinear programming. Considering the complexity arising from the model, we also develop a genetic algorithm to obtain a near-optimal solution. The method is illustrated through some numerical examples
Time-variant seismic risk analysis of transportation networks considering economic and socioeconomic impacts
, Article Journal of Earthquake Engineering ; 2018 , Pages 1-29 ; 13632469 (ISSN) ; Mahsuli, M ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
This paper puts forward a new methodology for time-variant seismic risk analysis of transportation networks. Risk here denotes the probability of exceeding the sum of direct loss due to repair costs of bridges in the network and indirect loss due to the reduced capacity for traffic flow. The proposed methodology employs reliability methods and a host of probabilistic models for earthquake events, damage, repair cost, downtime, and travel time, while accounting for time-varying phenomena of aging and discounting. A comprehensive application on the transportation network of Isfahan, Iran, is presented that features 64 bridges subject to seismicity from seven sources. © 2018 Taylor & Francis...
Time-variant seismic risk analysis of transportation networks considering economic and socioeconomic impacts
, Article Journal of Earthquake Engineering ; Volume 24, Issue 5 , March , 2020 , Pages 745-773 ; Mahsuli, M ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
This paper puts forward a new methodology for time-variant seismic risk analysis of transportation networks. Risk here denotes the probability of exceeding the sum of direct loss due to repair costs of bridges in the network and indirect loss due to the reduced capacity for traffic flow. The proposed methodology employs reliability methods and a host of probabilistic models for earthquake events, damage, repair cost, downtime, and travel time, while accounting for time-varying phenomena of aging and discounting. A comprehensive application on the transportation network of Isfahan, Iran, is presented that features 64 bridges subject to seismicity from seven sources. © 2018, © 2018 Taylor &...
Mapping the spatiotemporal variability of salinity in the hypersaline Lake Urmia using Sentinel-2 and Landsat-8 imagery
, Article Journal of Hydrology ; Volume 595 , 2021 ; 00221694 (ISSN) ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The spatiotemporal dynamic of salinity concentration (SC) in saline lakes is strongly dependent on the rate of water flow into the lake, water circulation, wind speed, evaporation rate, and the phenomenon of salt precipitation and dissolution. Although in-situ observations most reliably quantify water quality metrics, the spatiotemporal distribution of such data are typically limited and cannot be readily extrapolated for either long-term projections or extensive areas. Alternatively, remotely sensed imagery has facilitated less expensive and a stronger ability to estimate water quality over a wide range of spatiotemporal resolutions. This study introduces an adaptive learning model that...
Quantifying the uncertainty of lake-groundwater interaction using the forward uncertainty propagation framework: The case of Lake Urmia
, Article Journal of Hydrology ; Volume 610 , 2022 ; 00221694 (ISSN) ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The interaction between a lake and groundwater has important implications to the quantity and quality of water in both environments. Quantification of lake-groundwater interaction (LGI) has been challenging in regions with limited in-situ data. LGI can be quantified by physically-based models, direct measurement of seepage, measurements of conservative chemical or isotopic tracers, and lake water balance. Despite the accuracy of the methods based on hydrochemical or isotopic measurements and analysis, they require extensive field data that are costly to collect in large lakes. Instead, the data required to quantify LGI by the lake water budget method can be obtained via typical ground...
Quantifying the impacts of agricultural alteration and climate change on the water cycle dynamics in a headwater catchment of Lake Urmia Basin
, Article Agricultural Water Management ; Volume 270 , 2022 ; 03783774 (ISSN) ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The rapid shrinkage of Lake Urmia over the past two decades has raised serious environmental concerns. Several restoration plans have been proposed to reduce agricultural water consumption to supply a remarkable fraction of the lake's environmental flow requirement. However, an accurate and realistic evaluation of the effectiveness of these plans in reducing agricultural water consumption across the basin is still poorly understood. This study assessed the water-saving potential of agricultural alteration in a snow-dominated catchment in the Lake Urmia Basin. In particular, we explored the impact of crop pattern alteration via reducing the cultivation area and employing different irrigation...
Evaluating near highway air pollutant levels and estimating emission factors: Case study of Tehran, Iran
, Article Science of the Total Environment ; Volume 538 , December , 2015 , Pages 375-384 ; 00489697 (ISSN) ; Delavarrafiee, M ; Arhami, M ; Sharif University of Technology
Elsevier
2015
Abstract
A field sampling campaign was implemented to evaluate the variation in air pollutants levels near a highway in Tehran, Iran (Hemmat highway). The field measurements were used to estimate road link-based emission factors for average vehicle fleet. These factors were compared with results of an in tunnel measurement campaign (in Resalat tunnel). Roadside and in-tunnel measurements of carbon monoxide (CO) and size-fractionated particulate matter (PM) were conducted during the field campaign. The concentration gradient diagrams showed exponential decay, which represented a substantial decay, more than 50-80%, in air pollutants level in a distance between 100 and 150meters (m) of the highway. The...
Flow of a PTT fluid through planar contractions - Vortex inhibition using rounded corners
, Article ASME 2010 International Mechanical Engineering Congress and Exposition, IMECE 2010, Vancouver, BC, 12 November 2010 through 18 November 2010 ; Volume 7, Issue PARTS A AND B , November , 2010 , Pages 601-607 ; 9780791844441 (ISBN) ; Ramazani S. A, A ; Hosseini Amoli, H ; Behrang, A ; Kamyabi, A ; Sharif University of Technology
2010
Abstract
Contraction flow is one of important geometries in fluid flow both in Newtonian and non-Newtonian fluids. In this study, flow of a viscoelastic fluid through a planar 4:1 contraction with rounded corners was investigated. Six different rounding ratios (RR =0, 0.125, 0.25, 0.375, 0.438, 0.475, 0.488) was examined using the linear PTT constitutive equation at creeping flow and isothermal condition. Then the resulting PDE set including continuity, momentum, and PTT constitutive equations were implemented to the OpenFOAM software. The results clearly show vortex deterioration with increasing rounding diameter, so that when rounding corner exceeds a critical value, the vortex disappears...
Developing air exchange rate models by evaluating vehicle in-cabin air pollutant exposures in a highway and tunnel setting: case study of Tehran, Iran
, Article Environmental Science and Pollution Research ; 2018 ; 09441344 (ISSN) ; Arhami, M ; Delavarrafiee, M ; Ketabchy, M ; Sharif University of Technology
Springer Verlag
2018
Abstract
The passengers inside vehicles could be exposed to high levels of air pollutants particularly while driving on highly polluted and congested traffic roadways. In order to study such exposure levels and its relation to the cabin ventilation condition, a monitoring campaign was conducted to measure the levels inside the three most common types of vehicles in Tehran, Iran (a highly air polluted megacity). In this regard, carbon monoxide (CO) and particulate matter (PM) were measured for various ventilation settings, window positions, and vehicle speeds while driving on the Resalat Highway and through the Resalat Tunnel. Results showed on average in-cabin exposure to particle number and PM10 for...
The capacity of a class of linear deterministic relay networks
, Article ISITA/ISSSTA 2010 - 2010 International Symposium on Information Theory and Its Applications, 17 October 2010 through 20 October 2010, Taichung ; 2010 , Pages 720-725 ; 9781424460175 (ISBN) ; Aref, M. R ; Sharif University of Technology
2010
Abstract
In this paper, we investigate optimal coding strategies for a class of linear deterministic relay networks. The network under study is a relay network, with one source, one destination, and two relay nodes. Additionally, there is a disturbing source of signals that causes interference with the information signals received by the relay nodes. Our model captures the effect of the interference of message signals and disturbing signals on a single relay network, or the interference of signals from multiple relay networks with each other in the linear deterministic framework. For several ranges of the network parameters we find upper bounds on the maximum achievable source-destination rate in the...
The effect of seasonal variation in precipitation and evapotranspiration on the transient travel time distributions
, Article Advances in Water Resources ; Volume 142 , 2020 ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Precipitation (P), plant water use, and evaporation from the soil surface control the travel time of streamflow (Q) and evapotranspiration (ET) in a complex way. However, the impact of soil moisture and energy availability on the travel time distribution (TTD) of evaporated and transpired waters are yet less understood. In this study, we investigate how the seasonal variability of P and ET in terms of phase shift and rate influences the temporal dynamics of TTDs. To this end, we choose four contrasting climate types described as in-phase P and ET, out-of-phase P and ET, year-round constant P with seasonal ET, and year-round constant ET with seasonal P. We use a physically-based hydrological...